Hydrophobic modification of cellulose isolated from Agave angustifolia fibre by graft copolymerisation using methyl methacrylate

Graft copolymerisation of methyl methacrylate (MMA) onto Agave angustifolia was conducted with ceric ammonium nitrate (CAN) as the redox initiator. The maximum grafting efficiency was observed at CAN and MMA concentrations of 0.91 × 10−3 and 5.63 × 10−2 M, respectively, at 45 °C for 3 h reaction time. Four characteristic peaks at 2995, 1738, 1440, and 845 cm−1, attributed to PMMA, were found in the IR spectrum of grafted cellulose. The crystallinity index dropped from 0.74 to 0.46, while the thermal stability improved upon grafting. The water contact angle increased with grafting yield, indicating increased hydrophobicity of cellulose. SEM images showed the grafted cellulose to be enlarged and rougher. The changes in the physical nature of PMMA-grafted cellulose can be attributed to the PMMA grafting in the amorphous regions of cellulose, causing it to expand at the expense of the crystalline component.