Homopolymer copolymer mixtures, multicomponent

Appendix A Multicomponent Random Phase Approximation for Homopolymer and Copolymer Mixtures... 

This generalization of de Gennes formula to multicomponent homopolymer and copolymer blends can describe a wide variety of situations. After a slight generalization (described in Appendix B) it can also, describe the case of pure copolymer mixtures whereby a copolymer has to be shared between M and R. Using Appendix A, one could obtain this limit (pure copolymer mixtures) by... 

EXA (exact) search retrieves the input stmcture and its stereoisomers, homopolymers, ions, radicals, and isotopicaHy labeled compounds. EAM (family) search retrieves the same stmctures as EXA, plus multicomponent compounds, copolymers, addition compounds, mixtures, and salts. SSS (substmcture) search uses a range of possible substituents and bonds in the input stmcture. CSS (closed substmcture) search is a more restrictive... 

We consider an incompressible (m-l-1) multicomponent mixture of polymers consisting of m different types of polymer chains within a matrix referred to as 0 . Components may be either homopolymers of a given chemical species or, e.g. homopolymer sections in block copolymers. Hydrogenated and deuterated species of the same homopolymer are considered as different components. In this context a diblock copolymer is a two-component polymer system. A mixture of partially protonated diblock chains hA-dB with deuterated diblock chains is consequently regarded as a four-component system. 

We now consider the behavior of multicomponent mixtures where we add an A-C copolymer to a blend of A and B homopolymers. Our objective was to study the effect of attractive interactions between B and C monomers (i.e., X < 0) on interfacial properties and microphase separation. The complexity in these mixtures is the fact that their phase behavior is governed by three x parameters Xab XaC ... 

We have so far considered free-radieal polymerizations where only one monomer is used and the product is a homopolymer. The same type of polymerization can also be carried out with a mixture of two or more monomers to produce a polymer product that contains two or more different mer units in the same polymer ehain. The polymerization is then termed a copolymerization and the product is termed a copolymer. Monomers taking part in copolymerization are referred to as comonomers. The simultaneous polymerization of two monomers is known as binary copolymerization and that of three monomers as ternary copolymerization, and so on. The term multicomponent copolymerization embraces all such cases. The relative proportions of the different mer units in the copolymer chain depend on the relative eoneentrations of the eomonomers in the feed mixture and on their relative reactivities. This will be the main subjeet of our diseussion in this chapter. 

Information about the monomeric composition and structure can be obtained with pyrolysis MS but sequence information is lost [46]. The method was used in several applications, such as structural identification of homopolymers, differentiation of isomeric structures, copolymer composition and sequential analysis, identification of oligomers formed in the polymerization reactions, and identification of volatile additives contained in polymer samples [47]. One of the main challenges of the technique is the identification of the products in the spectrum of the multicomponent mixture produced by thermal degradation. 

Elastic Coherent Scattering From Multicomponent Systems- Application to Homopolymer Mixtures and Copolymers, Macromolecules. 18, 986-993, (1985). 

De Gennes PG (1979) Scaling concepts in polymer physics Cornell University Press, Ithaca Benoit H, Wu W, Benmouna M, Mozer B, Bauer B, Lapp A (1985) Elastic coherent scattering from multicomponent systems applications to homopolymer mixtures and copolymers. Macromolecules 18 986-993... 

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