Optimization of Cellulose Nanofibers and Castor Oil in the Synthesis of Starch-carrageenan-polyvinyl Alcohol Biothermoplastic Film

The improvement of the properties of starch, carrageenan, and polyvinyl alcohol (SCPVA) biothermoplastics film is necessary be used as packaging materials that comply with SNI 7818:2014 and international standards. The aim of this research is to optimize the concentration of cellulose nanofiber and castor oil in the synthesis of SCPVA bio-thermoplastic film; so that, the best characteristics are obtained and SNI 7818:2014 and international standards are met. Optimization was carried out using the Response Surface Methodology (RSM) application with the independent variable (input control variable) concentration of cellulose nanofiber and castor oil with the dependent variable (response variable) tensile strength, elongation at break, and Young Modulus. SCPVA bio-thermoplastic film with an optimal concentration of cellulose nanofiber and castor oil was observed for swelling, WVTR, surface profile, functional group content, thermal stability, and crystallinity by reviewing X-ray diffraction intensity. The research results showed that the optimum concentrations of cellulose nanofiber and castor oil in the synthesis of SCPVA biothermoplastic film are 6.05% and 0.96%, respectively. The tensile strength, elongation at break and Young's modulus values of the resulting optimum treatment are 37.21 MPa, 4.347% and 1041.86 MPa, respectively. Hence, with optimization, the SCPVA bio-thermoplastic film has the highest tensile strength and Young's modulus values but the lowest elongation at break values. The physical and mechanical characteristics of SCPVA bio-thermoplastic film have met SNI 7818:2014 and most of ASTM 5336, therefore, it can be used as packaging.