Polyethylene terephthalate (PET) is used worldwide for packing, and for this reason, it is the main material in plastic waste. The paper uses granules of recycled PET (R-PET) as raw material for producing filaments for 3D printing, subsequently used for printing the test specimens in different ways: longitudinally and at angles between 10° and 40° in this direction. Both the filaments and the printed specimens experience thermally driven shape memory effect (SME) since they have been able to recover their straight shape during heating, after being bent to a certain angle, at room temperature (RT). SME could be reproduced three times, in the case of printed specimens, and was investigated by cinematographic analysis. Then, differential scanning calorimetry (DSC) was used, in R-PET granules, filaments and 3D printed specimens, to emphasize the existence of glass transition, which represents the governing mechanism of SME occurrence in thermoplastic polymers, as well as a recrystallization reaction. Subsequently, the paper investigated the 3D printed specimens by dynamic mechanical analysis (DMA) using a dual cantilever specimen holder. Temperature (DMA-TS) and isothermal scans (DMA-Izo) were performed, with the aim to discuss the variations of storage modulus and loss modulus with temperature and time, respectively.
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http://dx.doi.org/10.3390/polym14112248 | DOI Listing |
Brain Spine
December 2024
Department of Neurosurgery, University Hospital of Lausanne and University of Lausanne, 1011, Lausanne, Switzerland.
Introduction: While cadaveric dissections remain the cornerstone of education in skull base surgery, they are associated with high costs, difficulty acquiring specimens, and a lack of pathology in anatomical samples. This study evaluated the impact of a hand-crafted three-dimensional (3D)-printed head model and virtual reality (VR) in enhancing skull base surgery training.
Research Question: How effective are 3D-printed models and VR in enhancing training in skull base surgery?
Materials And Methods: A two-day skull base training course was conducted with 12 neurosurgical trainees and 11 faculty members.
Sci Rep
January 2025
Department of Prosthodontics, Yonsei University College of Dentistry, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea.
The effects of heat-assisted vat photopolymerization (HVPP) on the physical and mechanical properties of 3D-printed dental resins, including the morphometric stability of 3D-printed crowns, were investigated. A resin tank was designed to maintain the resin at 30, 40, and 50 ℃ during the 3D printing process. Test specimens were fabricated using a commercial dental resin, with untreated resin serving as the control group.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Key Laboratory of Impact and Safety Engineering (Ningbo University), Ministry of Education, Ningbo 315211, China.
Obtaining reliable dynamic mechanical properties through experiments is essential for developing and validating constitutive models in material selection and structural design. This study introduces a dynamic tensile method using a modified M-type specimen loaded by a split Hopkinson pressure bar (SHPB). A closed M-type specimen was thus employed.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Mechanical Engineering, University of Nevada, Las Vegas, NV 89154, USA.
Dent Mater
January 2025
Department of Cariology, Restorative Sciences and Endodontics, University of Michigan, School of Dentistry, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address:
Regeneration of the multiple tissues and interfaces in the periodontal complex necessitates multidisciplinary evaluation to establish structure/function relationships. This article, an initiative of the Academy of Dental Materials, provides guidance for performing chemical, structural, and mechanical characterization of materials for periodontal tissue regeneration, and outlines important recommendations on methods of testing bioactivity, biocompatibility, and antimicrobial properties of biomaterials/scaffolds for periodontal tissue engineering. First, we briefly summarize periodontal tissue engineering fabrication methods.
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