Examine the Physical Properties of Rubber-Modified Unsaturated Polyester for Potential Wearable Technology Applications

Abstract

This study examines the influence of incorporating natural rubber (NR) into unsaturated polyester resin (UP) on the thermal conductivity, friction coefficient, and wear rate. Three blend ratios (90/10, 60/40, and 50/50 UP/NR) were prepared to explore how varying NR content affects these properties. The results demonstrate that increasing the NR content leads to a significant rise in both the coefficient of friction and wear rate, particularly evident at the 50/50 composition. Specifically, the coefficient of friction increased by approximately 45–50%, while the wear rate nearly doubled compared with the 90/10 blend. Conversely, the thermal conductivity decreased progressively with higher NR ratios—by roughly 30% from the 90/10 to the 50/50 composition—due to the insulating nature of rubber. The 90/10 blend thus showed the highest heat transfer capability. Overall, the study confirms that blending UP with NR allows controlled tuning of material properties according to specific engineering needs. High NR content is advantageous for applications requiring impact absorption or vibration damping, whereas low NR content favors heat dissipation and wear resistance. In this context, UP reinforced with NR provides a balance of structural integrity and elasticity that can be valuable in wearable systems, including flexible housings, protective layers, vibration-damping elements, and thermal-insulating structures. Received: 25 November 2025 | Revised: 15 January 2026 | Accepted: 2 February 2026

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

Data are available from the corresponding author upon reasonable request.

Author Contribution Statement

Rafah Alwan Nassif: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization, Project administration. Raghad Hamid Hilal: Software, Validation, Investigation, Resources, Data curation, Supervision, Project administration.