Green Approaches To Engineer Tough Biobased Epoxies: A Review

Epoxy resins possess a variety of excellent properties including adhesion, mechanical performance, electrical insulation and chemical resistance; however cured epoxy resin is brittle and typically petroleum based. Rising concerns about depletion of nonrenewable resources and climate change have resulted in attempts to find green alternatives for petroleum based materials and mitigate greenhouse gas emissions. The present review is aimed to discuss green approaches to overcome epoxy resins brittleness and deal with ongoing research strategies to make tough biobased epoxies. First, the key toughening modifiers such as rubbers, thermoplastics, nanofillers, dendritic and block copolymers are briefly discussed and pros and cons of each method are presented. Then, the studies that followed green approaches are thoroughly reviewed. The utilization of epoxidized vegetable oils, biobased hyperbranched polymers and biobased copolymers in epoxy matrix are discussed. The challenges for commercialization of biobased modifiers are assessed and the present and prospective status of research and development of the tough biobased epoxies are explored.