Ethylene Propylene Diene Monomer-Based Composites Resistant to the Corrosive Action of Acetic Acid

TL;DR

This paper explores how EPDM-based composites with natural fillers resist acetic acid corrosion, offering eco-friendly material alternatives.

Contribution

The study introduces wood sawdust as a filler to enhance corrosion resistance in acidic environments while promoting sustainability.

Findings

Composites with 20 phr or 30 phr wood sawdust showed highest resistance to acetic acid corrosion.

Acetylation of hydroxyl groups reduced hydrophilicity and acid penetration in composites.

30% wood sawdust composites retained structural integrity with minimal cross-link density loss after 14 days.

Abstract

The potential of elastomeric composites reinforced with natural fillers to replace traditional synthetic materials in applications involving exposure to acidic environments offers both economic and environmental advantages. On the one hand, these materials contribute to cost reduction and the valorization of organic waste through the development of value-added products. On the other hand, the presence of wood waste in the composite structure enhances biodegradation potential, making these materials less polluting and more consistent with the principles of the circular economy. The present study aims to evaluate the behavior of composites based on Ethylene Propylene Diene Monomer (EPDM) synthetic rubber, reinforced with silica and wood sawdust, in a weakly acidic yet strongly corrosive environment—specifically, acetic acid solutions with concentrations ranging from 10% to 30%. The study also investigates the extent to which varying the proportions of the two fillers affects the resistance of these materials under such environmental conditions. Physico-chemical, structural, and morphological analyses revealed that the materials underwent chemical modifications, such as acetylation of hydroxyl groups. This process reduced the hydrophilic character of the sawdust and, combined with the formation of stable interfaces between the elastomeric matrix and the fillers during vulcanization, limited acid penetration into the composite structure. The composites in which 20 phr or 30 phr of wood sawdust were used-replacing equivalent amounts of silica from the initial 50 phr formulation-demonstrated the highest resistance to the corrosive environments. After 14 days of exposure to a 20% acetic acid solution, the composite containing 30% wood sawdust exhibited a decrease in cross-link density of only 1.44%, accompanied by a reduction in Young’s modulus of just 0.95%. At the same time, tensile strength and specific elongation increased by 22.57% and 26.02%, respectively. FTIR and SEM analysis confirmed good rubber-filler interactions and the stability of the composite structure under acidic conditions.

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