Fatigue crack growth behavior and morphological analysis of natural rubber compounds with varying particle size and structure of carbon black

• Published in: Polymer engineering and science Vol. 62; no. 3; pp. 743 - 757
• Main Authors: Chanda, Jagannath, Mishra, Nitish, Dolui, Tuhin, Ghosh, Prasenjit, Mukhopadhyay, Rabindra
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.03.2022; Society of Plastics Engineers, Inc; Blackwell Publishing Ltd
• Subjects: Analysis; Carbon; Carbon black; carbon black dispersion; Crack propagation; Crystallization; Cyclic loads; Fatigue; fatigue crack growth; Fatigue failure; Fatigue strength; Fatigue testing machines; Fracture mechanics; Materials; microscopic analysis; Natural rubber; natural rubber compounds; Particle size; Room temperature; Rubber; Stiffness; Strain analysis; Tear and Fatigue Analyzer; Wear resistance; India
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.25881

Carbon black (CB) is an essential ingredient of any rubber compound to achieve the desired strength, stiffness, wear, and fatigue resistance. Depending on the function of a tire component (tread, sidewall, apex, etc.), different types of CBs, varying in particle sizes and structures, are used. On prolonged exposure to cyclic loading, rubber compounds lose their strength due to mechanical fatigue. In this study, the fatigue crack growth (FCG) behavior of unfilled and CB‐filled natural rubber compounds is investigated with varying particle size and structure (N115, N134, N220, N234, N330, and N339). FCG properties have been measured using a Tear and Fatigue Analyzer under various strain levels and temperatures. Microscopic analysis revealed that compounds with lower particle size and high structure CB showed better distribution and dispersion of CB throughout the whole matrix. Lower particle size with higher surface area displayed superior FCG resistance compared to the higher particle size CB. FCG of above compounds has also been studied at three different temperatures such as room temperature (25°C), 70°C, and 100°C. Significant increase in FCG rate was observed with increase in temperature due to the thermo‐oxidative degradation and reduction of strain‐induced crystallization. This study aimed to capture fatigue crack growth (FCG) behavior of unfilled and carbon black–filled natural rubber compounds with varying particle size and structure (N115, N134, N220, N234, N330, and N339). FCG properties have been measured using a Tear and Fatigue Analyzer under various strains (15%, 20%, 25%, 30%, and 40%) and temperatures (25°C, 70°C, and 100°C).