Polymers copolymer formation

In a third type of block copolymer formation. Scheme (3), the initiator s azo group is decomposed in the presence of monomer A in a first step. The polymer formed contains active sites different from azo functions. These sites may, after a necessary activation step, start the polymerization of the second monomer B. Actually, route (3) of block copolymer formation is a vice versa version of type (1). It has been shown in a number of examples that one starting bifunctional azo compound can be used for block copolymer synthesis following either path. Reactions of type (3) are tackled in detail in Section III of this chapter. 

In summary, these exploratory data suggest that the chromatographic method used could be a valuable tool for study of this polymerization reaction. Reasonable data were obtained for amount and composition of the copolymer. Formation of graft polymer and/or nitrile rich polymer was detected. More detailed chromatographic study of this batch polymerization could lead to a practical on-line monitoring method... 

Randomisation in miscible polymer blends (formation of random copolymers). 

A graft copolymer consists of a linear Polymer chain of one type to which has been grafted side-chains of a different type of polymer. The formation of a graft copolymer can be brought about by either of two general methods ... 

Transformation of epoxy resins, which are viscous liquids or thermoplastic solids, into network polymers is a result of interaction with alkali or acid substances by means of to polyaddition and ionic polymerization mechanisms.10 A resin solidified by to the polyaddition mechanism, is a block copolymer consisting of alternating blocks of resin and a hardener or curing agent. A resin solidified by the ionic mechanism is a homopolymer. Molecules of both resin and hardener contain more than one active group. That is why block copolymer formation is a result of multiple reactions between an epoxy resin and a curing agent.11... 

Using this technology, the preparation of the fifth tier, monoaldehyde dendrimer was reported.[102] Subsequently, living poly(methyl methacrylate) (PMMA, prepared by group transfer polymerization) was treated with the site-specific cascades. Polydispersi-ties determined for the copolymer were similar to those recorded for the living polymer when smaller dendrimers were used, whereas the use of larger dendrimers for copolymer formation leads to a dependence of polydispersity on the dendrimer. 

Many attempts have been made to synthesise ethylene/propylene block copolymers, referred to as polyallomers, with isospecific Ziegler-Natta catalysts. However, true block copolymers can hardly be synthesised. This is due to the short life of the growing polymer chains [68,241]. Therefore, only in a few cases, when the copolymers are synthesised by adding two comonomers sequentially and under very specific conditions in order to reduce chain transfer reactions, does unambiguous evidence for true block copolymer formation with isospecific catalysts exist [457]. 

Interchain copolymer formation Copolymers of reactive polystyrene and polymers with amide, mercaptan, epoxy, hydroxy, anhydride or carboxylic acid groups, copolymer of polypropylene grafted with maleic anhydride and nylon-6, copolymer of polyolefines and polystyrene, copolymer of EVA grafted with methacrylates and grafted polystyrene... 

The studied systems display properties typical of complex solutions. It can thus be said that the formation of the interpolymer complexes in nonionic polymer-copolymer systems occurs in solution. 

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