CHAPTER 8: Development of Bio-based Unsaturated Polyester Resins from Natural Oils or their Derivates

This chapter reports the development of novel oil-based unsaturated polyester resins (UPRs) from plant oils or their derivates. First, a new tung oil (TO)-based macromonomer named “tung oil pentaerythritol glyceride maleate” (TOPERMA) was synthesized. Second, dicyclopentadiene-terminated UPR (DCPD-UPR) was modified by TO via an intermolecular Diels–Alder reaction during the later stage of melt polycondensation. Third, a highly functionalized castor oil product composed of castor oil pentaerythritol glyceride maleate (COPERMA) was employed to fabricate a partially bio-based UPR through blending it with petroleum-based UPR. The obtained TOPERMA and COPERMA monomers and TO-modified DCPD-UPR polymers were characterized by FT-IR, ¹H-NMR, ESI-MS, and GPC. The physical, thermal, and mechanical properties of the prepared oil-based UPRs were carefully studied. The structure–property relationship, especially the effects of phase separation and cross-link density on the mechanical properties, was also investigated. These oil-based UPR polymer materials show promise as an alternative to replace their corresponding petroleum-based materials.