“All-in-One” Thixotropic Polysiloxane Pastes for UV-Activated Room Temperature Hydrosilylation Cross-Linking in Additive Manufacturing

2021 ◽  
Vol 54 (4) ◽  
pp. 1715-1724
Author(s):  
James Beach ◽  
Shane Mann ◽  
Charles Ault ◽  
Dragana Radojcic ◽  
Xianmei Wan ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Room Temperature ◽  
Cross Linking

scholarly journals Transformation Between 2D and 3D Covalent Organic Frameworks via Reversible [2+2] Cycloaddition

2020 ◽  
Author(s):  
Thaksen Jadhav ◽  
Yuan Fang ◽  
Cheng-Hao Liu ◽  
Afshin Dadvand ◽  
Ehsan Hamzehpoor ◽  
...  
Keyword(s):  
Band Structure ◽  
Absorption Edge ◽  
Room Temperature ◽  
Three Dimensional ◽  
Cross Linking ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Doping Behavior ◽  
2D Polymers ◽  
2D And 3D

We report the first transformation between crystalline vinylene-linked two-dimensional (2D) polymers and crystalline cyclobutane-linked three-dimensional (3D) polymers. Specifically, absorption-edge irradiation of the 2D poly(arylenevinylene) covalent organic frameworks (COFs) results in topological [2+2] cycloaddition cross-linking the π-stacked layers in 3D COFs. The reaction is reversible and heating to 200°C leads to a cycloreversion while retaining the COF crystallinity. The resulting difference in connectivity is manifested in the change of mechanical and electronic properties, including exfoliation, blue-shifted UV-Vis absorption, altered luminescence, modified band structure and different acid-doping behavior. The Li-impregnated 2D and 3D COFs show a significant ion conductivity of 1.8×10<sup>−4</sup> S/cm and 3.5×10<sup>−5</sup> S/cm, respectively. Even higher room temperature proton conductivity of 1.7×10<sup>-2</sup> S/cm and 2.2×10<sup>-3</sup> S/cm was found for H<sub>2</sub>SO<sub>4</sub>-treated 2D and 3D COFs, respectively.

PROPERTIES OF WATER-SWELLABLE COMPOUNDS BASED ON NITRILE RUBBER WITH VARIED ACRYLONITRILE CONTENT

2021 ◽  
Author(s):  
M. A. Vaniev ◽  
S. S. Lopatina ◽  
N. V. Sychev ◽  
Y. Y. Savchenko ◽  
A. D. Bruk ◽  
...  
Keyword(s):  
Room Temperature ◽  
Mineral Content ◽  
Oil And Gas ◽  
Gas Production ◽  
Nitrile Rubber ◽  
Influential Factor ◽  
Cross Linking ◽  
Group Level ◽  
Oil And Gas Production ◽  
Swelling Rate

ABSTRACT This article examines the development of water-swellable rubbers for oil and gas production packer equipment. The object of the investigation is to document the effect of rubber's acrylonitrile content on the swelling of the elastomers modified with sodium-carboxymethyl cellulose and a copolymer of acrylamide and potassium acrylate. After testing the samples at room temperature, the most influential factor in a material's swelling was discovered to be the mineral content in the liquids imitating well fluids. NBR polarity stemming from the inherent CN-group level was not explicitly detected to affect the swelling rate and maximum ratio under the described conditions of the experiment. It was determined that in sodium chloride aqueous solutions with concentrations from 3 to 22%, swelling of nitrile rubber mostly depends on its cross-linking degree.

Rhodium(I)-catalysed cross-linking of polysiloxanes conducted at room temperature

2019 ◽  
Vol 372 ◽  
pp. 193-200 ◽  
Author(s):  
Mikhail V. Dobrynin ◽  
Carla Pretorius ◽  
Dumisani V. Kama ◽  
Andreas Roodt ◽  
Vadim P. Boyarskiy ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cross Linking

scholarly journals Synthesis and Characterization of Chemically Cross-Linked CMC/Acrylamide Hydrogels

2020 ◽  
Vol 32 (5) ◽  
pp. 1109-1115
Author(s):  
Shivakumara Lachakkal Rudrappa ◽  
Sudhir Ramaswamy Iliger ◽  
Demappa Thippaiah
Keyword(s):  
Room Temperature ◽  
Aluminum Sulfate ◽  
Ammonium Persulfate ◽  
Sem Analysis ◽  
Cross Linking ◽  
Swelling Behaviour ◽  
Buffer Solutions ◽  
Aluminium Sulfate ◽  
Chemical Cross Linking

Carboxymethyl cellulose/poly(acrylamide) (CMC/Amm) hydrogels were synthesized by the chemical cross-linking method. Ammonium persulfate used as an initiator, while aluminium sulfate used as a cross-linking agent. The structure and morphology of the hydrogels were characterized by FTIR and scanning electron microscopy (SEM) analysis. The swelling behaviour of the hydrogels can be studied by using acids (CH3COOH, HCl and HClO4) and also in the pH of the buffer solutions at different temperature (room temperature, 30 and 37 ºC) was studied. Swelling of hydrogels increased with an increase in the concentration of aluminum sulfate up to 20 %, above 20 % it has found to be decreased. The effect of four series of cationic different concentrated salt solutions on the swelling had found to be the following order K+ > Na+ > Ca2+ > Mg2+.

scholarly journals Cross-linking of polytetrafluoroethylene during room-temperature irradiation

2009 ◽  
Vol 94 (9) ◽  
pp. 1533-1541 ◽  
Author(s):  
David L. Pugmire ◽  
Christopher J. Wetteland ◽  
Wanda S. Duncan ◽  
Rollin E. Lakis ◽  
Daniel S. Schwartz
Keyword(s):  
Room Temperature ◽  
Cross Linking ◽  
Temperature Irradiation

Conductivities of Room Temperature Molten Salts Containing ZnCl2, Measured by a Computerized Direct Current Method

2002 ◽  
Vol 57 (3-4) ◽  
pp. 129-135
Author(s):  
Hsin-Yi Hsu ◽  
Chao-Chen Yang
Keyword(s):  
Activation Energy ◽  
Direct Current ◽  
Molten Salts ◽  
Room Temperature ◽  
Current Method ◽  
Cross Linking ◽  
Infra Red ◽  
Different Temperatures ◽  
The Stability ◽  
Benzyltriethylammonium Chloride

The conductivities of the binary room-temperature molten salt (RTMS) systems ZnCl2-N-nbutylpyridinium chloride (BPC), ZnCl2 -1-ethyl-3-methylimidazolium chloride (EMIC) and ZnCl2 - benzyltriethylammonium chloride (BTEAC) have been measured at different temperatures and compositions by a d.c. four-probes method. The conductivities of the three RTMS are in the order ZnCl2-EMIC > ZnCl2-BPC > ZnCl2-BTEAC. In ZnCl2-BPC the conductivity at 70 to 150 °C, is maximal for 40 mol% ZnCl2. In ZnCl2 - EMIC, the conductivity below 130 °C is almost constant for 30 to 50 mol% ZnCl2 and has the lowest activation energy 25.21 kJ/mol. For these two systems, the conductivities decrease rapidly beyond 50 mol% ZnCl2 owing to the rapid increase in cross-linking and resultant tightening of the polyelectrolyte structure. As to the ZnCl2-BTEAC system, the conductivities at 110 - 150 °C decrease slowly for 30 - 60 mol% ZnCl2. The conductivities of the ZnCl2-EMICmelt are compared with those of the AlCl3-EMIC melt previously studied. The stability of the ZnCl2-EMIC melt system is explored by the effect of the environment on the conductivity and the Far Transmission Infra Red (FTIR) spectrum. It reveals that the effect is slight, and that the ZnCl2-EMIC melt may be classified as stable.

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