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氟橡胶的改性及其纳米尺度互穿网络形态研究

Study on the Modification and Nanoscale Interpenetrating Network Morphology of Fluoroelastomer

【作者】 陈春明

【导师】 熊传溪;

【作者基本信息】 武汉理工大学 , 材料学, 2006, 博士

【摘要】 互穿聚合物网络(IPNs)是一种特殊类型的聚合物共混物,其中一相或两相发生交联而形成相互贯穿的聚合物网络。依赖聚合物的共混比例、形态、交联密度和特性,IPNs显示出特殊的性能。IPNs的制备被认为是限制不相容聚合物共混物相分离的独特方法。由于两相的特殊排列,IPNs材料常常展现出良好的力学强度和韧性。因而,IPNs技术被广泛地应用于聚合物材料的改性。氟橡胶(FKM)具有突出的耐高温,耐油,耐化学腐蚀,耐老化等性能,应用于特殊的密封材料等方面,然而由于存在着弹性低,耐低温性能差等弱点限制了它的应用范围。本论文依据创新性的思维,围绕改善FKM的性能,采用四条技术路线,成功地制备出一系列新的FKM的IPNs材料,并对其结构、组成与性能的关系进行了研究,获得了以下研究成果: 1.采用熔融机械共混的方法,使氟橡胶(FKM)和丁腈橡胶(NBR)在高温和强剪切作用下相容,然后在各自不同的硫化体系下硫化,使两相各自交联,从而制备了FKM/NBR IPNs。 2.采用TEM、DSC和DMA等方法进行了FKM/NBR IPNs的形态、热力学性能和动态力学性能研究,并研究了两网络的组成对机械性能和热稳定性的影响。研究结果显示,FKM/NBR IPNs体系中,材料优异的力学性能是由于互穿网络产生的协同效应的结果,而网络中纳米尺度相畴尺寸越均匀,双连续相形态越规整、完善,引起材料力学性能的提高也越显著。当FKM/NBR为80/20(w/w)时,共混体系获得最完善的两相连续的互穿网络结构,拉伸强度和撕裂强度达到最大值。其玻璃化转变温度只有一个值为-16℃,介于纯的FKM和NBR玻璃化转变温度之间,表明互穿网络的形成促进了FKM和NBR之间的相容性。该技术路线的实施,提升了氟橡胶的抗撕裂强度和低温柔韧性。 3.对FKM/NBR互穿网络的形成机理进行了研究。采用浊点法,绘制了FKM/NBR共混体系的相图,研究了相分离行为与熔融共混的温度的关系。研究结果表明,两相的相容性、共混比例、粘度比以及加工条件对互穿网络的形成产生显著的影响。 4.采用密炼机通过熔融共混的方法,使FKM和环氧丙烯酸酯橡胶(EACM)在高温和强剪切作用下相容,然后在各自不同的硫化体系下硫化,使两相各自

【Abstract】 Interpenetrating polymer networks (IPNs) are relatively special types of polymer blends where one or both phases are cross-linked. Depending on the blend ratio, morphology, cross-link density and nature of component polymers, the IPNs show characteristic properties. IPN preparation is considered as the unique way of restricting phase separation in immiscible polymer blend. Due to the unique arrangement of the two phases in an IPN, these materials often exhibit good mechanical strength and toughness. IPNs technology has widely applied in modification of polymer materials. Fluoroelastomer (FKM) is used as a specialty polymer in a variety of applications such as seals, O-rings, tubes, hose and cables. It is well known for their resistance to heat and aggressive fluid environments. However, the poor flexility at low temperature limits some of its application. In this thesis, in terms of some unique idea, a series of new FKM IPNs with improvement properties, have been successfully prepared by using four technique approaches, the relation between structure, morphology, composition and properties were investigated systematically. The main results obtained are summarized as follows:1. The preparations of interpenetrating polymer networks (IPNs) based on fluoroelastomer/ butadiene-acrylonitrile rubber (FKM/NBR) by molten blending at high temperature, shear process and respective chemical cross-linked of two components was investigated.2. The morphology and thermodynamics for FKM/NBR IPNs were investigated by transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMA). Special focus was placed on the phase continuity since it strongly influences the mechanical properties of the polymer blend. The influence of the two networks component on the mechanical properties and thermostabilities was studied. Base on the results of the morphology and mechanical studies, the excellent mechanical properties of the FKM/NBR IPNs were caused by the synergistic effects of co-continuous phase with small phase domains of 50-200nm and perfect interpenetrating network structure. Mechanical testing indicated a synergistic effect at the 80/20 FKM/NBR with maximum values for both

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