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Papers by Kitti Ongwongsakul

Research paper thumbnail of Comparative behavior of in situ silica generation in saturated rubbers: EPDM and hydrogenated natural rubber

Journal of Applied Polymer, 2017

Role of carbon-carbon double (C@C) bonds content and their position in ethylene-propylene diene t... more Role of carbon-carbon double (C@C) bonds content and their position in ethylene-propylene diene ter-polymer (EPDM), hydrogenated natural rubber (HNR) and natural rubber (NR) on in situ silica formation using tetraethoxysilane (TEOS) as a silica precursor is comparatively investigated. Glass transition temperature (T g) reflecting rubber chain flexibility is found as an important factor for in situ silica generation via swelling method. Despite of similar solubility parameters, NR has higher TEOS-swelling degree resulting in the higher in situ silica content (30.8 phr) than EPDM (3.50 phr) and HNR (10.4-17.6 phr) due to the higher T g of EPDM and HNR providing the less chain flexibility to be swollen in TEOS solution. The morphological analysis implies that C@C bonds in saturated rubbers may be agglomeration sites for in situ silica particles. For practical applications, saturated rubbers containing in situ silica/NR vulcanizates showed the improvement of mechanical properties and resistance of thermal and ozone degradation.

Research paper thumbnail of Morphology and structure of modified oil palm empty fruit bunch cellulose fibre

Advanced Materials Research, 2010

Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler i... more Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler in polymer composites. Surface modification of OPEFB fibre was aimed enhancing inter-phase adhesion with a poly(lactic acid) matrix. In this study, the OPEFB fibres were pre-treated in a sodium hydroxide solution. Surface compositions and thermal stability of the fibres were studied using ATR-FTIR and TGA techniques, respectively. The pre-treatment resulted in the removal of non-cellulosic components leaving purer fibres. In addition, an acetylation of OPEFB cellulose fibres by acetic anhydride was conducted under solvent free condition at room temperature (30 °C). The acetylation reaction was catalyzed by iodine. The degree of substitution monitored by solid state 13C NMR depended upon reaction time and molar ratio of OPEFB cellulose and acetic anhydride. Crystalline structure and morphology of the partial acetylated fibres were investigated using WAXD and SEM, respectively.

Research paper thumbnail of Morphology and structure of modified oil palm empty fruit bunch cellulose fibre

Advanced Materials Research, 2010

Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler i... more Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler in polymer composites. Surface modification of OPEFB fibre was aimed enhancing inter-phase adhesion with a poly(lactic acid) matrix. In this study, the OPEFB fibres were pre-treated in a sodium hydroxide solution. Surface compositions and thermal stability of the fibres were studied using ATR-FTIR and TGA techniques, respectively. The pre-treatment resulted in the removal of non-cellulosic components leaving purer fibres. In addition, an acetylation of OPEFB cellulose fibres by acetic anhydride was conducted under solvent free condition at room temperature (30 °C). The acetylation reaction was catalyzed by iodine. The degree of substitution monitored by solid state 13C NMR depended upon reaction time and molar ratio of OPEFB cellulose and acetic anhydride. Crystalline structure and morphology of the partial acetylated fibres were investigated using WAXD and SEM, respectively.

Research paper thumbnail of Comparative behavior of in situ silica generation in saturated rubbers: EPDM and hydrogenated natural rubber

Journal of Applied Polymer, 2017

Role of carbon-carbon double (C@C) bonds content and their position in ethylene-propylene diene t... more Role of carbon-carbon double (C@C) bonds content and their position in ethylene-propylene diene ter-polymer (EPDM), hydrogenated natural rubber (HNR) and natural rubber (NR) on in situ silica formation using tetraethoxysilane (TEOS) as a silica precursor is comparatively investigated. Glass transition temperature (T g) reflecting rubber chain flexibility is found as an important factor for in situ silica generation via swelling method. Despite of similar solubility parameters, NR has higher TEOS-swelling degree resulting in the higher in situ silica content (30.8 phr) than EPDM (3.50 phr) and HNR (10.4-17.6 phr) due to the higher T g of EPDM and HNR providing the less chain flexibility to be swollen in TEOS solution. The morphological analysis implies that C@C bonds in saturated rubbers may be agglomeration sites for in situ silica particles. For practical applications, saturated rubbers containing in situ silica/NR vulcanizates showed the improvement of mechanical properties and resistance of thermal and ozone degradation.

Research paper thumbnail of Morphology and structure of modified oil palm empty fruit bunch cellulose fibre

Advanced Materials Research, 2010

Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler i... more Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler in polymer composites. Surface modification of OPEFB fibre was aimed enhancing inter-phase adhesion with a poly(lactic acid) matrix. In this study, the OPEFB fibres were pre-treated in a sodium hydroxide solution. Surface compositions and thermal stability of the fibres were studied using ATR-FTIR and TGA techniques, respectively. The pre-treatment resulted in the removal of non-cellulosic components leaving purer fibres. In addition, an acetylation of OPEFB cellulose fibres by acetic anhydride was conducted under solvent free condition at room temperature (30 °C). The acetylation reaction was catalyzed by iodine. The degree of substitution monitored by solid state 13C NMR depended upon reaction time and molar ratio of OPEFB cellulose and acetic anhydride. Crystalline structure and morphology of the partial acetylated fibres were investigated using WAXD and SEM, respectively.

Research paper thumbnail of Morphology and structure of modified oil palm empty fruit bunch cellulose fibre

Advanced Materials Research, 2010

Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler i... more Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler in polymer composites. Surface modification of OPEFB fibre was aimed enhancing inter-phase adhesion with a poly(lactic acid) matrix. In this study, the OPEFB fibres were pre-treated in a sodium hydroxide solution. Surface compositions and thermal stability of the fibres were studied using ATR-FTIR and TGA techniques, respectively. The pre-treatment resulted in the removal of non-cellulosic components leaving purer fibres. In addition, an acetylation of OPEFB cellulose fibres by acetic anhydride was conducted under solvent free condition at room temperature (30 °C). The acetylation reaction was catalyzed by iodine. The degree of substitution monitored by solid state 13C NMR depended upon reaction time and molar ratio of OPEFB cellulose and acetic anhydride. Crystalline structure and morphology of the partial acetylated fibres were investigated using WAXD and SEM, respectively.

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