Improved performance of poly(lactic acid) nanocomposites with poly(butyl acrylate)-modified cellulose nanowhiskers

Abstract

Poly(butyl acrylate) (PBA) was grafted onto cellulose nanowhiskers (CNW) via transesterification in an ionic liquid and solution polymerization in water. Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, x-ray photoelectron spectroscopy, and x-ray diffraction were used to determine the structure and morphology of the PBA-modified CNW (CNW-g-PBA). Poly(lactic acid) (PLA)/CNW-g-PBA nanocomposites were prepared by solution casting. The inclusion of CNW-g-PBA significantly increased the composite strength, toughness, and thermal stability. The maximum tensile strength and elongation-at-break values were approximately 28% and 268%, respectively, higher than those of PLA. The fracture surface showed typical ductile fracture characteristics. The glass-transition temperature raised from 56.7 for PLA to 60.3°C for CNW-g-PBA (5 wt% PBA), and the crystallinity rose from 1.6% to 10.3%. These findings show that the modification of nanowhiskers increased their compatibility with, and dispersion in, PLA. These results show that a combination of surface-functionalized CNWs and PLA provides biocomposites with a broad range of applications, for example, in packaging and biomedical products. Highlights: CNW-g-PBA was prepared by transesterification and solution polymerization route. PLA/CNW-g-PBA exhibited strong and tough performance. Compatibility mechanism have been developed.