Synthesis of poly(propylene fumarate) by acylation of propylene glycol in the presence of a proton scavenger

To synthesize high molecular weight poly(propylene fumarate) (PPF), fumaryl chloride and propylene glycol were reacted in the presence of potassium ca rbonate, which serves as a proton scavenger. Transesterification of the res ulting low molecular weight oligomer led to a polymer with greater molecula r weight than those from previous reaction methods without requiring the us e of a catalyst. According to two-dimensional NMR, the backbone structure o f this polymer was as expected and contained no byproducts formed by acid c atalyzed addition across the fumarate double bond. Kinetic studies of the t ransesterification showed that the molecular weight reached a final M-n of 4900 (+/-700) and M-w of 9100 (+/-1300) after 16 h, while the polydispersit y index remained below 1.8 throughout the reaction. Thus the PPF synthesize d by the new method is of higher molecular weight and greater purity than o ur previously prepared material.