| The demand for pressure sensitive adhesives (PSA) has been increasing over the last several years. Pressure sensitive adhesives are almost indispensable in everyday life as they are used for labels, tapes, films, and other specialty adhesive applications. These materials are derived from petroleum reserves and as their use increases, an alternative source of these materials becomes more important. To alleviate this dependency of petroleum, it is desirable to investigate the synthesis of these adhesives from a renewable resource, such as plant oils. Plant oils are triglyceride esters of fatty acids which vary in chain length and functionality. The goal of this research was to develop a polymer from a fatty acid methyl ester that displays PSA properties and has the potential to be used in a successful PSA formulation.; The basis for the materials synthesized and characterized in this research project is acrylated oleic methyl ester (AOME). This monomer is synthesized with two separate reactions. First, the oleic methyl ester starting material is epoxidized and then acrylated to form the final monomer, AOME. This monomer, which can readily participate in a free radical polymerization reaction, was used in a water-based emulsion system. Two different water-based emulsion polymerization techniques, conventional and miniemulsion, were developed as methods for synthesizing high molecular weight polymers.; Conventional emulsion polymerization required a high level of surfactant (15 wt.%), as well as 18 hours of reaction to obtain 90% monomer conversion. The resulting polymer has a weight average molecular weight of approximately 106 g/mol. The peel energies of adhesives developed from this technique range from 60 to 210 J/m2, depending on the polymer composition.; Miniemulsion polymerization requires only 2 wt.% surfactant and 1 hour of reaction to have nearly complete monomer conversion. The polymer has a weight average molecular weight of approximately 107 g/mol. The peel energies of these miniemulsion adhesives range from 100 to 370 J/ 2. PSAs developed from plant oil using miniemulsion polymerization display properties that are consistent with current petroleum-based PSAs. |
