Deformation of microfibrillated chitin film and composites

Abstract

Composites of poly(acrylic acid) (PAA) and chitin whiskers were prepared using evaporation method. The weight fraction of chitin whiskers (CHW) was varied from 73 to 23%. Raman was utilised for the first time to monitor the deformation of chitin film and chitin-reinforced PAA composites. The Raman band located at 1622 cm−1 was monitored for deformation. On application of tensile force, the Raman band initially found at 1622 cm−1 corresponding to the single H-bonded amide one spectrum shifted towards a lower wavenumber. Raman band shift rates of − 1.85 cm−1/% for chitin film and − 0.25, − 0.59 and − 0.59 cm−1/% for 23, 43 and 73 wt% CHW whiskers, respectively, were obtained. The Young modulus of composites materials and whiskers were 37, 16 and 115 GPa, respectively, for a two-dimensional in-plane distribution of CHW. CHW within PAA did not show any preferential alignment. At high volume or weight of PAA or low weight CHW (3, 11% chitin) monitoring of the Raman peak shift was difficult.