Self‐reinforced natural rubber composites: Preparation and properties study

Abstract

In the contemporary modern mining sector, rubber conveyor belts are extensively and frequently utilized. Exceptional tear resistance and high elongation of the top cover rubber of the belt are imperative. In this investigation, a portion of natural rubber (NR) underwent partial vulcanization in advance. Subsequently, this pre‐vulcanized NR (PNR) was mixed with the NR matrix via mechanical blending. Due to the increased viscosity resulting from pre‐vulcanization, the PNR may disperse in the NR matrix, maintaining a specific microstructure without complete dissolution. During subsequent vulcanization, the PNR could co‐vulcanize with the NR matrix, forming a well‐bonded interface and ultimately yielding self‐reinforced NR (SNR) composites. The influences of the mass ratio of PNR to the NR matrix, sulfur content in PNR and pre‐vulcanization time on the mechanical properties of the SNR composites were thoroughly investigated. The results indicated that adding PNR effectively improved the tear strength of NR. When the PNR replaced 20 wt% of NR, sulfur content in PNR was 2.4 phr and pre‐vulcanization time was 2 min, the tear strength, stress at 300% elongation and wear resistance of SNR composites increased by 34.1%, 16.6%, and 10.2% compared to NR control sample, while elongation at break remained at 898%. These findings suggest that it is possible to enhance the tear strength of rubber without compromising elongation at break.