Biodegradability of [pineapple leaf fibre-g-poly(n-butyl acrylate)]/silicate composite superabsorbents

摘要

Natural fibre composites have been prepared by grafting hydrophobic monomer [n-butyl acrylate (BA)] onto chemically modified pineapple leaf fibre (PALF) using a complex initiating system [Cu (II) SO_4/EDTA/ammonium persulphate (APS)] in an aqueous medium without and with additives [sodium silicate (SS)] and N,N'-methylenebisacrylamide (MBA) as crosslinking agent. The polymerization reaction has been studied at varying temperature, duration, and Cu(II), EDTA, APS and BA concentrations. The overall activation energy of grafting is found to be 19.04 kJ mol and the optimum time period for the reaction is 3h. The chemically modified PALF, crosslinked PALF-g-PBA copolymer and (crosslinked PALF-g-PBA)/SS composites so obtained have been characterized by FT-IR and their morphology studied by scanning electron microscopy. The thermal behaviour and tensile properties of the samples have been studied and compared with their biodegradation and water absorption capacities. It is observed that the composites show more water uptake capacity than the copolymers, making them suitable for use as superabsorbent natural fibre. These composite superabsorbents show lower biodegradability in both sludge water and soil as well as by using cultured microorganisms than the copolymer alone.