In-situ surface modification of cellulose nanofibril with poly(butyl acrylate)

ObjectiveCellulose nanofibril (CNF) is a promising strengthener but is used limitedly since its poor compatibility with organic materials. The graft polymerization of butyl acrylate (BA) via in-situ emulsion polymerization of CNF is adopted to modify its compatibility.

MethodThe conditions were optimized to induce the grafting yield of the PBA chains on the surface of CNF. FTIR, XRD, TEM, TGA, XPS and SEM-EDS were used to characterize the PBA-g-CNF, the compatibility of PBA-g-CNF and poly(lactic acid) (PLA) was characterized by SEM.

ResultThe results indicated that PBA-g-CNF showed the IR adsorption peak at wavenumber of 1 734. The crystallinity index of PBA-g-CNF was 48%, which was decreased compared with that of CNF (61%). The diameter of nanofibrils increased from 50 nm to 80−100 nm. The maximum degradation temperature of PBA-g-CNF increased by 14 ℃ compared with that of CNF. The C/O ratios of PBA-g-CNF and CNF were 3.76 and 1.89, respectively. C and O element were dispersed uniformly in PBA-g-CNF and CNF. The tensile fracture surface of PBA-g-CNF/PLA composite films showed tough character.

ConclusionCellulose nanofibril was succesfully modified by poly(butyl acrylate), and the modification process was mainly occured on the surface of CNF. The PBA-g-CNF showed good interfacial compatibility with poly(lactic acid).