Abstraet--Copolymerization of vinyl cyclohexane (monomer-l) with styrene was investigated in the presence of the stereospecific complex catalyst TIC13 q-Al(iso-C4H9)3. Monomer reactivity ratios were rx = 0.177 Β± 0"051 and r2 = 2' 117 Β± 0.370. The monomer unit distributions in the copolymers were estimated by comparison of the i.r.-spectra of copolymers and the isotactic homopolymers using absorption bands at 565 and 1084 cm-x which correspond to the vibrations of styrene blocks containing I> 5 styrene units and the band at 985 cm-1 characterizing polystyrene crystallinity. The data indicate the tendency towards alternation in the copolymerization. Analysis of the experimental and literature data led to the conclusion that distribution of the units in copolymers of vinyl cyclohexane with e-olefins is determined by the nature of the a-olefin. The following activity series is proposed for ct-olefins in their copolymerization with vinyl cyclohexane in the presence of catalytic systems based on titanium salts and organo-aluminium compounds: propylene > 4-methylpentene-I > styrene > 3-methylbutene-I ~ vinyl cyclohexane.
THERE have been reports on copolymerization of the high ~-olefins with styrene (St) using complex organometallic catalysts, t~-4) Reactivity of monomers and distribution of monomer units in the copolymers have been investigated. Homopolymerization of vinyl cyclohexane (VCH) in the presence of complex organometallic catalysts has been studied. (s,6) VCH was copolymerized with various a-olefins. (6-s)
It was of interest to investigate copolymerization of VCH with styrene on organometallic catalysts and to study the copolymer structure. Copolymer composition and structure were studied by i.r.-spectroscopy.
EXPERIMENTAL
Characteristics of the reaction components and the polymer isolation procedure have been described earlier. ~5~ Copolymerization of VCH with St was carried out in the presence of the stereospecific complex catalyst TIC13 + Al(isoC4H9)a, using ampoules under vacuum or dry argon in cyclohexane.
The order of addition of the components to an ampoule was: cyclohexane, St, VCH, TIC13 and ml(isof4n9)3. Molar ratio VCH/St was varied from 10:1 to 1:9, the total comonomer concentration being 2 mole/1. TIC13 concentration was 0"04 mole/l; molar ratio AI/Ti = 3/1. Copolymerization was carried out at 60 Β° for 5-180 rain; conversion was 5-10 wt per cent.
Infra-red spectra of the copolymers, polyvinyl cyclohexane (PVCH) and polystyrene (PS) were recorded with a UR-10 spectrophotometer at 2000-400 cm-~ using thin films (10-20 ~m) prepared by hot moulding at 240 Β° .
Copolymer compositions were determined by means of i.r.-spectroscopy. Band intensities at 1603 or 1494 cm-~ were employed as a measure of St content and the band intensities of CH2 deformation modes at 1451 cm-~ were used for measuring the VCH content (in the copolymers with low VCH content, this band maximum was shifted to 1455 cm-~ owing to its overlap with CH2 absorption of