ADR4370S扩链改性PBT及其复合材料的性能研究

发布时间：2019-03-08 19:41

【摘要】：聚对苯二甲酸丁二醇酯(PBT)因具有优异的力学性能、耐化学腐蚀、优良的耐湿热老化性能和介电性,被广泛应用于电子电器、汽车和机械行业以及光纤光缆等领域。但PBT仍有许多不足之处,如缺口冲击强度低、易翘曲等。尤其国产的PBT树脂,因分子量低、特性黏度小、力学性能差等原因,不能满足光纤级材料的要求。本文采用化学扩链、增韧、增强等方法对PBT进行改性。首先,采用环氧扩链剂ADR4370S对PBT进行扩链改性,研究不同扩链剂用量对体系的结构与性能的影响以及扩链体系的力学性能和热稳定性能。结果表明,ADR4370S的添加,使PBT分子结构发生变化,产生梳型支化结构,有效提高了PBT的熔体黏度和熔体强度,体系的力学性能得到明显改善,热稳定性与Tg变化不大。但ADR4370S过量时,PBT扩链产物发生溶胶凝胶转变。其次,测试PBT扩链产物的特性黏度,并研究体系的非等温结晶行为。结果表明,当ADR4370S用量为1.50 wt%时,扩链产物的特性黏度[η]从1.061dL/g提高至1.486 dL/g,粘均分子量为从35117提高至51681,且与PA1.25扩链体系相当。.同时,ADR4370S有利于提高PBT的结晶温度。Mo法能较好的描述PBT及其扩链体系的非等温结晶过程,而Jeziorny法只能较好地描述体系的非等温结晶的初期过程。ADR4370S可降低体系的结晶活化能,但对PBT的基体成核机理和生长方式基本没有影响。再次,先将ADR4370S熔融分散于POE中,再与PBT树脂进行增韧扩链。探讨扩链剂的加入对共混体系中PBT的结构与性能影响。结果表明,环氧扩链剂与POE并不发生反应,但能够有效的对PBT进行扩链改性,使得复合材料的储能模量、损耗模量和复数黏度提高,拉伸强度、缺口冲击强度和弯曲模量也得到改善,但扩链反应的进行也使得体系产生了支化结构。最后,以经1.25 wt%ADR4370S扩链改性后的PBT树脂为基体,OMMT为无机纳米填充材料,通过熔融插层法制备纳米复合材料,研究OMMT的添加量对PA1.25体系的相形态和性能的影响。结果表明,OMMT含量较少时,复合材料的熔体黏度和模量均降低,但拉伸强度和弯曲模量均提高。当OMMT含量为0.5 wt%时,材料的结晶温度最高,半结晶时间最小,且缺口冲击强度最大。
[Abstract]:The polybutylene terephthalate (PBT) has excellent mechanical property, chemical corrosion resistance, excellent heat and heat aging resistance and dielectric property, and is widely applied to the fields of electronic equipment, automobile and machinery industry, optical fiber optical cable and the like. However, PBT still has many disadvantages, such as low notch impact strength, easy to warp, and the like. In particular, the domestic PBT resin can not meet the requirements of the fiber-grade material due to low molecular weight, low intrinsic viscosity, poor mechanical property and the like. In this paper, PBT is modified by chemical chain extension, toughening and strengthening. First, the effect of different chain extender on the structure and performance of the system and the mechanical properties and thermal stability of the chain extender were studied by using the epoxy chain extender (ADR4370S). The results show that the addition of the ADR4370S makes the molecular structure of the PBT be changed, and the comb-type branching structure is produced, the melt viscosity and the melt strength of the PBT are effectively improved, the mechanical property of the system is obviously improved, and the thermal stability and the Tg change are not large. However, when the ADR4370S is excessive, a sol-gel transition occurs in the PBT chain extension. Secondly, the intrinsic viscosity of the product of PBT chain extension was tested and the non-isothermal crystallization behavior of the system was studied. The results show that, when the amount of ADR4370S is 1.50 wt%, the intrinsic viscosity of the chain extension product is increased from 1.061 dL/ g to 1.486 dL/ g, the viscosity average molecular weight is from 35117 to 51681, and the chain extension system is equivalent to that of the PA1.25 chain extension system. At the same time, the ADR4370S is beneficial to the improvement of the crystallization temperature of PBT. The non-isothermal crystallization process of PBT and its chain extension system can be well described by Mo method, and the Jeziorny method can only better describe the initial process of the non-isothermal crystallization of the system. The ADR4370S can reduce the crystallization activation energy of the system, but has no effect on the nucleation mechanism and the growth mode of the matrix of PBT. And then, the ADR4370S is melted and dispersed in the POE, and then the ADR4370S is toughened and chain-extended with the PBT resin. The effect of the addition of chain extender on the structure and properties of PBT in the blend system was discussed. The results show that the epoxy chain extender does not react with the POE, but can effectively chain-extend the PBT, so that the storage modulus, the loss modulus and the complex viscosity of the composite material are improved, the tensile strength, the notch impact strength and the bending modulus are also improved, But the extension chain reaction is carried out so that the system produces a branched structure. In the end, the effect of the addition of OMMT on the phase morphology and performance of the PA1.25 system was studied by using the PBT resin modified with the chain extension of 1.25 wt% of the ADR4370S as the matrix and the OMMT as the inorganic nano-filling material. The results showed that the melt viscosity and the modulus of the composites decreased when the content of OMMT was small, but the tensile strength and flexural modulus were all improved. When the content of OMMT is 0.5 wt%, the crystallization temperature of the material is the highest, the semi-crystallization time is the minimum, and the notch impact strength is the largest.
【学位授予单位】：福建师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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