Differential Scanning Calorimetry DSC

Transcription

1 Analyzing & Testing Differential Scanning Calorimetry DSC Technique, Instrument, Applications DSC 3500 Sirius

2 DSC 3500 Sirius Principle of Operation Differential Scanning Calorimetry Differential Scanning Calorimetry (DSC) is one of the most frequently used techniques in the field of thermal characterization of solids and liquids. Easy handling and rapid analysis are among the hallmarks of this analytical technique, which has proven to be highly significant in the areas of research, development, and quality control. There are a variety of standards (ASTM, DIN, ISO, etc.) for the application, evaluation and interpretation of specific materials, products and properties. DSC Measurement Information < Glass transitions < Melting/crystallization behavior < Degree of crystallinity < Solid-solid transitions < Polymorphism < Cross-linking reactions < Specific heat < Purity determination < Oxidative stability < Decomposition behavior Principle of Operation In this technique, a sample is placed inside a crucible which is then placed inside the measurement cell (furnace) of the DSC system along with a reference pan which is normally empty. By applying a controlled temperature program (isothermal, heating or cooling at constant rates), caloric changes can be characterized. DSC 3500 Sirius Sturdy and Reliable The DSC 3500 Sirius combines the advantages of modern technology, high sensitivity and a robust, easy-tooperate work horse. Tests can be carried out in the temperature range between -170 C and 600 C. Key components of the DSC 3500 Sirius are the DSC heat flux sensor, the furnace and clever connection fittings which are designed for the quick and easy attachment of various cooling systems. The sensor of the DSC 3500 Sirius combines high stability and optimized resolution of thermal effects. Laserguided welding processes for the sensor disks and thermocouple wires yield true sensitivity and robustness. DSC 3500 Sirius with automatic sample changer (ASC) 2

3 Key Features of the DSC 3500 Sirius Reliable Furnace & Sensor The heating wires of the furnace surround the entire sensor plate. They are arranged in such a way that no temperature gradients occur in or above the sensor disk. This arrangement is the basis for a highly homogeneous heat flow to the sample and reference pans from all sides and therefore also for a highly stable baseline and an excellent signal-to-noise ratio. Condensation of volatiles is reduced to a minimum. Variable Gases and Cooling Options Protective and purge gas inlets are, of course, standard features of the unit. For improved cooling times and subambient temperature tests, various cooling options such as forced air, intracooler or liquid nitrogen cooling systems are available. Of course, a versatile gas switching and flow control system are also available. LN 2 inlet LN 2 outlet Scheme of the gas-tight DSC 3500 Sirius (without automatic sample changer (ASC)) Technical Key Data Temperature range -170 C to 600 C Intracooler head insert port Small gas-tight DSC cell Access window of cooling head (closed) Efficient Automatic Sample Changer Heating rates Cooling rates Sensor K/min to 100 K/min K/min to 100 K/min (depending on temp.) Heat flux system For applications with a high sample throughput, we offer an automatic sample changer (ASC) for up to 20 samples and references, which accommodates different crucible types. Measurement range ±600 mw Temperature 0.1 K Accuracy Enthalpy < 1% Forced air (RT to 600 C) Intracooler IC40 (-40 C to 600 C) Cooling options Intracooler IC70 (-70 C to 600 C) Liquid nitrogen (-170 C to 600 C) Atmospheres Oxidizing, inert (static, dynamic) ASC (optional) Robot for up to 20 samples and references 3

4 DSC 3500 Sirius _ Applications The DSC 3500 Sirius can be employed for the characterization of a great variety of materials in applications including polymers, pharmaceuticals, textiles, foods, cosmetics, inorganic materials, metals and the like. The technique employed by this instrument makes it a fast and reliable tool for researchers in fields such as automotive, clothing, drugs, and so on. Its easy operation, fast analysis time and standardized evaluation procedures also make the DSC 3500 Sirius optimal for application in quality assurance and failure analysis laboratories. Heat Capacity on Inorganic Material From Low to High Temperatures c p / J/(g K) Sapphire is a common reference material for specific heat measurements with well-proven c p data. Here, the DSC 3500 Sirius was used to determine the specific heat capacity of a sapphire disk between -140 C and 500 C. Afterwards, the heat capacity values obtained were compared with those provided by NIST (National Institute of Standards and Technology). A maximum error of 0.8% was attained over the entire temperature range Temperature [ C] C C 0.0 C C C C C C Experimental c p values [J/(gK)] c p values according to NIST [J/(gK)] Determination of the specific heat capacity of sapphire. Sample mass: mg. Crucibles: platinum with pierced lid. Temperature program: heating at 10 K/min. 4

5 Packaging Material DSC as an Identification Tool A DSC is a fast, easy-to-use instrument for the identification of materials. In the present case, three different packaging materials were measured between 30 C and 300 C at 10 K/min in two heating steps with a controlled cooling at 20 K/min in between. The 1 st heating yields information on the thermal history of a polymer; the 2 nd heating reflects its material properties. The plot on the right displays the 2 nd heating runs for each of the three samples A, B and C. Only in the DSC curves for samples A and B was a later peak also detected at 247 C and 253 C, respectively (typical melting range for different kinds of polyamide). The peak with a temperature of 159 C exhibited solely by film C is most probably attributable to the melting of polypropylene. The two peaks additionally located at 126 C and 140 C, as well as those detected in the same temperature range in the DSC curves of films A and B, are due to different polyethylene types C C C C C C C C Film A Film B Film C C C DSC measurement on 3 different polymer packaging films. Sample masses: mg (sample A), 1.45 mg (sample B), and mg (sample C); crucibles: aluminum, pierced lid. Before the 2 nd heating at 20 K/min, the sample was heated and cooled between 30 C and 300 C at 20 K/min. In the figure on the right, the advanced Peak Separation software was used to separate the three peaks detected in sample B between 100 C and 125 C. The graph shows the almost perfect correlation between the measured curve (dotted) and the sum of three calculated curves (red) with peak temperatures at 107 C, 117 C and 121 C. Such separation allows for the accurate determination of individual peak areas and temperatures. DSC/ mw/mg Measured Sum of calculated curves Curve 1 Curve 2 Curve Separation of the triple peak of sample B by means of the optional Peak Separation software. 5

6 DSC 3500 Sirius _ Applications Quality Control on Two Solders The DSC 3500 Sirius can also be used for the quality control of metal alloys. In this example, two solders made of the same material but taken from different lots were each measured two times between 25 C and 250 C. The upper plot compares the 1 st and 2 nd heating segments for the two samples. Both segments exhibit an endothermic peak (onset temperature at 217 C) which is due to the melting of the metal alloys. The melting behavior of the two lots is very similar; this is expressed not only in the shape of the curves but also in the peak temperatures and areas. 5 4 Solid Line: 1 st heating Solid Dashed: Line: 2 1 nd st heating heating J/g Peak: C Onset*: C J/g Peak: C Onset*: C J/g Peak: C Onset: C J/g Peak: C Onset*: C J/g Peak: C Onset*: C Peak: Onset: J/g C C Lot 1 Lot 2 Lot 1 Lot J/g J/g Dashed: 2 nd heating Peak: C Peak: C 1 Onset: C Onset: C 1 st and 2 nd heating segments on two solder materials. Sample mass: 6.47 mg (lot 1) and 7.05 mg (lot 2). Crucibles: Aluminum with pierced lid. Temperature program: Two heating segments up to 250 C, heating 0 and cooling rates: 10 K/min However, the two materials exhibit different cooling behavior (lower plot) after the first heating. Lot 1 (blue curve) already crystallizes at 189 C (endset), whereas lot 2 exhibits an even stronger under-cooling effect; the start of crystallization is shifted to a lower temperature (endset 187 C). This effect can be explained by differing impurity content in the two products Peak: End: Peak: End: J/g C C J/g C C Peak: End: Peak: End: J/g C C J/g C C Lot 1 Lot 2 Lot 1 Lot This example shows that the DSC 3500 Sirius is capable of performing fast quality checks. In addition, it demonstrates the importance of cooling runs especially in cases with similar heating behavior Cooling segment on two solder materials. Sample mass: 6.47 mg (lot 1) and 7.05 mg (lot 2). Crucibles: Aluminum with pierced lid. Temperature program: Two heating segments up to 250 C, heating and cooling rates: 10 K/min 6

7 Melting and Crystallization Behavior of Edible Oil The DSC 3500 Sirius is also well suited for investigations in the food industry. Presented here are the results of a DSC measurement on rapeseed oil. The sample was first cooled to -150 C and then heated to 40 C. The exothermic peak beginning at -18 C during controlled cooling at 10 K/min comes from the crystallization of the oil. The three minima at -45 C, -64 C and -69 C reflect the composition of the oil consisting mainly of oleic acid, linoleic acid and linolenic acid as well as of various saturated and unsaturated fatty acids. The additional peak detected at -4 C is probably caused by the crystallization of an additive. In the subsequent heating, crystallization occurs at -53 C, followed by the ,25-0,30-0,25-0,35-0,30-0,40-0,35-0,40 Peak*: Peak*: -0,2 J/g -3,5 C -0,2 J/g -3,5 C Temperature / C Temperature / C -3.7 J/g Peak: C -3.7 J/g Peak: C C C C C 46.9 J/g 46.9 J/g C C heating heating -0.2 J/g Peak*: -3.5 C -0.2 J/g Peak*: -3.5 C J/g C C C C J/g C C C C cooling cooling DSC measurements on rapeseed oil. Sample mass: 1.19 mg. Crucibles: Aluminum with lid. Temperature program: Cooling to -150 C, heating to 40 C, heating and cooling rates: 10 K/min melting of the components of the rapeseed oil (peak temperatures at -27 C, -18 C and -12 C). Oxidative-Induction Time (OIT) on Rapeseed Oil The oxidative-induction time (OIT) can be determined in order to estimate the relative stability of hydrocarbons to oxidation. This can be done easily with the DSC 3500 Sirius. Displayed here are measurements on rapeseed oil heated to three different temperatures under inert (nitrogen) conditions. After a five-minute equilibration time, the atmosphere was switched to air. The DSC curves show the influence of the test temperature on the degradation of the samples. Degradation began earlier at higher temperatures: It took 63 min under oxidizing conditions at 140 C, but only 4 min for the test carried out at 180 C Dashed: DSC signal under nitrogen Continuous: DSC signal under air Dashed: DSC signal under nitrogen Dotted: Temperature signal Continuous: DSC signal under air Dotted: Temperature signal Temp./ C Temp./ C OIT: 4.2 min OIT: 63.3 min 120 OIT: 13.1 min OIT: 4.2 min OIT: 63.3 min OIT: 13.1 min Time /min Time /min DSC measurements on rapeseed oil. Sample mass: 1.19 mg. Crucibles: Aluminum with lid. Temperature program: Cooling to -150 C, heating to 40 C, heating and cooling rates: 10 K/min, isothermal temperatures: 140 C (green), 160 C (blue) and 180 C (red)

8 DSC 3500 Sirius _ Proteus Software and Accessories Software The DSC 3500 Sirius runs on a Windows operating system and includes everything you need to carry out a measurement and evaluate the resulting data. User-friendly menus combined with automated routines make Proteus very easy to use while providing sophisticated analysis. Key Features of the General Software Software produced by iso-certified company NETZSCH for Windows, XP and Windows 7 operating systems Simultaneous measurement evaluation Operation of with one computer Combined analysis and different instruments of DSC, TGA and TMA and DMA measurements Input and free placement of text elements Calculation of 1 st and 2 nd derivative Selectable colors and line types restoration of analyses Storage and Context-sensitive help system Results by Automatic detection of instrument settings (e.g., furnace, sensor, etc.) Data export in Excel -compatible CSV-format Calibration and for temperature, sensitivity, baseline Picture-in-picture presentation (PIP/FLIP) correction routines Key Features of the Proteus Software for DSC Glass transitions Comprehensive analysis of Peak/peak search, selectable baseline Partial peak area Transition enthalpies: Analysis of peak area (enthalpies) with selectable baselines Automatic baseline correction Degree of crystallinity Specific heat determination c p (optional) Tau-R Mode: takes into account the time constant and thermal resistance of the instrument and thus reveals sharper DSC effects from the sample (optional) Liquid fraction, BeFlat for (optional) OIT evaluation Monitoring of Simultaneous analysis curves Re import of solid fat index (SFI) baseline optimization all MFC gas flows of multiple measurements saved as ASCII files Temperature-modulated DSC (optional) Advanced Software (optional) Peak Separation for accurate separation and evaluation of overlapping transitions NETZSCH Thermokinetics for advanced characterization of reactions and kinetic parameters also provides predictions of the process 8

9 DSC Accessories The DSC 3500 Sirius can be equipped with various accessories and add-ons for optimum adjustment of the system to your requirements. Various cooling systems can be used to cool the furnace back to room temperature. Subambient temperatures (down to -70 C) can be achieved with the cost-effective Intracooler. The liquid nitrogen cooling system allows tests at subambient temperatures down to -170 C. The DSC 3500 Sirius can be equipped with a gas flow control system for precise control of up to three different purge/protective gases. Routine measurements are facilitated with the convenient automatic sample changer (ASC) for up to 20 samples and references, even in different crucible types. A wide range of crucibles (aluminum, silver, gold, copper, platinum, alumina, zirconia, graphite, stainless steel, etc.) is available for nearly all possible applications and sample materials. The SampleCutter is ideal for the preparation of polymer samples; it allows for defined cuts for generating plane sample surfaces. SampleCutter Medium-pressure crucible (left) and high-pressure crucible (right) Al crucibles with lids Sealing press for different aluminum crucible types 9

10 Expertise in Service Our Expertise Service All over the world, the name NETZSCH stands for comprehensive support and expert, reliable service, before and after sale. Our qualified personnel from the technical service and application departments are always available for consultation. In special training programs tailored for you and your employees, you will learn to tap the full potential of your instrument. Summary of Our Services Installation and commissioning Hotline service Preventive maintenance Calibration service IQ / OQ / PQ On-site repairs with emergency service for NETZSCH components Moving / exchange service Technical information service Spare parts assistance To maintain and protect your investment, you will be accompanied by our experienced service team over the entire life span of your instrument. 10

11 Our Expertise Applications Laboratories The NETZSCH Thermal Analysis applications laboratories are a proficient partner for nearly any Thermal Analysis issue. Our involvement in your projects begins with proper sample preparation and continues through meticulous examination and interpretation of the measurement results. Our diverse methods and over 30 different state-of-the-art measuring stations will provide ready-made solutions for all your thermal needs. Within the realm of thermal analysis and the measurement of thermophysical properties, we offer you a comprehensive line of the most diverse analysis techniques for materials characterization (solids, powders and liquids). Measurements can be carried out on samples of the most varied of geometries and configurations. You will receive high-precision measurement results and valuable interpretations from us in the shortest possible time. This will enable you to precisely characterize new materials and components before actual deployment, minimize risks of failure, and gain decisive advantages over your competitors. For production problems, we can work with you to analyze concerns and develop solutions. The minimal investment in our testing and services will reward you with reduced down time and reject rates, helping you optimize your processes across the board. 11

12 The NETZSCH Group is a mid-sized, family-owned German company engaging in the manufacture of machinery and instrumentation with worldwide production, sales, and service branches. The three Business Units Analyzing & Testing, Grinding & Dispersing and Pumps & Systems provide tailored solutions for highest-level needs. Over 3,000 employees at 163 sales and production centers in 28 countries across the globe guarantee that expert service is never far from our customers. When it comes to Thermal Analysis, Calorimetry (adiabatic & reaction) and the determination of Thermophysical Properties, NETZSCH has it covered. Our 50 years of applications experience, broad state-of-the-art product line and comprehensive service offerings ensure that our solutions will not only meet your every requirement but also exceed your every expectation. NETZSCH-Gerätebau GmbH Wittelsbacherstraße Selb Germany Tel.: Fax: at@netzsch.com NGB DSC 3500 Sirius EN LH Technical specifications are subject to change.