热塑性聚酰亚胺的热膨胀系数研究

利用静态热机械分析仪（TMA）测定了热塑性聚酰亚胺（TPI）注塑件的热膨胀系数α，考察了TPI的各向异性、尺寸稳定性以及添加不同填料对α的影响。结果表明：TPI存在着各向异性，且流向面的α最低。在正常的使用范围内，试样经历一个升降温循环后尺寸基本没发生变化。经消除热历史后，材料的α降低；类似地，热处理也能使。减小。在主链相同的TPI树脂中，加入玻纤、碳纤维等高强度、高热稳定性的填料有助于降低TPI的α。

Investigation on Coefficient of Thermal Expansion for Thermoplastic Polyimide

The coefficient of thermal expansion (CTE) of thermoplastic polyimide(TPI) was measured by means of thermal mechanical analyzer(TMA). The anisotropy, dimensional stability and the effects of different fillers on the CTE of TPI were also considered in the paper. The results showed that TPI exited anisotropy, and the CTE was the least at flow direction. The dimension almost did not have any change through an advance-decline temperature circle in the normal range of application. After relieving of the heat history, the CTE was decreased. The CTE would also be reduced via heat treating. The addition of some high strength and thermal stable fillers, such as fiber glass and carbon fiber, to TPI would contribute to decrease the CTE of TPI.