- Email: [email protected]
Effect of addition agents on the structural viscosity of polymethacrylic acid solutions
Abstracts
949
tric shape. On this basis it was suggested t h a t the mechanical properties (in particular the high strength) of the cord fibers is due to self-reinforcement. I n order to improve the service life of the cord it is desirable to prepare reinforced or self-reinforcement fiber materials. EFFECT OF A D D I T I O N A G E N T S ON T H E S T R U C T U R A L VISCOSITY OF P O L Y M E T H A CRYLIC ACID SOLUTIONS
Ye. A. Kanevskaya, Yu. S. Lipatov and P. I. Zubov, Vysokomo1. soyed. 5: N o . 4, 5 8 7 - 5 9 2 , 1963. THE effect of the addition of alkali and urea on the viscosity of concentrated polymethacrylic acid solutions has been investigated in relation to the temperature and the shearing rate gradient. I t has been shown that the sharp increase in viscosity at the critical shearing rate gradient, due to unfolding of the macromolecules, also occurs in the presence of alkali .and urea additions. This effect, as also the change in sign of the temperature coefficient of viscosity for aqueous solutions of polymethacrylie acid is observed at lower concentrations in the case of addition of alkali and urea than in aqueous solutions without these additions. This is has been related to a change in the ratio between the intra and intermolecular bonds caused by these agents and hence to the change in chain conformation in the solution. CYCLIZATION OF DIENIC POLYMERS -- I. CYCLIZATION OF N A T U R A L R U B B E R IN P H E N O L SOLUTION
I. A. Tutorskii, V. V. Markov, L. P. Fomina, V. B. Belyanin and B. A. Dogadkin, Vysokomol. soyed. 5: No. 4, 593-597, 1963. THE cyclization of natural rubber in phenol medium in the presence of a P205 catalyst has been investigated. The degree of unsaturation of the cyclorubber as determined by the perbenzoic acid reaction is about 25% of the original value. The presence of 275-280 m bands in the ultraviolet spectra of cyclorubber with a peak at 278 m, as well as a number of bands in the I R spectrum at 690 cm-1-740 cm -1 and in the region of 1500-1600 cm -1 indicates the presence of bound phenol in the cyclorubber. S T R U C T U R E OF ACETYLCELLULOSE SOLUTIONS
S. A. Glikman, V. M. Averyanova, L. I. Khomutov, Vysokomol. soyed. 5: N o . 4, 5 9 8 - 6 0 4 , 1963. THE rheological properties of solutions and gels of some unfractionated specimens of partially saponified acetylcellulose (bound acetic acid--54-55~o; intrinsic viscosity--l.4-1.5) have been investigated. After thermostatting for several hours at 60 °, cooled 0.5~o solutions in bcnzyl alcohol and 200/0 solutions in acetone are at first similar in properties to true solutions of polymers. On storage at 20 ° for some days, however, the apparent viscosity of both types of solutions gradually increases, the flow in the case of benzyl alcohol solutions assuming the character of plastic flow, whereas jelly-like clumps appear in the acetone solutions. These effects are reproduced on repeated heating and cooling. The results of the investigation led to the conclusion that at 25 ° both types of solutions are inhomogeneous thixotropic systems differing in the nature of their structures, a continuous gel structure in the case of solution in benzyl alcohol and a discrete structure of j elly-like clumps in acetone.
The Publisher will be pleased to quote for the supply of a full English translation of any paper abstracted in thes9 pages.
949
tric shape. On this basis it was suggested t h a t the mechanical properties (in particular the high strength) of the cord fibers is due to self-reinforcement. I n order to improve the service life of the cord it is desirable to prepare reinforced or self-reinforcement fiber materials. EFFECT OF A D D I T I O N A G E N T S ON T H E S T R U C T U R A L VISCOSITY OF P O L Y M E T H A CRYLIC ACID SOLUTIONS
Ye. A. Kanevskaya, Yu. S. Lipatov and P. I. Zubov, Vysokomo1. soyed. 5: N o . 4, 5 8 7 - 5 9 2 , 1963. THE effect of the addition of alkali and urea on the viscosity of concentrated polymethacrylic acid solutions has been investigated in relation to the temperature and the shearing rate gradient. I t has been shown that the sharp increase in viscosity at the critical shearing rate gradient, due to unfolding of the macromolecules, also occurs in the presence of alkali .and urea additions. This effect, as also the change in sign of the temperature coefficient of viscosity for aqueous solutions of polymethacrylie acid is observed at lower concentrations in the case of addition of alkali and urea than in aqueous solutions without these additions. This is has been related to a change in the ratio between the intra and intermolecular bonds caused by these agents and hence to the change in chain conformation in the solution. CYCLIZATION OF DIENIC POLYMERS -- I. CYCLIZATION OF N A T U R A L R U B B E R IN P H E N O L SOLUTION
I. A. Tutorskii, V. V. Markov, L. P. Fomina, V. B. Belyanin and B. A. Dogadkin, Vysokomol. soyed. 5: No. 4, 593-597, 1963. THE cyclization of natural rubber in phenol medium in the presence of a P205 catalyst has been investigated. The degree of unsaturation of the cyclorubber as determined by the perbenzoic acid reaction is about 25% of the original value. The presence of 275-280 m bands in the ultraviolet spectra of cyclorubber with a peak at 278 m, as well as a number of bands in the I R spectrum at 690 cm-1-740 cm -1 and in the region of 1500-1600 cm -1 indicates the presence of bound phenol in the cyclorubber. S T R U C T U R E OF ACETYLCELLULOSE SOLUTIONS
S. A. Glikman, V. M. Averyanova, L. I. Khomutov, Vysokomol. soyed. 5: N o . 4, 5 9 8 - 6 0 4 , 1963. THE rheological properties of solutions and gels of some unfractionated specimens of partially saponified acetylcellulose (bound acetic acid--54-55~o; intrinsic viscosity--l.4-1.5) have been investigated. After thermostatting for several hours at 60 °, cooled 0.5~o solutions in bcnzyl alcohol and 200/0 solutions in acetone are at first similar in properties to true solutions of polymers. On storage at 20 ° for some days, however, the apparent viscosity of both types of solutions gradually increases, the flow in the case of benzyl alcohol solutions assuming the character of plastic flow, whereas jelly-like clumps appear in the acetone solutions. These effects are reproduced on repeated heating and cooling. The results of the investigation led to the conclusion that at 25 ° both types of solutions are inhomogeneous thixotropic systems differing in the nature of their structures, a continuous gel structure in the case of solution in benzyl alcohol and a discrete structure of j elly-like clumps in acetone.
The Publisher will be pleased to quote for the supply of a full English translation of any paper abstracted in thes9 pages.