Synthesis and effectiveness of low styrene emission agents for unsaturated polyester

Abstract

The aim of this work is to synthesize linear and branched reactive molecules for use as low styrene emission (LSE) additives for unsaturated polyester (UPE). Maleinization reaction of primary alcohols was a specific way to synthesize the linear types of molecules. In this reaction, stearyl alcohol, PEG (2000), isooctyl alcohol, 1,5- pentanediol, PEG (400) mono-oleate and octylphenol ethoxylate were used as the primary alcohol source. Ring opening reaction of epoxidized soybean oil (ESO) with unsaturated acid groups was used to synthesize the branched types of molecules. Monostearoyl maleate, monomethyl maleate and oleic acid adducted epoxidized soybean oil and acrylated epoxidized soybean oil were used as branched types of LSE molecules. The structural analyses of the products were be done with 1H-NMR and IR spectroscopy. To examine industrial usefulness of the additives, styrene emission test and interlaminar adhesion test were be applied to the molecules synthesized according to AS/NZS 4585.1 and AS/NZS 4585.2 test procedures. In the styrene emission test, the amount of styrene evaporation was calculated by weighing the styrene lost from UPE resin mixture containing curing agents and LSE additive (%1 w/w based on polyester resin) during curing. In the interlaminar adhesion test, two ply laminates were prepared with chopped glass mat and UPE resin, curing agents and LSE additive. The force (N) required for delamination was measured as the interlaminar adhesion. For the comparison of LSE additives with blank and commercial additives, the results obtained were reported as a combination in a success factor S defined as; S= Interlaminar adhesion force (N) / Styrene emission (g/m2). The best three additives were monostearoyl maleate, monomethyl maleate adducted epoxidized soybean oil and peantane bismaleate. The styrene emission results of these additive were orderly 85 g/m2, 92 g/m2 and 96 g/m2. The interlaminar adhesion test results of these additives were orderly 40 N, 37 N and 28 N.