Rheological and mechanical properties of polyamide 6 modified by electron-beam initiated mediation process

Tuning the Compatibilizer Content and Healing Temperature in Thermally Mendable Polyamide 6/Cyclic Olefin Copolymer Blends

This study presents the formulation and comprehensive characterization of compatibilized polyamide 6 (PA6)/cyclic olefin copolymer (COC) blends with the aim of developing a self-healing matrix for thermoplastic structural composites. Rheological analysis highlighted the compatibilizing effect of ethylene glycidyl methacrylate (E-GMA), as evidenced by an increase in viscosity, melt strength (MS), and breaking stretching ratio (BSR), thus improving the processability during film extrusion. E-GMA also decreased COC domain size and improved the interfacial interaction with PA6, which was at the basis of a higher tensile strength and strain at break compared to neat PA6/COC blends. E-GMA also significantly boosted the healing efficiency (HE), measured via fracture toughness tests in quasi-static and impact conditions. The optimal healing temperature was identified as 160 °C, associated with an HE of 38% in quasi-static mode and 82% in impact mode for the PA6/COC blends with an E-GMA content of 5 wt% (PA6COC_5E-GMA). The higher healing efficiency under impact conditions was attributed to the planar fracture surface, which facilitated the flow of the healing agent in the crack zone, as proven by fractography analysis. This work demonstrates the potential of E-GMA in fine-tuning the thermomechanical properties of PA6/COC blends. PA6COC_5E-GMA emerged as the formulation with the best balance between processability and self-healing efficiency, paving the way for advanced multifunctional self-healing thermoplastic composites for structural applications.

Evaluation of Cross-Linked Polyamide 6 Micro-Indentation Properties: TAIC Concentration and Electron Radiation Intensity

Nowadays, technical practice puts emphasis on improving selected material properties of polymers which could lead to new applications. Material properties can be modified in numerous ways, among which is radiation treatment. This study looks into the influence of beta radiation on several properties of polyamide 6, e.g., indentation hardness, modulus and creep. Main changeable parameters were the concentration of triallyl isocyanurate (TAIC), which promotes cross-linking, and intensity of radiation. The concentration was in the range from 2 to 6 wt.%, while the radiation dose was 0, 66, 99 and 132 kGy. The treated materials were measured for indentation hardness, modulus and creep. Degree of cross-linking was verified by thermo-mechanical analysis (TMA), while degradation processes was investigated by Fourier-transform infrared spectroscopy (FTIR). The results indicate that electron radiation positively affects the tested material properties. The best results were seen in polyamide with 6 wt.% of TAIC, which demonstrated a 38% improvement in mechanical properties after exposure to 132 kGy. This improvement in properties affects the final parts and their application (e.g., in the automotive industry-engine parts; in electrical engineering-insulation of wires and cables; and in industry-pipes for underfloor heating, etc.).

Morphological, Rheological, and Mechanical Properties of Polyamide 6/Polypropylene Blends Compatibilized by Electron-Beam Irradiation in the Presence of a Reactive Agent

An immiscible polyamide 6 (PA6)/polypropylene (PP) blend was compatibilized by electron-beam irradiation in the presence of reactive agent. Glycidyl methacrylate (GMA) was chosen as a reactive agent for interfacial cross-copolymerization between dispersed PP and continuous PA6 phases initiated by electron-beam irradiation. The PA6/PP (80/20) mixture containing GMA was prepared using a twin-screw extruder, and then exposed to an electron-beam at various doses at room temperature to produce compatibilized PA6/PP blends. The morphological, rheological, and mechanical properties of blends produced were investigated. Morphology analysis revealed that the diameter of PP particles dispersed in PA6 matrix was decreased with increased irradiation dose and interfacial adhesion increased due to high surface area of treated PP particles. Complex viscosities (η*) and storage moduli (G’) of blends increased with increasing irradiation dose and were higher than those of PA6 and PP. The complex viscosity of the blend irradiated at 200 kGy was 64 and 8 times higher than PA6 and PP, respectively. The elongation at break of blend irradiated less than 100 kGy was about twice that of PA6. Electron beam treatment improved the compatibility at the interface between PA6 and PP matrix in the presence of GMA.