scholarly journals Multi-Fold Enhancement in Compressive Properties of Polystyrene Foam Using Pre-delaminated Stearate Functionalized Layer Double Hydroxides

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Emmanuel O. Ogunsona ◽  
Koffi L. Dagnon ◽  
Nandika Anne D'Souza
Keyword(s):  
Surface Area ◽  
Supercritical Co2 ◽  
Hydrophobic Interactions ◽  
High Surface ◽  
High Surface Area ◽  
Bubble Nucleation ◽  
Environmentally Benign ◽  
Compressive Properties ◽  
Layer Double Hydroxides ◽  
Double Hydroxides

Developing an environmentally benign styrene foam is a critical environmental need. Supercritical CO2 use in foams has proven to be a valuable path. Adding fillers to increase bubble nucleation has been pursued concurrently. A prominent filler used is high surface area fillers, such as smectic clays. However, all studies to date show a limit of 152% in compressive moduli and 260% in the compressive stress. The values, even with such gains, limit structural application. A seminal work in 1987 by Suh and Cotton proved that carbonyl linkages in calcium carbonates and CO2 interact and impact nucleation efficiency and performance in supercritical CO2 foams. In this paper, a high surface area clay (layer double hydroxides) which begins in an exfoliated state, then functionalized with a long chain alkyl carboxylate (stearic acid) is synthesized. The result is a remarkable multi-fold improvement to the compressive properties in comparison to polystyrene (PS); a 268% and 512% increase in compressive modulus and strength, respectively. Using a pre-delaminated approach, the higher surface area was achieved in the clays. The presence of the stearate improved the interactions between the clay galleries and PS through hydrophobic-hydrophobic interactions. The glass transition temperature of the nanocomposites was observed to shift to higher values after foaming. The results point to a new path to increase performance using a pre-delaminated clay with functional groups for environmentally benign foams.

Synthesis and Characterization of High Surface Area Flower-Like Ca-Containing Layered Double Hydroxides Mg3–xCax Al1–NO3

2013 ◽  
Vol 5 (4) ◽  
pp. 411-420 ◽  
Author(s):  
Qiang Wang ◽  
Yanshan Gao ◽  
Zhang Zhang ◽  
Linhai Duan ◽  
Ahmad Umar ◽  
...  
Keyword(s):  
Surface Area ◽  
Layered Double Hydroxides ◽  
High Surface ◽  
High Surface Area ◽  
Synthesis And Characterization ◽  
Double Hydroxides

Synthesis of high surface area MgAl2O4 spinel as catalyst support via layered double hydroxides-containing precursor

2016 ◽  
Vol 132-133 ◽  
pp. 243-250 ◽  
Author(s):  
Dalin Li ◽  
Miaomiao Lu ◽  
Yunbing Cai ◽  
Yanning Cao ◽  
Yingying Zhan ◽  
...  
Keyword(s):  
Surface Area ◽  
Layered Double Hydroxides ◽  
High Surface ◽  
Catalyst Support ◽  
High Surface Area ◽  
Mgal2o4 Spinel ◽  
Double Hydroxides

scholarly journals Niobium oxide prepared through a novel supercritical-CO2-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline

2019 ◽  
Vol 21 (21) ◽  
pp. 5852-5864 ◽  
Author(s):  
Yehan Tao ◽  
Bhawan Singh ◽  
Vanshika Jindal ◽  
Zhenchen Tang ◽  
Paolo P. Pescarmona
Keyword(s):  
High Activity ◽  
Surface Area ◽  
Heterogeneous Catalyst ◽  
Oxidative Coupling ◽  
Supercritical Co2 ◽  
Niobium Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Highly Active

High-surface area Nb2O5 nanoparticles synthesised by a novel supercritical-CO2-assisted method displayed extremely high activity as heterogeneous catalyst in the oxidative coupling of aniline to azoxybenzene using the green oxidant H2O2.

Synthesis and characterisation of aqueous miscible organic-layered double hydroxides

2014 ◽  
Vol 2 (36) ◽  
pp. 15102-15110 ◽  
Author(s):  
Chunping Chen ◽  
Miaosen Yang ◽  
Qiang Wang ◽  
Jean-Charles Buffet ◽  
Dermot O'Hare
Keyword(s):  
Surface Area ◽  
Layered Double Hydroxide ◽  
Layered Double Hydroxides ◽  
High Surface ◽  
High Surface Area ◽  
New Family ◽  
Double Hydroxide ◽  
Double Hydroxides

We report the synthesis and characterisation of a new family of high surface area and dispersible layered double hydroxides entitled Aqueous Miscible Organic Layered Double Hydroxide (AMO-LDH).

scholarly journals Water adsorbancy of high surface area layered double hydroxides (AMO-LDHs)

RSC Advances ◽  
2018 ◽  
Vol 8 (60) ◽  
pp. 34650-34655 ◽  
Author(s):  
Chunping Chen ◽  
Kanittika Ruengkajorn ◽  
Jean-Charles Buffet ◽  
Dermot O'Hare
Keyword(s):  
Surface Modification ◽  
Relative Humidity ◽  
Surface Area ◽  
Layered Double Hydroxides ◽  
High Surface ◽  
High Surface Area ◽  
High Water ◽  
Acid Base ◽  
Water Inhibition ◽  
Double Hydroxides

Water adsorbancy of high surface area layered double hydroxides in different relative humidity was investigated. High water inhibition can be achieved via surface modification of LDHs with stearic acid via acid–base reaction.

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Generation ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Efficiency ◽  
Carbon Cloth ◽  
Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

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