scholarly journals Where ppm Quantities of Silsesquioxanes Make a Difference—Silanes and Cage Siloxanes as TiO2 Dispersants and Stabilizers for Pigmented Epoxy Resins

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 494
Author(s):  
Dariusz Brząkalski ◽  
Robert E. Przekop ◽  
Miłosz Frydrych ◽  
Daria Pakuła ◽  
Marta Dobrosielska ◽  
...  

In this work, silsesquioxane and spherosilicate compounds were assessed as novel organosilicon coupling agents for surface modification of TiO2 in a green process, and compared with their conventional silane counterparts. The surface-treated TiO2 particles were then applied in preparation of epoxy (EP) composites and the aspects of pigment dispersion, suspension stability, hiding power, as well as the composite mechanical and thermal properties were discussed. The studied compounds loading was between 0.005–0.015% (50–150 ppm) in respect to the bulk composite mass and resulted in increase of suspension stability and hiding power by over an order of magnitude. It was found that these compounds may be an effective alternative for silane coupling agents, yet due to their low cost and simplicity of production and manipulation, silanes and siloxanes are still the most straight-forward options available. Nonetheless, the obtained findings might encourage tuning of silsesquioxane compounds structure and probably process itself if implementation of these novel organosilicon compounds as surface treatment agents is sought for special applications, e.g., high performance coating systems.

2013 ◽  
Vol 849 ◽  
pp. 302-309
Author(s):  
Yun Xu ◽  
Xin Hua Zhu ◽  
Yu Wang

With rapid development of micro fabrication technology, the performance of MIMU has gradually improved. The MIMU introduced in this paper is based on the silicon micro machined gyroscope of type MSG7000D and accelerometer of type MSA6000. The volume of it is 3×3×3cm3, the mass is 68.5g and the power consumption is less than 1w. The experimental result shows that the bias stability of the gyroscope and accelerometer for each axis of the designed MIMU is less than 10°/h and 0.5mg respectively. For the non orthogonality in three axes of the structure, MIMU needs to be calibrated. After calibration, the measurement accuracy has improved by an order of magnitude. The designed MIMU can satisfy the requirement of high performance, low cost, light weight and small size for strap-down navigation system, thus it can be widely applied not only to the field of vehicles integrated navigation, attitude measurement but also to the fields of personal goods such as mobile, game consoles and so on.


NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850133 ◽  
Author(s):  
Ling Weng ◽  
HeBing Wang ◽  
Xiaorui Zhang ◽  
Lizhu Liu ◽  
Hexin Zhang

The hexagonal boron nitride nanosheets (BN) were firstly treated by silane coupling agents 3-aminopropyltriethoxysilane (KH550) and 3-glycidoxypropyl-trimethoxysilane (KH560) to introduce some amino and epoxy (EP) groups on the BN surface. These modified BN nanosheets were incorporated into an EP matrix to prepare BN@KH560/EP composites with excellent thermal conductivity and electrical insulation properties. Results showed that the thermal conductivity of BN@KH560/EP composite with 20[Formula: see text]vol% BN dosage was found to be 0.442[Formula: see text]W/(m[Formula: see text]K), which was 81% higher than that of pure EP resin. Both BN/EP composites treated by KH550 and KH560 showed rather good electrical insulation properties, although the dielectric constant of BN@KH550/EP composites were slightly higher than BN@KH560/EP composites. Moreover, BN@KH560/EP composites also showed better thermal and mechanical properties than that of BN@KH550/EP composites.


2013 ◽  
Vol 690-693 ◽  
pp. 1483-1489 ◽  
Author(s):  
You Lin Pan ◽  
Barry Arkles ◽  
James Kendenburg

Four different synthetic methods for preparation of aromatic sialnes have been developed and the hydrosilylation route has been proved to be one as the most commercially significant. A series of specialty aryl silanes have been synthesized for the potential applications of high performance and high temperature as silane coupling agents. The thermal stabilities of the bridged aromatic silanes have been examined using thermal gravimetric analysis (TGA) and compared against the gamma-substituted alkylsilanes and phenyltrimethoxysilane. These materials have greater thermal stability than the gamma-substituted, but marginally lower than phenyltrimethoxysilane.


1993 ◽  
Vol 323 ◽  
Author(s):  
P. H. Townsend ◽  
D. Schmidt ◽  
T. M. Stokich ◽  
S. Kisting ◽  
D. C. Burdeaux ◽  
...  

AbstractThis work examines the adhesion of coatings derived from divinylsiloxane bisbenzocyclobutene, mixed stereo and positional isomers of 1,3-bis(2-bicyclo[4.2.0]octa-1,3,5-trien-3-ylethenyl)-1,1,3,3-tetramethyl disiloxane (CAS 117732–87–3), on oxidized silicon substrates treated with silane coupling agents.This material, commercially available as Cyclotene™ 3022, can be used in the construction of high performance electronic circuits, such as multichip modules. Silane coupling agents examined in this study were 3-aminopropyltriethoxysilane (CAS 01760-24-3)(APTES)(, vinyltriethoxysilane (CAS 00078–08–0)(VTES), and 3-methacryloxypropyl trimethoxysilane (CAS 02530–85–0) (MOP-TMS).Measurement of the interfacial adhesion was performed using microindentation. Bond strengths obtained by this method exceed 200 MPa for the most effective coupling agents. However, these high bond strengths were not found to correlate with acceptable adhesive performance in all cases. In addition to the choice and preparation of the coupling agent, process related chemical exposure has been found to be a key element in the observed adhesive performance. The effect of the cure schedule for the thermoset coating has also been found to be a controlling factor. A short cycle test vehicle was developed consisting of a single 20 gIm polymer layer etched with anisotropic sidewalls. This test vehicle was used to evaluate the efficacy of the coupling agents during process exposures and subsequent thermal shock testing. A solution of MOP-TMS pre-hydrolyzed in methanol was found to produce the most reliable interface with high bond strength.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 296
Author(s):  
Wenzhe Zhao ◽  
Le An ◽  
Shujuan Wang

Epoxy-anhydride resins are widely used in engineering fields due to their excellent performance. However, the insolubility and infusibility make the recycling of epoxy resins challenging. The development of degradable epoxy resins with stable covalent networks provides an efficient solution to the recycling of thermosets. In this paper, 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) is incorporated into the epoxy-glutaric anhydride (GA) system to prepare high-performance epoxy resins that can be recycled below 200 °C at ordinary pressure via ethylene glycol (EG) participated transesterification. The tertiary amine groups in DMP-30 can catalyze the curing reaction of epoxy and anhydride, as well as the transesterification between ester bonds and alcoholic hydroxyl groups. Compared with early recyclable anhydride-cured epoxy resins, the preparation and recycling of diglycidyl ether of bisphenol A (DGEBA)/GA/DMP-30 systems do not need any special catalysts such as TBD, Zn(Ac)2, etc., which are usually expensive, toxic, and have poor compatibility with other compounds. The resulting resins have glass transition temperatures and strengths similar to those of conventional epoxy resins. The influences of GA content, DMP-30 content, and temperature on the dissolution rate were studied. The decomposed epoxy oligomer (DEO) is further used as a reaction ingredient to prepare new resins. It is found that the DEO can improve the toughness of epoxy resins significantly. This work provides a simple method to prepare readily recyclable epoxy resins, which is of low-cost and easy to implement.


2020 ◽  
Vol 117 (11) ◽  
pp. 5588-5594 ◽  
Author(s):  
Prateek Hundekar ◽  
Swastik Basu ◽  
Xiulin Fan ◽  
Lu Li ◽  
Anthony Yoshimura ◽  
...  

The use of potassium (K) metal anodes could result in high-performance K-ion batteries that offer a sustainable and low-cost alternative to lithium (Li)-ion technology. However, formation of dendrites on such K-metal surfaces is inevitable, which prevents their utilization. Here, we report that K dendrites can be healed in situ in a K-metal battery. The healing is triggered by current-controlled, self-heating at the electrolyte/dendrite interface, which causes migration of surface atoms away from the dendrite tips, thereby smoothening the dendritic surface. We discover that this process is strikingly more efficient for K as compared to Li metal. We show that the reason for this is the far greater mobility of surface atoms in K relative to Li metal, which enables dendrite healing to take place at an order-of-magnitude lower current density. We demonstrate that the K-metal anode can be coupled with a potassium cobalt oxide cathode to achieve dendrite healing in a practical full-cell device.


Author(s):  
Swarn Jha ◽  
Yan Chen ◽  
Rick Wang ◽  
Mohamed Gharib ◽  
Hong Liang

Abstract High performance coatings are needed for downhole drilling applications. The main challenge in developing such coatings is to impart desirable surface characteristics such as low friction, high wear and corrosion resistance, while retaining structural integrity and consistency. Most coatings do not sustain the conditions in harsh environments resulting in failure and safety hazards. In this research, we designed high temperature coatings with integration of components that display wear resistance. After synthesis, they exhibited promising lubrication performance. Specifically, a simple and low-cost method was developed that can process the coating consisting high-temperature ceramics such as BN, SiC. Hybridizing graphite and α-zirconium phosphate as friction modifiers ideal for use with metals, alloys and ceramics, this coating is durable in a wide range of temperatures. Experimental results showed that the friction coefficient obtained for our coating was 0.17 as against the 0.50 value obtained for steel on steel sliding contact. In this work, we detail about the composition, microstructure, and tribological evaluation of the coatings tailored for drilling applications.


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