Preparation and characterization of novel semi‐interpenetrating 2‐hydroxyethyl methacrylate‐g‐chitosan copolymeric microspheres for sustained release of indomethacin

A novel semi‐interpenetrating (semi‐IPN) graft copolymer of 2‐hydroxyethyl methacrylate (HEMA) with chitosan (CS) has been prepared in the form of microspheres, using water‐in‐oil (W/O) emulsion technique. Microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X‐ray diffractometry (X‐RD) to confirm the crosslinking and polymorphism of indomethacin (IDM). The X‐RD and DSC techniques indicated a molecular‐level dispersion of IDM in the IPN matrix. Scanning electron micrographs (SEM) taken at the cross section of the microspheres have shown rough surfaces around the microspheres. The sustained release characteristics of the matrices for IDM, an anti‐inflammatory drug, were investigated in pH 7.4 media. Particle size and size distribution of the microspheres were studied by laser light diffraction particle size analyzer. The drug was released in a sustained manner for up to 12 h. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Preparation and characterizations of interpenetrating polymer network hydrogels of poly(ethylene oxide) and poly(methyl methacrylate)

Interpenetrating polymer network (IPN) hydrogels based on poly(ethylene oxide) and poly(methyl methacrylate) were prepared by radical polymerization using 2,2‐dimethyl‐2‐phenylacetophenone and ethylene glycol dimethacrylate as initiators and crosslinkers, respectively. The IPN hydrogels were analyzed for sorption behavior at 25°C and at a relative humidity of 95% using dynamic vapor sorption. The IPN hydrogels exhibited a relatively high equilibrium water content in the range of 13–68%. The state of water in the swollen IPN hydrogels was investigated using differential scanning calorimetry. The free water in the hydrogels increased as the hydrophilic content increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 258–262, 2003     

Effects of NCO/OH molar ratio on miscibility and properties of semiinterpenetrating polymer networks from polyurethane and benzyl konjac glucomannan

Semi‐interpenetrating polymer network (semi‐IPN) films with different NCO/OH molar ratios of the urethane prepolymer, coded as UB, were prepared from polyurethane (PU) and benzyl konjac glucomannan (B‐KGM) by a casting method. The effect of the NCO/OH molar ratio of the urethane prepolymer on the miscibility and properties of the UB films was investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, thermogravimetric analysis, and swelling and tensile tests. The results indicated that, with an increase of the NCO/OH ratio, the crosslink density of the UB films increased, resulting in improved miscibility between PU and B‐KGM and a relatively high light transmittance of the UB films. However, the thermal stability of the UB films decreased with increase of the NCO/OH ratio of the urethane prepolymer, due to the depolymerization of the urethane bonds of the PU networks. When the NCO/OH ratio increased from 2 to 4, the tensile strength of the UB films increased from 15 to 27 MPa, while the breaking elongation decreased from 72 to 16%, resulting from the chemical and physical crosslinks, namely, the enhancement of the covalent bonds and hydrogen‐bonding networks. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1304–1310, 2003     

Properties and pervaporation separation of hydroxyl‐terminated polybutadiene‐based polyurethane/poly(methyl metharcylate) interpenetrating networks membranes

Hydroxyl‐terminated polybutadiene (HTPB), 4,4′‐dicyclohexyl methane diiscyanate (H₁₂MDI), and 1,4‐butane diol are used to synthesize polyurethane (PU) solutions by two‐stage process. Interpenetrating networks (IPNs) of HTPB‐based PU and poly(methyl methacrylate) (PMMA) with HTPB/MMA (wt/wt % ratio) = 2.0, 1.5, 1.0, 1.5, 0.8, and 0.6, which are designated as IPN1 to IPN5, respectively, are synthesized by sequential polymerization technique. Thermal properties, tensile strength, and contact angle of membranes increase with the increase of MMA content, while the elongation of membranes show the reverse trend. Characterization of membranes are investigated by C?C/C?O absorption ratio and infrared absorption frequency shiftment. These PU and IPN membranes are used for the separation of ethanol/water and isopropanol/water solution by pervaporation test. IPN3 membrane possesses the largest pervaporation permeability and the separation factor. The pervaporation results of ethanol/water feed has the same trend as that of isopropyl alcohol (IPA)/water solution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

热塑性IPN PP/PA6的力学性能研究

利用热塑性IPN技术制备PP／PA6共混物，通过方差分析讨论了PP含量、溶胀温度、溶胀时间对热塑性IPN PP／PA6共混材料力学性能的影响，利用红外光谱仪对共混材料PP／PA6的结构进行表征同时利用扫描电镜对PP和热塑性IPN PP／PA6的断口形貌进行观察，发现利用热塑性IPN技术来制备的PP／PA6共混物中PP与PA6之间具有一定的相容性。     

MDI聚氨酯/聚硅氧烷IPN的结构与力学性能

用MDI聚醚氨酯和含少量苯基的聚二甲基硅氧烷合成了一系列的聚氨酯／聚硅氧烷IPN阻尼弹性体，研究了材料的结构与力学性能．结果表明，当聚氨酯与聚硅氧烷的质量比为90：10时。IPN的抗张强度达41．57MPa，断裂伸长率为376％，并具有良好的阻尼性能，玻璃化转变温度范围大于80℃．聚氨酯／聚硅氧烷IPN具有细微的微相分离结构，聚硅氧烷在IPN中的微相尺寸为微米级，并趋向于分布在IPN的表面．     

聚氨酯/聚丙烯酸酯互穿网络涂料印花粘合剂的制备和应用

本文综述了聚氨酯/聚丙烯酸酯互穿网络(IPN)涂料印花粘合剂。介绍了IPN粘合剂的制备方法及其不同配比时对拉伸强度、断裂伸长率、摩擦牢度性能的影响。IPN粘合剂可克服聚丙烯酸酯粘合剂的延伸性差、湿摩擦牢度低、易吸尘和粘搭性强的缺点,是改进聚丙烯酸酯类粘合剂性能十分有效的方法。     

超支化聚酯/端羟基聚丁二烯型聚氨酯互穿网络的固化动力学

通过傅立叶红外光谱,在不同温度下测试了端羟基聚丁二烯(HTPB)型聚氨酯和含有20 %(质量分数)第4代超支化聚酯的HTPB型聚氨酯的固化过程,探索了超支化聚酯的加入对异氰酸酯(NCO)与OH之间反应的影响.结果表明:超支化聚酯的加入对NCO与OH之间的反应有很大的促进作用,反应的活化能由28.3 kJ/mol降低到18.3 kJ/mol,反应均为二级动力学反应.     

PZT-IPN阻尼材料的研究进展

阻尼材料广泛应用于交通工具、产业机械、建筑土木、家用电器、精密仪器和军事装备等领域。科学技术的不断发展,对阻尼材料的要求不断提高。本文主要综述了聚合物基压电智能阻尼材料的阻尼机理。并详细分析介绍了聚合物基IPN压电阻尼材料的设计原理及阻尼效果。     

互穿网络敏感型聚氨酯水凝胶的合成与研究

以异佛尔酮二异氰酸酯（IPDI）、聚氧化丙烯二醇（PPG-220）、二羟甲基丙酸（DMPA）、蓖麻油（C0）等为主要原料,合成交联型水性聚氨酯乳液,在此乳液中加入丙烯酰胺、引发剂（KPS）,交联剂（BMA）进行自由基聚合,制备具有IPN结构的聚氨酯-聚丙烯酰胺（PU—PAAm）水凝胶。研究了（PU—PAAm）水凝胶溶胀率（SR）受pH值、温度（T）、交联剂用量等因素的影响。