4D-printed materials are an emerging field of research because the physical structure of these novel materials respond to environmental changes. 3D printing techniques have been employed to print a base material with shape memory properties. Geometrical deformations can be observed once an external stimulus triggers the shape memory effect (SME) integrated into the material. The plasticizing effect is a well-known phenomenon where the microscopic polymer chain movements have been altered and reflected in different shape memory behaviour. It has been suggested that a 4D material with localized actuation behaviour can be fabricated by utilizing functionally graded layers made from different degrees of plasticizing. This study demonstrated that a novel 4D material can be fabricated from material extraction continuous printing technique with different loadings of poly(ethylene glycol) (PEG) plasticize, achieving localized thermal recovery. The results indicate that a plasticized functional layer is an effective technique for creating next generation 4D materials.
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http://dx.doi.org/10.1038/s41598-019-55298-1 | DOI Listing |
Ann Ital Chir
December 2024
Department of Cardiovascular Surgery, Shaoxing People's Hospital, 312000 Shaoxing, Zhejiang, China.
Int J Biol Macromol
December 2024
Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, PR China; Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Waihuan Xi Road 100, Guangzhou, Guangdong 510006, PR China.
Lignin, a renewable and biodegradable polymer, offers a promising alternative to petroleum-based polyols for polyurethane elastomer synthesis. However, its complex structure poses challenges, such as poor dispersibility and reactivity. This study introduces a novel one-step and solvent-free method for synthesizing lignin-containing polyurethane elastomers (SF-LPUes-ONE) with a high lignin substitution rate of at least 30 wt%.
View Article and Find Full Text PDFProsthet Orthot Int
December 2024
School of Intelligent Rehabilitation Engineering, Institute of Rehabilitation Engineering and Technology, University of Shanghai for Science and Technology, Shanghai, China.
Background: Prosthetic socket is a key component of the prosthesis for clinical application; its performance directly affects the adaptation of the residual limb to the prosthetic socket. There are long-term and short-term volume fluctuation of the residual limb. The volume fluctuation of the residual limb will lead to the pressure mismatch at the interface of the residual limb and the prosthetic socket, which will cause a series of skin and fit problems.
View Article and Find Full Text PDFInt J Dent
December 2024
College of Dentistry, King Saud University, P. O. Box 68004, Riyadh 11527, Saudi Arabia.
XP-endo files are composed of Max-Wire alloy, which was developed by FKG Dentaire (La Chaux-de-Fonds, Switzerland). This alloy, known as Martensite-Austenite Electropolish Flex, is the first NiTi alloy used in endodontics to combine the shape memory effect with superelasticity for use in clinical practice. This article aims to provide a comprehensive overview of the existing knowledge and evidence regarding different XP-endo files and systems, XP-endo Finisher (XPEF), XP-endo Shaper (XPES), XP-endo Retreatment (XPER), XP-endo Rise (XPE-Rise), and XPE-Rise Retreatment (XPE-Rise-R), to help clinicians understand their different properties and recommended clinical uses.
View Article and Find Full Text PDFSoft Matter
December 2024
Department of Chemical Engineering, Indian Institute of Technology, Madras, Chennai 600036, India.
Reversibly crosslinked polymer networks - polymer networks that can undergo bond association and dissociation reactions - rearrange their structures while maintaining their overall integrity, thus resulting in unique properties such as self-healing, reprocessability, shape memory and adaptability. Here, we show that the introduction of crosslinks, whether reversible or permanent, directly impacts the equilibrium polymer density and hence the material's surface tension. For a limiting case where the bonds are the same size as the polymer chain bonds, simulations, Flory hypotheses and thermodynamic calculations show that the crosslinks induce an increased entropic cohesion in the liquid.
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