This study aims to analyze strength properties and low-cycle dynamic tests of composite materials modified with glass and basalt fibers. Biopolyamide 4.10 was used as the matrix, and the fiber contents were 15, 30, and 50% by weight. Static tensile tests, impact tests, and determination of mechanical hysteresis loops were carried out as strength tests. The length of the fibers in the produced composites and their processing properties were determined. The composite materials were compared with commercially available glass fiber-reinforced composites with 30 and 50% fiber contents. The results showed that such composites can successfully replace composite materials based on petroleum-based polymeric materials, providing high strength properties and reducing the negative environmental impact by using renewable sources. Composites with 30% basalt fiber composition were characterized by higher tensile strength by about 60% compared to commercially available composites with 30% glass fiber composition and an almost doubly increased Young’s modulus. Increasing the content of basalt fibers to 50% results in a further increase in strength properties. Despite the lower tensile strength compared to polyamide 6 with 50% glass fiber content, basalt fibers provided an approximately 10% higher modulus of elasticity.

The electric motor industry has witnessed fast growth in recent years thanks to adoption of electrical vehicles, expansion of data center and increasing demand of higher efficiency across industries. Other features of the motor, including compact structure and winding encapsulation, are also desired. These requirements consequently lead to excessive temperature rise which is detrimental to the safe operation of machines. Thus, effective thermal management in electric motors attracts growing interests in motor design as well as manufacturing. This paper summarizes efforts made on motor thermal management, especially in water-cooling strategy for totally enclosed non-ventilated induction motor with polymer encapsulated stator windings. Based on the lesson learned through theoretical study, a water-cooling system composed of a single-turn copper tubing wound around the end-windings of an induction motor is prototyped and tested. The thermal test demonstrates the effectiveness of water-cooling which leads to over 60 % reduction in temperature rise compared to a regular non water-cooled motor. At the same time, minimal impact of this cooling construction on the no-load losses suggests the presence of copper cooling circuit next to the end-winding does not have noticeably negative impact on the machine losses.

This study aims to evaluate the influence of glass fibre (GF) type and content on the thermal, mechanical, and morphological properties of polyethylene terephthalate (PET)-based composites containing post-consumer PET flakes, intended for mouldings exposed to cementitious environments (e.g., anchors). Two chemically resistant GFs were compared: alkali-resistant (AR) fibres with soft sizing (SGFs) and electrical-/chemical-resistant (ECR) fibres with hard sizing (HGFs). Composites with fibre contents of 10–60 wt.% were prepared, with detailed analysis focused on 30 to 50 wt.%—the range typical for practical applications. AR fibres experienced greater shortening during processing, and their actual fibre content was lower than the intended value. Differential scanning calorimetry (DSC) revealed enhanced crystallisation kinetics for SGF composites, with higher crystallinity of the injection-moulded samples and elevated crystallisation temperatures (206–208 °C for SGF vs. 196–197 °C for HGF). Thermogravimetric analysis (TGA) indicated that thermal stability was primarily governed by fibre content; both SGF and HGF composites showed improved resistance compared to neat PET. Mechanical tests demonstrated that both fibre types effectively reinforced the matrix: HGF composites exhibited a higher elastic modulus (20.6 GPa for HGF-50 vs. 18.3 GPa for SGF-50), whereas SGF composites exhibited roughly 10–20% higher tensile, flexural, and impact strength, despite slightly lower fibre content. SEM analysis confirmed more uniform fibre distribution and fewer voids in SGF composites. These results highlight the importance of GF selection for PET composites in alkaline environments, taking into account the properties of the sizing film former and balancing trade-offs between mechanical performance, thermal stability, processability, and economic factors.

W artykule omówiono recykling opakowań PET, podkreślając jego znaczenie w gospodarce obiegu zamkniętego. Przedstawiono metody przetwórstwa odzyskanego materiału i jego potencjalne zastosowania w różnych sektorach gospodarki. Wykazano znaczenie zasady 6R w integracji gospodarki i promowaniu zrównoważonego rozwoju.

In this study we investigate the effect of moisture content on the dielectric breakdown strength and glass transition temperature (T_g) of bio-polyamide 4.10 reinforced with glass or basalt fiber (15, 30, 50 wt%). Moisture absorption decreased with increasing fiber content, regardless of fiber type. The reduction in breakdown voltage (BDV) was more pronounced in the composites with higher moisture content reinforced with basalt fiber. This may be due to weaker interactions at the interface. The presence of moisture decreased the glass transition temperature of the composites. PA 4.10, especially reinforced with glass fiber, is characterized by better performance properties than PA 6.6 reinforced with 50 wt% glass fiber in applications requiring both stability of mechanical properties and dielectric properties.