• ISSN 1008-9357
• CN 31-1633/O6
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[Abstract](2302) [FullText HTML](387) [PDF 1045KB](10)
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An amphiphilic block copolymer（mPEG-S-S-PS） with a hydrophilic poly(ethylene glycol) methyl ether (mPEG) block, a hydrophobic polystyrene (PS) block and a disulfide linker was synthesized via atom transfer radical polymerization (ATRP). The structure and composition of mPEG-S-S-PS were characterized by nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Through solvent dispersion and microscopic observation, phase inversion of emulsions stabilized by mPEG-S-S-PS was studied. Thanks to the amphiphilic property of mPEG-S-S-PS and the insolubility of PS block in cyclohexane, the diblock copolymer self-assembled to form micelles composing of PS cores and mPEG coronas in water and to form inverse micelles composing of mPEG cores and PS coronas in cyclohexane. Therefore, for cyclohexane-water biphasic system with equal volumes, W/O type emulsions were preferred for copolymer initially dissolved in cyclohexane, while for copolymer initially dissolved in water, O/W type emulsions were obtained. However, for toluene-water biphasic systems, W/O type emulsions were always obtained no matter where the copolymers were dissolved because toluene was a non-selective and good solvent for both PS and mPEG blocks. Based on redox responsiveness of mPEG-S-S-PS copolymer, the addition of reducing agent DTT or GSH could induce the phase inversion of toluene-water emulsion from W/O type to O/W type. The catastrophic phase inversion was obtained in this system by adjusting the oil-water volume ratio. When the fraction of water volume (φw) was less than 0.7, the emulsion was W/O type. However, with φw≥0.7, a catastrophic phase inversion occurred where the system shifted in the opposite direction and O/W type emulsion was obtained. These results will have potential applications in the field of controlling drug release.
[Abstract](856) [FullText HTML](253) [PDF 1613KB](13)
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Carbon monoxide (CO) is a gaseous transmitter that has received mounting interest because of its therapeutic potentials in the treatment of inflammation, bacterial infection, cancer and so on. However, the clinical application of CO is remarkably hindered by the difficulty in precisely controlling CO concentrations and the targeted delivery of CO to pathological tissues. To circumvent these problems, CO-releasing molecules (CORMs) have been developed and have been widely used as the alternative of gaseous CO to explore the physiological functions of CO and develop novel therapeutic agents. Unfortunately, conventional CORMs suffered from insufficient stability, short half-life, and poor biodistribution in biological conditions. Intriguingly, the encapsulation of CORMs into polymeric nanoparticles or covalently installation of CORMs to polymeric matrices remarkably improves the stability of CORMs, prolongs the releasing time and optimizes the biodistributions. In this review article, we summarize the recent achievements of CO-releasing macromolecules and three approaches used for the fabrication of CO-releasing macromolecules have been highlighted. Also, we envision the potential applications of these macromolecular CO donors and suggest future directions in this field. We hope that more efforts would be devoted to this emerging field to advance the clinical trial of macromolecular CO donors.
[Abstract](4318) [FullText HTML](700) [PDF 1002KB](9)
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The surface of the pyromellitic anhydride/4,4'-diaminodiphenyl ether (PMDA/ODA)-based polyimide (PI) film was subjected to alkali-cleaving and ring-opening treatment with potassium hydroxide (KOH) solution. After acidification with acetic acid, a surface-modificated layer of polyamic acid (PAA) was obtained on the surface of PI. Six different metal ions of K+, Na+, Ca2+, Mg2+, Ag+ and Al3+ were introduced into the PAA layer via ion exchange reaction. The ion exchange processes of different metal ions were investigated with Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and inductively coupled plasma emission spectroscopy (ICP). As a result, the load amount of metal ion showed a completely inverse relationship with its valence, indicating that the ion exchange reaction was carried out exactly according to the ionic charge ratio of 1∶1. Meanwhile, the thermal gravimetric (TG) analyzer under a nitrogen atmosphere was performed to investigate the effect of different metal ions on the thermal decomposition temperature of PI film. It was found that the strong alkali metal ions K+ and Na+ provided obvious degradation effects on the PI film, which caused a significant decrease in the thermal decomposition temperature of the PI film. However, the weaker alkali metal ions such as Ca2+, Mg2+, Ag+ and Al3+ exhibited a rather weak influence on the thermal decomposition temperature of the PI film. The effect of metal ions on the thermal decomposition temperature of the film was positively correlated with the aklalinity（pKb）of its corresponding hydioxide, ie K+> Na+ >> Ca2+ ≈ Mg2+ > Ag+ ≈ Al3+.
[Abstract](4084) [FullText HTML](742) [PDF 1291KB](16)
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Well-defined thermo-responsive tadpole-shaped double hydrophilic diblock copolymer (PEG45-b-cPNIPAM) was synthesized through the combination of atom transfer radical polymerization (ATRP) and intramolecular azide-alkynyl click chemistry reaction, where PEG was poly(ethylene glycol) and PNIPAM was poly(N-isopropylacrylamide). Firstly, PEG45(-alkynyl)-Br bearing an alkynyl end group and a bromo side group was synthesized as a macro-initiator to initiate the polymerization of N-isopropylacrylamide (NIPAM). Then, after the preparation of the thermo-responsive linear double hydrophilic diblock polymer, PEG45(-alkynyl)-b-lPNIPAM-Cl, which had an alkynyl and a chloro group at the terminal of PEG and PNIPAM block respectively, the chloro group was modified into azide group by the substitution reaction with sodium azide. Finally, via intramolecular azide-alkynyl click chemistry, PEG45-b-cPNIPAM was obtained, containing a cyclic PNIPAM “head” and a linear PEG “tail”. The structures of PEG45-b-cPNIPAM with different PNIPAM block lengths were characterized by Nuclear Magnetic Resonance (1H-NMR), Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FT-IR) and Laser Light Scattering (LLS) measurements. GPC results indicated that due to the smaller mean square radius of gyration, PEG45-b-cPNIPAM possessed lower molecular weight than its corresponding control linear diblock copolymer with the same length of PEG and PNIPAM block. Moreover, LLS results showed that the solution properties of the polymers were greatly affected by their topological structure. Upon being heated above the phase transition temperature, both the linear and tadpole-shaped diblock copolymer formed aggregates in aqueous solution due to the collapse of the PNIPAM blocks. However, the hydrodynamic radius of the aggregates obtained from PEG-b-cPNIPAM was much smaller than that obtained from linear diblock copolymers with the same block length for lack of inter-chain entanglement. Besides, concerning the tadpole-shaped PEG45-b-cPNIPAM110 with longer PNIAPM block length, after the rapid phase transition, the collapsed polymer chains in the aggregates could further undergo conformation adjustment, thus resulting in the decrease of aggregates size with the increasing solution temperature.
[Abstract](1970) [FullText HTML](322) [PDF 1056KB](16)
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Graphene oxide (GO) nanosheets with varied mass fractions were introduced into the shape memory capable poly(lactide-co-caprolactone) (PLCL) copolymer to prepare GO/PLCL composite nanofibers via electrospinning. Based on the tensile and shape memory properties of the produced GO/PLCL nanofiber films, an optimal GO mass fraction(m(Go)∶m(PLCL)), (0.5%) was determined to maximize the reinforcing effect of the GO nanosheets to the PLCL fiber matrix. Thereafter, an alkaline amino acid lysine (Lys) was selected to functionalize the GO (0.5%) via 1-(3-dimethy laminopropyl)-3-ethylcarbodiimide/N-hydroxysuccinimide chemistry followed by electrospinning for the generation of multifunctional Lys-GO/PLCL nanofibers. A series of characterization including mechanical properties, shape memory performance, acidity neutralization capacity and osteogenic differentiation were subsequently carried out with the produced Lys-GO/PLCL nanofibers. The results showed that among the four groups of GO/PLCL nanofibers loaded with different GO mass fractions (i.e., 0, 0.5%, 1% and 2%), incorporation of 0.5% GO within the PLCL nanofibers gave rise to the most remarkable enhancement efficiency, as evidenced by the noted 28.4% increase in Young's modulus and 28.3% increase in shape recovery stress. With the introduction of merely 0.5% of Lys-GO into the PLCL nanofibers, it was found that the fiber morphology, tensile properties and shape recovery stress of the GO/PLCL could be largely preserved (>85%). Most importantly, it was demonstrated that the developed Lys-GO/PLCL nanofibers not only enabled neutralize the acidic degradation products of the PLCL (e.g., the pH acidity was neutralized to 5.2 for the Lys-GO/PLCL nanofibers, compared to that of the GO/PLCL counterpart with a pH of 4.2), but also possessed good cytocompatibility and osteogenic differentiation capacity in the mouse bone mesenchymal stem cells (rBMSCs). This newly developed shape memory capable Lys-GO/PLCL fibers may find applications in the construction of multifunctional bone tissue engineering scaffolds.
[Abstract](1198) [FullText HTML](363) [PDF 1209KB](6)
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In this paper, raspberry-like polydopamine/copper nanoparticles (PDA-Cu NPs) were constructed by simply adjusting the contents of copper source and reduction temperature on the basis of good adhesion properties of polydopamine (PDA) with metal particles. The successful introduction of copper nanoparticles was confirmed by measurements of X-ray diffraction (XRD) and Zeta potential. Scanning electron microscopy (SEM) results showed that the raspberry-like structure had been successfully constructed. Moreover, the results showed that when the reduction temperature was 60 °C, the copper nanoparticles had more uniform particle size. When the mass ratio of copper nitrate to PDA was less than 6/1, the copper nanoparticles were evenly distributed on PDA particles. The static contact angle measurements revealed that the introduction of copper nanoparticles increased the surface roughness of the PDA particles, and the surface contact angle was up to 102.2°, showing that the modified particles turned from hydrophilic to hydrophobic. At the same time, copper nanoparticles had good antibacterial properties. The antibacterial activity of raspberry-like nanoparticles was evaluated by shake flask method. Compared with pure dopamine nanoparticles, PDA-Cu NPs had excellent antibacterial properties. With the increase of copper content, 100% sterilization could be achieved, and antibacterial performance against S. epidermidis was better than that of E. coli. The bacterial zone experiments showed that when the mass ratio of copper nitrate to PDA was 6/1, it had a clear zone of inhibition and the diameter was larger than that of 8/1, suggesting the optimal antibacterial properties. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of raspberry-like nanoparticles made from optimal reaction conditions for E. coli were 48.7 μg/mL and 195.0 μg/mL, respectively, while the MIC and MBC values for S. epidermidis were 39.0 μg/mL and 97.5 μg/mL, respectively. Raspberry-like nanoparticles showed good abtibacterial properties, which were expected to have a good application in biomedical fields.
[Abstract](959) [FullText HTML](273) [PDF 982KB](5)
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A series of linear poly(dimethylsiloxane) (PDMS-g-Vi) with different vinyl contents were synthesized via ring-opening copolymerization of tetravinyltetramethylcyclotetrasiloxane (V4) and octamethylcyclotetrasiloxane (D4) catalyzed by a cyclic trimeric phosphazene base (CTPB). Further, the carboxylic acid- or amine-functionalized PDMS (PDMS-g-COOH and PDMS-g-NH2) was prepared through the thiol-ene click reaction, confirmed by gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (1H-NMR). Finally, the target silicone elastomers (PDMS-g-[COOH/NH2]) were prepared based on the reversible ionic hydrogen bonds between COOH and NH2 side chain groups, exhibiting remarkably fast self-healing capability at room temperature without any external stimulus. The mechanical strength, elasticity and self-healing properties of resultant elastomers could be tuned by modulating the hydrogen bonding density and the molecular weight of PDMS-g-Vi precursors. The PDMS-g-[COOH/NH2] elastomer owned a breaking stress of 230.9 kPa at 877% elongation at break with a stretching speed of 50 mm/min, and the elongation at break was higher than 500% even under a fast stretching speed (200 mm/min). Moreover, its self-healing efficiency reached as high as 99% after restored at room temperature for 30 min.
[Abstract](1922) [FullText HTML](321) [PDF 1127KB](5)
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An ortho-diamine monomer, 4-phenoxy-1,2-phenylenediamine (POPDA) was synthesized via two-step reactions. It was randomly copolymerized with 4,4’-dicarboxydiphenyl ether (DCDPE), 5-aminoisophthalic acid (APA) and 3,3’-diaminobenzidine (DAB) in polyphosphoric acid to yield a new kind of high molecular weight poly(ether ketone benzimidazole) copolymers (PEKBI-x, ‘x’ refers to the molar fraction of POPDA in aromatic diamines (POPDA and DAB), the same below). The resultant PEKBI-x was sulfonated using fuming sulfuric acid as the sulfonating reagent to give the corresponding sulfonated poly(ether ketone benzimidazole)s (SPEKBI-x). No significant polymer degradation was observed during the process of sulfonation reaction indicating excellent chemical stability of the copolymers PEKBI-x. A series of covalently cross-linked membranes (SPEKBI-x-CL) were prepared via the solution cast method, and the cross-linking reaction occurred between the amino groups of the APA moiety of the SPEKBI-x and the epoxy groups of the cross-linker 1,2,7,8-diepoxyoctane during the process of solvent evaporation. The thermal stability, mechanical properties, water uptake, swelling ratio, proton conductivity, ion exchange capacity, radical stability, and single cell performance of the exchange proton membranes were investigated. Results showed that these cross-linked membranes exhibited very high ion exchange capacities (2.88～3.28 meq/g) and good mechanical and thermal properties. With the increase of POPDA content in the copolymers, the proton conductivity of the proton exchange membrane increased. A preliminary test of H2-O2 single cell revealed that the maximum output power density of the single cell assembled with the SPEKBI-0.50-CL membrane reached 662 mW/cm2 at 80 ℃, 80% relative humidity and 100 kPa back pressure, which was slightly higher than that of the one assembled with Nafion212 (631 mW/cm2) under the same test conditions.
[Abstract](2052) [FullText HTML](262) [PDF 1487KB](2)
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As one of the quasi-zero-dimensional materials, [60]fullerene (C60) and its organic/polymeric derivatives exhibit great application potential in many high-technology fields due to their outstanding optical, electronic, optoelectronic and magnetic properties. A new triphenylamine-fluorene copolymer-[60]fullerene covalently bridged triad (C60-PTF-C60) was synthesized by the 1,3-dipole addition reaction of C60, sarcosine and PTF terminated with two aldehyde groups (CHO-PTF-CHO). This material which was highly soluble in some common organic solvents, was embedded into an optically nonactive transparent poly(methylmethlacrylate) (PMMA) matrix to produce the PMMA-based C60-PTF-C60 film for nonlinear optics. The nonlinear optical (NLO) and optical limiting (OL) properties of C60-PTF-C60 were investigated through an open-aperture Z-scan setup at 532 nm.The C60-PTF-C60/PMMA film exhibited more excellent NLO and OL responses when compared with the C60/PMMA film under the same experimental conditions due to photo-induced electron transfer between C60 and PTF in the copolymer structure. The achieved nonlinear coefficient (βeff), imaginary third-order susceptibility (Imχ(3)), and OL threshold were 437.75 cm/GW, 1.87×10−10 esu, and 0.34 GW/cm2, respectively. For comparison purpose, the corresponding βeff, Imχ(3), and limiting threshold of the C60/PMMA film were 188.87 cm/GW, 0.81×10−10 esu, and 0.53 GW/cm2, respectively.
[Abstract](3224) [FullText HTML](623) [PDF 773KB](31)
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With the increasing pollution of marine plastic, the degradation properties of biodegradable plastic in seawater have attracted much attention and controversy. Four typical biodegradable plastic polylactide (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS) and poly(ε-caprolactone) (PCL) were selected. The seawater degradability of the materials was studied by investigation of the change in their mass loss, molecular weight, mechanical properties, and spline morphology after 364 d immersed in natural seawater. Further, the effects of environmental factors on the degradation properties of four polyesters were studied in natural water, static seawater, static river water, distilled water, sterilized seawater, and lab-prepared seawater. Results show that the degradability of biodegradable polyester in natural seawater is significantly lower than that in compost. The most market-demand PLA almost exhibits no degradation after 364 d. The mass losses of PBAT and PBS are no more than 3% after 364 d. PCL degradation is the fastest and the mass loss of PCL degradation is 32%. Microorganisms seem to be the key factors affecting the rate of biodegradation. It is also found that the high concentration of inorganic salt has a promotion to the non-enzymatic hydrolysis process.
[Abstract](732) [FullText HTML](209) [PDF 1662KB](4)
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The microstructure on the implants is essential for bone repairing and tissue regeneration. Especially, controllable preparation of well-defined micropattern is one of the key factors to regulate the biological fate of bone mesenchymal stem cells (BMSCs). Usually, the micropatterns are made of materials with limited degradability and poor bioactivity. In order to meet the needs for bone repairing and take the special structural and physiochemical properties of biomedical implants into account, the degradable hyaluronic acid (HA) was chosen as the raw material, cross-linked with N′-(ethyliminomethylidene)-N, N-dimethyl-1,3-propylene diamine (EDCI) and adipic acid dihydrazide (ADH). Soft-lithography technique was used to fabricate the HA microwell patterns. By turning the mass fraction of ADH and EDCI from 8.3% to 16.7% respectively, the effects of contents on the microstructure, swelling properties, degradation behavior, and compatibility of HA films were evaluated by a series of characterization methods.The experimental results showed that as the mass fraction of ADH and EDCI increased, the crosslinking degree of the film increased, and the swelling variation of gel became smaller. HA films with high mass fraction of ADH and EDCI showed a slower degradation behavior. A series of HA films with micro-array pore structure (pore diameter of 32, 96, 128, 320 μm respectively) were successfully fabricated by combining soft lithography and solvent evaporation. When co-culture with rBMSCs in vitro, the results showed that the larger micron wells (96, 320 μm) with sparse distribution presented no significant effect on the proliferation of rat bone mesenchymal stem cells (rBMSCs) compared to the smooth HA gel film, while the small micron wells (32 μm) with compact distribution can significantly promote the proliferation and osteogenic activity of rBMSCs.
[Abstract](401) [FullText HTML](121) [PDF 689KB](4)
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High efficiency, high stability and low cost are the three key factors for polymer solar cell (PSC) that determine whether this technology could be commercialized. In recent years, the power conversion efficiency of PSC has reached a high level over 17%. However, the high-efficiency devices are realized mainly based on photovoltaic donor and acceptor materials with complex structures and high-cost, so it becomes a major challenge to reducing the cost of photovoltaic materials for the commercialization of PSC. Since 2018, a research group of Professor Li Yongfang from the Institute of Chemistry, Chinese Academy of Sciences reported a series of photovoltaic polymer donors based on poly(thiophene-quinoxaline) derivatives, showing high-efficiency, high stability and low-cost for potential commercial application. Based on the synthesis of new polymers, they also discussed the effect of fluorination and methylation on the energy level and photovoltaic performance of new polymer donors. The works provide new concept for the design of polymer donors with potential for commercial application.
[Abstract](422) [FullText HTML](135) [PDF 1030KB](8)
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In some extreme environments, polymers are easy to suffer from irreversible damage or degradation, which increases potential safety problems and reduces the service life of the materials. Aiming at the problem of low self-healing rate of the polymer at low temperature, the polymer network with multiple cross-linked hydrogen-bonded was prepared by mixing up the polydimethylsiloxanes with amino-terminated flexible molecular chains and malonyl chloride and it was subjected to condensation polymerization at the temperature of −5 ℃ and in Ar atmosphere. The flexible molecular chain effectively reduces the glass transition temperature (Tg≈−120 ℃), indicating that the ability to move of the molecular chain still exists under the low temperature conditions, and it is a prerequisite for polymers′ self-healing under low temperature conditions. The results show that the self-healing efficiency of the tensile strength of the polydimethylsiloxane cross-linked polymer at −25 ℃ after 40 min is as high as 97%. Through the reversible fracture and formation of multiple hydrogen bonds between N—H and C=O, the rapid self-healing of polymers at room temperature and high-efficiency self-healing at low temperature can be achieved. This study will provide an insight for further preparation of the autonomous self-healing materials under the extreme environments in the future.
[Abstract](401) [FullText HTML](114) [PDF 1231KB](1)
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Bio-based polyurethane with good comprehensive performance has attracted increasing attention. Cottonseed oil-based polyurethane (TO-PU) elastomers were synthesized from ozonized cottonseed oil-based polyols (OTO-polyols) with high hydroxyl value and castor oil (CO) by reacting with isophorone diisocyanate (IPDI). The structure of urethane bond was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the formation of hydrogen bond was also observed. The thermo-mechanical properties of synthetic TO-PU were examined by differential scanning calorimeter , thermogravimetric analyzer and universal testing. The thermo-mechanical properties are strongly dependent on the crosslinking density of TO-PU. The glass transition temperatures of polyurethane elastomers are −35 — −28 ℃, and the crystalline properties can be enhanced with the increasing of castor oil. Correspondingly, the mechanical properties of TO-PU according with the tensile behavior of elastomers can be adjusted by the mass ratio of OTO-polyols to CO. The tensile strength of TO-PU-3 exceeds to 2.50 MPa, while the elongation at break can maintain above 150%. In comparison, the elongation at break of TO-PU-1 can approach 400% by reducing the content of castor oil. The cottonseed oil-based polyurethane elastomer shows excellent thermal stability with the initial decomposition temperature above 240 ℃, and its three thermal degradation stages are caused by urethane groups, ester groups, and long carbon chains of polyols, respectively.
$v.latestStateEn doi: 10.14133/j.cnki.1008-9357.20200612001 [Abstract](295) [FullText HTML](37) [PDF 1223KB](1) Abstract: Vascular disrupting agents (VDAs) have aroused increasing interest due to their great potential in cancer therapy. As compared to combretastatin A4 phosphate (CA4P) which has been in Phase III clinical trials, a polymeric VDA prodrug, poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4 (C-NPs), can significantly improve the tumor blood vessels targeting and enhance therapeutic effect due to the low permeability of nanodrug in solid tumors. However, C-NPs was found to induce the polarization of TAMs toward an M2-like phenotype (M2-TAMs) and further tumor recurrence, which restrained its antitumor application. BLZ945 was a highly selective CSF-1R inhibitor which can inhibit CSF-1/CSF-1R signal pathway to decrease the number of M2-TAMs. However, CSF-1R is widely expressed on most cells of mononuclear phagocytic system which result in the lack of tumor selectivity and therapeutic side effect of BLZ945. Firstly, the reduction of M2-TAMs after BLZ945 treatment was verified by flow cytometry analysis; and in vivo antitumor efficacy showed that the combination of C-NPs and BLZ945 remarkably enhanced anticancer efficacy with an 74.1% of tumor suppression rate. Then, the co-bonded nanodrug poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol)-combretastatin A4/BLZ945 (CB-NPs) was developed for further enhance the synergistic anticancer efficacy. The chemical structure of CB-NPs was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The obtained CB-NPs had a hydrodynamic radius (Rh) of 56 ± 19 nm in aqueous solution determined by dynamic light scattering (DLS). The drug loading content (DLC) of CA4 and BLZ945 in CB-NPs measured by HPLC was 10.7 wt.% and 8.4 wt.%, respectively. An in vivo study with the C26 murine colon carcinoma model showed that CB-NPs exhibited the most prominent suppression of tumor growth, significantly higher than the combination therapy with C-NPs plus BLZ945, the tumor suppression rate to C26 tumor with an initial volume of 410 mm3 was 79%. Therefore, CB-NPs enhanced tumor targeting ability of BLZ945 and improved its synergistic antitumor ability. This work provides a valuable cooperative strategy therapeutic choice of VDAs for solid tumor therapy. [Abstract](382) [FullText HTML](114) [PDF 1176KB](5) Abstract: As a lightweight energy system, lithium ion batteries are used in different industries and fields. The electrolyte acts as a channel for ion transmission in the battery. Polymer materials are applied as electrolyte since they have the advantages of high safety, high thermal stability and high mechanical strength. However, polymer will crack in certain external environments. Then some researchers proposed to prepare self-healing materials and apply them to electrolyte in lithium ion battery. This work was dedicated to solve the problem that the polymer electrolyte is susceptible to mechanical damage. The preparation method of 2-ureido-4-[1H]-pyrimidinone (Upy) unit which contains the quadruple hydrogen bonds was raised. And grafted Upy on the Polyvinyl alcohol (PVA) polymer matrix to prepare an self-healing electrolyte material. The chemical structure, the thermal stability, the self-healing ability and electrochemical performance of PVA-Upy membrane were studied. The results show that PVA-Upy material is successfully prepared by this method and proved by FT-IR and 1H-NMR measurement. PVA-Upy material has good thermal stability and mechanical strength, and has a self-healing efficiency of 90.20% in tensile strength at 70 ℃. As for electrolyte, it has an electrochemical window of 5 V and its highest ion conductivity is 2.06×10−3 S cm−1. Assembling it as LiFePO4/PVA-Upy/Li cell, it showed good cycle stability which means the application prospect in lithium ion batteries.$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20200313002
[Abstract](348) [FullText HTML](136) [PDF 1211KB](7)
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An orthoester monomer of (2-(octadecyloxy)-1,3-dioxolan-4-yl) methanamine (OE) was synthesized using the 3-amino-1,2-propanediol as starting material. A novel pH-sensitive polymer mPEG-GDE-OE was prepared by ring opening polymerization of OE, methoxypolyethylene glycol amine (mPEG-NH2) and glycol diglycidyl ether (GDE). The pH-insensitive polymer mPEG-GDE-OA was synthesized as a reference polymer. Amphiphilic polymer mPEG-GDE-OE and mPEG-GDE-OA could self-assemble into micelles by solvent volatilization method. Then doxorubicin (DOX) was used as a model drug to incorporate into mPEG-GDE-OE and mPEG-GDE-OA micelles. Those polymers were characterized by 1H-NMR. The size and the morphologies of the micelles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The drug release properties of micelles were investigated in vitro. Human breast cancer cells (MCF-7) and cervical cancer cells (Hela) were used as model tumor cell lines to investigate the cytotoxicity and antitumor activity of drug loaded polymer micelles in vitro. Results show that the particle sizes of mPEG-GDE-OE and mPEG-GDE-OA micelles are (168.2 ± 4.6)nm and (157.5 ± 3.4)nm. The particle sizes of drug-loaded micelles, DOX/mPEG-GDE-OE and DOX/mPEG-GDE-OA, are (191.6±6.7)nm and (182.8±5.2)nm. Compared with mPEG-GDE-OA micelles, mPEG-GDE-OE micelles have good pH sensitivity, good controlled release performance and strong tumor killing ability.
[Abstract](904) [FullText HTML](268) [PDF 1101KB](8)
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In order to achieve high efficiency in the cycloaddition reaction of CO2 under the conditions of mild environment and absence of cocatalyst, two kinds of porphyrin-based porous organic polymers (PPOP-COOH and PPOP-I) were designed and synthesized in this paper. The nucleophilic groups and metal active centers of quaternary ammonium salts were introduced into the polymers by means of pre-modification and post-modification. The two crosslinked polymers showed excellent chemical and thermal stability. The chemical structures and pore structures of the two polymers were characterized, and both of them had hierarchical porous structure with specific surface areas of 302～514 m2/g. Under the condition of 298 K, CO2 adsorption and desorption tests were carried out, and the results showed that CO2 adsorption capacity of carboxyl-containing polymer was greater than that of quaternary ammonium salt containing polymer. The effect of the catalyst on the cycloaddition reaction of CO2 was studied. The results showed that the synergistic effect of Lewis acid metal ions, nucleophiles and multi pore structure greatly promoted the CO2 cycloaddition reaction. It is important to note that although containing quaternary ammonium salt ions than CO2 adsorption capacity of polymer containing carboxyl, but its catalytic performance is far higher than that of polymer containing carboxyl. Under moderate conditions (80 ℃, 0.3 MPa, 24 h), the reaction selectivity and conversion can reach higher than 99%, and still presented good catalytic performances after repeated use for many times.
[Abstract](777) [FullText HTML](174) [PDF 1446KB](0)
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Firstly, Fe3O4 nanospheres were prepared by solvothermal method, which were used as magnetic cores and coated with chitosan (CS) crosslinked by glutaraldehyde. Then, polyoxometalate (POM) was supported onto the magnetic cs carriers by electrostatic bonding and three magnetic polyoxometalates microspheres (Fe3O4@CS@POM) were prepared, including Keggin type magnetic phosphotungstic acid (Fe3O4@CS@PW12) and Dawson type magnetic phosphotungstic acid (Fe3O4@CS@P2W17 and Fe3O4@CS@P2W18). Their structures and morphologies were characterized by FT-IR、UV-Vis、EA and TEM. The catalytic activity of Fe3O4@CS@POM on tetrahydrothiophene (THT) was investigated in detail. It is shown that all the three kinds of Fe3O4@CS@POM microspheres have good catalytic oxidation abilities to THT, among which Fe3O4@CS@PW12 shows the best catalytic activity. The conversion of THT could reach 100% at room temperature after 105 min with a small amount of Fe3O4@CS@PW12 (0.01 g). The catalytic oxidation process follows the quasi-first order kinetic model. The catalyst could be separated quickly and efficiently in the external magnetic field. In addition, Fe3O4@CS@PW12 has good reusability, and the catalytic activity remains stable after 5 cycles.
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2020, 33(4): 313-315.   doi: 10.14133/j.cnki.1008-9357.20200528001
[Abstract](818) [FullText HTML](182) [PDF 662KB](11)
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Per- and polyfluorinated alkyl substances (PFASs), notably perfluorooctanoic acid (PFOA), contaminate many ground and surface waters and are environmentally persistent. The cost and performance limitations of current PFAS removal technologies motivate efforts to develop adsorbents with high selectivity and affinity. Recently, Chen’s group at Fudan University reported a fluorous-core nanoparticle-embedded hydrogel (FCH) synthesized by the metal-free tandem photo-controlled radical polymerization under visible-light irradiation. This FCH material exhibits outstanding adsorption performance on PFASs with different electronic characteristics including neutral, anionic, cationic and zwitterionic ones. Moreover, the adsorption performance of the FCH material is barely affected even after more than five adsorption-desorption cycles. These results demonstrate the promise of the FCH material for treating PFAS-contaminated water.
2020, 33(4): 316-319.   doi: 10.14133/j.cnki.1008-9357.20200601002
[Abstract](765) [FullText HTML](157) [PDF 14118KB](7)
Abstract:
π-Conjugated polymers have gained extensive attention due to potential applications in electroluminescent materials, field effect transistor, etc. The precise preparation of fiber-like π-conjugated fiber-like hybrid nanostructures of controlled length and composition has always been one of the research directions to improve the performance of materials, and still remains a challenge. Recently, Prof. Huang and Prof. Feng’s group from Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, demonstrated an efficient and versatile platform for the construction of oligo(p-phenylenevinylene)(OPV)-based multi-component and multi-function fiber-like hybrid nanostructures by the combination of non-covalent interaction and “living” crystallization-driven self-assembly (CDSA). Through self-seeding and seeded growth approaches, uniform continuous micelles and segmented A-B-A, B-A-B-A-B multiblock fiber-like comicelles were able to be generated with tunable lengths for each block. By taking advantage of pyridyls of poly(2-vinylpyridine) (P2VP)-forming coronas, P2VP domains in these micelles or comicelles could be functionalized with diverse inorganic(CdTe, Au, Ag and Fe3O4) and polymeric nanoparticles as well as metal oxide coatings (SiO2 and TiO2) to afford hierarchical hybrid nanostructures. This work provides a versatile strategy toward the fabrication of multi-component, multi-function π-conjugated fiber-like nanostructures with the capacity to be selectively functionalized.
2020, 33(4): 320-332.   doi: 10.14133/j.cnki.1008-9357.20190705001
[Abstract](6609) [FullText HTML](1352) [PDF 3676KB](121)
Abstract:
Polyimides (PIs) have extensive applications in the aerospace industry, microelectronic and optoelectronic engineering, liquid crystal display, and separation membrane due to their high-temperature resistance, outstanding mechanical properties, chemical and radiation resistance, and excellent dielectric properties. Conventional PIs possess strong inter- and intra- molecular charge transfer interactions, resulting in an intense stack of the molecular chains, which leads to strong absorption in the visible region and brings deep color to PIs. This has considerably restricted their applications in the area of optoelectronic and microelectronic engineering. With the rapid development of display technology, PIs with excellent optical and thermal performance are desired to serve as substrate materials. However, achieving a breakthrough in the molecular design of the satisfied PIs remains challenging with regarding to the trade-off between good transparency and thermal stability of PI films. Recently, enormous research efforts have been devoted to the development of colorless and transparent PIs with high thermal stability via rational molecular structure design, as summarized in this review. These fabrication strategies mainly include the introduction of strong electronegative groups, alicyclic structures, bulky pendent units, asymmetric and rigid noncoplanar segments, and polymerizable inorganic nanoparticles. The incorporation of these structures plays an important role in disrupting the conjugation between the PI chains. This disruption reduces the regularity and weakens the stack of the molecular chains, while increasing the free volume of the PI chains, thus prohibiting the formation of inter- and intra- molecular charge transfer complex. All these are beneficial to minimize the absorption in the visible region and the formation of colorless PIs. Then, the influences of molecular structures on the properties of PI, such as thermal properties, optical performance and solubility, are discussed. Finally, the prospect of colorless and transparent PI with high thermal stability is discussed with respect to their development trends and potential applications.
2020, 33(4): 333-341.   doi: 10.14133/j.cnki.1008-9357.20190424004
[Abstract](6729) [FullText HTML](1177) [PDF 1327KB](46)
Abstract:
Semiconductor photocatalysts can directly use sunlight to produce clean and renewable energy, offering a potentially viable solution for addressing energy and environmental crisis. Recently, conjugated microporous polymers have emerged as a very promising class of materials in solar energy conversion. However, they generally exhibit low catalytic efficiency and insufficient catalytic stability. Moreover, they lack the capability to utilize long-wavelength photons in the near-infrared region. In this work, aza-fused conjugated microporous polymer (aza-CMP) is synthesized via condensation of 1,2,4,5-benzenetetramine and cyclohexanone. The as-obtained aza-CMP exhibits a band-gap as low as 1.22 eV, ensuring that it can absorb both visible light and near-infrared photons. Meanwhile, results show that aza-CMP can effectively drive the degradation of various organic dyes such as Congo Red, Rhodamine B, and Methyl Orange under visible and near-infrared light irradiation. In contrast, other photocatalysts such as P25-TiO2, g-C3N4, and Ag-TiO2 are unable to oxidize organic dyes under near-infrared light irradiation, suggesting that aza-CMP is very efficient in absorbing visible and long-wavelength photons for photocatalytic oxidation of organic pollutants. In addition, multiple cycling experiments confirm that aza-CMP is very stable during the catalytic process, which can retain its structure and high catalytic activity after multiple cycles. Mechanistic investigations further reveal that the active species toward photocatalytic degradation of organic dyes are the photogenerated holes and singlet oxygen. Furthermore, the pathways of the photocatalytic degradation of organic dyes are unveiled by using liquid chromatography-mass spectrometry (LC-MS), clearly demonstrating the capability of aza-CMP in oxidizing organic dyes into small molecules. This study potentially provides new prospects in the design and synthesis of conjugated polymers for various photocatalytic applications.
2020, 33(4): 342-349.   doi: 10.14133/j.cnki.1008-9357.20190819001
[Abstract](4391) [FullText HTML](897) [PDF 1117KB](17)
Abstract:
A highly efficient and simple method for preparing small-size Janus gold nanoparticles (AuNPs) capable of self-assembling was developed. Firstly, the asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were fabricated based on β-cyclodextrin (β-CD) by combining atom transfer radical polymerization (ATRP) and click chemistry. Secondary, the hydroxyl groups on the wide cross-section of the β-CD molecule were modified to be ATRP initiator moieties, which then initiated the polymerization of N-isopropyl acrylamide (NIPAM) to form fourteen PNIPAM chains via ATRP. The primary hydroxyl groups on the narrow cross-section of the β-CD molecule were converted into azide groups and then coupled with 5-(1,2-dithiolan-3-yl)-N-(prop-2-ynyl) pentanamide molecules by click chemistry. The obtained asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were used to modify AuNPs that were formerly surface-stabilized by n-butylthiol through the ligand exchange process. Due to the steric effect of (LA)7-CD-(PNIPAM46)14 macromolecules, Janus hybrid AuNPs, Au3.1-CD-(PNIPAM46)14, with amphiphilic surface were prepared, which could self-assemble in water into micelle-like aggregates, i.e. supermicelles. The chemical and chain structures of asymmetric (LA)7-CD-(PNIPAM46)14 star polymers and the amphiphilic Janus hybrid Au3.1-CD-(PNIPAM46)14 nanoparticles were characterized by Nuclear Magnetic Resonance (NMR), Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS), Gel Permeation Chromatography (GPC) and Thermal Gravimetric (TG) analysis. The morphology and structure of the prepared micelle-like self-assemblies were investigated by Transmission Electron Microscope (TEM).
2020, 33(4): 350-356.   doi: 10.14133/j.cnki.1008-9357.20190617001
[Abstract](5377) [FullText HTML](760) [PDF 945KB](17)
Abstract:
Periodic micro-grooves with different widths (20, 40 μm and 60 μm) on the surface of polyetheretherketone (PEEK)/mesoporous calcium magnesium silicate (m-CMS) composite were prepared by femtosecond laser. The effects of the width of micro-grooves on the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) were investigated. Results showed that the micro-nanostructures were formed in the inner surface of the micro-grooves after ablating using femtosecond laser, which exhibited a large number of mesoporous calcium magnesium silicate particles. In addition, the roughness (Ra = 5.15 μm) of the inner surface of the micro-grooves was significantly improved as compared with the grooved ridge (Ra = 1.53 μm) that was absent of treatment by femtosecond laser. Moreover, with the increase of the width of the micro-grooves, the protein adsorption of the composite surface was obviously enhanced, which significantly promoted the adhesion of rBMSCs on the composite surface. Furthermore, when the width of the micro-grooves was 20 μm, the cells did not display specific growth orientation on the composite surface. When the width of the micro-groove was 40 μm, a small number of cells grew along the groove orientation. When the width of the groove was 60 μm, a large number of cells grew along the groove orientation, and the cell body was plump with filamentous pseudopodia extending, which indicated that the composite surface not only significantly promoted the adhesion, spreading, proliferation and osteogenic differentiation of cells, but also induced the growth of cells along the groove orientation. In short, periodic micro-grooves on the composite surface were prepared by femtosecond laser, and the width of micro-grooves on the composite surface could regulate and control the behaviors of cells, in which appropriate width (e.g. 60 μm) of micro-grooves was conducive to stimulate cell responses.
2020, 33(4): 357-364.   doi: 10.14133/j.cnki.1008-9357.20191115002
[Abstract](2377) [FullText HTML](298) [PDF 1142KB](8)
Abstract:
A novel type of microcapsule with pH-responsive release and anti-corrosion function was prepared via the UV-initiated polymerization and interfacial polymerization of Pickering emulsion. Then the microcapsule was loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) and embedded into epoxy coating for enhancing the anti-corrosion performance of coating. SiO2 nanoparticles were used as the Pickering emulsifier to stabilize the oil phase of emulsion, which contained aniline, glycidyl methacrylate (GMA) and 1,6-hexanediol diacrylate (HDDA). GMA and HDDA underwent crosslinking along with the interior of the emulsion droplets and formed the first shell of microcapsule initiated by UV light. The polyaniline (PANI) was synthesized subsequently via chemical oxidative polymerization of aniline initiated by ammonium persulfate (APS) and acted as the second functional layer of microcapsule shell material. The shell of the as-prepared PGMA@PANI microcapsule is thus of composite structure. The PGMA shell stabilized the morphology of the emulsion droplets and improved the robustness of the microcapsule. The PANI shell functioned as anti-corrosion filler and a pH-sensitive gatekeeper to realize the responsive release of corrosion inhibitor. After being loaded MBT, the MBT-PGMA@PANI microcapsule could achieve dual anti-corrosion function. PANI could passivate the steel and released MBT could form dense barrier layer on the steel surface to resist corrosive medium. Electrochemical impedance spectroscopy (EIS) was used to test the performance of coating. The Bode plots showed that the impedance values at low frequency (|Z|f=0.1 Hz) of coating with 1% mass fracion of MBT-PGMA@PANI microcapsule could be maintain above 108 Ω·cm2 after immersed in NaCl solution (w=3.5%) for 30 d, demonstrating significant improvement of anti-corrosion performance.
2020, 33(4): 365-372.   doi: 10.14133/j.cnki.1008-9357.20190809001
[Abstract](5748) [FullText HTML](814) [PDF 1249KB](11)
Abstract:
Two well-defined comb-like polyester diols (GS) with C-18 side chains were synthesized by reacting glyceryl monostearate (GMS) with succinic anhydride. NCO-terminated polyurethane prepolymers (PUGS) with C-18 side chains in soft segment structure were synthesized from diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO) and GS. Then polyurethane hybrid materials (PUGS-Ti) were further prepared by mixing with nano-TiO2. The structures of GS and PUGS were characterized by 1H-NMR and FT-IR. The crystallization behavior, surface morphology and surface contact angle of the prepared PUGS and its hybrid material were characterized by DSC, WAXD, SEM, AFM and water contact angle measurements. The effects of alkyl side chain content and the amount of TiO2 on the surface properties of PUGS and its hybrid material were investigated. Results showed that the introduction of non-polar alkyl side chains into the polyurethane could significantly reduce the surface energy and improve the contact angles of water on the surface. In PUGS-Ti, the surface energy of the materials could be effectively adjusted to achieve superhydrophobicity of the surface by adjusting the content of soft segments (the number of alkyl side chains) and the amount of TiO2 in the structure.
2020, 33(4): 373-381.   doi: 10.14133/j.cnki.1008-9357.20190619002
[Abstract](5357) [FullText HTML](899) [PDF 1563KB](49)
Abstract:
Firstly, a series of bio-based poly(isosorbide dicarboxylate) diols (PISA) were synthesized by the reactions between bio-based isosorbide (IS) and five kinds of dicarboxylic acids with different methylene chain lengths. Then, bio-based polyurethane (Bio-PU) was prepared by the reaction between 4,4'-diphenylmethane diisocyanate (MDI) with PISA and 1,4-butanediol (BDO) as the chain extender. The structure and thermal properties of PISA samples were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR) and differential scanning calorimeter (DSC). The structure and properties of Bio-PU were characterized by FT-IR, DSC, dynamic mechanical thermal analyzer (DMA), atomic force microscope (AFM), water contact angle test and measurement of mechanical properties. Results showed that Mn of PISA were in the range between 672 and 940. As the carbon numbers in repeating units of PISA increased from 4 to 12, the glass transition temperature (Tg) of PISA samples decreased from 10.5 °C to −40.9 ℃. The viscosity also decreased, but the crystallinity increased. When the length of methylene chain in the repeating unit of PISA increased, the hydrogen bonding of Bio-PU decreased. Tg values decreased from 114 °C to 71.4 °C. The yield strength, Young's modulus and Shore D hardness decreased from 62.9, 2 042 MPa and 80 to 53.4, 1 070 MPa and 72, respectively. The hydrophilicity also decreased. However, the tensile strength and elongation at break were improved appreciably from 36.0 MPa and 46% to 64.5 MPa and 220%, respectively. A new way to prepare Bio-PU with high rigidity and mechanical properties from IS is provided.
2020, 33(4): 382-389.   doi: 10.14133/j.cnki.1008-9357.20191120001
[Abstract](1957) [FullText HTML](353) [PDF 1317KB](5)
Abstract:
Cellulose/sodium alginate (Cellu/SA) composite aerogels were prepared via freeze-drying technique as a valid method to develop 3D scaffolds for tissue engineering. Cellulose with hydroxyl groups showed weak apatite nucleation ability in simulated body fluid(SBF). In order to induce the formation of apatite crystal, oxidation modification of Cellu/SA composite aerogels was carried out with sodium periodate and sodium chlorite. The hydroxyl groups at C2 and C3 of Cellulose and SA were oxidized into carboxyl groups, leading to improve mineralization ability. The morphology and structure were characterized by Fourier Transform Infrared (FT-IR) spectrometer, Scan Electron Microscope (SEM), X-Ray Diffraction (XRD) and X-ray photoelectron spectroscopy. Results show that the formation of HA on the surface of dicarboxylic Cellu/SA composite aerogels is faster with smaller grain size, and the deposition layer is more uniform after mineralization for 7 d. The Cellu/SA composite aerogels thus possess an ultrafine 3D nanoporous network structure. It is noticeable that the dicarboxylic Cellu/SA composite aerogel is a promising candidate for orthopedic biomaterial application with a Ca/P molar ratio of 1.35. In addition, the aerogel has good biocompatibility demonstrated by CCK8 assay and Live/Dead fluorescence staining of L929 cells. The L929 cells activity of both Cellu/SA and dicarboxylic Cellu/SA composite aerogels extracts are higher than 80%. When the culture duration is prolonged to 72 h, an obvious increase in the intensity of green fluorescence is observed, suggesting that the number of cells is increased. The biocompatible mineralized dicarboxylic Cellu/SA composite aerogels can promote cell growth and differentiation and are potential to be applied as a bone repair material.
2020, 33(4): 390-398.   doi: 10.14133/j.cnki.1008-9357.20190520001
[Abstract](3957) [FullText HTML](582) [PDF 1298KB](18)
Abstract:
Quaternized chitosan/nano-zinc oxide (QAC/ZnO) hybrid colloidal particles were prepared by the self-assembly of quaternized chitosan (QAC), L-cysteine (L-cys) and the precursor of nano-zinc oxide Zn(CH3COO)2·2H2O. The chemical composition of QAC/ZnO hybrid colloidal particles was determined by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetic analysis(TG). The morphology and particle size of the hybrid colloidal particles were investigated in detail by means of Zeta potential analyzer, nanoparticle size analyzer and transmission electron microscopy (TEM). The ultraviolet transmittance, oxidation resistance, photocatalytic activity and cytotoxicity of the hybrid colloidal particles were studied by UV-Vis spectroscopy and the in vitro cell experiments. The results show that spherical QAC/ZnO hybrid colloidal particles can be successfully prepared by the self-assembly of QAC, L-cys and the precursor of nano-zinc oxide, and the size of the hybrid colloidal particles can be controlled by the concentration of nano-zinc oxide precursor. QAC/ZnO hybrid colloidal particles have good ultraviolet shielding property, excellent antioxidant property and low cytotoxicity. Moreover, the photocatalytic activity of the QAC/ZnO hybrid colloidal particles are significantly reduced in comparison with ZnO. It is expected to be used in cosmetics as an ultraviolet absorbent.
2020, 33(4): 399-406.   doi: 10.14133/j.cnki.1008-9357.20190512001
[Abstract](4246) [FullText HTML](648) [PDF 1399KB](18)
Abstract:
Poly(D, L-lactide) (PDLLA) with high molecular weight was prepared by ring opening polymerization (ROP) of D, L-lactide. Effects of reaction temperature, reaction time and molar ratio of catalyst to monomer on the molecular weight of PDLLA were investigated through orthogonal synthesis experiments to optimize the polymerization parameters. The number-average molecular weight, chemical structure, thermal properties and mechanical properties of the prepared PDLLA were analyzed by gel chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and universal testing instruments. The degradation properties and cytocompability against fibroblasts (L929) of PDLLA were also evaluated in vitro. The orthogonal experimental results indicated that the optimal parameters for synthesis of high molecular weight PDLLA were that with the molar ratio of catalyst to monomer of 2.04∶5 000, the reaction temperature at 135 °C, and the polymerization time for 4.5 h. Under such conditions, PDLLA with a number–average molecular weight of 2.01×105 was obtained. When the monomer conversion rate was considered in the meantime, the reaction time could be selected as 6.0 h. The obtained PDLLA had a tensile strength of (39.91±1.34) MPa, an elongation at break of 3.94%±0.54%, and an elastic modulus of (1.68±0.34) GPa. The degradation rate increased rapidly after 220 d incubation in phosphate buffer saline (PBS). The PDLLA membrane could promote the proliferation of fibroblasts in vitro, indicating its good cytobiocompatability.
2020, 33(4): 407-414.   doi: 10.14133/j.cnki.1008-9357.20190810001
[Abstract](5590) [FullText HTML](943) [PDF 1278KB](30)
Abstract:
A series of microporous organic polymers (MOPs) were synthesized by a one-step oxidative coupling reaction using carbazole-functionalized siloles, such as 1,1-dimethyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole, 1-methyl-1-phenyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole and 1,1-diphenyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole. The structure and properties of the three MOPs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG) analysis, field emission scanning electron microscope（FSEM） and transmission electron microscope (TEM). FT-IR spectra indicated the success of the oxidative coupling reaction for constructing the polymer frameworks. XRD measurements revealed that all the polymer frameworks were amorphous solid in nature. These MOPs exhibited high thermal stability with the onset of decomposition temperature above 400 ℃ at 5% mass loss under nitrogen flow. The nitrogen adsorption test showed that the specific surface area of the polymers ranged from 587 m2/g to 617 m2/g. There was a rigid main chain and nitrogen-rich conjugate structure of microporous skeleton material. The CO2 adsorption of CPDM-CzS was 2.1 mmol/g (113 kPa, 273 K) and the H2 adsorption of CPPM-CzS was 0.0151 g/g (113 kPa, 77 K）. In addition, CPDM-CzS showed excellent selectivity of adsorption performance of 75.2 for CO2/N2. These microporous frameworks will have prospective applications in gas adsorption and separation.