(617d) Biobased Soft Crosslinked Polymer Films from Phenolic Acids

Polymer films derived from thiol-ene chemistry are attracting an increasing commercial interest, due to their ease of preparation and superior physical properties. These films are found in a variety of applications including floor coatings, wood coatings and adhesives. The thiol- and ene-containing monomer precursors to these films are traditionally derived from petroleum sources. As a result of the finite supply of petroleum and the environmental implication of petroleum processing, biobased sources are increasingly attractive alternatives. Thiol-ene polymer films were synthesized containing sustainable, plant-derived phenolic acids (allylated salicylic acid and 4-hydroxybenzoic acid) as substitutes to the traditional ene-bearing components. Salicylic acid and 4-hydroxybenzoic acid contain rigid aromatic rings, which are expected to contribute to mechanical strength of the resulting films. The network structure and physical properties of the crosslinked films were investigated. Allylated salicylic acid and 4-hydroxybenzoic acid differ in the relative placement of allyl groups. This work develops fundamental relationships between the molecular structure of the phenolic acids and the thermal and mechanical properties of the resulting polymer films. Such knowledge is an important first step toward the widespread implementation of biobased phenolic acids in thiol-ene polymer film applications.