共聚类吸水树脂综合应用性能研究

以丙烯酸烯丙酯为交联剂合成了丙烯酸和丙烯酰胺共聚类吸水树脂,并对该吸水树脂的综合稳定性（耐热性、耐寒性、耐光性）进行了研究.对树脂凝胶溶胶含量、土壤保水性、树脂对去离子水、生理盐水、人工血、人工尿的吸收能力及树脂的膨胀动力学和热分解动力学作了较为全面的研究.确定了膨胀动力学参数及热分解反应动力学参数, 结果表明：所合成树脂吸水膨胀过程中膨胀指数0.5〈n〈1,属于non-Fikian扩散,吸水树脂的热解过程分为两个阶段,都属于一级反应,以丙烯酸烯丙酯作为交联剂合成的丙烯酸和丙烯酰胺共聚类吸水树脂具有良好的综合应用性能.     

改性聚乙烯醇低温耐水纸制品粘合剂的研制

以盐酸为催化剂,通过甲醛与聚乙烯醇(PVA)反应制得聚乙烯醇缩甲醛(PVF);用三聚氰胺、尿素进行交联,形成尿素-三聚氰胺-甲醛树脂PVFA;然后再分别用乙二醛、氮丙啶进行一步交联得PVFB、PVFC.讨论了不同交联剂的用量和温度对改性PVF的黏度和耐水性的影响.结果表明,当三聚氰胺、尿素、乙二醛及氮丙啶的用量分别为3%、8%、2%及0.2%时制备的交联改性PVA粘合剂达到最佳耐水效果,又能满足低温纸制品生产线要求.     

一些交联聚甲基丙烯酸甲酯材料的热裂—解色—谱质谱分析

本文对５个交联的聚甲基丙烯酸甲酯进行热裂解－色谱－质谱分析研究。裂解温度３７０℃，用ＯＶ－１石英毛细管柱分离，鉴定了交联聚甲基丙烯酸甲酯中少量的共聚单体和助交联剂：甲基丙烯酰胺、氰脲酸三烯丙酯、二甲基丙烯酸－缩二乙二醇酯和二甲基丙烯酸新戊二醇酯。     

新型环氧丙烯酸树脂增韧剂的合成

用马来酸酐和聚乙二醇1000合成具有反应活性端基的聚乙二醇,用红外与核磁共振进行了表征,并用其对环氧丙烯酸树脂进行改性;研究反应温度、反应时间对反应及产物性能的影响;用红外对反应性聚乙二醇和环氧丙烯酸树脂的固化物进行分析.结果表明,反应性聚乙二醇参与了环氧丙烯酸树脂的固化反应,可在交联网络中构成不同长度的柔性链段,显著地提高了环氧丙烯酸树脂的冲击强度.     

丙烯酸酯共聚物乳液自交联反应的研究

本文研究了含环氧基的丙烯酸酯四元共聚物乳液交联后的溶胀度、自交联反应及动力学.结果表明:交联共聚物的溶胀度Q随甲基丙烯酸环氧丙酯单体含量的增加而降低,共聚物在受热的情况下,环氧基因在羧基的作用下开环而发生交联反应,产生网状结构.     

衣康酸酯交联的两性网笼树脂的合成与性能

以大孔强碱树脂为笼树脂,衣康酸酯为交联剂,衣康酸酯和丙烯酸在笼树脂中交联聚合制得两性网笼树脂,考察了衣康酸单酯用量,反应时间,反应温度对树脂吸附量的影响,找出了较好的合成条件.在该条件下两性网笼树脂具有良好的机械性能.     

丙烯酸酯三元共聚物负载硫铂络合物的合成及催化性能

丁二醇二丙烯酸酯、丙烯酸甲酯、丙烯酸β-氯乙酯或丙烯酸ω-氯己酯进行三元共聚,合成了两类4种带ω-氯侧基的交联型聚丙烯酸酯.它们以乙硫醇硫醚化,再与氯亚铂酸钾反应,得到4种交联型聚丙烯酸酯负载的硫铂络合物.这些络合物对癸烯-1、十二烯-1、苯基烯丙醚、苯乙烯与三乙氧基硅烷的硅氢加成反应具有良好的催化活性.讨论了温度、催化剂用量对催化性能的影响及催化剂的重复使用情况.     

钙离子室温交联聚丙烯酸酯无皂水溶胶的研究

研究了Ca^2 聚丙烯酸酯无皂水溶胶交联乳液的制备条件，考察了交联温度、交联剂用量对涂膜性能的影响。结果表明Ca^2 加入无皂水溶胶中的最低温度为40℃，交联反应于室温下即完全发生，交联膜具有较好的耐热、耐水性能。用TEM以及电导滴定对交联机理进行了初步探讨，发现交联反应主要发生在胶乳表面．COO^-与Ca^2 之间。     

含羧基/环氧树脂的丙烯酸酯共聚物乳液的制备与交联(Ⅳ)——混合乳液的制备及其中温交联

研究了含羧基丙烯酸酯乳液和含环氧树脂乳液的混合和交联反应。实验结果表明,混合乳液具有较高的机械稳定性,在室温下可以稳定贮存5个月以上,证实了在叔胺促进剂作用下,交联固化机理为单酯化反应,混合乳液可在中温(<100℃)下固化,涂膜具有优良的物理性能。     

反相悬浮聚合法制备球状卡波树脂的研究

以偶氮二异丁脒盐酸盐(V50)作为引发剂,失水山梨醇硬脂酸酯(Span60)和聚二甲基硅氧烷PEG-7磷酸酯为复合分散剂,蔗糖烯丙基醚和三甲基丙基聚氧乙烯(15)醚三丙烯酸酯为复合交联剂,丙烯酸为单体,正已烷为反应介质,采用反相悬浮聚合方法制备了球状卡波树脂.用光学显微镜和扫描电镜分别对聚合反应的成粒过程和产物的形貌进行了研究.结果表明,聚合体系呈现典型的悬浮聚合相态特征,并获得了堆积密度较高(0.65 g/cm3)的球状卡波树脂.聚合反应动力学研究结果表明,该反相悬浮聚合的聚合速率对单体浓度和引发剂浓度的反应级数分别约为1.36和0.70;聚合反应的表观活化能为78.0 kJ/mol.交联剂对卡波树脂的性能有重要的影响,通过适度交联可提高产物的增稠效率及其抗剪切性能.     

CURING KINETICS AND PROPERTIES OF ACRYLIC RESIN CURED WITH AZIRIDINE CROSSLINKER

A kind of aziridine crosslinkers was synthesized and used to crosslink acrylate copolymers. The crosslinkingproperties and curing kinetics of the resin were studied. It was found that with the increase of the content of crosslinker in theemulsion, the mechanical properties and solvent resistance of the resin will be apparently improved, but its glass transitiontemperature (T_g) is very low. The lowest amount of crosslinker used in the acrylic resin emulsion is 0.25%. Curing kineticsstudied by DSC show that this curing reaction occurs readily because the apparent activation energy of the reaction is low(65.1 kJ/mol). These results demonstrate that the aziridine crosslinker is indeed a low temperature crosslinking agent and canbe used at room temperature.     

Experimental studies and mathematical modeling of the curing reaction of bioinspired copolymers

Polymer curing is a complex process that significantly delineate the final properties of the synthetized material. In this work, the photo-induced crosslinking reaction of synthetic “bio-inspired” copolymers based on thymine and ionic groups was studied by gel permeation chromatography and UV absorption spectroscopy. A mathematical model for the curing process based on statistical techniques and coupled to the kinetics of crosslinking was developed. The model allows to predict both, the evolution of the crosslinking degree as a function of curing time and the gel times as a function of the molecular structure of the copolymer and the curing conditions. The theoretical values showed a very good agreement with the UV–Vis and GPC spectroscopy experimental results for all the copolymers studied. A better knowledge of the curing kinetics of thymine-based biopolymers will enable to develop materials with pre-specified properties and to improve their applications.     

丙烯酸乙酯/烯丙基缩水甘油醚共聚物的热可逆共价交联

研究了双环戊二烯基二羧酸及其铵盐对丙烯酸乙酯 /烯丙基缩水甘油醚共聚物的交联反应 ,对比了二者的交联速度 .用DSC评价了它们的热可逆转化行为 .制得了热可逆部分达 79 7%的共价交联环氧型丙烯酸酯橡胶     

环氧氯丙烷橡胶的热可逆共价交联

以环戊二烯二羧酸钾 [DCPD(COOK) 2 ]为交联剂 ,采用溶液反应法使环氧氯丙烷橡胶 (环氧氯丙烷均聚物 ,CER)交联 ,制得了凝胶含量达 88 75 %的交联CER ,研究了溶剂种类、反应温度、催化剂及交联剂用量对凝胶形成量的影响 .IR谱证明 ,DCPD(COOK) 2 与CER发生双端酯化而交联 ;反应溶解性试验表明 ,该共价交联聚合物具有热可逆转化特性 ,热可逆转化百分率随反应温度的提高、交联剂用量的增多而下降     

Modification of porous poly(styrene-divinylbenzene) beads by friedel-crafts reaction

Summary The influence of Friedel-Crafts reaction on the properties of poly(styrene-divinylbenzene) porous copolymers was studied. Two porous copolymers containing 0.7 and 0.9 mole fractions of divinylbenzene were used for modification. The aim of the process was to increase the copolymer crosslinking. As a crosslinker, tetrachloromethane in the presence of aluminium chloride was used. Reactions were monitored by FTIR and XRF analyses. The main result of the modification process is the change of the copolymer porous structure. Modification also has an influence on the chromatographic properties of the copolymers, especially selectivities.     

Synthesis and properties of flame‐retardant benzoxazines by three approaches

We propose three approaches to obtain flame‐retardant benzoxazines. In the first approach, we synthesize a novel benzoxazine (dopot‐m) from a phosphorus‐containing triphenol (dopotriol), formaldehyde, and methyl amine. Dopot‐m is copolymerized with a commercial benzoxazine [6′,6‐bis(3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazineyl)methane (F‐a)] or diglycidyl ether of bisphenol A (DGEBA). The thermal properties and flame retardancy of the F‐a/dopot‐m copolymers increase with the content of dopot‐m. As for the dopot‐m/DGEBA curing system, the glass‐transition temperature of the dopot‐m/DGEBA copolymer is 252 °C, which is higher than that of poly(dopot‐m). The 5% decomposition temperature of the dopot‐m/DGEBA copolymer increases from 323 to 351 °C because of the higher crosslinking density caused by the reaction of phenolic OH and epoxy. In the second approach, we incorporate the element phosphorus into benzoxazine via the curing reaction of dopotriol and F‐a. After the curing, the thermal properties of the F‐a/dopotriol copolymers are almost the same as those of neat poly(F‐a), and this implies that we can incorporate the flame‐retardant element phosphorus into the polybenzoxazine without sacrificing any thermal properties. In the third approach, we react dopo with electron‐deficient benzoxazine to incorporate the element phosphorus. After the curing, the glass‐transition temperatures of polybenzoxazines decrease slightly with the content of dopo, mainly because of the smaller crosslinking density of the resultant polybenzoxazines. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3454–3468, 2006     

温度对丁腈羟聚氨酯固化反应及性能的影响

端羟基液体丁二烯-丙烯腈共聚物(简称丁腈羟,以HTBN表示)通常用甲苯二异氰酸酯作固化剂,N,N′-二羟丙基苯胺为链延伸剂经二步法固化成丁腈羟聚氨酯弹性体。本文报导丁腈羟-甲苯二异氰酸酯预聚体和N,N′-二羟丙基苯胺体系中同化温度对同化反应及固化弹性体性能的影响规律。     

Acrylamide Hydrogels Preparation via Free Radical Crosslinking Copolymerization: Kinetic Study and Morphological Investigation

The simultaneous gravimetric and dilatometric techniques have been used to study the kinetics of aqueous free radical crosslinking copolymerization of acrylamide (AAm) and N,N^'-methylenebisacrylamide (MBA) at different crosslinker ratios, and reaction temperatures. In this study, the gel properties were investigated using swelling measurements and microscopic techniques. Based on the data, it was proposed that the deviation point of the results of dilatometric technique from those of the gravimetric one can be a new criterion for gel point. The monomer conversion and the equilibrium swelling ratio of the hydrogels were measured as a function of the reaction time. Experimental data showed an inverse dependence of the critical gel point on crosslinker concentration. As the MBA/AAm ratio was decreased to 0.1?wt%, the product appearance changed. In addition, the effects of temperature on the reaction rate and critical gel point were studied. At higher temperatures, the equilibrium swelling ratio reached to its minimum value earlier. Besides, the hydrogel surface became smoother.     

DSC studies on the curing kinetics of chitosan–alanine using glutaraldehyde as crosslinker

The curing of chitosan–alanine with glutaraldehyde as curing agent in the presence of Chlorpheniramine Maleate (CPM) is carried out with the help of differential scanning calorimeter (DSC). The effect of concentration of chitosan and percentage of crosslinker on the curing is studied at a rate of 5 °C/min. Cure kinetics are measured from 30 to 200 °C at four different heating rates (3, 5, 7 and 10 °C/min). It is observed that the crosslinking of chitosan–alanine is an exothermic process which results in a positive peak in the curves. An increase in activation energy (E _α) is observed with extent of conversion.     

Effect of Non-Woven Carbon Nanofiber Mat Presence on Cure Kinetics of Epoxy Nanocomposites

Summary : An investigation was carried out into the cure kinetics of carbon nanofiber (CNF) mat-epoxy nanocomposites, composed of bisphenol-A based epoxy resin and diethylene triamine as a curing agent. It was observed that the rate of cure reaction for CNF mat-epoxy nanocomposites was higher than that for neat epoxy resin at low curing temperatures and the presence of the CNF mat produced the maximum influence at a certain curing temperature and time. At high curing temperature and long curing times, the effect of CNF mat on the cure rate was insignificant. The CNF mat-epoxy composite exhibited somewhat lower value of activation energy than that of the neat epoxy system at the beginning of the curing stage. The weight fraction of CNF mat also affected the cure reaction of epoxy nanocomposites at the same curing temperature. As the amount of CNF mat increased, the cure rate was higher at the same cure time. However, at high CNF mat loading, the cure reaction was retarded since the amount of epoxy and hardener decreased dramatically at high CNF contents together with the hindering effect of the CNF mat on the diffusion of epoxy resin and the curing agent, leading to lower crosslinking efficiency. Although the curing efficiency of epoxy nanocomposites dropped at high CNF mat content, the glass transition temperature (T_g) was still high due to the ultra-high strength of the CNF mat. The cure kinetics of CNF mat-epoxy nanocomposites was in good agreement with Kamal's model.