可化学回收的生物基环氧玻璃体

Chemical upcycling of degradable bio-based epoxy vitreous

采用生物基缩水甘油醚季戊四醇双缩香草醛环氧树脂(DEPVD)为原料,经商用二苯二硫醚胺固化剂(AFD)固化得到生物基环氧玻璃体(DEPVD-AFD)。利用核磁共振氢谱(1H-NMR)对DEPVD的结构进行了表征。通过红外光谱(FTIR)、示差扫描量热仪(DSC)、热重分析仪(TGA)、拉伸测试机、降解回收实验等手段对环氧树脂的固化过程和综合性能进行了表征。结果表明,树脂材料具有较好的力学性能、热稳定性及降解性能,其玻璃化转变温度为143℃,拉伸强度为87.0 MPa,杨氏模量约为2300 MPa,10%热失重温度为323℃。降解回收实验的结果表明,固化剂中含有的螺环缩醛结构赋予了环氧树脂可降解的特性。DEPVD-AFD能在H+浓度为0.1 mol/L的1,4-二氧六环溶液中完全降解(处理温度75℃,时间4 h),由于降解产物具有显著的溶解度差异,含有二苯二硫醚结构的高价值中间产物(DSS)可以通过水洗的方式进行简单高效的回收,DSS的FTIR和1H-NMR结果表明此中间产物具有明确的化学结构和较高的纯度,这种简单高效的回收方式有望为环氧玻璃体的化学回收铺平道路。

The bio-based glycidyl ether pentaerythritol divanillin epoxy resin(DEPVD)was used as raw material and cured with commercial diphenyldisulfide amine curing agent(AFD)to obtain the bio-based epoxy vitreous(DEPVD-AFD).The structure of DEPVD was characterized by 1H-NMR.The curing process and comprehensive properties of epoxy resin were characterized by FTIR,DSC,TGA,tensile testing machine,degradation recovery experiment,and other methods.The results indicated that the resin material had good mechanical properties,thermal stability and degradation properties,and its glass transition temperature,tensile strength,Young′s modulus and 10%thermogravimetric temperature was 143℃,87.0 MPa,2300 MPa and 323℃,respectively.The results of the degradation and recovery experiment showed that the spirocyclic acetal structure contained in the curing agent gived the epoxy resin degradable properties.The DEPVD-AFD could be completely degraded in 1,4-dioxane solution at an H+concentration of 0.1 mol/L(treatment temperature 75℃,time 4 h).Due to the significant solubility difference of degradation products,high-value intermediates(DSS)containing diphenyl disulfide structures could be recovered simply and efficiently by water washing,and the FTIR and 1H-NMR results of DSS showed that this intermediate had a clear chemical structure and high purity.This simple and efficient recycling method is expected to pave the way for the chemical recovery of epoxy vitreous.