Characterisation of cut and chip behaviour for NR, SBR and BR compounds with an instrumented laboratory device

ABSTRACT

Understanding the cut and chip (CC) effect in rubber is important for successful product development for tires used in off-road or poor road conditions and for other demanding applications of rubber. This research describes a laboratory testing method for characterising the CC fracture behaviour of rubber using a device that controls and records multiple applied loads and displacements during cyclic impact to the surface of a solid rubber specimen to mimic and quantify the CC damage experienced by tire tread compounds. To study the capabilities of the instrument, three model compounds were studied that are based on carbon black reinforced compounds of common elastomers used in tire treads: natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). These polymers have well-established CC tendencies in field performance of tire treads, with NR exhibiting the best CC resistance followed by SBR and finally BR. The same trend was found with the rubber impact testing approach that allowed the CC behaviour to be quantified using a new physical parameter which is the CC propensity (P). The relative ranking for CC resistance for the three compounds followed the fatigue crack growth resistances of the materials but was exactly opposite to the ranking of DIN abrasion resistance. This provides evidence that CC damage from impact by mm-scale asperities and abrasion of rubber against μm-scale asperities exhibit distinct characteristics in rubber.

KEYWORDS:

• rubber
• tire
• chipping
• chunking
• testing
• equipment
• friction
• wear

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Radek Stoček http://orcid.org/0000-0003-2869-3892

Additional information

Funding

This article was written with the support of Operational Program Research and Development for Innovations co-funded by the European Regional Development Fund and national budget of the Czech Republic, within the framework of the project CPS – strengthening research capacity (reg. number: CZ.1.05/2.1.00/19.0409) as well supported by the Ministry of Education, Youth and Sports of the Czech Republic – Program NPU I (LO1504).