Kinetic study of thermal dehydrochlorination of poly(vinyl chloride) in the presence of oxygen

Valko, L.; Klein, Erik; Kovařı́k, Pavel; Bleha, Tomáš; Šimon, Peter

doi:10.1016/s0014-3057(00)00239-1

Cited by 44 publications

(26 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, it gives a clear picture about the surface irregularity, defects and the crystalline case [32]. In addition, it allows monitoring the changes within the surface of the polymeric material as a result of photodecomposition or stabilization of polymers when exposed to ultraviolet radiation in which decomposition process can occur as chain scission [33]. The surface morphology images of the non-irradiated PVC films in the presence and absence of Schiff's base additives are shown in Figure 7.…”

Section: Surface Morphology For Poly(vinyl Chloride) Filmsmentioning

confidence: 99%

Viscoelastic, Spectroscopic and Microscopic Study of the Photo Irradiation Effect on the Stability of PVC in the Presence of Sulfamethoxazole Schiff’s Bases

et al. 2015

View full text Add to dashboard Cite

Abstract:The photostabilization of poly(vinyl chloride) (PVC) films having five Schiff's bases derived from sulphamethoxazole has been investigated. The casting method was used to produce PVC films containing sulphamethoxazoles (0.5% by weight), in tetrahydrofuran. The photostabilization activities of five additives were determined by monitoring the hydroxyl, polyene and carbonyl indices with irradiation time. In addition, the quantum yield of the chain scission (Φcs) and the changes in viscosity average molecular weight of PVC films containing Schiff's basses were evaluated with irradiation time. The rate of photostabilization for PVC films in the presence of five Schiff's base additives was found to be the highest in the case of 2-hydroxybenzylidene derivative and the lowest in the unsubstituted benzylidene derivative. Several mechanisms have been suggested to explain the photostabilization of PVC in the presence of Schiff's bases that mainly act as UV absorbers and radical scavengers for photostabilizers.

show abstract

Section: Surface Morphology For Poly(vinyl Chloride) Filmsmentioning

confidence: 99%

Viscoelastic, Spectroscopic and Microscopic Study of the Photo Irradiation Effect on the Stability of PVC in the Presence of Sulfamethoxazole Schiff’s Bases

et al. 2015

View full text Add to dashboard Cite

show abstract

“…A wide variety of synthetic and naturally occurring high polymers absorb solar ultraviolet radiation and undergo photolytic, photooxidative, and thermooxidative reactions that result in the degradation of the material (Ayako and Hirose 1999; Scott 2000; Valkoa et al 2001). …”

Section: Introductionmentioning

confidence: 99%

Photodegradation and photostabilization of polymers, especially polystyrene: review

2013

View full text Add to dashboard Cite

Exposure to ultraviolet (UV) radiation may cause the significant degradation of many materials. UV radiation causes photooxidative degradation which results in breaking of the polymer chains, produces free radical and reduces the molecular weight, causing deterioration of mechanical properties and leading to useless materials, after an unpredictable time. Polystyrene (PS), one of the most important material in the modern plastic industry, has been used all over the world, due to its excellent physical properties and low-cost. When polystyrene is subjected to UV irradiation in the presence of air, it undergoes a rapid yellowing and a gradual embrittlement. The mechanism of PS photolysis in the solid state (film) depends on the mobility of free radicals in the polymer matrix and their bimolecular recombination. Free hydrogen radicals diffuse very easily through the polymer matrix and combine in pairs or abstract hydrogen atoms from polymer molecule. Phenyl radical has limited mobility. They may abstract hydrogen from the near surrounding or combine with a polymer radical or with hydrogen radicals. Almost all synthetic polymers require stabilization against adverse environmental effects. It is necessary to find a means to reduce or prevent damage induced by environmental components such as heat, light or oxygen. The photostabilization of polymers may be achieved in many ways. The following stabilizing systems have been developed, which depend on the action of stabilizer: (1) light screeners, (2) UV absorbers, (3) excited-state quenchers, (4) peroxide decomposers, and (5) free radical scavengers; of these, it is generally believed that excited-state quenchers, peroxide decomposers, and free radical scavengers are the most effective. Research into degradation and ageing of polymers is extremely intensive and new materials are being synthesized with a pre-programmed lifetime. New stabilizers are becoming commercially available although their modes of action are sometimes not thoroughly elucidated. They target the many possible ways of polymer degradation: thermolysis, thermooxidation, photolysis, photooxidation, radiolysis etc. With the goal to increase lifetime of a particular polymeric material, two aspects of degradation are of particular importance: Storage conditions, and Addition of appropriate stabilizers. A profound knowledge of degradation mechanisms is needed to achieve the goal.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-398) contains supplementary material, which is available to authorized users.

show abstract

“…. ), molecular oxygen in ground or excited (singlet) state, other oxidants [3][4][5] or biotic factors [6][7][8]. These factors cause both the statistical cleavage and depolymerization of cellulose, hemicelluloses and lignin macromolecules.…”

Section: Introductionmentioning

confidence: 99%

The application of FTIR spectroscopy on characterization of paper samples, modified by Bookkeeper process

Polovka

Polovková

Vizárová

et al. 2006

Vibrational Spectroscopy

View full text Add to dashboard Cite

Kinetic study of thermal dehydrochlorination of poly(vinyl chloride) in the presence of oxygen

Cited by 44 publications

References 35 publications

Viscoelastic, Spectroscopic and Microscopic Study of the Photo Irradiation Effect on the Stability of PVC in the Presence of Sulfamethoxazole Schiff’s Bases

Viscoelastic, Spectroscopic and Microscopic Study of the Photo Irradiation Effect on the Stability of PVC in the Presence of Sulfamethoxazole Schiff’s Bases

Photodegradation and photostabilization of polymers, especially polystyrene: review

The application of FTIR spectroscopy on characterization of paper samples, modified by Bookkeeper process

Contact Info

Product

Resources

About