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Digitale Medien

Reatarding effect of nitrogen ylide for the polymerization of N-vinyl pyrrolidone (1990)

Vasishtha, R. ; Kumar, P. ; Awasthi, S. K. ; [weitere]

Springer

Colloid & polymer science 268 (1990), S. 645-648

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ISSN: 1435-1536

Schlagwort(e): β-picolinium-p-chlorophenacylide ; α-α azobisisobutyronitrile ; N-vinyl pyrrolidone ; dilatometry ; retarder ; kinetics

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Maschinenbau

Notizen: Abstract β-Picolinium-p-chlorophenacylide (β-PCFY) acts as a retarder for polymerization of N-vinyl pyrrolidone. The polymerization runs were carried out at 60°C using benzene as an inert solvent. The kinetic equation for the present system may be written asR p α[β-PCPY]−1.0 [AIBN]0.66[N-VP]1.0. The value of overall energy of activation for polymerization in presence and absence ofβ-PCPY was computed as 44.0 and 42.3 kJ mol−1, respectively. The inverse relationship ofR p and¯M v withβ-PCPY suggests thatβ-PCPY acts as a polymerization retarder. The retarding effect is also evidenced by higher initiator exponent value and higher value of energy of activation in presence of ylide. A mechanism is also proposed in which polymer propagating chain combines with one ylide component to give resonance stabilized radical.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01410406

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Digitale Medien

Copolymerization of zinc acrylate with acrylonitrile initiated by As2S3-styrene complex (1994)

Agrawal, B. P. ; Srivastava, A. K.

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 34 (1994), S. 105-109

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ISSN: 0959-8103

Schlagwort(e): Zinc acrylate ; acrylonitrile ; As2S3-styrene complex ; copolymerization ; dilatometry ; kinetics ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Radical copolymerization of zinc acrylate (ZnA2) with acrylonitrile (AN), initiated by As2S3-styrene complex(I), in dimethyl Sulphoxide (DMSO) at 90 ± 0.1°C for 1.0h under inert atmosphere, yields non-alternating copolymers. The kinetic expression is Rp ∝ [I]0.33 [ZnA2]0.25 [AN]0.44, i.e. the system follows non-ideal kinetics, which is due to primary radical termination as well as degradative chain transfer reactions. The values for activation energy (E) and k2p/kt are 128kJ mol-1 and 8.57 × 10-7 litre mol-1 s-1, respectively. Thermal stability, solubility in different solvents, and IR and NMR spectra have been evaluated.

Zusätzliches Material: 5 Ill.