四甲基哌啶胺对PA6抗紫外光老化和热氧稳定性的影响

Influence of 4-amino-2,2,6,6-tetramethylpiperidine on the UV Light Aging and Thermal Oxidation Stability of PA6

在己内酰胺开环聚合过程中加入一定量的4-氨基-2,2,6,6-四甲基哌啶(四甲基哌啶胺),合成改性PA6树脂.研究了四甲基哌啶胺对PA6光稳定性、热氧稳定性和末端氨基含量的影响.结果表明:四甲基哌啶胺的加入能明显提高PA6的耐紫外光和热氧稳定性,空气氛围下的起始分解温度提高20℃左右,相对黏度明显下降;在185℃空气氛围下老化30 min,改性PA6相对黏度下降很少(四甲基哌啶胺含量为0.1%时,PA6的相对黏度不变),热氧稳定性得到明显改善.同时,PA6的末端氨基含量增加,加入量为0.2%时,末端氨基含量提高了19.7 mmol/kg.而四甲基哌啶胺对PA6的热稳定性、冷结晶温度和熔融温度影响不大.

A certain amount of 4-amino-2,2,6,6-tetramethylpiperidine（ 4-ATMP） was added in the ring-opening polymerization of caprolactam for the synthesis of a modified PA6 resin. The influence of 4-ATMP on the UVlight aging,thermal oxidation stability and terminal amino group content of the modified PA6 was investigated. The results showed that addition of 4-ATMP could significantly improve the stability of UVlight agingand thermal oxidation and increased the content of the terminal amino group. The initial decomposition temperature of the modified PA6 in air atmosphere was increased by about 20 ℃,the content of the terminal amino group was increased by 19. 7 mmol / kg（ 0. 2%4-ATMP） as compared to those of unmodified PA6. After aging in air at 185 ℃ for 30 min,the relative viscosity of the PA6 modified with 0. 1% 4-ATMP remained practically unchanged and the content of the amino group decreased by only 5%. Addition of 4-ATMP does not have any significant influence on the thermal stability,coldcrystallization temperature and the melting point.