Grafting internal

Merika, P Quality control of freeze dried tissue grafts. International Institute of Refrigeration , Com. Cl, p. 102-105, Paris, 1983... 

If a linear mbber is used as a feedstock for the mass process (85), the mbber becomes insoluble in the mixture of monomers and SAN polymer which is formed in the reactors, and discrete mbber particles are formed. This is referred to as phase inversion since the continuous phase shifts from mbber to SAN. Grafting of some of the SAN onto the mbber particles occurs as in the emulsion process. Typically, the mass-produced mbber particles are larger (0.5 to 5 llm) than those of emulsion-based ABS (0.1 to 1 llm) and contain much larger internal occlusions of SAN polymer. The reaction recipe can include polymerization initiators, chain-transfer agents, and other additives. Diluents are sometimes used to reduce the viscosity of the monomer and polymer mixture to faciUtate processing at high conversion. The product from the reactor system is devolatilized to remove the unreacted monomers and is then pelletized. Equipment used for devolatilization includes single- and twin-screw extmders, and flash and thin film evaporators. Unreacted monomers are recovered for recycle to the reactors to improve the process yield. 

The presence of methylenic bands shifted at higher frequency in the very early stages of the polymerization reaction has also been reported by Nishimura and Thomas [114]. A few years later, Spoto et al. [30,77] reported an ethylene polymerization study on a Cr/silicalite, the aluminum-free ZSM-5 molecular sieve. This system is characterized by localized nests of hydroxyls [26,27,115], which can act as grafting centers for chromium ions, thus showing a definite propensity for the formation of mononuclear chromium species. In these samples two types of chromium are present those located in the internal nests and those located on the external surface. Besides the doublet at 2920-2850 cm two additional broad bands at 2931 and 2860 cm are observed. Even in this favorable case no evidence of CH3 groups was obtained [30,77]. The first doublet is assigned to the CH2 stretching mode of the chains formed on the external surface of the zeolite. The bands at 2931 and... 

GVHD Graft-versus-host disease IJ Internal jugular... 

Coronary artery bypass graft surgery Thoracic surgery whereby parts of a saphenous vein from a leg or internal mammary artery from the arm are placed as conduits to restore blood flow between the aorta and one or more coronary arteries to bypass the coronary artery stenosis (occlusion). 

Scheier, M. F., K A. Matthews, J. F. Owens, R. Schulz, M. W. Bridges, G. J. Magovem and C. S. Carver, Optimism and Rehospitalization after Coronary Artery Bypass Graft Surgery , Archives of Internal Medicine 159, no. 829-35 (1999)... 

G. Forat, J.-M. Mas, L. Saint-Jalmes (Rhone-Poulenc Chimie). Method for Grafting a Substituted Difluoromethyl Group to a Compound Containing an Electrophilic Group with Microwave Irradiation. PCT International Application WO 5, 609,1998 (FR Application 96/ 9,754, 1 Aug 1996) Chem. Abstr. 1998, 128, 166999u. 

The preparation of monoliths with polyNIPAAm chains grafted to the internal pore surface was discussed previously. The extended solvated polyNIPAAm-chains that are present below the lower critical solution temperature of this particular polymer are more hydrophilic, while the collapsed chains that prevail above the lower critical solution temperature are more hydrophobic. In contrast to isothermal separations in which the surface polarity remains constant throughout the run [ 136], HIC separation of proteins can be achieved at constant salt concentrations (isocratically) while utilizing the hydrophobic-hydrophilic... 

For internal graft polymerization or grafting on to polymers reactive to radical attack, inhibition by oxygen is not a serious problem. However, surface photografting of polyolefins in an open system is very inefficient. The results in Figure 13 indicate that oxygen diffused through or in OPP film is an efficient retarder. 

Hill, C.A.S. and etin, N.S. (2000). Surface activation of wood for graft polymerisation. International Journal of Adhesion and Adhesives, 20, 71-76. 

Stone, C. 2003. Low-cost PEM based on radiation induced graft polymerization. Fifth International Symposium on New Materials for Electrochemical Systems, Montreal. 

GrafTech International. 2008. Flow field plates (EFPs). http //www.graft-echaet.com/GRAFCELL/GRAFCELL-Products/Flow-Field-Plates-(FFP).aspx (accessed Dec. 20, 2008). 

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