Macromolecules length

One of the prime objectives of the statistical chemistry of these polymers is establishing the dependence of their composition inhomogeneity on a macromolecule length l and on the reaction system parameters. A quantitative measure of this inhomogeneity is the dispersion (Eq. 2) of the composition distribution... 

If Rfl < D, from the solution of Eq. (3.6) and the general expression for GN [see Eq. (3.2)] it is easy to see that also this case Kd is equal to unity. Thus, in CC, the retention volumes of non-functional molecules, in which all units have the same energy of interaction with the pore walls, depend neither on the macromolecule length nor on the size of stationary phase pores... 

Pokrovskii VN, Pyshnograi GV (1988) Dependence of viscoelasticity of concentrated polymer solutions upon polymer concentration and macromolecule length. Vysokomolek Soedin B 30 35-39 (in Russian)... 

The decoration of the ribbon structure with various substituents has appeared as a crucial step for obtaining sufficient polymer solubility. On the other hand, the presence of the long alkyl or alkoxy substituents typically used may have unwanted consequences (1) the presence of lateral substituents drastically changes the mol ular dimensions of the macromolecules (length/ width ratio) the mechanical and rheological properties, as well as the chemical... 

It has been found out that the effects, related either to the change in the macromolecule length or to the folding degree, do not affect the ozon-olysis in solution. Probably this is due to the fact that the reaction is carried out in elastomeric solutions, in which the macromolecules are able to do free intramolecular movements and they do not react with adjacent macromolecules. Moreover, the rate of macromolecules reorganization is probably higher than the rate of their reaction with ozone as the experiment does not provide any evidence for the effects of the change in the parameters mentioned above [29],... 

Work to further expand the reptation-tube model has been explored. Pokrovski (2008), for example, has shown that the underlying stochastic motion of a macromolecule leads to two modes of motion, namely, reptative and isotropically diffusive. There is a length of a macromolecule M = lOM where is the macromolecule length between adjacent entanglements above which macromolecules of a melt can be regarded as obstacles to motions of each other and the macromolecules reptate. The transition to the reptation mode of motion is determined by both topological restriction and the local anisotropy of the motion. 

The value of InZ) is connected with the thickness of the adsorbed layer. Therefore, we suggested that it depends on the macromolecule length of on the polymerization degree and the nmnber of link atoms in the polymer backbone (e.g., n = 2 for polystyrene or polyethylene, = 4 for polybutadiene). Therefore, we can write the linear relationship as... 

The ROP of six-membered cyclic carbonates with nucleophilic initiators is a chain reaction in which, besides initiation and propagation reactions, transesterification reactions can also take place (Scheme 32).Intramolecular nucleophile (e.g., alkoxide) attacks on carbonyl carbon atom (backbiting) lead to cyclic oligomers, while intermolecular transesterifica-tion leads to a change of the macromolecule length with the consequence that, at equilibrium, the most probable distribution of the molecular weight is obtained (Scheme 32). 

The dependence of the matter properties on the macromolecule length (or the number of chain links) was chosen as a core characteristic distinguishing homologous rows in this method. It is a principal choice. It proved to be effective and showed us the way to systematic analysis of the term oligomer . 

In other words, if inequality (2.20) is accepted, the macromolecular system is a classical polymer system and no specific properties related to the fmiteness of the macromolecules length can appear in this system. 

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