Radiation Graft-Copolymerization of Ultrafine Fully Vulcanized Powdered Natural Rubber: Effects of Styrene and Acrylonitrile Contents on Thermal Stability

• Published in: Polymers Vol. 13; no. 19; p. 3447
• Main Authors: Rimdusit, Niratchaporn, Jubsilp, Chanchira, Mora, Phattarin, Hemvichian, Kasinee, Thuy, Tran Thi, Karagiannidis, Panagiotis, Rimdusit, Sarawut
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 08-10-2021; MDPI
• Subjects: Caustic soda; Copolymerization; Copolymers; Corrosion resistance; Crosslinking; Efficiency; electron beam vulcanization; Electron beams; Electron irradiation; Epoxy resins; graft copolymer; Graft copolymers; Impact strength; Latex; Mechanical properties; Monomers; Morphology; Natural rubber; natural rubber-graft-polyacrylonitrile; natural rubber-graft-polystyrene; Physical properties; Polyacrylonitrile; Polymer blends; Polymer matrix composites; Polystyrene resins; Radiation; Radiation dosage; Rubber; Solvents; Spectrum analysis; Spray drying; Structural stability; Styrenes; Thermal resistance; Thermal stability; ultrafine fully vulcanized powdered rubbers; Ultrafines; Thailand; Switzerland; Bangkok Thailand
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym13193447

Graft copolymers, deproteinized natural rubber-graft-polystyrene (DPNR-g-PS) and deproteinized natural rubber-graft-polyacrylonitrile (DPNR-g-PAN), were prepared by the grafting of styrene (St) or acrylonitrile (AN) monomers onto DPNR latex via emulsion copolymerization. Then, ultrafine fully vulcanized powdered natural rubbers (UFPNRs) were produced by electron beam irradiation of the graft copolymers in the presence of di-trimethylolpropane tetra-acrylate (DTMPTA) as a crosslinking agent and, subsequently, a fast spray drying process. The effects of St or AN monomer contents and the radiation doses on the chemical structure, thermal stability, and physical properties of the graft copolymers and UFPNRs were investigated. The results showed that solvent resistance and grafting efficiency of DPNR-g-PS and DPNR-g-PAN were enhanced with increasing monomer content. SEM morphology of the UFPNRs showed separated and much less agglomerated particles with an average size about 6 μm. Therefore, it is possible that the developed UFPNRs grafted copolymers with good solvent resistance and rather high thermal stability can be used easily as toughening modifiers for polymers and their composites.