ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Atomic and molecular dispersions of inorganic solids in monomer media has been found capable of giving rise to highly active polymerization centers effective at low tempera- tures It was shown, using BeCl ZnClz, LiC1, TiC1, and RloOj, that salts and oxides which in the form of perfect crystals are not polymerization catalysts, in the molecular disperse state or with highly defective structures may cause the polymerization of a number of monomers (styrene, a-methylstyrene, isoprene) at their melting points. A study was made of the initiating capacity of some metals in molecular mixtures with monomers. It was shown that with suchamixtures of Mg and acrylonitrile, methyl methacrylate, or methyl acrylate rapid low-temperature polymerization in the solid state takes place. The polymerization is induced by radicals formed on reaction of Mg with the monomers. Similar conversions may occur in the presence of other metals (Hg, Zn, Cd). The methyl methacrylate produced in this way was found to have an isotactic structure. Hence the part played by preliminary ordering of the monomer on the formation of the polymer microstructure has been demonstrated. Studies with the crystalline salts of acrylic and methacrylic acids show that it is possible to initiate poly- merization in the solid phase by the formation of defective crystal structures in the system. This may be arcomplished by heterogeneous chemical reactions and intensive mechanical dispersion of the solid monomers.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1961.1205215711
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