以聚对苯二甲酰对苯二胺(PPTA)和1-溴正十六烷为原料, 利用N-烷基化方法合成了N-十六烷基聚对苯二甲酰对苯二胺(PPTAC16), 并采用DSC和FTIR方法进行了详细研究。 DSC结果表明PPTAC16存在侧链结晶行为, 但侧链结晶的完善程度低于正十六烷烃的结晶。 红外光谱结果表明, 烷基侧链结晶中亚甲基堆积的有序度低于正十六烷烃晶体, 亚甲基的构象中存在相当数量的旁式构象。 变温红外光谱结果表明随着温度的升高, 亚甲基的伸缩振动谱带和变角振动谱带的峰位发生突变, 说明侧链结晶的熔融； 该结果与DSC测试结果一致。 另外, 伴随着十六烷基侧链结晶的熔融, PPTAC16的主链发生了一种不可逆的变化, 且熔融后的烷基侧链所处的状态与液态十六烷烃存在差别。

N-hexadecylated poly(p-phenylene terephthamide) (PPTA) comb-like polymers (PPTAC16), which are composed of PPTA backbone and hexadecyl side chains, were prepared by method of N-alkylation reaction. The molecular structure and thermal transition behavior of PPTAC16 were characterized by a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) technique. DSC results indicated that the crystallization of hexadecyl side chains, and the side chain crystallization is less perfect than that of n-hexadecane crystal. IR results showed that the ordered degree of the packing of CH2 group in the side chain crystallization is lower than that of n-hexadecane crystal. Variable temperature IR spectroscopic results revealed that the stretching vibration and bending vibration bands of methylene group experience an abrupt change with increasing of temperature which indicate the melting of the side chain crystallization, furthermore the main chain of PPTAC16 was found to undergo an irreversible change accompanying the melting of the alkyl side chain crystallization. And the molten state of CH2 group in the hexadecyl of PPTAC16 is different from that of liquid n-hexadecane.