Polycomplex

Fig. 2.6 The moqjhological events of sporulation in Saccharomyces cerevisiae. (a) starved cell V, vacuole LG, lipid granule ER, endoplasmic reticulum CW, cell wall M, mitochondrion S, spindle pole SM, spindle microtubules N, nucleus NO, nucleolus, (b) Synaptonemal complex (SX) and development of polycomplex body (PB) along with division of spindle pole body in (c). (d) First meiotic division which is completed in (e). (f) Prepararation for meiosis II. (g) Enlargement of prospore wall, culminating in enclosure of separate haploid nuclei (h). (i) Spore coat (SC) materials produced and deposited, giving rise to the distinct outer spore coat (OSC) seen in the completed spores of the mature ascus (j). Reproduced from the review by Dickinson (1988) with permission from Blackwell Science Ltd.

As it was showm based on the example of polymerization of urea with formaldehyde in the presence of poly(acrylic acid), the product obtained interacts so strongly that it is insoluble in the common solvents. Probability of intermolecular chemical reactions increases in such systems which leads to crosslinking of the polycomplex. 

Figure 9.8. Polycomplex creation from higji molecular weight pol5nner and oligomeric molecules. Host-guest model.

Figure 9.9. Polycomplex formation from two high molecular weight polymers. Scrambled eggs model.

The polycomplex obtained by template polymerization of polyacrylamide with uracil groups onto template, from polyacrylamide with adenine groups, was found to be very stable compared with the polymer complex which was formed by mixing both polymers... 

Special type of template polycondensation product was obtained by Papisov at al Polycondensation of urea with formaldehyde in the presence of polyCacrylic acid) gives polycomplexes or polycomplex composites with various structures and properties. The... 

Figure 9.13. Schematic representation of matrix polymerization of urea and formaldehyde in the presence of PAA (a) moderately concentrated solution of PAA and monomers (monomer molecules are not indicated), (b) 1st step of the process - gel formation (composite polycomplex + excess of PAA), (c) polycomplex PAA-PFU =1 1, (d) composite polycomplex + excess of PFU. Reprinted from I. M. Papisov, 0. E. Kuzovleva, S. V. Markov and A. A. Litmanovich, Eur. PoZy/n. J.,20,195(1984),...

First step (a) represents the initial system - solution of the poly(acrylic acid) (urea and formaldehyde are not shown). Then, growing macromolecules of urea-formaldehyde polymer recognize matrix molecules and associate with them forming polycomplex. This process leads to physical network formation and gelation of the system (step b). Further process is accompanied by polycomplex formation to the total saturation of the template molecules by the urea-formaldehyde polymer (step c). Chemical crosslinking makes the polycomplex insoluble and non-separable into the components. In the final step (c), fibrilar structure can be formed by further polycondensation of excess of urea and formaldehyde. 

Template polymerization is the only way to produce polycomplexes and polycomplex composites in which one of the polymer components is insoluble and the polycomplex cannot be obtained by mixing solutions of polymers previously prepared. In this way, interpenetrating networks were obtained. 

The polycomplexes obtained by template polymerization of methacrylic acid or acrylic acid in the presence of poly(N,N,N, N - tetramethyl-N-p-xylene-ethylenediammonium dichloride) were used for spinning of fine fibers 5 to 50 pm in diameter. The fibers are soluble in water but become stable after thermal treatment at about 80°C. The polycomplex with regular structure, obtained by template polymerization, is expected to be of considerable interest for textile industry. 

Figure 11.6. Composition of polycomplex as a function of time. According to ref. 21.

A similar procedure was described by Eboatu and Ferguson. An object of analysis was the complex obtained by template polymerization of acrylic acid in the presence of poly(vinyl pyrrolidone). The polycomplex was dispersed in dry benzene and treated with diazomethane. The insoluble portion was filtered. The filtrate containing poly(methyl acrylate) was concentrated and finally dried. The insoluble fraction was scrubbed with methanol to extract polyCvinyl pyrrolidone). The residue was further washed with methanol and then dried. These three portions were characterized by IR spectroscopy. It was found that only about 70% separation of the complex is achieved. The occurrence of inseparable portion is attributed to a graft copolymer formation. For the separated... 

The mechanism of molecular recognition reactions (kinetics and mechanism of substitution and exchange reactions with participation of polycomplexes and free chains) is considered. 

Systems are considered in which, under certain conditions, matrix regeneration is possible in the process of matrix synthesis (i.e. freeing of the matrix from the polycomplex being formed) and multiple use of a single matrix for controlling the growth of the daughter chains. 

Chains, on the Structure and Properties of Polycomplexes — Products of the Matrix Reactions of Polymer Synthesis.169... 

Sufficient experimental and theoretical data have been already obtained permitting us to consider the molecular recognition ability, a fundamental property of macromolecular systems this property manifests itself under interactions where simple synthetic macromolecules (homo- and copolymers) participate, if they result in the formation of a polycomplex, i.e., a compound of the following type... 

Now add to this solution complementary polymer P which is capable of forming the equimolar (stoichiometry is not important since it must be only constant) polycomplex with P, its concentration being m < m°, then part P will bind in a polycomplex and the distribution function of P ws( x. ) remaining in the solution, normalized to m° — m, on the whole will not be identical to the initial one, i.e.,... 

Assuming that each macromolecule P is either fully bound in a polycomplex or is fully in a non-bound state, the following correlation is valid for each fraction of polymer P ... 

Parameter A denotes the normalizing multiplier, reflecting the fact that polymer P is in deficiency, i.e., that the polycomplex phase is of limited holding capacity . If this capacity of a polycomplex is unlimited then, in accordance with Boltzmann s statistics, A = 1 therefore A < 1 in the given case. 

Notes 1. In the row of reactivity, every next polymer is substituted with the preceding one in the polycomplex... 

Experimental dependencies of the stability of polycomplexes on the length of macromolecules and temperature are, in general, satisfactorily described by Eqs. (7) and (8a) 28,32). However, there are a whole number of objective reasons owing to which these equations may be used for quantitative calculation of the thermodynamic... 

Defects in the structure of a polycomplex, such as different-type loops from the unbound-in-a-complex parts of macromolecules of type ... 

The presence of defects caused by incomplete reaction in the particles has been found while comparing intra- and intermolecular reaction rates in polycomplexes obtained by mixing polymer solutions, and by matrix polymerization 461. In the latter case a polycomplex is formed simultaneously with the chain growth which is connected with the complementary macromolecule, the matrix. This process of polycomplex formation is closer to the equilibrium one — in any case there are considerably fewer obstacles here for forming an uninterrupted sequence of intermolecular bonds. That is why the rate and conversion of thermochemical reactions (which are connected with the presence or absence of defects — loops or tension in double-stranded chains of the polycomplex) depend on how the polycomplex have been obtained. After its destruction and reconstruction (e.g., by increasing and then decreasing of pH in the case of p.c. (PMA — PVPD)) the matrix polycomplex does not differ from the one obtained by mixing 46). 

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