Properties of cellulose‐polyester composites

Abstract Cellulose fibers were used as reinforcement in unsaturated polyesters. Composites were prepared as laminates with cellulose fibers used in the form of paper sheets. The impregnation was carried out in a vacuum and resulted in a composite with uniform distribution of polyester around the fibers. The polyester was also detected in the lumen of the fibers. The tensile properties were evaluated and compared with tensile properties of glass fiber reinforced polyester. It is found that cellulose fibers increase the tensile strength and modulus of a polyester composite. Immersion of the cellulose‐polyester composites in water caused a considerable water uptake. The presence of water in the composites decreased the tensile properties drastically. Scanning electron photomicrographs of the tensile fracture surfaces showed a lack of adhesion between the cellulose fibers and the polyester matrix in wet conditions.