Tuning of Final Performances of Soybean Oil–Based Polymer Nanocomposites: Effect of Styryl/Oil Functionalized Intercalant of Montmorillonite Reinforcer

Abstract

Abstract Bio-based polymeric nanocomposites were prepared via polymerization of a monomer mixture of acrylated epoxidized soybean oil (AESO) and styrene in the presence of organophilic montmorillonite (MMT) clay by in-situ free-radical polymerization technique. MMT clay was rendered organophilic by a styryl/oil functionalized intercalant which is compatible with the two matrices and able to participate in the polymerization/crosslinking reaction. The presence of styryl group in the intercalant is also thought to be an original solution to the drawback mentioned in the literature arising from higher amount of small styrene monomer molecules in the clay galleries than larger AESO molecules at high clay loadings. The current design of the interclant is expected to allow polymer molecules grown from both AESO and styrene monomers inside the clay galleries and also from edges/surfaces of the silicate layers. In this study, a special attention was paid to the enhancement of both thermal and mechanical properites of AESO-based nanocomposites via usage of the compatible and reactive intercalant for MMT modification. The resultant nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of increased nanoclay loading in thermal and mechanical properties was investigated by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The nanocomposite materials exhibited improved thermal stability and dynamic mechanical properties as compared to neat polymer. The nanocomposite with exfoliation dominant structural morphology showed the highest storage modulus around Tg which is about 480% higher than that of neat AESOPS, even with a clay content as low as 3 wt%.