# Effect of Block Polyether as an Interfacial Dispersant on the Properties of Nanosilica/Natural Rubber Composites

## TL;DR

This study uses block polyether to improve the dispersion of silica in natural rubber, enhancing the mechanical properties of the resulting composites.

## Contribution

A novel interfacial dispersant with a PEO-PPO-PEO structure is introduced to optimize silica dispersion in rubber composites.

## Key findings

- Block polyether with an HLB value of 13 showed the best silica dispersion and interfacial interactions.
- The composite with 1 phr of block polyether achieved a tensile strength of 28.9 MPa and 523% elongation at break.
- The HLB value significantly influenced the performance of the rubber composites.

## Abstract

To enhance the dispersion of silica within a natural rubber (NR) matrix and improve the modification efficiency of the silane coupling agent, a novel interfacial dispersant composed of block polyether with a PEO-PPO-PEO structure is employed in this study. This block polyether, consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), serves to reduce the surface energy of silica and improve its compatibility with the rubber matrix. Three types of block polyethers with different hydrophilic–lipophilic balance (HLB) values of 8, 13, and 22 are selected to regulate the surface tension of silica. Subsequently, bis[γ-(triethoxysilyl)propyl] tetrasulfide (TESPT) is used to further modify the silica surface, aiming to prepare high-performance rubber composites. The results indicate that the HLB value of the block polyether has a significant influence on the system. Compared with block polyethers having HLB values of 8 and 22, the block polyether with an HLB value of 13 demonstrated superior silica dispersion, leading to enhanced filler–rubber interfacial interactions. Consequently, both the mechanical properties and processability of the NR composites were substantially improved. When the dosage of this block polyether was 1 phr, the composite exhibited a tensile strength of 28.9 MPa and an elongation at break of 523%.