一些热塑改性热固性树脂体系结构对反应诱导相分离时间/温度依赖性的影响

利用光学显微镜、DSC等手段研究了一些上临界共溶温度(UCST)类型的热塑性改性热固性树脂体系反应诱导相分离时间/温度依赖性随组分化学结构的变化规律.结果表明,分相活化能Ea(ps)受热塑性树脂的主链结构、热固性单体、交联剂结构、化学计量比等因素的影响.利用相互作用能密度解释了实验所研究的UCST体系的相分离活化能Ea(ps)随组分结构的变化规律.     

环氧树脂在热塑性树脂改性中的应用

本文综述了国内外有关利用环氧树脂改性热塑性树脂共混体系研究的最新进展。着重阐述了环氧树脂在热塑性树脂之间的增容作用,如尼龙6(PA6)合金体系,改性聚苯乙烯塑料(ABS)合金体系,以及聚对苯二甲酸丙二醇酯(PTT)合金体系等。同时,介绍了利用环氧树脂的反应活性提高无机填料在聚合物中分散性研究的情况,如二氧化硅纳米粒子在聚醚砜(PES)中,以及滑石粉在聚丙烯(PP)中分散性的提高。最后,简介了环氧树脂改性热塑性树脂提高热塑性树脂物理机械性能方面的研究方向和成果并展望了环氧树脂在热塑性树脂改性研究中的前景。     

热固性树脂韧性的改进途径及其增韧机理

本文系统地综述了加入无机填料、弹性体及热塑性塑料;与热塑性塑料形成半IPN(Semi-Interpenetruting Polymer Network);改变交联网的化学结构;控制分子交联状态的不均匀性等增加热固性树脂韧性的途径。并对以上几种增韧途径的机理及其橡胶改性体系相分离的热力学和动力学判据也进行了讨论。     

反应诱导相分离法制备双马来酰亚胺树脂微球

从聚醚酰亚胺(PEI)/[双马来酰亚胺(BMI)单体+烯丙基双酚A(DBA)]共混体系出发,通过反应诱导相分离,制备了约3μm尺寸的、单分散的BMI树脂微球.用扫描电镜(SEM)观察BMI树脂微球的形态,用激光粒度仪(LPS)表征BMI树脂微球的粒度及其分布,差示扫描量热法(DSC)测试BMI树脂微球的Tg.研究结果表明:PEI和聚酯酰亚胺(PEsI)的主链结构对BMI树脂微球形态有很大影响;PEI-A的用量增加,BMI树脂微球粒径减小,且粒度分布呈不均匀-均匀-不均匀变化;BMI树脂微球的Tg为215~218℃,略低于纯BMI树脂的Tg(225℃).     

氰酸酯树脂改性热固性丁苯树脂的固化及其动力学

利用傅里叶变换红外光谱法(FT-IR)和差示扫描量热法(DSC)研究了氰酸酯树脂改性热固性丁苯树脂的固化反应特性及其动力学.以温度-升温速率外推法计算得到固化反应起始温度(Ti0)、峰顶温度(Tp0)和终止温度(Tf0)分别为414.2、444.5、460.6 K,对改性树脂的固化过程进行优化.采用Freeman-Ca...     

新型γ-聚谷氨酸吸水树脂的合成

以γ-聚谷氨酸(γ-PGA)为原料,乙二醇缩水甘油醚为交联剂,采用溶液聚合法合成了新型γ-PGA吸水树脂(1),其结构经IR表征.研究了反应体系的pH,反应温度和反应时间对1吸水率和透光率的影响.结果表明,在反应体系pH 4.3,于70℃反应36 h的最佳反应条件下合成1,吸水率220 g·g-1,透光率99.6％,分解温度334.9℃.     

动态扭振法在树脂固化研究中的最新应用

用计算机全自动控制的LHX-Ⅱ型树脂固化仪对热固性树脂基蒙脱土纳米复合材料、热塑性树脂PMMA基蒙脱土纳米复合材料以及聚合物互穿网络等体系进行了固化反应的研究。借用Avrami理论来处理树脂基纳米复合材料的固化行为,求取固化反应表现动力学参数。     

超支化树脂改性UV固化粉末涂料

本文将超支化树脂(HBP)与UV固化粉末涂料相结合,研究了超支化树脂对该涂料的树脂体系玻璃化温度、流变性能及涂膜各项物理性能的影响.结果表明:添加改性与未改性超支化树脂都能降低树脂体系的玻璃化温度,改性超支化树脂不影响体系的流变性能及涂膜性能,未改性超支化树脂可以降低体系粘度但使涂膜性能变差.     

丙烯酸树脂／蒙脱土纳米复合材料的制备研究

采用离子交换法,用十六烷基三甲基溴化铵对钠基蒙脱土(Na-MMT)进行改性制备了有机蒙脱土(OMMT).用丙烯酸(AA)、硫酸化蓖麻油、乳化剂OP-10、过硫酸钾为原料进行水溶液聚合制得丙烯酸树脂.将丙烯酸树脂与改性蒙脱土通过聚合插层制备了丙烯酸树脂/ 蒙脱土纳米复合材料.通过傅立叶变换红外(FTIR)和X-射线衍射 (XRD)等手段对复合材料的结构进行了表征,结果表明:丙烯酸树脂插层进入有机蒙脱土内可形成插层型或剥离型的纳米复合材料.蒙脱土含量及蒙脱土与丙烯酸树脂的反应温度、反应时间均对复合材料的剥离行为产生影响,在蒙脱土含量为树脂固含量的7%、温度为70℃、反应4h的条件下可得到完全剥离的纳米复合材料.     

乙炔基封端聚酰亚胺增韧改性的相结构

以双酚A二醚二酐(BPADA)和3乙-炔苯胺(APA)为原料,通过两步法合成一种热固性可交联的聚酰亚胺预聚体.将此预聚体分别与不同结构的热塑性聚酰亚胺(PI)共混,对其进行增韧改性,通过调控热塑性聚酰亚胺的质量分数,引入结构相似且含有更多柔性基团的热塑性聚酰亚胺(如含有醚键和对称甲基结构的二酐),得到了热固/热塑性聚酰亚胺复合膜.利用差示扫描量热仪(DSC)及扫描电镜(SEM)对该体系的相分离结构和相容性进行研究,并讨论其机械性能和热性能.结果表明,相分离结构使体系的机械性能得到改善,同时也保持了原有的优异热性能.     

Phase separation time/temperature dependence of some thermoplastics-modified thermosetting systems

The phase separation processes of various thermoplastics-modified thermosetting systems which show upper critical solution temperature (UCST) or lower critical solution temperature (LCST) were studied with emphasis on the temperature dependency of the phase separation times. It was found that the phase separation time-temperature relationship follows the Arrhenius equation. The cure-induced phase separation activation energy E _a (ps) generated from the equation is independent of the method used to measure phase separation time. In our experimental ranges it is found that E _a (ps) is independent of the thermoplastic (TP) content, TP molecular weight and curing rate but it varies with the cure reaction kinetics and the chemical environments of the systems. __________ Translated from Acta Polymerica Sinica, 2007, 8: 725–730 [译自: 高分子学报]     

环氧树脂/聚砜共混体系相结构的调控研究——环氧预聚物分子量的影响

研究了不同分子量的环氧预聚物对双酚A型双官能团环氧树脂 /聚砜 (PSF) /固化剂 (二氨基二苯基砜 ,DDS)体系相分离结构的影响 .通过红外光谱 (FTIR)和动态热机械分析 (TMA)对反应转化率、玻璃化温度以及固化温度的关系的研究 ,表明环氧预聚物分子量较小时 ,凝胶点和玻璃化是影响相结构的关键因素 ;环氧分子量较大时 ,环氧扩链后粘度的变化则成为抑制相分离的重要因素 .电子显微镜 (SEM)结果表明改变环氧预聚物分子量可以达到调控相结构的目的 ,随着预聚物分子量的增大 ,体系的微区尺寸减小 .     

动力学因素对热诱导相分离法制备亲水性乙烯-丙烯酸共聚物微孔膜结构的影响

选择 3种不同丙烯酸含量的乙烯 丙烯酸共聚物 (EAA)为原材料 ,二苯醚 (DPE)为稀释剂 ,研究了淬冷温度、粗化时间等影响液滴生长的动力学因素对热诱导相分离法 (TIPS)制备EAA DPE亲水性高分子微孔膜结构的影响 .淬冷温度的高低决定了EAA DPE体系是发生液 液相分离还是固 液相分离 ,而产生相分离的机理不同将影响稀释剂液滴的生长 ,最终影响微孔膜的孔径 .实验结果表明 ,在相同粗化时间的条件下 ,随着EAA1 41 0 DPE、EAA3 0 0 2 DPE、EAA3 0 0 3 DPE三体系冷却温度的逐渐升高 ,孔径逐渐变大 .在结晶温度以下 ( 0℃、3 0℃、60℃ )粗化时间相同时 ,温度对微孔膜的孔径影响较小 ,例如 0℃和 3 0℃的恒温条件粗化 1 0min,微孔膜的孔径在 1～ 3 μm之间 ;在 60℃的恒温条件粗化 1 0min ,微孔膜的孔径在 3～ 5 μm之间 .而在 90℃的恒温条件粗化相同的时间 ,由于体系始终处于结晶温度线以上 ,体系始终处在液 液相分离区域 ,最终得到微孔膜的孔径达到了 6～8μm .在结晶温度以下 ( 3 0℃ )进行恒温粗化 ,由于体系的过冷程度很大 ,液滴相的粗化过程被抑制住 ,所以粗化时间对微孔膜的孔径影响不大 ;而在结晶温度以上 ( 90℃ )进行恒温粗化时 ,则是随着粗化时间的延长 ,微孔膜的孔径逐渐变大     

Reaction‐induced phase separation in epoxy/polysulfone/poly(ether imide) systems. I. Phase diagrams

Epoxy–aromatic diamine formulations are simultaneously modified with two immiscible thermoplastics (TPs), poly(ether imide) (PEI) and polysulfone (PSF). The epoxy monomer is based on diglycidyl ether of bisphenol A and the aromatic diamines (ADs) are either 4,4′‐diaminodiphenylsulfone or 4,4′‐methylenebis(3‐chloro 2,6‐diethylaniline). The influence of the TPs on the epoxy–amine kinetics is investigated. It is found that PSF can act as a catalyst. The presence of the TP provokes an increase of the gel times. Cloud‐point curves (temperature vs. composition) are shown for epoxy/PSF/PEI and epoxy/PSF/PEI/AD initial mixtures. Phase separation conversions are reported for the reactive mixtures with various TP contents and PSF/PEI proportions. On the basis of phase separation and gelation curves, conversion–composition phase diagrams at constant temperature are generated for both systems. These diagrams can be used to design particular cure cycles to generate different morphologies during the phase separation process, which is discussed in the second part of this series. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3953–3963, 2004     

Epoxy – diamine thermoset/thermoplastic blends: thermoset reactions and rheological evolutions during curing

Isothermal rates of reaction during the cure of epoxy‐amine/thermoplastic blends were studied. Epoxy‐amine reaction induces a phase separation. Experimental results show that when TP concentration is higher than 30 wt% an increase of reaction rate is observed after phase separation. A modelling of the kinetics of each phase before and after phase separation, shows that in the epoxy‐amine rich phase, gelation occurs for a conversion close to 0.6. Rheological behaviour was studied during the cure. The viscosity was found greatly dependent of the morphology, the epoxy amine conversion and of the evolution of the phase composition. Modelling of the viscosity using simple relations gives a good fit of the experimental results during the cure.     

Intractable high‐Tg thermoplastics processed with epoxy resin: Interfacial adhesion and mechanical properties of the cured blends

The intractable, high‐temperature‐resistant thermoplastics (TPs) polyphenylenether (PPE) and polyetherimide (PEI) were processed by dissolution into epoxy–amine precursors and a subsequent reaction of the precursors. Because the TP concentration was higher than the critical concentration, the phase separation produced a dispersion of crosslinked thermoset (TS) particles into a TP matrix. The morphology of the blends was examined with transmission electron microscopy and dynamic mechanical thermal spectroscopy, which showed completion of the phase separation. The interfacial adhesion at the TP‐matrix/TS‐particle interface was estimated on TP/TS bilayers to be 10 J/m² in PEI blends, whereas it was 70 J/m² in PPE blends, where there is strong evidence for in situ grafting between PPE phenolic chain ends and glycidyl functions of the reactive TS. Yielding in the compressive mode occurred at an intermediate yield stress between the components' values, and the anelastic deformation was separated from the plastic deformation. Fractures in the tensile mode occurred through debonding at the matrix/particle interfaces and coalescence of these defects, which led to microcrack formation and brittle failure. Mode I fracture toughness was, therefore, higher for PPE blends than for PEI blends, a result of the higher interfacial adhesion. However, a decrease from pure TP was observed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 363–373, 2001     

金属络合物的相转移催化分析与分离

以可简单分离回收、可反复使用为目标，详细介绍了相转移催化的变化发展过 程．通过对溶剂的选择，使得催化剂选择性地溶解在某一液相中，而使产物溶解在 另一液相中，如水-有机两相催化体系；通过温度的变化，简单地实现了在较高温 度下反应为均相体系以提高催化剂的活性，而在较低温度下实现了催化剂与产物不 相溶使得催化剂得以简单分离，如温控型水-有机两相催化体系、氟-有机两相催化 体系、温控型含氟催化剂、温控型有机金属催化剂等．     

BSA denaturation in the absence and the presence of urea studied by the iso-conversional method and the master plots method

The effect of cure temperature and modifier proportion on the miscibility of an epoxy–amine system with a thermoplastic modifier was studied by analysis of phase diagrams, morphologies, and glass transitions. Phase diagrams for the system before and during reaction were obtained from a thermodynamic analysis of phase separation using a model based on Flory–Huggins theory. Different types of morphologies were observed and analyzed in function of cure temperature and modifier proportion. The validity of the thermodynamic model was checked by comparing with observed morphologies. Two glass transitions were observed for most of the modified systems indicating that a phase separation was occurred.     

热致相分离法制备乙烯-三氟氯乙烯共聚物微孔膜

通过热致相分离法制备了乙烯-三氟氯乙烯共聚物(ECTFE)微孔膜, 考察了ECTFE与不同溶剂的相互作用参数对ECTFE/溶剂体系的液液相区的影响, 通过相容性分析及对ECTFE微孔膜断面结构的观察, 筛选出能与ECTFE发生明显液液相分离的溶剂--邻苯二甲酸二乙酯(DEP). 热力学相图证明, ECTFE/DEP体系具有较宽的液液相分离区, 偏晶点所对应的ECTFE质量分数高达55%. 考察了冷却条件对\{ECTFE/DEP体系膜断面结构的影响, 结果表明, 膜断面孔径随着淬冷温度的降低而减小, 在淬冷温度为458 K时膜断面孔径随粗化时间的增加而增大.