Oscillatory and viscometry studies were carried out

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Unformatted text preview: ur. The emulsion system containing 0.1 to 0.2 % of Cetearate-20 has better storage stability and higher structural integrity. 218 3rd ICYC 2010 Universiti Sains Malaysia 23rd-25th June 2010 ORAL PRESENTATION (POLYMER) POLY-O1 NEW STABILIZERS FOR POLYSTYRENE BASED ON 2-THIOACETIC-5-PHENYL-1,3,4-OXADIAZOLE Emad Yousif, Nadia Salih and Jumat Salimon School of Chemical Science and Food Technology, Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia E-mail: [email protected] The photostabilization of polystyrene (PS) films by 2-thioacetic-5-phenyl-1,3,4-oxadiazole with Sn(II), Cd(II), Ni(II), Zn(II) and Cu(II) complexes was investigated. The PS films containing concentration of complexes 0.5 % by weight were produced by the casting method from chloroform solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl and hydroxyl indices with irradiation time. The changes in viscosity average molecular weight of PS with irradiation time were also tracked (using benzene as a solvent). The quantum yield of the chain scission -6 -6 (Φcs) of these complexes in PS films was evaluated and found to range between 3.21 10 and 7.4310 . Results obtained showed that the rate of photostabilization of PS in the presence of the additive follows the trend: Ni(L)2 >Cu(L)2 >Zn(L)2 >Cd(L)2 >Sn(L)2. According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among UV absorption, peroxide decomposer and radical scavenger for photostabilizer additives mechanisms were suggested. POLY-O2 EVALUATION OF IMPACT STRENGTH AND MICRO- HARDNESS OF DENTURE BASE ACRYLIC RESIN (PMMA) PART II 1 S. H. Mohamed, T. Ajaal and Alb. M. Al-Jadi 2 2 1 Faculty of Dentistry, Al-Arab Medial Benghazi– Libya 2 Academic of Postgraduate Studies- Tripoli Libya E-mail: [email protected] Poly (methyl methacrylate) is widely used as denture base material. During fabri...
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