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Polymerization Degree (polymerization + degree)
Selected AbstractsFree Radical Graft Copolymerization of Methyl Methacrylate onto Polyolefin Backbone: Kinetics Modeling through Model Compounds ApproachMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13-14 2009Thierry Badel Abstract The grafting of poly(methyl methacrylate) (PMMA) from poly[ethylene- co -(1-octene)] in the molten state by in situ radical polymerization of methyl methacrylate (MMA) was investigated through a kinetic modeling using a model compound approach. We resorted to pentadecane (C15H32) and 2,6,10,15,19,23-hexamethyltetracosane (Squalane, C30H62) as models for both the copolymer ethylene and octene moieties. The attention was focused on the simulation of MMA conversion and PMMA average polymerization degree according to temperature, reaction time, and initiator ratio required for the polymerization of MMA in the presence of alkoxyl radicals and alkanes. [source] Synthesis and properties of dendritic polymers based on natural amino acidsMACROMOLECULAR SYMPOSIA, Issue 1 2003Alexander Bilibin Abstract Different approaches, including polycondensation, polymerization, polymer analog condensation, and ionic binding have been investigated for synthesis of amino acid-based dendritic polymers. It was shown that a growth of dendrons generation prevents obtaining of products with high polymerization degree in polycondensation and polymerization procedures. In polymer analog condensation a growth of dendrons generation leads to considerable decrease of polymer analog reaction rate as well as substitution degree. Degree of ionic binding depends on a strength of ionogenic groups and dendrns generation. [source] Kinetics of self-condensing vinyl hyperbranched polymerization in three-dimensional spaceJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2008Xuehao He Abstract Self-condensing vinyl hyperbranched polymerization (SCVP) with A-B* type monomer is simulated applying Monte Carlo method using 3d bond fluctuation lattice model in three-dimensional space. The kinetics of SCVP with zero active energy of reaction is studied in detail. It is found that the maximal number,average and weight,average polymerization degrees and the maximal molecular weight distribution, at varying the initial monomer concentration and double bond conversion, are about 52, 190, and 3.93, respectively, which are much lower than theoretical values. The maximal average fraction of branching points is about 0.27, obtained at full conversion at the initial monomer concentration of 0.75. The simulation demonstrated the importance of steric effects and intramolecular cyclization in self-condensing vinyl hyperbranched polymerization. The results are also compared with experiments qualitatively and a good agreement is achieved. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4486,4494, 2008 [source] Gradient graft copolymers derived from PEO-based macromonomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2006Dorota Neugebauer Abstract Atom transfer radical polymerization (ATRP) of two poly(ethylene oxide) (PEO) macromonomers, with different polymerization degrees (DPn) and different end groups, was conducted in solution via the grafting through method. Selection of a PEO methacrylate with a methyl end-group (PEOMeMA, DPPEO = 23) and a PEO acrylate end-capped by a phenyl ring (PEOPhA, DPPEO = 4) for the copolymerization led to a spontaneous gradient of PEO grafts along the copolymer backbone. Such a composition was formed because of significantly different reactivities of the two PEO macromonomers. The resulting copolymer has PEOMeMA at one end of the polymer chain, gradually changing through hetero-sequences of PEOPhA at the other chain end. An increase in the initial feed ratio of PEO acrylate reduced the rate of change in the shape of the gradient. Amorphous,crystalline structure in the copolymers was demonstrated by DSC and WAXS. The mechanical measurements of copolymers consisting of an amorphous PEOPhA and crystallizable PEOMeMA segments indicated elastomeric properties in the range of a soft rubber (G, , 104 Pa, G, , G,). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1347,1356, 2006 [source] | ||||||||||