Film properties from crosslinking of cellulosic derivatives with a polyfunctional carboxylic acid

In order to decrease water sensitivity of packaging materials based on water-soluble cellulose derivatives, and especially to avoid partial solubilisation of films into food products, crosslinking of hydroxy propyl methyl cellulose (HPMC) with citric acid was carried out using different contents of polycarboxylic acid and catalyst. To determine reticulation rate or ester bond rate in crosslinked cellulosic derivatives, FTIR in transmittance, based on of the ester band (1735 cm−1) was compared to acid–base titration. Infra-red spectroscopy had advantages over time consuming titration. Crosslinking of the hydrophilic polymers induced a strong influence on water solubility and an improvement in the water vapor barrier of about 34%.