The use of E-beam to optimize the properties of fatty acid-based polymers

Recently, the Federal EPA increased legislation to address hazardous emissions from composite manufacturing and repair by enacting new emission standards, which specifically target styrene as a regulated hazardous air pollutant. One method of reducing styrene emissions from vinyl ester (VE) resins is to replace some or all of the styrene with fatty acid-based monomers. Fatty acid monomers are ideal candidates because they are inexpensive, have low volatilities, and promote global sustainability. Thermal cure of these resins results in materials with fairly low T _g and moduli. E-beam cure has been found to increase T _g by 25°C and increase the modulus by 20%. FTIR analysis showed that these property improvements can be attributed to higher monomer conversion with E-beam relative to thermal cure. In addition, fatty acid monomers can be potentially used as a component in rubbery materials and elastomers. To test their ability to be used in these materials, fatty acid monomers were mixed with small amounts (<10%) of multi-functional monomers, such as VE and acrylated triglycerides. These polymers were very fragile when thermally cured. On the other hand, the resulting polymers were much tougher and had higher T _g and monomer conversions when cured via E-beam.