Title
Evaluation of eco-friendly unsaturated polyester composites reinforced with agro-waste fillers
Authors
BASHAR AL-OGAIDI, SHAYMAA M. SALIH, MOHAMMED KADHOM and MOHAMMED A. FAYAD

Received August 14, 2025
Published Volume 59 Issue 9-10 October-December
Keywords polyester, walnut shell, date seeds, composite materials, mechanical properties, biowaste

Abstract
This research investigates the impact of incorporating agricultural waste materials, namely, date seed and walnut shell powder, into unsaturated polyester on its mechanical properties. Examination of the properties included tensile strength, flexural strength, impact resistance, and thermal conductivity. The date seeds and walnut shells were collected, crushed, and milled to produce powders with particle sizes of approximately 12.64 µm and 55.8 µm, respectively. The powders were mixed with unsaturated polyester at varying weight proportions (1%, 2%, and 3%); the samples were prepared by the hand lay-up method. The obtained results revealed that an increase in the content of powder enhanced the values of the characteristics studied. Specifically, the flexural strength of the composite with 2 wt% date seeds was 2.18 times higher compared to that of pure polyester. There was a variation in the tensile strength of the material with respect to the weight percentage of walnut shell powder, which was 1.5 times that of pure polyester. However, the hardness generally increased slightly and was likewise influenced by the percentage of filler, whereby the greatest improvement was achieved at 3% walnut shell loading . This study has shown that the reinforcement in composites can be sustainable, without requiring the use of expensive materials or complex processes.