以聚己内酰胺(PA6)和1-溴正十六烷为原料, 利用N-烷基化方法制备了具有不同烷基取代度的N-十六烷基聚己内酰胺(PA6C16)。 采用DSC和FTIR方法研究了具有不同烷基取代度的PA6C16的热转变行为。 DSC结果表明N-十六烷基聚己内酰胺的十六烷基侧链可以结晶, 且低取代度的N-十六烷基聚己内酰胺(PA6C16-L)侧链结晶的熔点高于高取代度的N-十六烷基聚己内酰胺(PA6C16-H)。 红外光谱结果表明, PA6C16-L侧链的亚甲基呈正交晶堆积, 而PA6C16-H的侧链亚甲基则呈六方晶堆积。 变温红外光谱结果显示, 伴随着侧链结晶的熔融, PA6C16-H的主链构象发生明显改变, 而PA6C16-L主链的构象则未显示出明显改变。

N-hexadecylated polycaprolactam (PA6) comb-like polymers (PA6C16) with different alkylation degree, were synthesized using the method of N-alkylation reaction. The thermal transition behavior of these polymers were characterized by a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). DSC results indicated that the hexadecyl side chain can crystallize. Furthermore, the melting point of the hexadecyl side chain crystallization of the sample with high alkylation degree(PA6C16-H) is lower than that of sample with lower alkylation degree(PA6C16-L). FT-IR spectroscopic results showed that the methylene groups of the hexadecyl side chain of PA6C16-L tend to crystallize in orthorhombic form, while the methylene groups of the hexadecyl side chain of PA6C16-H tend to be packed into hexagonal form. Variable temperature IR spectroscopic results revealed that accompanying the melting of the side chain crystallization, the backbones of PA6C16-H undergo a conformation transition, while the conformation of backbones of PA6C16-L shows no obvious transition.