Synthesis and characterization of styrene-co-divinylbenzene-graft-linseed oil by free radical polymerization

Abstract

A variety of opaque white to light yellow polymeric material have been prepared by two methods, one copolymerization of styrene (ST), divinylbenzene (DVB), and grafting of linseed oil (LIN), and the second involves the copolymerization of the same comonomers with pre-reacted (with initiator) linseed oil. All of the reactant mixtures in different concentrations start to solidify at 100°C and give rise to a solid crosslinked polymer at 130°C. These polymeric materials contain approximately 30 to 74% of crosslinked materials. Their 1H NMR spectra indicate that the polymeric samples contain both soft oily and hard aromatic segments. The insoluble material left after soxhlet extraction contains finely distributed micropores. The heat deflection temperatures (HDT) of the polymer samples range from 26 to 44°C. The glass transition temperature for different linseed oil polymer samples ranges from 66 to 147°C (from dynamic mechanical analysis) and 158 to 182°C (from differential scanning calorimetry). The crosslinking density of samples ranges from 35.0 to 6.01•104 mol/m3. Irrespective of methods, the storage modulus decreases with increasing oil content in the copolymers. The polymers prepared by the first method show minimum swelling in saline water and maximum swelling in tetrahydrofuran. On the other hand, the polymers from the second method show maximum swelling in alkaline solution and a minimum in acidic solution.

Keywords

• Biopolymers, biocomposites
• linseed oil
• dynamic mechanical analysis
• transition temperature
• swelling ratio