Evaluation of Grafting Parameters of Styrene onto Alkaline Modified Sugarcane Bagasse using Fe2+/H2O2 and Fe2+/H2O2-N2H4 initiator systems and Characterization of the Hydrolyzed Grafted Polystyrene Chains

Abstract

Cellulose the most abundant natural fibre can be modified, via grafting with vinyl monomers, in homogenous or heterogeneous reaction medium. Therefore, the objective of this paper was to study the grafting parameters of styrene onto alkaline modified sugarcane bagasse using Fe²⁺/H₂O₂ and Fe²⁺/H₂O₂- N₂H₄ initiator systems and characterized the hydrolyzed grafted polystyrene chains for their viscometry and average molecular weight distributions using standard appropriate methods. The grafting parameters increases within 0.10-0.25 M styrene concentration in both initiator systems and initiator concentration within the range 1.0x10^-3 to 6.0x10^-3 for Fe²⁺/H₂O₂- N₂H₄ and 1.0x10^-3 to 9.0x10^-3 for Fe²⁺/H₂O₂ systems, albeit with higher values in the former system. These parameters decrease at higher monomer and initiator concentrations in both systems. The viscometry of hydrolyzed polystyrene chain prepared at optimum initiator concentrations and 0.10-0.30 M styrene concentration in both initiator systems are in the range (1.6416-4.5327 cP), (0.6416-3.5327 cP) and (73.2277-202.1927 cP) for relative, specific and inherent viscosities respectively, consistent with increases in activation energy of flow (1.24-5.30 KJmol^-1) and average viscosity molecular weights (307.92-565.79 gmol^-1) , these parameters decreases at higher monomer concentration in both initiator systems. The number and weight-average molecular weight distributions and polydispersity indices indicates that grafted polystyrene chains in Fe²⁺/H₂O₂ system are broader and more polydispersed than those for  Fe²⁺/H₂O₂- N₂H₄ initiator system. The results showed that the hydrazine enhanced initiator system was more effective for the copolymerization reaction with polystyrene polydispersity indices comparable to those of synthetic chain-growth polymers.