Thermal properties, i.e. melting point and decomposition temperature of polymers, azodicarbonamide (ADC), and other additives mixture, are the most important information to determine the appropriate foaming process parameters. ADC has been widely used as a blowing agent for foam fabrication. Here, ADC will decompose and release gas which will be trapped in the melting polymer to make a foamed product. Originally, ADC has a decomposition temperature at around 220°C. In this study, the effect of Zinc Oxide (ZnO) addition on the thermal properties of intermediate product and Polyethylene/Ethylene Vinyl Acetate (PE/EVA) foam with ADC as the blowing agent was investigated. ZnO addition decreased the decomposition temperature of ADC. The thermal properties were characterized by Differential Scanning Calorimetry (DSC). The result showed that the decomposition temperature of ADC significantly decreased from the temperature of 220°C to 170°C with the increment of the ZnO.

AbstrakPencampuran polimer (polymer blending) merupakan salah satu metode yang telah dikembangkan untuk merekayasa material polimer. Dalam penelitian ini telah dilakukan pembuatan komposit mikrofibril PET-HDPE dengan menggunakan alat ekstruder tipe co-rotating twin screw. Proses pembuatan komposit dalam alat ekstruder dengan parameter temperatur 170°C; 240°C; 265°C dan 280°C pada kecepatan putaran 40 rpm. Kondisi temperatur penarikan (drawing) pembuatan komposit diatur pada variasi temperatur 75°C; 80°C dan 85°C serta kecepatan rasio penarikan 2;3;4 dan 5 kali lebih cepat dari kecepatan awal. Hasil pembuatan komposit mikrofibril PET-HDPE dilakukan analisis sifat mikro dengan alat SEM (Scanning Electron Microscope) dan sifat mekanik dengan alat UTM (Universal Testing Machine) dan impact charpy. Pada penelitian ini didapatkan nilai kuat tarik tertinggi 24,60 MPa pada kondisi temperatur 85°C dengan kecepatan rasio penarikan 2 kali. Kekuatan impak tertinggi komposit PET/HDPE adalah 131.49 MPa pada kondisi temperatur penarikan 85 o C dan rasio kecepatan penarikan 4 kali. Sedang hasil analisa mikro menggunakan SEM terhadap komposit mikrofibril PET-HDPE belum dihasilkan fiber PET yang diharapkan pada komposit. Hal ini kemungkinan disebabkan proses penarikan yang tidak stabil dan temperatur penarikan yang belum tercapai. Kata-kata kunci: Komposit mikrofibril, ekxtruder twin screw, pencampuran polimer PET-HDPE AbstractPolymer blending is one of the methods that have developed to create new polymer materials with different physical properties. This paper aims to investigate of tensile strength, impact strength of microfibril PET-HDPE composites and to obtain PET fiber. Composites were prepared in co-rotating twin screw kneader extruder type ZK 25 E x 36 L/D. The tensile strength, impact Charpy strength from microfibril PET-HDPE and microstructure PET fiber was characterized using Shimadzu AG-X plus 50kN Universal Testing Machine, Resil Impactor CEAST and JEOL JSM 6510 LA Scanning Electron Microscope. Composites were varied at temperature 170 o C, 240 o C, 265 o C and 280 o C and mixing speed was controlled at 40 rpm. Drawing temperature was set at 75 o C, 80 o C, 85 o C, ratio drawing speed at 2; 3; 4 and 5-time initial drawing speed. The results showed that maximum tensile strength is 24.60 MPa on condition 85 o C with ratio drawing speed 2-time initial drawing speed. The maximum impact Charpy strength is 131.49 MPa on condition 80 o C with ratio drawing speed 4-time initial drawing speed. The result of microstructure was not obtained PET fiber. In this case, caused by drawing speed was not stable drawing temperature was not reached.