Investigation of N-Hexadecylated Polycaprolactam by Infrared Spectroscopy
KONG Lei1, ZHAO Ying1*, SHI Hai-feng2, WANG Du-jin1, XU Duan-fu1, WU Jin-guang3
1. Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China 2. Institute of Functional Fibers, College of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, China 3. College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
Abstract: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.
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