废旧聚氨酯硬泡的解交联研究

摘要

采用二乙醇胺作为解交联剂,将废旧聚氨酯(WPUR)硬泡在HAAKF流变仪中进行化学降解,并采用傅里叶转换红外光谱(FTIR)、差示扫描量热分析和凝胶含量测试等分析手段,研究了解交联剂、加工温度和加工时间对降解产物结构的影响.结果表明,当WPUR硬泡与二乙醇胺质量比为10∶1时,随着加工温度的升高,WPUR硬泡的降解速率加快.当加工温度由170℃升到220℃,流变曲线达到平衡的时间从30 min缩短到9 min,WPUR硬泡的凝胶含量由74.2%降到45.4%.FTIR分析证实了降解产物为带有氨基和羟基的解交联的PUR.在200℃下,当WPUR硬泡与二乙醇胺质量比为5∶1时,把加工时间进一步延长至30 min,则WPUR硬泡的凝胶含量由91.4%下降到3.6%,降解产物的玻璃化转变温度由75℃下降至36℃,间接证明WPUR硬泡的交联结构已基本解除.%The waste polyurethane (WPUR) rigid foam was degraded with diethanolamine (DEA) in a HAAKE torque rheometer and the influence of processing temperature and processing time on structure of degraded products was studied by FTIR, DSC and Gel content analysis. The research results showed that with the processing temperature increased, the degradation rate of WPUR rigid foam accelerated. With the processing temperature increased from 170℃ to 220℃, the time when rheological torque reached the balance was decreased from 30 min to 9 min, the gel content of WPUR decreased from 74.2％ to 45.4％, and FTIR spectra showed that degraded WPUR with hydroxyl groups and amino groups was generated. When the process time increased to 30 min under 200℃,the gel content of WPUR decreased from 91.4％ to 3.6％, and glass transition temperature of the degraded WPUR decreased from 75℃ to 36℃ in DSC, which confirmed the disruption of the cross - linking structure of WPUR rigid foam.