Copolymer regular

Regular copolymer—These copolymers have an ordered sequence in the distribution of monomers. These are produced by controlled feeding of the monomers during copolymerization. 

A. Berlin, G. Zotti, S. Zecchin, G. Schiavon, M. Cocchi, D. Virgili, and C. Sabatini, 3,4-Ethylenedioxy-substituted bithiophene-a/r-thiophene-5,5-dioxide regular copolymers. Synthesis and conductive, magnetic and luminescence properties, J. Mater. Chem., 13 27-33,2003. 

Another aspect of seeded polymerization is that a seed may be formed from one monomer composition whereas the added monomer may be of a different composition. This may lead to core-shell latex particles. Such copolymers may have substantially different properties then regular copolymers. 

Micka et al. [169] were the first who simulated a multichain HPE system. They studied regular copolymers with alternating neutral and charged monomers (with a charge fraction of / = 1/3) in a poor solvent in the presence of monovalent counterions. The paper by Micka et al. [169] nicely demonstrated that the necklace microstructures exhibit a variety of conformational transitions as a function of polymer concentration. The end-to-end distance was found to be a nonmonotonic function of concentration and showed a strong minimum in the semidilute regime. 

Single hydrophobic-amphiphilic (HA) copolymers with the same HA composition but with different distribution of H and A units along the main hydrophobic chain were also simulated [212]. In particular, regular copolymers comprising H and A units in alternating sequence, regular multiblock copolymers composed of H and A blocks of equal lengths, and the quasirandom protein-like copolymers with a quenched primary structure were studied. These copolymers are schematically depicted in Fig. 24b,c, and d. 

Selb and Gallot [214] have demonstrated that poly(styrene)-gra/f-poly(4-vinyl-N-ethylpyridium bromide) forms unimolecular micelles in water/ methanol mixtures. These experimental data can be treated as an indirect confirmation of the simulation result [97] that sufficiently long regular copolymers with amphiphilic monomer units do form intramolecular aniso-metric micellar structures in a poor solvent. 

Moreover, the thorough analysis of globular conformations shows that this layer is almost absent near the faces of the cylinder [212]. This facilitates the formation of multiglobular aggregates in the solution of regular copolymers. 

These facts explain the more expressed tendency of regular copolymers toward aggregation. 

Consider a regular copolymer comb (Fig. 3) made of NA side branches (nA monomers in each) and NB backbone blocks (nB monomers in each). Note that usually NB = NA + 1 and that the backbone units are called blocks only for convenience. The various correlation terms involved are [22] ... 

Synthesized regular copolymers represent light-yellow solids with r spec=0.4-0.7, well soluble in va-rious organic solvents. It is found that the effect of increasing catalyst concentration (0.1-0.5 wt.% of initial compound) and reaction temperature on the molecular mass of low-molecular compounds obtained is negligible. 

The thermodynamic parameters ASP° and AHP° may also be affected by the microstructure of the resulting polymer or copolymer. In particular, low values of AHP° lead to reversible propagation, which in turn results in significant deviation of the copolymer composition as described by the terminal copolymerization model discussed below. On the other hand, the microstructure of the polymer affects ASP°, with atactic polymers and more random copolymers having higher entropies than tactic polymers and more regular copolymers, respectively. 

It is of considerable interest to examine this glucan since it is a regular copolymer containing both the (1 3)-b and the (1 4)-b linkages. Structural studies( ) on the product from Iceland moss have established the structure illustrated in Figure 12 which can be described as a poly (1 3)-e-cel lotr lose. It has to be noted that this 33% structural perturbation of cellulose leads to a drastically modified solubility since lichenan is water soluble. 

On these premises we have designed a regular copolymer consisting of a series of thienylene (low-gap sequence) and phenylene (high-gap sequence) rings linked by... 

The regular copolymers require additional structure information. Three simple examples are listed with their nomenclature in Fig. 1.19. While alternating copolymers also need only information on the concentration for full characterization, more detail is needed for block and graft copolymers. The number and length of the blocks or grafted chains and their possible distributions within and between the molecules must be known for full structural characterization. 

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