Search

The use of polymer materials in various fields has increased significantly due to their ease of thermoforming and relatively low production costs. The production volume of these materials is extremely high, and according to forecasts from global statistical centers, it is expected to continue rising in the future. However, the extensive use and easy availability of polymeric materials have caused significant ecological problems. The world faces large amounts of polymer waste and environmental pollution. Plastic recycling remains challenging due to issues related to sorting polymer waste and separating it according to polymer types. Recycling certain plastics requires only a quarter of the energy needed to produce new plastic. To address this, circular economy principles should be applied to 3D printing products made from polymeric materials. A particularly wide application of these technologies is found when polymeric materials are used due to their low cost, low melting temperatures, and other advantageous properties. This paper investigates the impact of plastic recycling on the quality of 3D-printed products. During the research, samples were 3D printed and tested using both virgin and recycled PLA, ABS, and PET-G materials. The samples underwent static and dynamic tests to determine their mechanical properties, such as tensile strength, elongation, and impact resistance. The research results showed that the properties of recycled polymer materials deteriorate, with relative elongation of recycled and 3D-printed materials decreased by 16–45%. Despite this, recycled polymer materials can still be used, but it is necessary to account for the reduction in plasticity when creating products that will be exposed to dynamic loads. The impact strength is reduced by 6% for PLA, 54% for ABS, and 58% for PET-G. Additionally, the research included tests on samples printed with 3D printing technology that were exposed to UV irradiation. The results indicated similar dependences, as UV exposure also affects the reduction of material plasticity. After 66 Wh/m2 of UV radiation, the tensile strength of PET-G and PLA decreased by 17%, while ABS showed a reduction of about 5%. [ABSTRACT FROM AUTHOR]

Conductive hydrogel has drawn great concern in wearable sensors, human-machine interfaces, artificial intelligence (AI), health monitoring, et al. But it still remains challenge to develop hydrogel through facile and sustainable methods. In this work, a conductive, flexible, bendable and self-healing hydrogel (PBCM) composed of polyvinyl alcohol (PVA), borax, cellulose microfibers (CMFs) and MXene nanosheets was fabricated by a simple and efficient strategy. The carboxylated CMFs were extracted from waste ramie fibers via a one-pot ammonium persulfate oxidation method. The crystallinity and tensile strength were increased 70 % and 4 times due to the addition of CMFs and MXene compared to the pristine PVA-borax hydrogel. The incorporation of MXene nanosheets acts as multifunctional cross-linkers and energy transfer platform, promoting the electrical conductivity, stretchability and bendability of hydrogel remarkably. The PBCM-2 hydrogel exhibited the maximum electrical conductivity of 0.81 S/cm. Additionally, the dynamic borate ester linkage imparts self-healing ability to the hydrogel. The resulting PBCM-2 hydrogel demonstrated excellent resistance to fire and pH response properties. Moreover, it showed sensitivity in monitoring various human physiological movements, including finger, wrist, elbow, knee bending and drinking water, indicating its potential for wearable sensing applications like health care and sports training., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)