Fabrication of a Protective Self- dissolution Polymer Film in Water

Hypothesis: Given the accumulation of large volumes of plastics used for packaging, such as polyethylene and polypropylene, which are not biodegradable in the environment, it is essential and very useful to use a type of plastic that is water-soluble and biocompatible. In this research, film samples with complete water solubility were made based on poly(vinyl alcohol) with a medium degree of hydrolysis, corn starch, glycerol as a plasticizer, talc as an anti-blocking agent with the role of reducing the adhesion of film layers, and calcium stearate as a thermal stabilizer additive
Methods: In the process of producing soluble films, the materials were processed into melts after physical preparation and mixing in a co-current twin-screw extruder. In the next step, the output of the extruder entered the blow film machine to produce film.
Findings: The results of water solubility and tensile tests, differential scanning calorimetry, thermogravimetry, and thermal mechanical dynamic analysis, and X-ray diffraction showed that increasing the amount of glycerol within the defined range decreased the time of solubility in water and increased elongation-at-break. A decrease in tensile strength, glass transition temperature, storage modulus, crystallinity, melting temperature and thermal degradation temperature were also observed. The range of tensile strength and elongation-at-break was 33.88 to 46.97 MPa and 114.25 to 187.26%, respectively. The produced films completely dissolved in water within a few minutes. The structure of the films was identified with a scanning electron microscope The size of the particles distributed in the film was less than 5 microns. In the film sewability test, first, the washing powder with dimensions of 1×3 cm inside the film was packed under a plastic thermal sewing machine. Under the conditions applied by the machine (rotation up to 500 rpm for 3 min), the film was free of opening or tearing.