Graft Copolymer of Cellulose and Saturated Polyester as a Compatibilizer in an Epoxy Composite

Cellulose is a biopolymer of great interest for biomedical applications, providing increased rigidity and strength in polymer matrices, biocompatibility, and non–toxicity. However, the hydrophilic structure of cellulose leads to the aggregation of its particles in hydrophobic matrices. The presence of OH groups in the cellulose structure opens up wide possibilities for its chemical modification in order to improve compatibility. Most cellulose modification processes involve expensive toxic solvents, which helps to reduce the environmental friendliness of the process.

Graft copolymerization of cellulose and polyester resin based on sebacic acid was carried out by the method of mechanochemical activation, and a compatibilizer was obtained. The IR spectroscopy method shows the grafting of polyester to cellulose and selects the optimal amount of polyester for the complete interaction of the hydroxyl groups of cellulose. Epoxysmole was chosen as the matrix. Composites with different contents of graft copolymers of cellulose and polyester were obtained. The surface structure of the composites was analyzed using scanning electron microscopy. The uniformity of the filler distribution in the matrix and the uniformity of the structure were shown regardless of the amount of filler. The main physical, mechanical, and operational characteristics of the composites weredetermined. In comparison with the unfilled composite, the samples demonstrated an 8% increase in the strength of composites at a content of 0.5% and a 20% increase at a content of 1%; a significant increase was also observed in the modulus of elasticity (200% and 270%, respectively), and the deformation index increased with a low filler content, followed by a slight decrease. Thermal analysis of the composites did not show a noticeable decrease in the thermal stability of the samples.

Bisompatible and biodegradable graft copolymers of cellulose and polyester resin were obtained with the possibility of use in various polymer matrices for medical purposes.