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Dimensions of branched macromolecules in good solvents
Abstracts EFFECT OF T H E TYPE PHYSICAL P R O P E R T I E S
OF PLASTICIZATION
939 OF POLYVINYLCE[LORIDE
ON ITS
I. N. R a z i n s k a y a a n d B. P . S h t a r k m a n , V y s o k o m o ] . soyed. 5 : No. 3, 3 9 3 - 3 9 6 , 1963. USING polyvinylchloride plasticized with dioetylphthalate as example, it has been sho~na that depending upon the method of incorporating the plasticizer (simple heating or mastication with breakdown of the supermolecular structure) one can obtain materials of identical chemical composition b u t different physical properties (strength, ultimate elongation, glass transition point a n d temperature dependence of the melt viscosity). The results have been explained in terms of inter-bundle and intra-bundle plasticization. DIMENSIONS OF B R A N C H E D MACROMOLECULES IN GOOD SOLVENTS
A. K . K r o n a n d O. B. P t i t s y n , V y s o k o m o l . s o y e d . 5 : No. 3, 3 9 7 - 4 0 4 , 1963.
EQUATIONS derived in the present work for the volume effects in branched macromolecules with one, two a n d three points of branching show these effects to have a greater influence on the dimensions of the branched t h a n of analogous linear chains. The ratio of branched chain to linear chain dimensions in good solvents for equal molecular weights tends to a constant value with increase in the number of branches (in a 0-solvent, as is well known this ratio tends to zero). I t thus follows that the dimensions of molecules in good solvents are much less sensitive to branching t h a n are their dimensions in 0-solvent. The second virial coefficient of a branched macromolecular solution is less than in the case of the corresponding linear molecules; however the difference is not very great. N U C L E A R MAGNETIC R E S O N A N C E S T U D I E S OF P O L Y M E R S - - H I . P O L Y H A L O G E N O S T Y R E N E MACROMOLECULES
MOBILITIES O F
R. A. A b d r a s h i t o v , N. M. B a z h e n o v , M. V. V o l k e n s h t e i n , A. I. K o l ' t s o v a n d A. S. K h a c h a t u r o v , V y s o k o m o l . s o y e d . 5 : No. 3, 4 0 5 - 4 1 1 , 1963. TEMPERATURE dependencies of the second moments for the NMR-absorption lines of fluorine a n d hydrogen nuclei in poly-2-fluoro-5-methylstyrene have been determined. From a comparison of the values calculated theoretically and obtained experimentally it has been concluded that these polymers possess a planar syndiotactic structure, the radicals of which, on raising the temperature to 85 °, begin syn-phase rotating oscillations of a cooperative character. STATISTICAL T H E O R Y OF V O L U M E EFFECTS IN MACROMOLECULES
A. K . K r o n a n d 0 . B. P t i t s y n , V y s o k o m o ] . s o y e d . 5 : No. 3, 4 1 2 - 4 1 6 , 1963. A GENERAL statistical method has been proposed for investigating volume effects in polymer chains, in which the free energy" of the macromolecules is expressed through the probability of segment collision in a partially "discharged" chain. An approximate expression for the expansion coefficient a of the chain has been derived on the basis of calculation of the collision probability for an effective gaussian chain. I t h a s been shown that with this approximation u2~ M0.24 (for a >>1/, whereas according to Flory's theory a 2 ~ M °'2°. The Publisher will be pleased to quote for the supply of a full English translation of a n y papers abstracted in these pages.
OF PLASTICIZATION
939 OF POLYVINYLCE[LORIDE
ON ITS
I. N. R a z i n s k a y a a n d B. P . S h t a r k m a n , V y s o k o m o ] . soyed. 5 : No. 3, 3 9 3 - 3 9 6 , 1963. USING polyvinylchloride plasticized with dioetylphthalate as example, it has been sho~na that depending upon the method of incorporating the plasticizer (simple heating or mastication with breakdown of the supermolecular structure) one can obtain materials of identical chemical composition b u t different physical properties (strength, ultimate elongation, glass transition point a n d temperature dependence of the melt viscosity). The results have been explained in terms of inter-bundle and intra-bundle plasticization. DIMENSIONS OF B R A N C H E D MACROMOLECULES IN GOOD SOLVENTS
A. K . K r o n a n d O. B. P t i t s y n , V y s o k o m o l . s o y e d . 5 : No. 3, 3 9 7 - 4 0 4 , 1963.
EQUATIONS derived in the present work for the volume effects in branched macromolecules with one, two a n d three points of branching show these effects to have a greater influence on the dimensions of the branched t h a n of analogous linear chains. The ratio of branched chain to linear chain dimensions in good solvents for equal molecular weights tends to a constant value with increase in the number of branches (in a 0-solvent, as is well known this ratio tends to zero). I t thus follows that the dimensions of molecules in good solvents are much less sensitive to branching t h a n are their dimensions in 0-solvent. The second virial coefficient of a branched macromolecular solution is less than in the case of the corresponding linear molecules; however the difference is not very great. N U C L E A R MAGNETIC R E S O N A N C E S T U D I E S OF P O L Y M E R S - - H I . P O L Y H A L O G E N O S T Y R E N E MACROMOLECULES
MOBILITIES O F
R. A. A b d r a s h i t o v , N. M. B a z h e n o v , M. V. V o l k e n s h t e i n , A. I. K o l ' t s o v a n d A. S. K h a c h a t u r o v , V y s o k o m o l . s o y e d . 5 : No. 3, 4 0 5 - 4 1 1 , 1963. TEMPERATURE dependencies of the second moments for the NMR-absorption lines of fluorine a n d hydrogen nuclei in poly-2-fluoro-5-methylstyrene have been determined. From a comparison of the values calculated theoretically and obtained experimentally it has been concluded that these polymers possess a planar syndiotactic structure, the radicals of which, on raising the temperature to 85 °, begin syn-phase rotating oscillations of a cooperative character. STATISTICAL T H E O R Y OF V O L U M E EFFECTS IN MACROMOLECULES
A. K . K r o n a n d 0 . B. P t i t s y n , V y s o k o m o ] . s o y e d . 5 : No. 3, 4 1 2 - 4 1 6 , 1963. A GENERAL statistical method has been proposed for investigating volume effects in polymer chains, in which the free energy" of the macromolecules is expressed through the probability of segment collision in a partially "discharged" chain. An approximate expression for the expansion coefficient a of the chain has been derived on the basis of calculation of the collision probability for an effective gaussian chain. I t h a s been shown that with this approximation u2~ M0.24 (for a >>1/, whereas according to Flory's theory a 2 ~ M °'2°. The Publisher will be pleased to quote for the supply of a full English translation of a n y papers abstracted in these pages.