Method and apparatus for large scale differential scanning calorimetry analysis

Abstract

According to the present application, there is provided a method of differential scanning calorimetry and an apparatus for power compensated differential scanning calorimetry, the method comprising: Heating and / or cooling the samples and reference materials; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change and / or based on a difference in the temperature and / or the temperature change between the sample and the reference material; determining at least one thermodynamic property of the sample and / or composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; The process includes the steps of: In the method, the sample is heated and / or cooled at a first sample side, and the temperature and / or the temperature change of the sample is determined at a second sample side opposite the first sample side, and The reference material is heated and / or cooled at a first reference side and the temperature and / or the temperature change of the reference material is determined at a second reference side opposite the first reference side.

Description

[Technical field]

[0001] The present disclosure relates to the determination of thermodynamic properties of substances, such as calorimetry, particularly differential scanning calorimetry, more particularly power compensated differential scanning calorimetry. The present disclosure further relates to material analysis and identification, particularly of polymers. [Background technology]

[0002] Differential scanning calorimetry ("DSC") is an analytical technique for determining the heat capacity of a substance, in particular its specific heat capacity and specific enthalpy, and / or for determining material properties such as glass transition temperature, melting, crystallization, hardening process, purity, oxidation behavior, and / or thermal stability. In DSC, the heat flow into and out of a sample undergoing a temperature change is measured relative to a reference material.

[0003] In general, DSC techniques can be divided into "heat flux DSC" and "power compensation DSC" (sometimes called "power balanced DSC"). Heat flux DSC is concerned with the detection of the temperature difference between the sample and the reference as a function of the heating power. Conversely, power compensation DSC is concerned with the detection of the difference in the thermal effect from the heating power between the sample and the reference as a function of temperature. In power compensation DSC, the sample and the reference are heated in separate sample vessels, and the heating power to each vessel is controlled and adjusted to minimize the temperature difference between the sample and the reference due to the difference in heat capacity. Typically, the sample heats and / or cools slower than the reference, and a corresponding adjustment of the heating / cooling power to the sample is required to obtain the desired temperature path of both the sample and the reference, which is a measure of the heat capacity difference. The reference can be a material that is substantially inert over the temperature range of interest. It should be noted that in experiments spanning a large temperature range, multiple reference materials may be used to interrogate several different intervals of the temperature range.

[0004] For example, various aspects of DSC are discussed in E.S. Watson et al., “A differential scanning calorimeter for quantitative differential thermal analysis”, Anal.Chem.36(7): 1233-1238 (1964); K.V.Kodre et al., “Differential scanning calorimetry: a review”, Res.and Rev.: J.Pharma.Anal.3(3): 11 -22 (2014); and J.Drzezdzon et al., “Characterisation of polymers based on differential scanning calorimetry based techniques”, Trends Anal.Chem.110:51-56 (2019). Aspects of (power compensated) DSC and the determination of heat flow to a sample in a DSC are further disclosed in U.S. Pat. No. 6,428,230, U.S. Pat. No. 6,497,509, U.S. Patent Application Publication No. 2007 / 0286769(A), German Patent Application Publication No. 102015217636(A1), and U.S. Patent Application Publication No. 2020 / 0124548.

[0005] A general emphasis with known power compensated DSC methods and apparatus is to keep the sample size as small as possible to minimize temperature gradients in the sample and / or for rapid temperature changes. Summary of the Invention [Problem to be solved by the invention]

[0006] There is a continuing need for more accurate determination of thermodynamic properties of substances, such as phase changes, and / or more accurate identification of substances based on small differences in thermodynamic properties. In addition, there is a need for accurate analysis of large samples, potentially large volumes of samples, compared to the current milligram or microgram dimensions. [Means for solving the problem]

[0007] In view of the foregoing, there is provided herein a method of differential scanning calorimetry and an apparatus for power compensated differential scanning calorimetry.

[0008] The method comprises: Heating and / or cooling the samples and reference materials; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change and / or based on a difference in the temperature and / or the temperature change between the sample and the reference material; determining at least one thermodynamic property of the sample and / or a composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; Includes.

[0009] In the method, the sample is heated and / or cooled at a first sample side, and the temperature and / or the temperature change of the sample is determined at a second sample side opposite the first sample side, and The reference material is heated and / or cooled at a first reference side and the temperature and / or the temperature change of the reference material is determined at a second reference side opposite the first reference side.

[0010] Thus, the method comprises: heating and / or cooling the sample at a first sample side and determining the temperature and / or the temperature change of the sample at a second sample side opposite the first sample side; and heating and / or cooling the reference material at a first reference side and determining the temperature and / or the change in temperature of the reference material at a second reference side opposite the first reference side. Includes.

[0011] The heating and / or cooling of the reference material and the determination of the associated temperature and / or temperature change may be performed independently or at least partially simultaneously with the heating and / or cooling of the sample, this latter option may be preferred taking into account possible small deviations in the equipment employed.

[0012] The method may include power compensation DSC, which includes controlling the heating and / or cooling power to the sample and controlling the heating and / or cooling power to the reference so as to minimize the difference in the temperature and / or the temperature change between the sample and the reference. This may be done in particular when both the sample and the reference undergo a predetermined temperature change, in particular the same predetermined temperature change, at least a part of which may preferably be linear with respect to time. In this method, unlike known DSC methods, by determining the temperature and / or temperature change of the sample on the opposite side to its heating and / or cooling, relatively large samples may be investigated and the resolution of thermal behavior (e.g. detection of enthalpy change) may be enhanced even for large samples.

[0013] In the method, a sample heater may be placed in close thermal contact with the sample, or even in direct contact with the sample, to heat the sample, which may provide an improvement over current DSC mechanisms where the sensor is placed between the heater and the sample, such that heat from the heater must pass through a temperature sensor to heat the sample, or where heating of the sample is indirect, such as in Tian-Calvet type mechanisms.

[0014] Furthermore, the heat flow through the sample and / or reference material, respectively, may be determined, which may allow separate and possibly complementary measurements in parallel.

[0015] The method is generally scale-free and may allow for the determination of one or more thermodynamic properties of large samples. In the method, compensation for known heating gradients may be achieved.

[0016] Additionally or alternatively, the method enables a new form of differential scanning calorimetry, heat flow DSC, in which, unlike conventional power-compensated DSC, the heating and / or cooling power to the sample (and / or to the reference, respectively) is controlled as a function of the heat flux through the sample (and / or through the reference), rather than as a function of absolute temperature difference and / or difference in temperature change (or rate of temperature change).

[0017] Since thermodynamic properties, especially (specific) heat capacity, tend to be substance specific, comparing the determined thermodynamic properties with reference values ​​may allow the identification of the sample substance and / or its composition, for example differences between (the properties of) polyethylene and polypropylene and / or other polymers may be easily detectable.

[0018] The method may include determining at least one of a temperature and a temperature change of the sample at the first sample surface and / or determining at least one of a temperature and a temperature change of the reference material at the first reference material surface.

[0019] This allows for averaging of the detected temperature and / or temperature changes across the sample, which may improve the determination of the temperature and / or temperature changes of the sample. This is similarly true for the reference material. Such improved determination of both the sample and the reference material provides additional benefits to the method as a whole.

[0020] Furthermore, this improves the accuracy of the determination of the heat flow through the sample by comparing the temperature and / or the temperature change at the first and second sample surfaces. This is similarly true for the reference material. Such improved accuracy for both the sample and the reference material provides additional benefits to the method, particularly heat flow DSC.

[0021] As mentioned above, in some cases it may be preferable to omit a temperature sensor on the first sample side, but this is believed to be outweighed by the increased accuracy and / or flexibility of the method when temperature and / or temperature changes are determined on both sides of the sample. This also applies to the reference material.

[0022] Further provided is a method of differential scanning calorimetry, possibly in combination with any of the methods disclosed herein, comprising: Heating and / or cooling the samples and reference materials; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change and / or based on a difference in the temperature and / or the temperature change between the sample and the reference material; determining at least one thermodynamic property of the sample and / or a composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; The process includes the steps of: Here, the sample is heated and / or cooled at a first sample side and the reference is heated and / or cooled at a first reference side.

[0023] The method may include determining at least one of a temperature and a temperature change of the sample at a plurality of positions on the first sample surface and / or of the reference at a plurality of positions on the first reference surface. Additionally or alternatively, the method may include determining at least one of a temperature and a temperature change of the sample and / or the reference at a plurality of positions on each second surface (i.e., the second sample surface and / or the second reference surface, respectively).

[0024] For example, the sample temperature and / or reference temperature may be determined using a temperature detector, which may comprise a single sensor configured to determine temperature and / or temperature difference as a function of position, and / or multiple sensors, which may be arranged in a regular or irregular array, which may allow simultaneous detection at multiple locations and prevent time differences. Additionally or alternatively, a thermal camera may be used as a sensor to determine temperature and / or temperature change as a function of position at multiple locations in parallel. A suitable thermal camera may be responsive to infrared light, and possibly also to visible and / or ultraviolet wavelengths.

[0025] This facilitates averaging of the temperature and / or temperature change over at least a portion of the sample and / or reference material. This may improve accuracy by preventing local variations from affecting the measurement. For example, it may simplify taking into account non-uniform occurrences of one or more of heat radiation, convection, or conduction.

[0026] However, in addition or alternatively, this facilitates one or more location-specific determinations. Such spatially resolved determinations may provide information about one or more of the differences and / or changes in the device used to perform the method, for example in the case of differences in thermal connection with a heater. In addition or alternatively, such spatially resolved determinations may provide information about local differences in the properties and / or behavior of the sample, for example local heat flow differences. Such differences may indicate differences in the composition and / or homogeneity of the sample, which may be a signal of impurities and / or density irregularities in the sample.

[0027] In any of the methods herein, the sample may have a size in a first dimension that is at least one order of magnitude smaller, preferably multiple orders of magnitude smaller, than in the second dimension, and possibly at least one order of magnitude smaller, preferably multiple orders of magnitude smaller, than in the third dimension.

[0028] And the first and second faces of the sample may be opposite each other in the first dimension. The same may be true for the reference material. Preferably, the sample and reference material have the same shape and / or size in at least the first dimension, and preferably also in one or both of the second and third dimensions.

[0029] Thus, the sample may be elongated and / or preferably plate-like. By providing the sample in such a shape and providing the determination in the first dimension, providing at least part of the analysis may be generally scale-free in the second and third dimensions, particularly when temperature gradients in the second and / or third dimensions are absent or at least significantly smaller than in the first dimension.

[0030] The magnitude in at least the first dimension may be determined as a function of one or more of the thermal material properties, heating rate, and required sensitivity of the sample being investigated.

[0031] In at least the first dimension, the size and / or shape of the sample may be constant, and / or the first and second faces may be parallel to each other. A constant size and / or shape in one or more dimensions may prevent effects of size changes and / or artifacts. For example, this may facilitate comparison of detection results at multiple locations in a spatially resolved measurement.

[0032] It should be noted that for different samples, especially samples of different materials and / or different compositions, the sample container may be replaced. Additionally or alternatively, different reference materials may also be used, the choice of which may depend on one or more (expected) sample properties.

[0033] In any method herein, at least a portion of the sample may be placed in an upright sample container, and the first and second sample surfaces may be defined by horizontally opposite sides of the sample container. Additionally or alternatively, at least a portion of the sample may be received in a sample container that is liquid-tight to hold a liquid sample portion. Similarly, at least a portion of the reference material may be placed in an upright reference material container, and the reference material container may be liquid-tight to hold a liquid reference material portion, and the first and second reference material surfaces may be defined by horizontally opposite sides of the reference material container.

[0034] At least a portion of the sample may be provided as one or more objects, for example in the form of one or more chunks, pieces, flakes, etc., and / or in granular form, which may include particulate powder.

[0035] Any of the methods herein may include melting at least a portion of the sample and determining the heat flow through the sample horizontally and / or in a direction parallel to the level of the melted sample material, e.g., parallel to the average position of the liquid meniscus.

[0036] In that way, the heat flow through the sample and sample vessel can be determined without disturbance of the sample surface and gas barriers. The sample can take the shape of the sample vessel, particularly if the sample is one or more of granular, at least partially liquid, and / or liquefied.

[0037] In particular in the case of a sample provided as one or more bodies, e.g. in flake and / or granular form, the method may comprise flowing a gas, in particular an inert gas, over and / or through at least a portion of the sample, possibly at least in part during heating and / or cooling of the sample.

[0038] This allows the removal of substances that may become dissociated from the sample material and / or that may evaporate. Additionally or alternatively, by appropriate selection of and / or control over the composition of the gas, chemical reactions of the sample material, such as oxidation, may be caused or even prevented.

[0039] Any of the methods herein may include controlling the heating and / or cooling power to provide a predetermined heating and / or cooling rate of the sample and / or the reference material.

[0040] Any method herein may include providing a modulation to the heating and / or cooling power to the sample and / or the heating and / or cooling power to the reference material to impart a predetermined heating rate modulation to the sample and / or the reference material, which may result in a temperature modulation and / or a temperature change modulation (varying rate of temperature change). The modulation, e.g., heating rate modulation, may be periodic, e.g., the heating rate modulation may take the form:

[0041]

number

[0042] The method may include detecting one or more of hysteresis of at least one thermodynamic property of the sample, a phase change in the sample, a chemical reaction in the sample, and an irreversible change in the sample. Such detection may be based on a difference between one or more reversible and one or more irreversible signal components in at least one of sample temperature, sample temperature change, and heat flow through the sample. The detection may include lock-in detection of the heating rate modulation and temperature detection (of one or more temperature sensors) and / or it may include performing a Fourier transform on at least one of the heating rate modulation, the heating and / or cooling power to the sample and / or the reference material, the sample temperature, sample temperature change, and heat flow through the sample, the reference material temperature, reference material temperature change, and heat flow through the reference material.

[0043] In connection with any embodiment of the method, there is provided herein an apparatus for power compensated differential scanning calorimetry.

[0044] In particular, the device comprises: a sample container for holding a sample; a reference material and / or a reference material container for holding the reference material; a sample heater and a reference heater; a sample temperature detector for determining the temperature and / or temperature change of the sample; a reference temperature detector for determining the temperature and / or temperature change of the reference; a controller configured to control heating and / or cooling power to the sample and to control heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change and / or based on a difference in the temperature and / or the temperature change between the sample and the reference material; It is equipped with:

[0045] In the apparatus, the sample heater is configured to heat and / or cool the sample at a first sample side, and the sample temperature detector is configured to determine a temperature and / or a temperature change of the sample at a second sample side opposite the first sample side; The reference material heater is configured to heat and / or cool the reference material at a first reference material side, and the reference material temperature detector is configured to determine the temperature and / or temperature change of the reference material at a second reference material side opposite the first reference material side.

[0046] For example, the sample heater is disposed on a first sample side, the sample temperature detector is disposed on a second sample side opposite the first sample side, the reference heater is disposed on a first reference side, and the reference temperature detector is disposed on a second reference side opposite the first reference side; heating and / or cooling the sample at the first sample side and the reference at the first reference side; The temperature and / or the temperature change of the sample at the second sample surface is determined, and the temperature and / or the temperature change of the reference at the second reference surface is determined.

[0047] Such an apparatus would facilitate implementing the methods described herein, and it could provide power-compensated DSC with improved accuracy.

[0048] The heater controller may be connected to the sample heater and / or the reference heater, or to a sample heater controller and / or a reference heater controller. Additionally or alternatively, the heater controller may be connected to the sample temperature detector and / or the reference temperature detector. Thus, direct interaction of the controller with the operation of the device may be facilitated.

[0049] The sample vessel may be provided with walls of relatively high thermal conductivity, e.g. metal walls, on the first and / or second face. On one or more other faces, the sample vessel may be provided with one or more insulating walls, e.g. made of a polymeric material, e.g. a material having a thermal conductivity of less than k=0.2, preferably less than 0.1, more preferably less than 0.05, and / or having a thermal conductivity of less than 50%, preferably less than 30%, more preferably less than 20%, e.g. less than 10% or even less than 5% of the expected thermal conductivity of the sample material. The lower the thermal conductivity, the better the insulation of the sample material from the space surrounding the sample vessel and therefore the more accurate the measurements can be, because the heat entering the sample from the heater cannot flow out of the sample at such a face, and therefore the heat flow is better guided from the first face to the second face.

[0050] The device may be configured for contact heating of the sample vessel by the heater, e.g. the heater is in contact with the sample vessel without a gas layer between the heater and the sample vessel. The same may be true for (contact) heating of the reference material.

[0051] The sample heater and / or the sample temperature detector may be connected to or part of the sample container. For example, the sample heater may define and / or provide a sidewall of the sample container. Similarly, the reference heater and / or the reference temperature detector may be connected to or part of the reference container.

[0052] The device may comprise a further sample temperature detector arranged at the first sample surface for determining the temperature and / or temperature change of the sample, and / or a further reference temperature detector arranged at the first reference surface for determining at least one of the temperature and / or temperature change of the reference. Such a device allows the determination of a thermal gradient across the sample and / or the reference. This facilitates the determination of the heat flow through the sample and / or the reference.

[0053] Further provided herein is an apparatus for power compensated differential scanning calorimetry, the apparatus comprising: a sample container for holding a sample; a reference material and / or a reference material container for holding the reference material; a sample heater and a reference heater; a sample temperature detector for determining the temperature and / or temperature change of the sample; a reference temperature detector for determining the temperature and / or temperature change of the reference; a controller configured to control heating and / or cooling power to the sample and to control heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change and / or based on a difference in the temperature and / or the temperature change between the sample and the reference material; At least one of the sample temperature detector, further sample temperature detector, reference temperature detector, and further reference temperature detector may comprise a sensor configured to determine temperature and / or temperature differential as a function of position and / or a plurality of temperature sensors at a plurality of positions on each of one or more of the first sample surface, second sample surface, first reference surface, and second reference surface, wherein one or more of the plurality of temperature sensors may be or comprise a sensor configured to determine temperature and / or temperature differential as a function of position.

[0054] The detector may comprise an optical detector, e.g. a thermal camera, by which at least a portion of the sample container and / or reference material may be imaged. Fiber optic detectors, e.g. comprising distributed Bragg reflectors, may also allow position sensitive detection.

[0055] An apparatus with such a detector comprising multiple sensors may be configured such that one or more signals of at least some of the multiple sensors are detectable together, e.g., for purposes of signal enhancement and / or averaging. Additionally or alternatively, such an apparatus may be configured such that one or more signals of at least some of the multiple sensors are detectable individually and / or as subgroups of each of the multiple temperature sensors, e.g., for location-specific and / or spatially resolved determinations.

[0056] At least one of the detectors and / or the controller may enable selection between collective detection, individual detection, and / or subgroup-based detection of each sensor.

[0057] Thermocouples, thermistors, thermopiles, bolometers, fiber optic detectors, alone or in any suitable combination, may form suitable sensors.

[0058] In the device, the first and second sides of the sample vessel may be opposite each other in a first dimension, and the sample vessel may have a size in the first dimension that is at least one order of magnitude smaller, preferably multiple orders of magnitude smaller, than in the second dimension, and possibly at least one order of magnitude smaller, preferably multiple orders of magnitude smaller, than in the third dimension.

[0059] The same may apply mutatis mutandis to the reference material and / or the reference material container.

[0060] The sample vessel and / or the reference vessel may comprise an upright sample vessel defining the first and second surfaces as upright surfaces on generally horizontally opposite sides of the sample vessel. Additionally or alternatively, the sample vessel may be liquid-tight to retain a liquid sample portion, e.g. a liquefiable fraction of the sample.

[0061] At least a portion of the sample may be provided as one or more objects, e.g. in granular form, including in particulate powder form, and the determination, e.g. a determination of heat flow, may be performed horizontally and / or in a direction parallel to the filling height of the granular sample material.

[0062] The apparatus may include a sample oven and a reference oven, the sample oven including the sample container, the sample heater and one or more of the sample temperature detectors, and the reference oven including the reference material and / or the reference container, the reference heater, and one or more of the reference temperature detectors.

[0063] The sample oven and the reference oven should preferably be thermally insulated from each other, and more preferably substantially thermally independent from each other, so that heating and / or cooling of one of the sample and the reference does not affect, or at least does not substantially affect, the heating and / or cooling of the other of the sample and the reference (i.e., other than (the effect of) controlled heating and / or cooling of one based on the temperature and / or temperature change of the other, as foreseen in the method discussed herein). Thermal interaction between the ovens other than through the controlled heating and / or cooling for the DSC may degrade the accuracy of detection and should therefore be reduced or prevented. Although in some cases it may be preferable to physically separate the ovens, it may be practical to combine both ovens as separate compartments in a single housing.

[0064] The apparatus may comprise a sample chamber housing the sample vessel and a gas and / or vacuum system connected to the chamber for controlling at least one gas property, such as gas pressure, gas composition and / or gas humidity, gas temperature, and gas flow around and / or through at least a portion of the sample vessel. The sample chamber may be the sample oven.

[0065] Similarly, the apparatus may comprise a reference chamber housing the reference container, and a gas and / or vacuum system connected to the chamber for controlling at least one of gas composition and / or gas humidity, gas temperature, gas flow around and / or through at least a portion of the reference container. The reference chamber may be the reference oven.

[0066] In the sample chamber and / or the reference chamber, respectively, the gas system may be configured to control the gas in one or both of the respective chambers (e.g., by varying the gas composition and / or gas humidity and / or gas temperature), for example in terms of gas flow rate and / or rate of change of one gas property relative to another gas property.

[0067] The above-described aspects will be further explained below together with additional details and advantages with reference to the drawings, which show, by way of example, several embodiments. [Brief description of the drawings]

[0068] [Figure 1] FIG. 1 shows a plate-shaped sample. [Diagram 2] FIG. 2 shows a portion of an apparatus for power compensated differential scanning calorimetry in accordance with the principles of the present invention. [Diagram 3] FIG. 3 shows a portion of a detector with multiple sensors. [Figure 4] FIG. 4 shows details of an embodiment with a heater. [Diagram 5] FIG. 5 illustrates in some detail schematic form some of the elements of an exemplary embodiment of the apparatus and the relationships between them. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] It is noted that the drawings are schematic and not necessarily to scale, and that details not necessary for understanding the invention may be omitted. The words "above," "below," "below," "on top," and the like refer to the embodiments oriented in the drawings, unless otherwise specified. Furthermore, elements that are at least substantially identical or perform at least substantially the same functions are represented by the same numerals and, where useful, differentiated by alphabetical suffixes.

[0070] Further, unless otherwise specified, terms such as "detachable" and "removably connected" are intended to mean that the respective parts can be separated essentially without damaging or destroying either part, and exclude structures where the parts are integral (e.g., welded or molded as one piece), but include structures where the parts are attached by or as such, mating connectors, fasteners, releasable automatic fastening features, etc.

[0071] FIG. 1 shows a graph of a volume L with a first dimension Z. Z and a thickness of 0.01 mm and a size L X and L Y The sample 1 is shown in the form of a plate having a length and width of L (see also the reference coordinate system in the figure). The thickness of the sample 1 is several orders of magnitude smaller than the width and height, respectively. Z may be in the range of 1-25 mm, in particular in the range of 2-20 mm, more in particular in the range of 3-15 mm, preferably in the range of 4-10 mm, e.g. in the range of 5-7 mm. Thinner samples, e.g. having a thickness in the range of 2-5 mm, may improve local precision, but at the cost of averaging over the sample size. Also, inclusions, density variations, and / or impurities may be best detectable in samples having a thickness of about 4-6 mm, whereas thicker samples may allow for bulk analysis. The lateral dimensions (X, Y dimensions) may be chosen at will, so long as they are preferably sufficiently larger than the direction of heat flow, such that (undesirable) non-uniform heating and / or edge effects can be neglected and / or the heat flow is at least primarily in the first dimension.

[0072] In use, the sample 1 is heated and / or cooled at a first sample side S1. A temperature T1 and a temperature T2 of the sample 1 can be determined at the first sample side S1 and at a second sample side S2 opposite the first sample side S1, respectively.

[0073] For DSC measurements of finite duration on a sample, it is desirable to minimize thermal gradients in the sample (or more precisely, the sample and the sample vessel holding the sample). Consider the incompressibility of the volume given by:

[0074]

number

[0075]

number

[0076] Without wishing to be bound by any particular theory, in simplified form, in the concepts presented herein, assuming uniform heating of the sample 1 at the first surface S1 and neglecting non-equilibrium effects, the governing equation is:

[0077]

number

[0078]

number

[0079]

number

[0080] By inducing a known and constant heat flow through the sample, the heat capacity of the material, c p and the effect of the phase change f(T,t) of the material can be determined. Thus, from Equation 3, the following can be derived:

[0081]

number

[0082] As a result,

[0083]

number

[0084] Extending the above to time-dependent behavior gives us:

[0085]

number

[0086] And since the heat that flows in is absorbed by the mass of the sample,

[0087]

number

[0088]

number

[0089] This is the heat capacity c p , the phase transition reaction f(T,t), and the enthalpy per temperature step ∂ T Give H.

[0090] Note that the concept is inherently scale-free dependent on a specified volume V0. Thus, both high-volume DSC or very sensitive nano-DSC can be realized within the concept. Furthermore, the better the ΔT, ρ, k, and L of the sample are known, the better the phase change response f(T,t) can be determined.

[0091] The preceding comments regarding the sample also apply equally to the reference material according to FIG.

[0092] FIG. 2 shows a part of an apparatus 10 for power-compensated differential scanning calorimetry. The apparatus comprises a sample chamber 11 in the form of a thermally isolated oven. The apparatus 10 may comprise a reference chamber 12 containing a reference material R (shown only roughly), which may be substantially identical to the sample chamber 11, in which case the word "sample" below may be understood to be replaced or replaceable by "reference material". It is noted that in addition or alternatively, the apparatus 10 may comprise one or more further sample and / or reference chambers, which may be substantially identical to the sample chamber 11. The more similar the chambers are, the easier and / or better the measurements in such chambers may be comparable and the more accurate the results may be.

[0093] The sample chamber 11 is shown comprising a sample container 13 for holding a sample 1, a sample heater 15 and a sample temperature detector 17 for determining the temperature and / or temperature change of the sample 1. The sample temperature detector 17 comprises a number of temperature sensors 19, each connected to a heater controller 21.

[0094] The temperature sensor 19 may comprise, for example, one or more of a thermocouple, a temperature dependent resistor, and an infrared camera. For some measurements, a determination of a specific temperature may be required or desired, for other measurements, a determination of a change in temperature may be sufficient.

[0095] Spaces between adjacent sensors 19 may be left free or, as shown, may be provided with a mounting frame 23, which may comprise insulation of insulating material, that supports and / or positions the sensors 19. Additionally or alternatively, (the insulation of) the mounting frame 23 may reduce or prevent thermal differences due to gas turbulence and / or gas flow along at least a portion of the sample chamber 11 and / or radiation losses from the sample chamber 11.

[0096] FIG. 3 shows that within the detector 17, the sensors 19 are preferably arranged in a regular array within the frame 23.

[0097] The sample vessel 13 is oriented upright as shown, and the first and second surfaces S1, S2 may be defined as upright surfaces on generally horizontally opposite sides of the sample vessel 13. Preferably, the sample vessel 13 is liquid-tight to retain a liquid sample portion, e.g. a liquefiable fraction of the sample.

[0098] The sample heater 15 is configured to heat and / or cool the sample 1 at the first sample surface S1, and the sample temperature detector 17 is configured to determine the temperature and / or temperature change of the sample 1 at the second sample surface S2 opposite the first sample surface S1.

[0099] The sample heater 15 may comprise a heating element, a cooling element or both heating and cooling elements, which may be integrated, all of which may comprise electric heaters such as current loops, induction heaters etc., conduits for flowing hot and / or cold gases and / or liquids, thermoelectric elements such as Peltier elements etc., see also below. One or more radiative heating elements such as infrared emitters and / or microwave emitters may also be used. The combination of heating and cooling elements simplifies and / or increases the control over the temperature established by the heater and / or the heat transferred to the sample 1, especially in the case of different size scales and / or heating / cooling power scales, for example to achieve a uniform temperature distribution (in the X and Y directions in Figs. 1-2) over the heated sample surface.

[0100] The device 10 may comprise a weight sensor, such as a balance, for determining the weight of the sample. The weight sensor may be included in the sample chamber and / or sample container and / or configured for repeated determination, such that the weight change of at least a part of the sample and / or the reference material may be determined, possibly in relation to the temperature and / or temperature change of at least a part of the sample and / or the reference material. Such a device may in particular (also) be used for Thermo-Gravimetric Analysis (TGA).

[0101] FIG. 4 shows a detail of an embodiment with a heater 15, which optionally has a heater surface S 15 The sample heater 15 may comprise a combination of a first heater 15A for uniformly heating the sample or other heated object and a number of second heaters 15B for additional localized heating or cooling of the sample or other heated object. For example, the sample heater 15 may comprise a layered structure with a first layer 25 forming the first heater 15A and a second layer 27 on top of the first layer constituting the second heater 15B, the layers may or may not have the same size. The first layer 25 may comprise a stack of materials with different thermal conductivities for uniform temperature and / or heating over the heating surface (X and Y directions), for example a metallic layer with a relatively high thermal conductivity followed by a metallic and / or non-metallic layer with a relatively low thermal conductivity. The second layer 27 may comprise a number of separate heaters 15B, e.g. thermoelectric heaters, e.g. Peltier elements, one or more of which may be controlled individually and / or as groups, which may facilitate or simplify providing controlled heating and / or variations in heating that may be related to local properties of the sample, such as local variations in density and / or composition relative to one or more other locations in the sample.

[0102] Optionally, the spaces between the second heaters 15B may be filled with a material having a relatively high thermal conductivity in order to prevent possibly steep temperature gradients between the local heaters 15B and / or optionally a further layer 29 having a relatively high thermal conductivity may be provided. It is noted that such a function of a third layer may be provided by part of the wall portions W1, W2 of the sample vessel 13.

[0103] In an apparatus 10 having a locally controllable heater 15, such as the heater 15 of FIG. 3, the location of at least some of the temperature sensors 19 of the temperature detector 17 may correspond to the location of at least some of the locally controllable heating positions, for example, sensor positions are aligned with the second heater 15B. Additionally or alternatively, the temperature sensors 31 of the temperature detector 17 may be aligned rather with positions between the second heaters 15B, and / or other temperature sensors 33 of an additional temperature detector 34 may be placed directly between the second heaters 15B. Temperature sensors 31, 33 directly opposite each other may increase sensitivity to heat flow, and locating at least some temperature sensors 33 between the second heaters 15B may provide temperature detection on the heater side without requiring heat flow through the sensors 33 from the heater 15 to the sample 1.

[0104] Referring again to Fig. 2, the apparatus 10 comprises a controller 35 connected to the sample heater 15 and the sample temperature detector 17. The controller 35 is also connected to the reference chamber 12 (the heater and temperature detector). The controller 35 is configured to control the heating and / or cooling power to the sample 1 and to control the heating and / or cooling power to the reference R based on the difference in temperature and / or the temperature change between the sample 1 and the reference R. While the controller 35 can be a dedicated device, at least a part of the controller can be a computer adapted to carry out the steps of the methods disclosed herein and / or to perform calculations using the formulas disclosed herein.

[0105] The apparatus 10 further comprises an optional gas handling system 37 connected to the chamber for controlling at least one of the gas composition and / or gas humidity, gas temperature, and gas flow through the chamber 11 around at least a portion of the sample vessel 13, and additionally or alternatively through the sample vessel 13 and the sample material therein. Typically the gas is air, or preferably nitrogen and / or another inert gas or gas mixture.

[0106] The chamber may be evacuated by an optional vacuum system to obtain vacuum insulation of the sample container and sample, which in Fig. 2 is integrated into the gas handling system 37 as a further option. The gas handling system 37 may comprise one or more gas sources (e.g. tanks), a gas dehydration and / or humidification system, a gas mixing system, pressure regulation, etc. (not shown). The gas handling system may also comprise one or more gas heaters and / or gas coolers, which may comprise one or more heat exchangers and / or one or more vortex tubes. Optionally, the gas handling system 37 is connected to the controller 35 and / or the controller 21 to control the gas handling and / or the temperature of the gases.

[0107] The gas handling system 37 and at least a portion of the chamber may be closed so that the gas is not added to the apparatus and / or lost from the apparatus and / or added during a measurement, which would otherwise cause changes to the system and affect measurement accuracy. Also, some volatile substances from the sample may be harmful to operators and / or the environment if proper measures are not taken.

[0108] 5 illustrates in some detail and generally the relationships between some of the elements of an exemplary embodiment of the apparatus 100. The apparatus 100 includes two substantially identical and identically operated chambers 110, 112, one for a test sample and one for a reference sample.

[0109] Associated with each chamber 110, 112, the apparatus includes a heater having a heating element and a heating and cooling system 115, 116 connected to control system electronics in a heater controller. The heaters are connected to a power source 140 to provide heating power. The heating and cooling systems 115, 116 are optionally provided with a common cooling system 142. The cooling system may be or include a compressed air cooling system that may provide an air flow to the heaters and / or may include vortex cooling. It is noted that gas vortex cooling may also provide a hot gas flow that may be used to heat at least a portion of the apparatus.

[0110] Associated with each chamber 110, 112, the apparatus includes a sample vessel 113, 114, preferably with metal plating on each opposing side wall associated with the heater and temperature detector, and with insulating material on the wall defining the other side of the sample vessel;

[0111] An optional gas cleaning system 144 (which may optionally be connected to and / or integrated with the heating system and / or the cooling system) is provided and may be used to provide a nitrogen flow through the chambers 110, 112 and / or sample vessels 113, 114 and the samples (or reference samples) contained therein.

[0112] An optional vacuum pumping system 146 is provided for at least partially evacuating one or both chambers 110, 112. Given time and / or pumping power, the vacuum may reach pressures below 10 kPa, preferably below 5 kPa, more preferably below 1 kPa, or even lower, such as below 500 Pa or even lower. Vacuum levels may be determined for removal of gases and / or volatiles, possibly including boiling off impurities and / or contaminants from the sample and / or sample chamber contents, and / or to provide insulation of the sample from surrounding walls and / or other objects.

[0113] For temperature detection of the sample and reference materials, each chamber 110, 112 is provided with a sensor array 117, 118 of a plurality of temperature sensors mounted on a mounting that may be formed as a frame. The sensors may be configured for data recording and / or wireless transmission of data and / or they may be connected to one or more signal conductors, such as conductors mounted on a circuit board and / or cables that are heat resistant and should prevent thermal effects, such as outgassing of insulating materials, for example electrical insulation may be provided by a relatively inert material, such as glass and / or ceramic beads around the conductors.

[0114] Further, readout electronics 119, 120 are provided in connection with the temperature sensors. The readout electronics 119, 120 include data acquisition ("DAQ") components, possibly connected to a printed circuit board ("PCB") supporting other electronic components. One or more sensors of the sensor array 119 are configured to provide analog signals, and may be, for example, thermistors and / or thermocouples, which may be noise-resistant and / or may eliminate the need for an energy source for the sensors. For data acquisition, one or more analog-to-digital converters may be used. It is noted that other sensors may also be provided, for example, one or more temperature and / or temperature change sensors arranged in the chamber without direct (thermal and / or physical) contact with the sample holder and / or sample, such as (infrared and / or visible radiation) cameras, gas pressure detectors, gas composition detectors.

[0115] During operation, heat from the heater flows into the sample chamber, in particular the sample vessel and sample contained therein. Data indicative of the temperature of the sample is measured using the temperature sensor. The measured data is transmitted as a data signal to the readout electronics, which converts the data into temperature data, which data (converted or not) is then transmitted to a computer and / or microcontroller 148 (and / or any other suitable controller), acting as the controller of the device, for (further) conversion and / or calculation and / or control using the data. The computer and / or microcontroller is also connected to the heater and transmits and / or receives control and / or operational data to / from the heater. At least a portion of the data and / or other data received at and / or transmitted from the computer and / or microcontroller, e.g. data indicative of the status of the operation and / or temperature program of the device, may be displayed on an optional display 150.

[0116] Similarly, due to the same arrangement and operation, at least a portion of the data signals, temperature data, control data and / or operational data from the second chamber may be received by and / or transmitted from the computer and / or microcontroller 148 and displayed on the optional display 150.

[0117] Any controller of the apparatus described herein, in particular the computer and / or microcontroller, may comprise a memory for storing and / or retrieving a computer program containing instructions that cause the apparatus 100 to perform one or more steps of the method.

[0118] The computer and / or microcontroller 148 may also be connected to a gas cleaning system 152, which may be enclosed and / or part of a gas handling system, which also includes the vacuum system 146 and / or the compressed air cooling system 144 and / or a further sample container gas system.

[0119] Such a gas cleaning system 152 may comprise one or more of a mass flow controller 154 for evaluating at least a portion of the gas flow from and / or to the chamber, a heating and / or cooling element 156 for heating and / or cooling at least a portion of the gas (however, the gas flow may additionally or alternatively pass through the heating / cooling system 115), a sample chamber 158 and / or sample container (connection to), and a gas purification system, e.g., physical and / or chemical filters, which may include an activated carbon filter 160 for purifying (filtering) at least a portion of the gas, possibly arranged in a loop as shown.

[0120] In general, a DSC measurement may involve providing the sample to be tested as particulate matter, e.g., a powder, to the sample container and placing the sample container in the sample chamber. A reference material of suitable configuration is placed in the reference chamber. The reference material may be a specific object and / or a specific filling of the reference container. The sample and reference chambers and the sample and reference containers may be identical to each other and derive their respective identities as "sample chamber" / "reference chamber" and "sample container" / "reference container" simply as provisional labels from the nature of the contents of each container.

[0121] The sample and reference chambers are then gas flushed and evacuated one or more times, including passing a gas flush through the sample vessel (the sample in it) to remove, for example, (water) vapour and / or other volatiles. Gases that have passed through the chambers and / or samples may be subjected to treatment and / or investigation to determine the chemical composition and / or chemical reactions and / or mass loss of the sample. Additionally or alternatively, the mass of the sample may be determined on a balance.

[0122] The sample and reference are then subjected to a temperature program involving controlled heating and also controllable cooling over a temperature range, which may span several hundred Kelvin. During the temperature program, the heating and / or heating rate, and the temperature and / or the temperature change of the sample and the reference may be determined, the heating and / or heating rate of the sample may be controlled relative to the (heating and / or heating rate of) the reference by controlling the heating and / or cooling power to the sample heater, and the relatively higher or lower power required to change the sample temperature by a particular amount compared to the same temperature change of the reference may be determined by the specific heat capacity c of the sample. p and / or one or more phase changes f(T,t). During such a temperature program, gas flushing, including preferably treatments and / or investigations, such as those described above, may also be used.

[0123] One or more such "runs" (runs of such a temperature program) may be performed in succession, with a first run being used to set up, condition, and / or otherwise prepare the sample for one or more subsequent runs. During at least a portion of the first run, a gas flushing control may be performed to remove gases and / or volatiles from the sample and / or sample chamber (this may also be done for the reference and / or reference chamber, although this may not be necessary if sufficiently inert). During and / or after subsequent runs, the chamber may be evacuated and / or pressure controlled. The temperature programs of multiple runs on the sample may be different or the same. Differences may be in the temperature ranges covered, and / or different rates of temperature change in one or more parts of the temperature range, any of which may be used for detailed study of specific effects, with a slower heating rate (slower increase in the sample temperature) increasing the heat capacity c of the sample. p and / or may lead to increased sensitivity to (the effects of) changes in the phase change f(T,t).

[0124] The computer and / or microcontroller heating the sample from a first predetermined temperature to a second predetermined higher temperature, e.g., a maximum temperature, at a predetermined heating rate; maintaining the sample at this second predetermined temperature for a first predetermined time, e.g., a predetermined number of minutes, to obtain a homogenous temperature throughout the sample, at least some and / or a portion of the sample chamber, heater, and sensor; cooling the sample again at a predetermined cooling rate to a third predetermined temperature, which may be equal to or different from the first predetermined temperature; The sample is held at this third predetermined temperature for a second predetermined time, e.g., a predetermined number of minutes. It can be configured as follows.

[0125] Such cycles can be repeated any number of times, although a minimum of two cycles is recommended.

[0126] The analog measurement signal can be converted into a digital signal and subsequently into a temperature value. Various calculations and analyses can then be performed. For example, the change in temperature difference between the sample and reference chambers per unit time can be constructed to find characteristic phase transitions.

[0127] The disclosure is not limited to the above described embodiments, which can be varied in many ways within the scope of the claims. For example, multiple samples can be investigated in comparison to a single reference material, either in parallel or sequentially. The determination can be based on simultaneous or non-simultaneous measurements. Additionally or alternatively, samples can be investigated in comparison to several reference materials, for example when different reference materials are preferred for different (possibly overlapping) temperature ranges. Control of the gas composition can include changing from an inert gas to a mixture of reactive gases, e.g. oxygen-containing gases, to investigate the effect of one or more chemical reactions, e.g. oxidation.

[0128] Various embodiments may be implemented as a program product for use with a computer system, one or more programs of the program product defining the functionality of the embodiments (including the methods described herein). In one embodiment, the one or more programs may be stored in various non-transitory computer-readable storage media, where the expression "non-transitory computer-readable storage media" as used herein includes all computer-readable media with the sole exception of transitory propagating signals. In another embodiment, the one or more programs may be stored in various transitory computer-readable storage media. Exemplary computer-readable storage media include, but are not limited to, (i) non-writeable storage media in which information is permanently stored (e.g., a read-only memory device inside a computer, such as a CD-ROM disk readable by a CD-ROM drive, a ROM chip, or any type of solid-state non-volatile semiconductor memory), and (ii) writable storage media in which information that can be modified is stored (e.g., a flash memory, a floppy disk in a diskette drive, or a hard disk drive, or any type of solid-state random access semiconductor memory).

[0129] In particular, the device comprises: a sample container for holding a sample; a reference material and / or a reference material container for holding the reference material; a sample heater and a reference heater; a sample temperature detector for determining the temperature and / or temperature change of the sample; a reference temperature detector for determining the temperature and / or temperature change of the reference; Of any of the methods provided herein, heating and / or cooling the sample and the reference material; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change; determining at least one thermodynamic property of the sample and / or a composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; and means adapted to carry out There may be provided the above apparatus comprising:

[0130] Further provided is a computer program comprising instructions to cause the above mentioned apparatus to carry out the steps of any of the methods provided herein.

[0131] Also provided is a computer readable medium having stored thereon the computer program referred to above.

[0132] Elements and aspects discussed with or in connection with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless expressly stated otherwise.

Claims

1. 1. A method of differential scanning calorimetry comprising: Heating and / or cooling the sample and reference material; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change; determining at least one thermodynamic property of the sample and / or a composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; The process includes the steps of: wherein the sample is heated and / or cooled at a first sample side and the temperature and / or the temperature change of the sample is determined at a second sample side opposite the first sample side, and the reference material is heated and / or cooled at a first reference side and the temperature and / or the temperature change of the reference material is determined at a second reference side opposite the first reference side. The method.

2. Determining at least one of a temperature and a temperature change of the sample at the first sample surface; and / or determining at least one of a temperature and a temperature change of the reference material at the first reference material surface; The method of claim 1 , comprising:

3. 1. A method of differential scanning calorimetry comprising: Heating and / or cooling the sample and reference material; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change; determining at least one thermodynamic property of the sample and / or a composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; The process includes the steps of: wherein the sample is heated and / or cooled at a first sample side and the reference is heated and / or cooled at a first reference side, the method further comprising, where applicable, determining at least one of a temperature and a temperature change of the sample at a plurality of positions of the first sample side and / or the second sample side, and / or, where applicable, determining at least one of a temperature and a temperature change of the reference at a plurality of positions of the first reference side and / or the second reference side. The method.

4. 4. The method of claim 1 or 3, wherein the sample has a size in a first dimension that is at least an order of magnitude smaller than in a second dimension, and possibly at least an order of magnitude smaller than in a third dimension.

5. at least a portion of the sample is contained in an upright sample vessel, which may be liquid-tight to hold a liquid sample portion, and the first sample surface and the second sample surface are defined by horizontally opposite sides of the sample vessel; and / or at least a portion of the reference material is contained in an upright reference material container, the reference material container may be liquid-tight to hold a liquid reference material portion, and the first reference material surface and the second reference material surface are defined by horizontally opposite sides of the reference material container. The method according to claim 1 or 3.

6. The following formula [0010] 4. The method of claim 1 or 3, further comprising determining at least one thermodynamic property of the sample based on:

7. An apparatus comprising: a sample container for holding a sample; a reference material and / or a reference material container for holding the reference material; a sample heater and a reference heater; a sample temperature detector for determining the temperature and / or temperature change of the sample; a reference temperature detector for determining the temperature and / or temperature change of the reference; The method according to claim 1 or 3, heating and / or cooling the sample and the reference material; During the heating and / or cooling, determining at least one of the temperature and the temperature change of the sample and the reference material; controlling heating and / or cooling power to the sample and controlling heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change; determining at least one thermodynamic property of the sample and / or a composition of the sample based on at least one of the temperature of the sample, the temperature change of the sample, and the heating and / or cooling power to the sample relative to at least one of the temperature of the reference material, the temperature change of the reference material, and the heating and / or cooling power to the reference material; and means adapted to carry out The device comprising:

8. A computer program comprising instructions for causing an apparatus according to claim 7 to carry out the steps of the method according to claim 1 or 3.

9. A computer readable medium having stored thereon the computer program of claim 8.

10. 1. An apparatus for power compensated differential scanning calorimetry comprising: a sample container for holding a sample; a reference material and / or a reference material container for holding the reference material; a sample heater and a reference heater; a sample temperature detector for determining the temperature and / or temperature change of the sample; a reference temperature detector for determining the temperature and / or temperature change of the reference; a controller configured to control heating and / or cooling power to the sample and to control heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change relative to a predetermined temperature and / or temperature change; It is equipped with wherein the sample heater is configured to heat and / or cool the sample at a first sample side and the sample temperature detector is configured to determine the temperature and / or the temperature change of the sample at a second sample side opposite the first sample side; the reference heater is configured to heat and / or cool the reference at a first reference side, and the reference temperature detector is configured to determine the temperature and / or the temperature change of the reference at a second reference side opposite the first reference side. The apparatus.

11. a further sample temperature detector arranged in the first sample plane for determining the temperature and / or temperature changes of the sample; and / or a further reference temperature detector arranged on the first reference surface for determining the temperature and / or temperature changes of the reference material; The apparatus of claim 10, comprising:

12. 1. An apparatus for power compensated differential scanning calorimetry comprising: a sample container for holding a sample; a reference material and / or a reference material container for holding the reference material; a sample heater and a reference heater; a sample temperature detector for determining the temperature and / or temperature change of the sample; a reference temperature detector for determining the temperature and / or temperature change of the reference; a controller configured to control heating and / or cooling power to the sample and to control heating and / or cooling power to the reference material based on a difference in the temperature and / or the temperature change between the sample and the reference material; Equipped with wherein at least one of the sample temperature detector, if present, the further sample temperature detector, the reference temperature detector, and if present, the further reference temperature detector are configured to determine temperature and / or temperature difference as a function of position and / or comprise a plurality of temperature sensors at a plurality of positions on each of one or more of the first sample surface, the second sample surface, the first reference surface, and the second reference surface. The apparatus.

13. 13. The apparatus of claim 10 or 12, wherein the first and second surfaces of the sample vessel are opposite each other in a first dimension, and the sample vessel has a size in the first dimension that is at least an order of magnitude smaller than in the second dimension, and possibly at least an order of magnitude smaller than in a third dimension.

14. the sample container and / or the reference container comprise an upright sample container, the first and second surfaces being defined as upright surfaces on generally horizontally opposite sides of the sample container; and / or the sample vessel is liquid-tight to retain a liquid sample portion, e.g., a liquefiable fraction of the sample; 13. Apparatus according to claim 10 or 12.

15. 13. An apparatus as claimed in claim 10 or 12, comprising a sample chamber housing the sample vessel, and a gas and / or vacuum system connected to the chamber for controlling at least one of gas composition and / or gas humidity, gas temperature, gas flow around and / or through at least a part of the sample vessel.

Images