摘要
利用呋喃环侧基与单烯化合物所发生的Diels-Alder(DA)环加成反应,大幅度降低呋喃环在共聚物中的含量,从而制备出空气氛下稳定性较好的二氧化碳共聚物.研究发现DA反应的环加成程度越高,呋喃甲基缩水甘油醚/二氧化碳共聚物(PFGEC)的空气稳定性越好,当环加成程度超过70%时,可以得到稳定产物.DA反应条件对环加成程度影响较大,以N-苯基马来酰亚胺为例,最高环加成程度可达84.1%.此外,还发现DA反应在一定的温度下存在一定的可逆性,环加成产物在100℃左右可快速发生解离,即发生r-DA反应.
Diels-Alder（DA） reaction between N-phenyl maleimide and the pendant furan ring of the CO2 and furfuryl glycidyl ether copolymer（PFGEC） was employed for stabilization of PFGEC by reducing the amount of furan ring and introducing bulky groups into PFGEC.The stability of the product was enhanced by increasing the cyclization degree,the PFGEC with cyclization degree above 70% was air stable.Optimal reaction conditions were obtained,taking the N-phenyl maleimide as an example,cyclization degree as high as 84.1% was realized when the DA reaction was carried out in dimethyl carbonate at 60℃ for 24 h with molar ratio of N-phenyl maleimide to furan ring of 3∶1.The DA reaction was endothermal reaction,raising reaction temperature generally can raise cyclization degree,however,DA reaction was also a reversible process,when the temperature was high enough,reverse reaction（r-DA） existed,e.g.,when the DA product of PFGEC with cyclization degree of 72.1% was heated in dimethyl sulfoixde solution at 100℃ for 10 min,the cyclization degree decreased to 40.4%,indicating that the r-DA reaction proceeded quite fast at temperatures above 100℃.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2011年第11期1336-1340,共5页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号51021003)资助项目
