| Polyethylene terephthalate)(PET) is a low cost, high performance thermoplastic. Its major use is in fabrics and soft drink bottles, due to its excellent chemical resistance, wear resistance and barrier properties. However, the most serious shortcoming of this material is its very low impact strength. By filling and blending with nano-CaCO3 and polyethylene-octene copolymer(POE), this paper investigates different systems' mechanical and Theological properties, also crystallization properties are researched.The thesis consists of three parts:Chapter 2 focuses on the effects of the content of nano-CaCO3 and different treat agent on the mechanical, crystallization properties of PET.In chapter 3, preliminary results on the toughening effectiveness of PET by POE-g-MA are presented; in addition, a comparative fundamental study was performed regarding the influence of heat treatment on toughening of PET/POE-g-MAH blends.The effects of the modified POE (M-POE) on the mechanical strength of PET have been investigated in chapter 4. Furthermore, the effect of different treat agent and different technology on mechanical, rheological and crystallization properties of PET/ M-POE/nano-CaCO3 blends have also been discussed.Following conclusion are made:1. In PET/ nano-CaC03 composites, untreated nano-CaCO3 can slightly increase the impact strength, however, both treated with stearic acid and titanate would result in the decrease of the impact strength. In addition, the content of treated agent added more, the impact strength of composites was lower. When nano-CaCO3 content is blow 10 phr, the tensile strength almost remain, butover 10 phr, the tensile strength decline greatly.2.added nano-CaCO3, the glass transition temperature(Tg) of composites were declined. In addtion, nano-CaCO3 can improve the crystallization properties of PET.3.The heat treatment can remarkably increase not only the tensile strength but also notched impact strength of PET/ POE-g-MA blends. A maximum in the impact strength of the PET/ POE-g-MA is observed when the modified elastomer concentration in the blend is 30 phr in our experiment. At this concentration, the notched Izod impact strength increase approximately 9 times and 2.5 times compared to that of pure PET and same concentration un-annealed samples, respectively.4.M-POE has good compatibility with PET and the use of POE-g-MA can improve notched Izod impact strength of PET/M-POE blends. Comparing with pure PET, blend of PET/M-POE (100/30, weight fraction) improve the impact strength about 17 times, which is evidently higher than many reported results. The brittle-tough transition is appeared when M-POEcontent is 15 phr.5.There are not cooperative toughening effects when the PET, M-POE and nano-CaCO3 were directly mixed together, and during the content of nano-CaCO3 increase, the impact strength of PET/ M-POE/nano-CaCO3 composites decrease gradually.6.Different treated agent would influence the distribution of nano-CaCO3 in blend system and influence the mechanical properties. The nano-CaCO3 treated with stearic acid can increase the impact strength of composites, while treated with titanate decrease it. However, different treat agent do not affect the tensile strength of PET/ M-POE/nano-CaC03 blends.7.Through different technology can prepare composites with different distribution of nano-CaCO3. It is indicated that the mechanical strength were decreased when nano-CaCO3 distributed in the PET matrix, however, when nano-CaCO3 distributed in the elastomer, that is formed so called "sandbag structure", not only increase the impact strength apparently, but also save the expensive elastomer and decline the cost of composites, which has greateconomical meaning.8. SEM photograph prove tht exist of sandbag structure, which would contribute to improve the mechanical properties and decline the cost of composites, meanwhile, this sandbag structure change the conventional view that the filler should be well-distributed in the polymer matrix.9. During the conte...
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