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Polymerization and polymer characterization of n-vinylcaprolactam

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2005
Polat, Özlem
In this study, N-vinylcaprolactam was polymerized by radiation in the solid state. The polymerization was carried out at room temperayure under vacuum and open to atmosphere respectively. The polymerization mechanism showed autoacceleration and the rate of polymerization was higher in the presence of oxygen. However the limiting conversion was 100% under vacuum conditions and 90% in the present of oxygen. This is due to the low molecular weight olgomer formation in the presence of oxygen. The polymers were characterized by FT-IR, NMR, DSC, TGA, Light Scattering, GPC, Viscosity, X_Ray and mass spectrometry methods. FT-IR and NMR results showed that polymerization proceded through the vinyl groups and caprolactam is a pendent group. DSC results show that the polymer produced could be polymerized further or crosslink by heat treatment. The Tg value for the polymerobtained from radiation induced polymerization was about 147 C. It increased to 174 C after thermal treatment. Solution properties were studied by Light Scattering, GPC and viscosity measurements. The solutionbehavioor of the polymer was highyl dependent on the molecular weight of the polymer. This effect was also the conformation of polymer in solution and the viscosity properties. Since the polymer obtained had low molecular weight a regular relation could not be obtained for the radius of gyration, hydrodynamic radius and viscosity. X-ray diffraction studies showed that the monomer structure was retained up to about 86% conversion of monomer to polymer. The chain structure of the polymer was confirmed further by mass spectroscopic results.