Showing papers by "Abu Bakar published in 2005"

Water absorption and hygrothermal aging study on organomontmorillonite reinforced polyamide 6/polypropylene nanocomposites

Abstract: The water absorption and hygrothermal aging behavior of organomontmorillonite (OMMT) reinforced polyamide 6/polypropylene (PA6/PP ratio = 70/30), with and without maleated PP (MAH-g-PP), was studied at three different temperatures (30, 60, and 90°C). The water absorption and hygrothermal aging response of the composites was studied and analyzed by tensile tests and morphology assessment (scanning electron microscopy and transmission electron microscopy), indicating the effect of the immersion temperature, OMMT, and MAH-g-PP compatibilizer. The mathematical treatment used in analyzing the data was the single free phase model of diffusion, which assumed Fickian diffusion and utilized Fick's second law of diffusion. The kinetics of water absorption of the PA6/PP nanocomposites conformed to Fickian law behavior, whereby the initial moisture absorption follows a linear relationship between the percentage gain at any time t and t1/2 (the square root of time), followed by saturation. It was found that the equilibrium moisture content and the diffusion coefficient are dependent on the OMMT loading, MAH-g-PP concentration, and immersion temperatures. Both the tensile modulus and strength of the PA6/PP nanocomposites deteriorated after being exposed to hygrothermal aging. MAH-g-PP acted as a good compatibilizer for PA6/PP/OMMT nanocomposites, which was attributed to its higher retention ability in modulus and strength (in the wet and redried states), lower equilibrium moisture content, and reduced water diffusivity of the nanocomposites. Morphological sketches for both uncompatibilized and MAH-g-PP compatibilized PA6/PP/OMMT nanocomposites, toward water uptake are proposed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 780–790, 2005

Effects of Chemical Modification of Paper Sludge Filled Polypropylene (PP)/Ethylene Propylene Diene Terpolymer (EPDM) Composites

Abstract: The effects of surface treatment of paper sludge (PS) with acrylic acid (esterification) and acetic acid (acetylation) on torque, stabilization torque, mechanical properties, water absorption, morphology, and thermal properties of PP/EPDM/PS composites were studied. It was found that esterified and acetylated composites exhibit higher stabilization torque than untreated composites. The esterification and acetylation treatment have improved the tensile strength, elongation at break, and Young's modulus but have reduced the water absorption of composites. The scanning electron microscopy (SEM) study of the tensile fracture surface of the esterified and acetylated composites indicates that the presence of acrylic acid and acetic acid increased the interfacial interaction between paper sludge and PP/EPDM matrix. The esterification and acetylation treatment also increase the thermal stability and crystallization of PP/EPDM/PS composites. It was found that paper sludge acts as a nucleation agent in the presence...

The Effect of Paper Sludge Content and Size on the Properties of Polypropylene (PP)-Ethylene Propylene Diene Terpolymer (EPDM) Composites:

Abstract: The effect of paper sludge content and size on the processibility, mechanical properties, swelling behavior and morphology of PP-EPDM composites were examined. Results show that the increasing content of paper sludge in composites has increased the Young’s modulus and water absorption but decreased the tensile strength and elongation at break. At a similar filler content, PP-EPDM composites with the smallest size show the highest mechanical properties but the lowest water absorption resistance. SEM tensile fracture surface of composites show that the smallest size of paper sludge has better filler-matrix interaction than the larger size of paper sludge. Thermogravimetric analysis showed that the increase of paper sludge content has increased the thermal stability of PP-EPDM composites particularly at temperatures above 500 C.

The Effect of Compatibilizer and Coupling Agent on the Properties of Paper Sludge Filled Polypropylene (PP)/Ethylene Propylene Diene Terpolymer (EPDM) Composites

Abstract: Paper sludge-polypropylene (PP)–ethylene propylene diene terpolymer (EPDM) composites were developed in this study. The paper sludge was used as a filler in PP/EPDM blends, and maleic anhydride-grafted PP (MAPP) and LICA were used as a compatibilizer and a coupling agent, respectively. The mechanical properties, thermal behavior, water absorption, morphology, and the compatibilization mechanism of the composites were investigated. The better mechanical properties (e.g., tensile strength and tensile modulus) and lower water absorption with the addition of both compatibilizer and coupling agent were due to the improvements in the wetting of filler surface and better filler matrix interaction of composites as evidenced from scanning electron microscopy studies. It was found that paper sludge acted as a nucleation agent with the presence of MAPP and LICA. The addition MAPP and LICA also increased the crystallization of PP and thermal stability of PP/EPDM/PS composites. The interaction between MAPP an...

The effect of polyethylene-octene elastomer on the morphological and mechanical properties of polyamide 6/polypropylene nanocomposites

Abstract: Rubber-toughened nanocomposites (RTNC) consisting of ternary blends of polyamide 6 (PA6), polypropylene (PP) and polyethylene-octene elastomer (POE) containing 4 wt% of organophilic modified montmorillonite were produced by melt compounding followed by injection moulding. The blend composition was kept constant (PA6/PP=70/30 parts by weight) while the POE content was varied between 5 and 20 w-t%. Maleated PP (PP-g-MA) was used as was used as compatibilizer. The morphology of the RTNC was studied by scanning electron microscopy and X-ray diffraction (XRD). The mechanical properties of RTNC were studied through tensile, flexural, Izod impact and facture toughness properties. While the tensile and flexural properties were found to decrease with the increasing concentration of POE, the toughness was significantly enhanced as compared to the neat PA6/PP blends. In general, the blends containing 10-15 wt% of POE had the best balance of stiffness, strength and toughness. The addition of 30 wt% of PP in the PA6 matrix improved the compatibility between PA6 and the rubber phase. XRD established that the organoclay was well dispersed (exfoliated) and preferentially embedded in the PA6 phase.

A comparative study on the effects of paper sludge and kaolin on properties of polypropylene/ethylene propylene diene terpolymer composites

Abstract: he effects of paper sludge (PS) and kaolin on properties of PP/EPDM composites were examined. The mechanical properties, morphology, water absorption, and thermal properties were investigated. At a similar filler loading, PP/EPDM/kaolin composites show higher mechanical properties (such as tensile strength and elongation at break, except Young's modulus), lower water absorption, and better thermal stability compared to PP/EPDM/PS composites. However PP/EPDM/PS composites exhibit better Young's modulus and percentage of crystallinity than PP/EPDM/kaolin composites. SEM of tensile fracture surfaces of composites show that the PP/EPDM/kaolin composites have better filler dispersion and filler-matrix interaction than PP/EPDM/PS composites.

Microstructure and fracture behavior of (co)injection‐molded polyamide 6 composites with short glass/carbon fiber hybrid reinforcement

Abstract: The mechanical and fracture properties of injection molded short glass fiber)/short carbon fiber reinforced polyamide 6 (PA 6) hybrid composites were studied. The short fiber composites of PA 6 glass fiber, carbon fiber, and the hybrid blend were injection molded using a conventional machine whereas the two types of sandwich skin–core hybrids were coinjection molded. The fiber volume fraction for all formulations was fixed at 0.07. The overall composite density, volume, and weight fraction for each formulation was calculated after composite pyrolysis in a furnace at 600°C under nitrogen atmosphere. The tensile, flexural, and single-edge notch-bending tests were performed on all formulations. Microstructural characterizations involved the determination of thermal properties, skin–core thickness, and fiber length distributions. The carbon fiber/PA 6 (CF/PA 6) formulation exhibits the highest values for most tests. The sandwich skin-core hybrid composites exhibit values lower than the CF/PA 6 and hybrid composite blends for the mechanical and fracture tests. The behaviors of all composite formulations are explained in terms of mechanical and fracture properties and its proportion to the composite strength, fiber orientation, interfacial bonding between fibers and matrix, nucleating ability of carbon fibers, and the effects of the skin and core structures. Failure mechanisms of both the matrix and the composites, assessed by fractographic studies in a scanning electron microscope, are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 957–967, 2005

Effects of compatibilizer and testing speed on the mechanical and morphology behaviors of co-continuous amorphous copolyester-polyoxymethylene blends

Abstract: Co-continuous amorphous copolyester (PETG)/polyoxymethylene (POM) (50/50 wt%/wt%) blends were prepared using a twin screw extruder followed compression molding. Two types of thermoplastic polyurethane (TPU) (i.e., polyester-based and polyether-based) were used to compatibilize the blends system. The thermal properties were characterized by using differential scanning calorimetry (DSC). The mechanical properties of the co-continuous PETG/POM blends were studies through flexural and single-edge notch tensile test (SEN-T). The SEN-T test was performed at three different testing speeds; 1, 100, and 500 mm/min. Scanning electron microscope (SEM) was used to access the fracture surface morphology. The flexural strength of the PETG/POM blends was decreased in the presence of TPU. This was attributed to the elastomeric nature of the TPU. The compatibilizing effects of TPU on the PETG/POM blends were proven by moderate improvement in the fracture toughness and confirmed by the SEM observation. The SEN-T fractured surface of the compatibilized blends showed gross matrix shear yielding as compared to the uncompatibilized system. The Kc values of the PETG/POM blends decreased as the testing speed increased. The optimum toughening effect was observed in PETG/POM blends compatibilized with polyether-based TPU at testing speed of 100 mm/min. The polyether-based TPU is a more efficient compatibilizer, because the amount required is one-half that of the polyester-based counterpart to achieve the same Kc value. This was attributed to the elastomeric nature of the polyether-based TPU. The softer nature of polyether-based TPU could provide better toughening effect than the polyester-based TPU, which is relatively harder in nature. POLYM. ENG. SCI., 45:710–719, 2005. © 2005 Society of Plastics Engineers