MECHANICAL AND BARRIER PROPERTIES OF POLYLACTIC ACID/ SURFACTANT-STABILIZED GRAPHENE NANOCOMPOSITE FILM

Penambahan graphene sebagai nano-filler merupakan upaya untuk meningkatkan sifat mekanis dan water vapor permeability (WVP) dari Polylactic acid (PLA) sebagai biodegradable film. PLA dengan nanokomposit disiapkan melalui metode solution blending, menggunakan Tetrahydrofuran (THF) sebagai pelarut organik. Dalam upaya meningkatkan penyebaran graphene nano-platelets pada pelarut THF dan PLA, surfaktan quaternary ammonium, khususnya Didodecyldimethylammonium bromide (DDAB) dan Benzyl dimethyl dodecylammonium chloride (BDAC) yang digunakan untuk memodifikasi graphene dalam penelitian ini. Pengaruh rasio yang berbeda dari surfaktan dan graphene pada sifat mekanis dan WVP pada PLA/ surfactant-stabilized graphene nanokomposit film diteliti dan dilakukan perbandingan dengan film dari PLA/ graphene dan PLA control. Disimpulkan bahwa surfactant-stabilized graphene pada jumlah rasio surfaktan yang kecil dapat meningkatkan sifat mekanis (tensile strength dan elongation at break) dan menurunkan WVP, sedangkan pada rasio yang lebih tinggi, surfactant-stabilized graphene hanya menurun WVP dibandingkan dengan film PLA control. Penambahan Graphene dan BDAC-stabilized graphene meningkatkan nilai terbaik pada tensile strength 58% dan 21% serta elongation at break sekitar 38% dan 46%, pada masing-masing sampel, serta penurunan WVP sebesar 65% dan 52%, pada masing-masing sampel, dibandingkan dengan film PLA control. DDAB- stabilized graphene menurunkan kekuatan tarik sebesar 14%, elongation at break sebesar 23%, dan WVP 19% dibandingkan dengan film PLA control. Sebaliknya, rasio yang tinggi antara surfaktan/graphene dan stabilized graphene meningkatkan elongation at break pada PLA/ DDAB-stabilized graphene sebesar 12% dan menurunkan tensile strength sebesar 18-47%. Nilai WVP menurun sebesar 33-47% untuk kedua sampel film PLA/ BDAC- dan PLA/ DDAB-stabilized graphene, dibandingkan dengan film PLA control. Adding graphene as a nano-filler is an effort to improve the mechanical and water vapor barrier (WVP) properties of biodegradable Polylactic acid (PLA) films. The PLA nanocomposite films were prepared via solution blending method, using Tetrahydrofuran (THF) as an organic solvent. In order to improve the dispersion of graphene nano-platelets in THF and in PLA solution, the quaternary ammonium surfactants, specifically Didodecyldimethylammonium bromide (DDAB) and Benzyl dimethyl dodecylammonium chloride (BDAC) were used to modified graphene in this study. The effect of different ratio surfactant-stabilized graphene (0.1%wt) on the mechanical properties and the WVP of PLA/surfactant-stabilized graphene nanocomposites film was investigated compared with those of PLA/ Graphene and PLA neat film. It was found that graphene and low ratio surfactant-stabilized graphene could improve both mechanical properties (tensile strength and elongation at break) and decreased WVP, while high ratio surfactant-stabilized graphene decreased only WVP compared with PLA neat film. Graphene and BDAC-stabilized graphene on low ratio showed the best improvement that it increased the tensile strength 52% and 50% also elongation at break at about 38% and 43%, respectively, as well as decreased WVP at 57% and 51%, respectively, compared with PLA neat film. Addition DDAB-stabilized graphene would increse the tensile strength at 7%, elongation at break at 20%, and decrease the WVP 18% compared with PLA neat film. In contrast, high ratio of surfactant-stabilized graphene decreased both tensile strength and elongation at break, but increased .The water vapor barrier property at 17-18% for both PLA/ BDAC- and PLA/ DDAB-stabilized graphene films, compared with PLA neat film.