低相对分子质量聚异丁烯热降解制备遥爪聚异丁烯

Telechelic polyisobutylene prepared by pyrolyzing low molecular weight polyisobutylene

高温时将LMPIB[低Mn(数均相对分子质量)聚异丁烯]热降解,用黏数测定产物的Mn,用碘量法测定产物的双键含量,用红外光谱(FT-IR)法和核磁共振碳谱(13C-NMR)法分析产物的分子结构,并研究了反应条件对产物双键官能度的影响。结果表明:当温度≥285℃时,LMPIB降解并生成了不饱和β-末端双键,提高了LMPIB的双键官能度;经315℃反应1.00 h后,产物的双键官能度达到1.57,n(末端α-双键)∶n(末端β-双键)=1∶3,并得到含α-、β-末端双键的遥爪齐聚物与含β-末端双键的齐聚物的混合物,n(遥爪齐聚物)∶n(单官能度齐聚物)≈1∶2。

The LMPIB[low Mn（number average molecular weight）polyisobutylene] was degraded at high temperature,then the Mnor double bond contents of the product were determined by viscosity number or iodine volume method,the molecular structure of the product was analyzed by infrared spectroscopy（FT-IR）and13C-nuclear magnetic resonance（13C-NMR）methods,and the influences of reaction conditions on functionality of double bond were investigated. The results showed that the double bond functionality of LMPIB was increased because the β- terminal unsaturated double bond was generated after degrading LMPIB when temperature was no less than 285 ℃. The double bond functionality and molar ratio of n（α-terminal double bond）∶n（β-terminal double bond）were 1.57 and 1∶3 in pyrolysis product,and the mixture of telechelic oligomer containing α- β-terminal doublebond and oligomer containing β-terminal double bond was obtained,their molar ratio was about 1∶2 when reaction time and temperature were 1.00 h and 315 ℃ respectively.