A chain-extender based on 1,1 0 -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. POLYM. ENG. SCI., 54:158-165, 2014. ª

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A monodispersed green masterbatch was produced through an industrial extrusion process, by mixing a commercial Polyamide 6 matrix (PA6) with a halogenated copper phthalocyanine green pigment. The production process was investigated and optimized in order to improve the pigment dispersion, reducing the clogging power and increasing the color strength of the resulting products. The compounding process based on three extrusions without filtration led to a filter pressure value (FPV) reduction of about 84% and a relative color strength (RCS) increase of about 50% with respect to the standard production process (i.e single extrusion). The thermal stability of the prepared compounds was evaluated by rheological test, viscosity measurements, and end group analysis, and it was found that a triple extrusion without filtration promoted thermo-oxidative matrix degradation. However, the same processing conditions led to a significant reduction of the production waste, increasing the productivity and the quality of the final product.

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. J. Appl. Polym. Sci. 2015, 132, 41452.

The production process of a monodispersed blue masterbatch for the coloration of the carpet filaments, constituted by a polyamide 6 (PA6) resin and a copper blue phthalocyanine pigment, was investigated and optimized. It was found that a compounding process based on three extrusions without any subsequent filtration was the best way to achieve a fine pigment dispersion within the PA6 matrix, with a filter pressure value reduction of 50% and a relative color strength increase of about 10% with respect to the standard production process (i.e. a single extrusion). Rheological tests, viscosity measurements and end groups analyses were used to determine the thermal stability of the prepared compounds. It was found that the triple extrusion promoted thermo-oxidative reactions. This innovative process setup can reduce the production waste, increasing the productivity and the quality of the final product without compromising the rheological properties of the monodispersed masterbatches.

This thesis deals with the study of the yarn interlacing. The interlacing process is commonly employed by textile industries to impart cohesion points to a multi-filament yarn. Indeed, this work has been realized in the framework of a collaboration between the Department of Physics of the University of Trento (Italy) and Aquafil S.p.A., a company producing Nylon 6 yarn.