High pressure differential scanning calorimetry allows you to measure samples under precisely defined atmospheres at pressures of up to 10 MPa as a function of temperature or time. Higher pressures and temperatures accelerate chemical reactions and shorten analysis times. Increased pressure suppresses vaporization and shifts the effect to higher temperatures. The high-pressure DSC is an excellent instrument for studying the influence of pressure and atmosphere on a sample or for separating an effect that is overlapped by vaporization.
Increased pressure is a factor that influences all physical changes and chemical reactions in which a change in volume occurs. For material testing, process development or quality control there is often no alternative to DSC measurements under pressure. Measurements performed under pressure expand the scope of thermal analysis.
In the HP DSC 2 +, the low-inertia, fast heating/cooling DSC furnace is incorporated in a water-cooled pressure vessel. The furnace is specially insulated so that no temperature gradients occur. This guarantees a stable and reproducible baseline, even at higher pressures. A double safety system limits the pressure to the permissible range (bursting disk and construction of the sealing system). There are three gas connections each with a control valve for: - rapid filling (pressure build-up) - purging the furnace chamber during the measurement (flow control) - the gas outlet (pressure control).
The high-pressure DSC cell is based on the successful Thermal Analysis Excellence DSC technology and guarantees outstanding performance thanks to its FRS 6 + and HSS 9 + DSC sensors. The HP DSC 2 + operates at overpressures from 0 to 10 MPa and from room temperature up to 700 °C. A pressure gauge displays the actual pressure in the cell. An external pressure and flow controller is available as an option. This allows accurate pressure control in static and dynamically programmed atmospheres.
High pressure differential scanning calorimetry allows you to measure samples under precisely defined atmospheres at pressures of up to 10 MPa as a function of temperature or time. Higher pressures and temperatures accelerate chemical reactions and shorten analysis times.
Measurements under process conditions
Increased pressure is a factor that influences all physical changes and chemical reactions in which a change in volume occurs. For material testing, process development or quality control there is often no alternative to DSC measurements under pressure.
Increased pressure suppresses vaporization and shifts the effect to higher temperatures. The high pressure differential scanning calorimetry (HPDSC) is an excellent instrument for studying the influence of pressure and atmosphere on a sample or for separating an effect that is overlapped by vaporization.
DMA measurements can be performed under very different conditions to characterize the mechanical properties of materials. A great deal of information about a sample is obtained when the temperature, frequency or displacement amplitude is varied. The mechanical properties of composites or anisotropic materials can only be fully described by varying the direction of the deformation measurement or by using other measurement modes. This article discusses a number of typical examples.
The glass transition of semicrystalline polymers is often weak and difficult to measure by DSC. In this article, we show how a glass transition step of less than 0.1 J/g·K can be reproducibly determined using the DSC. The sample investigated was isotactic polypropylene (iPP) with a degree of crystallinity of 50%.
The TGA-GC/MS system can be used to investigate the composition of unknown samples. This is done by installing the IST16 storage interface between the TGA and the GC/MS. The interface allows up to 16 evolved gas samples to be stored at different furnace temperatures during the TGA measurement. The gas samples are analyzed and identified by GC/MS when the TGA analysis is finished. This article describes how a black polymer granule was characterized using this technique.
The mechanical properties of polymer-metal adhesive joints were studied as a function of the thickness of the adhesive layer using DMA. The glass transition temperature and the effective crosslinking density were evaluated from the shear modulus measurement curves. The results show that both quantities are strongly dependent on the thickness of the polymer layer. This is due to the formation of an interphase in the contact region of polymer and metal. The properties of the interphase depend on the metal used.
DMA measurements provide many different possibilities for characterizing materials. This article shows how DMA in combination with other thermal analysis techniques can be used to comprehensively characterize materials using different polymers as examples.measurement modes. This article discusses a number of typical examples.
Safety is an important aspect in process development in the chemical industry. This article, describes how reaction calorimetry and DSC can be used to quickly assess the thermal hazard potential of chemicals and chemical reactions.
In many applications, such as in cables or seals, rubber blends must possess both excellent mechanical properties and good flame-resistant properties. This article shows how flame resistance can be easily determined by TGA measurements and how the combination of mechanical and thermogravimetric measurements can be employed to optimize properties.
Photopolymerization is nowadays a widely used process. Systems are used for medical applications, for example in dentistry, for adhesive applications, in coating technology, and quite recently for 3D printing . This article describes how the curing behavior of a two-component UV-curing sample can be investigated.
Many different sorts of lipstick and mascara are nowadays available. The most important characteristics of these products are that the effect lasts a long time, that the products are easy to apply and easy to remove, and that they are physically and chemically stable and do not irritate the skin. The waxes and oils in lipstick are responsible for ease of application; carbon black is often used as pigment in mascara. Thermal analysis techniques allow the quality of these types of cosmetic products to be easily checked.
Tricalcium phosphate (TCP) is one of the main constituents of bone replacement materials which find wide use in medical and dental applications for bone grafting and for implants. This article shows how TGA/DSC and TMA can be used to investigate the synthesis of tricalcium phosphate and to determine the transition temperatures of different TCP polymorphs.
When polymeric binders are used in paints with hydrophilic pigments such as titanium oxide, the pigments must be treated beforehand with polymers that are compatible with the binder. Otherwise, large agglomerates can form due to poor adhesion between the binder and the particles. This can lead to brittle films and fractures in the paint coating. This article shows how TGA and DSC can be used to determine important properties of the coating using titanium dioxide as an example.
For many practical applications, it is important to be able to quickly and reliably identify polymers. This article describes how semicrystalline polymers can be identified by measuring their melting points using DSC.
A thermobalance coupled to a suitable Evolved Gas Analysis (EGA) system allows qualitative information to be obtained about the gaseous reaction or decomposition products formed in a TGA experiment in addition to purely quantitative information about mass changes. This new series of articles discusses the various measurement techniques that METTLER TOLEDO offers for such analyses.
The fluid bath DMA 1 option allows the influence of swelling on the dynamic mechanical properties of a sample to be measured in the temperature range 0 to 200 °C. This means that deformation conditions of components that are in direct contact with fluids can be simulated (for example drive or timing belts that permanently run in motor oil).
Crystalline pharmaceutical substances often decompose immediately before or during melting. To determine the glass transition temperature, the substance must be melted and then cooled as rapidly as possible so that decomposition and crystallization do not occur. In many cases, the heating and cooling rates of conventional DSCs are not high enough for this purpose. The METTLER TOLEDO Flash DSC however offers new possibilities. This is illustrated in this article using prednisolone as an example.
The interpretation and quantitative evaluation of thermal analysis measurement curves is difficult when several effects take place simultaneously. A number of methods are available that can be used to separate overlapping effects and analyze them individually afterward. Using suitable examples, we discuss strategies for DSC curves. A second article to be published in the next UserCom will cover TGA applications.
The shelf life of a packaged product, for example in the food sector, is often strongly influenced by the properties of the product packaging. An important factor here is the permeability of the product packaging toward water vapor. The ProUmid SPS and Vsorp sorption test systems in combination with special sample holders allow the transmission rate of water vapor through the packaging and the sorption rate of the packaged products to be determined experimentally.
TGA experiments in combination with a suitable evolved gas analysis (EGA) technique not only provide quantitative information about the change in mass of a sample but also qualitative information about the gaseous reaction or decomposition products that are evolved. In this series of articles, we will discuss the possibilities that METTLER TOLEDO offer.
DSC measurements can be performed up to about 700 °C using conventional DSC instruments. If higher temperatures are required, DSC curves can be measured up to 1600 °C using the TGA/DSC. This article compares DSC and TGA/DSC measurements and discusses how quantitative calorimetric measurements are possible in the high temperature region.
The first measurements of the thermal conductivity of powders  showed that powders can be an interesting alternative to vacuum systems for achieving good thermal insulation. Currently powders of different materials (ceramics or polymers) are used in packaging or for building insulation. On the other hand, the low thermal conductivity of powders entails serious risks in the production and manipulation of energetic powders intended for pyrotechnics or explosives. Knowledge of the thermal conductivity of powders is therefore crucial to avoid spontaneous ignition.
High demands are nowadays put on packaging materials. For example, depending on the application field, the materials must provide optimum barrier properties toward water vapor, oxygen or odorants. In addition, there are requirements regarding tear resistance, transparency and compatibility with the contents of the packaging. In this article, we show how the water vapor transmission rate of materials can be determined using a sorption test system.
The interpretation and evaluation of thermal analysis measurement curves is difficult when several effects take place simultaneously. A number of methods are available that can be used to separate overlapping effects and analyze them individually afterward. In this article, we discuss strategies for TGA curves using suitable examples.
Knowledge of the polymorphic forms of an active substance is very important, especially in the pharmaceutical industry. In this article, we show how previously unknown polymorphs of menthol can be identified and characterized by Flash DSC.
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