scholarly journals Porous Materials Based on Poly(methylvinylsiloxane) Cross-Linked with 1,3,5,7-Tetramethylcyclotetrasiloxane in High Internal Phase Emulsion as Precursors to Si-C-O and Si-C-O/Pd Ceramics

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5661
Author(s):  
Jan Mrówka ◽  
Janusz Partyka ◽  
Magdalena Hasik

Polysiloxane networks were prepared by hydrosilylation of poly(methylvinylsiloxane) (V3 polymer) with 1,3,5,7-tetramethylcyclotetrasiloxane (D4H) at various Si-Vinyl: Si-H groups molar ratios in water-in-oil high internal phase emulsion (HIPE). Curing the emulsions followed by removal of water led to foamed cross-linked polysiloxane systems differing in the cross-linking degrees, as well as residual Si-H and Si-Vinyl group concentrations. Treatment of thus obtained materials in Pd(OAc)2 solution in tetrahydrofuran resulted in the formation of porous palladium/polymer nanocomposites with different Pd contents (1.09–1.70 wt %). Conducted investigations showed that pyrolysis of the studied materials at 1000 °C in argon atmosphere leads to porous Si-C-O and Si-C-O/Pd ceramics containing amorphous carbon and graphitic phases. Thermogravimetric (TG) analysis of the starting cross-linked polymer materials and those containing Pd nanoparticles revealed that the presence of palladium deteriorates thermal stability and decreases ceramic yields of preceramic networks. The extent of this effect depends on polymer cross-linking density in the system.

Polymer ◽  
2014 ◽  
Vol 55 (1) ◽  
pp. 395-402 ◽  
Author(s):  
Ling L. Ching Wong ◽  
Suelen Barg ◽  
Angelika Menner ◽  
Paula do Vale Pereira ◽  
Goki Eda ◽  
...  

2020 ◽  
Vol 138 (11) ◽  
pp. 50019
Author(s):  
Xuehui Gong ◽  
Boran Zhao ◽  
Ica Manas‐Zloczower ◽  
Donald L. Feke

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 721 ◽  
Author(s):  
Jorge A. Ramírez-Gómez ◽  
Javier Illescas ◽  
María del Carmen Díaz-Nava ◽  
Claudia Muro-Urista ◽  
Sonia Martínez-Gallegos ◽  
...  

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ.


2019 ◽  
Vol 10 (9) ◽  
pp. 5446-5460 ◽  
Author(s):  
Chi Yan ◽  
David Julian McClements ◽  
Liqiang Zou ◽  
Wei Liu

A high internal phase emulsion (HIPE) was firstly fabricated with octenyl succinic anhydride modified starch through simple shear dispersion.


2014 ◽  
Vol 884-885 ◽  
pp. 186-189 ◽  
Author(s):  
San Zhu ◽  
Xiao Gang Luo ◽  
Li Bin Ma ◽  
Ya Nan Xue ◽  
Ning Cai ◽  
...  

Novel composite resins with dual absorption properties of water and oil are prepared by the polymerization of high internal phase emulsion (HIPEs) with n-butyl methacrylate as the external phase monomer and acrylamide as the internal phase monomer. The subsequent polymerization leads to the formation of water and oil dual-absorption composite resins. The morphology of porous structure and microcosmic phase separation after water/oil uptake is observed by scanning electron microscopy (SEM). The water and oil absorbency strongly depend on composition. The composites with saturated water uptake could absorb the chloroform again but cant absorb water if saturated with chloroform first. And the resins exhibit great reusability, keeping almost constant absorbency. The present methodology could be a potential approach to obtain amphiphilic composites, which possess potential applications in the bioengineering, medical and industrial fields.


2015 ◽  
Vol 3 (20) ◽  
pp. 4118-4122 ◽  
Author(s):  
Bernice H. L. Oh ◽  
Alexander Bismarck ◽  
Mary B. Chan-Park

By varying the oligolysine units of chitosan-graft-oligoNIPAM-graft-oligolysine, high internal phase emulsions of different droplet sizes can be stabilized which can subsequently serve as template for macroporous polymers.


2021 ◽  
pp. 131305
Author(s):  
Yingwei Liu ◽  
Wan Jun Lee ◽  
Chin Ping Tan ◽  
Oi Ming Lai ◽  
Yong Wang ◽  
...  

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