Macromolecules polymethylenic

Sung C.S.P. and Schneider N.S., Infrared studies of hydrogen bonding in toluene diisocyanate based polymethylene, Macromolecules, 8, 68, 1975. 

Table 20 presents the results pertaining to the synthesis and properties of the gels. The gels are seen to sorb heparin from plasma solution. Their capacity (the maximal amount of heparin sorbed) increases as the mobility and accessibility of the cholesterol fragment for the macromolecules of heparin is increased by varying the length of the polymethylene spacer. The data in Table 20 illustrate that the capacity varies from 0.7 to 0.9 and 1.3 mg/mg of immobilized UChD for cholesterol esters of N-meth-acryloyl-fS-alanine (n — 2), N-acryloyl-co-aminoenantic acid (n = 6), and N-meth-acryloyl-co-aminolauric acid (n = 11), respectively. 

Thus, the remoteness of mesogenic groups from the backbone provided by a polymethylene spacer secures them sufficient autonomy from the main chain. On the other hand, the fact that mesogenic groups are chemically linked with the main chain of the macromolecule assists their cooperative interaction. This is why comblike polymers have come to be accepted as convenient matrices for constructing LC polymers. Already a few hundred liquid-crystalline polymers with various mesogenic side groups have been synthesized. 

R. H. Boyd, Macromolecules, 22, 2477 (1989). An Off-Lattice Constant-Pressure Simulation of Liquid Polymethylene. 

Ia2a. Sensitized photopolymerization of N,N -alkylenebisdichloromaleimides. The photodimerization of maleic anhydride, raaleimide and derivatives has been studied by several research groups (170-172). The benzophenone-sensitlzed photoreaction of N,N -alkylenebisdichloromaleimides [95] with a long polymethylene chain between the two chromophores resulted in the formation of macromolecules (173). The data are collected in Table 12. 

For some time, we have been interested in designing selective chemical modification reactions for coal with a particular emphasis upon characterizing the carbon skeleton of coal (2). The strategy for the approach starts with the working hypothesis that coal can be viewed as a three-dimensional macromolecule in which aromatic and hydroaromatic clusters are cross-linked to one another by various functional groups such as methylene units and polymethylene chains. In addition, the aromatic and hydroaromatic clusters, at least in bituminous coals, are assumed to be derived from polynuclear aromatic compounds (3, 4). 

Staudinger s historical merits for our knowledge of diazoalkanes, based on his work between 1911 and 1921, became somewhat overshadowed by his later and clearly more fundamental and pioneering ideas about the formation and structure of macromolecules (Nobel Prize 1953). It should be emphasized, however, that his development of the concept of polymerization was, at least in part, based on his observations of the formation of polymethylene in the dediazoniation of diazomethane. Macromolecular chemistry, therefore, appears to be a child of early diazo chemistry ... 

Yoon, D. Y, and Bruckner, S., Configurational characteristics of thermotropic polymers comprising rigid groups connected by polymethylene spacers. Macromolecules, 18, 651-657... 

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