Effect of chitosan loading on structural and physical properties of polyvinylpyrrolidone/chitosan composites using simple casting process

This research focused on the development of polymer composite materials for dissolving needles applications. Polyvinylpyrrolidone (PVP) was selected as the matrix phase, with chitosan (CS) chosen as the reinforcement phase due to its unique ability to absorb various substances and maintain stability in a room-temperature environment. Acetic acid was used as a dissolving agent for the chitosan suspension. A 30% w/v PVP solution was prepared in deionized water under magnetic stirring. Subsequently, chitosan powder was dissolved in acetic acid (2 M) at a 1.00 : 1.75 mole ratio using an ultrasonic process. Different weight ratios of the chitosan suspension (0.0, 0.5, 1.0, 2.0, 5.0, and 10.0 wt%) were added to PVP matrix under continuous stirring at 200 rpm for 30 min. to achieve a homogenous suspension. Each PVP/CS suspension was then cast into a silicone mold and dried at 40 ºC in the oven. Examining the structural properties of the PVP/CS composite samples under an optical microscope revealed a well-dispersed arrangement of CS particles within the PVP matrix. In the chemical structure analysis using Fourier transform infrared (FTIR) spectroscopy, the spectra of the PVP composites with different CS ratios exhibited identical patterns for all the samples, indicating a correlation with the same phases in the precursor materials. Furthermore, the optimized ratio of 1 wt% chitosan loading in the PVP/CS composites achieved a balance between enhanced mechanical property and reduced solubility, influenced by the distribution of CS particles within the PVP structure. Moreover, the presence of hydrogen bonds between the NH2 groups in chitosan and the C=O groups in PVP plays a key role in mechanical enhancement and soluble time. GRAPHICAL ABSTRACT HIGHLIGHTS Polymer composites for soluble materials Polymer composite film by simple casting process Enhancing hardness property by PVP/CS polymer composites