Gökhan Çaylı

Renewable Polymeric Nanocomposite Synthesis Using Renewable Functionalized Soybean-Oil-Based Intercalant and Matrix

Completely bio-based and renewable polymeric nanocomposites have been prepared using an in situ polymerization technique in the presence of organically-modified montmorillonite (MMT) clays in different loading degrees. Acrylated epoxidized soybean oil (AESO) and styrene have been used as matrices, whereas modification of MMT has been done by using a new renewable soybean-oil-based intercalant, quarternized functionalized acrylated epoxidized soybean oil, which is the first renewable intercalant described in the literature. It was found that the above-mentioned intercalant could be successfully intercalated between the interlayer galleries of montmorillonite which is confirmed by X-ray diffraction (XRD) data and atomic force microscopy (AFM). The nanocomposite formation studies examined by both XRD and AFM showed that the desired exfoliated nanocomposite structures can be achieved with all nanofiller loadings. The resultant exfoliated nanocomposites were found to have significantly improved thermal stability and dynamic mechanical performance at very low loadings. The nanocomposites from both renewable intercalant and matrix offer a significant potential for new high-volume, low-cost applications.

Cross-Linkable Epoxidized Maleinated Castor Oil: A Renewable Resin Alternative to Unsaturated Polyesters

As an alternative resin to conventional synthetic unsaturated polyesters (UPEs), epoxidized maleinated castor oil (EMACO) was synthesized in two steps. For this purpose, castor oil was reacted with maleic anhydride at 70°C to obtain maleinated castor oil (MACO). Then, epoxidation of MACO was carried out by using a mixture of formic acid and hydrogen peroxide at 0–5°C. Then, the free carboxyl groups of the synthesized EMACO were further reacted with free epoxide groups of EMACO at 90°C. At the end of the reaction, an unsaturated polyester precursor-prepolymer was obtained (P-EMACO). FTIR and 1H NMR spectroscopic techniques were used to characterize the monomers synthesized. The P-EMACO was then mixed with styrene and cross-linked in the presence of AIBN at 50°C. Thermal and mechanical properties of the final cross-linked product were investigated by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) techniques. The degradation onset temperature of the material at which cross-linked X-EMACO loses 5% of its weight was found to be 209°C. Its dynamic and storage modulus at 25°C were determined as 72°C and 1.08 GPa, respectively. These results are higher than some of the different oil based polymers reported in the literature.