Correlations between natural rubber protein content and rapid predictions of rheological properties, compression set and hardness of rubber compound

• Published in: Journal of the Indian Chemical Society 2021-11, Vol.98 (11), p.100162, Article 100162
• Main Authors: Sadeghi, Masoumeh, Malekzadeh, Mercedeh, Taghvaei-Ganjali, Saeed, Motiee, Fereshteh
• Format: Article
• Language: English
• Subjects: Cure characteristics; Natural rubber; Physico-mechanical properties; Protein content; Rheological properties
• ISSN: 0019-4522
• DOI: 10.1016/j.jics.2021.100162

In this study the correlations between protein contents of different kinds of natural rubber were considered with rheological behavior, compression set and hardness of rubber compounds based on natural rubber. At the first stage, protein contents were obtained by Kjeldahl method and correlated with normalized absorbance of amine band in NR's attenuated total reflection Fourier transform infrared spectra and shown linear behavior. At the second stage, correlations between the protein contents obtained by the spectra were considered with rheological behavior, compression set and hardness of rubber compounds and shown second order fitting models. The introduced models were applied to predict these features in case studies. Results were shown that Mooney viscosity, torque difference, optimum cure time, scorch time, cure rate index and hardness can be predicted by lower than 10% while compression set can be estimated by lower than 20% error. This significant attitude is a nondestructive and fast technique that uses little quantity of NR for prediction of some NR based compounds properties, before compounding. [Display omitted] •Proteins have notable effects on NR based rubber compounds properties.•There are a linear correlation between protein content and FTIR amine absorbance.•Second order correlations are seen between the absorbance and compound properties.•Significant predictions for compound properties can obtained before compounding.•This new approach for prediction is an easy, quick and non-destructive technique.