Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

Abstract

Maillard reaction in Natural Rubber (NR) latex was investigated by treating fresh NR latex with glutaraldehyde (C 5 H 8 O 2 ) in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and attenuated total reflection infrared (ATR-IR) spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C 5 H 8 O 2 concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msub><mml:mrow><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mn fontstyle="italic">0</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>), plasticity retention index (PRI), Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out.