本文關鍵詞：EPDM基復合材料的sub-Rouse結構轉變及機理研究　出處：《中國科學技術大學》2017年碩士論文　論文類型：學位論文

  更多相關文章： 鏈段運動 sub-Rouse轉變 EPDM 溫度內耗譜 頻率內耗譜 力學性能

【摘要】：三元乙丙橡膠具有其耐臭氧、耐熱、耐候、耐老化性能優(yōu)異。在實際應用過程中,三元乙丙橡膠通常不能自己加工了單獨使用,為了改善橡膠的機械及功能特性,通常需要填充各種無機粒子。盡管用填充無機納米顆粒進行改善,但是會影響聚合物材料的力學性能和使用領域。本文主要討論三元乙丙橡膠的鏈段松弛行為,聚合物性能的改善取決于橡膠硫化網絡微觀結構是怎么改變的,那么,無機填料的引入是如何影響EPDM橡膠的交聯(lián)網絡及相應的宏觀性能的,是目前亟需解決的關鍵問題。本論文主要是從以下三個方面進行研究:1.EPDM/CaCO_3復合材料的sub-Rouse轉變行為。通過DMA數據分析,不同含量納米碳酸鈣對非完全交聯(lián)的三元乙丙橡膠的鏈段網絡結構松弛的行為的影響進行研究,可以得到三元乙丙橡膠的轉折溫度(即動力學轉折點)為385K,松弛時間的轉折點為0.18s,轉折點的發(fā)生時由于在轉折溫度下分子間的相互作用比較強烈,由于耦合作用的發(fā)生導致在隨著溫度倒數的增加,松弛時間的變化開始變得平緩,使得鏈段運動的增長趨勢減弱,在實驗的過程中不斷的增加納米碳酸鈣的含量,溫度轉折點是逐漸增加的,松弛時間的轉折點是逐漸降低的,這從微觀的角度更加充分的證實了無機碳酸鈣粒子的引入限制了三元乙丙橡膠的鏈段運動。2.CaCO_3對EPDM/PP/CaCO_3復合材料的sub-Rouse轉變行為及力學性能的影響。通過XRD、DSC、TEM、DMA和力學性能的測試,在非交聯(lián)的聚合物的共混EPDM/PP復合體系中,經過我們的研究發(fā)現(xiàn)PP對EPDM中sub-Rouse的影響可以忽略,隨著碳酸鈣含量在聚合物體系中增加,它增加了PP的結晶度,此時PP的結晶度對EPDM鏈段運動的阻礙作用占據主要地位,從而降低了EPDM鏈段的豫馳強度,使得轉折點的溫度升高:當碳酸鈣的含量增加到4phr時,碳酸鈣在EPDM中占據主要的地位,碳酸鈣含量的增加,使得EPDM鏈段的距離增加,促進了 EPDM鏈段的運動,使得轉折點的溫度不斷地下降。3.PP對EPDM/PP/CaCO_3復合材料的鏈段豫馳行為和力學性能的影響。本文制備了 EPDM/PP/CaCO_3三元納米復合材料,與之前不同的是這次是改變有機物聚丙烯對三元乙丙橡膠鏈段運動的改變,我們采用了 DSC設備對復合物的結晶度進行了測量,用動態(tài)力學分析儀來測試鏈段運動,同時還測得了復合物的力學性能。DSC的測量結果表明結晶度逐漸升高。動態(tài)力學分析儀(DMA)的數據表明了納米顆粒限制了三元乙丙橡膠的鏈段運動導致sub-Rouse轉變峰的強度降低,同時聚丙烯的加入使得復合物的結品度增加,阻礙了三元乙丙橡膠的鏈段運動,同樣的也導致sub-Rouse轉變峰的強度降低。同時也對三元復合材料進行了力學分析,聚丙烯是增強相,拉伸強度隨著PP含量的增加而增加;由于PP和EPDM的分散情況導致了斷裂伸長率隨著含量的增加先減少后增加。
[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.
【學位授予單位】：中國科學技術大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TQ333.4;TB332

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