Showing papers in "Polymer Degradation and Stability in 1985"

TL;DR: The thermal degradation of polylactide has been studied at several temperatures in the range 230-440°C and the variation of product distribution with temperature has been examined as discussed by the authors.

TL;DR: The effect of time of polymerization on molecular weight and stability has been examined in this paper, and the effect of polylactide decomposition to oligomers has been investigated.

TL;DR: On heating, ammonium polyphosphate eliminates ammonia and water in two successive steps as mentioned in this paper, and the final product of degradation is characterised by a crosslinked P-O-P structure formed by elimination of H2O between P-O groups freed by the evolution of NH3.

TL;DR: In this paper, an in-depth account of the complex mechanisms involved in both thermal and photochemical oxidation of polyolefins, with particular emphasis on polypropylene and the interactions that take place thermally.

TL;DR: In this paper, mechanisms are proposed to account for all the products of thermal degradation of bisphenol-A diglycidyl ether and the characteristics of their formation in the overall degradation process.

TL;DR: In this paper, the chain scission and volatilization processes which occur in the thermal degradation of polystyrene have been simulated by Monte Carlo procedures and the results have been compared with the degrees of polymerization, determined experimentally, of poly styrene samples degraded to different extents.

TL;DR: In this paper, the role of the amorphous fraction (fa) of polypropylene resin in its resistance to radiation-induced oxidative degradation is discussed, and the relationship between the relationship is expressed by an empirical equation, 33·5.

TL;DR: In this article, polystyrene, polybutadiene and diblock styrene-butadienes copolymers have been prepared, using sec-butyllithium as initiator, and characterised.

TL;DR: The thermal degradation of polyglycollide has been studied by similar techniques to those used in investigations of polyactide (Part 1 and 2) as discussed by the authors, and it is concluded that the decomposition is complex.

TL;DR: This article showed that polyurethanes prepared by reaction of methylene bis(4-phenylisocyanate) with poly(ethylene glycols) with molecular weights of approximately 1000 and 1500 have been degraded thermally, alone and in the presence of ammonium polyphosphate (APP), at temperatures up to 500°C and the volatile products and structural changes in the residue analysed in detail.

TL;DR: In this paper, a comprehensive mechanism for the overall degradation process has been deduced and discussed, and a detailed analysis of the structural changes in the residual polymer has been carried out at temperatures up to 500°C.

TL;DR: In this article, the photo-thermal oxidation of segmented copoly(ether-ester)s was studied, the behaviour being observed of two polymers with different proportions of polyether.

TL;DR: In this article, the experimental molecular mass decrease in the thermal depolymerization of poly-α-methylstyrene at 240°C in vacuum was simulated by Monte Carlo calculations, performed on the basis of certain hypotheses on the chemical evolution of the two chain radicals formed in a random scission reaction.

TL;DR: In this article, the photostabilising efficiency of copolymers with dodecyl methacrylate (DMA) and octadecyl acrylate was evaluated as stabilisers of photo-oxidation of polypropylene film.

TL;DR: In this paper, the stabilizing effect of a natural antioxidant, sugar cane bagasse-lignin, on the photo-oxidation of a commercial sample of butadiene rubber was investigated in various concentrations, in the pure form, and associated with a diamine or a phosphite stabilizer.

TL;DR: In this paper, a review of catalytic photo-antioxidants is presented, focusing on catalytic chain-breaking antioxidants, which are redox systems which oxidise alkyl radicals (CB-A) and reduce alkylnperoxyl radicals(CB-D) in a cyclical repeating process.

TL;DR: In this article, a comprehensive mechanism for the overall process has been deduced and discussed from the experimental data, and the volatile products and structural changes in the residue have been analyzed in detail.

TL;DR: In this article, the degradation process in the surface regions during X-ray exposure involves a decrease in the nitrate concentration and results in the concomitant evolution of NOx.

TL;DR: In this article, the stabilizing effect of sugar cane bagasse lignin on the thermal and environmental degradation of butadiene rubber was investigated in various concentrations in the pure form and as a substitute for a hindered phenol, in a commercially used formulation also containing a p-phenylene-diamine.

TL;DR: The products of pyrolysis of poly(hexamethylene adipamide), which are volatile at 220°C, have been separated and identified using gas chromatograph-mass spectrometric techniques as discussed by the authors.

TL;DR: In this paper, the physical and chemical changes that occur on the polymer surfaces during the reaction between concentrated sulphuric acid and films of low density polyethylene, high density polyylene, and isotactic polypropylene at 75-125°C have been studied.

TL;DR: In the thermal degradation of some anionic polystyrene samples, chain scission was found to occur in the temperature range 180-220°C as mentioned in this paper, and the resulting polymer molecules thereafter remain stable up to about 280°C.

TL;DR: In this article, the authors used Fick's Law to model the oxidation of a polymer and derived an equation which combines the diffusion-free kinetics of the surface layers of the oxidising sample with the diffusion controlled kinetics which predominate at greater depth.

TL;DR: In this paper, the principal characteristics and products of the thermal degradation of poly(ethylene glycols) (PEG), having molecular weights of 1000 and 1500, with 20% by weight of ammonium polyphosphate (APP), have been determined.

TL;DR: Quinone-tin polymers prepared by the cationic polymerization of p -benzoquinone with tin(II)chloride in the absence of solvent have been investigated as thermal stabilizers for rigid PVC at 180°C in air by measuring the rate of dehydrochlorination as mentioned in this paper.

TL;DR: In this article, isotactic polypropylene (iPP) and high density polyethylene (HDPE) at various compositions have been prepared in a mixer and two different temperatures and various rotational speeds have been used in the experiments.

TL;DR: In this article, it has been shown that polybutadiene has been oxidised at 0-20°C for periods from one day up to several months and also at elevated temperatures.

TL;DR: In this article, the initial transformation products from reactions of zinc dialkyl dithiocarbamates with hydroperoxides have been identified by spectrophotometric and kinetic methods.

TL;DR: In this article, the thermal and antioxidant behavior of a number of commercial monomeric and polymeric hindered piperidine light stabilisers is examined in both low density polyethylene and polypropylene films.