- Email: [email protected]
Anionic polymerization of formaldehyde
i 98
Abstracts
fragility in the glass state to a greater extent than in the case of plasticizers soluble in cellulose triacetate. The most probable cause of this effect lies in the lower packing density of the secondary structures (packets) in the films containing the limitedly compatible plasticizer.
I N V E S T I G A T I O N OF P O L Y M E R S S U B J E C T E D TO U N I - A X I A L STRETCH A T H I G H D E F O R M A T I O N VELOCITIES
A. I. M a k l a k o v , G. G. P i m e n o v , a n d R . Y a . S a g i t o v , V y s o k o m o l . s o e d i n . 3: No. 9, 1 4 1 0 - 1 4 1 4 , 1961. IT has been found with the aid of X-ray analysis that the formation of a silver neck during forced deformation of amorphous polyethyleneterephthalate carried out at room temperature is accompanied by phase transition. The phenomenon of the "silverings" of specimens on uniaxial deformation at high rates is also observed for a n u m b e r of crystaline polymers. I n this case, however, no phase transition is observed. The conditions for the formation of "silvers" in polyethyleneterephthalate have been investigated and some of its properties have been studied.
* G R A F T P O L Y M E R S A N D C O P O L Y M E R S - - X X X V . G R A F T COPOLYMERS F R O M COP O L Y M E R OF S T Y R E N E W I T H MALEIC A N H Y D R I D E A N D P O L Y H Y D R O X Y P E L A R GONATE
T s e n K h a n - m i n a n d H . S. K o l e s n i k o v , V y s o k o m o l . s o e d i n . 3: No. 9, 1 4 1 5 - 1 4 2 0 , 1961. G~tAFT copolymers have been prepared by interaction of copolymer of styrene and maleic anhydride with-eo-hydroxypelargonic acid or polyhydroxypelargonate and their properties have been investigated. Highly ordered graft copolymers have been found to form spherulites.
ANIONIC P O L Y M E R I Z A T I O N OF F O R M A L D E H Y D E
A. M a c h £ S e k , J . M e j z l i k a n d J . Pho, V y s o k o m o l . s o e d i n . 3: No. 9, 1 4 2 1 - 1 4 2 6 , 1961. IN order to study the kinetics of formaldehydepolymerization the authors have developed a dilatometric technique, permitting determination of reaction rates at --60 °. The polymer precipitates from the reaction mixture and after its isolation the molecular weight is determined viscometrically. A linear relationship has been found to exist between the amount of polymer formed and the volume contraction. The reaction curves reveal a higher than second reaction order with respect to the monomer. As polymerization catalyst dibutylamine has been used in concentrations ranging from 10-e to 105mole/1. At a monomer concentration of approximately 5mole/1. a n approximately linear relation exists between the dibutylamine concentration and polymerization rate, a small part of the catalyst being consumed through reaction with a strong acid present as an impurity. The molecular weight falls only slightly with increasing dibutylamine concentration. Water, an impurity normally present in formaldehyde, was intentionally added to the polymerizing system (in concentrations up to 100 millimole/1). I t has been found to affect very little the reaction rate, b u t to lower the molecular weight of the polymer.
Abstracts
fragility in the glass state to a greater extent than in the case of plasticizers soluble in cellulose triacetate. The most probable cause of this effect lies in the lower packing density of the secondary structures (packets) in the films containing the limitedly compatible plasticizer.
I N V E S T I G A T I O N OF P O L Y M E R S S U B J E C T E D TO U N I - A X I A L STRETCH A T H I G H D E F O R M A T I O N VELOCITIES
A. I. M a k l a k o v , G. G. P i m e n o v , a n d R . Y a . S a g i t o v , V y s o k o m o l . s o e d i n . 3: No. 9, 1 4 1 0 - 1 4 1 4 , 1961. IT has been found with the aid of X-ray analysis that the formation of a silver neck during forced deformation of amorphous polyethyleneterephthalate carried out at room temperature is accompanied by phase transition. The phenomenon of the "silverings" of specimens on uniaxial deformation at high rates is also observed for a n u m b e r of crystaline polymers. I n this case, however, no phase transition is observed. The conditions for the formation of "silvers" in polyethyleneterephthalate have been investigated and some of its properties have been studied.
* G R A F T P O L Y M E R S A N D C O P O L Y M E R S - - X X X V . G R A F T COPOLYMERS F R O M COP O L Y M E R OF S T Y R E N E W I T H MALEIC A N H Y D R I D E A N D P O L Y H Y D R O X Y P E L A R GONATE
T s e n K h a n - m i n a n d H . S. K o l e s n i k o v , V y s o k o m o l . s o e d i n . 3: No. 9, 1 4 1 5 - 1 4 2 0 , 1961. G~tAFT copolymers have been prepared by interaction of copolymer of styrene and maleic anhydride with-eo-hydroxypelargonic acid or polyhydroxypelargonate and their properties have been investigated. Highly ordered graft copolymers have been found to form spherulites.
ANIONIC P O L Y M E R I Z A T I O N OF F O R M A L D E H Y D E
A. M a c h £ S e k , J . M e j z l i k a n d J . Pho, V y s o k o m o l . s o e d i n . 3: No. 9, 1 4 2 1 - 1 4 2 6 , 1961. IN order to study the kinetics of formaldehydepolymerization the authors have developed a dilatometric technique, permitting determination of reaction rates at --60 °. The polymer precipitates from the reaction mixture and after its isolation the molecular weight is determined viscometrically. A linear relationship has been found to exist between the amount of polymer formed and the volume contraction. The reaction curves reveal a higher than second reaction order with respect to the monomer. As polymerization catalyst dibutylamine has been used in concentrations ranging from 10-e to 105mole/1. At a monomer concentration of approximately 5mole/1. a n approximately linear relation exists between the dibutylamine concentration and polymerization rate, a small part of the catalyst being consumed through reaction with a strong acid present as an impurity. The molecular weight falls only slightly with increasing dibutylamine concentration. Water, an impurity normally present in formaldehyde, was intentionally added to the polymerizing system (in concentrations up to 100 millimole/1). I t has been found to affect very little the reaction rate, b u t to lower the molecular weight of the polymer.