Improved Flexural Strength, Modulus, KIC, and Compressive Strength of Epoxy Foam Modified with Natural Rubber

Mohamad Hussein; Teh Pei Leng; Abdul Razak Rahmat; Firuz  Zainuddin; Yeoh Keat

doi:10.26629/jtr.2025.69

Authors

Mohamad Hussein Ras Lanuf Oil and Gas Processing Company, PE Plant, Ras Lanuf, Libya Author
Teh Pei Leng Universiti Malaysia Perlis, Division of Materials Engineering, Faculty of Chemical Engineering Technology, 02600 Jejawi, Perlis, Malaysia Author
Abdul Razak Rahmat Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Bahru, Johor, Malaysia Author
Firuz Zainuddin Universiti Malaysia Perlis, Division of Materials Engineering, Faculty of Chemical Engineering Technology, 02600 Jejawi, Perlis, Malaysia Author
Yeoh Keat Universiti Malaysia Perlis, Division of Materials Engineering, Faculty of Chemical Engineering Technology, 02600 Jejawi, Perlis, Malaysia Author

DOI:

https://doi.org/10.26629/jtr.2025.69

Keywords:

epoxy foam, natural rubber, depolymerized natural rubber, foaming agent, mechanical properties.

Abstract

The study developed new epoxy composites enhanced with natural rubber (NR) and sodium bicarbonate (SB) as a foaming agent. Adding NR improved the epoxy’s toughness, flexural strength, modulus, and fracture toughness (K_IC), with optimal results at 10 vol% NR for flexural properties and 15 vol% NR for compressive strength. Increasing NR content led to greater expansion but reduced crosslinking and mechanical strength due to increased porosity. The improvement was attributed to small, uniformly dispersed NR phases that acted as energy dissipation centers, enhancing elasticity and load-bearing capacity. SEM analysis confirmed uniform dispersion of NR particles within the epoxy matrix, which significantly influenced mechanical performance.