Materials Science and Engineering Commons^™

Mechanical Behavior And Properties Of Repo4 Studied By Nanoindentation, Corinne Packard

Composites at Lake Louise (CALL 2015)

Rare-earth orthophosphates (REPO₄s) have been used in experimental fiber matrix composites and are known to deform via a variety of mechanisms including dislocation motion, fracture, twinning, and pressure-induced phase transformations. REPO₄ with RE in the range of Z=64-66 (Gd-Dy) are particularly interesting due to their proclivity for polymorphism and phase transformation. To date, the behavior of these materials has been briefly studied using nanoindentation; however, detailed analysis of the indentation curves is made difficult due to the large number of potential deformation mechanisms. This study analyzes the behavior of nanoindentation load-depth curves and mechanical properties collected from …

Ductile Organic Aerogels For Multifunctional Applications, Hongbing Lu

Composites at Lake Louise (CALL 2015)

Monolithic polyurea aerogels were prepared by controlling the relative isocyanate/water/catalyst (Et3N) ratio in acetone, acetonitrile, or DMSO to prevent precipitation, yielding polyurea (PUA) gels which can be subsequently dried to form highly porous (up to 98.6% v/v) aerogels over a very wide range of densities (0.016-0.55 g cm^-3). The method has been implemented successfully with several aliphatic and aromatic di and triisocyanates. Polyurea aerogels were then studied at the molecular level, the elementary nanoparticle level, and the microscopic level. Their porous structure was probed with N₂-sorption porosimetry. Despite that the nanomorphology varies with density from fibrous …

Thermal Expansion And Phase Transformation Behavior In The Rare-Earth Titanate System, Waltraud Kriven, Kevin Seymour

Composites at Lake Louise (CALL 2015)

The thermal expansion and phase transformation behavior in the rare-earth titanate system has not been well understood. Much of the previous work in this material system was performed ex situ and reveals little information about the thermal expansion, mechanisms behind this expansion, and the relationship between the orthorhombic and hexagonal phases with temperature.

In this paper, a unique method using a thermal image furnace and synchrotron radiation was employed to monitor crystallographic changes in this material system in situ to determine the thermal expansion tensor and describe the mechanism behind such behavior. In addition, this information was paired with insights …

Role Of Interfaces In Polymer Matrix Composites And Methodologies To Improve And Characterize Interfaces In Composites, B.K Khatiwada

Composites at Lake Louise (CALL 2015)

Interfaces in composite materials play disproportionate roles in the ultimate physical properties in systems where polymers are used. Generally, the adsorption of polymers on solid substrates changes the behavior of the polymers at the interface. These changes can be dramatic and have major effects on the mechanical and chemical properties of the composite materials. The distance scales over which these changes occur are small, even as small as 10 nm or less (often less than the unperturbed radius of the molecule) and it is difficult to use many standard techniques to study them. The focus of the work presented here …

Oxygen And Carbon Dioxide Separation Membranes Based On Mixed Conductors, Hitoshi Takamura

Composites at Lake Louise (CALL 2015)

Gas separation is one of the key technologies to improve the efficiency of combustion process, and to reduce the emission of global warming gases. By using pure or concentrated oxygen, flame temperature governing the Carnot efficiency and the concentration of CO₂ in exhaust gas can be raised. Among a number of oxygen separation techniques such as cryogenic separation, oxygen separation membranes based on mixed oxide-ion and electronic conductors have been attracting much attention because of its high selectivity (100% in principle) and the ease of integration into various combustion systems. Figure 1(a) shows how the oxygen separation membrane works; …

Mechanisms And Models For Sic Fiber Strength Changes After Oxidation In Air And Steam, Randall Hay

Composites at Lake Louise (CALL 2015)

The strengths of Hi-Nicalon^TM-S SiC fibers were measured after oxidation in wet air, dry air, and Si(OH)₄ saturated steam between 600° and 1400°C. Amorphous and crystalline SiO₂ scale thickness was measured by TEM. Deal-Grove kinetics for oxidation and Kolmogorov-Johnson-Mehl-Avrami kinetics for crystallization were determined. Fibers oxidized in steam much more rapidly than in dry or wet air. Hi-Nicalon^TM-S fibers were completely oxidized to crystalline SiO₂ after 100h at 1100°C. The corresponding scale thickness for dry air was 1.3 mm. Fiber strength changes after oxidation in dry and wet air were similar, but with …

Thermally Conductive Composites, Oren Regev

Composites at Lake Louise (CALL 2015)

The rapidly increasing device densities in electronics calls for efficient thermal management. If successfully exploited, graphene, which possesses extraordinary thermal properties, can be commercially utilized in polymer composites with ultrahigh thermal conductivity (TC). The total potential of graphene to enhance TC, however, is restricted by the large interfacial thermal resistance between the polymer-mediated graphene boundaries. We report a facile and scalable dispersion of commercially available graphene nano platelets (GnPs) in a polymer matrix, which forms composite with ultra-high TC of 12.4 W/mK (vs. 0.2 W/mK for neat polymer). This ultra-high TC is achieved by applying high compression forces during the …

Controlling The Interfacial Properties Of One-Dimensional Nanostructures, Kirk Ziegler

Composites at Lake Louise (CALL 2015)

The high surface area of nanomaterials dictates that the interface with their surroundings is important in determining their properties or functionality. For example, all atoms in single-walled carbon nanotubes (SWCNTs) exist on the surface and, therefore, have excellent sensing capabilities. The interface of SWCNTs with their surroundings is also important to their application in polymer composites, devices, drug delivery, bioimaging and biosensing. Understanding and ultimately controlling these surface layers is important because of its influence on dispersion, reactivity, adsorption of pollutants, and interaction with biological materials. SWCNT interfaces are often altered with surfactants to improve their dispersion in aqueous suspensions. …

Bio-Inspired Hybrid Nanocomposites In Single Crystalline Hosts: From Structure To Function, Boaz Pokroy

Composites at Lake Louise (CALL 2015)

Often crystals in nature exhibit fascinating mechanical, optical, magnetic and other characteristics. Such natural single crystals are very different than man-made crystals: they are in fact hybrid nanocomposites due to the incorporation of organic molecules within heir crystalline lattice and often reveal intricate shapes and morphologies rather than clear facets.

In this talk I will show that we can emulate these two specific features demonstrated by organisms so as to form new structural materials with new properties and characteristics.

I will show that we can grow inorganic single crystals in which different organic molecules are incorporated on a nanometer scale. …

Multilayer Nanocoatings Capable Of Separating Gases, Killing Bacteria And Stopping Fire, Jaime Grunlan

Composites at Lake Louise (CALL 2015)

Layer-by-layer (LbL) assembly is a conformal coating “platform” technology capable of imparting a multiplicity of functionalities on nearly any type of surface in a relatively environmentally friendly way. At its core, LbL is a solution deposition technique in which layers of cationic and anionic materials (e.g. nanoparticles, polymers and even biological molecules) are built up via electrostatic attractions in an alternating fashion, while controlling process variables such as pH, coating time, and concentration. Here we are producing nanocomposite multilayers (50 – 1000 nm thick), having 10 – 96 wt% clay, that are completely transparent and exhibit oxygen transmission rates below …

Hard/Soft Composited Materials For Stretchable Electronics, Hyun-Joong Chung, Xinda Li, Yi Chen

Composites at Lake Louise (CALL 2015)

Convergence between scientific disciplines creates myriads of new opportunities to the problems that traditional approaches have not provided the answers. For example, researches on materials engineering and nanofabrication can shed a light to the current challenges in clinical biomedical science. Specifically, this presentation describes how materials science is employed to solve fundamental and practical problems in the intimate integration of the state-of-art inorganic devices onto living organs or skins for biomedical research. [1]

Firstly, bioresorbable elastomers make a basic building block for tissue scaffolds for soft, moving organs (such as heart, blood vessels, and smooth muscles) and for substrate material …

Magnetically Assisted Assembly Of Bioinspired Composites, Tobias Niebel, Hortense Le Ferrand, Florian Bouville, André Studart

Composites at Lake Louise (CALL 2015)

Heterogeneous composites with intricate microstructures can be found widely in nature fulfilling the functional demands imposed by their environment. Reaching this level of intricacy in synthetic composites remains a challenge due to the lack of suitable and easily available processing tools. We present a new method to produce bioinspired composites with a broad variety of locally controlled composition, texture and shape using low magnetic fields. Nacre-like all-ceramic, polymer-ceramic and metal-ceramic composites with volume fractions of ceramic phase spanning from 40 to values as high as 95 vol% are achieved. By mixing magnetically responsive alumina microplatelets with ceramic nanoparticles, we can …

Mica Platelet-Reinforced, Geopolymer Composites, Patrick Keane

Composites at Lake Louise (CALL 2015)

The mica flakes were obtained from the Cogebi Company as phlogopite mica paper type Cobebi P160 containing no organic or inorganic binder. Mica can withstand temperatures in excess of 1000°C. Phlogopite, of composition (KMg₃(AlSi₃O₁₀)(OH)₂ is flame-retardant, non-flammable, does not give off fumes. It conducts very little heat, especially perpendicular to its strata. Natural mica has a dielectric strength greater than 25 kV/mm (625 V/mil), has good resistance to arcing and electrical erosion, and is permeable to microwaves. Mica has good compressive strength. It behaves well in the presence of tensile and bending stresses. …

Biologically Inspired And Impact-Resistant Composites, David Kisailus

Composites at Lake Louise (CALL 2015)

There is an increasing need for the development of multifunctional lightweight materials with high strength and toughness. Natural systems have evolved efficient strategies, exemplified in the biological tissues of numerous animal and plant species, to synthesize and construct composites from a limited selection of available starting materials that often exhibit exceptional mechanical properties that are similar, and frequently superior to, mechanical properties exhibited by many engineering materials. These biological systems have accomplished this feat by establishing controlled synthesis and hierarchical assembly of nano- to micro-scaled building blocks. This controlled synthesis and assembly require organic that is used to transport mineral …

Center For Bioplastics And Biocomposites: Bringing Industry And Universities Together To Develop New Biobased Products And Technologies, Michael Kessler

Composites at Lake Louise (CALL 2015)

The Center for Bioplastics and Biocomposites (CB2) is a NSF Industry & University Cooperative Research Center that brings together industry partners and university researchers who have a common interest in biobased plastics and composites. CB2 is developing the knowledge that will allow the production of high-value products from sustainable agricultural and forestry feedstocks that are compatible with current industrial manufacturing systems.

CB2 is focused on six research areas that will promote industry-wide acceptance of bioplastics and biocomposites and increase the use of sustainable materials: synthesis and compounding, processing, biocomposites, medical applications, biobased products, and modeling.

Companies, commodity boards, and other …

Atomistic Structures And Transport Phenomena At Interfaces In Lithium Battery Materials, Akihide Kuwabara

Composites at Lake Louise (CALL 2015)

Lithium-ion batteries (LIBs) are widely used in mobile devices. Increasingly they are also being scaled up for use as energy-storage devices in hybrid vehicles and fully electric ones. All-solid-state LIBs are expected to be one of the candidates as next generation LIBs because the LIBs can realize higher energy density and safety without liquid electrolytes. In these devices, the solid-solid interfaces, specifically those between electrodes and an electrolyte and grain boundaries within each component, are thought to strongly affect the battery performance. Despite their clear scientific and technical importance, however, so far, few studies have focused on the internal interfaces …

Designing Fire Safe Composites, Maude Jimenez

Composites at Lake Louise (CALL 2015)

Composites are increasingly used in transportation (railway, aircrafts,…) and their applications are more and more oriented toward structural parts. However the fire risk linked to the use of such organic materials has to be strongly reduced to keep this attractiveness and hence flame retardant solutions have to be used to fire proof them. A classical way to achieve fire performance is to incorporate fire retardants (FRs) in the bulk of the polymeric matrix of the composites at loading between 15 and 40wt%. However with such an approach, flammability properties of the composites will be achieved at the expense of their …

Stimuli Responsive Nanocomposites Based On Cellulose Nanocrystals, Sandra Camarero, Tobias Kuhnt, Christoph Weder

Composites at Lake Louise (CALL 2015)

Cellulose nanocrystals (CNCs) are high-aspect ratio, mechanically stiff fibers which can serve as both a bio-renewable reinforcing agent in nanocomposites, as well as a handle for adding stimuli responsiveness. CNCs can be extracted from a wide range of natural cellulosic materials, with characteristics such as crystal structure, crystallinity and aspect ratio fluctuate widely between sources. Here, we report small molecule functionalized cellulose prepared for sustained delivery in a variety of environments. Moieties attached to the surface of cellulose nanocrystals show that both irreversible and reversible changes can be induced by application of an external stimuli.

Moreover, we present the case …

Structural Composites From High Performance Bioepoxies, Daniel Schmidt

Composites at Lake Louise (CALL 2015)

The increased utilization of structural composites has had a significant and tangible impact on everyday life, enabling real progress in a broad range of application areas from transportation to wind energy to sporting goods. Unfortunately, however, the vast majority of these materials are petroleum derived, and tend to be difficult or impossible to truly recycle, with downcycling, landfilling or even incineration much more common. This represents both a major waste and a lost opportunity.

In this talk, an overview is provided of our efforts to date aimed at addressing these issues, as well as some of our most recent results …

Role Of Molecular Interactions On The Mechanics Of Nanocomposites, Dinesh Katti, Kalpana Katti

Composites at Lake Louise (CALL 2015)

Nanocomposite materials are well characterized using a variety of advanced microscopy and spectroscopy techniques. In particular, the interfaces in the nanocomposites are often tailored (in engineered composites) and evolved (in biological nanocomposites) to unique molecular characteristics that provide optimized and superior properties to the nanocomposites. In this presentation, we will describe a multiscale mechanics perspective on role of molecular interactions as well as the nano and microstructures on the mechanics of nanocomposites. Specific examples including biological and synthetic nanocomposites will be presented. We have demonstrated a quantitative correlation of energies of molecular interactions albeit nonbonded in the nanocomposites to the …

Graphene/ Polymer Composites For Biomedical Applications: Tissue Scaffolds, Prosthetic Joints And Gene Delivery, Kaushik Chatterjee

Composites at Lake Louise (CALL 2015)

No abstract provided.

Self-Organized Soft-Hard Interfaces: From Surfaces To Biologically Integrated Hybrid Materials, Candan Tamerler

Composites at Lake Louise (CALL 2015)

The biological material systems promise the possibility of developing innovative materials that simultaneously self-assembled, self-organized and self-regulated; characteristics that are difficult to achieve in purely synthetic systems. Proteins play an essential role in fabrication of biological materials due to their diverse functions ranging from structural to biochemical. The ability to mimic any of these functions can be a game changer in designing new biomaterials. There are several challenges in these strategies including replicating the hierarchical organization of biological materials, organization that provides multi-scale structure/property interdependence. The interfacial interactions become critical in tuning the individual components towards the functional needs. There …

Nanoclay Based Composite Scaffolds For Development Of Novel Humanoid Environment, Kalpana Katti, Shahajahan Molla, Dinesh Katti

Composites at Lake Louise (CALL 2015)

Cancer cells are adept at invading, migrating to and colonizing on an organ away from its origin resulting in metastatic cancer. The process through which cancer cells colonize on a distant organ is known as metastasis. It is estimated that about 90% of the deaths associated with cancer are attributed to metastasis, yet the fundamental mechanisms of cancer metastasis are unknown. Several cancers are known to metastasize to bone. Of these, the most prolific are prostate, breast and colon cancers. Molecular, microstructural and physiological interactions between the metastatic cancer cells and bone microenvironment have been shown to be suggestive of …

Amorphous Metal Sandwich Composites With Unprecedented Strength, Jay Hanan

Composites at Lake Louise (CALL 2015)

Engineered cellular materials widely used in structural applications have similarity to those in nature. Wood, cork, and a human cancellous bone are examples of well-known natural cellular materials that resemble foams and honeycombs used for structural engineering applications. In structural applications, one role of a honeycomb core is to maintain separation between face sheets, often for specific point loads or a range of stress states from bending to compression or even expansion. This is best done with a minimal increase in weight. Therefore, lower densities are desired to maximize the advantage of a sandwich composite.

Achievable strengths in honeycombs are …

The Break Evolution Process In Composite Microcomposites, Gale Holmes

Composites at Lake Louise (CALL 2015)

The mechanical integrity of a structural composite is strongly affected by the strength and toughness of the fiber–matrix interface/interphase (Norwood, 1994), with interfacial shear strength (IFSS) considered the best quantifying metric. Because the IFSS outputs are used in unidirectional (UD) composite failure models (CFMs) to predict strength and failure behavior, where the interaction between fibers can be important, the validity of extrapolating from test results based upon the repeated failure of a single isolated fiber has often been questioned. In this presentation, the spatial distributions of fiber breaks in a single fiber fragmentation test (SFFT) specimen, such as used in …

Low Cost Synthesis Of Silicon-Based Ceramic Powders From Na, K And Cs Geopolymer, Cengiz Bagci, Gregory Kutyla, Walftraud Kriven

Composites at Lake Louise (CALL 2015)

Geopolymer carbon precursors (1:1:4.5:12+18C) for carbothermal reduction and nitridation were prepared by the following route. NaGP, KGP and CsGP resins were prepared by mixing metakaolin (Al₂O₃.2SiO₂) in NaOH, KOH, or CsOH alkaline solutions, respectively. The viscous and homogenous slurries was poured into a Teflon mold to obtain bar samples at ambient temperature and cured in a constant 50 °C temperature/humidity oven for 24 h. GP bars were powdered by following additional drying in an open air furnace at 300 °C for 1 h. To obtain GP18C precursors, the powdered pure GPs were ball milled …

Design And Fabrication Of Microstructured Composites Using Mechanical And Magnetic Stimuli, Rafael Libaroni, Randall Erb, Andre Studart

Composites at Lake Louise (CALL 2015)

Combining soft and hard building blocks is a widely used approach to fabricate composite materials exhibiting mechanical properties that are not achievable by their single components alone. Remarkably, the design strategies applied in engineering and biological processes lead to striking differences in the nano/microstructure and mechanical performance of such composite materials. While nature is able to grow composites with deliberate control over the orientation and spatial distribution of anisotropic reinforcing particles, the use of intricate and tailored architectures to optimize the mechanical and functional properties remains largely unexplored in synthetic materials. Although magnetic manipulation has been successfully applied as a …

Designer Electrocatalysts From Transition Metal Oxide Heterostructure, Jin Suntvich

Composites at Lake Louise (CALL 2015)

One of the largest cost and efficiency limitations of electrochemical energy storage and conversion devices such as fuel cells, electrolyzers and metal-air batteries lies in the sluggish kinetics of the oxygen electrochemical reactions. To increase the reaction kinetics and reduce the inefficiency, it is essential to find electrocatalysts that can facilitate and catalyze these electrochemical processes. Developing a “design” principle” that links material structure and chemistry to the catalytic activity can accelerate the search for highly active electrocatalyst that is cost effective and abundant in nature. In this contribution, we present our effort in establishing this structure-activity connection using transition …

Composites On Fire At Reduced Scale: Evaluation, Characterization And Modeling, Serge Bourbigot, Fabienne Samyn, Sophie Duquesne

Composites at Lake Louise (CALL 2015)

Composite materials are increasingly being used in the design of aircraft, train, ship and buildings. They are very often structural parts and they must meet the difficult challenge of having adequate structural fire protection. In fire scenarios of particular relevance according to the targeted applications, suitable strategies to control fire hazards are needed for composite structures. There are three main methods available to design composite structures with improved fire resistance behavior: (i) use “normal” structural materials and add surface protection, (ii) use fire retarded versions of “normal” structural materials, and (iii) use structural materials with inherently good fire retardant properties. …

Functional Nanogels Applied To Materials Development, Jeffrey Stansbury

Composites at Lake Louise (CALL 2015)

Nanogels are commonly used in the controlled delivery of therapeutic agents, DNA/RNA and proteins as well as for imaging and sensing in other biomedical applications. Nanogels are rarely utilized to modify or create macroscopic polymeric structure, which is the focus of this report. Our unique version of reactive polymeric nanogel materials involves globular particles that have well-controlled swollen dimensions of approximately 10 nm. These particles are composed of many short yet highly interconnected primary chains that cumulatively provide particles with molecular weights of 10⁴-10⁶ Da.