Unsaturated polyester resins for thermoset applications using renewable isosorbide as a component for property improvement

Unsaturated polyester (UPE) resins are used in a variety of thermosetting applications due to the reduced cost when compared to epoxy resins; however, UPE resins also have reduced thermomechanical performance. Investigating avenues to improve the performance of UPEs has led to the use of bio‐based starting materials as structural components of the synthesized prepolymers as a result of their advantageous structural features. Isosorbide, a compound derived from renewable feedstocks, has been utilized to provide additional stiffness from the diol component for novel unsaturated polyesters resins. These resins have been shown to possess T g 's (32−72°C) and storage moduli (540−2200 MPa) that are in the desired range for composite materials with viscosities (1.2−25 Pa s) amenable to a variety of liquid molding techniques.