Synthesis and characterization of carboxymethylcellulose and methyl methacrylate graft copolymers

Purpose - The purpose of this paper is to synthesise carboxymethylcellulose and methyl methacrylate graft copolymers (CMC-g-PMMA), which is used as an effective additive, for reinforcing the rice-hull-cement composite. Design/methodology/approach - Various CMC-g-PMMA copolymers were synthesised at different reaction temperatures, pH values of reaction solution and the dosages of monomer and initiator (potassium persulphate). The copolymers were characterised by Fourier transforms infrared (FT-IR) spectra, thermal analysis (thermogravimetric and differential scanning calorimeter), X-ray diffractometry (XRD) and scanning electron microscopy. Findings - An optimal CMC-g-PMMA copolymer is obtained. For synthesis of the CMC-g-PMMA, the optimal reaction temperature is 80 C and pH value is 9. FT-IR test of CMC-g-PMMA confirmed the existence of a chemical link between carboxymethylcellulose (CMC) and methyl methacrylate (MMA). The content of initiator has little effect on the reaction for synthesising the graft copolymer. Thermal analysis indicates the occurrence of graft reaction in CMC and MMA. XRD test proved that the chains of the graft copolymer can enlarge the proportion of the amorphous regions of CMC. Adding MMA has damage effect on the crystallisation. Research limitations/implications - Since the results of this paper are obtained from the laboratory experiments, further research should be conducted for evaluating the performances of this copolymer in practical application. Practical implications - The mechanical test of the rice-hull-cement composite proved that CMC-g-PMMA is an effective additive for reinforcing the rice-hull-cement composite. The synthesis of CMC-g-PMMA provides a new alternative for modifying cellulose derivatives. Originality/value - The CMC-g-PMMA obtained in this paper is a new kind of effective agent. It can reinforce the rice-hull-cement composite and expands the application of the composite in building industries.