Simultaneous improvement of mechanical and fire retardant properties of synthesised biodegradable guar gum-g-poly(butyl acrylate)/montmorillonite nanocomposite

A novel multicomponent biopolymer based nanocomposite was synthesised via graft copolymerization of butyl acrylate (BA) onto guar gum (GG) and montmorillonite (MMT) by using ammonium persulfate (APS) as a free radical initiator, in the presence of N,N′-methylene bisacrylamide (MBA) as a crosslinking agent. BA had been grafted onto GG chains and the participation of -OH groups of MMT in polymerization reaction was confirmed by FTIR spectra. XRD and TEM observations revealed that MMT was exfoliated and uniformly dispersed in guar gum-g-poly (butyl acrylate) (GG-g-PBA) matrix. The resultant nanocomposite showed remarkably improved thermal stability and mechanical properties. In addition, the excellent fire retardancy of nanocomposite results from the formation of compact and continuous char which not only hinders the migration of volatile decomposition products out of polymer matrix but also provides barrier for heat transfer evaluated by limiting oxygen index (LOI) and cone calorimetry test. The biodegradation of nanocomposite has been carried out for better commercialization and environmental concern.