PA6/CaCl_2复合物的络合机理研究

通过负离子淤浆聚合制备了高相对黏度的聚酰胺6(PA6)粉末料,将其加入氯化钙甲酸溶液中制备不同的PA6/CaCl2单位链节摩尔比络合溶液.采用X射线光电子能谱(XPS)、红外分析方法研究了PA6/CaCl2复合物的络合机理.结果表明,复合物中钙原子与聚酰胺6分子链上的羰基氧原子发生配位作用,破坏了PA6本身的氢键,释放出自由NH,而氯离子则与NH形成氢键.同时通过电导率测试推测氯化钙与酰胺键之间的配合形式为四配位或者六配位.

COMPLEXATION MECHANISM OF POLYAMIDE 6/CALCIUM CHLORIDE

Polyamide 6(PA6) powder with high relative viscosity of 22.47 was prepared via anionic slurry polymerization,and then different PA6 gels were gained by dissolving PA6 powder in formic acid using calcium chloride (CaCl2 ) as complex agent.X-ray photoelectron spectroscopy (XPS ) was used to characterize the bonding energy of inside electrons of pure PA6,CaCl2 and PA6/CaCl2 complexes,and Fourier transform infrared spectroscopy (FTIR)was performed to analyze the changes of the wave number of NH,amide Ⅰ and amide Ⅱ related to hydrogen bond in PA6/CaCl2 complexes.Based on the experiment results,a complexation mechanism was proposed to explain the reaction between amide group and CaCl2.Calcium cations coordinated with the oxygen atom of carbonyl group,which weakened the hydrogen bonding between the molecular chains of PA6 and released the free N—H group,so the N—H group coordinated with chloride anions to form the hydrogen bonding.There was no complexation between calcium cations and the nitrogen atom as the mole ratio of calcium chloride to the unit of amide group in PA6 was 0.2.The coordination number between CaCl2 and the amide groups was predicted to be four or six by conductivity measurements.