No abstract

A blend of natural rubber (NR) and styrene butadiene rubber (SBR) was tested against conventional rubber products sold in department stores and markets, using nuclear magnetic resonance (NMR) spectroscopy to measure the amount of natural or synthetic rubber in the product. 1H-NMR spectroscopy was employed for the rubber blend and 13C-NMR spectroscopy for conventional products. The chemical shift of all the samples from the structure of natural rubber (cis-1,4 polyisoprene) was observed.

The investigation focused on the properties of composite foam obtained by a compression molding method. The results could clarify the interaction among PLA, silica nanoparticles and coconut fiber. The compressive properties, including the compressive force and modulus of composites, contained in coconut fiber were improved. The incorporation of silica nanoparticles was able to modify the compressive properties slightly, whereas the thermal properties were decreased explicitly. Hydrogen bonding between the carboxylic group of PLA and the silica bonded group affected the increment in mechanical properties of composites. However, the incorporation of coconut fibers in composites exhibited a rougher surface. In addition, beneficial distribution of silica nanoparticles and porosity in the nanocomposite foam, equivalent to neat PLA foam, could be obtained.

This research attempted to prepare composite foams of PLA/bagasse fiber with various fiber content at 0, 5, 10, 15, 20 wt% and a fixed foaming agent with extra added 2 wt% for all composites. The mechanical properties and morphology of neat PLA and PLA/bagasse fiber composite foams were investigated. The tensile strength showed that the highest fiber content of 7 wt% was 45.27 MPa, while neat PLA was 25.63 MPa. Impact strength showed a decreasing trend with increasing fiber content. SEM analysis was important to reveal the phase of fiber and matrix for support to discuss the results trend of PLA and composite properties.

The effect of a blowing agents that affected Polylactic acid (PLA) and Epoxidized natural rubber (ENR) the blowing agents composed of citric acid (CA) and sodium hydrogen carbonate (NaHCO3) mixing by twin screw extruder with co-rotation screw. The properties of biodegradable foams were investigated. Blended foams of all composition were prepared by using compression molding at 200°C using different proportions of PLA, ENR, CA and NaHCO3. Mechanical properties of the samples were characterized by using universal testing machine. Thermal properties including Glass transition temperature (Tg), crystallization temperature (Tc) and melting temperature (Tm) were examined by using differential scanning calorimetry (DSC). Physical properties including morphology and density of blended foams were also investigated and morphological properties were studied with a scanning electron microscope (SEM).