Tamás Igricz - Academia.edu (original) (raw)

Papers by Tamás Igricz

Research paper thumbnail of Design of Interlayers for Fire-Retarded Polymeric Systems

Fire Retardancy of Polymeric Materials, Second Edition, 2009

Research paper thumbnail of Flame retarded self-reinforced poly(lactic acid) composites of outstanding impact resistance

Composites Part A: Applied Science and Manufacturing, 2015

ABSTRACT Impact resistant all-poly(lactic acid) composites were prepared by film-stacking of high... more ABSTRACT Impact resistant all-poly(lactic acid) composites were prepared by film-stacking of highly crystalline poly(lactic acid) (PLA) fibres with fully amorphous PLA films. The flammability of the self-reinforced PLA composites (PLA-SRCs) was effectively reduced by incorporating ammonium polyphosphate based flame retardant (FR) additive and montmorillonite clays in a weight ratio of 10 to 1 into the matrix layers. As low as 16 wt% FR content proved to be sufficient for achieving self-extinguishing behaviour, i.e. UL94 V-0 rating, and to achieve 50% and 40% reduction of peak of heat release rate and total heat emission, respectively. The introduction of FR additives improved also important mechanical properties compared to the FR-free all-PLA composite. The stiffness of the PLA-SRCs increased steadily with the FR contents of their matrix layers, furthermore, owing to the improved fibre-matrix bonding, prominent energy absorption capacity (impact perforation energy as high as 16 J/mm) was determined for the effectively flame retarded PLA-SRC.

Research paper thumbnail of Self-extinguishing polypropylene with a mass fraction of 9% intumescent additive II – Influence of highly oriented fibres

Polymer Degradation and Stability, 2013

Recently, noticeably enhanced flame retardancy of multilayered self-reinforced composites, flame ... more Recently, noticeably enhanced flame retardancy of multilayered self-reinforced composites, flame retarded with common ammonium polyphosphate based intumescent system, was described. In this paper the observed novel flame retardant synergism between intumescent additive system and highly oriented polymer fibres is further studied. The ignitability and combustion behaviour of flame retarded multilayer self-reinforced composites were compared to flame retardant compounds, prepared by simple melt compounding, of identical low additive contents, both when the heat was applied parallel (UL-94 tests) and perpendicular (cone calorimetric tests) with the direction of the embedded oriented tapes in self-reinforced composites. SEM and EDS analyses supported the different foaming process of the two types of samples to be understood, while the structure and character of the finally (after combustion) obtained charred layers were examined by compression tests. Considering the results of all the applied testing methods, the complex picture of the mechanism behind the enhanced flame retardant efficiency of flame retarded self-reinforced composites could be clarified.

Research paper thumbnail of Development of flame retarded self-reinforced composites from automotive shredder plastic waste

Polymer Degradation and Stability, 2012

Research paper thumbnail of Testing the performance of pure spectrum resolution from Raman hyperspectral images of differently manufactured pharmaceutical tablets

Analytica Chimica Acta, 2012

Chemical imaging is a rapidly emerging analytical method in pharmaceutical technology. Due to the... more Chemical imaging is a rapidly emerging analytical method in pharmaceutical technology. Due to the numerous chemometric solutions available, characterization of pharmaceutical samples with unknown components present has also become possible. This study compares the performance of current state-of-the-art curve resolution methods (multivariate curve resolution-alternating least squares, positive matrix factorization, simplex identification via split augmented Lagrangian and self-modelling mixture analysis) in the estimation of pure component spectra from Raman maps of differently manufactured pharmaceutical tablets. The batches of different technologies differ in the homogeneity level of the active ingredient, thus, the curve resolution methods are tested under different conditions. An empirical approach is shown to determine the number of components present in a sample. The chemometric algorithms are compared regarding the number of detected components, the quality of the resolved spectra and the accuracy of scores (spectral concentrations) compared to those calculated with classical least squares, using the true pure component (reference) spectra. It is demonstrated that using appropriate multivariate methods, Raman chemical imaging can be a useful tool in the non-invasive characterization of unknown (e.g. illegal or counterfeit) pharmaceutical products.

Research paper thumbnail of Predicting final product properties of melt extruded solid dispersions from process parameters using Raman spectrometry

Journal of pharmaceutical and biomedical analysis, 2014

Raman spectrometry was utilized to estimate degraded drug percentage, residual drug crystallinity... more Raman spectrometry was utilized to estimate degraded drug percentage, residual drug crystallinity and glass-transition temperature in the case of melt-extruded pharmaceutical products. Tight correlation was shown between the results obtained by confocal Raman mapping and transmission Raman spectrometry, a PAT-compatible potential in-line analytical tool. Immediate-release spironolactone-Eudragit E solid dispersions were the model system, owing to the achievable amorphization and the heat-sensitivity of the drug compound. The deep investigation of the relationship between process parameters, residual drug crystallinity and degradation was performed using statistical tools and a factorial experimental design defining 54 different circumstances for the preparation of solid dispersions. From the examined factors, drug content (10, 20 and 30%), temperature (110, 130 and 150°C) and residence time (2.75, 11.00 and 24.75min) were found to have significant and considerable effect. By forming...

Research paper thumbnail of Design of Interlayers for Fire-Retarded Polymeric Systems

Fire Retardancy of Polymeric Materials, Second Edition, 2009

Research paper thumbnail of Flame retarded self-reinforced poly(lactic acid) composites of outstanding impact resistance

Composites Part A: Applied Science and Manufacturing, 2015

ABSTRACT Impact resistant all-poly(lactic acid) composites were prepared by film-stacking of high... more ABSTRACT Impact resistant all-poly(lactic acid) composites were prepared by film-stacking of highly crystalline poly(lactic acid) (PLA) fibres with fully amorphous PLA films. The flammability of the self-reinforced PLA composites (PLA-SRCs) was effectively reduced by incorporating ammonium polyphosphate based flame retardant (FR) additive and montmorillonite clays in a weight ratio of 10 to 1 into the matrix layers. As low as 16 wt% FR content proved to be sufficient for achieving self-extinguishing behaviour, i.e. UL94 V-0 rating, and to achieve 50% and 40% reduction of peak of heat release rate and total heat emission, respectively. The introduction of FR additives improved also important mechanical properties compared to the FR-free all-PLA composite. The stiffness of the PLA-SRCs increased steadily with the FR contents of their matrix layers, furthermore, owing to the improved fibre-matrix bonding, prominent energy absorption capacity (impact perforation energy as high as 16 J/mm) was determined for the effectively flame retarded PLA-SRC.

Research paper thumbnail of Self-extinguishing polypropylene with a mass fraction of 9% intumescent additive II – Influence of highly oriented fibres

Polymer Degradation and Stability, 2013

Recently, noticeably enhanced flame retardancy of multilayered self-reinforced composites, flame ... more Recently, noticeably enhanced flame retardancy of multilayered self-reinforced composites, flame retarded with common ammonium polyphosphate based intumescent system, was described. In this paper the observed novel flame retardant synergism between intumescent additive system and highly oriented polymer fibres is further studied. The ignitability and combustion behaviour of flame retarded multilayer self-reinforced composites were compared to flame retardant compounds, prepared by simple melt compounding, of identical low additive contents, both when the heat was applied parallel (UL-94 tests) and perpendicular (cone calorimetric tests) with the direction of the embedded oriented tapes in self-reinforced composites. SEM and EDS analyses supported the different foaming process of the two types of samples to be understood, while the structure and character of the finally (after combustion) obtained charred layers were examined by compression tests. Considering the results of all the applied testing methods, the complex picture of the mechanism behind the enhanced flame retardant efficiency of flame retarded self-reinforced composites could be clarified.

Research paper thumbnail of Development of flame retarded self-reinforced composites from automotive shredder plastic waste

Polymer Degradation and Stability, 2012

Research paper thumbnail of Testing the performance of pure spectrum resolution from Raman hyperspectral images of differently manufactured pharmaceutical tablets

Analytica Chimica Acta, 2012

Chemical imaging is a rapidly emerging analytical method in pharmaceutical technology. Due to the... more Chemical imaging is a rapidly emerging analytical method in pharmaceutical technology. Due to the numerous chemometric solutions available, characterization of pharmaceutical samples with unknown components present has also become possible. This study compares the performance of current state-of-the-art curve resolution methods (multivariate curve resolution-alternating least squares, positive matrix factorization, simplex identification via split augmented Lagrangian and self-modelling mixture analysis) in the estimation of pure component spectra from Raman maps of differently manufactured pharmaceutical tablets. The batches of different technologies differ in the homogeneity level of the active ingredient, thus, the curve resolution methods are tested under different conditions. An empirical approach is shown to determine the number of components present in a sample. The chemometric algorithms are compared regarding the number of detected components, the quality of the resolved spectra and the accuracy of scores (spectral concentrations) compared to those calculated with classical least squares, using the true pure component (reference) spectra. It is demonstrated that using appropriate multivariate methods, Raman chemical imaging can be a useful tool in the non-invasive characterization of unknown (e.g. illegal or counterfeit) pharmaceutical products.

Research paper thumbnail of Predicting final product properties of melt extruded solid dispersions from process parameters using Raman spectrometry

Journal of pharmaceutical and biomedical analysis, 2014

Raman spectrometry was utilized to estimate degraded drug percentage, residual drug crystallinity... more Raman spectrometry was utilized to estimate degraded drug percentage, residual drug crystallinity and glass-transition temperature in the case of melt-extruded pharmaceutical products. Tight correlation was shown between the results obtained by confocal Raman mapping and transmission Raman spectrometry, a PAT-compatible potential in-line analytical tool. Immediate-release spironolactone-Eudragit E solid dispersions were the model system, owing to the achievable amorphization and the heat-sensitivity of the drug compound. The deep investigation of the relationship between process parameters, residual drug crystallinity and degradation was performed using statistical tools and a factorial experimental design defining 54 different circumstances for the preparation of solid dispersions. From the examined factors, drug content (10, 20 and 30%), temperature (110, 130 and 150°C) and residence time (2.75, 11.00 and 24.75min) were found to have significant and considerable effect. By forming...