Mettler-Toledo International Inc. (MTD) Earnings Call Transcript & Summary

Ladies and gentlemen, welcome to this live webinar on characterization of thermoset by thermal analysis. My name is Thomas Oberholzer. I'm Product Manager for material characterization and thermal analysis and organizer of this webinar. Today's expert is Dr. Markus Schubnell from the market support group. Markus and I, we are both located at the headquarter of Mettler-Toledo in Greifensee, Switzerland. Let me briefly introduce Markus to you. Markus has worked for many years as a scientist in the field of renewable energy at Paul Scherrer Institute in Switzerland. Paul Scherrer Institute is one of the largest research institutes for natural and engineering sciences in our country. After this time, he moved to Mettler-Toledo to become a market support specialist. In this role, he has now collected more than 20 years of experience. And Markus is also the principal author of several publications in international journals and scientific journals, and he has also composed some of our larger handbooks on thermal analysis, of course. Markus will be happy to answer your questions during or after the presentation, and we hope you take the opportunity to discuss your terminal analysis or studies of thermal material questions with our expert. The main part of the webinar will be a prerecorded presentation and prerecorded part will last for about 45 minutes. So as you made experience that our content -- webinar content is quite compact, we will interrupt the presentation twice and our expert will give you some additional information and summarize some of the content. And of course, we hope you take the opportunity and ask questions, write down questions in the chat so that our expert can answer them. Of course, our expert will then answer via Team So thank you. And let's now start the presentation. Enjoy it.

Ladies and gentlemen, welcome to the Mettler-Toledo webinar on the thermal analysis of thermosets. Thermosets are polymers that can undergo a permanent chemical reaction known as curing to form a giant cross-linked network structure. They're also known as thermosetting polymers, resins or plastics. Fully cured thermosets are rigid, typically insoluble solid materials of high mechanical strength and high temperature stability. In contrast to thermal plastics, thermosets cannot be melted and remolded to other shapes after curing. Thermal analysis is an excellent method for identifying and characterizing thermosetting materials and end products because their properties are strongly temperature-dependent. The thermal analysis of thermoplastics and elastomers will be discussed in separate webinars. This slide lists the main topics that will be covered in this webinar. First, I want to discuss the most important thermal properties of thermosets and describe the thermal analysis techniques that can be used to measure them. The techniques include differential scanning calorimetry or DSC, thermal mechanical analysis or TMA, dynamic mechanical analysis or DMA and thermogravimetric analysis or TGA. I will then present a number of examples that illustrate how thermal analysis can be used to investigate the physical properties and behavior of thermosetting materials. Finally, I will summarize the different thermal analysis techniques and their application fields and list a number of useful references for further information and reading. The term thermosetting resin was originally used to describe liquid resins become solid and hard on heating in contrast to thermoplastics, which become soft and melt on heating. Nowadays, the word thermoset is used generally for systems that irreversibly harden irrespective of whether this is achieved through the action of heat, exposure to UV light or the addition of reactive components. In all these cases, an irreversible chemical curing reaction takes place. The measurement curves on the right part of the slide illustrate the different thermal analysis techniques that can be used to measure and characterize thermosets. In this case, the thermoset was an epoxy resin powder known as KU600. Thermal analysis can be used to determine many of the key properties of thermosets. For example, an important application is the measurement of the glass transition and the curing reaction in epoxy resin systems. The figure displays the DSC curing curve of a fresh resin, the post-curing curve of a partially cure resin and the curve of the fully cured thermoset. The results show that as the degree of cure increases, the glass transition shifts to higher temperatures and the post-curing reaction enthalpy decreases. If the reaction enthalpy of the uncured resin is known, the degree of conversion can be calculated from the enthalpy of the post-curing reaction. In general, thermosets are amorphous, that is they do not melt but merely soften at the glass transition. This defines the upper temperature limit for their practical use. The schematic diagram illustrates the curing reaction. This is a complex polymerization process involving different reaction steps. Thermosets are often identified at 3 stages of cure, A, B and C. The A stage refers to unreacted mixtures of small reactive molecules, often monomers with 2 or more functional groups, one. The reaction proceeds through linear growth and the branching of chains to partially reacted increasingly viscous and usually vitrified B stage material below the gel point, two. On further heating, this devitrifies, undergoes further reaction and cross-linking, three. And can be processed to the completely cured C stage thermoset, four. Thermal analysis techniques can be used to obtain information about the reaction process, such as the gel point where the viscosity increases markedly the pot life or processing time and the shelf life, which is related to the practical storage time of the thermosetting system. The ICTAC definition of thermal analysis is a group of techniques in which a physical property of a substance is measured as a function of temperature, whilst the substance is subjected to a controlled temperature program. The schematic diagram on the right shows a simple linear temperature program. The lower half of the slide illustrates the main events that occur when a sample is heated. These include initial melting in which the sample changes from the solid to the liquid state, followed by oxidation if the sample is exposed to air or oxygen, and finally, decomposition. Thermal analysis techniques can be used to measure properties such as the heat capacity, thermal expansion, mechanical modulus, softening, the change in sample mass and chemical stability, to name just a few. The slide shows the 4 most important thermal analysis techniques that are employed to characterize thermosets. DSC allows you to determine the energy absorbed or released by a sample as it is heated, cooled or held at constant temperature. The picture shows a DSC sensor with a crucible containing a sample and a reference crucible. TMA measures dimensional changes or the changes of mechanical behavior of a sample as a function of temperature. The picture shows the sample area with a quartz probe resting on the sample. DMA measures the mechanical properties of a material as a function of time, temperature and frequency while it is subjected to a periodic stress. The picture shows one of the several different sample clamping assemblies. Finally, TGA measures the mass of a sample as a function of temperature in a defined atmosphere. The picture shows the unique Mettler-Toledo Ultra microbalance with its automatic internal ring weights. The table summarizes the extremely wide applications field of thermosets. They are used in practically all industries ranging from automotive to medical. One of the primary uses of thermosetting resins is as a matrix material in composites. Today, composites are widely used as high-performance engineering materials in the automotive, aerospace, boat building and other industries. Adhesives are another major application area. A large volume is also used in the coating industry and electronic components for wind power systems and for sports goods. Thermal analysis techniques are employed to measure thermal stability, determine glass transitions for investigating the degree of cure to optimize processes and for studying the mechanical behavior of materials. Because the techniques are widely used in quality control, many of these analyses are defined in international standard methods. Let us begin with DSC. This technique allows us to measure the amount of heat absorbed or released by a sample. The standard Mettler-Toledo DSC1 instrument operates from minus 150 degrees Celsius to plus 700 degrees at heating rates of up to 300 kelvin per minute. Samples are normally measured in small crucibles made of aluminum, alumina or other materials using sample amounts of 2 to 20 milligrams. The schematic curve on the left shows a typical DSC measurement curve of a semi-crystalline polymer. Exothermic effects point in the upward direction and endothermic effects downward. The effects are numbered next to the curve and explained in the table. These are: one, the initial deflection or start-up transient of the DSC; two, the evaporation of moisture; three, a glass transition of the amorphous fraction with enthalpy relaxation; four, chemical reaction, curing; and finally, five, the beginning of oxidative exothermic decomposition. Special instruments allow you to measure samples at higher or lower gas pressures or at ultrafast heating and cooling rates. The main analytical applications of DSC for thermosets are summarized in the table, and have to do with the measurement of glass transitions, specific heat capacity curves, the enthalpy of reactions, reaction kinetics and thermal stability. This information can be used to identify polymers and define the working range of materials. Furthermore, it can be employed in quality control and analysis of raw materials and to study the influence of additives. The measurement of reactions such as the curing reaction is an important application. The picture on the right of the slide shows a view of an open DSC furnace with sample and reference crucibles. The first application demonstrates the relationship between the glass transition and the degree of cure. The experiments were performed using a 2-component epoxy resin system consisting of DGEBA and DDM. The diagram shows the DSC curing curve of a fresh sample and the post-curing curves of a series of samples that had been partially cured at 100 degrees Celsius for different times to obtain different degrees of cure. After curing, the samples were rapidly cooled to minus 40 degrees before measurement. The series of curves shows that with increasing curing time, the exothermic post-curing peak decreases and the glass transition temperature increases. The glass transition temperature does not, however, exceed 125 degrees because the sample vitrifies under these conditions. Only curing at a higher temperature leads to complete cross-linking and the maximum possible glass transition temperature of 155 degrees. To achieve this, the thermosetting material has to be heated to at least 170 degrees. The upper left inserted diagram shows the relationship between the degree of cure, alpha and the glass transition temperature, TG. This allows the degree of cure to be determined in a routine analysis from a measured value of TG. The glass transition is, therefore, an important criterion for assessing the quality of a product. The top green curve displays the post-curing curve of a laminated composite material with a very high glass transition temperature, recorded in a conventional DSC experiment. The post-curing reaction often begins at the glass transition when the mobility of the reactants increases. The effects due to the exothermic reaction and the change in heat capacity at the glass transition then overlap. This makes it difficult to determine the glass transition temperature and the post curing enthalpy in the conventional DSC measurement. This problem can be overcome by using a temperature modulated DSC method known as TOPEM. This separates the 2 effects into reversing and non-reversing heat flow components. The reversing heat flow curve shows the change in the specific heat capacity due to the glass transition, and the non-reversing heat flow, the enthalpy of the post-curing reaction. The sum of both heat flow components is the total heat flow. This application has to do with reaction kinetics or the rate of reaction. The goal of such experiments is to be able to model and predict curing behavior. The example shows how the reaction kinetics of a 2-component resin used for constructional reinforcement elements can be described by model free kinetics, MFK software. The first step is to measure at least 3 dynamic DSC curves at different heating rates, as shown in the upper left diagram. This data is then used to calculate conversion curves from which the activation energy of the reaction can be calculated as a function of conversion. This allows the degree of cure to be predicted as a function of time. For example, at 42 degrees Celsius as shown in the lower half of the diagram. To check the kinetic prediction, samples were first cured for different periods at 42 degrees. DSC post-curing measurements were then performed to determine the reaction conversions that had been attained. The results are shown by the blue stars and agree well with the predicted reaction curve. The post-curing curve showed that the resin system was still not completely cured even after more than 36 hours. This is due to the vitrification of the resin. The diagram shows DSC curves of a phenolic resin measured in different crucibles. The effects due to the endothermic vaporization of water produced in the polycondensation reaction of phenolic resins and the exothermic curing reaction often overlap. The curing peak is then no longer clearly defined and kinetic evaluation becomes impossible. The temperature range in which these 2 phenomena simultaneously occur is indicated by the arrow above the dashed curve. If the curing reaction is measured in a high-pressure crucible or in a high-pressure DSC instrument, the vaporization of the water is suppressed or shifted to higher temperatures. As a result, the effects due to curing and vaporization no longer overlap, and the exothermic reaction can be properly recorded. The reaction peak free from effects due to vaporization is indicated by red asterisks. The DSC photo calorimetry accessory allows you to characterize UV curing systems You can study photo-induced curing reactions and measure the influence of exposure time, light intensity and temperature on the rate of reaction and material properties. The upper right inserted diagram shows a schematic view of the measuring cell of the Mettler-Toledo DSC photo calorimetry system. Both the sample and the reference sides are exposed to the same light intensity. This is done using a branched fiber optic light guide. One end is connected to a suitable light source. The 2 exits are fixed in a holder and positioned directly above the sample and reference crucibles of the DSC. The holder can be mounted and demounted in about 2 minutes. This means that the DSC can be used for both photo calorimetric and normal DSC measurements. In this experiment, the sample was held constant at 130 degrees Celsius. After 6 minutes, the shutter of the light source was opened, and the sample exposed to UV light for 15 minutes. The reaction shown by Curve 1 begins as soon as the light irradiates the sample and dies down after a certain time because the possible reactants have been used up. That is undergone conversion. If the fully converted sample is exposed to light again in the same way as before, no further reaction peak is observed. Curve 2 can therefore be used as a blank. The blank subtraction takes into account that a small amount of the absorbed light is converted to heat. This is the cause of the small step in the DSC curve at the beginning and the end of the measurement under UV light in curves 1 and 2. The difference between the curves yields the net heat power of the cross-linking reaction. The optimum conditions for a sample to achieve an adequate degree of cross-linking can then be determined by systematically varying the exposure parameters.

Good afternoon, ladies and gentlemen. This is your expert speaking. I realize that there are no questions so far. So if you have any questions, please put it into the chat. In the meantime, maybe I can explain a little bit -- or give you some more details regarding the photo calorimetric and talk a little bit about different type of light sources. So it was mentioned that we have a lamp, and this lamp will be basically -- they will be opened shorter and then the light will be actually arrived at the sample side and then at the reference side. In fact, we have not just one single lamp, we have different type of lamps. So we have one lamp, which has an enhanced UV contribution, and we have another lamp, which is more like a visible -- which is more in the visible range, wavelength range, yes. And in this case here, we have these 2 branches, which come from the light source and one branch will be on top or above the sample side and the other one will be above the reference side. Now we have also a different type of light sources. So these lamps, it was 10 years ago or 15 years ago. Nowadays, we have something like LEDs. And the difference between an LED and the light bulb and a light source like a lamp is that the lamp has always a spectrum, whereas an LED has just a particular wavelength. So for an LED system, typically, there are different heads, and these heads will offer different type of wavelengths. So typically, we have the 365-nanometer that corresponds to the mercury line, the strongest mercury line in the spectrum of mercury. Then you have something like 385 and also 400 nanometers in most of the -- in many systems. That is also true for the one system which we are offering, which is this OmniCure system. And it's not exactly true if we offer or if we talk about the DELO system, which is the one which you see on the right side in the diagram. So the DELO system goes to a higher -- to large -- to longer wavelengths, up to 460, starting at 365 and 400 nanometers somewhere in between. Now the difference between these 2 LED systems is indicated a little bit in what you have on the top. There you see that the OmniCure system basically has one side, which is illuminated. So that will be the sample. And the reference cannot be eliminated because simply by geometrical reasons, whereas in the system, we have a broadband, so to say, or a wide irradiation spot, which allows you to, again, basically irradiate the sample as well as reference side. This has the advantage that you bounce off a little bit of a background. So the system is more or less symmetrically loaded and net you should get just what is absorbed by the sample. So this is one difference between these two systems. Another difference is that the DELO system has as a head, an LED head which is cooled, which has the advantage that due to if the LED is on, basically, this head will start to heat up. If it heats up, the efficiency will be less, and the intensity will not be stable. And therefore, this head is cooled. Now in case of DSC, photo calorimetry, basically that is not an issue because we usually apply just a very short or a rather short time of exposure. That means that the light -- when the light is on that is quite for short time, and that means that the head is not really getting hot and needs not to be cooled consequently, and they will not drift away because of thermal effect. So these are maybe just 2 differences or the differences between these 2 LED heads, which we also offer. Yes. Now maybe a little bit -- I was talking about the spectrum of the lamp. And here you see on the upper left, you see such a lamp characteristics that will be for different light sources. There are other light source types which are available. And you see we have clearly these large peaks, they correspond to these kind of spectra. The one which is for 365 that corresponds basically mercury spectrum. And this has the largest peak at 365 nanometers. That's why this is very convenient. So if you now are looking into an LED, for instance, the LED which emits 365. You have to imagine that you only get this peak, which is at 365 in the spectrum of the ramp and the peak will be even more narrow than what you see from the lamp. So it is really something which is a mono wavelength if you like. So you irradiate your sample, it's just one typical wavelength. So that is one thing which is also a difference between the lamp and between the LED system. Now the LED is very sensitive for the which arrives at the sample side is very much depending on the distance of where you place your LED in the system, and that is illustrated on the other 2 diagrams which are on the right-hand side. So the upper diagram shows you the characteristics of what is the OmniCure system. And you see that if you want to get a very high intensity, that will reduce basically the spot where you will get the high intensity. In our case, we prefer to have something which is like a uniform irradiation. That means we are -- we are talking about the which has something like 4, 5-millimeter in diameter or 4-millimeter diameter, which means that we are somewhere on the lower grade curve, which means that we get peak intensities of around 600 millivolts per square centimeters. This is already quite a lot. So most of the time people are not using such high values. Most of the time, people are using more like 100, 200 millivolt per square centimeter. If you compare this characteristic with what the DELO system is offering, that is the curve below, you then see that here the spot is much larger. So we are talking about radius of 10 millimeters in this order of magnitude, which is clearly more than what we have in case of the OmniCure system. So these are some differences between these different type of lamps and the spectra and so these are some information on photocalorimetry in general. Okay. So I realize there are no questions so far. So I propose that we continue with the presentation.

Let us now move on to thermomechanical analysis or TMA. This is a straightforward technique to measure mechanical properties of materials by measuring the dimensional changes of the sample as it is heated or cooled under a defined load. The schematic curve shows the typical TMA measurement curve of a polymer under a small load. The different effects are numbered next to the curve and explained in the table. These are: one, expansion below the glass transition; two, the glass transition point indicated by a marked change in the rate of expansion; three, expansion above the glass transition -- the steeper slope indicates a greater rate of expansion; four, delamination; five, plastic deformation. The table lists the most important applications of TMA for thermosets such as the measurement of the expansion behavior, contraction or softening phenomena, glass transition, gelation and swelling of material in a solvent. The picture shows the sample mounted on a quartz support. The thickness is continuously measured by the TMA probe resting on the sample and yields the sample expansion as a function of temperature. In this experiment, the glass transition temperature, the coefficient of thermal expansion, CTE and the delamination temperature of a printed circuit board, PCB, were determined in one single TMA measurement. The PCB sample consisted of glass fiber with an epoxy matrix resin and flame retardant. The change in the slope of the TMA curve at about 93 degrees Celsius is due to the glass transition. As we can see, the CTE curve exhibits a large step in this region. The first irreversible change in the expansion curve at 323 degrees Celsius indicates the beginning of delamination under the measurement conditions used. This application shows how the viscosity of an adhesive increases with increasing conversion during isothermal curing. The material was initially in the liquid state, but then reacted to form a solid. The gel point is of major interest from the technical point of view. This is the point at which the adhesive becomes structurally stable. Gelation can be investigated by periodically raising and lowering the TMA probe out of and into the sample in an up and down movement. The probe is able to move freely until the resin gels and becomes rubbery like. On further reaction, the sample hardens and the amplitude changes to a very small value. The reaction time at which the probe can no longer be lifted out of the sample is the gel point. In the measurement shown, this is clear from the sharp decrease of the envelope difference curve after a reaction time of about 26 minutes. In the dynamic load TMA or for short DLTMA mode, the force exerted on the sample alternates between a higher and a lower value at a fixed frequency. DLTMA can be used to follow the cross-linking of a sample during curing. The method reacts very sensitively to changes in the elasticity of a sample and is therefore a good technique in quality control and damage analysis. In this example, the 3-point bending accessory was used for investigating a composite material. The ballpoint probe touching the center of the sample exerted an oscillatory load that varied from 0.02 to 0.5 Newtons over a period of 12 seconds. The heating rate was 10 Kelvin per minute. The TMA software calculates the mean curve as well as the value of the Young's modulus from the blank corrected DLTMA curve. Glass transitions of highly filled polymers can be easily detected using 3-point bending due to the large change in modulus. Dynamic mechanical analysis or DMA measures the mechanical properties of viscoelastic materials as a function of time, temperature and frequency when the material is deformed under a periodic oscillating stress. The sample response is analyzed over a wide frequency range of up to 1,000 hertz. The modulus consists of 2 components: the storage modulus, M prime and the loss modulus, M double prime. The storage modulus corresponds to the elastic behavior, the solid line of the material, whereas the loss modulus, the dashed line is related to the viscous behavior of the material. Another useful quantity is tan delta, also known as the loss factor or dampening factor. Tan delta is the ratio of the loss modulus and the storage modulus and as a measure of the amount of energy dissipated as heat during each deformation cycle. The schematic diagram shows the results of a DMA measurement of a reactive resin. The curves display M prime and double prime as a function of temperature. The different effects are numbered next to the curve and explained in the table. These are: one, the glassy state; two, the glass transition seen as a decrease in the storage modulus; three, viscus liquid; four, cross-linking; five, gel point; six, rubbery state. Several different clamping modes are available for DMA measurements, for example, for shear, tension and bending experiments. The mode used depends on the information required and the behavior and geometry of the sample. The table lists the main analytical applications of DMA for thermosets. In general, DMA provides information about the mechanical modulus, compliances, damping properties and viscoelastic behavior as a function of frequency. The glass transition temperature is detected through changes in the modulus or as peaks in tan delta. The most important DMA applications have to do with the determination of the glass transition and mechanical modulus of composites and the determination of gel time. The picture on the right shows a sample installed in a DMA clamping accessory ready for measurement in the bending mode. The first DMA application displays the storage modulus and tan delta curves of a cured epoxy resin powder in the shear mode as a function of frequency and temperature. The storage modulus curves labeled G prime show a step change in the glass transition region, whereas the tan delta curves display peaks. It can be seen that the peaks are shifting to higher temperatures at higher frequencies. The glass transition is a relaxation effect. It has its origins in the molecular mobility of cooperative units. With increasing temperature, the frequency of the cooperative rearrangements increases. At low temperatures, the frequency of these rearrangements is much lower than the measurement frequencies used. In this case, the sample appears hard, and the storage modulus is therefore large. At higher temperatures, the frequency of the cooperative rearrangement is much higher than the measurement frequency. The material then appears soft and has a low storage modulus. The second DMA application shows the curves obtained from the measurement of a 2-component epoxy resin system in the shear mode. During curing the modulus changes by more than 6 orders of magnitude. In the shear mode, the glass transition of the fresh and the cured resin as well as the gel point can be measured in one single experiment. In the upper diagram, the glass transition of the uncured resin is shown by a marked decrease in the storage modulus, G prime at about minus 10 degrees Celsius. In the liquid phase G prime is very low and cannot be measured. The loss modulus, G double Prime starts to increase at about 120 degrees due to curing and the viscosity increases. The gel point corresponds to the temperature at which G prime equals G double prime. In this case, at about 150 degrees. The glass transition of the cured material can be determined in a cooling experiment. The viscosity curve of the liquid sample shown in the lower diagram was calculated from the loss modulus.

Okay. Yes, so far, so good. So that's the second intervention of your expert. I realize that there are still no questions. So I might eventually show you some details regarding the DMA technique. So basically, Mettler-Toledo is offering 2 type of DMAs. One is what we call the DMA/SDTA 1+. We call that also the large machine and we have a small machine, which is what is called the DMA 1. So both of these things are DMAs, but they are completely different in what they can do and in what their characteristic properties are. And then I would just mention a little bit what the difference is because some people think DMA is a DMA and it's all the same. It's not really true. So if we start with the heavy machine, the DMA/SDTA 1+, then one characteristic of this instrument is it has a very high stiffness. So the stiffness of the instrument is huge. And that is important if you want to measure stiff materials. And stiff materials, for instance, would be, if you have like a massive piece of a composite material, so something which is reinforced with, let's say, carbon fibers or glass fibers. And these things, they will be very stiff. And if you want to measure the response of the sample, you need also a very stiff instrument because otherwise you measure basically the instrument and not the sample. And that's why it is good to have like high stiffness instrument because that allows you to measure also highly stiff materials, samples. Now that is one thing, which is are characteristic, let's say, of this instrument. Then another thing is it's probably best in class if we consider all these DMAs which are on the market. If we are talking about shear experiments. And shear experiments, I think that is the mode in which you really can make like a huge number of Dk, so we are talking about Dk if you're talking about DMAs. So if you have a change of stiffness of, let's say, 8 Dks or 70 Dks, we have seen that just before, that is only possible to do the measurement in shear because figure out that you have something which is in bending and you have 7 Dks, it will actually flow away and you will be lost after, let's say, 4 or 5 Dks if you are lucky. So shear is the only mode which allows you to cover like 9 Dks change during an experiment. Another advantage or feature of this instrument is that we can actually use very large specimens. That means that they can be as long as 10 centimeters. The thickness can be like 5 or even more millimeters with also 5 or 8 millimeters in this order of magnitude, which means that you have really something which is representing your material. And that is particularly important if you are talking about composites. And this means that in this case, your materials will be quite stiff, and the large test specimen allows you to actually reduce also the stiffness, especially if you can take longer samples and just 5-centimeter-long samples. We have to imagine that the stiffness changes with the third power of the length of the sample. And finally, another point where I would actually use this DMA/SDTA 1+ would be if you are interested in time temperature applications. So if you are using this time temperatures superposition principle, you need a large frequency range, which you can apply to your sample. This DMA offers you like 4 Dks frequency for practical reasons, let's say, and that is important if you want to your time temperature superposition curve in an easy way or work with not too many measurements. That means also in some reasonable amount of time. So these are some details maybe to this large DMA. Then the small DMA, I mean if you are talking about the small DMA, people think it's a toy, but it's not a toy. It has just a different application range. And I think my personal view is that this DMA 1, that is the best instrument for tension. Tension not really very high stiffness machine, but it needs a very good control for low forces, and that is what this DMA 1 is actually offering. Then in addition, it is possible to measure with this DMA also samples, which are actually in the fluid path. So you can expose them to some oils or some water or whatever and then measure what is the impact of a solvent, for instance, that would be possibly some swelling. Swelling will also change the modulus. So these kind of processes you can follow if you are applying or if you are running or measuring your samples in some liquid. Another possibility with this instrument is that you can combine it with a humidity generator. And then you can expose your sample simultaneously to some humidity. And you can check what is the influence of humidity on the behavior -- on the mechanical behavior of your material. And finally, for me, quite important also is to strengthen a little bit that this DMA 1 is really easy to operate. I mean, here, you do not need a lot of experience to make an nice on the reasonable curve. Whereas with the DMA/SDTA it needs a little bit more expertise. You have to know what you want to do. And you have to understand in very much detail or in much detail a little bit also how this machine is working. Otherwise, you will actually run into troubles and eventually not produce very nice curves. If you understand the machine, then it's perfect, then you will produce wonderful numbers and wonderful experiments. But it is a little bit more demanding regarding the scale of the operator than it is with the DMA 1. So these are maybe some remarks regarding the 2 instruments which we offer. The message is these are both DMAs, but they are completely different in terms of what they can do, in terms of applications and also in terms of user friendliness, let's say. Okay. I realize there are still no questions. So I propose again to continue with the presentation.

The final technique I want to discuss is thermogravimetric analysis or TGA. In TGA, the mass of a sample is continuously measured as it is heated or cooled in the defined atmosphere. The schematic curve shows the typical TGA measurement curve of a polymer. The steps due to loss of mass provide valuable information about the composition of materials. The steps are numbered next to the curve and explained in the table. They are: one, heating begins and volatile components vaporize; two, pyrolysis of the polymer under inert conditions. At 600 degrees Celsius, the atmosphere is switched from nitrogen to oxygen to obtain oxidative conditions; three, carbon black or carbon fibers burn; four, a residue of inorganic substances remains. The large step indicated by step two is the main of the polymer. This step can be used to determine the amount of a particular component. The temperature at which the step occurs is characteristic for the type of polymer investigated. TGA is used to investigate processes such as vaporization or decomposition. Evolved gases, for example, from condensation reactions can be analyzed online using hyphenated techniques such as TGA-MS or TGA-FTIR. The table summarizes the main analytical applications of TGA for thermosetting materials. The technique provides information about the composition of samples, including their fiber or filler content. Furthermore, it allows us to check the thermal or oxidative stability of products or analyze the content of moisture or volatiles in products. The picture on the right side displays a view of the open furnace, a sample holder with 2 positions for the sample and reference crucibles in the TGA instrument. The standard crucibles are made of alumina. The first TGA application shows the measurement of an epoxy powder and illustrates how compositional analysis is performed. Approximately 15 milligrams of a sample was heated from room temperature to 600-degrees Celsius under nitrogen and then from 600 to 850 degrees under air. The TGA curve exhibits 2 steps. The first step between 320 and 480 degrees corresponds to decomposition of the polymer through pyrolysis. The step height is proportional to the polymer content and is normally expressed as a percentage. The carbon present burns on switching to air. The DTG curve is the first derivative of the TGA curve. In this case, it helps us to determine the optimum limits for the step evaluations. The two main steps are thus observed as large DTG peaks. Mettler-Toledo TGA instruments simultaneously measure the mass loss and the DSC heat flow signal of the same sample. The DSC curve provides additional information that can be used to identify thermal events. The combustion of carbon on switching to air produces a large exothermic effect, which is shown as a large DSC peak. In contrast, pyrolysis of the resin exhibits only a small endothermic effect. The TGA and DTG curves alone do not show the glass transition or the exothermic curing reaction. These thermal events are, however, observed in the DSC curve at about 70 and 200 degrees Celsius, respectively. The DSC signal clearly provides very useful complementary information. In this application, a hyphenated technique consisting of a mass spectrometer connected online to a TDA instrument was used to analyze volatile decomposition products from a printed circuit board. The mass spectrometer, MS allows volatile decomposition products evolved from the sample and the TGA to be qualitatively and quantitatively analyzed. Compounds with a sufficiently high vapor pressure passed from the TGA into the MS, where the fragment ions are analyzed according to their mass to charge ratio. The upper diagram shows the TGA and DTG curves. These exhibit, a large one-step mass loss of around 30%. The mass spectra of the evolved gases exhibit fragments with master charge ratios of isotopes that can be easily assigned to bromine. The curve in the lower diagram displays the ion current of bromine with a mass to charge ratio of 79. This ion current curve shows that decomposition products containing bromine are evolved in the decomposition step. The table lists the chief events and properties that characterize thermosetting materials and the thermal analysis techniques recommended for their analysis. A red box denotes the recommended technique, a blue box indicates that the technique can also be used as an alternative. The most important effect that can be analyzed by DSC are the glass transition, melting behavior, reaction enthalpy, curing and thermal stability. TMA is normally used to study the mechanical behavior of materials such as expansion, shrinkage, softening and the glass transition. DMA is the best method for characterizing the viscoelastic behavior of materials, the glass transition and the frequency dependence of effects. The main applications of TGA are compositional analysis, thermal stability and decomposition and evaporation and desorption behavior. Finally, I would like to draw your attention to information about the analysis of thermosets that you can download from the Internet. Mettler-Toledo publishes articles on thermal analysis and applications from different fields twice a year in UserCom, the well-known Mettler-Toledo biannual Technical Customer Magazine. Back issues can be downloaded from www.mt.com/ta-usercoms. A large collection of applications can be found in the Thermosets and the Thermal Analysis in Practice handbooks. In addition, information about webinars, application handbooks or of a more general nature can be downloaded from the Internet addresses given on this slide. This concludes my presentation on the thermal analysis of thermosets. Thank you very much for your interest and attention.

Okay. Last intervention of your expert. So you have now heard a lot about glass transitions. Maybe that's just a remark. So DSC can make it, TMA can make it, DMA can make it, and maybe you ask yourself, is it all the same or is it somehow different? Or what is the difference? Are they also equally sensitive? Or are they not equally sensitive? And the first thing to mention is they all measure -- all these techniques measure different properties. I mean, if we are talking about the DSC, we are basically measuring a change in the heat capacity. If we are talking about the DMA, we are talking about the change of the modulus. And if we're talking about TMA, we are talking about the change of expansion coefficient. So these are all 3 different properties and that tells you already that probably they will not be equally the same numbers if you calculate the glass transition from a DSC experiment and you want to compare that with what you do as a TMA experiment. And this, again, you want to compare with what is -- what is coming out from a DMA experiment. You will not get exactly the same numbers. That is one remark. Second remark is if you are talking about the DMA, we have an additional parameter. You are seeing that we have the frequency. And obviously, this plus transition, which you measured by DMA depends on frequency. And there's a rule of thumb, one can say that if you change a frequency by a factor of 10, you basically change the glass transition by about 5 degrees. So these are some findings regarding how the numbers can be compared. So basically, they cannot be compared. And that at the end of the day, you can say the reason is that there is no two-glass transition temperature -- because the glass transition temperature will depend on what you measure and also how you measure what you want to measure or what you measure. So this is maybe some general remarks. Another thing would be the sensitivity. And as a matter of fact, the DSC is not the most sensitive technique. But as if we are talking about the TMA that it will be more sensitive. And if you are talking about the DMA, then this will be the most sensitive technique because here, we can actually change. We measure changes of Dks if you are looking into the property work measure, which is the modulus. If you are talking about expansion coefficient, we have a factor of 3. And if we measure regarding the CP, the change will not be a lot. I mean we are talking about small changes, 0.3, something like that joules per gram per kelvin. If you normalize that to the initial kind of CP of the material that is maybe around 1. So we are talking about a 30% effect. So from that point of view, DSC is least sensitive, TMA somewhere in between, and DMA will be the most sensitive technique to measure glass transitions. Okay. I realize that there are no questions. So again, I think -- I thank you for your attendance. And maybe I can also advertise a little bit some upcoming webinars. So in April, end of April, the subject will be evolved gas analysis. So here, we will talk about the combination of TJ with analytical of evolved gas analysis such as MS, FTIR or GC/MS, these kind of things. Then one month later, we will present [ thermal analysis ] with food industry. So that will be dedicated to all kind of food stuff and also to packaging materials. And in June, the subject will be 21 CFR Part 11, so that will be probably more for people working in pharmaceutical and food industry, but it's also important maybe to know a little bit what are the regulations and what are the requirements regarding compliance and what can be done to fulfill these requirements. Okay. So that was it from my side. I thank you very much for participating, and I wish you a nice evening.

Now you have a question.

There's a question. Thank you. Yes, of course. I mean the question is can samples be mixed composite of different thermosets and additives in DSC and DMA mixed? Of course, you can measure whatever you want. The question is whether you understand what you actually get. So in many cases, you might get different type of feedback, which will be eventually overlapping and that may make it difficult to understand what is going on. But of course, you cannot just measure pure thermosets I mean that's -- some people may think that a thermoset is a pure material. If you are thinking more in composites, where a thermoset is one component basically the matrix for some filler for instance, then of course this is more interesting actually to be analyzed rather than just a pure thermoset. But of course, you can measure any mix -- any mixtures and composite materials with the sale technique, which I have been discussed now for pure thermosets if you like. I mean, the meaning of thermoset is basically something which is doing a curing reaction. And typically, one has pure resins. But of course, pure resins can be different in composition, you can mix things together. You can add you can fillers add colorants, you can have fire retardants or whatever. And all these things, of course, will impact also the behavior of the final product, and this can also be measured by these different techniques. Okay. So then there are no more questions. So I thank you very much for attendance and hope to see you one more time in another webinar.

Okay. Bye-bye to everybody.