Preparation and recycling property of nanofiber-reinforced polystyrene molded product using the emulsion-forming ability of chitin nanofibers

Utilizing the emulsion-forming ability of partially deacetylated chitin nanofibers, a composite with polystyrene was prepared. A partially deacetylated chitin nanofiber aqueous dispersion was added to styrene to obtain an oil in a water-type Pickering emulsion. Using the emulsion, suspension polymerization was performed to obtain polystyrene fine particles covered with chitin nanofibers. The degree of polymerization of polystyrene increased depending on the mixing ratio of chitin nanofibers. The glass transition temperature of polystyrene and the thermal decomposition temperature of the composite increased with the mixing ratio of chitin nanofibers. This composite could be molded by hot pressing, and the molded product was transparent to some extent. Since chitin nanofibers effectively reinforced polystyrene, Young's modulus, fracture stress, and fracture strain were greatly improved. The optimum mixing ratio of chitin nanofibers for improving mechanical properties was 7%. When the composite was molded by hot pressing again, the mechanical properties did not decrease. Thus, the nanofiber reinforcement material was recyclable. Utilizing the emulsion-forming ability of partially deacetylated chitin nanofibers, a composite with polystyrene (PS) was prepared. A partially deacetylated chitin nanofiber aqueous dispersion was added to styrene to obtain an oil in a water-type Pickering emulsion. Using the emulsion, suspension polymerization was performed to obtain PS fine particles covered with chitin nanofibers. This composite could be molded by hot pressing, and the molded product was transparent to some extent. Mechanical properties of PS were greatly improved. When the composite was molded again, the mechanical properties did not decrease.

Automated summary

Utilizing the emulsion-forming ability of partially deacetylated chitin nanofibers, a composite with polystyrene was prepared, significantly improving the mechanical and thermal properties of polystyrene. The optimal mixing ratio of chitin nanofibers for improving mechanical properties was 7%. The composite material showed good recyclability without a decrease in mechanical properties after hot pressing molding.