New biosourced UV-curable coatings based on isosorbide
Isosorbide was involved in photopolymerisation as a green monomer for UV-curable coatings. French researchers modified this polyol by (meth)acryloyl chloride to obtain isosorbide di(meth)acrylate at a high yield in a one-step reaction.
Various (meth)acrylated derivative monomers integrating polycaprolactone and poly(tetramethylene glycol) segments (CAPDA, PEGDA) were obtained according to the same route with high yield. Crosslinked materials were obtained by intense UV irradiation, and the details of the photopolymerisation kinetics were determined via real-time FTIR.
Rigidity affects final conversion
The effect of the chemical structure of the monomer was investigated, and the rigidity of the monomer was found to be the main parameter impacting the final conversion and photopolymerisation rate. Isosorbide diacrylate (ISDA)-based materials were compared to PEGDA- and CAPDA-based materials and were found to have a higher glass transition temperature and moduli.
Proper mechanical properties
To increase the amount of biobased monomers in the formulations, mixtures of ISDA/PEGDA at various ratios were tested. Finally, UV-curing formulations from ISDA/PEGDA and ISDA/CAPDA were investigated with the addition of an adhesion promoter and were compared to “Ebecryl 525” (a polyester resin from Allnex). These formulations succeeded in more than 70% of the standard tests (abrasion, gloss, adhesion, deformation, and impact) and thus could be applied as coatings in various fields.
The study is published in: Progress in Organic Coatings, Volume 99, October 2016, Pages 393–399
