Effect of HAF carbon black on curing, mechanical, thermal and neutron shielding properties of natural rubber - Low-density polyethylene composites

Abstract

Abstract Flexible flame-retardant neutron attenuating composites were fabricated by adding a low volume percentage of low-density polyethylene (LDPE) along with high abrasive furnace (HAF) carbon black to natural rubber (NR) using the two-roll mill mixing method. The low volume percentage of LDPE was incorporated into NR to improve hydrogen atomic density. Further, the morphological, cure behavior, mechanical, dynamic mechanical analysis, thermogravimetric analysis, and neutron shielding studies have been performed to study the effect of HAF loading on NR/LDPE composites. HAF loading enhanced the vulcanization kinetics of the composites. Transmission electron microscopy images show that a uniform distribution of LDPE in NR matrix has been achieved by the HAF filler addition. Furthermore, the composites with 30\xa0phr HAF content with an average LDPE size of 0.27\xa0μm showed 15% and 34% increase in tensile and tear strength respectively. The dynamic mechanical analysis revealed that the storage modulus and polymer chain confinement of the composites have been increased with HAF filler addition. The thermal stability of the composites was improved to such an extent that they can be included in self-extinguishing material category with HAF filler loading. Total neutron macroscopic cross-section (~2\xa0MeV energy neutrons) of 0.2\xa0cm−1 was obtained for 30\xa0phr HAF filled composites. On the other hand, agglomeration of fillers occurs in the case of higher filler loading resulting in decreased properties of the composites.