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Dorigato A.,University of Trento | Brugnara M.,Innovation Center Srl | Giacomelli G.,Aquafil Spa | Fambri L.,University of Trento | Pegoretti A.,University of Trento
Journal of Industrial Textiles | Year: 2014

A commercial organo-modified clay (OMC) was added to a polyamide 6 (PA6) matrix at various concentrations during the polymerization stage or by melt compounding in a twin-screw extruder, and the resulting pellets were used for the production of depth filters in the shape of cylindrical nonwoven webs through a melt-blown process. The processability of the investigated materials was significantly affected by nanofiller introduction. Differential scanning calorimetry revealed that OMCs play a nucleating effect on the crystallization of the polyamide matrix, with a remarkable increase in the crystallization temperature on cooling from the melt. Consequently, a parameter related to the filtering performances of the web, such as the pressure drop (ΔP) evaluated on cylindrical filters, decreased with the increase in die-to-collector distance in a more pronounced way for nanocomposite nonwovens. This behavior was related to the significant decrease of the connecting points in the networks due to the rapid cooling of the filaments on the collecting mandrel. Compressive mechanical tests evidenced how organoclay addition led to a remarkable increase of the rigidity of the web, when the data were compared at the same ΔP value, irrespectively from the preparation technique. © 2014, © The Author(s) 2014. Source


Buccella M.,University of Trento | Dorigato A.,University of Trento | Caldara M.,Aquafil Spa | Pasqualini E.,Aquafil Spa | Fambri L.,University of Trento
Journal of Polymer Research | Year: 2013

A commercial Polyamide 6 (PA6) was melt compounded by using a twin screw extruder with a combination of 1,1′-Carbonyl-Bis-Caprolactam (CBC) and 1,3-Phenylene-Bis-2-Oxazoline (PBO), in order to evaluate their effect on the chain extension behaviour of the resulting materials. An increase of the viscosity values with the chain-extender amount was evidenced by rheological tests on the compounded pellets and relative viscosity measurements on solubilized samples, while the opposite trend was determined increasing the residence time at elevated temperatures. The increase of the molecular weight due to the presence of CBC and PBO was confirmed by the reduction of carboxylic and aminic functionalities evidenced in end group analysis. DSC tests showed a reduction of the melting temperature and of the crystallinity degree proportionally to the chain extender amount. Elastic modulus of the chain-extended materials was similar to that of the corresponding PA6 grades at different molecular weight, while crystallinity drop due to chain extension determined an increase of the strain at break values. © 2013 Springer Science+Business Media. Source


Buccella M.,University of Trento | Dorigato A.,University of Trento | Pasqualini E.,Aquafil Spa | Caldara M.,Aquafil Spa | Fambri L.,University of Trento
Journal of Polymer Research | Year: 2012

A Polycarbonate/Polyamide (PCPA) blend was used as chain extender in a melt compounding process with a Polyamide 6 (PA6), by using a twin screw extruder. The chain extension capability of the PCPA blend was evaluated through rheological, thermal and mechanical tests. Rheological tests on the compounded pellets and relative viscosity measurements on solubilized samples evidenced an increase of the viscosity values with the chain-extender amount and with the high temperature residence time. Terminal group analysis confirmed the increase of the molecular weight with the PCPA content and highlighted a preferential reactivity of the chain extender with amminic end groups. DSC tests showed a slight crystallinity decrease with the PCPA content, while both melting and crystallization temperatures were unaffected. Elastic and yield properties of chain-extended PA6 were similar to that of neat PA6 at differentmolecular weights,while crystallinity drop due to chain extension produced an increase of the strain at break values. © Springer Science+Business Media B.V. 2012. Source


Buccella M.,University of Trento | Dorigato A.,University of Trento | Pasqualini E.,Aquafil Spa | Caldara M.,Aquafil Spa | Fambri L.,University of Trento
Polymer Engineering and Science | Year: 2014

A chain-extender based on 1,1′-Carbonyl-Bis-Caprolactam (CBC) was melt compounded with a commercial Polyamide 6 (PA6) by using a twin screw extruder. Rheological, thermal, and mechanical tests were performed on the resulting materials to evaluate the chain extension capability of CBC. Rheological tests on the compounded pellets and relative viscosity measurements on solubilized samples evidenced an increase of the viscosity values with the chain-extender amount, while the opposite trend was determined increasing the high temperature residence time. Terminal group analysis confirmed the increase of the molecular weight with the CBC content and highlighted a preferential reactivity of the chain-extender with aminic end groups. Differential scanning calorimetry (DSC) tests showed how both melting and relative crystallinity of the up-graded samples decreased with the CBC amount. Elastic and yield properties of chain-extended PA6 were similar to those of neat PA6 grades at different molecular weight, while crystallinity drop due to chain extension was responsible of an increase of the strain at break values. © 2013 Society of Plastics Engineers. Source


Buccella M.,University of Trento | Dorigato A.,University of Trento | Crugnola F.,Aquafil Spa | Caldara M.,Aquafil Spa | Fambri L.,University of Trento
Journal of Applied Polymer Science | Year: 2014

A dioxazine-based color pigment was added to a commercial polyamide 6 (PA6) through an extrusion process, in order to prepare monoconcentrated violet masterbatches through different production set-up. A detailed characterization of the resulting materials was carried out in order to find the best processing parameters combination to optimize pigment dispersion and to reduce the clogging power. The preparation of masterbatches with repeated extrusions markedly reduced the filter pressure value and increased the Relative Color Strength, while filtration did not significantly influence pigment dispersion. Rheological measurements and end-groups analysis were conducted on the same materials with the aim to evaluate their thermal degradation resistance, and the thermal stability of the compounds was retained even upon three extrusions. Therefore, it can be concluded that a proper optimization of the process parameters could lead to an important reduction of the production waste, increasing the quality of the final product. © 2014 Wiley Periodicals, Inc. Source

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