Sorbic Acid-Modified Soybean Oil: A Promising Biobased Molecular Platform for Sustainable Thermosetting Resins

In this article, the synthesis of a fully biobased molecular platform for thermosetting resins, namely sorbated epoxidized soybean oil (SESO), starting from sorbic acid (SA), and epoxidized soybean oil (ESO), is reported. The chemical structure of SESO is deeply characterized by spectroscopic and molecular analysis. The isothermal thermogravimetric analysis indicated that SA exhibited extremely lower volatility than acrylic acid (AA), which suggests that SA could be used as a green and safe alternative to AA overcoming issues related to AA volatility and toxicity that can be experienced during AA manipulation. Several SESO-based thermosetting resins are obtained after the curing process performed by thermal treatment in the presence of a radical initiator. SESO shows complete curing after 6 h, faster than acrylated ESO (AESO), along with a good copolymerization ability with several reactive comonomers, such as styrene, myrcene, and pentaerythritol tetraacrylate, producing resins with similar mechanical (Young's modulus ranging from 6 to 1160 MPa) and thermal (glass transition temperature ranging from 17 to 61 °C) properties and superior biobased content to those AESO-based. The successful synthesis of SESO offers the opportunity to use SA as an environmentally friendly alternative to AA in the synthesis of green thermosets.