Poly halogen Interactions

Interaction of Halogens with Single Crystals of Poly( 1,6-di-A -carbazolyl-2,4-hexadiyne)... 

Polyacetylene reacts with chlorine rapidly to give a white polymer that is equivalent to poly(l,2-dichloroethylene) and no stereospecificity has been reported on the chlorinated polymer. The addition of halogens is an important general reaction of carbon-carbon double bonds in a stereospecific and regiospecific sense. For instance, the electrophilic additions of chlorine to ethylene, buta-1,3-diene and hexa-l,3,5-triene have been shown to proceed by 1,2-trans (anti), 1,4-cis (syn) and 1,6-trans (anti) attack, respectively. This stereospecificity has been rationalized with a mixing rule of a-n orbital interaction. The reaction of a long conjugated polyene like polyacetylene with chlorine may produce an atactic chlorinated polyene, because random l,2n additions occur to result in a random addition product. ... 

Energy parameters and charge-transfer spectra of complexes of Br2 with several substituted pyridines have now been compared with the force constants k(Br—Br) and k(N- Br2) and with the properties of the donors. The complexes with orr/to-substituted pyridines show systematic deviations from the relations found to be valid for the other donors. The n.m.r. spectrum of the pyridine-Br2 complex in a nematic phase has been obtained and analysed. The results indicate that the donor-acceptor interaction is similar to that found in the solid state for other halogen-pyridine complexes. The equilibrium constant for the formation of the 1 1 complex of Br2 with hexamethyl-phosphortriamide (HMPA) has been determined by n.m.r. spectroscopy. Solid adducts of Br2 with poly-HMPA could also be prepared. 

It had been known that PMMA was compatible with PVC under some conditions, but contrary to earlier reports it has recently been found that a wide range of polyacrylates and polymethacrylates show compatibility with PVC. Such polymers are believed to be compatible due to a specific interaction between the carbonyl group in the ester and the hydrogen or halogen in the PVC. Similarly, it was known that poly(vinylidene fluoride) was compatible with PMMA and poly(ethyl methacrylate), it has now also been shown to be compatible with poly(vlnyl acetate), poly(vinyl methyl ketone), and polyacrylates. This work has also been extended to show the effect of tacticity on the compatibility of poly(ethyl methacrylate) where ail isomers are compatible but the isotactic form phase separates on heating."... 

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