|Rayas-duarte, Patricia - Oklahoma State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/24/2009
Publication Date: 9/24/2009
Citation: Mohamed, A., Rayas-Duarte, P., Finkenstadt, V.L. 2009. pMDI-Reinforced Compression-Molded PCL/Gluten: Thermomechanical Properties. Meeting Abstract.
Technical Abstract: Polycaprolactone (PCL) and vital wheat gluten or wheat flour composites were prepared and compatibilized with polymeric diphenylmethane diisocyanate (pMDI) by blending and compression-molding. The thermo-mechanical properties of the composites were determined by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Instron, while molecular interactions were assessed by Fourier-transform infrared spectroscopy (FTIR) analysis. After it was cooled down to -70ºC and heated to 150ºC, the glass transition (Tg) of blended neat PCL/pMDI emerged at -67ºC. Vital wheat gluten showed Tg at 63ºC, whereas no Tg was recorded for wheat flour. The 'Cp of PCL and gluten were 0.20 and 0.45 (J/g/ºC) respectively. Although Tg was unmistakable for either PCL and gluten, all composite exhibited one Tg, which is strong indication for interaction between PCL and the fillers. Several samples amongst the blended or compression-molded composites exhibited no Tg signifying another confirmation for interaction. The 'H of the endothermic (melting) and the exothermic (crystallization) for PCL was decreased as the percentage of gluten or flour increased, while the overall 'H was higher for all composites compared to the theoretical value. The presence of pMDI appeared to strengthen the mechanical properties of the composites by mostly interacting with the filler (gluten or flour) and not as much with PCL. The FTIR analysis ruled out any non-covalent interaction between PCL, pMDI, or the fillers, but proposed the occurrence of physical interactions.