Evaluation of biodegradability of green polyurethane/nanosilica composite synthesized from transesterified castor oil and palm oil based isocyanate

•Biodegradation of polyurethane and its nanosilica composite based on castor oil.•Biodegradation carried out under compost environment for 90 days.•FTIR, SEM, DSC, Weight loss curves utilized to analyse the rate of biodegradation.•Polyurethane/nanosilica composite exhibited higher rate of biodegradation.

This paper aims to assess the biodegradability of neat polyurethane and polyurethane/nanosilica composite based on transesterified castor oil and isocyanate derived from palm oil under composting condition for an exposure period of 90 days. Fungal and bacterial colonies have been isolated and identified from the surface of the degraded sample. The biodegradation of the films have been investigated in terms of change in structural, morphological, weight loss and thermal properties. The FTIR results indicated noticeable changes between the spectra of unexposed and exposed samples, with respect to decrease in the intensity of absorption bands corresponding to ester and urethane linkages suggesting the occurrence of biodegradation. The biodegradation has been also confirmed using SEM studies through the appearance of corrosive structures, cracks and surface pitting. However, faster rate of degradation has been observed in case of polyurethane/nanosilica composite owing to its surface hydrophobicity, lower crystallinity and presence of surface hydroxyl groups that facilitates attack of microorganisms.

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