Investigation on the Brill transition of polyamide 618

• 来源期刊: 中国高等学校学术文摘·化学
• 关键词: Brill transition polyamide 618 conformation triclinic pseudo-hexagonal
• 年，卷（期）: 2007,（1）
• 页码范围: 6-12
• 页数: 7页
• 语种: 英文

摘要

The Brill transition of even-even polyamide 618 was investigated using differential scanning calorimetry (DSC),temperature-dependent wide angle X-ray diffraction (WAXD)and Fourier transform infrared(FTIR).The X-ray diffraction results indicate that the melt-crystallized sample of polyamide 618 transforms from the triclinic unit cell to the pseudo-hexagonal phase in the range of 120-180℃.In this range,the thermograph of polyamide 618 presents a broad endothermal peak.From the FTIR spectra,it was found that during the transition process of polyamide 618,the intensity of the intra-sheet hydrogen bonds becomes weak.At the same time,the CH2-amide bonds twist,and the all-trans conformation of methylene sequences is disordered by inserting the gauche conformation.The CH2 segments are in a mobile state because of the enhanced stretching and twisting vibrations of the C-CO and C-N bonds.