Thermal studies on dry bonding adhesive system for potential rubber article applications

• Published in: Journal of adhesion science and technology 2020-02, Vol.34 (3), p.233-245
• Main Authors: Dhanalakshmi, J., Vijayakumar, C. T.
• Format: Article
• Language: English
• Subjects: Adhesive bonding; Chemical bonds; Curing; DSC; Formaldehyde resins; Fourier transforms; hexamethoxymethylmelamine; Organic chemistry; Quinones; Resorcinol-formaldehyde resin; Rubber; Stability analysis; TGA; Thermal stability
• ISSN: 0169-4243; 1568-5616
• DOI: 10.1080/01694243.2019.1663700

Resorcinol formaldehyde resin (R1) and Hexamethoxymethylmelamine (HMMM) are extensively used as methylene acceptor and donor respectively in rubber compounding. This dry bonding system is used by most of the tire manufacturers. Detailed investigations on the chemistry of the dry bonding systems are scarce. Differential Scanning Calorimetric (DSC) investigations have been carried out for pure R1, pure HMMM and R1-HMMM blends (80:20, 60:40, 50:50, 40:60 and 20:80 weight ratio) and found that the thermal curing is taking place within a temperature span of 75 °C for materials having lower loading of HMMM and the curing is starting at around 135 °C. The study of the thermal stability of the materials using Thermogravimetric analyzer (TGA) indicates that the polymer from the blend is thermally more stable compared to the neat resin R1. The Fourier Transform Infrared Spectroscopic (FTIR) studies of these materials provide ample evidence for the formation of quinone methide structures during the reaction of R1 and HMMM.