INTRODUCTION Composite materials have gained great attention in many industrial fields, such as automotive, aerospace and aeronautical. The addition of glass or carbon fibres to polymer matrices allows the improvement of mechanical properties, keeping weight at lower values compared to metal manufactures. Traditionally, thermoset polymers are used as matrices thanks to their mechanical properties and also easiness of textile impregnation before curing process. However, thermosets are not recyclable. As a consequence, thermoplastic matrices develop as a valuable alternative. Nylon 6, in particular, seems to be an optimal polymer because of its cheapness, very good impregnation deriving from monomer reaction process and good properties. The aim of this work is an in-situ polymerization of Nylon 6, analysing the influence of processing parameters on Nylon 6 properties. MATERIAL AND METHODS PA6 polymerization is performed starting from caprolactam, an activator (solid solution of a caprolactam blocked isocyanate in caprolactam) and a catalyst (solid solution of sodium caprolactamate in caprolactam). Products (Addonyl CR) are provided by Lanxess. RESULTS AND DISCUSSION Two mixtures, composed by caprolactam, catalyst and activator, are dried at 40°C for 30 minutes under argon atmophere. They are molten at 80°C, degassed under stirring and transferred in the mixing unit with low viscosity. The reactive mixture is transferred in an aluminium mould, containing a dog-bone specimen shaped mask, at the desired polymerization temperature. Once the filling is complete, the reaction is given 10 to 30 minutes to reach the maximum conversion, then the mould is cooled and the material is demoulded. The influence of mould temperature on PA6 properties has been evaluated with tensile tests and DSC. In fact, a correlation between mechanical properties, macromolecular length and reaction temperature can be extrapolated. Indeed, Nylon-6 specimens have been produced at various mould temperatures, then physical and mechanical properties will be revealed by DSC and tensile test.

INJECTION REACTIVE PA6 MOULDING: EFFECT OF MOULD TEMPERATURE ON POLYMER CHARACTERISTICS / Marini, D; Quitadamo, A; Sambucci, M; Lucignani, V; Bracciale, Mp; Santarelli, Ml; Valente, M. - (2019). ((Intervento presentato al convegno XII CONVEGNO INSTM SULLA SCIENZA E TECNOLOGIA DEI MATERIALI XV CONVEGNO NAZIONALE AIMAT tenutosi a Ischia (NA).

INJECTION REACTIVE PA6 MOULDING: EFFECT OF MOULD TEMPERATURE ON POLYMER CHARACTERISTICS

Marini D
;
Quitadamo A;SAMBUCCI, MATTEO;Bracciale MP;Santarelli ML;Valente M
2019

Abstract

INTRODUCTION Composite materials have gained great attention in many industrial fields, such as automotive, aerospace and aeronautical. The addition of glass or carbon fibres to polymer matrices allows the improvement of mechanical properties, keeping weight at lower values compared to metal manufactures. Traditionally, thermoset polymers are used as matrices thanks to their mechanical properties and also easiness of textile impregnation before curing process. However, thermosets are not recyclable. As a consequence, thermoplastic matrices develop as a valuable alternative. Nylon 6, in particular, seems to be an optimal polymer because of its cheapness, very good impregnation deriving from monomer reaction process and good properties. The aim of this work is an in-situ polymerization of Nylon 6, analysing the influence of processing parameters on Nylon 6 properties. MATERIAL AND METHODS PA6 polymerization is performed starting from caprolactam, an activator (solid solution of a caprolactam blocked isocyanate in caprolactam) and a catalyst (solid solution of sodium caprolactamate in caprolactam). Products (Addonyl CR) are provided by Lanxess. RESULTS AND DISCUSSION Two mixtures, composed by caprolactam, catalyst and activator, are dried at 40°C for 30 minutes under argon atmophere. They are molten at 80°C, degassed under stirring and transferred in the mixing unit with low viscosity. The reactive mixture is transferred in an aluminium mould, containing a dog-bone specimen shaped mask, at the desired polymerization temperature. Once the filling is complete, the reaction is given 10 to 30 minutes to reach the maximum conversion, then the mould is cooled and the material is demoulded. The influence of mould temperature on PA6 properties has been evaluated with tensile tests and DSC. In fact, a correlation between mechanical properties, macromolecular length and reaction temperature can be extrapolated. Indeed, Nylon-6 specimens have been produced at various mould temperatures, then physical and mechanical properties will be revealed by DSC and tensile test.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11573/1304069
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