Effects of Hydroxypropyl Methylcellulose on Physicochemical Properties and Microstructure of κ-Carrageenan Film

We investigated the effects of different proportions of hydroxypropyl methylcellulose (HPMC) on the properties of kappa-carrageenan film. Biodegradable kappa-carrageenan/HPMC films (kappa CHM film) were prepared by the solution casting method and their physicochemical properties were evaluated. The results show that the addition of HPMC enhanced oxygen barrier capacity, mechanical properties (tensile strength and elongation at break) and thermal stability. Notably, when the addition of HPMC increased to 6% of kappa-carrageenan (w:w), the kappa CHM-6 film not only effectively improved water resistance, including lower water solubility, water vapor permeability and higher water contact angle, but also made the structure of the kappa CHM-6 film more compact. Moreover, rheological measurement and atomic force microscopy characterization showed that kappa-carrageenan had suitable compatibility with HPMC. Attenuated total reflection-Fourier transform infrared spectroscopy analysis further confirmed the enhancement of hydrogen bond interactions. This finding could contribute to promoting the potential application of kappa CHM film in food packaging.