【作者】 崔正；

【导师】 张胜； 陈宇；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2010， 硕士

【摘要】 论文研究了基础树脂粘度、成核剂和结晶促进剂的种类与含量、阻燃剂及其体系、玻璃纤维对PET结晶行为的影响。选定了13种成核剂和8种结晶促进剂,发现滑石粉的成核效果和聚丁二酸丁二醇酯(PBS)的结晶促进效果较好；确定了阻燃增强PET工程塑料的工艺配方。所得阻燃增强PET工程塑料的阻燃性能达V-0级,拉伸强度为145MPa,弯曲强度为212MPa,冲击强度为8.0kJ／m2,热变形温度为223℃,与国外同类产品性能接近,在国内处于领先地位。在配方研究的基础上,进行了结晶理论研究：利用差示扫描量热仪(DSC)对结晶PET的升温与降温过程进行测试,详细研究PET在成核剂、结晶促进剂作用下的结晶行为,并通过偏光显微镜(POM)、广角X射线衍射(WAXS)研究结晶PET的微观形态,初步探讨成核剂、结晶促进剂的作用机理。结果发现,各类成核剂的加入均不同程度地提高了PET的结晶温度(Tc),加快其结晶速率,使PET的晶粒增多,且细化均一。其中以滑石粉的成核效果最优,当添加量为0.5%时可使结晶温度提高12.54℃,且随降温速率的减小结晶完善程度得以提高；利用非等温结晶动力学方程证实了滑石粉对PET结晶行为的影响。此外,结合力学性能和热性能测试对滑石粉、有机蒙脱土、稀土化合物、进口成核剂(P250)、山梨醇类(BQ-88)、受阻酚磷酸酯盐类(MD-NA-28)、苯甲酸钠等成核剂的作用机理进行了分析探讨,其中多以诱导PET降解来加快成核结晶速率。结晶促进剂的加入可不同程度地降低PET的冷结晶温度(Tcc),其中PBS与聚乙二醇(PEG-1500)质量比为1：1的混合物当添加量为3%时,可使PET的Tcc降低17.5℃。PBS的促进机理主要是通过其自身的快速结晶成核诱导PET大分子成核。研究发现阻燃剂及阻燃协效剂具有成核作用；而玻璃纤维作为增强材料对PET的结晶成核无明显贡献。在上述研究基础上,进行了阻燃增强PET工程塑料配方优化的探讨。结果发现,阻燃剂、阻燃协效剂在满足材料的阻燃性能的同时还具有成核作用；成核剂、结晶促进剂在不同阻燃增强PET体系中的作用不及其在纯PET中显著；配方优化应考虑助剂兼效,实现一剂多效。更多还原

【Abstract】 Effects of the viscosity of the resin, the type and content of nucleating agents and the nucleating promoters, the flame retardants, glass fiber on the crystallization behavior of PET have been investigated. Talc and polysuccinate (PBS) were chosen from thirteen nucleating agents and eight nucleating promoters respectively. The process formulation of enhanced flame retardant PET was determined. The fire performance of PET can reach up to V-0 with the tensile strength of 145MPa, flexural strength of 212MPa, the impact strength of 8.0 kJ/m2 and heat distortion temperature of 223℃, which can compete with similar foreign products.The effect of nucleating agents and nucleating promoters on the crystallization behavior has been studied by using differential scanning calorimetry (DSC), and morphology of PET was observed by polarized light microscopy (POM) and wide-angle X-ray diffraction (WAXS). The mechanisms of both nucleation and nucleating promotion were proposed.The results show that the crystallization temperature Tc of PET has been increased in varying degrees by the addition of various nucleating agents, the crystallization rate has been speeded up. Among them, talc powder has the best nucleating effect, which can increase the crystallization temperature by 12.54℃with 0.5%addition and the crystallization can be improved with the cooling rate reduction; non-isothermal crystallization kinetics equations also was used to confirm the effect of talc powder on the crystallization of PET. In addition, the function of talc, montmorillonite, rare earth compounds, import product (P250), sorbitol (BQ-88), hindered phenol phosphate salts (MD-NA-28), sodium benzoate, the nucleating mechanism were analyzed and discussed according to the mechanical properties and molecular structure.The nucleating promoters can reduce cold crystallization temperature Tcc by different degrees, the Tcc of PET which added with 3%of the mixture of PBS and polyethylene glycol (PEG-1500) with the mass ratio of 1:1 can be reduced by 17.5℃. PBS as a better nucleating promoter is due to its faster crystallization rate.Flame retardants and the synergistic flame retardant can also promote nucleation; however, the effect of glass fibre on the crystallization behavior of PET is minimal.The principle of enhanced flame retardant PET engineering plastic formulation has been discussed. The results show that the flame retardants can also be used as nucleating agents, the effects of nucleating agents and nucleating promoters on different enhanced flame retardant PET systems are not as significant as that on pure PET; the efficiency of additives in formulation should be considered.更多还原