Avocado seed starch and carboxymethyl cellulose superabsorbent polymer: Synthesis and characterisation.

Abstract

Superabsorbent polymers (SAPs) of crosslinked avocado seed starch and carboxymethyl cellulose were synthesized and their performance as fluid absorption materials was assessed by comparing them with those made from analytical grade starch. The SAPs were characterized by water absorption capacity (WAC) tests, Fourier transform infrared spectroscopy analyses, solubility fraction tests, effects of crosslinker quantity and swelling rate were investigated to determine the suitability of avocado starch in the synthesis of SAPs. Avocado seed starch was used in the superabsorbent polymer framework because of its biodegradability, abundance and limited use as a source of food for human consumption. The results of the research showed that the SAPs produced with avocado seed starch and those made from pure starch have comparable properties. The WAC for the avocado seed starch blend was 39g/g (3900% of the original weight) when the ratio of the avocado starch, carboxymethyl cellulose and aluminium sulphate was 88: 9.7: 2.3 respectively. The pure starch blend with a similar weight ratio had a WAC of 46.5g/g. As the amount of either starch was increased the differences between the WAC of the SAPs were less than 3.0g/g. FTIR spectra of the SAPs showed no significant differences between avocado starch and pure starch SAPs. The soluble fraction results showed that avocado SAPs had good gel formation. Analysis of experimental data by GraphPad Prism 6.0, one way Anova showed that there was no significant difference between the two types of SAPs for all the tests conducted. Avocado seed starch can therefore be used in the synthesis of superabsorbent polymers. It can be used as a substitute for starch extracted from agricultural plants that have already been studied in detail.