EPDM基复合材料的sub-Rouse结构转变及机理研究

发布时间：2018-01-15 07:22

本文关键词：EPDM基复合材料的sub-Rouse结构转变及机理研究　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：三元乙丙橡胶具有其耐臭氧、耐热、耐候、耐老化性能优异。在实际应用过程中,三元乙丙橡胶通常不能自己加工了单独使用,为了改善橡胶的机械及功能特性,通常需要填充各种无机粒子。尽管用填充无机纳米颗粒进行改善,但是会影响聚合物材料的力学性能和使用领域。本文主要讨论三元乙丙橡胶的链段松弛行为,聚合物性能的改善取决于橡胶硫化网络微观结构是怎么改变的,那么,无机填料的引入是如何影响EPDM橡胶的交联网络及相应的宏观性能的,是目前亟需解决的关键问题。本论文主要是从以下三个方面进行研究:1.EPDM/CaCO_3复合材料的sub-Rouse转变行为。通过DMA数据分析,不同含量纳米碳酸钙对非完全交联的三元乙丙橡胶的链段网络结构松弛的行为的影响进行研究,可以得到三元乙丙橡胶的转折温度(即动力学转折点)为385K,松弛时间的转折点为0.18s,转折点的发生时由于在转折温度下分子间的相互作用比较强烈,由于耦合作用的发生导致在随着温度倒数的增加,松弛时间的变化开始变得平缓,使得链段运动的增长趋势减弱,在实验的过程中不断的增加纳米碳酸钙的含量,温度转折点是逐渐增加的,松弛时间的转折点是逐渐降低的,这从微观的角度更加充分的证实了无机碳酸钙粒子的引入限制了三元乙丙橡胶的链段运动。2.CaCO_3对EPDM/PP/CaCO_3复合材料的sub-Rouse转变行为及力学性能的影响。通过XRD、DSC、TEM、DMA和力学性能的测试,在非交联的聚合物的共混EPDM/PP复合体系中,经过我们的研究发现PP对EPDM中sub-Rouse的影响可以忽略,随着碳酸钙含量在聚合物体系中增加,它增加了PP的结晶度,此时PP的结晶度对EPDM链段运动的阻碍作用占据主要地位,从而降低了EPDM链段的豫驰强度,使得转折点的温度升高:当碳酸钙的含量增加到4phr时,碳酸钙在EPDM中占据主要的地位,碳酸钙含量的增加,使得EPDM链段的距离增加,促进了 EPDM链段的运动,使得转折点的温度不断地下降。3.PP对EPDM/PP/CaCO_3复合材料的链段豫驰行为和力学性能的影响。本文制备了 EPDM/PP/CaCO_3三元纳米复合材料,与之前不同的是这次是改变有机物聚丙烯对三元乙丙橡胶链段运动的改变,我们采用了 DSC设备对复合物的结晶度进行了测量,用动态力学分析仪来测试链段运动,同时还测得了复合物的力学性能。DSC的测量结果表明结晶度逐渐升高。动态力学分析仪(DMA)的数据表明了纳米颗粒限制了三元乙丙橡胶的链段运动导致sub-Rouse转变峰的强度降低,同时聚丙烯的加入使得复合物的结品度增加,阻碍了三元乙丙橡胶的链段运动,同样的也导致sub-Rouse转变峰的强度降低。同时也对三元复合材料进行了力学分析,聚丙烯是增强相,拉伸强度随着PP含量的增加而增加;由于PP和EPDM的分散情况导致了断裂伸长率随着含量的增加先减少后增加。
[Abstract]:Ethylene-propylene diene diene diene rubber (EPDM) has excellent properties of ozone resistance, heat resistance, weathering resistance and aging resistance. In order to improve the mechanical and functional properties of rubber, a variety of inorganic particles are usually filled. However, the mechanical properties and application fields of polymer materials will be affected. In this paper, the chain relaxation behavior of EPDM is mainly discussed. The improvement of polymer properties depends on how the microstructure of rubber vulcanization network changes. So, how the introduction of inorganic filler affects the crosslinking network and the corresponding macroscopic properties of EPDM rubber. It is the key problem that needs to be solved at present. This paper mainly studies from the following three aspects:. 1. The sub-Rouse transition behavior of EPDM / CaCO3 composites. DMA data were analyzed. The effects of different content of nano-CaCO3 on the relaxation of the chain structure of non-fully crosslinked EPDM were studied. The turning temperature of EPDM is 385K, and the turning point of relaxation time is 0.18s. When the turning point occurs, the intermolecular interaction is stronger at the transition temperature, and the relaxation time changes gradually with the increase of the reciprocal temperature due to the coupling effect. The increasing trend of the chain motion is weakened, and the temperature turning point is increasing gradually, and the relaxation time turning point is gradually decreasing. From the microcosmic point of view, it is more fully confirmed that the introduction of inorganic calcium carbonate particles restricts the segment movement of EPDM. 2. The su of CaCOS3 to EPDM/PP/CaCO_3 composites. Effect of b-Rouse transition behavior and mechanical properties through XRD. DSC-Tem EPDM/PP and mechanical properties were tested in non-crosslinked polymer blend EPDM/PP composite system. We found that the effect of PP on sub-Rouse in EPDM is negligible. With the increase of calcium carbonate content in polymer system, it increases the crystallinity of PP. At this time, the degree of crystallinity of PP has a dominant effect on the movement of EPDM segment, thus reducing the relaxation strength of EPDM segment. When the content of calcium carbonate increased to 4phr, calcium carbonate occupied the main position in EPDM, and the increase of calcium carbonate content increased the distance of EPDM segment. Promoted the movement of EPDM segment. The effect of PP on the chain behavior and mechanical properties of EPDM/PP/CaCO_3 composites was investigated. EPDM/PP/CaCO_3 ternary nanocomposites. In contrast to the previous change in the movement of organic polypropylene to the EPDM segment, the crystallinity of the composite was measured using a DSC device. The motion of the chain was measured by dynamic mechanical analyzer. At the same time, the mechanical properties of the composites were measured. DSC results showed that the crystallinity increased gradually. Dynamic Mechanics Analyzer (DMA). The results showed that the sub-Rouse transition peak strength was decreased due to the restriction of the chain motion of EPDM. At the same time, the addition of polypropylene increased the binding degree of the composite, which hindered the segment movement of EPDM. At the same time, the strength of the sub-Rouse transition peak was decreased. The mechanical analysis of the ternary composites also showed that polypropylene was a reinforced phase, and the tensile strength increased with the increase of PP content. Because of the dispersion of PP and EPDM, the elongation at break decreases first and then increases with the increase of content.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ333.4;TB332

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