Khairil Juhanni Abd Karim

A Review of the Properties and Applications of Poly (Methyl Methacrylate) (PMMA)

Advances in the use of poly (methyl methacrylate) (PMMA) have opened up a wide range of applications in the field of nanotechnology. The knowledge of the properties of PMMA has contributed a lot to the recent boosts in the synthesis, modification, and applications of the polymer. However, there is a need to condense these developments in the form of an article for better understanding and easy access. This review highlights the fundamental physical properties of PMMA, coupled with experimental evidence of its essential chemistry, such as solubility, hydrolysis, grafting, combustion reactions, reactions with amines, and thermal decomposition. The recent developments in the applications of PMMA in biomedical, optical, solar, sensors, battery electrolytes, nanotechnology, viscosity, pneumatic actuation, molecular separations, and polymer conductivity were also revealed.

Preparation of methacrylamide-functionalized crosslinked chitosan by free radical polymerization for the removal of lead ions.

A new poly(methacrylamide) grafted crosslinked chitosan was prepared for removal of lead, Pb(II) ion from aqueous solution. Crosslinked chitosan, in beads form, was grafted with methacrylamide (MAm) using ammonium persulfate (APS) as free radical initiator. Evidence of grafting was determined by comparing FTIR, TGA, SEM and (13)C NMR analyses of chitosan and graft copolymer. The optimal conditions for grafting reaction were as follow: crosslinked chitosan beads (1g), MAm (17.62×10(-1)M), APS (2.63×10(-1)M), reaction time (3h) and temperature (60°C). The modified chitosan bead was then used in laboratory batch experiments to evaluate the removal of Pb(II) ion from water samples. The Langmuir and Freundlich adsorption models were also applied to describe the equilibrium isotherms. The results revealed that the adsorption of Pb(II) ions onto the beads fitted very well with the Langmuir model with the maximum capacity (qmax) of 250mgg(-1).

Equilibrium, kinetic and mechanism studies of Cu(II) and Cd(II) ions adsorption by modified chitosan beads

In this study, the Cu(II) and Cd(II) ions removal behavior of crosslinked chitosan beads grafted poly(methacrylamide) (abbreviated as crosslinked chitosan-g-PMAm) from single metal ion solutions was investigated. The modified chitosan beads presented a remarkable improvement in acid resistance. The batch experiments demonstrated that pH of solution played a significant role in adsorption. It was found that the adsorption of Cu(II) and Cd(II) were optimum at pH 4 and pH 5, respectively. The maximum adsorption capacities for Cu(II) and Cd(II) based on Langmuir equation were 140.9 mg g-1 and 178.6 mg g-1, respectively. Pseudo-second order gave a better fit for adsorption data with respect to linearity coefficients than pseudo-first order suggesting that chemisorption or electron transfer is the dominant mechanism of the metal ions onto crosslinked chitosan-g-PMAm. In addition, X-ray photoelectron spectroscopy (XPS) investigations revealed that adsorption of both metal ions took place on the surfaces of crosslinked chitosan-g-PMAm by chelation through CNH2, CO and CO groups. Overall, the modified chitosan has proved a promising adsorbent for removal of metal ions.

Influence of poly(methyl methacrylate) grafted multiwalled carbon nanotubes on the mechanical and thermal properties of natural rubber nanocomposites

In this study, we describe the preparation and characterization of natural rubber nanocomposites filled with poly (methyl methacrylate) grafted multiwalled carbon nanotube. The use of various filler loadings (1, 2, 3, and 5 wt %) and melt blending method was employed. From the results, nanocomposite with 1 phr filler loading showed the optimal tensile strength of 4.92 MaP, while that of the carbon black N330 filled natural rubber with similar filler loading found to be 2.48 MaP. The nanocomposite with optimal tensile strength exhibited a good filler dispersion in the natural rubber matrix, which was depicted by the field emission scanning electron microscopy images. The thermal degradation temperature of the vulcanized neat natural rubber composite was increased from 380℃ to 462℃ with 1 phr filler loading. The polymer modified multiwalled carbon nanotube improved the mechanical and thermal properties of natural rubber, suggesting its potential as reinforcement filler in rubber industry.