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Abstract Hydrogels have been prepared from 2-hydroxyethyl methacrylate polymerized in the presence of isocyanate-terminated poly(ethylene glycol) (PEG) crosslinking agents. PEGS of molecular weights 200, 400, and 1000 were investigated. The crosslinked nature of the hydrogels was demonstrated by their insolubility in solvents which normally dissolve poly(HEMA). Hexamethylene diisocyanate (HDI) was mainly used as the isocyanate. The molecular weight of the PEG and the crosslinker content significantly influenced the equilibrium water sorption and mechanical properties of the saturated networks. It was observed that as the molecular weight of the PEG increased, the water sorption increased and the nominal modulus decreased. However, for higher levels of cross-linker, water sorption decreased and modulus increased at low molecular weight PEG; for PEG 1000, water absorption increased as crosslinker content increased. These results are explained by the competing effects of flexibility, crosslink density, and hydrophobicity contributed by the various constituents of the hydrogels. 相似文献
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聚癸二酸丙三醇酯对聚乳酸的改性 总被引:3,自引:0,他引:3
以丙三醇和癸二酸为单体通过熔融缩聚制得了聚癸二酸丙三醇酯(PGS),并用其预聚物(p-PGS)对聚L-丙交酯(PLLA)进行共混改性.利用傅立叶变换红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)及凝胶渗透色谱(GPC)法对P-PGS的结构进行表征,并研究了改性后材料的力学性能、两相相容性、亲水性能和细胞相容性.结果表明:P-PGS具有支化分子结构,分散系数约为2.7;共混改性后的材料弹性模量和拉伸强度均有所下降,而断裂伸长率从7 %显著提高到150%左右;PLLA/PGS属于海岛式共混结构,PGS以小于10μm的尺寸均匀分布在PLLA基体中;共混后材料的亲水性也有一定的提高,且几乎保持了PLLA原有的细胞相容性. 相似文献
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Matthias Rohmer Jan Freudenberg Wolfgang Hubertus Binder 《Macromolecular bioscience》2023,23(4):2200344
The secondary structure of poly(amino acids) is an excellent tool for controlling and understanding the functionality and properties of proteins. In this perspective article the secondary structures of the homopolymers of oligo- and poly-glutamic acid (Glu), aspartic acid (Asp), and α-aminoisobutyric acid (Aib) are discussed. Information on external and internal factors, such as the nature of side groups, interactions with solvents and interactions between chains is reviewed. A special focus is directed on the folding in hybrid-polymers consisting of oligo(amino acids) and synthetic polymers. Being part of the SFB TRR 102 “Polymers under multiple constraints: restricted and controlled molecular order and mobility” this overview is embedded into the cross section of protein fibrillation and supramolecular polymers. As polymer- and amino acid folding is an important step for the utilization and design of future biomolecules these principles guide to a deeper understanding of amyloid fibrillation. 相似文献
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Noboru Ono Chikanori Tsukamura Youta Nomura Syunsuke Hotta Takashi Murashima Takuji Ogawa 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):419-420
New methods for functionalization of conductive poly(thiophenes) and poly(pyrroles) using fused aromatics or crown ethers are discussed. 相似文献
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Patrícia P. C. Sartoratto I. Valria P. Yoshida 《Journal of polymer science. Part A, Polymer chemistry》1992,30(11):2333-2340
In this work several polyorganosilylenes were synthesized including homo-and copolymers containing SiMe2 and SiPh2 units. A Wurtz-type coupling reaction of the respective dichlorodiorganosilanes with sodium metal, varying the Ph2SiCl2/Me2SiCl2 ratio was the chosen synthesis method. Products with different characteristics for solubility, structure (cyclic or linear), composition, and molecular weight distribution could be obtained depending on the comonomer ratios employed. The polysilane derivatives were characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance (1H-NMR), and gel permeation chromatography (GPC). Valuable information related to the comonomers' reactivities was obtained, such as molecular weight distribution, composition, and relationships between yields of soluble, insoluble, and cyclic materials of each polycondensation reaction. © 1992 John Wiley & Sons, Inc. 相似文献
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分别以氨基聚乙二醇和氨基聚乙二醇单甲醚为大分子引发剂,采用开环聚合的方法合成了两亲性聚L-丙氨酸-聚乙二醇(PAE)和聚L-丙氨酸-聚乙二醇单甲醚(PAME)两种嵌段共聚物,其结构经1H NMR,IR,DSC,GPC等表征;利用园二色技术研究了其在水溶液中的二级结构,用芘荧光探针技术研究了其胶束的形成及其临界胶束浓度(CMC),利用透射电镜研究了胶束的形态。结果表明,在水溶液中共聚物链以α-螺旋构象形式存在,在一定条件下嵌段共聚物PAE-1,PAE-2,PAME-1和PAME-2能够形成球形的稳定胶束,PAE-1形成胶束的CMC为3.36×10-5mol.L-1,CMC值受嵌段类型和共聚物中聚L-丙氨酸链段含量的影响。 相似文献
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Edward N. Peters 《高分子科学杂志,C辑:聚合物评论》2013,53(2):173-208
The need for elastomeric polymers which will maintain their elastic properties at high temperatures has led to a wide interest in inorganic-based polymers [l]. The development of carborane-siloxane polymers in the early 1960s was a breakthrough in the search for a high-temperature elastomer. Incorporation of a carborane moiety into the siloxane backbone significantly enhanced the overall thermal stability [2]. 相似文献
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Tanaka S Fujiwara S Tanaka H Taniguchi M Tabata H Fukui K Kawai T 《Chemical communications (Cambridge, England)》2002,(20):2330-2331
Poly(dA).Poly(dT) molecules up to 1000 base pairs (bp) have been synthesized using enzymatic reaction, and characterization by STM observation shows that the DNA has no defects in the duplex structure. 相似文献
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聚L-丙氨酸-聚乙二醇嵌段共聚物的胶束化行为研究 总被引:5,自引:3,他引:5
以氨基聚乙二醇单甲醚(MPEG-NH2)为大分子引发剂, 采用开环聚合方法合成了聚L-丙氨酸-聚乙二醇嵌段共聚物(PAME), 并对其结构进行了表征; 用圆二色谱(CD)研究了嵌段共聚物在水溶液中的二级结构, 用芘荧光探针技术研究了共聚物胶束的形成及其临界胶束浓度(CMC), 利用动态光散射(DLS)和透射电镜(TEM)研究了胶束的粒径分布和形态. 结果表明, 在水溶液中共聚物链以α-螺旋构象形式存在, 在一定条件下嵌段共聚物能够形成球形的稳定胶束, PAME-1形成胶束的CMC为1.99×10-5 mol/L, CMC值受共聚物中聚L-丙氨酸(PLA)链段含量的影响. 相似文献
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Ohne Zusammenfassung 相似文献
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Poly(methacrylonitrile-co-styrene) (PMANS) and Poly(acrylo-nitrile- co- styrene) (PANS) having 1:1 composition were prepared with free-radical initiators. The polymers were fractionated into fractions having narrow molecular weight distribution. The dilute solution properties of the fractionated copolymers were studied by light scattering, viscometry, and osmometry in solvents (methyl ethyl ketone, dimethylformamide, and acetone), [n]-M w and(r2)w l/2?M w relationships have been established. The validity of the various graphical methods for the determination of Flory′s constant, K θ were observed. From the values of the steric factors it was noticed that the copolymer coil of PANS is stiffer than that of PMANS. 相似文献
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A series of multiblock poly(ether urethane)s comprising poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized. Their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 8 to 12 wt%. The composition and structural information of the copolymers were studied by GPC and 1H NMR. The critical micellization concentration (CMC) and thermodynamic parameters for micelle formation were determined at different temperatures. The temperature response of the copolymer solutions were studied and found to be associated with the composition of the copolymers. 相似文献
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利用可控微乳液法合成粒径19~200 nm,且呈球状分布均匀的聚甲基丙烯酸甲酯/聚(异戊二烯-co-苯乙烯)(PMMA/PIS)核壳纳米粒子,通过水合肼产生原位氢的技术,对合成的PMMA/PIS乳液体系进行直接常压氢化,对影响氢化度的因素、聚合物氢化前后结构、热性能进行了研究.结果显示,聚合物粒径、水合肼及双氧水用量等都是影响聚合物的氢化度的因素.研究发现,氢化以PMMA为核,PIS为壳的核壳结构乳液可以显著提高PIS氢化程度,减少氢化过程中凝胶产生.利用FTIR、~1H-NMR、Na_2S_2O_3滴定法测定了乳液的氢化度.结果表明,当聚合物粒径小于200 nm时,乳液氢化度可达到95%以上,且无凝胶现象产生.GPC结果证明了反应是氢化而非凝胶过程.利用TEM、DLS测试了氢化后乳液的核壳结构和粒径.实验结果显示,PMMA/HPIS为核壳纳米结构.TGA结果显示,当氢化度为98%时,聚合物耐热性提高41°C. 相似文献