Day 2 :
Keynote Forum
Rina Singh
Biotechnology Innovation Organization(BIO), USA
Keynote: Political landscape for bioplastics and biobased materials
Biography:
Rina Singh is director of policy in the industrial biotechnology and environmental section of the Biotechnology Industry Organization (BIO). She previously served as the business development manager at Ashland Inc. She was appointed by the president and CEO as a member of an innovative 10-member team assembled to develop a new strategic direction for Ashland, identifying investment opportunities for $1.5 billion resulting from the divestiture of petroleum refining operations. She held general management positions in the technology and business development areas of Ashland, including bioproducts business development manager and platform technology manager. She started her career at The Dow Chemical Co as a senior research chemist in the Engineering Thermoplastics Group. The holder of 24 patents and publications, Singh received a BS, a doctorate in natural products (synthetic organic chemistry) and a post-doctoral degree in polymer science from McGill University.
Abstract:
There continues to be an increased interest in synthesizing renewable chemicals from renewable resources, even with the downturn in the economy, which has slowed down the time it takes to reach commercial reality, but there still continues to be partnerships and business deals in the making. As a result of the early commercialization of renewable chemicals such as 1,2-propylene glycol, 1,3-propanediol, bioethanol, polylactic acid (PLA), polyhydroxyalkanoates (PHA), and more recently, polyethylene terephthalic acid (PET), this has encouraged interest nationally and internationally to further build on these early successes. Investments through partnerships are occurring globally involving a multitude of startup companies and amongst mature chemical companies engaged in building their product portfolios. There is interest in complementing existing product pipelines from incumbent technologies with renewably derived products from renewable sources, providing options for consumers to select sustainable products. Now there are both federal and state policies encouraging the growth in this sector, which once, were only in discussion stages. The presentation will focus on the policies impacting the growth of the sector and will provide the commercial status of building blocks for bioplastics and biobased materials.
- Polymer Material Science and Engineering | Biomaterials and Biopolymers | Polymer Science – The Next Generation
Location: Copa A
Chair
Ebru Gunister
Khalifa University of Science and Technology, UAE
Session Introduction
Chao Yang
Fritz Industries, USA
Title: A novel relative permeability modifier polymer
Biography:
Chao Yang has obtained his PhD degree in chemistry from Virginia Tech. He has been working in stimulation and production chemicals since 2013.
Abstract:
A new relative permeability modifier (RPM) has been developed for sandstone formations that are capable of reducing the permeability to water without impairing the permeability to oil. The new polymer has the capacity to anchor to the formation, allowing it to endure production fluid flow. Laboratory data were obtained in core flow test using high permeability sandstone cores (1.5 to 2 Darcies air permeability Berea Sandstone) at 200o F. The core flow sequence followed was to measure the relative permeabilities of oil at irreducible water (2% KCl) saturation and to water (2% KCl) at irreducible oil saturation before the injection of the RPM polymer. Then, the RPM polymer solution was injected into the core in the opposite direction (injection direction). The system was shut-in for one hour to facilitate polymer anchoring and re-organization. The relative water saturation was then determined by injecting 2% KCl in the production direction, followed by the oil relative permeability. One last water permeability was measured with 2% KCl after the oil permeability to determine the ability of the polymer to anchor to the core. Results indicate that the polymer can remarkably reduce the permeability to water without significantly impairing the permeability to oil. The regain relative water permeability was less than 20% after the injection of RPM polymer; the subsequent regain relative oil permeability was more than 75% and the regain relative water permeability was less than 30% after the oil injection. Results also indicated the RPM polymer had similar performance regardless of the injection direction used. Moreover pre-flushing the core with mutual solvent and surfactants before the polymer treatment did not have a significant effect on the performance of polymer. The capacity to selectively modify the water permeability makes it feasible to use this RPM polymer as near wellbore or far field treatment to reduce the excessive water production. Moreover, the polymer can be applied without the use of a mutual solvent and surfactants.
Biography:
Andrej Holobar has completed his PhD at the Karl Franzens University Graz, Austria, on chemical optical sensors for bioprocesses and finished postdoctoral studies at the Biotechnical University in Ljubljana. He is the CEO for research and development in company ECHO Instruments he has founded in 1992. He leads several EU projects in the field sensors and measuring technologies in combination with robotic systems. He is also a chemical adviser in REACH and SEVESO Europe directive.
Abstract:
A certificate gives the producer of the product the right to mark it with an approved logo that is accompanied with the serial number of the certificate. In Europe, independent certificates for biodegradable plastics are issued by EU standards. Compostable plastics are a subset of biodegradable plastics that biodegrade within the conditions and timeframe of the composting process. Compostable is always biodegradable while the biodegradable material is not always compostable. European Standard EN 13432 is part of a whole series of standards prepared under a mandate from the EU to support the implementation of the Directive on Packaging and Packaging Waste (94/62/EC). One of the test methods for assessing biodegradability is ISO 14855 for determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions. With the use of respirometer, it is possible to have an accurate, fast and reliable test for biodegradable materials under aerobic composting conditions. A new type of automated analysis with the implementation of new sensor technology with intelligent software control helps users to have fast results with maximal data evaluation. The new respirometry systems can be used in government accreditation institutions, production of raw material and products as well as research faculties and institutes.
Marcio Dias Lima
Nano-Science and Technology Center, USA
Title: Twisted polymeric fiber based actuators
Biography:
Marcio Dias Lima is currently Chief Application Scientist at the Nano-Science and Technology Center, part of Lintec of America. Previously he worked as Research Scientist at Prof. Ray Baughman’s group at the Alan G MacDiarmid NanoTech Institute. He obtained his Dipl.-Ing. Degree in Materials Engineering from the Federal University of Rio Grande does Sul (Brazil) in 2001. At the beginning of 2005 to 2007 he became a member of Dr Roth research group at the Max Plank Institute of Solid State Research in Germany as visiting PhD candidate. Research interests include artificial muscles, synthesis of carbon nanotubes, development of hybrid carbon nanotubes yarns and sheets for energy conversion and storage, high strength composites and nanostructured transparent and conductive films. He has 50 refereed publications (4385 citations, H-index 31) and 6 issued patents.
Abstract:
It has been demonstrated that highly twisted polymeric fibers are also capable to generate impressive tensile actuation, providing large strokes and vastly exceeding the work and power capabilities of natural skeletal muscle. Contraction of over 50% and lifting capacity up to 270 pounds weight have achieved using a single coiled fiber. These actuators are also can operate as torsional motors: a thin fiber can rotate heavy rotors at up to 100,000 rpm for 1,000,000 cycles. Actuation can be driven by electrical signals or by relatively small variation in environmental temperature, which can be converted into mechanical work. That allows the use of these new actuators for automatic temperature and airflow control and natural light absorption or reflection in small and large structures such as residences and factory installations. Fig. 1 shows an example of environmental temperature control using only twisted polymeric fibers which are capable to open and close the roof a simulated greenhouse in order to regulate its internal temperature. Another field of applications is on soft-robotics: since these actuators are very flexible, capable to produce large tensile strength and easily assembled into arrays they are suitable for construction of soft manipulators
Biography:
Namrata Tripathi is currently an Instructional Assistant Professor of Physics at Illinois State University, USA. She received her PhD from Indian Institute of Technology Kharagpur, India. Her research has been focusing on solid polymer electrolyte for energy storage devices such as batteries. Her research has provided important insight in structure-property relation in polymer-nanocomposite electrolytes and contributes to the value of future designs of advanced batteries. She serves as an editorial board member of International Journal of Electrical Components and Energy Conversion.
Abstract:
Increasing global warming triggered the urgent need for the reduction of greenhouse gas emission and pollution. It can be effectively achieved by replacing conventional combustion-engine vehicles with sustainable electric or hybrid vehicles. But the success of electric vehicle is facing challenges associated with lithium-ion batteries such as low energy efficiency, high cost, and risk of fire. To make electric, hybrid vehicles more attractive to consumers, the batteries that power those cars need to be affordable, high performing, long lasting, safe, and operate at maximum efficiency in a wide range of driving conditions and climates. In this regard, solid polymer electrolytes could be a real game-changer creating a perfect battery for an electric vehicle, solving most of the issues like battery lifetime, safety, and cost. However poor ionic conductivity of solid polymer electrolyte limits their practical applications. Technological applications of this class of materials require high ionic conductivity. To enhance the ionic conductivity to the required level and beyond, several new approaches have been adopted. To achieve the required conductivity and to suggest ways for improvement, the conduction mechanism and transport properties of such materials need to be better understood. The conductivity of PNC is mostly a function of the number of charge carriers and their mobility. Hence, to understand the conduction mechanism, it is most important to determine number density and mobility of charge carriers quantitatively. A number of techniques have been used, including nuclear magnetic resonance, transient ionic direct current measurement, dielectric analysis, and electrochemical impedance spectroscopy (EIS) method. I will discuss dielectric analysis and EIS method in detail to understand ion conduction mechanism in polymer nanocomposite.
Balázs Pásztói
Eötvös Loránd University, Hungary
Title: Synthesis, characterization and thermoresponsive behaviour of hydrophobically modified poly(2-ethyl-2-oxazoline)s
Biography:
Balázs Pásztói started his PhD in 2015 at the Eötvös Loránd University in Budapest, Hungary. He currently works as a research assistant at the Polymer Chemistry Research Group of RCNS HAS. His research topic involves mainly the synthesis of functional polyisobutylenes and the investigation of the thermoresponsive behavior of polyoxazolines.
Abstract:
Poly(2-alkyl-2-oxazoline)s belong to a synthetic class of unique polyamides with pendant amide groups. These polymers can be prepared by quasi-living cationic ring-opening polymerization (CROP) of 2-alkyl-2-oxazoline monomers. This highlighted group of macromolecules is of great interest for biomedical applications due to their biocompatibility and biodegradability. Poly(2-ethyl-2-oxazoline)s (PEtOx) possesses thermoresponsive behavior and critical solution temperature (CST) in water. This phenomenon can be tuned by the structure of the polymer by either with the variation of the 2-substituent or applying end-group modifications. For accurate control of the hydrophilic-hydrophobic balance of the macromolecule, quasi-living CROP of 2-alkyl-2-oxazolines gives an excellent opportunity with the broad selection possibility of initiators and terminating (quenching) agents. In our work, thermoresponsive poly(2-ethyl-2-oxazoline)s were prepared by quasi-living CROP with different average molecular weights. Several initiators and terminating agents were used in order to result in monofunctional and bifunctional, hydrophobically modified, amphiphilic type macromolecules. The hydrophilic-hydrophobic balance of these polyoxazolines can be controlled by the choice of the initiator, terminating agent and the molecular weight. The thermoresponsive behavior of the synthesized products was comprehensively studied by turbidimetry in a wide concentration range. A strong influence on the CST values was determined as a function of the chain length and presence of alkyl end-groups.
Mayra A Mendez-Encinas
Research Center for Food and Development (CIAD), Mexico
Title: Gels of ferulated arabinoxylans: Functional properties and potential application as drug delivery systems
Biography:
Mayra Mendez-Encinas has completed her MSc at Research Center for Food and Development, CIAD, Mexico which included an academic stay at ERRC, ARS, USDA (Wyndmoor, PA, USA). She is studying a PhD at CIAD. Her research interest is focused on extraction and characterization of polysaccharides from renewable resources, particularly ferulated arabinoxylans, arabinoxylan gels and their potential application as an antioxidant and anticancer agent. She has published three book chapters and has attended two International Conferences, the 2017 MRS Spring Meeting & Exhibit (Phoenix, AZ, USA) and the 19th Gums & Stabilizers for the Food Industry Conference, 2017 (Berlin, Germany).
Abstract:
Interest in biopolymers has increased due to their numerous advantages for application in biomedical and pharmaceutical fields. Among biopolymers, polysaccharides represent an excellent alternative for the design of drug delivery systems. Arabinoxylans (AX) are non-starch polysaccharides from cereal grains. AX consists in a linear β-(1-4)-D-xylopyranosyl backbone to which α-L-arabinofuranosyl residues are attached on O-2 and/or O-3 positions. Some ferulic acid (FA) molecules are esterified to arabinoses on O-5. AX form covalent gels in presence of free radical-generating agents through the oxidative coupling of FA molecules, leading to the formation of dimers and trimer of FA and resulting in the gel network. AX gels exhibit stability to pH and temperature changes and high water absorption. These gels have been studied as matrices for the controlled release of biomolecules and cells, demonstrating its potential application in pharmaceutical, biomedical and food industries. AX has prebiotic, antioxidant and antiproliferative properties. AX gels can be fermented by the colonic microbiota and recent in vivo studies have demonstrated that administration of AX gels to obese rats increase bifidobacteria population and limit Bacteroides, suggesting a prebiotic effect. In addition, AX gels exhibit antioxidant activity in vitro. The antiproliferative activity of AX appears to be related to its antioxidant and prebiotic properties. In this regard, the study of the antiproliferative activity of AX gels and its relationship with their prebiotic and antioxidant properties should be considered. Thus, AX gels can be promising drug delivery systems presenting antioxidant and antiproliferative properties.
Ana M. Morales-Burgos
Research Center for Food and Development (CIAD), Mexico
Title: Arabinoxylans properties and the microspheres production for colon-targeted insulin delivery
Biography:
Ana M Morales-Burgos has completed her Master degree in Biotechnology at the University of Guadalajara and she is actually finishing her PhD studies in Biopolymers at the Research Center for Food and Development in Mexico. She has published 1 paper and 2 chapters in reputed editorials and her research studies are focused on the extraction and characterization of natural polymers and the development of biomaterials.
Abstract:
Arabinoxylans (AX) are biopolymers present mainly in cereal grains, they are fermentable by colonic bacteria and able to form covalent gels through the oxidation of ferulic acid molecules. These gels are low affected by pH changes and suitable for colon-targeted insulin administration. The aim of this work was to study arabinoxylans properties and to produce and analyze AX-insulin microspheres. AX obtained from maize bran presented high ferulic acid content (22.4±0.9ïg/mg) and an arabinose to xylose ratio of 0.6. The antioxidant activity of AX was studied by ABTS and DPPH assays obtaining the IC50 values of 1050.9±24.6 and 681.1±41.2ïg/ml, respectively. The gelation property of 1% (w/v) AX solutions was analyzed by rheology using laccase. Gels with a storage modulus of 530 Pa and a mechanical spectrum characteristic of a solid-like material were obtained. A triaxial electrospray system was used to prepare AX-insulin microspheres with a mean diameter of 240ïm and a uniform insulin distribution as observed by confocal laser scanning microscopy. During the in vitro analysis under simulated gastrointestinal conditions, 20±0.5% of encapsulated insulin was released. Finally, the in vivo analysis performed in Wistar rats presenting type I diabetes induced by streptozotocin showed a hypoglycemic effect from 16 to 18h after AX-insulin microspheres oral administration. The results suggest AX microspheres as an attractive colon-targeted drug delivery system. Further studies are needed to investigate the insulin stability in the AX microspheres during storage.
- Biopolymer and Polymer Application | Polymer Chemistry | Biodegradable Polymers
Location: Copa A
Chair
Ari Rosling
Arctic Biomaterials LTD, Finland
Session Introduction
Ebru Gunister
Khalifa University of Science and Technology, UAE
Title: The effect of graphene oxide (GO) filler on the mechanical properties of polyethylene
Biography:
Ebru Gunister has completed her PhD from Istanbul Technical University. She is an Assistant Profesor in The Petroleum Institute as a part of Khalifa University of Science and Technology. She has over 15 years of research experience in the areas of materials science; clay modifications, rheological and electrokinetic behavior of clay and modified clay dispersions, polymer/clay composites, and biocomposites. She worked as Principal Investigator in Polymer/Clay Nanocomposite project and currently she has been working in Polymer/Graphene Composites projects as co-investigator. She has published more than 18 papers in reputed journals and book chapters.
Abstract:
Polyethylene (PE) is one of the commodity plastic used in various industry due to its good processibility, varies physical properties based on its linear or branched structure. In the past thirty years, there is a high interest to develop physical properties of polymers using low cost but effective additives. Graphite, graphene, graphene oxide (GO), carbon nanotubes, carbon fibers are some of the carbon-based fillers used to form polymer matrix composites. In this research, PE/GO composites with GO loading ranging from 0 wt.% to 2 wt.% are prepared by using a melt compounding method. The samples for characterizing and mechanical testing are shaped by injection molding machine. The mechanical properties of PE composites are investigated by tensile and fatigue test and hardness tests. The morphology and thermal characterization of PE/GO composites are determined by using X-ray diffractometer (XRD), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC). Based on the mechanical test results; the tensile strength, Young’s modulus, and Shore D hardness value were increased by 27.4%, 31.3%, and 9%, respectively, with a GO loading. The number of cycles to failure in fatigue test for 2 wt.% GO addition to PE sample is increased up to 100 times more than pure PE. The morphological analysis via XRD and TEM indicated that GO nanolayers were well exfoliated in the PE matrix. Based on DSC analysis results, GO addition to PE has negligible effect on thermal transitions of the PE matrix.
Ari Rosling
Arctic Biomaterials LTD, Finland
Title: New era of biodegradable polymers and biocomposites
Biography:
Ari Rosling completed his PhD at the age of 35 years from Abo Akademi University (organic chemistry) after which he was appointed assistant professor at Department of Polymer Technology, responsible for the development of biomaterial research. At present he acts as Senior Research Fellow at Arctic Biomaterials, being in charge of the R&D activities at the technical site. He has published more than 42 papers and patents in reputed journals and led numerous joint research projects with industrial partners.
Abstract:
In the recent years, bio-based and biodegradable products have raised great interest because sustainable development policies tend to expand with the growing concern for the environment and the use of non-renewable resources. Arctic Biomaterials LTD (ABM) is a company producing bio-based and/or biodegradable compound and composite solutions for demanding technical and medical applications. Our in-depth and specific biopolymer knowledge is offered to our customers to develop biomaterials to meet their needs. The bioerodible glass fiber reinforced materials produced with ABM’s own technology, enables fulfilling customer needs in high demanding technical and medical applications, offer a sustainable alternative to several oil-based technical plastics. The composite materials are produced on our long-fiber-reinforced thermoplastic (LFT) line. This proprietary bioerodible long glass fiber compounding technology increases the ABM composite materials heat resistance and mechanical properties to new levels and opens a variety of possible application areas in fields where durable technical plastics are being used. Along with the sustainable aspects, processability and physicomechanical properties ABM also produces the aforementioned materials with additional specific high-value functionalities, e.g. antistatic, flame resistance, antimicrobial and colored products.
Biography:
Rakkiyappan Chandran has completed his PhD at the age of 28 from Joint School of Nanoscience and Nanoengineering (JSNN) at the University of North Carolina, Greensboro. Prior to his PhD, he did his joint Master’s Degree project from Harvard Medical School at the Wellman Center for Photomedicine, Massachusetts General Hospital and further went on being a research assistant at MIT for a year. He then Joined Triad Polymers, as a Research and Development Scientist and is also a joint consortium member of JSNN. He has published more than 20 papers in reputed international scientific and peer-reviewed journals, with a book and 3 chapters on polymeric biomaterial and tissue engineering.
Abstract:
Composite surface topographies control and determine the properties of insect cuticles. In some cases, these nanostructured materials are a direct extension of chitin-based cuticles. The cellular mechanisms that generate these structures are unknown and involve complex cellular and biochemical “bottom-up” processes. A synthetic “top-down” fabrication nanosphere lithography techniques can generate surfaces of chitin or chitosan that mimic the surface of the native nanostructure of certain insect wings and eyes. Biopolymer chitin and chitosan are flexible, biocompatible and abundant in nature. The fabrication of nanostructured chitin and chitosan materials could enable the development of new properties in biopolymeric materials. Also, the ability to generate a self-masking thin film and leads to synthesis and formation of metallic nanoparticles enables a novel and powerful new tool for generating structured composite biomaterials. These crystalline metallic nanoparticles then served as seeds for the solid-state formation of nanowires within a drop-cast thin film by providing a flexible biopolymeric/metallic nanocomposite material. This information provides insight into the mechanisms that are essential for in vitro nanoscale manipulation of polymer in hydrogels and other synthetic biomaterials. The biomimetic nanostructured surfaces (NSS) formed through biopolymer scaffolds have potential applications for various defense and biomedical technologies.
Michael Lubwama
Makerere University Kampala, Uganda
Title: Mechanical and thermal properties of Bio-composite polymers reinforced with rice and coffee husks
Biography:
Michael Lubwama completed his PhD in Mechanical Engineering in 2013 from Dublin City University, Ireland. He is a lecturer at the Department of Mechanical Engineering, Makerere University. He is also the Deputy Center Leader of the Africa Center of Excellence in Materials, Product Development, and Nanotechnology.
Abstract:
In this study, rice and coffee husks were incorporated with Polypropylene to form bio-composite polymers. Injection moulding technique was employed in their production process. Filler material loading varied between 0-20% and 0-10% for rice husks and coffee husks respectively. Biochemical analysis was carried out to understand the effect of the cellulose, hemicellulose, and lignin in the filler material on the properties of developed bio-composite polymers. Thermal properties were determined using differential scanning calorimetry, chemical properties were determined using a burning test and mechanical properties were determined using a universal testing machine. Overall, the husks had high cellulose contents but low lignin and hemicellulose contents. For coffee husks and rice husks incorporated bio-composite polymers respectively, Young's modulus was between 1780MPa-1967MPa and 1786MPa-2248MPa, tensile strength varied between 28MPa-36MPa and 31MPa-36MPa, elongation at break ranging between 2%-11% and 5%-12%, notched impact strength varied between 1.2 kJ/m2-4 kJ/m2 and 2.2 kJ/m2–3.5 kJ/m2. Filler content had no effect on the transition temperatures. Increasing filler contents led to decreasing crystallization and melting enthalpies i.e. increase in filler content reduced the percentage of the melt-able matrix. Generally, higher filler content led to higher Young's modulus, lower tensile strength, and elongation at break, lower crystallization, and melting enthalpies. No significant correlation was observed between the filler content and the impact strength. High cellulose contents explain why the mechanical properties stayed at acceptable values. Low lignin and hemicellulose contents correspond to improved adhesion between the polymer and matrix materials owing to more exposure of the hydroxyl groups.
Alok Gupta
Malaviya National Institute of Technology, India
Title: Synthesis and characterization of emulsion polymerized polyaniline doped with DBSA
Biography:
Alok Gupta has completed his PhD in the year 1988 from Indian Institute of Technology-Kanpur on the topic Modelling of Hydrolytic Polymerization of Caprolactam and Transport Processes in Nylon-6 Reactors. He is currently designated as Professor in Malaviya National Institute of Technology, Jaipur, Rajasthan, India. He has published more than 30 papers in reputed journals and has been a reviewer of three journals namely African journal of pure and applied chemistry, Indian Chemical Engineer Journal, Indian Journal of Chemical Technology. He is also being the lifetime member of “ American Institute of Chemical Engineers” and “ Indian Institute of Chemical Engineers”.
Abstract:
In this abstract polyaniline (PANI) has been made through polymerization of aniline using emulsion polymerization technique. The polymerization is carried out in an emulsion comprising water and a non-polar or weakly polar organic solvent (Xylene) in the presence of the functionalized protonic acid dodecylbenzenesulfonic acid (DBSA). It is found that using the emulsion polymerization technique, conducting PANI-DBSA complexes can be produced that exhibit high molecular weight, good conductivity and high solubility in organic solvents in the electrically conducting state. Electrically conducting polyaniline PANI-DBSA prepared by an inverted emulsion polymerization in which DBSA played both roles of surfactant and dopant. Fourier transform infrared FTIR. spectroscopy for the PANI-DBSA showed the existence of hydrogen bonding between PANI and DBSA which indicates the existence of PANI. UVV is spectra was performed to check the doping level of DBSA. The electrical conductivity measurement, TGA test, and measurement of viscosity were also studied in the paper.
Shahab Kashani Rahimi
University of Southern Mississippi, USA
Title: Graphene/hydroxyl ethyl cellulose aerogels for deformation sensing
Biography:
Shahab Kashani Rahimi is currently a postdoctoral fellow in Prof. Joshua Otaigbe research group at the school of polymers and high-performance materials of the University of Southern Mississippi. He completed his PhD thesis under Prof. Otaigbe’s supervision on developing a new technology to fabricate cellulose reinforced engineering thermoplastic composites using in situ ring-opening polymerization of cyclic monomers. He is currently working on graphene and nanofibrillated cellulose aerogels for deformation sensing and tissue engineering applications.
Abstract:
Graphene, a one-atom-thick 2-dimensional carbon nanomaterial has received considerable attention from researchers in various disciplines due to its exceptional thermal, mechanical and electrical properties owing to its unique long-ranged π conjugated structure. Due to its unique structure and properties, it has found numerous applications ranging from polymer composites, electronics, and biomedical devices to energy storage and sensors. One of the interesting applications of graphene is in flexible superelastic deformation/strain sensors. For this purpose, flexible porous graphene-based superstructures are good candidates due to their elasticity, high surface area, electrical conductivity, and low density. However, due to severe aggregation of graphene platelets, these graphene aerogels (GAs) tend to be brittle with irrecoverable deformation and properties. In order to address this issue, a number of different polymers such as polyacrylic acid and sodium alginate have been used as a component in conjunction with graphene. However, a systematic study focused on the analysis of the aerogel component variables and its subsequent effects on final structure and properties is still needed in order to get a better understanding of the processing-structure-property relationships of such aerogels. This study reports on the preparation of a series of graphene aerogels in combination with hydroxyl ethyl cellulose (HEC) building block. The effects of the molecular weight of the HEC and crosslinking of the HEC phase with glutaraldehyde and aerogel composition on the structure and properties of the final aerogels are presented. It was found that the use of low molecular weight HEC (92kDa) at the appropriate concertation can develop honey-comb porous structure with superior mechanical properties, high porosity, rapid deformation response, as well as, significantly lower deformation hysteresis.
Jorma Antero Virtanen
Tesla NanoCoatings, Inc., USA
Title: Electromagnetic properties of carbon nanotube-cellulose, or hemicellulose nanocomposites
Biography:
Jorma Virtanen has masters in Organic Chemistry, and Mathematics at University of Helsinki, and Ph.D. in Physical Chemistry at University of Helsinki. He has been visiting scientist at Arizona State University, and University of California in Irvine. He has about 80 papers in peer reviewed journals. He is the inventor of CNT-epoxy that was named “The Best Nanoproduct in the World” in year 2006 in Tokyo. He and the group also got Frost&Sullivan Nanotechnoogy Award 2009.
Abstract:
Cellulose and hemicellulose form a nanocomposite with doublewall (DWNT) and multiwall (MWNT) carbon nanotubes. Water dispersions of these nanocomposites are uniform and stable. Films of DWNTs-hemicellulose are electrically highly conducting, corresponding to a bulk conductivity of 2000 Scm-1. Transparent (T%>90 %) films can have the surface resistance below 100 W/â˜. Corresponding MWNT films have about 10-fold resistance. Conductivity is almost constant between 30 and 400 K. Kelvin probe force microscopy, and terahertz conductivity were used to study inter-tube charge transport. These films have good EMI shielding properties. Transparent DWNT-hemicellulose films may have 30 dB EMI attenuation in 0.1 – 10 GHz range. MWNT-hemicellulose films may be used as anti-radar stealth coatings. Also the use of these materials in supercapacitors, and 3D printing will be discussed. Overall these materials that are completely recyclable can replace many rare metals in numerous applications often with equal or better performance.
Shahab Kashani Rahimi
University of Southern Mississippi, USA
Title: The Structure, property and biocompatibility of poly (butylene adipate-coterephthalate) / cellulose whiskers nanocomposites prepared by reactive extrusion
Biography:
Shahab Kashani Rahimi is currently a postdoctoral fellow in Prof. Joshua Otaigbe research group at the school of polymers and high-performance materials of the University of Southern Mississippi. He completed his PhD thesis under Prof. Otaigbe’s supervision on developing a new technology to fabricate cellulose reinforced engineering thermoplastic composites using in situ ring-opening polymerization of cyclic monomers. He is currently working on graphene and nanofibrillated cellulose aerogels for deformation sensing and tissue engineering applications.
Abstract:
Cellulose whiskers (also known as cellulose nanocrystals) are unique rod-like nanomaterials derived from cellulose fibers which are the most abundant natural polymer. They have been the subject of extensive research efforts in the past decade due to their exceptional properties such as very high stiffness with an elastic modulus of a single crystal in the range of 100-150GPa, lower density compared to carbon or silica-based nanomaterials, bio-renewability and unique rheological and optical properties. Being a bio-based material; they have received significant attention for their potential use in tissue engineering and biomedical applications in conjunction with biocompatible polymers. However one of the challenges in the application of cellulose whiskers in polymer composites and nanocomposite is the difficulty of effectively dispersing these materials in polymer matrices especially non-water soluble polymers. This study reports on the development of a fully biocompatible poly (butylene adipate-co-terephthalate)/CNC nanocomposite prepared via reactive extrusion and investigation of the structure-property relationship in these systems. PBAT was first modified with maleic anhydride groups using an in situ melt extrusion process in order to promote the interfacial reaction with the surface hydroxyl groups of the CNCs. The nanocomposites are then prepared with up to 9% CNC in the following melt extrusion step. Analysis of the mechanical and thermal properties of these nanocomposites showed significant improvement in tensile strength, modulus and glass transition of the matrix. The 3D nanostructure of the CNC within the PBAT was studied by shear rheological techniques and the framework of scaling theory of fractal elastic gels. In vitro biocompatibility using Thiazolyl blue tetrazolium bromide (MTT) assay and cell adhesion studies with L929 fibroblast cells revealed no cytotoxic effect of CNCs while providing evidence for enhanced cell adhesion with the presence of cellulose nanocrystals in PBAT matrix.