Shear Strength and Morphological Study of Polyurethane-OMMT Clay Nanocomposite Adhesive Derived from Vegetable Oil-Based Constituents

摘要

In the current work, we have synthesized vegetable oil-based polyurethane-OMMT clay nanocomposite (PUNC) adhesive with the incorporation of different wt% of organically modified nanoclay (1 to 5 wt%) into the biobased polyurethane (PU) matrix through in-situ polymerization process via ultrasonication method. At the initial stage, PU adhesive was prepared using polyol and partially biobased aliphatic isocyanate, wherein polyol was derived from the transesterified castor oil using ethylene glycol. The formation of PU and PUNC adhesive was confirmed using Fourier transform infrared (FTIR) spectroscopy analysis. The tensile strength of PU with different wt% of nanoclay was determined and the analysis showed that the loading of 3 wt% of nanoclay within the PU matrix showed better performance as compared to the others. Furthermore, shear strength of PU and PUNC (3 wt% nanoclay) adhesives were determined using lap shear test, in which PUNC adhesive showed higher adhesive strength at 70 degrees C. Subsequently, the dispersibility of OMMT nanoclay within the PU matrix along with exfoliation and amorphous structure was confirmed through wide angle X-ray diffractometer (WAXD) and transmission electron microscopy (TEM) analysis. The phase separation structure was analyzed using dynamic mechanical analysis (DMA). The analysis revealed that with the addition of organically modified nanoclay in the PU matrix, the glass transition temperature (T-g) of the damping curve was shifted towards higher temperature.