Toughened epoxy modified with phenol‐nonyl phenol based polymer

Abstract

PurposeTo evaluate the efficiency of modifying epoxy resin using phenol‐nonyl phenol based polymer (PNPF) for toughness improvement and optimise the results of such a modification.Design/methodology/approachFor effective toughening, various compositions were made by incorporating PNPF at different concentrations. The impact and adhesive strengths of the unmodified and modified epoxy networks were characterised.FindingsThe modification of epoxy resin using PNPF showed significant enhancement of impact and adhesive strengths over the unmodified one. The modification caused the formation of a chemical linkage between PNPF and resin which led not only to a phase separation, but also to formation of intrinsically strong chemical bonds across the PNPF phase/resin matrix interphase, which was the main cause of the improved impact and adhesive strengths. The optimum results were obtained at 10 phr (parts per 100 parts of epoxy resin) of modifier.Research limitations/implicationsThe modifier, PNPF, used in the present context was synthesised from phenol, nonyl phenol and formalin using oxalic acid as catalyst.Practical implicationsThe developed method provided a simple and practical solution to improving the toughness of a cured epoxy.Originality/valueThe method for enhancing toughness of a cured epoxy was novel and could find numerous applications in the surface coating and adhesive.