丙烯酸接枝壳聚糖水凝胶的制备及其pH敏感性

利用迈克尔加成反应制备了两性聚电解质物质-丙烯酸接枝壳聚糖(ACS),利用FTIR和1HNMR对ACS进行结构表征,制备了丙烯酸接枝壳聚糖水凝胶(ACSG),并研究其pH敏感性和溶胀行为.结果如下:通过迈克尔加成反应,在壳聚糖分子链上引入了羧乙基基团;ACSG在pH值1.2～9.0溶液中均有较强的pH敏感性,酸敏,性优于碱敏性;ACSG在不同pH值溶液中的溶胀行为各不相同,在偏酸和偏碱性时溶胀度较大,pH值5.0时溶胀度最小;随着交联荆用量的增加,ACSG的溶胀度逐渐降低;随着取代度的增大,ACSG的溶胀度则先增大后减小.     

天然高分子亲水性凝胶材料在竹醋液中 溶胀度的初步研究

测定了壳聚糖、黄原胶、海藻酸钠3种天然高分子亲水性凝胶材料在竹醋液中的溶胀度。探讨了温度、pH值对其溶胀度和溶胀速率的影响。结果表明在20~40℃ 范围内,3种凝胶的溶胀度和溶胀速率随着温度的升高而增加;在不同pH值的竹醋液中,壳聚糖和黄原胶的溶胀速率十分相近,而且黄原胶比壳聚糖更稳定。     

温度和pH值对智能水凝胶溶胀行为的影响

以N-马来酰化壳聚糖(N-MACH)为交联剂,N-异丙基丙烯酰胺(NIPAAm)为单体,羧甲基纤维素钠(CMC)为半互穿材料,分别合成了PNIPAAm和PNIPAAm/CMC半互穿网络智能水凝胶,研究了两种水凝胶在不同温度的去离子水和不同pH值的缓冲溶液中的溶胀现象,结果表明介质温度和pH值对水凝胶的溶胀行为有显著影响。在温度和pH值一定时,水凝胶的溶胀率随着交联剂用量的增加而下降,随着CMC用量的增加而上升。     

新型pH敏感性壳聚糖/明胶水凝胶的制备及其性能

用天然多糖壳聚糖和明胶制备了具有pH敏感性的壳聚糖/明胶水凝胶,研究了pH值对于该凝胶溶胀度的影响,采用红外光谱和电镜扫描对其结构进行了表征。结果表明,水凝胶在碱性和酸性环境中均具有pH敏感性,在酸性溶液中凝胶的溶胀比远大于碱性溶液中的溶胀比,其在pH值3.0时的溶胀度最大,在pH值9.0时的溶胀度最小,且其在不同pH 溶液中重复可逆溶胀收缩。同时,随着交联剂用量的增大,水凝胶的溶胀度减小。     

HPMC水凝胶溶胀性能的影响因素研究

制备了一系列具有不同相对分子质量和取代度的羟丙基甲基纤维素(HPMC)水凝胶,并用称重的方法对凝胶的溶胀性能进行了研究,考察了温度、pH值、溶剂类型、取代度和相对分子质量对HPMC水凝胶溶胀性能的影响。结果显示,HPMC水凝胶的平衡溶胀度随温度的升高而减小;其溶胀行为受溶剂影响显著,而受溶液pH值的影响不明显;而取代度和相对分子质量都对凝胶溶胀行为有较大的影响。     

pH响应PAAm-g-PEG/PVP半互穿网络水凝胶的制备以及溶胀动力学

采用硝酸铈胺-聚乙二醇为氧化-还原引发体系,N,N-亚甲基双丙烯酰(N,N-MBA)为交联剂,通过简单的自由基聚合法,设计合成了一种聚(丙烯酰胺-g-聚乙二醇)/聚乙烯吡咯烷酮PAAm-g-PEG/PVP接枝交联结构的半互穿网络水凝胶。研究了它们在不同pH值缓冲溶液中的溶胀与扩散行为以及溶胀动力学;并采用红外光谱和热分析系统对其结构和热性能进行了分析测量。实验结果表明:水凝胶的溶胀行为和扩散模式取决于溶液的pH值。随着缓冲溶液pH值增加,平衡溶胀率减小;在不同的缓冲溶液中理论最大吸水量S∞与实验值基本相一致。水凝胶的溶胀行为可以通过选择加入不同分子量大小的PEG来调节和控制。     

富间规立构聚乙烯醇水凝胶的应用

用pH值为4.0、7.4和9.0的缓冲溶液（BS）在0℃制备了3种物理交联的富间规立构的聚乙烯醇（s-PVA）水凝胶。将这些凝胶浸入到温度高于0 ℃的相同BS中，这些凝胶先是溶胀后，再开始收缩12小时，分别在27℃，37℃和47℃以亮蓝从圆柱状凝胶中的释出进行了研究，该凝胶是用pH率承温度上升而加快。亮蓝释出的主要因素不在于凝胶的收缩，而在于溶胀，因为溶胀度（DS）随温度从27℃、37℃、47℃的上升而变大。从凝胶（pH=4.0)中释出的速率大于从pH为7.4的凝胶中的释出速率，这是因为早在pH为4.0时水凝胶的DS就已经增大了，在pH为7.4时从最初的60%的分级释出所求得的这些释出的表观扩散指数不大于0.45，这是因为在释出期间有了溶胀，pH为4.0时的指数为0.45，是因为即刻产生了溶胀，在不同的温度下对无规立构PVA(α-PVA)水凝胶断-续的收缩行为进行了观察。在5℃时亮蓝的释出速率低于在27℃的情况，在5℃时经过一次断-续循环后看不出有什么变化。     

聚氨酯／聚苯乙烯互穿聚合物网络的结构与性能研究

通过改变组分比研究了PU/PS IPN结构与性能变化的规律。结果表明,在PU/PS为70/30时,电镜照片上呈现精细的细胞结构,相区尽寸缩小,网络间互穿程度最高,且溶胀度最低。热力学性能也同时出现最佳值,     

果胶-g-聚(丙烯酸-co-丙烯酰胺)水凝胶溶胀性能研究

在水溶液中通过接枝共聚法制备出果胶-g-聚(丙烯酸-co-丙烯酰胺)水凝胶(PECAA),研究了PECAA在蒸馏水中的溶胀动力学,考察了其在不同溶剂中的溶胀行为。结果表明,PECAA在蒸馏水中的溶胀动力学过程可分为3个阶段;以PECAA在蒸馏水中的饱和溶胀度为参照值,其在自来水中的饱和溶胀度比值最高,其次为NaCl溶液,在CuSO4溶液中的饱和溶胀度比值最低。     

粒状温敏性水凝胶的溶胀行为

研究了具有温敏性的PNIPA粒状水凝胶在不同水溶液中的溶胀过程。考察了水溶液的离子强度、pH值、温度以及凝胶组成等因素对水凝胶溶胀速率和倍率的影响。研究发现,粒状PNIPA水凝胶粒子的溶胀很快,在1到2分钟内就能达到溶胀平衡。温度和凝胶的交联度是影响溶胀速率的主要因素。由于溶质改变了网络的亲水性或离子基团的作用强度,使得凝胶的溶胀速率和倍率也相应发生变化。     

Investigation on the microstructure and the electric property of poly(propylene)/chlorinated poly(propylene)/poly(aniline) composites

The article presents results of studies on composites made from poly(propylene) (PP) modified with poly(aniline) (PANI) doped with dodecylbenzene sulfonic acid (DBSA) and chlorinated poly(propylene) (CPP). The volume resistivity of PP/CPP/PANI composites was detected, and the results show that the volume resistivity decreases with increasing CPP content, and there exists a minimum volume resistivity. Effects of CPP on the microstructure and crystalline structure of the PP/CPP/PANI composites and the relationship between the effects and the electric property were carefully analyzed by scanning electron microscope (SEM) and wide angle X‐ray diffraction (WAXD). The method that the specimens of SEM are polished is appropriate to investigate the morphology of conducting polymer composites. The obtained results illuminate that the area of conducting parts and insulating parts obtained from the digital analysis of the SEM image is obviously influenced by the CPP content, the parameters of the lamellar‐like structure are immediately related to CPP content and denote the dispersion of PANI‐DBSA, and the percent crystallinity and mean crystal size of PP are directly correlated with the CPP content. The increasing area of conducting parts, the increasement of layer distance, the decreasement of size and layer number of the lamellar‐like structure of PANI‐DBSA, and the increasement of the percent crystallinity and mean crystal size of PP are beneficial to the improvement of the conductive property of PP/CPP/PANI composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of poly(pyridylurea) and poly(pyridylthiourea), potentially semiconducting polymers

Poly(pyridylureas) and poly(pyridylthioureas) were synthesized by reacting 2,6‐diaminopyridine with phosgene and thiophosgene, respectively, using THF and pyridine as solvent. The synthesized polymers were characterized by IR‐spectroscopy, elemental analysis, and X‐ray photoelectron spectroscopy. Thermal stability of the polymers was determined by thermal degradation between 35°C and 700°C. The 50% weight loss of polypyridylureas was above 400°C while for the polypyridylthioureas it was above 450°C. Undoped poly(pyridylureas) and poly(pyridylthioureas) behave as semiconductors, σ = 10^?9 (Ω cm)^?1. After doping with I₂ and SbF₅, the electrical conductivity increases several orders of magnitude, σ = 10^?7(Ω cm)^?1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

High molecular weight poly( -lactide) and poly(ethylene oxide) blends: thermal characterization and physical properties

The miscibility of high molecular weight poly( -lactide) PLLA with high molecular weight poly(ethylene oxide) PEO was studied by differential scanning calorimetry. All blends containing up to 50 weight% PEO showed single glass transition temperatures. The PLLA and PEO melting temperatures were found to decrease on blending, the equilibrium melting points of PLLA in these blends decreased with increasing PEO fractions. These results suggest the miscibility of PLLA and PEO in the amorphous phase. Mechanical properties of blends with up to 20 weight% PEO were also studied. Changes in mechanical properties were small in blends with less than 10 weight% PEO. At higher PEO concentrations the materials became very flexible, an elongation at break of more than 500% was observed for a blend with 20 weight% PEO. Hydrolytic degradation up to 30 days of the blends showed only a small variation in tensile strength at PEO concentrations less than 15 weight%. As a result of the increased hydrophilicity, however, the blends swelled. Mass loss upon degradation was attributed to partial dissolution of the PEO fraction and to an increased rate of degradation of the PLLA fraction. Significant differences in degradation behaviour between PLLA/PEO blends and (PLLA/PEO/PLLA) triblock-copolymers were observed.     

聚甲基氢硅烷及其共聚物的合成及发光性能的研究

以甲基二氯硅烷,二甲基二氯硅烷,二苯基二氯硅烷及甲基乙烯基二氯硅烷为原料,采用钠缩合法合成了聚甲基氢硅烷及聚甲基氢硅烷与聚二甲基硅烷,聚二苯基硅烷和聚甲基乙烯基硅烷的共聚物,并用IR,UV,1HNMR,GPC进行了表征。     

Binary blends based on poly(N‐isopropylacrylamide): Miscibility studies with PVA,PVP, and PAA

Blends of poly(vinyl alcohol) (PVA), poly(acrylic acid), (PAA), and poly(vinyl pyrrolidone) (PVP), with poly(N‐isopropylacrylamide) (PNIPAM), were prepared by casting from aqueous solutions. Mechanical properties of PNIPAM/PVA blends were analyzed by stress–strain tests. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were employed to analyze the miscibility between the polymeric pairs. The results revealed that PNIPAM is not miscible with PVA and PVP in the whole range of composition. On the other hand, PNIPAM interacts strongly with PAA forming interpolymer complex due to the formation of cooperative hydrogen bonds. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 743–748, 2004     

The substituent effects on the structure and surface morphology of polyaniline

In this work, poly(2‐fluoroaniline), poly(2‐chloroaniline), poly(2‐methylaniline), and poly(N‐ethylaniline) were prepared by a self‐assembly method using an oxidizing system consisting of a dopant anion, p‐toluene sulfonate with ammonium peroxydisulfate. The effects of substituents on the surface morphology, conductivity, molecular weight, spectral and thermal properties of the polymers were studied. SEM results revealed that the surface morphology of the resulting polymers changed from nanofiber to spherical structure by changing the substituent on the aniline monomers. The structure and properties of these conducting films were characterized by FTIR, UV‐vis, elemental analysis, TGA, conductivity, and cyclic voltammetry. The polymer films show electroactivity in monomer free solution. Molecular weight of the polymers was determined by gel permeation chromatography. The dry electrical conductivity values of the substituted‐polyanilines were found to be lower than that of PANI. The results revealed that the molecular structures of the polymers were similar to those of the emeraldine form of polyaniline. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Melting,crystallization behaviors,and nonisothermal crystallization kinetics of PET/PTT/PBT ternary blends

The melting, crystallization behaviors, and nonisothermal crystallization kinetics of the ternary blends composed of poly(ethylene terephthalate), poly(trimethylene terephthalate) (PTT) and poly(buthylene terephthalate) (PBT) were studied with differential scanning calorimeter (DSC). PBT content in all ternary blends was settled invariably to be one‐third, which improved the melt‐crystallization temperature of the ternary blends. All of the blend compositions in amorphous state were miscible as evidenced by a single, composition‐dependent glass transition temperature (T_g) observed in DSC curves. DSC melting thermograms of different blends showed different multiple melting and crystallization peaks because of their various polymer contents. During melt‐crystallization process, three components in blends crystallized simultaneously to form mixed crystals or separated crystals depending upon their content ratio. The Avrami equation modified by Jeziorny and the Ozawa theory were employed to describe the nonisothermal crystallization process of two selected ternary blends. The results spoke that the Avrami equation was successful in describing the nonisothermal crystallization process of the ternary blends. The values of the t_1/2 and the parameters Z_c showed that the crystallization rate of the ternary blends with more poly(ethylene terephthalate) content was faster than that with the lesser one at a given cooling rate. The crystal morphology of the five ternary blends investigated by polarized optical microscopy (POM) showed different size and distortional Maltese crosses or light spots when the PTT or poly(ethylene terephthalate) component varied, suggesting that the more the PTT content, the larger crystallites formed in ternary blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

导电聚合物PEDOT/PSS-MPEG的制备及性能

引言导电高分子既有导体材料的光电学特性,又有良好的力学性能和可加工性[1],这使得导电高分子材料具有广泛的应用前景。聚噻吩类有机导电材料[2]就是这类材料中的一种。聚噻吩的室温电导率     

Swelling and electroresponsive characteristics of interpenetrating polymer network hydrogels

Electroactive polymer gels composed of poly(diallyldimethylammonium chloride), poly(acrylic acid) and poly(vinyl alcohol) were prepared and their swelling properties characterized. The swelling behavior of the polymer gels was studied by immersion of the gels into deionized water at room temperature. The state of the water in the polymer gels was characterized using differential scanning calorimetry and the microstructure of the swollen gel in each sample was investigated using scanning electron microscopy. The samples' response to being stimulated in an applied electric field was also investigated. Copyright © 2005 Society of Chemical Industry     

An inelastic electron tunnelling spectroscopy (IETS) study of poly(vinylacetate) poly(methyl methacrylate) and poly(vinylalcohol) adsorbed on aluminium oxide

IETS is used to investigate the adsorption of poly(vinylacetate) (PVA), poly(methylmethacrylate) (PMMA), and poly(vinylalcohol) (PVOH) on aluminium oxide. These polymers are of interest in the field of adhesion science, and until now synthetic macromolecules have not been studied in this way. Both commercially available polymers and those synthesized in our laboratory have been used. On the basis of IET spectra presented here, and existing i.r. spectra it is believed that PMMA and PVA undergo ester cleavage at the oxide surface leading to their subsequent adsorption. For PMMA this is thought to be via carboxylate anions generated on the polymer side groups, while PVA is expected to be adsorbed as PVOH. Bonding of PVOH to the oxide is not fully understood, but may occur by the formation of an AlOC bridge. Another possibility for the above polymers, that of intermolecular hydrogen bonding between polar polymer side groups, and adsorbed hydroxyl species present on the oxide surface, cannot be ruled out.