Papers by Keyword: Polyethylene (PE)

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Authors: Yu Hua Dong, Ke Ren, Qiong Zhou
Abstract: Linear low density polyethylene (LLDPE) was chemically modified with grafting maleic anhydride (MAH) monomer on its backbone by melting blending. Nano-particles SiO2 was modified by cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) and anionic surfactant sulfosalicylic acid (SSA) and added to PE coating respectively. Measurement of membrane potential showed that the coating containing modified SiO2 nano-particles had characteristic of ion selectivity. The properties of the different coatings were investigated according to relative industrial standards. Experimental results indicated that PE coating with ion selectivity had better performances, such as adhesion strength, cathodic disbonding and anti-corrosion, than those of coating without ion selectivity. Crystal structure of the coatings before and after alkali corrosion was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). Structure of the coating without ion selectivity was damaged by NaOH alkali solution, causing mechanical properties being decreased. And the structure of the ion selective coatings was not affected.
Authors: Sriram Venkataramani, Tharanikkarasu Kannan
Abstract: A novel single-site catalyst was prepared from N-pheneyldiethanolamine and titanium tetrachloride and characterized using spectroscopic methods such as Nuclear Magnetic Resonance (NMR) spectroscopy and Infra Red (IR) spectroscopy. It was prepared insitu and used to polymerize ethylene along with methylaluminoxane (MAO) as co-catalyst. The turnover frequency for ethylene polymerization was found to be 350 g and 550g polymer/mol catalyst/h for 1 bar and at 2 bar respectively. As the turn over frequency at the studied reaction conditions is good, the present N-pheneyldiethanolamine-based catalyst is a good single-site catalyst for olefin polymerization
Authors: Ming Kuen Chang, Jia Ying Lin, Yan Huei Peng, Jian Jhih You, Yu Ming Wang
Abstract: This study have used three different montmorillonite by anionic, nonionic and ammonium chloride modifier to prepare polyethylene / montmorillonite (MMT) nanocomposites. The kneading process doped modified MMT to polyethylene, according with ASTM D638 to proceed hot-press works, and ASTM D256 to determine the izod pendulum impact resistance of plastics specimen. Prepared nanocomposites continue proceed in tensile and impact testing, finally, we observed low-density polyethylene layered silicate nanocomposites properties were improved, also found that anion modified montmorillonite had significant reinforcement effect in tensile and impact testing.
Authors: A.M.G. Pinto, A.G. Magalhães, F. Gomes da Silva, A.P.M. Baptista
Abstract: The mechanical behaviour of single lap adhesive joints was characterized, using two commercial acrylic adhesives. For this purpose the surfaces were cleaned and abraded using fine grit abrasives. The effect of temperature and moisture in the mechanical strength was, also, evaluated. For this characterization, mechanical tests were carried out according procedure and geometry foreseen by ASTM D3163-01 [1] and ASTM D4501-01 [2] standards. The results show that it is possible to get good strengths without great surface preparation. The temperature and moisture effect observed don’t seem to be relevant for the mechanical behaviour.
Authors: Kawashita Masakazu, Satomi Itoh, Kazunori Miyamoto, Rei Araki, Gikan H. Takaoka
Abstract: Polyethylene (PE) substrates were irradiated at a dose of 1×1015 ions·cm−2 by the simultaneous use of oxygen (O2) cluster and monomer ion beams. The acceleration voltage for the ion beams was 7 kV. Unirradiated and irradiated PE substrates were soaked in simulated body fluid with ion concentrations 1.5 times of those of human blood plasma (1.5SBF) for 7 days. The irradiated PE substrate formed apatite on its surface, whereas unirradiated one did not form it. This is attributed to the formation of functional groups effective for apatite nucleation, such as COOH groups, on the substrate surface by the simultaneous use of O2 cluster and monomer ion beams. In addition, the apatite-forming ability of the irradiated substrate was improved by the subsequent CaCl2 treatment. This suggests that Ca2+ ions present on the substrate surface accelerated the apatite deposition. We can conclude that apatite-forming ability can be induced on surface of polyethylene by the simultaneous use of O2 cluster and monomer ion beams.
Authors: Nikolay Djourelov, Takenori Suzuki, Chun Qing He, Yasuo Ito, Kalina Velitchkova, E. Hamada, Kenjiro Kondo
Authors: Nikola Kasálková, Kateřina Kolářová, Lucie Bačáková, Martin Pařízek, Anna Macková, Václav Švorčík
Abstract: The interaction of cells with polymers is important for their potential applications in medicine and various areas of biotechnology. Their physico-chemical surface properties strongly influence the cell morphology, adhesion and growth. Physical and chemical properties of pristine and modified polyethylene (PE) films were studied. PE was modified by Ar plasma (0–400 s, 2.0 W) and than grafted with amino acid (glycine). Structural and morphological changes of polymer were studied by goniometry and Rutherford back-scattering (RBS). The interaction of these samples with vascular smooth muscle cell (VSMC) from the rat aorta was studied. Number and morphology of the adhered and proliferated cell on the pristine and modified PE was studied in vitro method. It was found that wetting angle of the modified films decreased with exposure time. Experiments in vitro indicated that the adhesion and proliferation of VSMC is increasing function of degradation time and glycine grafting.
Authors: Refat El-Sheikhy, Mosleh Al-Shamrani
Abstract: Nanocomposite made of clay minerals and polyolefin goes through several steps. During these steps materials will have changes especially in the structure and properties. Then the final material will be of both new structure and properties. These main steps in the manufacturing process will include the stages of preparation of the material components and mixing. The structures of the materials are well characterized at each step. Then, we can understand how the processing steps will affect the structures and mechanism for producing the final nanocomposite material. The results include characterization by SEM, TEM, XRD and EDAX chemical analysis. During the processing, the energy will be changed for both of the initial materials and the final product in addition to the materials properties which will depend on the energy changes. The analysis includes the methods of calculations of energy changes. Then, design suggestions are developed for energy control to produce nanocomposite with certain energy level to carry certain amount of loads. Therefore, the study will provide possibility for pre-control of the lifetime of the produced materials.
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