Polymer comb-like polymers

The synthesis of comb-like polymers with regular branching (in contrast to random branching) has been performed in the following way 91) A linear polystyrene precursor fitted with carbanionic sites at both ends is reacted first with 1,1-diphenylethylene (to decrease the nucleophilicity of the sites) and then with a calculated amount of triallyloxytriazine to get chain extension. Each triazine residue still carries one allyloxy... 

The same procedure can be employed to make well defined comb-like polymers Living polystyrene can be grafted onto a partially chloromethylated polystyrene89 146), or onto a random copolymer of styrene and methyl methacrylate containing less than 10% of the latter monomer I48). 

Wide angle X-ray diffraction, WAXD, studies on the PHAs from octanoic acid (PHA-OCT), nonanoic acid (PHA-NON), and decanoic acid (PHA-DEC) showed that these polymers had the same features as synthetic comb-like polymers [54]. PHA-OCT is the most crystalline (AHm = 8.3 cal/g) and PHA-HEX (the PHA from hexanoic acid) is amorphous, while PHA-HEP (the PHA from hep-tanoic acid) has a very low degree of crystallinity (AHm= 1.3 cal/g). The degrees of crystallinity of PHA-OCT and PHA-NON were determined to be 20 and 30%,... 

Monomer Iniferter C=C-R-X > -C M) R-fM X Comb-like polymer, Graft copolymer... 

Plate, N. A., Shibaev, V. P. Comb-Like Polymers and Liquid Crystalls (in Russian), Moscow Khimiya 1980... 

A synthetic pathway that appeared to be most convenient and promising for the synthesis of LC polymers was proposed and proved in Moscow State University in 19736,8 10) and involved the use of so called comb-like polymers containing long paraffinic fragments in each monomer unitl2,33) (Fig. 2). Macromolecules of comb-like polymers are constituted of two types of structural units — the main chains and the side chains. Their behaviour is mutually dependent as they are chemically linked and at the same time both parts are sufficiently independent because the side chains are long enough. 

As the formation of LC phase in comb-like polymers is predetermined by the interaction of mesogenic groups, it would have seemed, that the temperature range of LC state for such systems should not depend on the length of the main chain, i.e. on the degree of polymerization (DP). However, studies 44,49) on the dependence of Tc] on DP carried out for some polyacrylic and polymethacrylic derivatives of cyanobiphenyl, as well as for polyparabiphenylacrylate 51 (Fig. 5), have shown that... 

Thus, polymers with mesogenic groups in side chains form structural mesophases of the same types as low-molecular liquid crystals. This makes it possible to apply traditional mesophase classification for the description of the structure of LC polymers. At the same time, the structure of some of comb-like polymers (see Table 5) considered as crystalline, may probably be treated as one of highly-ordered smectic mesophases (SH or Sj), whose study is only started74). 

A similar evaluation was made for the other series of CA-g-PHAs to establish a general relationship between their molecular architecture and thermal transition behavior [24]. Of particular interest is the finding that the composition dependence of the Tg of the cellulosic graft copolymers was represented well in terms of a formulation based on a comb-like polymer model [29], when CAs of acetyl DS 2 were employed as a trunk polymer. 

Functionalized comb-like polymers synthesis, modification and application. [H. Ritter, Angew. Makromol. Chem. 1994, 223, 165-175] [ 1777]. 

Revilla, J., Delair, T., Pichot, C. and Gallot, B. (1995) Preparation and properties of comb-like polymers obtained by radical homo- and copolymerization of a liposaccharidic monomer with styrene. Polymer, 37, 687-98. 

Plate N.A. and Shibaev V.P., Comb-Like Polymers and Liquid Crystals, Khimia, Moscow, 1980, p. 303. (Rus)... 

The negative sign of K in polymer solutions of PCEMA, PNOBS and PPhEAA means that the side groups of these comb-like polymers are oriented in the electric field with their long axes normal to the field (in contrast to the corresponding monomer molecules) and, hence, this orientation is not free (as for polystyrene) but is in correlation with that of the main chain. 

Table 9. Relaxation times (ns) for comb-like polymers in polar solvents at 25 °C (rjredO-38 cP) PMA poly(aIkyl methacrylates), n is the number of C-atoms in the alkyl chain...

This review deals with several types of polymer hosts that have been investigated. These include polyethylene oxide and its several modified forms, comb like polymers such as polyacrylates and inorganic polymers such as polyphosphazenes and polysiloxanes. Various instrumental techniques have been employed in the structural characterization of polymer electrolytes. The structural information obtained from methods such as Extended X-ray Absorption Fine Structure (EXAFS), X-ray diffraction methods, vibrational spectroscopy and nuclear magnetic resonance (NMR) have also been discussed. 

Plate, N.A. and Shibaev, V.P., 1980, Grebneobraznye polimeri I zhidkie kristally (Comb-like polymers and liquid crystals), Moscow Khimiya. 

Comb-like polymers with DP 5 were formed in 63% and 83% yields, respectively, inhomopolymerization usingBFj OEt, initiator. Copolymers with 2-phenyl-2-oxazoline were obtained in 65% (Mn = 7,800) and 79% (Mn = 13,700) yields. 

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