Free radical cross-linking

The radical-accepting ability of blacks used as stabilizers can interfere with the free-radical cross-linking of polymers. 

Free-Radical Cross-Linking with Polyunsaturated Additives... 

Of course, insulin release is not the unique target in the dehvery field. Indeed, for example, Ishihara [47] matches the problem of urea release using a non-erodible membrane. The system is constituted by a pH-sensitive membrane (copolymerization of 4-carboxyacrylanilide and methacrylate) sandwiched among a membrane containing urease immobilized in free radically cross-linked A, A -methylenebisacrylamide. System permeability with respect to a model dmg ((1,4-bis-(2-hydroxyethoxy)benzene) varies with urea concentration in the external environment. 

These observations make it highly probable that similar reactions occur when carbon black is exposed to thermally or shear-generated polymer free radicals during processing of rubber compounds or to polymeric radicals formed during vulcanization, particularly in such typically free radical cross-linking systems as peroxide or radiation. 

PNIPAAm homo- and copolymer gels with different feed compositions can be prepared by free-radical cross-linking polymerization with the monomers... 

The synthesis and structure of MQ resins have been described above. The poly(siloxane) network is traditionally derived by free-radical cross-linking of a high molecular weight PDMS polymer or gum using a peroxide catalyst, such as benzoyl peroxide or 2,4-dichlorobenzoyl peroxide. The curing reaction is performed immediately after the PSA has been coated onto a tape substrate, such as PET, PTFE, or Kapton. Uncured PSAs are supplied as a solution in an organic solvent. Some silicone PSAs also incorporate phenyl groups onto the gum portion of the adhesive to increase the use temperature. 

Finally, the unsaturated polyester is free-radically cross-linked by copolymerization with, for example, styrene or methyl methacrylate. Mixtures of the actual unsaturated polyester with these monomers are commercially known as unsaturated polyester resins. The properties of the thermosets can be matched to the application by variations in the acids, glycols, or vinyl monomers. Copolymerization with electronegative comonomers such as styrene or vinyl acetate leads, for example, to alternating copolymers, that is, to short cross-link bridges and therefore, to more rigid thermosets. Alternatively, electropositive comonomers such as methyl methacrylate form long methyl methacrylate bridges between the polyester chains and so produce more flexible polymerizates. 

Bychkova,A. V. Rosenfeld, M. A. Leonova, V. B. Lomakin, S. M. Sorokina, O. N. Kovarski, A. L. Surface modification of magnetite nanoparticles with serum albumin in dispersions by free radical cross-linking method. Russ, colloid J., 2012. 

From the point of view of elementary reaction steps, free-radical cross-linking polymerization does not differ from linear polymerization of monovinyl compounds and involves initiation, propagation and termination. However, the investigation of mono- and multifunctional monomer pol3merization kinetics up to late in the conversion process shows both common and special features of these processes that do not follow the classical kinetic scheme of polymerization which is satisfactory for the initial state of polymerization. 

Baquey, G. Moine, L. Degueil-Castaing, M. Lartigue, J.-C. Maillard, B., Decomposition of Di-tert-butyl Peroxide in Siloxane An Approach of the Free Radical Cross-Linking of Silicones. Macromolecules 2005, 38, 9571-9583. 

Elbert DL, Hubbell JA. Conjugate addition reactions combined with free-radical cross-linking for the design of materials for tissue engineering. Biomacromolecules 2001 2 430-41. 

In situ free-radical cross-linking of stationary phases coated on fused silica... 

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