固化条件对环氧树脂/丙烯酸酯橡胶共混体系结构与性能的影响

利用丙烯酸酯橡胶(ACM)提高热固性环氧树脂(EP)的韧性,系统研究共混体系固化条件对材料结构和性能的影响.研究表明,固化前环氧树脂与丙烯酸酯橡胶在整个组成范围内为均相体系,固化过程中两组份分子量不断增大,部分组成环氧树脂/丙烯酸酯橡胶共混体系(80/20及50/50)发生反应诱导相分离现象(RIPS).在发生反应诱导相分离的体系中,分相后的环氧树脂和丙烯酸酯橡胶两相彼此包含对方的组分,是一种不彻底的相分离.同时,固化后材料的结构与性能强烈依赖于所用固化条件(包括固化时间、固化温度及固化剂含量等).因此,可以通过调节体系固化条件实现对环氧树脂/丙烯酸酯橡胶共混体系结构和性能的调控.     

聚醚增韧环氧树脂的研究

通过端羟基聚四氢呋喃和顺丁烯二酸酐的反应制备了端羧基聚醚。用浊度测定、动态力学实验和扫描电镜观察等方法研究了聚醚增韧环氧树脂的结构形态。聚醚的分子量、端羧基含量以及固化条件对聚醚相颗粒尺寸有很大的影响。这些因素又进一步影响固化产物的力学性能。端羧基聚四氢呋喃作为环氧树脂的增韧剂有两个优点:(1)橡胶相的玻璃化温度低;(2)环氧树脂的耐热性不因添加增韧剂而降低。     

动态固化聚丙烯/环氧树脂共混物的研究

将动态硫化技术应用于热塑性树脂 热固性树脂体系 ,制备了动态固化聚丙烯 (PP) 环氧树脂共混物 .研究了动态固化PP 环氧树脂共混物中两组分的相容性、力学性能、热性能和动态力学性能 .实验结果表明 ,马来酸酐接枝的聚丙烯 (PP g MAH)作为PP和环氧树脂体系的增容剂 ,使分散相环氧树脂颗粒变细 ,增加了两组分的界面作用力 ,改善了共混物的力学性能 .与PP相比 ,动态固化PP 环氧树脂共混物具有较高的强度和模量 ,含 5 %环氧树脂的共混物拉伸强度和弯曲模量分别提高了 30 %和 5 0 % ,冲击强度增加了 15 % ,但断裂伸长率却明显降低 .继续增加环氧树脂的含量 ,共混物的拉伸强度和弯曲模量增加缓慢 ,冲击强度无明显变化 ,断裂伸长率进一步降低 .动态力学性能分析 (DMTA)表明动态固化PP 环氧树脂共混物是两相结构 ,具有较高的储能模量 (E′)     

环氧树脂/氧化石墨纳米复合物的等温固化行为研究

用示差扫描分析仪(DSC)研究了氧化石墨(GO)对N,N,N',N'-四缩水甘油基-4,4'-二氨基二苯基甲烷环氧树脂(TGDDM)/4,4'-二氨基二苯基砜(DDS)体系的等温固化反应的影响,用X射线光电子能谱仪(XPS)和傅里叶变换红外光谱仪(FTIR)研究了GO上存在的官能团及其对TGDDM/DDS体系固化行为的影响,用热失重分析仪(TGA)研究了天然石墨和GO的热力学稳定性.XPS、FTIR和TGA结果表明,GO上存在的大量羟基、羧基、环氧基等官能团能够影响环氧树脂的固化行为.DSC研究发现,环氧树脂/氧化石墨纳米复合物的固化反应属于自催化类型,随着GO含量的增加,达到最大反应速率的时间不断减小,初始反应速率不断增大,这说明GO对环氧树脂的固化反应有促进作用.Kamal模型计算得到的结果表明,随着GO含量的增加自催化反应初期阶段表观活化能E1先减小再增大,而自催化反应结束后表观活化能E2略微减小.经Kamal模型扩散控制函数修正后,整个固化过程中拟合得到的结果与实验数据相当吻合.以上结果说明,少量的GO对TGDDM/DDS体系的固化反应起着催化作用.     

升温与等温法非模型动力学研究环氧树脂固化反应

基于DSC数据,采用以Vyazovkin积分法为基础的升温法非模型动力学和等温法非模型动力学对双酚A型环氧树脂E51/4,4′-二氨基二苯基砜(DDS)体系及多官能度环氧树脂AG80/DDS体系的固化过程进行了研究,并结合玻璃化转变温度的变化和原位红外测试技术,对比分析了升温与等温条件下的固化反应规律.结果表明,与传统的模型拟合法相比,非模型动力学更适合定量预测树脂固化反应过程,并能为固化过程中反应机理变化的研究提供重要依据;等温法非模型动力学能够更好地预测两种树脂体系在不同恒温条件下的固化反应历程,并且升温法与等温法非模型动力学所得到的反应活化能-固化度之间的变化关系不同,表明不同温度条件下树脂的反应机理不同,这与升温和恒温条件下玻璃化效应及环氧官能团的变化规律相吻合.     

丁腈橡胶和聚乙二醇增韧环氧树脂制备胶粘剂及性能研究

本文在加热下环氧树脂(Polyethylene Glycol, EP)开环与端羧基丁腈橡胶(carboxyl-terminated Butadiene acrylonitrile, CTBN)与发生酯化反应生成预聚物,然后选用单一固化剂聚醚胺(Polyetheramine, D400)和混合固化剂聚乙二醇(Polyethylene Glycol, PEG,Mn=2000)与二乙基甲苯二胺(Diethyltoluene diamine, DETDA)作用下固化及粘接木块。重点探讨CTBN、EP、D400和PEG与DETDA各组成的用量对环氧树脂基粘胶性能的影响,并通过红外判定主要官能团反应,重点探讨胶粘固化物的润湿性、吸水性、拉伸强度和热重手段评价其环氧树脂粘胶性能。结果表明随着CTBN用量的增加,增韧环氧树脂的固化效果越来越好,但是增加到一定程度,有副反应的作用导致其固化效果与粘性都会逐渐降低。结论：对固化物进行表征综合评价,CTBN、EP和固化剂的质量比为1∶5∶2时,其粘性最强,韧性最高,进一步研究有望获得市场欢迎的产品。     

基于可逆动态共价化学的新型可修复、可回收、可加工环氧树脂

利用生物来源的二聚脂肪酸为原料,合成了二聚酸酰肼和二聚酸酰腙两种衍生物,并进一步以其作为环氧E-44树脂固化剂,得到了新型的含动态共价连接的热固性环氧树脂。采用傅里叶红外光谱(FT-IR)、差式扫描量热(DSC)、扫描电子显微镜(SEM)、热重(TG)和动态力学分析(DMA)等多种测试手段对环氧树脂固化过程以及固化后材料的结构与性能关系进行了详细表征,特别研究了动态亚胺键对热固性环氧树脂性能的独特影响。结果表明:与传统环氧树脂相比,改性后的环氧树脂有更好的韧性,且其玻璃化转变温度及热稳定性没有明显下降。在升温和加压的条件下,酸可催化亚胺键的动态交换反应,赋予传统环氧树脂以全新的可修复、可回收与可多次加工性能。     

含介晶结构单元化合物改性环氧树脂E—51／DDM固化体系的动态力学行为

合成和表征了含有介晶结构单元的单环氧官能团化合物4-(4'-甲基基苯甲酰氧基)苯基缩水甘油醚(MPEP),以一定比例的MPEP加入到环氧树脂E-51/4,4'-二氨基二苯基甲烷(DDM)固化体系,获得了一系列在高分子链上悬挂介晶结构单元的固化网络结构,并对其动态力学行为进行了表征,侧链上介晶结构单元的引入使固化体系的交联密度降低,链段柔顺性增加,表现为与未加MPEP的体系相比,含有介晶结构单元的体系的玻璃化温度和动态模量下降,而且MPEP的加量越大,玻璃化温度和动态模量下降幅度越大.     

二维红外相关光谱在双氰胺固化环氧树脂体系中的应用

利用原位红外加热炉模拟双氰胺固化环氧树脂体系的固化反应过程,实时测试并记录反应过程中官能团结构的变化;将一维红外光谱和二维红外光谱相结合进行分析,给出固化过程中各官能团的变化顺序和趋势。 在双氰胺固化环氧树脂体系中,双氰胺首先分解成氰基胺,然后再和环氧树脂发生开环加成反应,生成亚胺结构,通过重排生成酰胺结构。 双氰胺分解为氰基胺的反应是可逆反应。 将原位红外、一维红外与二维红外三者结合是阐明热固性树脂固化反应机理的非常有效的手段。     

吸水过程对环氧树脂的动态松弛行为的影响

以酚醛树脂和乙酸、正丁酸和苯乙酸酯化的酚醛树脂固化邻甲酚环氧树脂.应用称重法、示差扫描量热法(DSC)和动态机械分析法(DMA)等手段研究吸水过程对环氧树脂的动态松弛行为的影响.结果表明,吸水过程对酚醛树脂和酯化酚醛树脂固化体系的动态松驰行为有显著的影响,这是由于两种体系中侧基对吸水过程及与水分子的相互作用不同所致.     

PHASE STRUCTURE AND PROPERTIES OF EPOXY RESIN MODIFIED BY POLYSILOXANE BEARING PENDANT AMINO GROUPS

Polysiloxane-modified epoxy resins were prepared through the reaction of epoxy resin with polydimethylsiloxanesbearing pendant N-(β-aminoethyl)-γ-aminopropyl groups. The morphology and properties of the cured epoxy resins modifiedby the polysiloxanes were investigated. It was found that the phase structure and properties of the cured epoxy resins dependmainly on the amino group content in the polydimethylsiloxane and the level of the modifier. The change of phase structurein the cured epoxy resin systems was responsible for the dramatic change in their mechanical and surface properties.     

Cure Kinetics of a Tetrafunctional Rubber Modified Epoxy-amine System

In this work the curing kinetics behaviour of a rubber modified epoxy amine system is investigated through calorimetric analysis. This study is part of a wider investigation on new epoxy formulations to be used as matrices of composite materials. The aim is to enhance both the processing behaviour and the mechanical properties of the matrix in order to obtain higher performance composites for more demanding applications. The epoxy system is blended with a high molecular mass rubber containing functional groups reactive towards the epoxies. The formation of a rubber/epoxy network can be achieved by means of a 'pre-reaction' between the epoxy monomers and the rubber functional groups, carried out in the presence of a suitable catalyst and before the resin is cured with the amino hardener. In this work the influence of both the rubber and the catalyst on the resin cure kinetics is analysed. This revised version was published online in July 2006 with corrections to the Cover Date.     

化学结构变化对刚棒状环氧树脂相行为和热力学性能的影响

用线性酚醛树脂(PN)和4-氨基苯基氨基砜(SAA)作为固化剂, 与刚性棒状环氧树脂联苯环氧(DGEBP)、四甲基联苯环氧(DGETMBP)和传统双酚A环氧树脂(DGEBA)分别进行固化. 研究了固化剂和环氧树脂化学结构的改变对热固网络相行为和热力学性能的影响. 结果表明, 刚性环氧网络比传统的DGEBA具有更好的热力学性能. DGEBP可形成不同类型的取向网络, 而取向态的类型也直接影响了热固网络的热力学性能. 用扫描电镜(SEM)观察不同网络体系的断裂面结构, 发现取向的刚性棒状环氧网络的断裂面呈韧性断裂, 而其它无定形环氧网络则呈典型的脆性断裂.     

活性酯固化环氧树脂物性的研究

主要对活性酯固化环氧树脂的吸水性、高耐湿性、电气特性等方面进行了研究,同时也对其树脂极性、交联结构、分子链运动等方面也进行了研究．     

硅橡胶/氟橡胶并用胶的制备及力学性能

硅橡胶和氟橡胶作为国防、航天等重要领域的耐热材料一直被人们青睐,但其有着各自地优缺点且价格昂贵,本文尝试将这两种橡胶制成并用胶以解决氟橡胶不耐低温和加工性差的问题,以期增大其使用温度范围。采用机械共混法制备硅橡胶/氟橡胶并用胶,研究了硅橡胶和氟橡胶的混炼工艺、并用比、共硫化体系和硫化条件对并用胶力学性能的影响。结果表明,当硅橡胶/氟橡胶的质量比为10∶90,共硫化体系为3~#硫化剂/过氧化二异丙苯(DCP),一段硫化温度为170℃、硫化压力为10MPa、硫化时间为30min,二段硫化温度为200℃、硫化时间为6h时,并用胶的力学性能达到最好。     

丁腈橡胶的配位硫化

在丁腈橡胶中引入无机金属盐粒子,通过腈基与金属离子之间的固相配位反应来实现丁腈橡胶的配位硫化,创建了一个完全不同于传统硫磺硫化体系的新型非共价键配位交联的橡胶网络体系.同时制备了具有优异的力学性能的配位硫化橡胶材料,既可以作柔性的橡胶材料使用,也可以作为韧性、脆性的塑料材料使用.本文就影响配位交联反应的两个关键因素(金属盐粉末的粒径和丁腈橡胶的丙烯腈含量)进行了探讨,提出了提高配位硫化效率的办法(结晶水、增塑剂等).     

丁腈羟增韧环氧树脂形态与力学性能

研究了丁腈羟增韧环氧树脂的力学性能和形态结构，丁腈羟的用量、丁腈羟中丙烯腈的含量、固化条件对所形成的微区尺寸都有较大影响，并进一步影响固化物的力学性能。     

Blending of Natural Rubber/Recycled Ethylene-Propylene-diene Rubber: Promoting the Interfacial Adhesion Between Phases by Natural Rubber Latex

This article deals with blends based on natural rubber (NR) and recycled ethylene-propylene-diene rubber (R-EPDM). Natural rubber latex (NRL) was introduced into the blends to enhance interfacial adhesion between NR and R-EPDM. A new route of compounding was also suggested. The blends were prepared by mixing R-EPDM and other additives in NRL before blending with natural rubber on a two-roll mill. By applying this method, the homogeneity of the blends and cross-linking distribution are significantly improved. The blends exhibited superior state of cure, swelling resistance, mechanical properties and dynamic mechanical properties. The degree of entanglement between NR and R-EPDM also increased after NRL modification.     

Design and Synthesis of Transparent Poly （acrylonitrile-butadiene-styrene） and Relationship Between Its Phase Construction and Transparency

IntroductionABS resins have been widely applied to the field ofengineering materials because of their excellent me-chanical,electrical,physical,and chemical proper-ties.Typically,ABS resins comprise a rigid copolymermatrix-phase dispersed in a graft copol…     

Modification of epoxy resin using reactive liquid (ATBN) rubber

Epoxy resins are widely utilised as high performance thermosetting resins for many industrial applications but unfortunately some are characterised by a relatively low toughness. In this respect, many efforts have been made to improve the toughness of cured epoxy resins by the introduction of rigid particles, reactive rubbers, interpenetrating polymer networks and engineering thermoplastics within the matrix.In the present work liquid amine-terminated butadiene acrylonitrile (ATBN) copolymers containing 16% acrylonitrile is added at different contents to improve the toughness of diglycidyl ether of bisphenol A epoxy resin using polyaminoimidazoline as a curing agent. The chemical reactions suspected to take place during the modification of the epoxy resin were monitored and evidenced using a Fourier transform infrared. The glass transition temperature (T_g) was measured using a differential scanning calorimeter. The mechanical behaviour of the modified epoxy resin was evaluated in terms of Izod impact strength (IS), critical stress intensity factor, and tensile properties at different modifier contents. A scanning electron microscope (SEM) was used to elucidate the mechanisms of deformation and toughening in addition to other morphological features. Finally, the adhesive properties of the modified epoxy resin were measured in terms of tensile shear strength (TSS).When modifying epoxy resin with liquid rubber (ATBN), all reactivity characteristics (gel time and temperature, cure time and exotherm peak) decreased. The infrared analysis evidenced the occurrence of a chemical reaction between the two components. Addition of ATBN led to a decrease in either the glass transition temperature and stress at break accompanied with an increase in elongation at break and the appearance of some yielding. As expected, the tensile modulus decreased slightly from 1.85 to about 1.34 GPa with increasing ATBN content; whereas a 3-fold increase in Izod IS was obtained by just adding 12.5 phr ATBN compared to the unfilled resin. It is obvious that upon addition of ATBN, the Izod IS increased drastically from 0.85 to 2.86 kJ/m² and from 4.19 to 14.26 kJ/m² for notched and unnotched specimens respectively while K_IC varies from 0.91 to 1.49 MPa m^1/2 (1.5-fold increase). Concerning the adhesive properties, the TSS increased from 9.14 to 15.96 MPa just by adding 5 phr ATBN. Finally SEM analysis results suggest rubber particles cavitation and localised plastic shear yielding induced by the presence of the dispersed rubber particles within the epoxy matrix as the prevailing toughening mechanism.