Trehalose-incorporated organic-inorganic hybrid nanocomposites produced by thiol-ene photopolymerization

Thiol-ene photopolymerizations of isocyanurate-based trithiol (S3I)/mercaptopropyl-substituted random-type polysilsesquioxane (SQ), and allyl-etherified trehalose (AxT) with a degree of allylation x = 6 or 8, which was prepared by the reaction of alpha,alpha-D-trehalose and allyl bromide, produced trehalose-incorporated organic-inorganic hybrid nanocomposites (AxT-S3I/SQys) with an SQ content of y = 10 or 20 (wt%). All of the photo-cured hybrid films exhibited high transparencies to visible light. Fourier transform infrared spectroscopy (FT-IR) spectral analysis revealed that the thiol-ene photopolymerization proceeded almost to completion for all of the samples, except that some allyl groups remained for A8T-S3I/SQ20. The glass transition temperatures (T(g)s) and 5% weight loss temperatures (T(5)s) of AxT-S3I/SQys increased with increasing y values. Although the T-g of A6T-S3I/SQy, which had a hydrogen bonding interaction, was higher than that of A8T-S3I/SQy, the A6T-S3I/SQy T-5 was lower than the A8T-S3I/SQy T-5, which had a higher crosslinking density. The tensile strengths and moduli of all of the AxT-S3I/SQys, except for A8T-S3I/SQ20, markedly increased with increasing y values.