Pineapple Fiber Hybrids Prepared by the Fusion of radiation-induced Graft Polymerization and Kabachnik-Fields three-component Reaction (RIGP-KF3CR)
The fusion of multicomponent reactions and polymer chemistry allows the synthesis of polymeric materials that contain special classes of molecules that are otherwise difficult to produce. In this study, a locally available nonwoven fabric composed of pineapple fibers and polylactic acid (piñatex) was modified by radiation-induced graft polymerization (RIGP) of vanillin methacrylate, a lignin-derived monomer. RIGP yielded organic hybrids made from a natural, renewable, and biodegradable substrate, and surface aldehyde groups from vanillin. The grafted fabric was prepared by gamma pre-irradiation at 50 kGy, exhibiting an increasing degree of grafting with increasing reaction time and monomer concentration. Post-polymerization modification carried out using Kabachnik-Fields three-component reaction (KF3CR) enabled the immobilization of amine and phosphite moieties on the fabric. FTIR, SEM-EDS and XPS analysis of 8 amine and phosphite combinations showed the presence of the corresponding elements and functional groups, indicating successful surface functionalization through RIGP-KF3CR. All modified natural fibers-based fabrics displayed enhanced thermal stability without obvious radiation degradation effects. Synthesized natural fibers contain α-aminophosphonate pendants which may be useful in the selective adsorption and recovery of industry valuable metals.