Graft modification of deproteinized natural rubber latex with acrylonitrile and its self-healing property

Abstract

"The copolymer of deproteinized natural rubber (DPNR) grafted acrylonitrile (AN) and acrylic acid (AA) [DPNR-g-P(AN-co-AA)] was synthesized by emulsion grafting copolymerization, using DPNR as matrix, AN and AA as monomers in the initiation system of tert-butyl hydroperoxide and tetra-ethylenepentamine. The grafting of AN and AA monomers was verified by infrared spectroscopy and nuclear magnetic resonance spectroscopy, and the effects of total monomers amount and m(AN) / m(AA) on the mechanical properties of modified DPNR were studied, as well as the effect of healing conditions on its self-healing property. The results showed that under the conditions of a total monomer amount of 10 phr (in terms of dry rubber mass) and m(AN) / m(AA) of 10/1, the maximum tensile strength and elongation at break of DPNR-g-P(AN-co-AA) were 9.22 MPa and 1 365%, respectively, which were 376% and 133% of the initial DPNR. In addition, the hydrogen bond interaction between polyacrylic acid segments in the system enabled DPNR-g-P(AN-co-AA) to have excellent self-healing property, reaching a self-healing efficiency of 75.3% after 2 h of healing at 50 ℃. "

Keywords

• deproteinized natural rubber
• acrylonitrile
• acrylic acid
• emulsion graft copolymerization
• mechanical property
• hydrogen bond self-hea-ling