Study on Chemical Decomposition and Repolymerization Process of FRP for Recycling

用几种固化剂固化制备了几种环氧树脂预聚体。用硝酸溶液对其进行化学分解。研究了环氧树脂预聚体和固化剂的分解产物与化学结构的关系。双酚F型环氧树脂与甲二胺固化是回收环氧树脂的最佳组合。用4mol/l硝酸溶液在80℃下分解150h。然后用乙酸乙酯从硝酸溶液中提取分解产物。将分解产物加入25wt%的环氧树脂预聚体中，用邻苯二甲酸酐固化。固化后的环氧树脂的弯曲强度是不含萃取物的环氧树脂的1.5倍，拉伸强度是不含萃取物的环氧树脂的4倍。差示扫描量热分析结果表明，环氧树脂与萃取物的化学结构均一。…提高了热稳定性由于玻璃化转变温度提高了约18℃，因此添加了更多的萃取物。化学分析结果表明，萃取物中胺基团的存在加速了固化反应，从而提高了树脂的交联度。以双酚F型环氧树脂和四缩水甘油二氨基二苯基甲烷(TGDDM)固化的双酚F型树脂为基质树脂，制备了玻璃纤维增强塑料。玻璃钢也可以用类似的方法进行分解。玻璃钢基质树脂的分解时间与纯树脂的分解时间基本相同。基质树脂完全消失，玻璃纤维可以回收。从硝酸溶液中提取分解产物。将提取物加入预聚体中，用邻苯二甲酸酐固化。萃取物含量在15wt%以下时固化效果较好，弯曲强度有所提高。将三种玻璃纤维浸泡在硝酸溶液中。E-玻璃纤维的通用性表明，纤维溶解，强度明显下降。另一方面，作为化学用途的C-玻璃纤维和作为机械用途的T-玻璃纤维没有明显的降解。研究表明，C、T玻璃纤维可以回收再用作增强纤维。较少

Some kinds of epoxy resins prepolymer cured with some kinds of curing agents were prepared. They were chemically decomposed by nitric acid solution. The relation between the decomposed products and chemical structure of epoxy resin prepolymer and curing agents were investigated. Bisphenol F type epoxy resin cured with menthanediamine was the optimum combination in order to recycle epoxy resins. The epoxy resin was decomposed by 4 mol/1 nitric acid solution at 80 ℃ for 150 hours. Then decomposed product was extracted by ethyl acetate from the nitric acid solution. The decomposed product was added to the epoxy resin prepolymer at 25 wt% and cured with phthalic anhydride. The cured epoxy resin showed that the flexural strength was 1.5 times, the tensile strength was 4 times with respect to the epoxy resin containing no extract. The results of differential scanning calorimetry indicated the homogeneity of the chemical structure of the epoxy resin with extract. Thermal stability improved by … More adding extract because the glass transition temperature increased about 18℃. The results of chemical analysis suggested the possibility of the increase of the crosslink density due to the acceleration of curing reaction by amine group in the extract.Glass fiber reinforced plastics were fabricated by using bisphenol F type epoxy resin cured with tetraglycidyldiaminodiphenylmethane (TGDDM) as a matrix resin. The FRP could be decomposed by similar method mentioned above. The decomposition time of matrix resin of FRP was almost the same as that of neat resin. The matrix resin completely disappeared and glass fiber could be recovered. The decomposed product was extracted from the nitric acid solution. The extract was added to prepolymer and cured with phthalic anhydride. The epoxy resin was well cured at the content of extract below 15wt% and the flexural strength increased. Three kinds of galss fiber were immersed in nitric acid solution. E-glass fiber as general purposes indicated that the fiber dissolved and the strength decreased remarkably. 0n the other hand, C-glass fiber as chemical purposes and T-glass fiber as mechanical purposes showed no significant degradation. It was suggested that C-and T-glass fiber could be recovered and reused as reinforcing fibers. Less