热塑性聚酰亚胺及其改性材料的热性能研究报告.doc

"材料物理"课程论文学生：梁东**： 20140530 学院：材料科学与工程学院专业年级： 2014级材料化学2班题目：热塑性聚酰亚胺及其改性材料的热性能研究指导教师：梁金教师评阅教师：　　梁金教师2016年6月摘要聚酰亚胺〔PI〕是一种高性能聚合物材料，具有优异的机械性能、电性能、耐辐射性能和耐热性能，广泛应用于航空航天、微电子和通讯等高技术领域，成为很有开展前景的材料之一但多数 PI 具有不溶不熔的特性，加工成型十分困难，一定程度上限制了其应用围，因此热塑性聚酰亚胺〔TPI〕成为开展方向之一TPI 不仅具有优异的综合性能，而且更易于加工，生产效率更高，在经济效益和环保方面都优于传统的热固性聚酰亚胺，成为人们开发研制的热点 TPI 可通过添加纤维提高力学性能，添加润滑剂提高耐磨性能，亦可与其它聚合物共混，使改性材料具有更优异的性能，应用于高科技领域目前，对 PI 及其改性材料性能的研究，大多数是关于力学性能和摩擦磨损性能，很少具体研究其热性能而聚酰亚胺的热性能，如玻璃化转变温度 Tg、热膨胀系数α是其应用于工业各领域重要的评价指标针对以上背景，本文首先测定了一种自主研发的 TPI 的玻璃化转变温度并通过改变分子量大小考察玻璃化转变温度与分子量的关系，及热处理温度和热处理时间对玻璃化转变温度的影响。

结果说明：玻璃化转变温度随数均分子量的增大而增加，采用 Kanig-Ueberreiter 方程关联玻璃化转变温度与数均分子量,其线性拟合度高；由于聚酰亚胺的构造特点——存在自由端基，在高温可发生固相热环化反响，相应其分子量随处理温度的升高和处理时间的延长而增大，表现为聚合物的玻璃化转变温度有所升高为了进一步提高 TPI 的性能，扩大其应用围，使其能在更加苛刻的环境下使用，TPI 的改性研究主要包括纤维增强的 TPI 树脂基复合材料及聚合物共混改性 TPI但由于高分子材料的热膨胀系数比纤维、瓷等无机材料要大得多，两者复合后，随温度的变化，热应力不仅使高分子和基材剥离，还会产生龟裂和翘曲，模压塑料则产生裂纹等另外高科技的开展，要求器械部的空间更小，对材料的热稳定和热膨胀性能提出了更高的要求因此，本文在上一步工作的根底上，选出一种分子量的 TPI 树脂，测定其注塑件的热膨胀系数及其各向异性和尺寸稳定性；并考察了所添加的填料种类对热膨胀系数的影响结果说明：TPI 存在着各向异性，且流向面的热膨胀系数低在正常的使用围，试样经历一个升降温循环后尺寸根本没发生变化消除热历史后，材料的热膨胀系数降低；类似地，热处理也能使热膨胀系数减小。

在主链一样的 TPI 树脂中，参加玻纤、碳纤等高强度、高热稳定性的填料有助于降低 TPI 的热膨胀系数对于共混改性的 TPI，主要用熔体流动速率仪研究了 TPI/聚醚醚酮〔PEEK〕共混物的流变性能，用差示扫描量热仪考察了共混物的相容性和热性能，用广角 * 射线衍射仪研究了共混物的形态和结晶性能结果说明：共混物的熔体流动指数随 PEEK 含量的降低和熔体温度的升高而增加；TPI/PEEK 共混物为不相容体系；随 TPI 含量的减小，共混体系中 PEEK 的结晶温度和熔点分别升高，而结晶度降低，* 射线衍射的结晶峰越来越明显，峰面积也随之增大为了与 PEEK/TPI 共混物进展比较，还考察了 PEEK 与 PEI 共混物的相容性和结晶性能等结果说明：PEEK/PEI 共混物完全相容，所有共混物均呈现一个玻璃化转变温度，且与组分的关系符合 Porch 方程；这是由于 PEEK 和 PEI 间的电荷转移相互作用占主导地位随 PEI 含量的增加，共混体系的熔点、结晶度、整体结晶速率和结晶能力均降低；而 PEEK 的结晶度呈现先增加后减小的趋势，当 PEI 质量分数为 50%时，到达最大关键词热塑性聚酰亚胺玻璃化转变温度热膨胀系数改性共混ABSTRACTPolyimides is an important high-performance polymers used in aircraft, microelectronics, munication fields and so on for their marked thermal-stability, e*cellent mechanical, electrical and radiation–resistance properties. However, many of these polyimides are insoluable and infusible, leading them impossible to process by the conventional methods, which has confined the widespread use of the polyimides. So the thermoplastic polyimides (TPI) are being one of the development directions. TPI preparation research has bee popular project in owing to they are not only provided outstanding prehensive properties, but also can be easily processed, with high production efficiency, and are better than thermosetting polyimides at economic effectiveness and environmental friendly. In order to improve TPI’s mechanical or tribological properties, the fibers and or lubricants are filled into the resin; another way is to make TPI blend with other polymers especially for application in high-tech fileds. At present, many research works on TPI posite materials are focused on the mechanical and tribological properties, rarely on the thermal properities. But the thermal properities of TPI, such as glass transition temperature (Tg) and coefficient of thermal e*pansion (CTE), are considered as the important inde*es as TPI is applied in industries. Based on above background, the Tg for TPI were measured in this paper, and the effects on Tg, such as molecular weight, heat treated temperature and heat treated time were also investigated. The results showed that Tg was increased with increase of the molecular weight, meanwhile the Kanig-Ueberreiter equation provided a good fit to Tg and number-average molecule weight. Due to the TPI structure feature which contained the free end group, solid therm-cyclization could be carried out at high temperature. Accordingly, the molecular weight and Tg are also increased with increase of the heat treated temperature and time. In order to e*tend the TPI application area especially in the rigoroussurroundings, the TPI had been modified by filling fiber and or mi*ing with other polymers. Because the CTE for polymer is larger than those of fiber and ceramic, the phase separation and thermal stress might be take place for their posite, as results, the crack and or distortion will ocurr with the change of temperature. Moreover, the thermal-stability and thermal e*pansion properties should be needed in the high-tech areas. The CTE of TPI resin with appropriate molecular weight was measured, and its anisotropy and dimensional stability were also determined by TMA. The effect of fillings on the CTE was further investigated in this work. The results showed that TPI e*isted anisotropy, and the CTE was the smallest at flow direction. The dimension almost did not take change in periods of temperature loop under its working temperature. As relieving of the heat history via heat treating, the CTE would be decreased. The CTE of posite could be decreased if the fillings such as glass fiber and carbon fiber with high strength and themal stability were added. The processability, patibility, thermal properities, morphologies and crystallization of the TPI/PEEK blends were investigated by means of melt flow inde*er, differential scanning cal。