Double-strand macromolecule

Double-strand macromolecule consisting of an uninterrupted sequence of rings, with adjacent rings having only one atom in common. 

Note A spiro macromolecule is a double-strand macromolecule with adjacent constitutional units joined to each other through three atoms, two on one side and one on the other side of each constitutional unit. 

Polymer, the macromolecules of which are double-strand macromolecules. 

There is some information in the literature about synthesis of polymers with alternating diorgano-siloxane and organosilsesquioxane units [6-10] in cyclolinear double-stranded macromolecule of the polymer [11], The first series of works has used co-hydrolysis products of dimethyldichloro-silane with phenyltrichlorosilane [6, 7], dimethyldichlorosilane with methyltrichlorosilane [8] or methylphenyldichlorosilane with phenyltrichlorosilane [9] for synthesis of the polymers. 

Using this as a basis, other groups also took up this synthetic method to develop multistep syntheses to conjugated ladder-type polymers (Tour et al., in 1993 Swager et al., in 1994 see Section II.C). This type of synthetic method currently represents the most powerful of the available routes to conjugated, double-stranded macromolecules. 

Lactide/glycoUde polymers have been investigated for delivery of several other macromolecules. Synthetic double-stranded RNA, poly-isosinic acid/polycytidylic acid, a potent inducer of interferon, was formulated in a 53 47 copolymer of DL-lactide-co-glycoUde. The microspheres were evaluated in mice challenged with Right Valley fever virus. More than 16 days protection was afforded versus only 3 days for controls (137). 

In 1993, Scherf and Chmil described the first synthesis of a ladder-type poly(pflra-phenylene-czs-vinylene) (116) [138]. On the one hand, ladder polymer 116 represents, a planar poly(phenylene) containing additional vinylene bridges on the other hand, it is a poly(phenylenevinylene) with aryl-aryl linkages in the polymeric main chain. The target macromolecules, as fully aromatic ladder polymers, are composed of all-carbon six-membered rings in the double-stranded main chain (an example of angularly annelated poly(acene)s). 

Examples of a double-strand polymer are a ladder polymer in which macromolecules consist of an uninterrupted sequence of rings with adjacent rings having two or more atoms in common, and a spiro polymer in which macromolecules consist of an uninterrupted sequence of rings, with adjacent rings having only one atom in common. 

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). 

One can differentiate two main methods for obtaining polymer-polymer complexes 1) formation of complexes from pre-existing chemically and structurally complementary macromolecules 2) polymerization of monomers in the presence of matrix macromolecules introduced in the reaction media. Such matrix polymerization is accompanied by the formation of polymer complexes. In the first case, the chemical reaction proceeds via complex formation by random contacts between reacting chains. Then, these sequences of pairs of connected chains grow. In matrix polymerization, the complex is formed by the mechanism of consecutive addition of monomer along the chain leading to the formation of the so-called zip-up (double-stranded) structure, due to matrix control of polymerization. One can expect that the various mechanisms lead to the formation of complexes with a different structure and properties. Indeed, a difference in the composition and properties of complexes obtained by various methods has been found So, the comparison of complexes poly(methacry-lic acid)-poly(2-N,N-dimethylaminoethyl methacrylate), obtained by mixing of equimolar quantities of components in solution and also by the matrix polymerization of dimethylaminoethyl methacrylate in water in the presence of PMAA, shows a difference in composition. In the first case, the content of acid in the complex is always... 

An alternative approach would generate precursor macromolecules with some disorder of the rigid geometry. A possible way of achieving this is the generation of polymers that have structural units which cause an angular shape of the double-stranded chain. Such precursor polymers then have to be converted into the final ladder macromolecules by means of an elimination or rearrangement step [2, 5]. 

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