Mechanistic aspects of silane coupling agents with different functionalities on reinforcement of silica‐filled natural rubber compounds

Abstract

Silane coupling agents containing different specific functionalities are studied to gain understanding of their roles in silica‐filled natural rubber (NR) compounds. Five different silane coupling agents, that is bis‐(triethoxysilylpropyl) tetrasulfide (TESPT), bis‐(triethoxysilylpropyl) disulfide (TESPD), octyltriethoxysilane, vinyltrimethoxysilane, and bis‐(trimethyl‐silylmethyl) tetrasulfide (TMSMT), are comparatively investigated, by taking the most commonly used TESPT as a reference. The results reveal that alkoxy‐based silanes can effectively reduce the filler–filler interaction and lower compound viscosity owing to the effect of silane‐to‐silica hydrophobation which contributes to better compatibility between silica and NR. The alkoxy‐silanes with a sulfur moiety, that is TESPT and TESPD, show more pronounced improvement in overall properties as a result of filler–rubber interactions. The use of TMSMT which has no alkoxy groups but contains only a sulfur moiety elucidates that there are three reaction mechanisms involved in systems with sulfur‐alkoxy‐based silane. These are as follows: (1) the silane‐to‐silica or silanization/hydrophobation reaction; (2) the silane‐to‐rubber or coupling reaction; and (3) rubber–rubber crosslinking originating from active sulfur released by the polysulfide‐based silane TESPT. These simultaneous reactions are temperature dependent, and show an optimum level at a dump temperature of approximately 140–150°C, as depicted by filler–filler and filler–rubber interactions, as well as mechanical properties of such compounds. POLYM. ENG. SCI., 55:836–842, 2015. © 2014 Society of Plastics Engineers

Biologically sustainable rubber resin and rubber‐filler promoter: a precursor study

“…The significant reinforcement of HDS formation is caused by BR‐FNR coupled with ENR. Hence, the BR‐FNR, being multi‐functional ample aromatic hydroxyl groups, provides sites for hydrogen bonding to promote greater silica dispersion into the green composite . This observation ascribed to the dispersion of HDS is largely improved, and the effective filler network consistently decreases.…”

“…Natural rubbers are extensively used in elastomer products and tire applications. Natural rubbers, together with ENR 25, are vulnerable to provide the balanced tire tread properties such as low abrasion loss, high wet grip and low rolling resistance . In general, NR‐HDS filled compound still remains a challenge resulting in greatly deteriorated tire properties in the absence of silane coupling agent and process oil .…”

Silane Coupling Agents

“…These include use in rubbers (41,42), as in tires, metals (11), and metal oxides, advanced composites (43), and naturally occurring fibers (44). Treated silica containing glassy polymers are particularly important in materials such as dental restoratives (45).…”

A Study on the Rheological and Mechanical Properties of Photo-Curable Ceramic/Polymer Composites with Different Silane Coupling Agents for SLA 3D Printing Technology

“…is an organic functional group that enhances the interaction with polymers through the formation of interpenetrating networks (IPNs). Different organofunctional groups in the silane coupling agents create different interfaces and different IPN phenomena between the polymer and ceramic particles, and the ceramic/polymer composites exhibit different rheological behavior and different mechanical properties [13,14,15]. However, in the field of ceramic 3D printing with the SLA method, research on the characteristics of 3D-printed objects by the affinity control of the interface between the polymer and ceramic particles is lacking.…”