Polymer and Surface Science in the Youngblood Group › MSE › research › areas › ... · In...
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In 2003, Professor Youngblood joined the School of Materials Engineering at Purdue University. Promoted to Associate Professor in 2009 and Professor in 2015, he uses his polymer expertise to investigate nanotechnology, surface science, advanced processing and biomaterials. Of late, he has been specifically interested in ceramic processing using methods similar to those for polymeric materials, composites and fabrication, sustainability of materials, cellulose nanocomposites, cementitious materials, Additive Layer Manufacturing (3D printing), and durable anti-ice coatings. . v Polymer and Surface Science in the Youngblood Group Advanced Ceramic Processing . RESEARCH HIGHLIGHT Sustainable Nanotechnology Functional Materials S USTAINABLE FLAME R ETARDANTS Halogenated flame retardants (HFRs) are used in a variety of polymer systems. However, there is currently concern about their negative effects on health and the environment as bioaccumulation of HFRs in humans can lead to a variety of health issues. The goal of this project was to develop and study biologically-sourced chemicals as alternative FRs based on biomimetic design. Cured-in-place pipe (CIPP) is the resin saturated fabric liner that is installed into a deteriorated pipeline and then cured using steam, hot water or UV Light. Our goal is to analyze possible environmental effect during, and after installation of cured-in-place pipe (CIPP). A DVANCED POLYMER COMPOSITES Before CIPP Installation After CIPP Installation i.) Fiber Spinning Commercially available fiber spinning methods are being explored to produce high strength, high stiffness nanocellulose reinforced commodity polymer fibers where nanoparticle alignment and nanoparticle concentration are crucial to performance. We shown that CNC and CNF addition can increase modulus and strength of the fibers and can also add as a crystallinity nucleant. ii.) Hygroscopic Swelling of CNC Films Hygroscopic swelling is commonly characterized by the coefficient of hygroscopic swelling (CHS), which correlates the degree of expansion of a material to the mass intake of water as a function of humidity. CHS of self- organized and shear-oriented CNC films was determined by capturing hygroscopic strains produced by water vapor intake in equilibrium. Here, we use contrast enhanced microscopy digital image correlation (CEMDIC) to determine CHS as a function of CNC alignment. 500 μm Fast extrusion Polyvinyl alcohol/CNC Fibers i.) Laminates Laminates are made up of stacked layers of bio-friendly cellulose nanofibrils (oxidized CNF or mechanically fibrillated CNF) as the primary component with the addition of a thermoplastic polymer binder layer to achieve high strength, transparency and toughness. ii.) Nanocomposites CNC and CNF are potential additives and fillers for various polymer systems where it can act as a structural reinforcement, promote nucleation, and enhance thermal, mechanical and transport barrier properties. 3D Printing Cement with Controlled Architecture Additive manufacturing offers unique opportunities to design and test architectured cement-based materials. We have shown that “Bouligand” architectures with a pitch angle of 45° demonstrate a higher specific strength than cast specimens over a wide range of porosity. As well, we have shown that some architectures can provide flexibility, much higher toughness, and crack deflection in brittle cementitious materials. Professor Youngblood’s ceramic research focuses on structure-property- processing relationships of ceramic materials. In particular, we are investigating novel processing approaches for forming (ballistic and high temperature) ceramics and cements into complex shapes using powder- polymer suspensions as well as preparing transparent ceramic via alignment of -alumina platelets for armor applications. A QUEOUS BASED CERAMIC-POLYMER PROCESSING i.) Additive Manufacturing Current bulk ceramic forming processes are limited to simple structures or require secondary machining to add intricate features. Additive Manufacturing (AM) can be used with aqueous ceramic-polymer suspensions with tailored rheological properties to produce complex geometries. Presently, we are developing ceramic suspensions from different ceramic systems (B 4 C, Al 2 O 3 , Si 3 N 4 , ZrB 2 ) for use in AM. By tailoring flow properties of aqueous ceramic-polymer suspensions, injection molding can be accomplished at room temperature to produce samples with complex geometries. Combined with pressureless sintering, this results in parts with high relative densities and mechanical properties comparable to samples prepared by traditional forming methods. S TRUCTURED MATERIALS Transparent Ceramics Current methods for producing transparent ceramics involve extremely high sintering temperatures and/or complex and very large magnetic fields to align ceramic particles. By compression-molding a mixture of platelet-grain alpha- alumina in a thermoplastic polymer, a high degree of crystallographic alignment can be achieved. Subsequent binder burnout and densification will yield a dense, transparent, polycrystalline ceramic. 10 m ii.) Room-Temperature Injection Molding Injection molding of alumina slurry. 3D printing of a boron carbide slurry 3D printed sintered boron carbide part Schematic representation of moisture sorption of CNC films Shadow visible behind hot-pressed alumina Top: Architectured cement – a. honeycomb, b. twisting layers, c. hollow box with internal structure, d. double-modulus cement “spring”, e. Bouligand structure with 8 degree twist. Bottom: MOR vs density curve showing 3D printed architectures show anomalous strength behavior. Flame retardancy of natural products compare favorably to commercial FRs Structure of Tannic Acid Structure of Lignin (from Wikipedia) Water culvert before and after CIPP repair Mutliphasic mixture of VOCs, water, and partially cured polymer are released to the environment during steam curing of CIPP. CNC AND CNF PROCESSING N EW COMPOSITES F UNDAMENTAL P ROPERTY M EASUREMENT Platelet-grained alumina Optical birefringence method for anisotropy determination ???? Sustainable nanotechnology in the Youngblood group is primarily focused on cellulose nanomaterials (CN), which are sustainable, non-toxic, high strength, high stiffness, and derived from biomass. These materials are comprised of Cellulose Nanocrystals (CNCs) – rod-like liquid crystalline particles of 100nm length and Cellulose Nanofibrils (CNFs) – flexible fibrils of microns in length. Research into CNC and CNF spans new materials, new processing methods and fundamental property determination. Polylactic acid/CNC Fibers CNC R2R coating on PET film CNF laminates are highly transparent 20 bilayer CNF laminate structure CNC Epoxy nanocomposites show good dispersion CHS of CNC films with different CNC alignments CEMDIC image with CHS at an angular increment of 45 o i.) Optical Birefringence for Anisotropy Measurement Birefringence has been investigated for the determination of crystal orientation of a CNC film. The prime focus of our study is to establish a simple and low cost experimental technique using a standard UV–Vis spectrometer to determine the order parameter (S) for both isotropic and anisotropic configurations. The transmitted light intensity of CNC films between cross polarizers for the bright and dark fields were measured to determine the linear dichroitic ratio, which were used to calculate the order parameters of different crystalline arrangements. Transmittance peak intensity for a anisotropic film ii.) Roll to Roll (R2R) Continuous Fabrication A large-scale continuous manufacturing process for cellulose nanocrystal (CNC) and CNC composite coatings on a flexible substrate was developed in this work. In microgravure R2R, the coating thickness (from 2μm to 6μm) and CNC alignment can be controlled via process parameters and ink viscosity. Such processing is useful for producing barrier films to prevent oxygen, CO 2 and water transmission for food packaging and anti-bleed layers for printing. CNCs increase Degree of Hydration (DOH) in cement We have used these results to conduct field tests Increased DOH increases strength in cement CNCs reduce cement paste yield stress, yet improve degree-of-hydration (DOH) all at very low dosages. Lowered yield improves workability, while increased DOH increases strength. We are investigating the origin of these observations and how to improve CNC performance. We are now trying to apply CNC additives at the macro level during field tests. A DDITIVES FOR CEMENTITIOUS MATERIALS Sustainable energy sources need storage solution to reduce intermittency and provide stable power. However, current electrochemical storage are either too expensive or have to low capacity for such use. Here we investigate earth abundant materials such as biomass, sulfur and common metals such as sodium integrated with processing to lower cost. S USTAINABLE MATERIALS FOR ENERGY STORAGE a. Waste biomass such as pistachio shell can be carbonized and used for batteries. b. Performance depends on carbonization temperature. Functional Materials research in the Youngblood group seeks to create and investigate materials, additives and components that are “active” in some way – chemically, electrochemically, thermally, etc. The application fields can span the gamut of cement, batteries , polymer additives, anti-ice coatings and others.
Transcript of Polymer and Surface Science in the Youngblood Group › MSE › research › areas › ... · In...
In 2003, Professor Youngblood joined the School of Materials Engineering at Purdue University. Promoted to Associate Professor in 2009 and Professorin 2015, he uses his polymer expertise to investigate nanotechnology, surface science, advanced processing and biomaterials. Of late, he has beenspecifically interested in ceramic processing using methods similar to those for polymeric materials, composites and fabrication, sustainability ofmaterials, cellulose nanocomposites, cementitious materials, Additive Layer Manufacturing (3D printing), and durable anti-ice coatings.
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Polymer and Surface Science in the Youngblood Group
Advanced Ceramic Processing
.
RESEARCH HIGHLIGHT
Sustainable Nanotechnology Functional Materials
SUSTAINABLE FLAMERETARDANTSHalogenated flame retardants (HFRs) areused in a variety of polymer systems.However, there is currently concern abouttheir negative effects on health and theenvironment as bioaccumulation of HFRs inhumans can lead to a variety of health issues.The goal of this project was to develop andstudy biologically-sourced chemicals asalternative FRs based on biomimetic design.
Cured-in-place pipe (CIPP) is the resin saturated fabric liner that is installedinto a deteriorated pipeline and then cured using steam, hot water or UVLight. Our goal is to analyze possible environmental effect during, and afterinstallation of cured-in-place pipe (CIPP).
ADVANCED POLYMER COMPOSITES
Before CIPP Installation After CIPP Installation
i.) Fiber SpinningCommercially available fiber spinning methodsare being explored to produce high strength, highstiffness nanocellulose reinforced commoditypolymer fibers where nanoparticle alignment andnanoparticle concentration are crucial toperformance. We shown that CNC and CNFaddition can increase modulus and strength ofthe fibers and can also add as a crystallinitynucleant.
ii.) Hygroscopic Swelling of CNC FilmsHygroscopic swelling is commonly characterized by the coefficient ofhygroscopic swelling (CHS), which correlates the degree of expansion of amaterial to the mass intake of water as a function of humidity. CHS of self-organized and shear-oriented CNC films was determined by capturinghygroscopic strains produced by water vapor intake in equilibrium. Here, weuse contrast enhanced microscopy digital image correlation (CEMDIC) todetermine CHS as a function of CNC alignment.
500 µm
Fast extrusion
Polyvinyl alcohol/CNC Fibers
i.) LaminatesLaminates are made up of stackedlayers of bio-friendly cellulosenanofibrils (oxidized CNF ormechanically fibrillated CNF) asthe primary component with theaddition of a thermoplasticpolymer binder layer to achievehigh strength, transparency andtoughness.
ii.) NanocompositesCNC and CNF are potentialadditives and fillers for variouspolymer systems where it can actas a structural reinforcement,promote nucleation, and enhancethermal, mechanical and transportbarrier properties.
3D Printing Cement with Controlled ArchitectureAdditive manufacturing offers unique opportunities to design and testarchitectured cement-based materials. We have shown that “Bouligand”architectures with a pitch angle of 45° demonstrate a higher specific strengththan cast specimens over a wide range of porosity. As well, we have shownthat some architectures can provide flexibility, much higher toughness, andcrack deflection in brittle cementitious materials.
Professor Youngblood’s ceramic research focuses on structure-property-processing relationships of ceramic materials. In particular, we areinvestigating novel processing approaches for forming (ballistic and hightemperature) ceramics and cements into complex shapes using powder-polymer suspensions as well as preparing transparent ceramic via alignment of𝛼𝛼 -alumina platelets for armor applications.
AQUEOUS BASED CERAMIC-POLYMER PROCESSINGi.) Additive ManufacturingCurrent bulk ceramic forming processes are limited to simple structures orrequire secondary machining to add intricate features. AdditiveManufacturing (AM) can be used with aqueous ceramic-polymer suspensionswith tailored rheological properties to produce complex geometries. Presently,we are developing ceramic suspensions from different ceramic systems (B4C,Al2O3, Si3N4, ZrB2) for use in AM.
By tailoring flow properties of aqueousceramic-polymer suspensions, injectionmolding can be accomplished at roomtemperature to produce samples withcomplex geometries. Combined withpressureless sintering, this results inparts with high relative densities andmechanical properties comparable tosamples prepared by traditional formingmethods.
STRUCTURED MATERIALSTransparent CeramicsCurrent methods for producing transparent ceramics involve extremely highsintering temperatures and/or complex and very large magnetic fields to alignceramic particles. By compression-molding a mixture of platelet-grain alpha-alumina in a thermoplastic polymer, a high degree of crystallographicalignment can be achieved. Subsequent binder burnout and densification willyield a dense, transparent, polycrystalline ceramic.
10 𝜇𝜇m
ii.) Room-Temperature Injection Molding
Injection molding of alumina slurry.
3D printing of a boron carbide slurry 3D printed sintered boron carbide part
Schematic representation of moisture sorption of CNC films
Shadow visible behind hot-pressed alumina
Top: Architectured cement – a. honeycomb, b. twisting layers, c. hollow box with internalstructure, d. double-modulus cement “spring”, e. Bouligand structure with 8 degree twist.Bottom: MOR vs density curve showing 3D printed architectures show anomalous strengthbehavior.
Flame retardancy of natural products compare favorably to commercial FRs
Structure of Tannic Acid
Structure of Lignin (from Wikipedia)
Water culvert before and after CIPP repair
Mutliphasic mixture of VOCs, water, and partially cured polymer are released to the environment during steam curing of CIPP.
CNC AND CNF PROCESSING
NEW COMPOSITES
FUNDAMENTAL PROPERTY MEASUREMENT
Platelet-grained alumina
Optical birefringence method for anisotropy determination
????
Sustainable nanotechnology in the Youngblood group is primarily focused oncellulose nanomaterials (CN), which are sustainable, non-toxic, high strength,high stiffness, and derived from biomass. These materials are comprised ofCellulose Nanocrystals (CNCs) – rod-like liquid crystalline particles of 100nmlength and Cellulose Nanofibrils (CNFs) – flexible fibrils of microns in length.Research into CNC and CNF spans new materials, new processing methods andfundamental property determination.
Polylactic acid/CNC Fibers
CNC R2R coating on PET film
CNF laminates are highly transparent
20 bilayer CNF laminate structure
CNC Epoxy nanocomposites show good dispersion
CHS of CNC films with different CNC alignments
CEMDIC image with CHS at an angular increment of 45o
i.) Optical Birefringence for Anisotropy MeasurementBirefringence has been investigated for the determination of crystal orientationof a CNC film. The prime focus of our study is to establish a simple and lowcost experimental technique using a standard UV–Vis spectrometer todetermine the order parameter (S) for both isotropic and anisotropicconfigurations. The transmitted light intensity of CNC films between crosspolarizers for the bright and dark fields were measured to determine the lineardichroitic ratio, which were used to calculate the order parameters of differentcrystalline arrangements.
Transmittance peak intensity for a anisotropic film
ii.) Roll to Roll (R2R) Continuous FabricationA large-scale continuous manufacturing processfor cellulose nanocrystal (CNC) and CNCcomposite coatings on a flexible substrate wasdeveloped in this work. In microgravure R2R, thecoating thickness (from 2µm to 6µm) and CNCalignment can be controlled via processparameters and ink viscosity. Such processing isuseful for producing barrier films to preventoxygen, CO2 and water transmission for foodpackaging and anti-bleed layers for printing.
CNCs increase Degree of Hydration (DOH) in cement
We have used these results to conduct field tests
Increased DOH increases strength in cement
CNCs reduce cement paste yield stress, yet improvedegree-of-hydration (DOH) all at very low dosages.Lowered yield improves workability, while increasedDOH increases strength. We are investigating theorigin of these observations and how to improve CNCperformance. We are now trying to apply CNCadditives at the macro level during field tests.
ADDITIVES FOR CEMENTITIOUS MATERIALS
Sustainable energy sourcesneed storage solution toreduce intermittency andprovide stable power.However, currentelectrochemical storage areeither too expensive or haveto low capacity for suchuse. Here we investigateearth abundant materialssuch as biomass, sulfur andcommon metals such assodium integrated withprocessing to lower cost.
SUSTAINABLE MATERIALS FOR ENERGY STORAGE
a. Waste biomass such as pistachio shell can becarbonized and used for batteries. b. Performancedepends on carbonization temperature.
Functional Materials research in the Youngblood group seeks to create andinvestigate materials, additives and components that are “active” in some way –chemically, electrochemically, thermally, etc. The application fields can spanthe gamut of cement, batteries , polymer additives, anti-ice coatings and others.
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