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TA Instruments User Training DSC原理與應用 2012年9月7日 國立台灣大學化學系 潘貫講堂 (B棟積學館2樓演講廳) 基礎原理 許炎山 TA Instruments, Waters LLC 美商沃特斯國際股份有限公司台灣分公司 TA Taipei office: 104臺北市長安東路1段23號4F之5 Tel: 02-25638880 C/P: 0928-168676 Fax: 02-25638870 E/M : jhsu@tainstruments.com 何謂熱分析 (Thermal Analysis)? 性質 搜集物質的物理特性隨著控制溫度(環境)或時間變化下所相應的 函數關係之技術稱為“熱分析”. 溫度 何謂熱分析 (Thermal Analysis)? O2 Heating Melting Oxidation heat capacity expansivity modulus melting point crystallinity softening purity OIT stabilizers burning profile low Temperature Decomposition temperature content kinetics high 何謂熱分析 (Thermal Analysis)? Material Properties Melting point / melting range Crystallization behavior Glass transition temperature Coefficient of thermal expansion Thermal stability Decomposition temperatures and kinetics Oxidation induction time / temperature , OIT Crosslinking behavior Purity Visco-elastic properties: modulus, damping and creep Swelling behavior Thermal Conductivity Thermal Diffusivity 何謂熱分析 (Thermal Analysis)? Chemical Reactions and Properties Reactions between components in the formulation or the atmosphere Effect of catalysts Chemical bonding of plasticizers Crosslinking reactions Chain scission Oxidative reactions Degradation breakdown Molecular structure and bond strengths Chemical weather and ageing effects Effect of additives Polymerizations 何謂熱分析 (Thermal Analysis)? Physical Properties Specific heat capacity Physical transitions Mass or weight changes Mechanical properties such as dimension, deformation, storage and loss modulus Thermal Conductivity / Thermal Diffusivity Nature of evolved gas 何謂熱分析 (Thermal Analysis)? Industry Research & Development Quality Control Service Labs Academia Application Food Cosmetics Forensics Textiles Electronics Automotive Aerospace Packaging Biochemistry Polymers Biopolymers Ceramics Metal Composites Adhesives Paints Lacquers Resins Pharmaceutical … 何謂熱分析 (Thermal Analysis)? Polymers Glass transition Crystallization Melting Degradation Oxidation Phase transitions Compatibility Identification Polymers Polyolefins Resins Adhesives Blends Composites Paints 何謂熱分析 (Thermal Analysis)? Pharmaceuticals Polymorphism Crystallization Phase transitions Identification of components Compatibility Stability Purity Binary phase diagrams Moisture Drugs Drug delivery systems Excipients Manufacturing additives Packaging materials 何謂熱分析 (Thermal Analysis)? Cosmetics Formulation Compatibility Stability Polymorphism Glass transition Crystallization Raw material identification Organic content Pigment color analysis Water content Lipsticks Fats Waxes Creams Nail varnish Polymer packaging 何謂熱分析 (Thermal Analysis)? Food Polymorphism Identification of components Crystallization Thermal history Stability Glass transition Vaporization Denaturizing Visco-elastic behavior Swelling Edible fats and oils Fatty acids Cocoa butter Starch Sugar Proteins 何謂熱分析 (Thermal Analysis)? Petrochemicals and Organic Chemicals Identification of components Crystallization Phase transitions Binary phase diagrams Polymorphism Hazard analysis Oxidation stability Explosives Lubricants Paraffin Waxes Pitches Liquid Crystals Oils 何謂熱分析 (Thermal Analysis)? Inorganics Glass transition Crystallization Melting Degradation Oxidation Reaction Phase transitions Compatibility Water determinations Calibration standards Carbonates Cement Coal Fillers Hydrates Gypsum Metals and alloys Glass Ceramics Minerals DSC: The Technique Differential Scanning Calorimetry (DSC) measures the temperatures and heat flows associated with transitions in materials as a function of time and temperature in a controlled atmosphere. These measurements provide quantitative and qualitative information about physical and chemical changes that involve endothermic or exothermic processes, or changes in heat capacity. DSC: What DSC Can Tell You Glass Transitions Melting and Boiling Points Crystallization time and temperature Percent Crystallinity Heats of Fusion and Reactions Specific Heat Oxidative/Thermal Stability Rate and Degree of Cure Reaction Kinetics Purity DSC: Definitions A Calorimeter measures the heat into or out of a sample. A Differential Calorimeter measures the heat of a sample relative to a reference. A Differential Scanning Calorimeter does all of the above and heats the sample with a linear temperature ramp. Endothermic heat flows into the sample. Exothermic heat flows out of the sample. DSC: Heat Flow/Specific Heat Capacity ΔH = Cp ΔT or in differential form dH/dt = Cp dT/dt + thermal events Cp = specific heat (J/g°C) T = temperature (°C) H = heat (J) dH/dt = heat flow (J/min.) mW = mJ/sec dT/dt = heating rate (°C/min.) assuming work & mass loss are zero DSC 是熱分析家族的入門基礎 兩大主流: 熱流式 Heat Flux DSC 補償式 Power Compensated DSC Perkin Elmer introduced the Power Compensation DSC 1 in 1966 Dupont introduced the Heat Flux DSC 10 in 1968 電能補償式 Power-Compensation Principle Sample Platinum Alloy Reference PRT Sensor Platinum Resistance Heater Heat Sink PE Produced Information When an exothermic or endothermic change occurs in the sample, power(energy) is applied or removed from the furnace to compensate for the energy change occurring in the sample. The system is maintained in “Thermal Null” state all the time. The amount of power required to maintain the system in equilibrium is directly proportional to the energy changes. Typical Power Compensation DSC Cell Sample Furnace Sample Reference Furnace ΔT (ΔP) Insulating Heat Sink Reference Platinum Resistance Thermometers (PRT) Platinum Resistance Thermometers(PRT) =Sample Temperature Power Compensation Baseline Curvature (Best case scenario) 7 Heat Flow in mW 6 5 Baseline run to run (SB1) Y value @ 140蚓 4 first heat = 5.750 mW second heat = 5.730 mW third heat = 5.730 mW fourth heat = 5717 mW fifth heat = 5.732 mW sixth heat = 5.789 mW 3 2 1 baseline, run to run: SB1A2.DCD Heat Flow in mW: Step: 2 baseline, run to run: SB1A2.DCD Heat Flow in mW: Step: 8 baseline, run to run: SB1A2.DCD Heat Flow in mW: Step: 10 baseline, run to run: SB1A2.DCD Heat Flow in mW: Step 14 baseline, run to run: SB1A2.DCD Heat Flow in mW: Step 18 baseline, run to run: SB1A2.DCD Heat Flow in mW: Step 22 0 50 100 150 200 250 300 350 Sample Temperature in 蚓 400 450 熱流式 Classical DSC: Measurement of HF and Sample Ref constantan Cu-Ni chromel alumel Ni-Cr Ni-Al Platinel Control Thermocouple Ag furnace DSC: Temperature Measurement Sample Sample Temperature Ts Ref Furnace Temperature Tc DSC: Heat Flow Measurement Sample Ref Potential Difference ΔU Temperature Difference ΔT Heat Flow dQ/dt DSC: How Heat Flux is Measured • Heat flow through the chromel wafer causes a temperature difference ΔT. The temperature difference is measured as the voltage difference ΔU between the sample and reference constantan/chromel junctions. The voltage is adjusted for thermocouple response S and is proportional to heat flow. ΔT = ΔU / S ΔT in °C ΔU in µV S in µV/°C 傳統熱流式 DSC 運作邏輯示意圖 Metal 1 Metal 2 Sample Temperature Metal 1 Metal 2 Triac Board Referance Temperature Temperature Difference = Heat Flow Main CPU Board ΔH = Cp ΔT or in differential form dH/dt = Cp dT/dt + thermal events where: Cp = specific heat (J/gOC) T = temperature (OC) H = heat (J) dH/dt = heat flow (J/min) mW = mJ/sec dT/dt = heating rate (OC/min) assuming work & mass loss are zero Controller Classical Heat Flux DSC, TA Instruments DSC 10 DSC 910 DSC 920 DSC 2010 DSC 2910 DSC 2920 Gas Purge Outlet Sample Pan Reference Pan Gas Purge Inlet Constantan Disc Chromel Disc Chromel Disc Sample Thermocouple Reference Thermocouple Silver Furnace TA Instruments DSC 2XXX DSC 2010 DSC 2910 DSC 2920 TA Instruments DSC Q Series Q1000/Q2000 Q100/Q200 Q10/Q20 TA Instruments DSC 電腦控制技術的進展 Dupont Controller 9900 + 獨立interface + X-Y Plotter IBM TA2000/RMX + 獨立interface + X-Y Plotter/IBM Printer IBM TA4000/OS2 + 內建interface + Printer PC TA5000/Windows +內建interface + 各種圖譜輸出功能 PC TA Advantage/Windows +內建interface + 全方位輸出功 能 獨立 interface : DSC 10/910/920 內建 interface : DSC 2010/2910/2920/Q Series 內建工作站 : Discovery DSC Heat Flux DSC: Theoretical ΔT Measurement Temperature ΔT Tr = Reference Temperat Ts = Sample Temperature To = Onset of Melt Tp = Peak of Melt To Tp Time Theoretically: To = Tp 157.5 157.5 157.0 157.0 ΔT 156.5 156.5 Slope due to thermal lag 156.0 156.0 5.2 5.3 5.4 5.5 Time (min) 5.6 5.7 5.8 Reference Temperature (蚓 ) Sample Temperature (蚓 ) Actual Heat Flux Data Actual Heat Flux Data 157.5 157.5 157.0 -2 156.5 156.5 -4 156.0 156.0 5.2 Exo Up 5.3 5.4 5.5 Time (min) 5.6 5.7 5.8 Reference Temperature (蚓 ) 157.0 Delta T/Heat Flow SampleTemperature (蚓 ) 0 Conventional DSC Measurements Heat Flow Measurement Model Heat Balance Equations qs = T fs − Ts Rs qr = T fr − Tr Rr Conventional DSC Heat Flow Rate Measurement q = q s − qr Tr − Ts − ΔT = q= R R This model assumes that the sample and reference calorimeter thermal resistances are identical, the temperature of the furnace at the sample and reference calorimeters are equal and does not include other known heat flows. Assumptions Achieved Through Mechanical Means z Uniform Furnace Temperature z High Conductivity Silver Furnace z Uniform Thermal Resistance zMechanical Symmetry z Differential Temperature zSeries Opposed Thermocouple System Other Assumptions Cs = Cr Ms = Mr Cps = Cpr Mps = Mpr Rd is very large Rps = Rpr and is very small Symmetry is Assumed, Rarely Achieved • The heat flow rate of an empty perfectly symmetrical twin • • calorimeter should be zero. However it almost never is because the DSC is rarely symmetrical as assumed. The asymmetry is the inevitable result of manufacturing tolerances and is practically unavoidable. For example, thermal resistance of the Tzero ® DSC cell is determined by the wall thickness of the “top hat” which is 0.127 mm. To achieve 1% thermal resistance imbalance would require a manufacturing tolerance of 0.00127 mm. Why Tzero® ? • To remove the erroneous contribution to the thermogram from the calorimeter itself. Q Series Tzero® Transducer (2001) Reference Platform Sample Platform Chromel Area Detector Thin Wall Tube Constantan Body Constantan Wire Chromel Wire Chromel Wire Q-Sries New Tzero™ DSC CELL SCHEMATIC Tzero™ SENSOR Sample Platform Chromel Area Detector Reference Platform New Chromel/Constantan Tzero™ sensor located midway between the sample and reference platforms. Tzero™ sensor acts as control sensor to assure precise isothermal furnace operation. The Tzero™ sensor is also used to calculate the four term heat flow. Constantan Body Thin Wall Tube Base Surface Constantan Wire Chromel Wire Chromel Wire Tzero Thermosensitive Area In the TA Instruments design, the entire surface of the sample and reference platform represents thermosensitive area. This area is roughly 17.8 mm2 The chromel-constantan thermocouple is a high-ouput device Thermosensitive area detector Tzero Principle of Operation Tf Rs Ts Cs Rr To Tr The Tzero™ thermocouple provides an objective reference point so that those factors previously assumed can be directly measured. Cr Tzero™ DSC Measurement Model Heat Flow Sensor Model Heat Balance Equations qr dTs T0 − Ts qs = − Cs Rs dτ qs Cs Cr Ts Tr Rs Rr T0 qr = T0 − Tr dT − Cr r Rr dτ Tzero® Heat Flow Equation Tzero Heat Flow Equation ΔT dTs d ΔT ⎛1 1⎞ q=− + ΔT 0 ⎜ − ⎟ + ( Cr − Cs ) − Cr ΔT ΔT = T - d Tτ Rr= T – T ⎝ Rs Rr &⎠ dτ s • • • • r 0 0 s Principal DSC Heat Flow Thermal Resistance Imbalance Heat Capacity Imbalance Heating Rate Difference Tzero™ Heat Flow Term Contributions Principal heat flow provides main heat flow signal Thermal resistance and heat capacity imbalance terms improve baseline Heating rate difference term improves resolution and MDSC performance ⎛ 1 dTs dΔ T ΔT 1 ⎞ q=− + ΔT0 ⎜⎜ − ⎟⎟ + (Cr − Cs ) − Cr Rr dτ dτ ⎝ Rs Rr ⎠ What is Pan Contact Resistance? DSC Pan Imperfect (non-intimate) contact between pan and sensor causes lag in heat flow which decreases resolution Heat Flow Heat Flow Sensor Incorporating Pan Contact Resistance A model was derived which incorporates pan contact resistance into the heat flow equation qsam mprcpan mpscpan Pan Tpr Tps Rp qs Sensor Ts Rp Cr Cs Rs qr Tr Rr T0 Tzero® Benefit: Improved Baseline Shape ΔT dTs d ΔT ⎛1 1⎞ q=− + ΔT 0 ⎜ − ⎟ + ( Cr − Cs ) − Cr Rr dτ dτ ⎝ Rs Rr ⎠ 150 Heat Flow (μW) 100 50 0 -50 -100 -150 -100 Heat Flow T1 µW Heat Flow T4 µW 0 100 200 Temperature (°C) 300 400 Tzero® Benefit: Improved Peak Resolution ΔT dTs d ΔT ⎛1 1⎞ + ΔT 0 ⎜ − ⎟ + ( Cr − Cs ) − Cr q=− Rr dτ dτ ⎝ Rs Rr ⎠ 1 0 Heat Flow (W/g) -1 -2 -3 -4 -5 Heat Flow T1 -6 -7 -8 150 152 154 156 158 160 Temperature (°C) 162 164 Advanced Tzero™ Results Advanced Tzero DSC 1.13 mg Dotriacontane 10蚓 /min 0 Heat Flow (mW) -5 -10 -15 Advanced Tzero Tzero DSC Conventional DSC -20 -25 61 65 69 Temperature (蚓 ) 73 77 Discovery DSC Objective But, Tzero is only as good as the measured signals: ΔT, ΔT0 & Ts The objective of the Discovery DSC Technology is to realize the full potential of the Tzero® method by dramatically improving the measured signals New Sensor - Objectives Improve sensor flatness to reduce pan/sensor contact resistance variations Reduce distortion due to thermal expansion difference between chromel area thermocouples and constantan platforms Realize full benefit of Tzero sample pans – reduce pan contact resistance and variation Pan Contact Resistance New Sensor - Objectives Optimize thermocouple location Thermocouple should not be in pan/sensor contact zone because inevitable variations in the magnitude and distribution of contact resistance reduces the repeatability of the differential temperature measurements Locate thermocouple so that ΔT and ΔT0 measurements are unaffected by pan contact resistance variations Discovery DSC Transducer High strength bond Improved flatness of pan/sensor contact region by 6x No alloying of thermocouple by welding • Optimum thermocouple placement: junction at circumference Time Constant Comparison 1 0.9 T1 Normalized Heat Flow 0.8 Normalized Heat Flow Q2000 T4P Normalized Heat Flow 0.7 Discovery DSC Normalized Heat Flow T4P 0.6 0.5 0.4 Discovery DSC Time Constant: ~0.8 s 0.37 0.3 0.2 0.1 0 0 1 2 3 4 5 Time (sec) 6 7 8 9 10 Indium Response Ratio 2 Heat Flow (mW) 0 -2 Q20: 8 Q2000: 60 -4 -6 Discovery DSC: >90 -8 -10 -12 152 153 154 155 156 157 158 159 Temperature (°C) 160 161 162 163 Q SERIES AUTOLID AND TOUCH SCREEN Autolid – automates placement and removal of DSC lids and thermal shields providing repeatable thermal isolation of the cell. Integrated Touch Screen – for local control and monitoring of experiment, real time signals, and time remaining. Automatic autosampler calibration is initiated from this screen. MASS FLOW CONTROLLER z Accurate, settable purge gas flow that eliminates flow meters z Settable in method z Includes gas switching z Easy to use Legris fittings Autolid II Design Improvements Redesigned Autolid II Easier adjustment Better lid placement precision More efficient purge gas exhaust Better Temperature/Tzero Stability Tzero™ DSC CELL SCHEMATIC Silver Base for Cell Lid #1 Silver Base for Cell Lid #2 Chambers for Temperature Conditioning of Purge Gas Measuring Chamber Furnace Tzero™ Sensor 54 Nickel Cooling Rods Cooling Flange COOLING OPTIONS : FACS Finned Air Cooling System (FACS) – Innovative (silent!) system that uses house air to cool the DSC to ambient temperatures. Can be used for cooling experiments, and thermal cycling. Cost effective alternative to Refrigerated and Liquid Nitrogen systems for work at ambient temperatures and above. LIQUID NITROGEN COOLING SYSTEM Temperature range = -180 to 550 °C Cooling Rates = 85 °C/ min to 100 °C = 50 °C/min to 0 °C = 25 °C/min to – 100 °C Baseline Bow = <30 μW (-100 to 300 °C) Baseline Repeatability = < 40 μW Baseline Noise = < 1.5 μW p-t-p COOLING OPTIONS : RCS Refrigerated Cooling System (RCS) RCS90 can achieve lower temperatures (-90C). RCS40 can achieve lower temperatures (-40C). Q SERIES AUTOSAMPLER Ultra-reliable autosampler with patented new optical sensor. Compatible with multiple pan types. Works perfectly with all automated cooling systems. Self calibrating. Q SERIES Pressure DSC Pressure Cell 1. Q20 PDSC 2. Q1000/Q2000 PDSC Q SERIES Photo-DSC Q SERIES Optical-DSC This hole is sized to the probe diameter. Universal Optical Accessory Kit NIR, RAMAN
