High Tg catalyst-free self-healing vitrimer derived from turpentine and its application in glass fiber reinforced composites

Conventional glass fiber reinforced composites (GFRCs) are usually difficult to degrade and the matrix usually exhibit low T_g. To address this dilemma, a degradable catalyst-free self-healing vitrimer matrix with a high T_g was fabricated using turpentine-derived terpene maleic acid (TMA) as a curing agent and epoxidized menthane diamine (EMDA) with a tertiary amine structure as an epoxy resin. Due to the introduction of a rigid terpene ring skeleton of turpentine, EMDA−TMA vitrimer exhibits a T_g of up to 201.8°C. Due to the tertiary amine groups in the EMDA−TMA, the vitrimer can achieve self-healing and recycling properties by dynamic transesterification reaction without the addition of catalysts. More importantly, the EMDA−TMA−GF composite prepared using EMDA−TMA vitrimer as a matrix also shows a high T_g (223.6°C), and excellent mechanical properties. In addition, under the synergistic action of potassium hydroxide (KOH) and ethanolamine (EA), the EMDA−TMA−GF composite can be rapidly degraded by a KOH/EA solution to realize non-destructive recovery of glass fibers.