Simultaneous Interpenetrating Networks Based on Vernonia Oil Polyesters and Polystyrene: II. A Comparison of the Reactivities of Vernonia Oil and Castor Oil Toward the Formation of Polyesters

Abstract

Triglyceride oils such as linseed, oitica, tall, castor, and tung have long been used in varnishes, alkyds and other coating formulations. These days, new polymers based on such oils represent an alternative approach to reducing the dependence on petrochemical derivatives (1–7). Triglyceride oils can be polymerized to form interpenetrating polymer networks, IPN’s. An IPN may be defined as a combination of two polymers in network form, at least one of which is polymerized and/or cross-linked in the immediate presence of the other (3). The IPN’s of the present study are simultaneous interpenetrating networks, SIN’s. This involves the mixing of two monomers or prepolymers in an early stage of their reaction, followed by the formation of both networks. The reactions proceed simultaneously, through independent mechanisms, i.e. step growth and chain growth. Recently, experimental oils from potential new oil seed crops were investigated. In particular, naturally epoxidized vernonia oil, as well as chemically epoxidized linseed, crambe, lunaria, and lesquerella oils were used (2,4–6). Vernonia oil comes from a wild plant native to Kenya, Africa. The synthesis and characterization of vernonia oil SIN’s formed the first paper in this series (5).