Materials Characterization by Thermal Analysis (DSC & TGA ...

1 Materials Characterization by Thermal Analysis (DSC & TGA), Rheology, and Dynamic Mechanical AnalysisCharles Potter Thermal Application ScientistSarah Cotts Rheology Application ScientistFred Wiebke Territory Manager TA InstrumentsFacts about TA Instruments Global market leader in Thermal Analysis , thermophysical properties, microcalorimetry and rheology. Headquartered in New Castle, DE along with 200,000 sq. ft. of manufacturing and support Additional manufacturing in Utah and Germany Direct Sales Offices in 28 countriesWhat Does TA Instruments Measure?

2 Thermal Analysis & RheologyDSC, DTCTGADMA RheometerTMADILT hermal Analysis , Rheology,Thermophysical Properties Techniques Differential Scanning Calorimetry (DSC) Modulated DSC Thermogravimetric Analysis (TGA) Vapor Sorption Analysis (SA) Dynamic Mechanical Analysis (DMA) Rheometer Isothermal Calorimetry (TAM) Thermomechanical Analysis (TMA) Flash Diffusivity Thermal Conductivity Dilatometry (DIL)Agenda Morning: Techniques and Applications Case Study Automotive Industry Differential Scanning Calorimetry Thermogravimetric Analysis Simultaneous Differential Thermal Analysis Complimentary Thermal Analysis Techniques Afternoon: Techniques and Applications: Dynamic Mechanical Analysis (Q800 and RSA) Rheology (DHR and ARES) Techniques and Applications Case Studies Rheology/DSC/TGA/SDT Rubber Rheology Case Studies Rubber Rheology and DSC Load Frame High Force, Fatigue TestingWrap up about 4.

3 00 pm- Case Study - Thermal Analysis in the Automotive IndustryComposition of an AutomobileBuilding a Lighter Automobile30% weight reduction50% weight reductionAluminum Tailor Welded Blanks40% weight reduction / 50% reduction in part countSuperplastic Forming35% weight reduction / reduction in part count40% weight reduction / 10 X reduction in part countHydroformingMetal Matrix CompositesPowertrain components - 40% weight reduction Reduces mass by 60%Magnesium AlloyLightweight GlazingThermoplastic CompositesPhoto: Courtesy of GKN AerospaceWhat is Thermal Analysis ?

4 Thermal Analysis is a series of techniques that provide physical property measurement as a function of temperature, time, and other Techniques Differential Scanning Calorimetry (DSC) - heat Modulated DSC (MDSC ) Thermogravimetric Analysis (TGA) weight Simultaneous DSC/TGA (SDT) Vapor sorption Analysis Thermomechanical Analysis (TMA) - dimension Dynamic Mechanical Analysis (DMA) - modulus Can also be considered a solids rheometer Analysis of Automotive Materials What is it? Thermoplastics Thermosets Amorphous Material Rubber and Elastomers What is it?

5 What is it? or What is it not? DSC and TGA, along with infrared spectroscopy, are an excellent starting point for Characterization of new or unknown Canada You will need a bunch of this to buy anything .. including a CAR-2-10123 Heat Flow T4P (W/g)-50050100150200250 Temperature ( C) Exo UpUniversal TA InstrumentsThermoplastic Polymers Agenda Thermoplastics What are thermoplastics? Melting Crystallization Crystalline Content Thermal Stability Oxidative StabilityThermoplasticsSemi-Crystalline (or Amorphous)Crystalline Phasemelting temperature Tm(endothermic peak)Amorphous Phaseglass transition temperature (Tg)(causing Cp)Tg < TmCrystallizable polymer can crystallize on cooling from the melt at Tc(Tg < Tc < Tm)DSC Melting of Polyethylene vs Indium100110120130140150160170-20-15-10- 505 Temperature ( C)Heat Flow (mW) CDifferent Types of PolyethylenePeak shape depends on.

6 Molecular weight distribution and branching Crystallinity Crystallite morphology as determined by Thermal history Differences affect end-use performance-20-15-10-50 Heat Flow (W/g)406080100120140160 Temperature ( C)Exo UpCrystallization Crystallization is an exothermic peak in a DSC scan Crystallization is molten amorphous material changing to crystalline material upon cooling Cold-Crystallization is solid amorphous material changing to crystalline material upon heating Crystallization is a kinetic, two-step process Nucleation Crystal growthCrystallization Crystallization is a kinetic process which is typically studied either while cooling or isothermal, but can also be studied during heating (Cold-Crystallization)

7 Differences in crystallization temperature or time (at a specific temperature) between samples can affect end-use properties as well as processing conditions Isothermal crystallization is the most sensitive way to id entify differences in crystallization rates Effect of Cooling RateCoolingRe-crystallization20 C/min10 C/min5 C/min02468 Heat Flow (W/g)-203080130180 Temperature ( C) Exo UpUniversal TA Instruments1151201251301350246 What is happening? Gold CKK hermetic lidExo Flow (W/g)405060708090100110120130140150160 Temperature ( C)Exo UpPOLYPROPYLENEWITH NUCLEATING AGENTSPOLYPROPYLENEWITHOUT NUCLEATING Flow (W/g)6080100120140160180200 Temperature ( C)Exo UpCrystallizationmeltingEffect of Nucleating AgentsCoolingWhat is Isothermal Crystallization?

8 A Time-To-Event ExperimentAnnealing TemperatureMelt TemperatureIsothermal Crystallization TemperatureTimeZero TimeIsothermal CrystallizationCrystallizationHeat capacity due to cooling-10123H e a t F lo w (m W )0246810121416 Time (min)TemperatureTemperature Time-to-Tmax characterizes differences A time-to-event Analysis Requires rapid cooling and equilibrationPolyethylene OxideDetermination of Crystallinity of a common Automotive Thermoplastic:PET/ABS Blend - Conventional ( C)50100150200250 Heat Flow (W/g)first heat on molded part(Curve shifted on Y axis to avoid overlap)second heat after 10 C/min C (H) mg sample, nitrogen purge 10 C/minute heating ratePET/ABS Blend - sample nitrogen purge 2 C/minute heating rate, 1 C amplitude, 60 second periodfirst heat on molded part PET TgABS Temperature ( C)4060100120140 Heat Flow (mW) ( ) Nonrev.

9 Heat Flow (W/g)( ) Rev. Heat Flow (W/g) C+ C (H) C (H)180200 Thermal and Oxidative Stability Thermal and Oxidative Stability Can be studied by multiple techniques Studied in inert or oxidizing atmospheres TGA Best starting point Weight loss or gain DSC Change in heat flow (typically exothermic) Can also see the effect in other techniqueslike DMA & TMAS tarting Point for Material Characterization First Step Thermogravimetric Analysis Look for: Thermal and Oxidative Stability Volatiles Decomposition Temperature Weight Loss Profile Number of Steps Residue Char/Ash/Filler PresenceOxidative Stability - C020406080100120 Weight (%)02004006008001000 Temperature ( C) PP Resin Nitrogen PP Resin Air Universal TA InstrumentsPolyethylene Oxidation Onset C-20-1001020 Heat Flow (mW)50100150200250300 Temperature ( C)Oxidation Onset Temperature (OOT)

10 OIT of LDPE of Cable Coatings200 200 200 200 CCCCT hermal Stability of PolymersM ethod Log: 1:Select gas: 1 - N 21: R am p C /m in to C2: Select gas: 2 - A ir3: R am p C /m in to CPVCPM M (%)502504506508501050 Temperature ( C)Block versus Random Copolymers0100200300400500050100 Temperature ( C)Weight (%)S - MSRANDOMS - MS BLOCKP - MSPS size:8 mgprog:6 C/minatm:300 Pa vacuumThermosetsThermosetsThermosetting polymers react (cross-link) irreversibly. A+B will give out heat (exothermic) when they cross-link (cure).