Synthesis and characterization of Dioscorea hispida sp. tuber starch-polyacrylamide wood coating and its facile inhibitory towards Pycnoporus sanguineus and Coptotermes curvignathus

• Dioscorea Hispida starch based coating-gel is a new coating material that has not been investigated by any researchers.
• It has very good resistancy towards fungus and termite due to the alkaloid (dioscorine) content of the yam.
• FTIR and DSC results showed convincing physical and thermal behavior of the starch coating.
• The smooth topography images by Optical Microscopya and SEM showed a homogeneous dispersion of starch at different ratios of starch-polyacrylamide coating gel.

A unique, non-leaching and durable novel anti-biocide polyacrylamide-starch coating (pAam-g-S) has successfully been synthesized. In this study, a grafted cationic-functionalized polymeric coating was designed and cross-linked with native starch extracted from Dioscorea hispida sp. yam to afford multifunctional anti-fungal and anti-termite coating. Leaching of the disinfectant into the environment was eliminated because no toxic chemicals were used. The copolymerization was successfully carried out to produce various ratios of pAam-g-S coating using modification of starch-gel. Results obtained from Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) confirmed the monomer pAam was grafted onto the starch backbone as shown by the cross-linked peak at 1642 cm−1. Supported by differential scanning calorimetry (DSC), the highest transition glass temperature was observed at 154 °C. The coating was designed to continuously decontaminate against pathogenic fungus and termite in addition to afford preliminary anti-biocides properties. Facile anti-fungal and anti-termite evaluations were conducted via total weight loss of wood (%) studies using white rot fungus, Pycnoporus. sanguineus and termite Coptotermes curvignathus respectively. In order to verify the coating performance, gel fractions, morphologies and heat resistant properties were also investigated.