【作者】 王晓艳；

【导师】 严海彪； 陈绪煌；

【作者基本信息】 湖北工业大学 ， 材料学， 2010， 硕士

【摘要】 聚酯(PET)因价格低廉,具有优良的耐热性、耐化学药品性、耐磨性、电绝缘性等优点,但是其冲击强度低、脆性大等缺点却限制了其应用领域,所以研究作为工程塑料使用的高性能PET,不仅可以扩大其应用领域,同时也可以使PET废弃物回收利用,变废为宝,具有重要的学术研究价值和良好的社会、经济效益。本论文采用扩链剂对PET及rPET进行扩链改性,分析其共混体系的特性粘度的变化,优化扩链剂及其配比；同时也采用增韧剂增韧PET,研究了不同体系下的力学性能、热性能、动态粘弹性及其微观性能。本论文的主要研究结果如下：首先考察了干燥时间对PET/rPET的特性粘度的影响,通过乌氏粘度计来测定聚酯PET/rPET的特性粘度可知,试样在170℃下干燥8个小时时,在密炼过程中的水降解程度是最小的。并考察了PMDA及A900对PET/rPET的扩链增粘改性。通过测定体系的特性粘度及粘均分子量,研究不同重量百分含量的PMDA及A900并与1010复配后对PET/rPET扩链的影响,并通过DSC来研究扩链后的PET/rPET结晶性能的变化规律。经研究表明,PMDA对聚酯的扩链效果要优于A900的。并且对共混体系的扩链效果明显。当PMDA的用量达到0.6wt.%时,PET/rPET的特性粘度分别达到最大值为0.93815dL/g,0.79587 dL/g,达到了PET/rPET作为工程塑料使用的最低要求。当超过最大特性粘度值后,再加入扩链剂的用量,特性粘度反而会下降。DSC测试结果发现,PET/rPET的特性粘度越高,结晶性能越差。最后通过增韧剂((1)、E-MA-GMA; (2)、POE-g-MA; (3)、SEBS-g-MA; (4)、PTW)来增韧改性PET。实验结果表明,增韧剂2对聚酯PET的增韧改性效果最佳,而且当其用量为6wt.%时,其冲击强度比纯聚酯PET提高了75.8%左右,其拉伸断裂伸长率升高了58.4%；当其用量达到12wt.%时；其冲击强度提高了184%左右,其断裂伸长率升高了147.8%,表现出高韧性。同样在共混体系的DMA测试、SEM测试中,也证实了前面力学测试得出的结论。更多还原

【Abstract】 Poly (ethylene terephthalate) (PET) is the thermoplastic that has low cost, high performance. However, the most serious shortcoming of this material is its very low impact strength. The research on the high-performance, the high-added value PET used as the engineering plastic has the important social、the economic significance and the academic value, which solves the contradiction between PET production capacity growth and the product demand growth in our country and also disposes of the more and more PET waste. In this paper we studied that PET/rPET was modified with chain extenders and find the best chain extender by contrasting and analyzing the intrinsic viscosity of PET/rPET and the crystallization performance that was tested by DSC; then we investigated that PET was toughened with polyester elastomer and the different systems’ mechanical properties, thermal properties, dynamic viscoelasticity and microcosmic performance. The key findings of this paper are as follows:First, the impact on the intrinsic viscosity of drying time on PET/rPET was studied. Through the intrinsic viscosity of the PET/rPET that was tested by Ubbelohde viscometer we can see, the blends in the mixing process had the smallest degree of water degradation when the specimen at 170℃dry 8 hours. And the bicyclic anhydride types of chemical chain extenders PMDA and A900 in the PET/rPET modification of the extended chain of increased viscosity was examined. We studied the chain-extension effect of PET/rPET with different contents of PMDA and A900 by measuring the viscosity, moreover, we studied the regularity for change of crystalline properties by DSC when PET/rPET was extendered. The research shows that, the effect of the chain extender (PMDA) on polyester is better than A900. The intrinsic viscosity of PET/rPET is respectively 0.93815dL/g and 0.79587 dL/g when the percentage of PMDA to reach 0.6wt.%, which reached the minimum requirement of PET/rPET, used engineering plastics. We found that the intrinsic viscosity of polyester didn’t increase with the content of chain extenders improving, and when the intrinsic viscosity of PET/rPET exceeds the maximum value, it would drop if we continue to add chain extenders. The intrinsic viscosity of PET/rPET was inversely proportional to its crystalline properties by DSC.Second, using elastomers ((1), E-MA-GMA; (2), POE-g-MA; (3), SEBS-g-MA; (4), PTW) to toughening modification of PET. The experimental results show that the best toughening modification of the PET is the second elastomer, when its dosage is 6 wt.%, PETimpact strength increased about 75.8% than pure polyester PET, its tensile elongation at break rate increased by 58.4%; when its using reached 12 wt.%; the impact strength increased about 184% and its elongation at break increase of 147.8%, demonstrated high toughness. We could find this trend in tests result in the DMA and SEM tests.更多还原