Unsaturated polyester resins (UPR) and vinyl ester resins (VER) are widely used
thermosetting polymers for fiber reinforced composites. The global UPR market is
approximately a 5,000 kilo ton business and is experiencing continued growth. These
resins typically are mixed with styrene (in amounts up to 50%) as a reactive diluent
before being cured by a free radical polymerization. Styrene however, has significant
disadvantages owing to health, safety, and environmental concerns.
The Clean Air Act Amendments of 1990 lists styrene as a hazardous air pollutant and
occupational exposure to styrene is regulated by the Occupational Safety and Health
Administration (OSHA). Also, effective April 2016, The California Office of
Environmental Health Hazard Assessment (OEHHA) added styrene as a carcinogen to
the Proposition 65 list. Furthermore, styrene is also derived from petroleum, which is a
This invention is a biobased, environmentally friendly alternative to styrene. It is a
monomer called methacrylated vanillyl alcohol (MVA) which is prepared from a vanillin
precursor. Because it has a low viscosity at room temperature, it can be used as a
reactive diluent to lower the viscosity of UPR and VER systems. It can also polymerize
into a highly crosslinked thermosetting polymer. For example, MVA homo-polymerizes
into plastic with a glass transition temperature of about 130°C, while polystyrene has a
glass transition temperature of just 100°C.
Vanillin is a naturally occurring chemical (extracted from vanilla beans, and widely used
in flavoring food). However, vanillin is also a very attractive feedstock for bio-based
chemicals and polymers because it can be mass-produced from lignin.
The resulting MVA is a low-viscosity liquid at room temperature which in contrast to
previous studies that showed methacrylated vanillyl (MV) is solid at room temperature.
Polymers from MVA have demonstrated greater storage moduli, higher glass transition
temperatures, and thermal resistance than those from MV. Thus, this new monomer is a
promising bio-based reactive diluent candidate for unsaturated polyester resins and vinyl esters which can replace styrene.