Polyfunctional phytic acid-based reactive diluent for UV-curable coating with improved flame-retardant performance and toughness

The shortcomings of oligomer resin, including its high viscosity, easy brittleness and lack of flame-retardant performance, obviously limit the application fields of the related coatings. Herein, a UV-curable polyfunctional biomass-based diluent (PAGMA) is conveniently and effectively synthesized by grafting glycidyl methacrylate onto phytic acid. The structural characterization of PAGMA is identified by FT-IR and H-1 NMR tests. Moreover, PAGMA diluent is mixed with UV-curable epoxidized soybean oil-based acrylic resin (ESO-based resin), and the influences of PAGMA on the viscosity of ESO-based resin, the mechanical property and the flame-retardant efficiency of the related films are systemically researched. All results demonstrate that the viscosity of composite resin (R-2 resin) with 20 wt% PAGMA reduces by 39.2% compared with that of ESO-based resin. And the toughness of the cured film (F-2 film) prepared by R-2 resin achieves about 1.18 MJ.m(-3), which is 2.26 times as large as the cured film prepared without PAGMA (F-0 film). Furthermore, the limiting oxygen index value of F-2 film improves by 31.2% compared with that of F-0 film, and the F-2 film can self-extinguish after being ignited. Thus, the prepared polyfunctional biomass diluent can be applied to UV-curable coatings to decline the coating viscosity and enhance the comprehensive properties of coating films, which assists in broadening the application fields of UV-curable materials, especially in fire prevention.

Automated summary

In this study, a polyfunctional biomass-based diluent (PAGMA) was successfully synthesized and applied to UV-curable coatings. The results demonstrated that PAGMA effectively reduced the viscosity of the coatings, improved the toughness and flame-retardant performance of the films. This research is of great significance in broadening the application fields of UV-curable materials, especially in fire prevention.