scholarly journals Thioxanthone Derivatives as a New Class of Organic Photocatalysts for Photopolymerisation Processes and the 3D Printing of Photocurable Resins under Visible Light

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 903
Author(s):  
Emilia Hola ◽  
Maciej Pilch ◽  
Joanna Ortyl

In the present paper, novel thioxanthone-based compounds were synthesised and evaluated as a component of photoredox catalysts/photoinitiating systems for the free-radical polymerisation (FRP) of acrylates and the ring-opening cationic polymerisation (CP) of epoxy monomers. The performance of the obtained thioxanthones in two- and three-component photoinitiating systems, in combination with amines, iodonium or sulphonium salt, as well as with alkyl halide, for photopolymerisation processes upon exposure to light emitting diodes (LEDs) with a maximum emission of 405 nm and 420 nm, was investigated. The studied compounds act also as one-component free-radical photoinitiators. Fourier transform real-time infrared spectroscopy was used to monitor the kinetics of disappearance of the functional groups of the monomers during photoinitiated polymerisation. Excellent photoinitiating efficiency and high final conversions of functional groups were observed. Moreover, the influence of thioxanthone skeleton substitution on photoinitiating efficiency was discussed. The photochemical mechanism was also investigated through cyclic voltammetry. It was discovered that thioxanthone derivatives can be used as a metal-free photoredox catalyst active for both oxidative and reductive cycles. Furthermore, a photopolymerizable system based on novel thioxanthone derivatives in a stereolithography three-dimensional (3D) printing technology under visible sources of light was used. The effects of photoinitiator type system and monomer type in photoresins during 3D printing processes were explored. The outcome of this research is the development of high-performance visible photosensitive resins with improved photosensitivity obtained thanks to the development of entirely novel photoinitiating systems specifically adapted for this application.

Nanoscale ◽  
2013 ◽  
Vol 5 (17) ◽  
pp. 7906 ◽  
Author(s):  
Qin-qin Xiong ◽  
Jiang-ping Tu ◽  
Xin-hui Xia ◽  
Xu-yang Zhao ◽  
Chang-dong Gu ◽  
...  

2015 ◽  
Vol 137 (08) ◽  
pp. 42-45
Author(s):  
Mike Vasquez

This article reviews the challenges for companies while adopting three-dimensional (3D) printing technology. A big challenge for companies figuring out whether they need to invest in 3-D printing is the different types of printing systems available in the market. At a high level, there are seven different families of 3-D printing processes. Each of the seven technologies is differentiated by the materials used and how the materials are fused together to create three-dimensional objects. Another barrier is that most companies have not yet found it viable to put the processes in place to incorporate the change in design, engineering, and manufacturing production that is required. Not only capital funds are needed to purchase machines, but to effectively use the technology to create a sellable product, one also needs to have a targeted product line and clear vision of the ways that 3-D printing can help lower material costs, save energy, and simplify manufacturing and assembly.


Author(s):  
Yao Li ◽  
Kaimin Du ◽  
Manli Zhang ◽  
Xuan Gao ◽  
Yu Lu ◽  
...  

Metal halide perovskites are a new class of promising materials in optoelectronic applications. As optoelectronic properties of the lead halide perovskites are determined largely by their morphology, the morphology of...


2020 ◽  
Vol 13 (2) ◽  
pp. 503-510 ◽  
Author(s):  
Xuesong Xie ◽  
Shuquan Liang ◽  
Jiawei Gao ◽  
Shan Guo ◽  
Jiabao Guo ◽  
...  

We report a new class of Zn anodes modified by a three-dimensional nanoporous ZnO architecture (Zn@ZnO-3D), which can accelerate the kinetics of Zn2+ transfer and deposition, inhibit dendrite growth, and reduce the side-reactions.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 124 ◽  
Author(s):  
Mohammad A. Azad ◽  
Deborah Olawuni ◽  
Georgia Kimbell ◽  
Abu Zayed Md Badruddoza ◽  
Md. Shahadat Hossain ◽  
...  

Three dimensional (3D) printing as an advanced manufacturing technology is progressing to be established in the pharmaceutical industry to overcome the traditional manufacturing regime of 'one size fits for all'. Using 3D printing, it is possible to design and develop complex dosage forms that can be suitable for tuning drug release. Polymers are the key materials that are necessary for 3D printing. Among all 3D printing processes, extrusion-based (both fused deposition modeling (FDM) and pressure-assisted microsyringe (PAM)) 3D printing is well researched for pharmaceutical manufacturing. It is important to understand which polymers are suitable for extrusion-based 3D printing of pharmaceuticals and how their properties, as well as the behavior of polymer–active pharmaceutical ingredient (API) combinations, impact the printing process. Especially, understanding the rheology of the polymer and API–polymer mixtures is necessary for successful 3D printing of dosage forms or printed structures. This review has summarized a holistic materials–process perspective for polymers on extrusion-based 3D printing. The main focus herein will be both FDM and PAM 3D printing processes. It elaborates the discussion on the comparison of 3D printing with the traditional direct compression process, the necessity of rheology, and the characterization techniques required for the printed structure, drug, and excipients. The current technological challenges, regulatory aspects, and the direction toward which the technology is moving, especially for personalized pharmaceuticals and multi-drug printing, are also briefly discussed.


2021 ◽  
Vol 8 ◽  
Author(s):  
Chuangye Ge ◽  
Qianru Fang ◽  
Haoran Lin ◽  
Hanlin Hu

Perovskite-based light-emitting diodes (PLEDs) have emerged as a promising alternative owning to the excellent optoelectronic properties including narrow emission linewidths, high photoluminescence quantum yield (PLQY), tunable emission wavelength, and high color purity. Over the past several years, significant progress has been obtained for green, red, and near-infrared PLEDs with a high external quantum efficiency (EQE) of over 20%. However, the development of blue PLEDs has been limited by several technical issues including poor film quality, inefficient device structure, higher trap density, and so on. To overcome these drawbacks with improved PLQY and EQE, we summarize and analyze the recent advances towards the development of three dimensional (3D), two dimensional (2D) and quasi-2D perovskites film employing composition and/or dimensional engineering. Moreover, the utilization of perovskite nanocrystals (PNCs) is also considered as a feasible strategy for the realization of high-performance blue PLEDs. We systematically evaluate the performance of sky-blue, pure-blue and deep blue PLEDs based on different perovskite materials. Finally, future prospective are proposed to promote the development of efficient blue PLEDs.


Author(s):  
Filippo Cucinotta ◽  
Marcello Raffaele ◽  
Fabio Salmeri

AbstractStochastic lattice structures are very powerful solutions for filling three-dimensional spaces using a generative algorithm. They are suitable for 3D printing and are well appropriate to structural optimization and mass distribution, allowing for high-performance and low-weight structures. The paper shows a method, developed in the Rhino-Grasshopper environment, to distribute lattice structures until a goal is achieved, e.g. the reduction of the weight, the harmonization of the stresses or the limitation of the strain. As case study, a cantilever beam made of Titan alloy, by means of SLS technology has been optimized. The results of the work show the potentiality of the methodology, with a very performing structure and low computational efforts.


2022 ◽  
pp. 004051752110698
Author(s):  
Chuanli Su ◽  
Guangwei Shao ◽  
Qinghua Yu ◽  
Yaoli Huang ◽  
Jinhua Jiang ◽  
...  

Highly conductive, flexible, stretchable and lightweight electrode substrates are essential to meet the future demand on supercapacitors for wearable electronics. However, it is difficult to achieve the above characteristics simultaneously. In this study, ultrafine stainless-steel fibers (with a diameter of ≈30 μm) are knitted into stainless-steel meshes (SSMs) with a diamond structure for the fabrication of textile stretchable electrodes and current collectors. The electrodes are fabricated by utilizing an electrodeposited three-dimensional network graphene framework and poly(3,4-ethylenedioxythiophene) (PEDOT) coating on the SSM substrates via a two-step electrodeposition process, which show a specific capacitance of 77.09 F g−1 (0.14 A g−1) and superb cycling stability (91% capacitance retention after 5000 cycles). Furthermore, the assembled flexible stretchable supercapacitor based on the PEDOT/reduced graphene oxide (RGO)@SSM electrodes exhibits an areal capacitance (53 mF cm−2 at 0.1 mA cm−2), a good cycling stability (≈73% capacitance retention after 5000 cycles), rate capability (36 mF cm−2 at 5 mA cm−2), stretchable stability (≈78% capacitance retention at 10% strain for 500 stretching cycles) and outstanding flexibility and stability under various bending deformations. The assembled supercapacitors can illuminate a thermometer and a light-emitting diode, demonstrating their potential application as stretchable supercapacitors. This simple and low-cost method developed for fabricating lightweight, stretchable and stable high-performance supercapacitors offers new opportunities for future stretchable electronic devices.


2021 ◽  
Vol 23 (4) ◽  
pp. 193-200
Author(s):  
N.K. Tolochko ◽  

It is problematic to apply traditional microtechnologies for the manufacturing three-dimensional (3D) components of microsystems due to a number of inherent disadvantages. It is much more promising to use additive technologies for these purposes. In present paper various additive technologies used for manufacturing non-electronic components of microsystems as well as various non-electronic components manufactured using these technologies are considered. The peculiarities of the implementation of additive technologies in the manufacture of non-electronic microcomponents are discussed. More than 20 types of additive technologies characterized by different principles for the implementation of 3D printing processes are presented and their brief description is given. Most of these technologies allow manufacturing the components with micrometer feature sizes and some of them — with nanometer feature sizes. Microcomponents produced by additive technologies are intended for use in micromechanics, microoptics and microfluidics. Many examples of such microcomponents are given with indication of their typical feature sizes. Additive technologies make it possible to create both individual parts of microdevices and completely finished micro-devices. Microcomponents are mainly made from photopolymers and thermoplastics, as well as metals. Among additive technologies those that provide the multi-material 3D printing as well as the embedding of discrete components into printed microdevices are especially promising. It is expected that in near future additive technologies will be widely used in the production of various non-electronic components of microsystems.


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