A novel chemical route for low-temperature curing of natural rubber using 2,4 dihydroxybenzaldehyde: improved thermal and tensile properties
Activation energy; Dihydroxybenzaldehyde; Latex; Low-temperature vulcanization; Natural rubber
A novel method for chemically curing natural rubber (NR) using 2,4-dihydroxybenzaldehyde (DHB) at low temperatures has been discovered. Adding varying amounts of DHB to NR increases the crosslinking between the NR molecular chains. The chemical reaction between NR molecular chains and DHB was confirmed through Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (NMR) spectra. From the thermogravimetric analysis (TGA), the thermal stability and activation energy of degradation were determined. The variation in glass transition temperature (Tg), as an indication of increased crosslink density, reducing the mobility of rubber chains, has been confirmed through differential scanning calorimetry (DSC). The addition of DHB to latex significantly enhanced the thermal stability of the rubber. An increase in the activation energy of 5.52% was observed upon the addition of 80mL DHB into NRL when compared to the uncured one. Furthermore, the tensile properties, in terms of tensile strength and modulus of elasticity of rubber, were drastically increased through DHB crosslinking. Tensile strength values of rubber were found to increase by reducing its elongation at break due to the formation of crosslinks between the macromolecular chains. NR cured with 80mL DHB exhibited superior tensile and thermal properties among the series of cured samples. By adding 80mL of DHB, the tensile strength increased by 390% and the elongation at break decreased by 10%. The advantage of this curing method is that, it is an effective technique for crosslinking NR directly from NR latex at comparatively low temperature. Graphical abstract: (Figure presented.) Iran Polymer and Petrochemical Institute 2024.
Raosaheb B.V.; Adeppa A.; Aralihalli S.; Kalkornsurapranee E.; Tuljittraporn A.; Chuaybamrung A.; Vijayashankar A.V.; Johns J.
Iranian Polymer Journal (English Edition), Vol-33, No. 7, pp. 915-925.
Springer Science and Business Media Deutschland GmbH
Raosaheb B.V., Research Center, Department of Physics, Rajarajeswari College of Engineering, Bangalore, India; Adeppa A., Department of Aeronautical Engineering, ACS College of Engineering, Bangalore, India; Aralihalli S., Department of Chemistry, Rajarajeswari College of Engineering, Bangalore, India; Kalkornsurapranee E., Division of Physical Sciences, Faculty of Science, Prince of Songkla University, Hat-Yai, Thailand; Tuljittraporn A., Division of Physical Sciences, Faculty of Science, Prince of Songkla University, Hat-Yai, Thailand; Chuaybamrung A., Division of Physical Sciences, Faculty of Science, Prince of Songkla University, Hat-Yai, Thailand; Vijayashankar A.V., Department of Sciences and Humanities, School of Engineering and Technology, CHRIST-Deemed to be University, Bangalore, 560074, India; Johns J., Research Center, Department of Physics, Rajarajeswari College of Engineering, Bangalore, India