The Property of a Novel Elastic Material Based on Modified Waste Rubber Powder (MWRP) by the Establishment of New Crosslinking Network

Abstract

In this study, polycardanol, a long-chain acid, was synthesized and used as a reclaiming agent of waste rubber powder (WRP). Polycardanol can break S–S bond on the surface of WRP, and simultaneously WRP grafted by long chain (MWRP) is formed. The long chain on WRP has the potential to establish new crosslinking network, which can produce a novel elastic material based on WRP. The tensile strength of the elastic material from MWRP with thermal post-treatment can reach 4.6 MPa. Hexamethylenetetramine (HMTA) is helpful for the elastic material from MWRP to enhance the establishment of new crosslinking network, resulting in the tensile strength of 6.2 MPa. With the addition of 0.5 phr fiber and thermal post-treatment, the tensile strength of the elastic material based on MWRP is up to 8.4 MPa. In this study, polycardanol, a long-chain acid, was synthesized and used as a reclaiming agent of waste rubber powder (WRP). Polycardanol can break S–S bond on the surface of WRP, and simultaneously WRP grafted by long chain (MWRP) is formed. The long chain on WRP has the potential to establish new crosslinking network, which can produce a novel elastic material based on WRP. Strong adhesion between waste rubber powder (WRP) is often demanded in the cycling of waste rubber. In fact, strong adhesion can be achieved through the establishment of new crosslinking network by the grafted chains on the surface of WRP. Self-made long-chain acid can destroy S–S and C–S bonds of WRP to produce reactive points, and simultaneously long chain can be grafted on the surface of WRP. Scheme 1 is the structure scheme of the modified waste rubber powder by self-made long-chain acid (MWRP). The long chain on the surface of MWRP is characteristic with the structure of phenolic resin, which can be cured under heat and hardener (HMTA)again. The long chain on the surface of WRP endows WRP the potential to establish new crosslinking network, then a novel elastic material appears by the introduction of covalent adhesion between WRP.