Tarinee Nampitch

Preparation, Characterization and Properties of Ternary Blends with Epoxidized Natural Rubber, Poly (Lactic Acid) and Poly (Butylene Adipate-Co-Terephthalate)

The objective of this work was to study the production of new biodegradable thin films. As a result of increasing problems with regard to the disposal of domestic waste, particularly plastics, a new class of polymers especially designed to be biodegradable has been undergoing development. However these biodegradable plastics still have a limitation, i.e. high cost. This research studied methods of lowering the cost of biodegradable plastic and of improving its properties by using epoxidized natural rubber as a another polymer for polymer blends. Thus, ternary blends of epoxidized natural rubber (ENR), poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) were studied and prepared using a twin-screw extruder, followed by use of a chill roll cast film extruder or a blown film extruder, to produce biodegradable film. The concentration of ENR in the ternary blends was fixed at 10 wt%, with the remainder being PLA and PBAT. In some proportions of the film blends, Irganox and Uvinul were introduced to increase the thermal stabilization and UV stabilization, respectively. The mechanical and thermal properties were evaluated, including the thickness, color, and water vapor permeability (WVP) of the biodegradable films.

Mechanical and Morphological Properties of Poly(Lactic Acid)/Bagasse Fiber Composite Foams

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.

EFFECT OF COAGULATING SKIM NR PARTICLES AS NR–CLAY NANOCOMPOSITE: PROPERTIES AND STRUCTURE

Abstract New materials of skim NR–clay nanocomposites were prepared by a coagulating method using several organoclays, i.e., dodecyl ammonium–montmorillonite, Cloisite 15A, Cloisite 20A, and Cloisite 25A, which were modified by dodecyl ammonium chloride, dimethyl dehydrogenated tallow quaternary ammonium chloride, dimethyl dehydrogenated tallow quaternary ammonium chloride, and dimethyl hydrogenated tallow 2 ethylhexyl quaternary ammonium methyl sulfate, respectively. X-ray diffraction revealed that the intercalated nanocomposites were formed depending on the type and content of organoclays, and the excellent dispersion of clay in rubber matrix could be confirmed by transmission electron microscopy micrographs. In addition, thermal stability of the coagulated skim rubber–organoclay nanocomposites was improved as shown by the thermogravimetric analysis. The mechanical properties and dynamic-mechanical thermal analysis revealed that hardness and storage modulus of nanocomposites were improved and the glass ...

Mechanical Properties of Biodegradable Mulch Films Contained Poly(Lactic Acid) and Modified Natural Rubber Prepared by Blown Film Extrusion

The present research aimed to develop biodegradable mulch films that could resolve the environmental problem in agriculture. The research also compared the properties of transparent and black commercial mulch films. Blended films were prepared by blown-film extrusion, heating at 170 °C, and rotation at 55 rpm. The results revealed that the appearance of FTIR spectra were shown as functional groups of PBAT, described at 1710 cm-1 and 1267 cm-1, which corresponds to carbonyl groups in ester linkage and C-O in ester linkage, respectively. The presence of O-H carboxylic acids, attributed within the range 910-950 cm-1. The films containing 10% PLA loading showed peaks from 937 to 1712 cm-1, more than films containing 20% PLA loading. The carbon black contained in the biodegradable film could interrupt the mobility of the polymer chain, leading to decreased Tm, while the incorporation of carbon black in biodegradable mulch films could increase the tensile properties of blends.

Effect of the Citric Acid as Blowing Agent on the Compressive Properties and Morphology of PLA/ENR Blend Foams

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).

Investigation of Thermoplastic Starch/Fiber Blend: Effect of Tapioca Residue on the Mechanical Properties and Surface Study

The aim of this study was to characterize thermoplastic starch containing corn starch and tapioca residues, which were used as reinforcement in a blended matrix. In the process, the composites were prepared with different tapioca residue contents at 20, 30, 40, 50 and 60 % by weight using compression molding at 135 °C for 8 min. Subsequently, their mechanical, thermal and morphology properties were evaluated. The results showed that the reinforcing effect of tapioca residue lead an increase in the stiffness of the samples. Young’s modulus increased with higher tapioca residue content. When the loading of tapioca residue increased tensile strength for 80/20 and 70/30 mixtures from 7.46 to 8.58 MPa. In addition to the highest of tapioca residue could increase tensile strength dramatically. Further, the glass transition temperature tended to decrease with the increased loading of tapioca residue. Moreover, the morphology showed that the increment of tapioca residue content appeared embedded in the polymer matrix.

Properties of HDPE/Biodegradable Polymer Blends Using Modified Rubber

Biodegradable blends consisting of poly(lactic acid) (PLA), poly(butylene adipate-coterephthalate) (PBAT) and epoxidized natural rubber (ENR) were blended in two proportions at PLA/PBAT/ENR ratios of 70/10/20 and 70/20/10. Then, blends these biodegradable polymers (PLA/PBAT/ENR) with HDPE at various ratios of 20/80, 10/90 and 5/95 wt%, the mechanical and morphological properties were investigated. Tensile tests of PLA/PBAT/ENR blends revealed high tensile strength and modulus but low elongation compared with HDPE. The tensile strength, elongation at break and impact strength of HDPE/biodegradable polymer blends decreased with increasing biodegradable polymer contents. Morphological properties of HDPE/biodegradable polymer blends were investigated by scanning electron microscope, which showed smoother surface of HDPE/biodegradable (70/10/20) than those of (70/20/10) polymer blends according to ENR compatibilization effect.

Compressive Properties of Polylactic Acid-Based Nanocomposite Foams Reinforced with Coconut Fibers

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.

The Effects of Bagasse Fiber Loading on the Mechanical Properties of Skim NR–Clay Nanocomposites

Skim natural rubber (NR)–clay nanocomposites were prepared by a coagulation method using the organoclays Cloisite 15A, Cloisite 20A and Cloisite 30B. This work investigated the use of bagasse fiber developed from locally sourced and renewable material as an alternative and/or secondary filler in skim NR–clay nanocomposites. Bagasse fiber loading in the nanocomposites was 0, 5, 10 and 20 phr; the effects of fiber content on cure characteristics and mechanical properties were then determined. The results suggest that the Mooney viscosity tended to increase with increasing fiber content, whereas the cure time at 90% and fatigue testing score decreased as fiber loading increased.

Mechanical and Thermal Properties of Toughened PLA Composite Foams with Modified Coconut Fiber

Composite foams from PLA, natural rubber and modified coconut fibers was prepared employing a compression molding method, which is suitable for the fabrication of composites containing high fiber content. The results revealed that the incorporation of natural rubber into composite foams increases the compressive stress to 101.17 kN/m2. Further, a 10% wt increase of modified coconut fiber added into composite foams resulted in an increase of compressive stress to 105.24 kN/m2. The addition of modified coconut fibers in composite foams showed a slight decrease of the crystallization state, obtained by DSC results by about 1-3 oC. Thus, modified coconut fibers played a role as a nucleating agent. Moreover, the combination of modified coconut fibers in composite foams could lead to improved adhesion between the surface area of PLA matrix and the natural rubber phase.