Effects of molecular structure and molar content of acrylate units on aerobic biodegradability of acrylate copolymeric sizing agents

Abstract

This study was undertaken to establish a relationship between aerobic biodegradability and molecular structure of acrylate copolymers for the design and production of the copolymers with good biodegradability for warp sizing. Biological oxygen demand for five days (BOD₅) and chemical oxygen demand (COD) of the copolymers were assessed and the BOD₅/COD ratio was used to evaluate their biodegradability. The influence of the number of carbon atoms in the alkyl group of alkyl ester chain on the biodegradability was studied and the effect of α-methyl group was evaluated. Moreover, the impact of molar content of acrylate units on the biodegradability was also studied. It was found that the decrease in the number of carbon atoms in the alkyl group of alkyl ester chains and the reduction in molar content of acrylate units improved the biodegradability of acrylate copolymers. Biodegradation of acrylate copolymers proved to be difficult if an α-methyl group was present in the acrylate units. To produce acrylate copolymers that are able to biodegrade more easily, a suitable amount of acrylate monomers with shorter alkyl side-chains and without an α-methyl group should be applied to monomer formulation for the copolymerization with hydrophilic monomers. The preferred molar content of the acrylate monomers should be in a range of 60% to 70%. The acrylate copolymers thus prepared were biodegradable and aerobic biodegradation was capable of converting macromolecules to lower molecular weight end-products.