scholarly journals Mono vs. Difunctional Coumarin as Photoinitiators in Photocomposite Synthesis and 3D Printing

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1202
Author(s):  
Mahmoud Rahal ◽  
Haifaa Mokbel ◽  
Bernadette Graff ◽  
Joumana Toufaily ◽  
Tayssir Hamieh ◽  
...  
Keyword(s):  
Molecular Weight ◽  
3D Printing ◽  
High Molecular Weight ◽  
Photophysical Properties ◽  
Glass Fibers ◽  
General Rule ◽  
Point Of View ◽  
Polymerization Process ◽  
Coumarin Derivatives ◽  
Acrylate Monomers

This work is devoted to investigate three coumarin derivatives (Coum1, Coum2, and Coum3), proposed as new photoinitiators of polymerization when combined with an additive, i.e., an iodonium salt, and used for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions. The different coumarin derivatives can also be employed in three component photoinitiating systems with a Iod/amine (ethyl 4-dimethylaminobenzoate (EDB) or N-phenylglycine (NPG)) couple for FRP upon irradiation with an LED @ 405 nm. These compounds showed excellent photoinitiating abilities, and high polymerization rates and final conversions (FC) were obtained. The originality of this work relies on the comparison of the photoinitiating abilities of monofunctional (Coum1 and Coum2) vs. difunctional (Coum3) compounds. Coum3 is a combined structure of Coum1 and Coum2, leading to a sterically hindered chemical structure with a relatively high molecular weight. As a general rule, a high molecular weight should reduce the migration of initiating molecules and favor photochemical properties such as photobleaching of the final polymer. As attempted, from the efficiency point of view, Coum3 can initiate the FRP, but a low reactivity was observed compared to the monofunctional compound (Coum1 and Coum2). Indeed, to study the photochemical and photophysical properties of these compounds, different parameters were taken into account, e.g., the light absorption and emission properties, steady state photolysis, and fluorescence quenching. To examine these different points, several techniques were used including UV-visible spectroscopy, real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), fluorescence spectroscopy, and cyclic voltammetry. The photochemical mechanism involved in the polymerization process is also detailed. The best coumarins investigated in this work were used for laser writing (3D printing) experiments and also for photocomposite synthesis containing glass fibers.

Microwave-assisted polymerization process: A way to design new, high molecular weight poly(arylimidazole)s

Polymer ◽  
2008 ◽  
Vol 49 (24) ◽  
pp. 5209-5214 ◽  
Author(s):  
Edouard Chauveau ◽  
Catherine Marestin ◽  
Vincent Martin ◽  
Régis Mercier
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polymerization Process ◽  
Microwave Assisted ◽  
High Molecular Weight Poly

scholarly journals Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s

2018 ◽  
Author(s):  
Martina Rimmele ◽  
Klaus Ableidinger ◽  
Adam V. Marsh ◽  
Nathan J. Cheetham ◽  
M. Josef Taublaender ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Cost ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Phenylene Vinylene ◽  
Structural Variations ◽  
Interesting Class ◽  
New Applications ◽  
Exceptional Stability

Poly(p-phenylene vinylene)s (PPVs) have been studied for decades, but research on this interesting class of conjugated polymers is far from being completed. New applications like in bioimaging keep emerging and even simple structural variations are still waiting to be explored. Surprisingly, not even dithioalkyl-substituted PPVs (S-PPVs) have been reported in the peer-reviewed literature, although the corresponding dialkoxy-substituted PPVs (O-PPVs) like MEH-PPV or MDMO-PPV are most frequently used and although thioalkyl substituents can improve the material properties significantly. We herein report the development of a highly efficient, scalable two-step synthesis of Gilch monomers for S-PPVs starting from low-cost 1,4-diiodobenzene. A low-temperature polymerization protocol has been developed for these monomers, affording high-molecular weight S-PPVs in excellent yields. The thermal, electrochemical, and photophysical properties of S-PPVs are reported to highlight the potential of these polymers. Furthermore, treatment with dimethyldioxirane is demonstrated to result in rapid conversion into sulfone-substituted PPVs (SO<sub>2</sub>-PPVs), introducing a route to high-molecular weight SO<sub>2</sub>-PPVs with exceptional stability and solid-state photoluminescence quantum yields of up to 0.46.

Antimicrobial and photophysical properties of chemically grafted ultra-high-molecular-weight polyethylene

2019 ◽  
Vol 96 ◽  
pp. 479-486 ◽  
Author(s):  
Monika Benkocká ◽  
Simona Lupínková ◽  
Tereza Knapová ◽  
Kateřina Kolářová ◽  
Jindřich Matoušek ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Photophysical Properties ◽  
Ultra High Molecular Weight

scholarly journals Polyhydroxymethylenes as Multifunctional High Molecular Weight Sugar Alcohols Tailored for 3D Printing and Medical Applications

2020 ◽  
Vol 221 (15) ◽  
pp. 2070035
Author(s):  
Benjamin Stolz ◽  
Florian Mönkemeyer ◽  
Markus Mader ◽  
Stanislaus Schmidt ◽  
Lukas Volk ◽  
...  
Keyword(s):  
Molecular Weight ◽  
3D Printing ◽  
High Molecular Weight ◽  
Medical Applications ◽  
Sugar Alcohols

3D Printing Latex: A Route to Complex Geometries of High Molecular Weight Polymers

2020 ◽  
Vol 12 (9) ◽  
pp. 10918-10928 ◽  
Author(s):  
Philip J. Scott ◽  
Viswanath Meenakshisundaram ◽  
Maruti Hegde ◽  
Christopher R. Kasprzak ◽  
Christopher R. Winkler ◽  
...  
Keyword(s):  
Molecular Weight ◽  
3D Printing ◽  
High Molecular Weight ◽  
Complex Geometries ◽  
High Molecular Weight Polymers

scholarly journals Effect of Adhesion on Mechanical and Tribological Properties of Glass Fiber Composites, Based on Ultra-High Molecular Weight Polyethylene Powders with Various Initial Particle Sizes

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1602 ◽  
Author(s):  
Sergey V. Panin ◽  
Lyudmila A. Kornienko ◽  
Qitao Huang ◽  
Dmitry G. Buslovich ◽  
Svetlana A. Bochkareva ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Glass Fiber ◽  
High Molecular Weight ◽  
Tribological Properties ◽  
Glass Fibers ◽  
Operating Conditions ◽  
Powder Size ◽  
Mechanical And Tribological Properties ◽  
Polymer Powder ◽  
Ultra High Molecular Weight

The aim of this study was to assess the effect of adhesion between the non-polar, ultra-high molecular weight polyethylene (UHMWPE) matrix and the glass fiber fillers of various lengths treated with the commercially available “KH-550” agent, on the mechanical and tribological properties of the UHMWPE-based composites. The motivation was to find the optimal compositions of the polymer composite, for the compression sintering manufacturing of lining plates for the protection of marine venders and construction vehicles, as well as transport equipment. It was shown that the initial powder size at equal molecular weight determined the distribution patterns of the glass fibers in the matrix, and, as a consequence, the mechanical and tribological properties of the composites. Based on the obtained experimental data and the results of the calculation by a developed computer algorithm, control parameters were determined to give practical recommendations (polymer powder size and glass fiber length), for the production of the UHMWPE-composites having specified mechanical and tribological characteristics. The “GUR4022 + 10% LGF” composite, loaded with the chopped 3 mm glass fibers treated with the “KH-550”, was recommended for severe operating conditions (high loads, including impact and abrasive wear). For mild operating conditions (including cases when the silane coupling agent could not be used), the “GUR2122 + 10% MGF” and “GUR2122 + 10% LGF” composites, based on the fine UHMWPE powder, were recommended. However, the cost and technological efficiency of the filler (flowability, dispersibility) and polymer powder processing should be taken into account, in addition to the specified mechanical and tribological properties.

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