Jindabot S.,Mahidol University |
Teerachanan K.,Mahidol University |
Thongkam P.,Mahidol University |
Kiatisevi S.,Mahidol University |
And 6 more authors.
Journal of Organometallic Chemistry | Year: 2014
Preparation of the Pd(II) complexes containing 2-(4-R-1,2,3-triazol-1-yl) pyridine [R = C6H5 (1), NC5H4 (2), n-C6H13 (3)] were described. Crystal structures of 1 and 2 revealed a square planar geometry with bidentate ligand coordination to Pd using different N donor of the triazole ring. Catalytic studies indicated that 1-3 exhibited moderate to high activity for Suzuki-Miyaura coupling between aryl bromides and phenylboronic acid under mild and aerobic conditions. © 2013 Elsevier B.V. All rights reserved.
Tensile deformation of in-reactor polymer alloy with preferentially oriented crystallite in parallel and perpendicular to uniaxial stretching direction: A model case from impact-resistance polypropylene copolymer
Rungswang W.,SCG Chemicals Co. |
Plailahan K.,Thai Polyethylene Co. |
Saendee P.,SCG Chemicals Co. |
Rugmai S.,Synchrotron Light Research Institute Public Organization |
Cheevasrirungruang W.,SCG Chemicals Co.
Polymer (United Kingdom) | Year: 2013
Impact-resistance polypropylene copolymer (IPC) has been known as multiphase material in which ethylene-propylene rubber (EPR) is dispersed in homo-PP matrix (hPP). Although, the IPC has been commercially produced for several decades, the knowledge of its microstructural change under tensile stretch has not been well established. The present work, for the first time, shows the crystallite evolution of the IPC with preferentially oriented crystal lamellae in both perpendicular and parallel to stretching direction (SD). The IPC with lamella oriented perpendicular to SD exhibits higher strength and strain at break than the others. Small angle X-ray scattering (SAXS) and wide angle X-ray diffraction (WAXD) techniques reveal that the elongation of the lamellar fibril is the main mechanism for the lamella oriented perpendicular to SD while the fibril fracture is for the lamella oriented parallel to SD. © 2013 Elsevier Ltd. All rights reserved.
Rojanotaikul P.,Chulalongkorn University |
Ayudhya S.K.N.,Thai Polyethylene Co. |
Charoenchaidet S.,Thai Polyethylene Co. |
Faungnawakij K.,National Science and Technology Development Agency |
Soottitantawat A.,Chulalongkorn University
Engineering Journal | Year: 2012
Polyethylene (PE) is indispensable materials in daily lives. To produce PE, the catalyst was needed in the reaction. Ziegler-Natta catalysts were mostly used which consisted of TiCl 4 on the MgCl 2 supports. Polyethylene particle was reported to replicate the shape of the catalyst particles or catalyst support particles. Therefore, the MgCl 2 supports need to satisfy various requirements regarding particle morphology such as shape, particle size with uniform size distribution as well as the porosity. In this research, the preparation of MgCl 2 particles from irregular shape of anhydrous MgCl 2 by spray drying method was studied. The moisture was reported as the poison of the catalyst, so the unusual close loop spray drying under N 2 conditions was used in this study. The different types of alcohol, ethanol, n-propanol and n-butanol as solvent which was used to dissolve MgCl 2 before feeding through the spray drying on the particle properties were investigated. The amount of residual alcohol (alcoholic hydroxyl group content), morphology, specific surface area, porosity and crystallinity were determined by GC method, scanning electron microscope (SEM), N 2 sorption analyzer and X-ray diffraction (XRD), respectively. The results revealed that spray drying process can produce the porous anhydrous MgCl 2 particles which have rough surface, higher porosity and lower crystallinity than original anhydrous MgCl 2.
Polrut W.,Chulalongkorn University |
Boonliang B.,Thai Polyethylene Co. |
Tanthapanichakoon W.,Thai Polyethylene Co. |
Damronglerd S.,Chulalongkorn University
International Polymer Processing | Year: 2011
This study dealt with operating windows and scale-up rules of a compounding twin screw extruder for polypropylene (PP) /multi-walled carbon nanotubes (MWCNT) composites with required conductivity. In this study we showed that the experimentally obtained boundary line separating either conductive or non-conductive region is essentially linear, and thus the operating windows, in which the PP/MWCNT composite is consistently conductive with statistically 95% reliability level, can be drawn as a triangle. The use of this triangle rule of the operating windows to achieve required volume resistivity was proposed. With similarity of the length and diameter ratio (L/ D) and screw configuration between small (laboratory-scale) and large (production-scale)) extruders, our investigation revealed that the most effective scale-up factors for the volume resistivity are (D large/D small) 3 for the throughput, and (D small/D large) for the screw speed as a new scale-up rule generally valid for any machine size. © Carl Hanser Verlag GmbH & Co. KG.
Hongmanee G.,Chulalongkorn University |
Sripothongnak S.,Thai Polyethylene Co. |
Jongsomjit B.,Chulalongkorn University |
Praserthdam P.,Chulalongkorn University
Journal of Applied Polymer Science | Year: 2014
In this work, the effects of three types of cocatalyst having different alkyl groups, such as triethylaluminium (TEA), triisobutylaluminum (TiBA), and trioctylaluminium (TnOA), and their concentrations on the catalytic activity and polymer properties were investigated for the Ziegler-Natta catalyst containing alkoxide species. The drastic escalation of catalytic activity was observed when the ratio of Al/Ti was increased only for TEA because of its good diffusivity as proven by the electron spin resonance technique. Moreover, it was found that the characteristic of the alkyl group in cocatalyst affected on the chain transfer ability. The chain transfer ability of TnOA was found to be equal to the TiBA in spite of its concentration was higher. By the way, the cocatalyst types and their concentrations did not affect on the variety of active sites as seen in molecular weight distribution of polymer. © 2014 Wiley Periodicals, Inc.
Rungswang W.,Thai Polyethylene Co. |
Saendee P.,Thai Polyethylene Co. |
Thitisuk B.,Thai Polyethylene Co. |
Pathaweeisariyakul T.,Thai Polyethylene Co. |
Cheevasrirungruang W.,Thai Polyethylene Co.
Journal of Applied Polymer Science | Year: 2013
Impact polypropylene copolymer (IPC) has been known as a multiphase material in which an ethylene-propylene (EP) random copolymer, serves as toughening component, is dispersed in the homo-polypropylene hPP matrix. The crystalline EP copolymer (cEP) is another component whose role and microstructural effect on the IPC properties has not been well understood. This work reveals the relationship between the microstructure of cEP and the mechanical properties, that is, impact and tensile resistance, of IPC. We clarify that IPC comprising high contents of cEP with long homo-PP segment can extend the elongation at break while cEP with high content of homo-PE segment contributes to high impact strength. Mechanisms for both of these processes have been proposed. © 2012 Wiley Periodicals, Inc.
Kamonsatikul C.,Mahidol University |
Khamnaen T.,Thai Polyethylene Co. |
Phiriyawirut P.,Thai Polyethylene Co. |
Charoenchaidet S.,Thai Polyethylene Co. |
Somsook E.,Mahidol University
Catalysis Communications | Year: 2012
Magnetic iron-oxide nanoparticles stabilized by imine or amine ligands containing ferrocene moieties were synthesized and characterized by FTIR, XRD, AAS, TEM, vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. The oxidation of benzyl alcohol was carried out in the presence of the synthesized magnetic nanoparticles with or without ferrocene moieties as nanocatalysts and H 2O 2 as oxidant. The synergistic activities between magnetic nanoparticles and ferrocene moieties in the stabilizing ligands were observed in this nanocatalysis. It turned out that the conversions of benzyl alcohol and the selectivities of benzaldehyde in the nanocatalytic systems with magnetic iron-oxide nanoparticles stabilizing by ligands containing ferrocene moieties were enhanced significantly than the ferrocene-free nanocatalytic systems. The nanocatalysis was proposed to be proceeded via first adsorption of benzyl alcohol on the surface of nanoparticles and then Fenton-typed reactions operating at both magnetic iron-oxide nanoparticles and ferrocene moieties. Ferrocene moieties play an important role in the nanocatalysis for the enhanced selectivity of benzaldehyde by their synergistic interactions to magnetic iron-oxide nanoparticles. Accordingly, the enhanced catalytic activity of nanocatalysts can be achieved by tuning the structure of stabilizing ligands surrounding to nanoparticles. © 2012 Elsevier B.V. All rights reserved.