Synthesis of Soybean Oil Biomass Main Chain Poly(Acrylic Acid)-Poly(ɛ-Caprolactone) Based Heterograft Copolymer by Simultaneous Photo-Induced Metal-Free ATRP and Ring-Opening Polymerizations.

A photo-induced and completely metal catalyst-free synthetic pathway is proposed for the preparation of bio-based heterograft copolymer based on poly(acrylic acid) (PAA) and poly(ɛ-caprolactone) (PCL) pendant groups on the soybean oil (SBO) backbone (PAA-SBO-PCL). For this purpose, the SBO possessing primary hydroxyl and bromide functionalities (Br-SBO-OH) is prepared from epoxidized soybean oil (ESBO) by ring-opening reaction catalyzed by hydrochloric acid. The photo-induced metal-free atom transfer radical and ring-opening photopolymerizations (PIMF-ATRP and PIMF-ROP) of tertiary butyl acrylate (t-BA) and ɛ-CL monomersare concurrently performed on the Br-SBO-OH bifunctional macro photo-initiator without affecting each other, using perylene as an organic photo-catalyst (λ= 400–500 nm). The t-BA groups of resulting bio-based PtBA-SBO-PCL is hydrolyzed into acrylic acid moieties via acidolysis to achieve the ultimate PAA-SBO-PCL. Spectroscopic, chromatographic, wettability and thermal investigations such as FT-IR, ¹H-NMR, GPC, WCA, TGA and DSC analyses indicate that both the required intermediates and the targeted polymers are successfully synthesized, as well as the conversion of t-BA groups to acrylic acid units. Thus, this efficient and most importantly green and sustainable process that can be enabled to production of a variety of SBO-based heterograft copolymers could greatly expand the potential applications of widely used polymers as advanced materials. [ABSTRACT FROM AUTHOR]