Supaphorn Thumsorn

Effects of Compatibilizers on Properties of Polypropylene/Bamboo Fiber Composites

Bamboo fiber (BF) reinforced thermoplastic material composites were prepared in this study. polypropylene (PP) was compounded with bamboo fiber in a twin screw extruder at bamboo fiber contents of 0-30 wt% with polyethylene grafted maleic anhydride (PE-g-MA) as modifying agent. PP/bamboo fiber composites were to dumbbell specimens by injection molding process. The effect of bamboo fiber contents on properties of the composites was investigated. Tensile and storage modulus of the composites increased when increasing bamboo fiber contents. It can be noted that bamboo fiber promoted crystallization and enhanced crystallinity of PP in the composites, which improved the composites mechanical performance. On the contrary, tensile strength of the PP/BF composites was almost unchanged. Nevertheless, it was considering that the level of interaction between bamboo fiber and PP could be enhanced at higher contents of PE-g-MA. It can be noted that fracture toughness of the PP/BF composites was maintained at the BF contents of 10 wt%, which was attributed to the good interaction between bamboo fiber and PP matrix with the addition of PE-g-MA.

Optimizing of vented injection molding on mechanical performance and miscibility of recycled poly(ethylene terephthalate) and polycarbonate blends

Abstract Blending of recycled poly(ethylene terephthalate) (RPET) and polycarbonate (PC) was performed by melt compounding. The blends were subsequently fabricated to dumbbell specimens by vented injection molding. The mechanical properties, thermal characteristic and morphology of RPET/PC blends were investigated as a function of PC contents. Vented injection molding presented an advantage for superior mechanical properties of RPET/PC blends. The addition of PC enhanced impact strength and fracture toughness with remaining tensile properties. The glass transition temperatures of PET and PC shifted toward each other, which indicated their partial miscibility of RPET and PC in the blends. The toughness mechanism of RPET and PC was related to core-shell structure and good interfacial adhesion at higher contents of PC.

Crystallization kinetics and thermal resistance of bamboo fiber reinforced biodegradable polymer composites

Bamboo fiber reinforced biodegradable polymer composites were prepared in this study. Biodegradable poly(butylene succinate) (PBS) was blended with bamboo fiber in a twin screw extruder with varied bamboo content from 20-0wt%. PBS/bamboo fiber composites were fabricated by compression molding process. The effect of bamboo fiber contents on properties of the composites was investigated. Non-isothermal crystallization kinetic study of the composites was investigated based on Avrami equation. The kinetic parameters indicated that bamboo fiber acted as heterogeneous nucleation and enhanced crystallinity of the composites. Bamboo fiber was well dispersed on PBS matrix and good adhered with the matrix. Tensile strength of the composites slightly deceased with adding bamboo fiber. However, tensile modulus and impact strength of the composites increased when increasing bamboo fiber contents. It can be noted that bamboo fiber promoted crystallization and crystallinity of PBS in the composites. Therefore, the compo...

Development of Cotton Candy Method for High Productivity Polypropylene Fibers Webs

The cotton candy method (CoCAM) is developed for high productivity of polymer micro-and nano-fibers. Polypropylene was molten in a single screw extruder of the CoCAM at air pressures of 0.2-0.5 MPa with nozzle temperatures of 280-350 °C and the constant air temperature of 600 °C. The distance from the nozzle to the collector was set at 10-90 cm. Thermal images informed the accumulation of PP fibers flows at shorter collector distance. The diameters of PP micro-fibers decreased with increasing the air pressures and the nozzle temperatures. Crystallinity of the PP micro-fibers increased when increasing the nozzle temperature due to higher occasion of molecular orientation. The degree of the fiber entanglement in the PP micro-fibers decreased when increasing the collector distance, which affected on the declination of tensile strength. Ductility of the PP micro-fibers improved at high collector distances. The optimum condition of the PP micro-fibers was found at the average diameter of 2.3 μm at 0.5 MPa with the nozzle temperature of 340 oC collected at 60 cm. The productivity of the PP micro-fibers webs from the CoCAM was 144 g/h.

RETRACTED: Fabrication of Poly(Lactic Acid) Nanofibers by Cotton Candy Method

The poly (lactic acid) (PLA) fiber of biodegradable polymer was fabricated by cotton candy method with small nozzle. The air pressure was varied from 0.2-0.5 MPa with nozzle temperature of 210-260°C. The morphology of fiber was determined by scanning electron microscope (SEM). Thermal properties were examined using differential scanning calorimetry (DSC). SEM results suggested that diameters the PLA fiber at temperature 250°C and air pressure of 0.2 MPa were smaller than the fiber at low and high temperature. The sizes of the fibers were lower than 1 μm and the fibers were irregular size. Crystallinity significantly decreased when increasing barrel temperatures while it slightly changed when varied air pressure. The productivity of PLA fibers was around 30-180 g/h depended on controlled the nozzle temperature and the air pressure.

Investigation on Fracture Behavior of Glass Fiber Reinforced Thermoplstic and Thermosetting Composites

Glass fiber reinforced thermoplastics and thermosetting composites were prepared in this study. Commercial grades of 20% glass fiber filled polypropylene, polyoxymethylene, polyamide 6 and polycarbonate were injection molded to dumbbell specimens. The specimens are referred as GF/PP, GF/POM, GF/PA and GF/PC, respectively. 55% GF reinforced novolak composites were fabricated by hand lay-up, which different curing times of 20 s, 35 s and 50 s. Mechanical properties, fracture behavior and morpgology of GF composites with and without notched were investigated. GF/PA showed the highest properties of tensile properties, notched strength and fracture toughness as compared to all of GF reinforced thermoplastics in this research. On the other hand, tensile properties and fracture toughness of GF reinforced novolak increased with increasing curing times. SEM photographs indicated ductile fractured surface near the crack edge while their brittle appeared at far of the crack in GF reinforced thermoplastics. It can be noted that notched sensitivity of GF reinforced thermoplastics was lower than GF reinforced thermosetting composites.

Investigation of Friction and Wear Behavior of Polyoxymethylene/Poly(Lactic Acid) Blends

Friction and wear behavior of Polyoxymethylene/Poly (lactic acid) blends (POM/PLA) was investigated to study effect of PLA content on friction and wear properties. The sliding experiments were carried out by Frictoron EFM-III machine. POM blends sliding against the carbon steel (AISI 1045) counterpart under 200 N of pressure load, 100 mm/s of sliding speed for 60 minutes. The wear weigh loss was measured after wear experiment. Wear profile and worn surface were observed by SEM. It was found that friction coefficient of neat POM is lower than neat PLA. However, the incorporation of PLA into POM led to an increment of friction coefficient of POM blends both of 40% and 60% PLA content that over than neat POM and PLA. While wear weigh loss resulted the increasing with increasing of PLA content, which were supported by wear prolife photographs. The deformation of neat PLA and blends on worn surface originated from adhesive due to the thermal softening and melting behavior, while neat POM reveals the plough action behavior.

Interfacial Characteristics of Insert-Injection Molding by Using Acoustic Emission

Aim of this study focused on insert injection molding process, which is molded the melted polymer around an inserted part placed in the molded cavity of injection molding process. The interfacial adhesive strength between the inserted and an injected polymer parts were investigated by Intron universal test machine in order to investigate the effect of material in inserted and injected part. During tensile testing the acoustic emissions (AE) measurement was applied to evaluate the fracture behavior of insert injection molding. It was found that interfacial adhesive strength of insert injection molded of all specimens increased according with increasing the bonding area of adhesive interface. The fracture mode of the insert injection molded specimens was depended on the length of bonding area of the inserted part. The fracture of mode of the insert-injection molded specimens was confirmed by acoustic emission.

Crystallization, mechanical properties and thermal stability of cockleshell-derived CaCO3 filled polypropylene

This study discusses the potential of utilizing waste cockleshell derived-CaCO3 (CS) as filler in polypropylene (PP). Mineral fillers were prepared from cockleshell-derived CaCO3 and used to fill polypropylene. The composites were prepared by melt blending and fabricated by injection and compression molding techniques. The effects of filler on crystal structure, crystallization and thermal degradation characteristics of filled polypropylene composites were elucidated. The cockleshell filler promoted the formation of the β-crystalline phase in PP, which improved the rigidity and toughness of the composites. However, stearic acid treatments on the filler would significantly affect the nucleation process and therefore hindered crystallization. Acceleration in thermal degradation of PP was also noted with increasing filler loading.

Mechanical and Physical Properties of Roof Tile Prepared from Sugar Cane Fiber

Sugar cane, renewable fiber resources, were used for roof tile production. Urea formaldehyde, phenol formaldehyde and isocyanate resin were used as binders in this study. Roof tile specimens with 400 mm wide, 400 mm long and 5 mm thick were prepared by compression molding. Physical and mechanical properties of the specimens were analyzed by water absorption, thickness swelling, thermal conductivity, density, modulus of rupture and modulus of elasticity. From the results, water absorption at 1 and 24 hours was 19-47 % and 38-57 %, respectively. Thickness swell at 24 hours was 15-29%. Thermal conductivity was 0.016, 0.017 and 0.019 W/m.K when using isocyanate, urea formaldehyde and phenol formaldehyde, respectively. Density of the specimens was 770-860 kg/m3. Modulus of rapture was 255-280 MPa. Modulus of elasticity was 5.1-7.6 GPa. Physical and mechanical properties of the specimens indicated that they would be applied for roof tile and construction.