【作者】 刘峰；

【导师】 魏刚；

【作者基本信息】 西华大学 ， 材料学， 2008， 硕士

【摘要】 聚对苯二甲酸乙二酯(Polyethylene terephthalate)主要用于纤维生产,而PET在非纤领域的应用主要是制造饮料、食品等的包装容器及薄膜,尤其是饮料瓶的生产近年来得到很大发展。几乎所有的饮料瓶都是由PET树脂制备而成,其消费量以每年10%的速度迅猛增长,也由此带来了废弃PET瓶产生的白色污染。回收的PET瓶片“升级利用”,用作高性能工程塑料的仅占8.4%左右。研究开发回收PET瓶片(rPET)的再利用新技术,制备出高性能低成本的rPET改性工程塑料,不仅有利于资源的综合利用,减轻环境污染;同时就技术本身而言又能够开辟新的经济增长点。主要的研究内容及结果如下:(1)考察了酸酐类化学扩链剂均苯四甲酸二酐(PMDA)对聚对苯二甲酸乙二醇酯回收料(rPET)的扩链增粘改性。通过测定体系的特性粘度([η])、端羧基含量(CV),研究不同含量的PMDA对rPET扩链的影响,并通过DSC研究了扩链后rPET结晶性能的变化规律。研究发现,PMDA对rPET扩链效果明显。当PMDA用量为1.25%时,rPET的特性粘度为0.813dL/g,达到了rPET作为工程塑料使用的要求。当PMDA用量为1.5%时,PET的特性粘度达到最大值(0.968dL/g)。但rPET的特性粘度并不是随扩链剂含量的提高而一直提高,PMDA的用量与体系中端羟基含量有关。DSC研究发现,rPET的特性粘度越高,结晶性能越差。(2)将增粘后的rPET改性PC,制备得到PC/rPET共混合金。采用聚烯烃弹性体乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯(E-MA-GMA)对PC/rPET合金进行增容-增韧改性。当E-MA-GMA用量达到7.5%时,共混物发生脆韧转变,其缺口冲击强度和拉伸强度分别为58.76kJ/m~2和52.40MPa,表现出高强韧性。当弹性体用量继续增大到15%时,拉伸强度下降到44.74 MPa。SEM研究发现,E-MA-GMA作为反应性增容剂,使分散相PET颗粒变细。随着E-MA-GMA含量的增加,PET在PC/PET/E-MA-GMA共混体系中呈现出极不规则的近似条状或片状的形态结构。(3)研究了玻璃纤维增强及其与成核剂并用改性rPET复合材料的力学性能和热性能。首先考察了玻纤的含量对rPET复合材料力学性能、热性能以及结晶性能等的影响。然后制备得到添加稀土类成核剂的玻璃纤维增强改性rPET复合材料,考察了稀土类成核剂对复合材料力学性能和热性能的影响。研究发现,玻纤含量越高,材料的力学性能、热性能都有较大的提高,而且过冷度(△Tmc)降低,对rPET的结晶行为促进作用越明显。再加入成核剂后,材料的力学性能和热性能有进一步提高,但热性能的增幅没有力学性能的提高更明显。SEM研究发现,加入成核剂后,玻纤与树脂基体的界面结合更好,断裂拔出的玻纤表面由比较光滑变为带有明显附着物。更多还原

【Abstract】 Polyethylene terephthalate mainly used for fiber production, and PET in the field of application of non-fiber is manufactured beverages, food containers and packaging films, especially the production of beverage bottles are greatly developed in recent years. Almost all the bottles are prepared by the PET resin from its consumption to 10% per annum rate of rapid growth. At the same time, it has brought white pollution generated by PET waste bottles. The percentage of recyceled PET bottle films "escalation of use" for the high-performance engineering plastics is only about 8.4 percent. PET bottle recycling research and development of the re-use of new technologies, prepared by high-performance, low-cost rPET engineering plastics is conducive to the comprehensive utilization of resources and reduce environmental pollution; while for the technology itself, it can open up new economic growth Points. The main research and the results are as follows:(1) This thesis studied that recycled PET was modified with pyromellitic dianhydride(PMDA) to achieve a chain extension which was characterized by intrinsic viscosity and carboxyl value. The thermal and crystallizing behavior was studied by DSC. The results showed that Pyromellitic dianhydride has a good chain extension, and when the content of PMDA is 1.25%, intrinsic viscosity of rPET is 0.813dL/g , which has reached the using request of engineering plastics; and also has an effect on crystallizing behavior of PET.(2) The thesis studied PC was modified by rPET and its blending alloy. Polyolefin elastomer ethylene - methacrylate - glycidyl methacrylate (E-MA-GMA) is used to toughen and compatibilize the PC/rPET alloy. When the content of E-MA-GMA is 7.5%, the blend changes in brittle-ductile, notched impact strength and tensile strength were 58.76kJ/m2 and 52.40 MPa, showing high-strength toughness. When the content of elastomer increases to 15%, the tensile strength dropped to 44.74MPa. SEM study found, E-MA-GMA as the reaction of compatibilizer, dispersed PET particles thinner. With the content of E-MA-GMA increasing, PET in the PC/PET/E-MA-GMA blends shows a very irregular structure similar to strip or flake.(3) The thesis studied the mechanical properties and thermal properties of rPET composite material which was modified by glass fiber and nucleating agent. First of all, the test inspected the effect of the contents of glass fiber on the composite material’s mechanical properties, thermal properties and crystallizing behavior. Then a rare earth-like of nucleating agent is used to improve the mechanical properties and thermal properties of the composite material. Study found that the higher glass fiber content, the mechanical properties and thermal performance have greatly improved, andΔTmc is lower, the promotional effect for the crystallizing behavior of rPET is more obvious. Adding nucleating agents, the mechanical and thermal properties of the composite material have a further increase, but the increase of thermal performance is greater than the mechanical properties’. SEM studying found that adding nuclearing agents, the interface between glass fiber and resin matrix becomes better, and glass fibres pulled out by the fracture changed the smooth surface into a significant fixtures.更多还原