Thermoanalytical Methods: Lecture 1 PDF

Lecture Lectureoutline outline Thermoanalytical Analytical methods: review Thermogravimetry: TGA TGA: Applications DMA Evolved gas analysis: EGA DSC Thermoanalytical techniques Lecture 1 Module: PHCO-3309 (Pharmaceutical materials science) Dr. I.Ermolina DMU Dr. Ermolina Lecture 1: PHCO-3309 PHAR 34...

Lecture Lectureoutline outline Thermoanalytical Analytical methods: review Thermogravimetry: TGA TGA: Applications DMA Evolved gas analysis: EGA DSC Thermoanalytical techniques Lecture 1 Module: PHCO-3309 (Pharmaceutical materials science) Dr. I.Ermolina DMU Dr. Ermolina Lecture 1: PHCO-3309 PHAR 3403?? Lecture Lectureoutline outline Thermoanalytical Analytical methods: review Thermogravimetry: TGA TGA: Applications DMA Evolved gas analysis: EGA DSC Overview Module: PHCO-3309 (Pharmaceutical materials science) Learning materials (Dr Ermolina): Thermoanalytical techniques - Seminar (3 lectures) (Term 1) Excipients Biological materials DMU (Term 1) (Term 1 and 2) (4 lectures) (Term 2) (2 lectures) Dr. Ermolina Lecture 1: PHCO-3309 PHAR 3403?? Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA 3 Lectures outline Learning objectives for 3 Lectures Brief overview of thermoanalytical methods: materials and applications To describe the basic principles and instruments for thermoanalytical techniques: TGA, EGA (1st Lecture) TMA, DMA, DTA, DSC (2nd Lecture) DSC Applications (3rd Lecture) To discuss the choice of parameters, limitations of the methods and sources of errors for each method To guide in the use these techniques for analytical problems solving: some examples DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Lecture 1 outline Learning objectives for Lecture 1 Thermal analysis and thermoanalytical methods: overview of techniques, materials and applications Description and the basic principles of the Thermogravimetrical Analysis (TGA): - Balances - Furnaces - Sensitivity - Sources of errors Applications for TGA Evolved Gas Analysis (EGA): principals and applications DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Definition Thermal analysis is defined by ICTAC (International Confederation for Thermal Analysis and Calorimetry) as “a group of techniques in which a property of the sample is monitored against time or temperature while the temperature of the sample, in a specified atmosphere, is programmed. The program may involve heating or cooling at a fixed rate of temperature change holding the temperature constant any sequence of these.” DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA DMU Thermoanalytical techniques Property measured Technique Acronym Lecture Mass Thermogravimetry or Thermogravimetric analysis TG TGA (L1) Volatiles Evolved Gas Analysis EGA (L1) Temperature Differential Thermal Analysis DTA (L2) Heat or heat flux Differential Scanning Calorimetry DSC (L2, L3) Mechanical properties Thermomechanical Analysis Dynamic Mechanical Analysis TMA DMA (L2) Dimensions Thermodilatometry TD (L2) Acoustical properties Thermosonimetry, Thermoacoustimetry Electrical properties Thermoelectrometry Magnetic properties Thermomagnetometry Optical Thermooptometry Radioactive decay Emanation Thermal Analysis Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Overview A large variety of thermoanalytical techniques for materials characterization and analysis Old methods existed for some hundred years (TG, DTA, dilatometry) New methods - computer-controlled instruments - with data processing - sample handling capabilities Thermoanalytical methods are versatile (variety of methods) Methods can be combined (the same sample, single measurements, simultaneous methods) (TG+DTA) DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Materials and Applications Materials Aplications Technology Composition Content Purity Content and influence of fillers Effect of moisture Storage stability Safety Investigation Process control DMU Chemical changes Decomposition Pyrolysis Oxidation Stability Reaction process Reaction enthalpy and kinetics Curing Vulcanization Phase changes Melting/Crystallization Vaporization Drying Adsorption Polymorphism Crystalline transitions Glass transition Liquid-crystalline transitions Physical properties Specific heat capacity Expansion coefficient and behaviour Viscoelastic behaviour Elastic modulus Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Applications The materials studied include Applications Materials’ characterization, Polymers Material analysis, Pharmaceuticals Quality control Ceramics Process control Metals Alloys DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Thermogravimetry (TG) TG is one of the basic methods in thermal analysis. In TG the variation in mass of sample is measured as a function of Temperature (or Time) in a controlled atmosphere. This variation in mass can be either a loss of mass (vapor emission) or a gain of mass (gas fixation). TG was originally developed by K.Honda in 1915, then it has been greatly improved: - sensitivity - automatic recording of Dm vs. T curve - controlling of the instrument (heating rate, atmosphere) TG determines - sample purity, - decomposition behaviour, - chemical kinetics DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Example of thermogram Decomposition of Calcium Oxalate mass 100 Ca(C2O4)H2O Calcium oxalate monohydrate 200 300 400 500 600 700 800 900 - H2O Ca(C2O4) Calcium oxalate - CO carbon monoxide CaCO3 Calcium carbonate - CO2 carbon dioxide CaO Calcium oxide DMU Dr. Ermolina Lecture 1: PHCO-3309 ToC Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Thermogravimetry (TG) The essential components of TG include: balance thermobalance furnace sample chamber instrument control/data handling Furnace Programmer Controller Balance mass Data Acquisition and Handling S DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Purged gas (N2, He,..) Real instrument: TG-1 Balance Contra weight Sample Furnace Sample chamber (glassy tube) DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Sensitivity A sensitive and reliable analytical balance is a central part of TG instrument Sensitivity typically in the order of 1mg Actual weight of sample is from 10 to 50 mg TG instrument companies are former or present balance manufacturers DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Types of balances Several types of balance mechanism : Beam spring Cantilever Torsion balance Null-point weighing mechanism - sample always remains in the same heating zone Elecromagnetic balances - relatively insensitive for vibration - high sensitivity (up to 0.1 mg) - thermal stability DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: The furnace Temperature range of a furnace depends mainly on the materials used for its construction For range from 25oC up to 1000 - 1100oC (Fused quartz tubes + Kanthal-type heating-element materials) For range from 25oC up to 1500 – 1700oC (Ceramic refractories such as alumina or mullite) Most thermobalance manufacturers offer instruments which can reach 1500oC. Above 1500oC there are material problems with heating element, furnace construction, thermocouples (for To measurements) DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: The furnace There are 3 main possibilities to place the sample relative to the balance and furnace There is no contact between sample holder and furnace !!! Sample furnace (a) Horizontal Balance (b) Top-loading (c) Suspended DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Instrument control and data handling Modern features In nowadays the PC has been incorporated into most commercially available instruments to take care of - the heating and cooling cycles - data storage - handling To resolve overlapping thermal reactions - the 1st derivative of Dm vs. T (DTG) curve is calculated - isothermal heating or very slow heating rate is used - in quasi-isothermal TG (high resolution or controlled-rate TG) the heating slowed down when a weight change begins DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Applications Drying/water content mass - Bulk water A - Absorbed water - Constitutional water (Crystalline water) Different types of water are expelled at different temperatures. D A− D )  100% => Water/moisture content = ( A DMU Dr. Ermolina Lecture 1: PHCO-3309 temperature Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Derivative curve Most instruments also record the Derivative Termogravimetry (DTG) curve, which is the rate of the mass change dm/dt = f(T). The area under the DTG curve is proportional to this mass change The DTG mass losses are plotted downward mass gains are plotted upward. TG DTG The maximum (or minimum) of DTG curve corresponds to a point of inflection in TG curve at which mass is lost (or gained) more rapidly. A better distinguish of overlapped steps is obtained with DTG. The height of DTG peak at any temperature gives the rate of mass change. DMU Dr. Ermolina Lecture 1: PHCO-3309 IP Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Application Copper Sulfate Penta Hydrate CuSO4 x 5H2O There are three endothermic processes: at 75oC, 113oC, 250oC: 1 –1st step: 13.97% lost mass - 2 H2O – 2nd step: 13.35% lost mass - 2 H2O – 3rd step: 7.03% lost mass - 1 H2O 2 Area under DTG ~ Dm TGA DTG DMU 3 Copper has 4 or 6 coordinates. 4 molecule of water are connected directly to copper ion, 5th is connected in different manner in crystal lattice. Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Sources of error Several factors influence the correctness of the measured mass and temperature. These factors arise from TG instruments, experimental parameters of sample and parameters of experiment: Amount of material Heating rate Pan type Gas flow (atmosphere) Most factors can be controlled for their influence DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Sources of error Major factors affecting the recorded mass (m) and temperature (T) in TG: Electrostatic effects (m) Condensation and reaction (m) Buoyancy (m) Heating rate (T) Gas flow (T) Sample holder (T) Reaction enthalpy (T) Sample size and packing (T) DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Sources of error Effect of sample holder geometry Fig. 7.5-5. Influence of the sample holder geometry on the decomposition of calcium carbonate (CaCO3): CaCO3 => CO2+CaO [Paul Gabbott, 2007, Principles and Applications of Thermal Analysis] DMU Dr. Ermolina Lecture 1: PHCO-3309 16 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Applications Effect of purged gas Analysis of coal with TG (oC) 105 950 700 Gas change Mass, % moisture furnace off volatiles Oxidation of fixed carbon ash nitrogen oxygen Time DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA TG: Applications Analysis of coal with TG Initially the heating is carried out in an inert atmosphere (N2) => amount of moisture and volatiles are measured At fixed temperature the thermo-balance automatically switches the atmosphere into an oxidazing atmosphere => carbon is burnt => carbon and ash content The accuracy of results obtained by TG is comparable with another method requiring much more manual work DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Handling of sample TA Tip on the sample robot (for TGA and DSC) TGA and DSC experiments are very long => losing moisture or => absorption of water For large series of samples => Sample Changers. Samples store at the turntable sample robot Advantages: - Preparation of set of samples at the same time - Overnight (weekend) measurements Two ways: Automatic loading Automatic open DMU 1. Samples are hermetically sealed and lid is pierced just before measurement 2. Samples are stored in ceramic crucible and lid is removed just before experiment Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Evolved gas analysis (EGA) EGA Evolved gas analysis (EGA) is a method used to study the gas evolved from a heated sample that undergoes decomposition or desorption. It is possible to detect which gas is evolved using evolved gas detection (EGD). EGD is often performed by coupling EGA with Mass Spectrometry (MS), Fourier transform infrared spectroscopy (FTIR) or Gas Chromatography (GC). DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Evolved gas analysis (EGA) A simultaneous TG-MS-EGA for Calcium Oxalate CaC2O4.H2O TG DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA Companies Thermo-analytical Instrumentation Companies: PerkinElmer, USA, Mettler Tolledo, Switzerland. Since the early 1960s SETARAM Instrumentation, France and many more… DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA References References for Lecture 1, Lecture 2 and Lecture 3: Analytical chemistry. Edited by R.Kellner, J.-M.Mermet, M.Otto, H.M.Widmer. WILEY-VCH. Paul Gabbott, 2007, Principles and Applications of Thermal Analysis http://us.mt.com/mt_ext_files/Editorial/Generic/8/TA_UserCom20_EditorialGeneric_1116417553558_files/tauserc20e.pdf http://pslc.ws/macrog/dsc.htm http://www.perkinelmer.com/CMSResources/Images/44-74556GDE_TGABeginnersGuide.pdf http://vedyadhara.ignou.ac.in/wiki/images/1/1c/UNIT_10_THERMOGRAVIMETRIC_ANALYSIS.pdf http://depts.washington.edu/mseuser/Equipment/RefNotes/TGA_Notes.pdf http://www.perkinelmer.com/CMSResources/Images/44-74542GDE_DSCBeginnersGuide.pdf http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2977967/ DMU Dr. Ermolina Lecture 1: PHCO-3309 Lecture outline Thermoanalytical methods: review Thermogravimetry: TGA TGA: Applications Evolved gas analysis: EGA The end The end DMU Dr. Ermolina Lecture 1: PHCO-3309