Polymeric amorphous

There are also various other forms of sulfur including cyclohexa-fSe), cyclo-hepta-fSv), cyclonona-fSg), cyclodeca-(Sio) and cyclododecafSig) sulfur. Polymeric amorphous sulfur of molecular weight about 200,000 also is known. 

Kovacs, A. J. Transition vitreuse dans les polymeres amorphes. Etude phenomeno-logique. Vol. 3, pp. 394—507. 

Cyanide bonds to platinum(II) via the carbon atom. The nitrogen atom of the coordinated cyanide ligand reacts with electrophiles forming adducts. Along with examples in Section 52.3, the complex Pt(CN)2- reacts in a similar manner with (jj-Cp)2ZrI2 and (jj5-Cp)2HfI2 in solution to yield polymeric amorphous solids of type [( ) 5-Cp)2ZrPt(CN)4] .274... 

There are two principal synthetic routes to dicarboxylate complexes. One of these uses an aqueous solution of the alkali metal dicarboxylate and the corresponding metal halide,93 while the other depends upon the dicarboxylic acid reduction of higher oxidation state metals. This reductive property of oxalic acid results in its ready dissolution of iron oxides and hence a cleaning utility in nuclear power plants.94 Mention must also be made of the successful ligand exchange synthesis of molybdenum dicarboxylates, Mo(dicarboxylate)2 H2 O, from the corresponding acetate complex. Unfortunately the polymeric, amorphous and insoluble nature of these complexes has restricted the study of these systems, which may well provide examples of multiple M—M bonding in dicarboxylate coordination chemistry.95... 

Perez J, Physique et Mecanique des Polymeres Amorphes, Lavoisier, Paris, 1992. 

Due to the lack of vinyl monomers giving rise to crystalline segment by cationic polymerization, amorphous/crystalline block copolymers have not been prepared by living cationic sequential block copolymerization. Although site-transformation has been utilized extensively for the synthesis of block copolymers, only a few PIB/crystalline block copolymers such as poly(L-lactide-fc-IB-fc-L-lactide) [92], poly(IB-fr- -caprolactone( -CL)) [93] diblock and poly( -CL-fr-IB-fr- -CL) [94] triblock copolymers with relatively short PIB block segment (Mn< 10,000 g/mol) were reported. This is most likely due to difficulties in quantitative end-functionalization of high molecular weight PIB. 

Thus obtained results show that the polyamorphic transitions occur not only at compression (Si02, H20, etc.) but at extension as well (C) in the systems having stable or metastable crystal analogs with a different density and a different coordination number z. At the minimal z=2 (chain structures) the transitions may occurs only at compression, at the maximal z=12 (close-packed structures) - only at extension, at the intermediate z (2structure-sensitive properties change and new metastable phases can appear. Amorphization under radiation (crystal lattice extension) can be associated with a softening of phonon frequencies. The transitions in the molecular glasses consisted from the molecules with unsaturated bonds are accompanied by creation of atomic or polymeric amorphous systems. 

Transition vitreuse dans les polymeres amorphes. Etude phenomenologique 411... 

Des dtudes analogues faisant appel aux experiences de fiuage et de relaxation montrent (Kurkjlan, 1962 De Bast et Gilard, 1962), que pour des verres mineraux cette distribution est beaucoup moins etendue que celle des polymeres amorphes. II en est de meme avec des verres organiques simples. On peut en conclure que le rearrangement des con-... 

Transition vitreuse dans Ies polymeres amorphes. Etude phenomdnologique 483... 

Osawa and Doi (1992) described a surface layer of plasma-polymerized amorphous C over the transport layer to retard ozone interactions with the transport material along with increased transport material at the interface to compensate for any material that may be destroyed. The reasoning is that without a protective surface layer, the transport layer is destroyed by ozone but the surface is continually abraded so the cycling characteristics are relatively unaffected. However, in an overcoated photoreceptor the surface layer cannot be worn away and destruction of transport material by ozone results in a rising residual potential with cycling. This effect can be reduced by having a higher concentration of transport material at the interface. 

Kovacs, a. Transition Vitreuse dans le Polymeres Amorphes. Etude Pheno-raenologique. Advan, Polymer Sci. 3, 394—507 (1963). 

Bernes, A., Etude de la metastabilite d un polymere amorphe (polystyrene atactique) en fonction de son histoire thermodynamique par spectroscopie enthalpique dielectrique, Ph.D. thesis, Toulouse University, France, 1985. 

---