The interaction of triphenylmethyl salts with α‐methylstyrene and 1,1‐diphenylethylene was investigated. With 1,1‐diphenylethylene at a monomer‐initiator ratio of 2 (room temperature), mainly 1,1,3‐triphenyl‐3‐methyl‐indane was isolated, whereas at a ratio of 100 (−10°C), the dimer 1,1,3,3‐tetraphenylbutene‐1 mainly formed. In both cases no addition of the trityl group was registered. In the interaction of α‐methylstyrene with Ph3C+SbCl 6− at a monomer‐initiator ratio of 2(room temperature) a pure 1,3,3‐trimethyl‐1‐phenylindane was isolated and no addition of the trityl group to the double bond was recorded. The initiation reaction of α‐methylstyrene polymerization by trityl and chlorinated trityl salts was studied at temperatures from −20 to 0°C and different concentrations. The oligomers obtained with (pCI‐C6H4)3C+ were investigated by elemental analysis and fluorescence spectroscopy. The presence of Ph3CH in the reaction mixture was demonstrated by GLC and NMR spectra. The results obtained give evidence that the initiation of α‐methylstyrene polymerization involves hydride abstraction from the monomer.
For cationic copolymerization of styrene and p-substituted styrenes the experimental aim values, ratio of monomer reactivity ratios (log(rl/rz)) and average degrees of polymerization (log p), can be connected by linear multiparameter equations with parameters characterizing the influence of monomer structure (Au,), solvent (ET), the reaction temperature (T) and the catalyst activity (xkaI.; E G ,~+~~. ) . The equations allow qualitative and partially quantitative predictions for the selectivity of the cross-propagation reaction in the copolymerization (log(rl/rz)).
Einleitung
Nylon 6–PIB diblock, triblock, and tristar radial block copolymers have been synthesized from telechelic hydroxyl‐terminated polyisobutylene, PIB(OH)n (n = 1,2,3), by conversion of this prepolymer with hexamethylene diisocyanate (HMDI), toluene diisocyanate (TDI), N‐chlorocarbonyl diisocyanate (NCCI), and oxalyl chloride (OxCl) and using the resulting materials as macroactivators for anionic caprolactam polymerization. Prepolymers with molecular weights from 6000 to 38,000 have been employed. Derivatization with NCCI and subsequent anionic caprolactam polymerization gave highest yields and blocking efficiencies. The block copolymers have been characterized by molecular weight and composition. In addition to the expected Tg and Tm characteristics of long PIB and nylon 6 segments, DSC studies showed an intermediate glass transition at ca. −20°C. Transmission electron microscopy of di‐, tri‐, and radial blocks show increasing segregation and orientation of rubbery/crystalline domains. Tensile strengths and elongations of the block copolymers range from 16.5 to 41 MPa and 15 to 30%, respectively, and stress‐strain diagrams show the effect of block architecture on these properties.
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