Styrene, copolymerization with drying oils

Waterman et al.7B described a method for the preparation of homogeneous copolymerization products of drying oils with styrene, according to which styrene vapours are brought into contact with the oils at temperatures of 220-28o°C. This method prevents the formation of high-molecular polystyrene and favours the chemical combination (copolymerization) of styrene with the oils79. 

Styrene-Modified Alkyd Resins. Styrene was first copolymerized with drying oils in the early 1940s. These binders had a substantially improved drying behavior and resistance to water and chemicals compared with untreated oils. The first patents for the production of styrenated alkyd resins were granted in the United Kingdom in 1942 [2.63]. Mixtures of styrene and a-methylstyrene are also used for a more reliable reaction vinyltoluene yields copolymers with improved thinnability in mineral spirit and pigment absorption. 

The polymer is amorphous and soluble. In this polymer, however, the side groups are rigid and they restrict considerably the bending and coiling of the polymer chains. Except at high molecular weights (unsuitable for paints), polystyrene is therefore weak and brittle, and styrene copolymers (sometimes styrene is copolymerized with drying oils and alkyds) are more suitable as paint resins. 

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