P. Anna
Budapest University of Technology and Economics
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Featured researches published by P. Anna.
Polymer Degradation and Stability | 2002
Gy. Marosi; Andrea Márton; P. Anna; György Bertalan; B. Marosföi; A. Szép
Boroxo siloxanes were used as a ceramic precursor, combined with an intumescent flame retardant additive system, in polypropylene. Varying the composition and content of the precursor characteristic changes of melt viscosity were detected. Chemical interaction of the additives at the temperature of processing, confirmed using Fourier transformed infrared (FTIR) methods, are related with these rheological changes. Raman microscopic analyses were used to obtain better understanding of the chemical changes of the precursor during flame treatment. Interaction between boroxo siloxane and layered silicate (montmorillonite) nanoparticles was investigated using thermogravimetry.
Polymer Degradation and Stability | 2002
X. Almeras; François Dabrowski; M. Le Bras; René Delobel; Serge Bourbigot; Gy. Marosi; P. Anna
The fire performance of intumescent PP/APP/PA6/EVA19 blends were previously put forward in part I of this article. In the present part, the thermal and thermo-oxidative degradations of the formulations are modelled. The comparison between the kinetic data determined in this study and data from previous studies suggests that PP degrades before the reaction between APP and PA6. However it may be supposed that in the conditions of a fire (i.e. at high heating rate) both reactions occur simultaneously. Thus the development of an efficient protective structure is possible which could explain the fire properties of interest observed in the conditions of the cone calorimeter.
Polymer Degradation and Stability | 2002
X. Almeras; François Dabrowski; M. Le Bras; Franck Poutch; Serge Bourbigot; Gy. Marosi; P. Anna
Abstract Addition of the ammonium polyphosphate/polyamide-6 blend is known to enable fire properties of interest to be obtained in many polymers. However, the use of an interfacial agent is required to stabilise the formulation. This study investigates the improvement of the fire performance induced by incorporation of ethylene–butyl acrylate–maleic anhydride (EBuAMA) and ethylene vinyl acetate (EVA x , where x is the vinyl acetate weight level) as interfacial agents of the polypropylene/ammonium polyphosphate/polyamide-6 blend. It is shown that the improvement strongly depends upon both the nature and the amount of interfacial agent used.
Colloids and Surfaces | 1989
Gy. Marosi; Gy. Bertalan; István Rusznák; P. Anna
Abstract Modified interfacial layers were studied in polypropylene—calcium carbonate systems compounded in a single-step process with a surface-active agent and an elastomer simultaneously. Samples with etched and non-etched surfaces were investigated by dielectric spectroscopy and scanning electron microscopy. An increase in the thickness of the interfacial layer was brought about by the increasing elastomer content of the system. However, when the concentration of the latter exceeded a critical upper limit, a new disperse elastomer phase could be observed in the matrix. The value of the critical concentration depends upon the type of elastomer and it is a characteristic parameter for a given polymer—elastomer system. Deformations and failure in the composite system are determined by the interfacial layer. A thick elastomer interphase around the filler particles acts as a bumper layer and stops the crazes. The interactions between the components and the change in the mechanical properties induced by the presence of named additives were also investigated by mechanical spectroscopy.
Polymer Degradation and Stability | 2001
P. Anna; Gy. Marosi; István Csontos; Serge Bourbigot; M. Le Bras; R Delobel
Optimal concentration of boroxo siloxane elastomer synergist was determined by LOI and cone calorimetric measurements on ammonium polyphosphate and pentaerythritol containing intumescent flame retardant for polypropylene. The increased viscosity of the melt and plasticity of intumescent char due to boroxo siloxane elastomer could be proved by a thermal scanning rheometric investigation. It is presumed, the increased melt viscosity is created by the product of boroxo siloxane-pentaerythritol, formed during the compound preparation, while the improved char plasticity is the result of product formed at high temperature from boroxo siloxane and ammonium polyphosphate.
Journal of Polymer Engineering | 1993
Gy. Marosi; György Bertalan; P. Anna; István Rusznák
34 Introduction 34 Materials and Methods 35 Sample Preparation 37 Results and Discussion 37 References 59 Paper submitted for publication August 1991
Macromolecular Materials and Engineering | 2000
Maatoug A. Maatoug; P. Anna; György Bertalan; Imre Ravadits; György Marosi; István Csontos; Andrea Márton; András Tóth
The photodegradation processes of high-density polyethylene (HDPE) films containing either a phthalocyanine-based pigment, or a rutil (TiO 2 )-based pigment, as well as of the unpigmented films stabilised differently were investigated during photo-ageing, applying mechanical, gel content and XPS measurements. The phthalocyanine pigment-containing film showed degradation characteristics (abrupt decrease of elongation at break after short irradiation period, no gel formation, high concentration of oxygen-containg functional groups on the surface) similar to those of the films containing a low amount of stabiliser. The behaviour of the TiO 2 -containing film and that of the unpigmented films containing a higher amount of stabiliser were also similar (slow decrease of elongation at break, increase of gel content, lower amount of oxygen-containing functional groups on the surface). The concentration of oxygen-containing functional groups in samples pigmented with phthalocyanine increased remarkably with increasing processing temperature. The results suggest that the phthalocyanine pigment influences the photostability indirectly, through reduction of the thermal stability of polymer due to the adsorption of the thermal stabiliser by the phthalocyanine pigment. Coating the surface of phthalocyanine with reactive surfactant improved the photostability of the HDPE film.
Journal of Thermal Analysis and Calorimetry | 1997
Gy. Marosi; P. Anna; I. Balogh; Gy. Bertalan; A. Tohl; M.A. Maatoug
Engineering application of polypropylene requires the employment of flame retardants. Reactive compounding of ammonium-polyphosphate and synergist additives with polypropylene is an effective way for forming flame retardant polypropylene. Both the ammonium-polyphosphate and the additives used for improving its performance effect the crystallization and melting behavior of polypropylene. Encapsulation of flame retardant additives with appropriate elastomer, in order to improve their water resistancy, causes further changes in degree of crystallinity and consequently in the mechanical properties.
Polymer Degradation and Stability | 2001
P. Anna; Gy. Bertalan; Gy. Marosi; I. Ravadits; M.A. Maatoug
The deterioration of differently stabilised and pigmented high density polyethylene films was investigated by DSC and UV spectroscopy methods in the course of accelerated photo-ageing and compared to earlier XPS and gel-content results. Unexpectedly quick destruction of phthalocyanine containing film was observed and explained by the adsorptive removal of the stabiliser from the polymer matrix. In the pigment (filler)-solvent-stabiliser model systems the high susceptibility of hindered phenol type heat-stabiliser to adsorb on talc and phthalocyanine pigment was proved by UV spectroscopic measurements. Surface coating of the talc and pigment with a reactive surfactant considerable reduced the adsorption capacity and thus improved the photo-stability of the pigmented film.
Journal of Fire Sciences | 2004
X. Almeras; Michel Le Bras; Peter R. Hornsby; Serge Bourbigot; György Marosi; P. Anna; René Delobel
The first part of this work deals with the effect of ageing (artificial weathering) on an intumescent flame-retarded ammonium polyphosphate (APP)/polyamide-6 (PA-6)/polypropylene (PP) blend. The study of the fire properties using the cone calorimeter shows a decrease in the performance caused by the artificial weathering. The chemical modifications of the blends after ageing are investigated by solid state 31P NMR and SEM. It is shown that APP is degraded into ortho-, pyrophosphate and short chain polyphosphates. These modifications lead to the loss of the ammonium contents which could explain the decrease of fire performance. Moreover, some morphological changes appear which may lead to the change of fire and mechanical properties. A classical solution for re-using the material is the recycling. In the second part of this study, we examine the effect of recycling simulated by a multi-extrusion process. This treatment induces modifications which are different from those resulting from the effect of ageing. So, morphological and chemical changes induced by recycling are compared to the effects of ageing. It is shown that after recycling APP is also degraded in the same way as after ageing. In addition to the degradation of APP, a decrease in phosphorous concentration is observed which is attributed to the migration of phosphate species.