Preparation and properties of natural rubber latex-g-modified cationic polyacrylamide copolymers and its palm oil absorbent

Abstract

The grafting of a modified cationic polyacrylamide (MCPAM) onto natural rubber (NR) latex to form a copolymer using potassium persulphate (K₂S₂O₈) to generate active radicals on both the NR particle surface as well as on the MCPAM molecules was confirmed by ATR-FTIR. The copolymers showed a marked ability to absorbe palm oil up to 10 g g⁻¹. First, the high molecular weight cationic polyacrylamide (CPAM) was reduced by using a combination of K₂S₂O₈ and hydrogen peroxide (H₂O₂) through thermal degradation. The molecular weight of the CPAM as determined by viscosity was about 4000 g mol⁻¹. It was then added to the NR latex in the presence of Terric16A16 at 60°C for 3 h and cast as a film on a glass plate to obtain the NR-g-PAM. In a water medium, the swelling ratio of the modified NR decreased as a function of the CPAM concentration. Also the thermal stability of the modified NR-g-PAM was higher than of the NR/PAM blend as confirmed by TGA. Finally, the ability of NR-g-MCPAM to absorb palm oil was investigated.