Biodegradable-stimuli sensitive xanthan gum based hydrogel: Evaluation of antibacterial activity and controlled agro-chemical release

Abstract

Biodegradable hydrogel based on xanthan gum graft co-polymerized with polyacrylic acid was fabricated by free radical polymerization in presence of microwave radiations and its potential utility as bactericidal agent along with controlled agro-chemical release device was explored. The biodegradability was tested using soil burial method and it has been observed that the synthesized semi-interpenetrating (semi-IPN) was degraded upto 78.3% by weight with 1.11% rate of degradation per day within 70days. FT-IR and SEM micrographs further confirmed the biodegradable nature of the test sample. The Phaseolus vulgaris plants were grown in the soil containing the degraded sample and depicted healthy growth characteristic indicated the absence of any harmful end products from degraded sample. The semi-IPN was also found to bactericidal in nature against bacterial strains such as Bacillus subtilis and Salmonella enteritis probably due to ion-exchange effect. Also, the synthesized sample was used for the controlled release of urea and its release dynamics were studied. The macromolecular relaxation of the matrix was found to be comparable to diffusion rate of urea indicated by the non-Fickian (n=0.76) diffusion mechanism. Initial diffusion coefficient (Di=3.50×10−5m2h−1) was found to be greater than late diffusion coefficient (DL=2.31×10−6m2h−1) and indicated the prolonged release of urea. So, synthesized semi-IPN could be labeled as biodegradable, non-toxic, stimuli sensitive, antibacterial along with controlled release device for agro-chemicals.