Intercalation polymerization of allene hydrocarbons in polar and nonpolar media

Abstract

Organomodified layered aluminosilicates and hybrid organic–inorganic nanocomposites based on Na⁺-montmorillonite, Cloisite 20A, and allene hydrocarbons have been obtained under the action of rhodium chloride. The intercalation polymerization includes the cation-exchange reaction, the intercalation of hydrated rhodium chloride (RhCl₃ ∙ 4H₂O) into layered silicates, and the in situ oligomerization of allene or 1,1-dimethylallene. The reaction is performed in polar (Na⁺-montmorillonite) and nonpolar (Cloisite 20A) solvents. Detailed X-ray diffraction studies of the resulting products show that, depending on the reagent concentrations and ratios, oligoallene- and oligo(1,1-dimethylallene)-modified nanofillers with both intercalated and exfoliated morphologies can be obtained. Three independent phases are detected, which suggests the formations of structures with different types of organophilic layers. The structures and properties of polymers and composites obtained by the rhodium chloride-catalyzed polymerization of allene in toluene or a water-ethanol mixture in the presence of aluminosilicates are studied by X-ray diffraction, IR spectroscopy, and differential scanning calorimetry. The polyallenes synthesized in different media are shown to have identical structures (1,2,1,2-addition) and crystallinities (m.p. 124–126°C), but different degrees of aluminosilicate exfoliation in nanocomposites.