Synthesis, Characterization, Modeling and Applications of Functional Porous Materials: Poster Session
Program Organizers: Lan Li, Boise State University; Winnie Wong-Ng, National Institute of Standards and Technology (NIST); Kevin Huang, University of South Carolina
Tuesday 12:00 PM
October 1, 2019
Room: Exhibit Hall CD
Location: Oregon Convention Center
P2-77: A Novel Styrene-assisted Monomer Route for Polymer Derived Macroporous SiBCN Ceramic Monolith: Xuan Cheng1; Lujiao Yang1; Ying Zhang1; 1Xiamen University
A styrene-assisted monomer route was developed to prepare polymer derived macroporous silicoboron carbonitride (SiBCN) ceramic monolith. The structural evolution and pore formation were studied for the precursor by reacting bis(trimethylsilyl)carbodiimide with tris(dichloromethylsilylethyl)borane and the polymer derived ceramic. The results are compared with those of precursor and ceramic prepared without using styrene. It was found that the introduction of styrene into the monomers seemed to slow down the chemical reaction through a dilution-like behavior, forming a styrene-monomers-mixed polymer precursor. Accordingly, the SiBCN ceramic monolith with the major average pore sizes of 20.9/58.1 m and the total porosity of 74% was obtained upon the pyrolysis process after the vacuum purification of by-product from monomers reaction and polystyrene produced by styrene polymerization with the heat treatment.
P2-78: An Atomic Force Microscopic Investigation on Single Secondary Particle of Silica Aerogel Monolith: Xiaoyong He1; Xuan Cheng1; Ying Zhang1; 1Xiamen University
An atomic force microscopic study was performed to determine elastic modulus of single secondary particle on silica aerogel monolith. Based on the displacement-applied load curves of single crystal silicon wafer, the initial contact point of the tip on the sample could be determined. By substituting the secondary particles for the silicon wafer, the depth-applied load curves were obtained by analyzing the corresponding displacement-applied load curves. The elastic modulus is calculated to be 6.2 GPa for the porous silica aerogel by fitting the elastic part of depth-applied load curves with the Hertzian equation, which is ten times smaller than 72.5 GPa of the fused silica due mainly to the agglomerated structure formed by the primary particles. The correlation between the mechanical response of the secondary particles and compressive strain-stress behavior of silica aerogel monolith is discussed.
P2-79: Corrosion Studies of Open Cell Aluminum Foams in Simulated Marine Environments: Ho Lun Chan1; Kevin Guo1; Adam Teoh1; Rogine Gomez1; Vilupanur Ravi1; 1Cal Poly Pomona
Aluminum foams are used in aircraft components, e.g. landing gear energy absorbers, breather plugs, etc., because of their high impact absorption capability, low density, and cost-effectiveness. These materials can be subjected to chloride corrosion in marine environments, with the potential to lower the service life of these components. In this project, the microstructure and mechanical strength of aluminum foams pre-and post-corrosion were examined. The corrosion behavior of UNS A96101-T6 aluminum foams was studied as a function of pore density. Corrosion tests were performed by immersing aluminum foams in simulated seawater (ASTM G31) and also by exposing them to salt spray environments (ASTM B117) for periods of time ranging from 1 to 100 hours. The microstructures of the test coupons were subsequently characterized using scanning electron microscopy (SEM). Compression tests (ISO 13314) were conducted on pre-and post-corrosion coupons. The results of these studies will be presented and discussed.
P2-80: Epoxy Foam based Composites for Anechoic Chamber Application: From Elaboration to a Dielectric Characterization: Chloé Méjean1; Ratiba Benzerga1; Hanadi Breiss1; Aicha El Assal1; Ala Sharaiha1; 1University Rennes, IETR
Absorbers, usually used in anechoic chambers, are made of polyurethane foam impregnated with fine carbon particles. They have high absorption performance but suffer from their mechanical properties, that limits the realization of new complex shape (to optimize their performance), and from the premature aging due to the escape of particles (which are dangerous for human health). In our team, we have elaborated a new absorbing material based on long carbon fibers associated with rigid epoxy foam, in order to respond to both failures of the commercial material mentioned above. For this study, different dispersions techniques of the fibers have been used and the influence of the percentage and the length of carbon fibers as well as the dispersion techniques on the dielectric properties of the elaborated composites will be presented. The measurement of our prototype that will be presented and discussed, shows very promising result, compared to the commercial material.
P2-81: Foam Composites for Planar Absorber Application: Aicha El Assal1; Ratiba Benzerga1; Ala Sharaiha1; Ali Harmouch1; Akil Jrad1; 1University Rennes, IETR
Today, absorbents are more and more used for different applications to reduce, for example, the electromagnetic interferences and the radar cross section. For this study, we propose to realize a planar absorbent using several layers (five layers with a total thickness of 125 mm) of epoxy foams loaded with long carbon fibers. Different lengths and percentages of carbon fibers are used. A numerical simulation, study using CST software studio, leads to choose the composition of each layer (length and concentration of carbon fibers) as well as its thickness, based on the principle of impedance matching. The measurement of the achieved prototype was compared to the simulation where a reflection coefficient less than -15 dB which means 96% of absorption is obtained.
P2-82: Inorganic Foam Composites for Absorption in X Band Frequency Range: Ratiba Benzerga1; Vincent Laur2; Ronan Lebullenger3; Laurent Le Gendre1; Ala Sharaiha1; 1University of Rennes, IETR; 2LabSTICC; 3ISCR
Today, recycling has become a common practice and a full component of the economy particularly in the glass industry. This study discusses the use of recycled industrial glass as a new inorganic absorber for microwave application. Two types of waste glass (Cathode Ray Tube and Soda-Lime Silicate) and various foaming agents are used to prepare the glass foams. The dielectric characterization shows that the density of the foamed material and the type of used foaming agent influence the dielectric properties; the use of carbon particles as foaming agent leads to lossy materials. Simulation of pyramidal absorber, made with carbon as foaming agent, was conducted to estimate the absorption capacity of the foam. The reflection loss was greater than -20 dB in the X-band frequency range. The high losses associated with the thermal stability of inorganic foams position these materials as potential high power load in frequency devices.
P2-84: Rapid, Additive Synthesis of Functional Metal-Organic Framework Thin Films: Yujing Zhang1; Chih-Hung Chang1; 1Oregon State University
Metal-organic frameworks (MOFs) are a class of highly-ordered nanoporous crystals that possess a designable framework and unique chemical versatility. MOF thin films are particularly suited in nanotechnology-enabling applications such as optoelectronics, catalytic coatings, chemical sensors, etc. Most MOF thin films are realized by immersing selected substrates, which are usually porous or decorated with special surface anchors, in precursor solutions before one-step batch reaction or layer-by-layer liquid epitaxy. Herein, we introduce a simple, fast, and cost-effective synthesis protocol for the fabrication of MOF thin films in an additive manner. Two different types of MOF thin films were facilely fabricated within minutes, showing good uniformity and strong adhesion to bare SiO2 surfaces. The functionality of resulting MOF thin films for gas adsorption was tested for CO2, demonstrating these films’ potential for CO2 gas sensing. In conclusion, this work demonstrates an innovative, additive approach to realize rapid, large-scale fabrication of MOF thin films.
P2-85: Time-Domain Thermoreflectance Investigation of the Thermal Conductivity for Amorphous Nano-porous Organo-Silicate Thin Films: Hari Harikrishna1; Scott Huxtable1; Ira Ben Shir2; Shifi Kababya2; Asher Schmidt2; David Gidley3; William Lanford4; Sean King5; 1Virginia Tech; 2Technion - Israel Institute of Technology; 3University of Michigan; 4University of Albany; 5Intel
We have investigated the influence of elemental composition, atomic structure, and nano-porosity on the thermal conductivity for a series of organo-silicate (SiOCH) thin film dielectrics. Time-domain thermoreflectance (TDTR) was specifically utilized to meaure thermal conductivity while the influence of elemental composition, mass density, network bond structure, percent porosity, pore size and pore interconnectivity were examined using a variety of techniques. Analytical models describing the dependence of thermal conductivity on mass density and volume % porosity were found to generally over-predict the experimentally measured thermal conductivity, but improved agreement was obtained when considering only the density of heat carrying network bonds experimentally measured by FTIR. However, the thermal conductivity results were found to be best described via a model proposed by Sumirat (J. Porous Mater. 9, 439 (2006)) which considers the effect of both the volume percent porosity and phonon scattering by nanometer sized pores.