Relating chemical structure to poly(vinyl chloride) thermal stability

Минскер, К. С.; Lisitsky, V. V.; Zaikov, G.Ye.

doi:10.1002/vnl.730020204

Cited by 16 publications

(2 citation statements)

References 41 publications

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“…Certainly it will give new stimulus in development of scientific bases and practical development with opening of new pathways, conducting to essential delay of PVC's ageing in natural and special conditions at reduction of amounts of the appropriate chemicals -additives, down to their complete elimination. [18][19][20][21][22][23][24][25] …”

Section: ''Echo'' -Stabilization Of Pvcmentioning

confidence: 99%

Effect of Solvent (Plasticizers) on PVC Degradation

Заиков

Artsis

2007

Macromolecular Symposia

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Summary: Both plasticized (semi-rigid and flexible) PVC materials as well as PVC in solutions, the rate of their thermal degradation and effective stabilization are caused by essentially different fundamental phenomena in comparison to aging of PVC in absence of the solvent. Both structure and macromolecular dynamics render the significant influence on its stability, i.e. chemical nature of the solvent (plasticizer), its basicity, specific and non-specific solvation, degree of PVC in a solution (solubility), segmental mobility of macromolecules, thermodynamic properties of the solvent (plasticizer), formation of associates, aggregates, etc. The chemical stabilization of PVC plays a less significant role. The effect of above factors on stability (behavior) of semi-rigid and flexible PVC will be done on quantitative level. It will be described effect of ''echo''-type of stabilization on the stability of PVC in the presence of plasticizers. If we would like to have stable material from PVC we should make stabilization of plasticizers as more reactive chemical compounds.Keywords: aggregates; associates; basicity; plasticizers; segmental mobility of macromolecules; solubility; solution; solvent; specific and non-specific solvation; thermodynamic properties Effect of SolventAt PVC's degradation in solution, one of the basic reasons of change of the process kinetic parameters is the nucleophilic activation of a PVC's dehydrochlorination reaction. The process is described by E 2 mechanism.[1-3] Thus, there is a linear dependence between PVC's thermal dehydrochlorination rate and parameter of solvent's relative basicity B cm À1 (Fig. 1). [1][2][3] (The value B cm À1 is evaluated by shift of a characteristic band OH of phenol at l ¼ 3600 cm À1 in an IR-spectrum at interaction with the solvent [4] ). It is essentially important that the rate of PVC's dehydrochlorination in the solvents with relative basicity B > 50 cm À1 was always above, than the rate of PVC's dehydrochlorination without the solvent, while when B < 50 cm À1 , PVC's desintegration rate was always less, than at it's destruction without the solvent. The revealed dependence V HCl ¼ f (B) is described by the equation:An inhibition of PVC's disintegration in the solvents with basicity B < 50 cm À1 is very interesting and practically important phenomenon. It has received the name ''solvatational'' stabilization of PVC. Let's notice, however, that ignoring of the fact that PVC solutions even at low concentration (2 wt. %) do not represent solutions with isolated macromolecules but rather with structured systems, results that in a number of cases a deviation from linear dependence of PVC dehydrochlorination rate of the solvent basicity B cm À1 is observed. In particular, an abnormal behavior of PVC is observed at destruction in certain ester-type solvents (plasticizers) (Fig. 1, points 25-28), that apparently caused by structural changes of macromo-

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Section: ''Echo'' -Stabilization Of Pvcmentioning

confidence: 99%

Effect of Solvent (Plasticizers) on PVC Degradation

Заиков

Artsis

2007

Macromolecular Symposia

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“…(1) Using this reaction, it is also easy to estimate the content of labile oxovinylene groups in the composition of macromolecules γ 0 from the fall in the viscosity-average molecular weight of PVC (refs. [13][14][15][16][17].…”

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Progress and Tasks of Research in the Area of the Ageing and Stabilisation of Polyvinyl Chloride

Минскер

Заиков

2002

International Polymer Science and Technology

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Translation submitted by P. Curtis Polyvinyl chloride (PVC) is one of the most well-known multitonnage and practically important polymer products. Many thousands of rigid, semisoft, and soft (plasticised) materials and articles, which can be used in virtually all sectors of the national economy and in the home, are based on PVC. It was first produced in 1872 by E. Baumann, but the industrial production of PVC was begun comparatively recently. According to published data, it began in 1935 in Germany, but according to data of the Du Pont company it began in 1930 in the United States. The growth in world production of PVC is impressive: in 1950, 220 000 t was produced; in 1960, in the order of 1.5 million t was produced; in 1965, over 3 million t was produced; in 1970, over 5 million t was produced; at present, PVC production amounts to over 15 million t. The main problem of PVC is its extremely low stability. Under the action of heat, UV light, oxygen, radiations, etc., it breaks down readily by the law of conversion of framing groups, with the elimination of hydrogen chloride and the formation of sequences of double saturated C=C bonds in the macromolecules with the appearance of an undesirable colour (from yellow to black). Therefore, during the storage, processing, and service of PVC, and also during the production, storage, and use of materials and articles based on it, it is necessary to use a combination of methods leading to an increase in the resistance of PVC to different factors, and to its stabilisation.

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The latest achievements in the field of degradation and stabilization of vinyl chloride (CO)polymers

Минскер

1989

Makromolekulare Chemie. Macromolecular Symposia

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The achievements of t h e p a s t years a r e assoc i a t e d , i n t h e f i r s t place, with s o l u t i o n of t h e probl e m s of t h e abnormally low s t a b i l i t y and t h e new ways of e f f e c t i v e s t a b i l i z a t i o n of v i n y l c h l o r i d e (VC) (co)polymers. A generalized approach t o t h e q u a n t i t a t i v e d e s c r i p t i o n of t h e degradation of VC polymers, taking i n t o account t h e short-and long-range e f f e c t s of neighbouring groups, which a r e fundamental f o r t h e chemistry of t h e halogen-containing polymers, has been elaborated. The p r i n c i p a l e f f e c t s of t h e polymer phase s t a t e and t h e solvent n a t u r e on t h e degradation r a t e of VC (co)polymera have been elucidated. This f a c t predetermines d i f f e r e n t approaches t o t h e s t a b i l i z a t i o n of t h e polymer products i n c r e a t i o n of r i g i d and p l a s t icized compositions, including those i n s o l u t i o n s .

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Relating chemical structure to poly(vinyl chloride) thermal stability

Cited by 16 publications

References 41 publications

Effect of Solvent (Plasticizers) on PVC Degradation

Effect of Solvent (Plasticizers) on PVC Degradation

Progress and Tasks of Research in the Area of the Ageing and Stabilisation of Polyvinyl Chloride

The latest achievements in the field of degradation and stabilization of vinyl chloride (CO)polymers

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