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Isotactic polymers of optically active α-olefins
Abstracts
207
below 0°C. This made it possible at --30 ° to obtain the same homogeneous, high molecular polyisoprene ( M ~ 2 × 10e) in the presence of Al(iso-C4Hp)8 as the authors had formerly obtained with the system fl-TiCla--A1Cl(iso-C4Hp)~, b u t at considerably higher rates with the former. *ISOTACTIC POLYMERS OF OPTICALLY ACTIVE :¢-OLEFINS
P . P i n e , D. P . L o r e n z i , L. L a r d i c c i a n d . F . Ciardelli, V y s o k o m o l . s o e d i n . 3: No. 10, 1 5 9 7 - 1 6 0 6 , 1961. THE experimental data obtained by the authors fit in very well with the hypothesis that the isotactic macromolecules of optically active a-olefins assume helical conformations also in the liquid stato or in solution and t h a t the helicized principal chain sections have primarily a single screw sense. The prevalence of conformations of a single screw sense can be attributed in the present case to asymmetric induction b y asymmetric lateral groups, which favour spiralization of the dissolved macromolecules in one of the two possible screw senses. No definite conclusions can be drawn from the data obtained. The fact that even amorphous fractions in the case of poly-(S)-3-methyl-l-pentene and poly-(S)-4-methyl1-hexene have a relatively high optical rotations shows that sequences of few monomeric units are sufficient to afford chain portions which have a well defined helical conformation rather than a randomly coiled conformation and which remarkably contribute to the optical rotation. INFRARED SPECTRA OF POLYMERS WITH CONJUGATED BOND SYSTEMS
N. A. S l o v o k h o t o v a a n d I. V. A s t a f e v , V y s o k o m o l . s o e d i n . 3: No. 10, 1607, 1961. THE infrared spectra of polyvinylene and of its oxidation products have been determined. Oxidation leads to the appearance of bands of OH, CO and C ~ C , conjugated with C ~ ( ) , and to an increase in over-all absorption in the region 1300-1000 cm -1. This bears evidence of the formation of a three-dimensional lattice by means of C--C and C - - O - - C bonds.
207
below 0°C. This made it possible at --30 ° to obtain the same homogeneous, high molecular polyisoprene ( M ~ 2 × 10e) in the presence of Al(iso-C4Hp)8 as the authors had formerly obtained with the system fl-TiCla--A1Cl(iso-C4Hp)~, b u t at considerably higher rates with the former. *ISOTACTIC POLYMERS OF OPTICALLY ACTIVE :¢-OLEFINS
P . P i n e , D. P . L o r e n z i , L. L a r d i c c i a n d . F . Ciardelli, V y s o k o m o l . s o e d i n . 3: No. 10, 1 5 9 7 - 1 6 0 6 , 1961. THE experimental data obtained by the authors fit in very well with the hypothesis that the isotactic macromolecules of optically active a-olefins assume helical conformations also in the liquid stato or in solution and t h a t the helicized principal chain sections have primarily a single screw sense. The prevalence of conformations of a single screw sense can be attributed in the present case to asymmetric induction b y asymmetric lateral groups, which favour spiralization of the dissolved macromolecules in one of the two possible screw senses. No definite conclusions can be drawn from the data obtained. The fact that even amorphous fractions in the case of poly-(S)-3-methyl-l-pentene and poly-(S)-4-methyl1-hexene have a relatively high optical rotations shows that sequences of few monomeric units are sufficient to afford chain portions which have a well defined helical conformation rather than a randomly coiled conformation and which remarkably contribute to the optical rotation. INFRARED SPECTRA OF POLYMERS WITH CONJUGATED BOND SYSTEMS
N. A. S l o v o k h o t o v a a n d I. V. A s t a f e v , V y s o k o m o l . s o e d i n . 3: No. 10, 1607, 1961. THE infrared spectra of polyvinylene and of its oxidation products have been determined. Oxidation leads to the appearance of bands of OH, CO and C ~ C , conjugated with C ~ ( ) , and to an increase in over-all absorption in the region 1300-1000 cm -1. This bears evidence of the formation of a three-dimensional lattice by means of C--C and C - - O - - C bonds.