pH-Sensitive Biodegradability of Poly(Maleic acid-co-Malic acid-coButane-1,4-diol-co-Adipic acid) for Smart Release of Fertilizers

Poly(Maleic acid-co-Malic acid-co-Butane-1,4-diol-co-Adipic acid) was synthesized in xylene medium using Dean-Stark apparatus. Corresponding monomers were taken in stoichiometric ratios. A trace amount of anhydrous ferric chloride was added as catalyst. The reaction temperature and time were 135-140°C and 5 hours respectively. The synthesized co-polyester was characterized by its solubility test in common organic solvents, molecular weight, FTIR-spectrum, TGA, hydrolytic test and soil burial biodegradability tests. The end group analysis and viscosity methods were used for molecular weight determination. From the hydrolytic degradation study it was found that the polyester sample remained almost intact in the acid medium but gradually degraded in the basic medium. Soil burial test reveals that the co-polyester is almost mixed with the soil within two months which indicates its biodegradability in the soil. Because of these special characteristics this co-polyester could be a future endeavor for smart release of fertilizers.