Monomers of bis-(2-hydroxyethyl) fumarate and bis-(6-hydroxyhexyl) fumarate were synthesized from ethylene glycol and 1,6-hexanediol, respectively, with fumaric acid in the presence of p-toluene sulfonic acid as catalyst. The new unsaturated polyester resins were made through
condensation reaction between the monomers and terephthaloyl chloride. The chemical structures of these monomers and polymers were confirmed by CHN analyses, FT-IR, 1H-NMR and extended by thermogravimetric analysis (TGA) as well as differential scanning calorimetry (DSC). New oil
palm empty fruit bunches (OPEFB) reinforced polyester composites were then derived from the new unsaturated polyester resins containing bis-(2-hydroxyethyl) fumarate and bis-(6-hydroxyhexyl) fumarate. The mechanical properties (tensile, flexural and impact) and water absorption of the new
oil palm empty fruit bunches reinforced polyester composites were studied and compared with fiberglass reinforced polyester composites.