Showing papers in "Polymer Degradation and Stability in 1990"

TL;DR: In this article, the thermal degradation of poly(acrylic acid) has been studied using thermal volatilisation analysis (TVA) and thermogravimetry (TG).

TL;DR: In this article, the amounts of volatile liquid and cold ring fraction (CRF) products in the degradation of several anionic and a free radical polystyrene (PS) sample have been determined gravimetrically for degradations under vacuum at 300°C, over the range 5-60% volatilisation.

TL;DR: Silica, alumina, silica-aluminas, and zeolites were screened as catalysts for polystyrene degradation in the range 200-550°C as discussed by the authors.

TL;DR: In this paper, the authors show that carbon volatilisation, on exposure to oxyge, is promoted by the presence of high surface area magnesium oxide formed on decomposition of the parent hydroxide, and that water does not influence CO emission through a water gas reaction.

TL;DR: The thermal degradation of pentaerythritol diphosphate (PEDP) has been extensively studied by means of various thermal analytical techniques as mentioned in this paper, and it is shown that on heating, PEDP degrades in several successive steps with the formation of a complex mixture of volatile products.

TL;DR: A review of degradable plastic technology has revealed that several effective copolymer and additive methods are used commercially for photodegradable plastics as mentioned in this paper, however, it was found that all commercial packaging plastics are not bi-degradable; all of them because their molecular weights are too high and their structures are too rigid for assimilation by organisms, and most of them also because they have substituents which prevent biodegradation via the enzymatic fatty acid oxidation mechanism.

TL;DR: In this paper, the importance of titanium dioxide pigments in reducing the extent of UV and thermal degradation is emphasised, and the durability ranking of pigments is the same as that which has been well established for paints.

TL;DR: In this article, the chemistry underlying these processes is discussed and it is observed that, in the case of the common packaging plastics, methods of inducing degradation range through thermal and biooxidation, photolysis, photo-oxidation and photobiooxidation.

TL;DR: In this article, the regeneration of hindered amine nitroxyls has been investigated with isotopically labeled reactants and the results of this work confirm the new proposed regeneration mechanism but not the previous 'peroxide' mechanism.

TL;DR: In this paper, the authors studied the chemical reactions responsible for the intumescent behavior of pentaerythritol diphosphate (PEDP) and discussed the mechanism of formation of this char.

TL;DR: In this article, the degradation behavior of poly(glycidyl methacrylate) (PGMA) has been studied using thermogravimetry in dynamic nitrogen and thermal volatilisation analysis (TVA) under vacuum, with programmed heating at 10°C/min.

TL;DR: In this paper, the stability of conductive polyaniline has been assessed at elevated temperatures, under high current density and in organic solvents, and X-ray photoelectron spectroscopy results support the postulate that the degradation of protonated polyaniniline is due to the loss of chlorine anions and/or the conversion of some of the anions to covalently bonded chlorine.

TL;DR: In this paper, free radical formation on photolysis of free hydroperoxides in polyethylene is questioned, and other photolyisation mechanisms are proposed instead, leading to the products observed experimentally, i.e. carbonyl and trans-vinylene groups, without intermediate formation of free radicals.

TL;DR: In this paper, the degradation of polyacrylate was studied under programmed heating conditions using thermogravimetry (TG), differential thermal analysis (DTA), and thermal volatilisation analysis (TVA).

TL;DR: In this paper, X-ray photoelectron spectroscopy was used to determine the ionization potentials of polytetrafluoroethylene and polyethylene.

TL;DR: In this paper, non-isothermal thermogravimetry was used for the estimation of volatilization of both water from an inorganic additive (Al(OH) 3 and Mg(OH 2 ) and flammable volatiles from the polymer (polyethylene, EVA copolymer and polypropylene) for composite systems with high contents of the inorganic component.

TL;DR: In this article, it has been shown that Sb 4 O 5 Cl 2 accumulates as a result of these reactions and it becomes the main direct supplier of antimony, as SbCl 3, to the gas phase.

TL;DR: In this article, the effectiveness of hindered amine light stabilizers in reducing carbonyl formation during ultraviolet light exposure of an acrylic melamine coating has been measured by infrared spectroscopy for both a harsh and near-ambient exposure.

TL;DR: In this article, photo-degradation of polyethersulfone (PESF) films was shown to be initiated by cleavage of the CS bond without sulfur dioxide formation.

TL;DR: In this article, substituted maleimides have been investigated as thermal stabilizers for plasticized PVC at 180°C in air by measuring the rate of dehydrochlorination and the extent of discoloration of the degraded polymer.

TL;DR: In this paper, the formation of soot precursors and soot particle inception is described, and the aggregation of particles, surface growth and post-oxidation of the soot is discussed.

TL;DR: In this paper, the photo-oxidation of acrylonitrile-butadiene copolymers (NBR) has been investigated for comparison with the photooxideidation of various polybutadienes (BR), SBR and NBR which have been studied recently.

TL;DR: In this article, the chemistries and rates of photo-oxidation have been studied in a series of acrylic melamine coatings as a function of exposure condition, confirming that the formation of carbonyl species in these coatings is a free radical induced photooxidation process.

TL;DR: In this article, measurements of the evolution of CO and CO2 concentrations during the course of combustion of an EEVA copolymer filled with aluminium trihydroxide (ATH) or magnesium dihydroxides (MDH) confirm the catalytic behaviour of Al2O3 and MgO in the incandescence of the residual char.

TL;DR: In this article, a mechanism for the formation of these coatings is proposed: they form via the decomposition of esters which result either from a reaction between the additives and the products which result from the thermo-oxidative degradation of the polymer.

TL;DR: In this paper, the thermal degradation of polyvinyl chloride (PVC) in trichlorobenzene (TCB) solution at 187°C has been studied in the presence of a 1 1 mixture of zinc and calcium stearates.

TL;DR: In this article, a method of derivation of the kinetic equations for polymer degradation which involves the splitting off of low-molecular weight compounds based on the stochastic approach is suggested.

TL;DR: In this paper, the concentration of nitroxide has been measured in an acrylic melamine coating containing different hindered amine light stabilizers as a function of exposure harshness, time and stabilizer concentration using electron spin resonance spectroscopy.

TL;DR: Combinations of sterically hindered phenolic antioxidants (AO) and hindered piperidine light stabilizers (HALS) are of value as practical stabilizer systems for hydrocarbon polymers as discussed by the authors.

TL;DR: In this paper, the photo-oxidation of EPDM rubber was studied and the mechanism of formation of the oxidation products is similar to that of other unsaturated rubbers, a regeneration of the initiator in the absence of light is observed in contrast to other hydrocarbon polymers.