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Influence of functional groups on properties of styrene grafted NR using glutaraldehyde as curing agent
Author(s) -
Lehman Nussana,
YungAoon Wanida,
Songtipya Ladawan,
Johns Jobish,
Saetung Nitinart,
Kalkornsurapranee Ekwipoo
Publication year - 2019
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.21700
Subject(s) - thermogravimetric analysis , thermal stability , materials science , ultimate tensile strength , curing (chemistry) , polymerization , polymer chemistry , polystyrene , natural rubber , glutaraldehyde , styrene , copolymer , vulcanization , emulsion polymerization , methacrylate , dynamic mechanical analysis , composite material , chemistry , polymer , organic chemistry
Natural rubber grafted polystyrene (NR‐ g ‐PS) and natural rubber grafted polystyrene‐co‐methyl methacrylate (NR‐ g ‐P(S‐ co ‐MMA)) were prepared by emulsion polymerization technique using tert ‐BuHP‐TEPA as a redox initiator to improve the thermal and mechanical stability of NR. Additional peaks appear in the Fourier‐transform infrared spectra at 695 and 1,732 cm −1 confirms the formation of graft polymerization. The existence of functional groups on the grafted NR was also clearly confirmed from the morphology obtained from transmission electron microscopy analysis. The effect of curing on the mechanical and thermal properties of grafted NR has also been studied. Glutaraldehyde was used as the curing agent for the grafted and ungrafted NRs throughout the entire course of investigation. It was found that curing of grafted NR samples enhanced tensile strength, modulus, hardness, and thermal stability. Grafted NR showed the tensile strength values of 12 and 17 MPa for NR‐ g ‐PS and NR‐ g ‐P(S‐ co ‐MMA), respectively. Enhancement in thermal stability of NR was confirmend from the activation energy of degradation calculated based on thermogravimetric analyzer. The value of activation energy for NR (135.13 kJ/mol) was found to be increased to 147.89 kJ/mol (NR‐ g ‐PS) and 151.6 kJ/mol (NR‐ g ‐P(S‐ co ‐MMA)). The overall properties of NR have been strongly affected by the interaction and chain bundling between functional groups present in the grafted copolymer and the unsaturated chains in its structure. J. VINYL ADDIT. TECHNOL., 25:339–346, 2019. © 2019 Society of Plastics Engineers