Here, the thermal characteristics of various polymer materials were evaluated by using the tm dsc technique. Dsc and modulated di erential scanning calorimetry mdsc. Understanding glass through differential scanning calorimetry. The theory supporting modulated dsc can be easily understood by comparing it to conventional dsc. Introduction the conventional dsc method, we measure heat flow as well as temperature, such as glass transition, crystallization, or melting, by detecting differences in heat flow to a sample and reference material by heating or cooling at a constant rate. Therefore, larger amplitudes increase sensitivity for transitions such as the glass transition. Resolving glass transition in tebased phasechange materials by modulated differential scanning calorimetry to cite this article. Study of glass transition of metallic glasses by temperaturemodulated differential scanning calorimetry mdsc z.
Nov 03, 2009 temperature modulated dsc, abbreviated tm dsc, is an extension of the conventional dsc technique. The use of modulated differential scanning calorimetry mdsc as a novel means of characterising the glass transition of amorphous drugs has been investigated, using the protease inhibitor saquinavir as a model compound. An analytic solution for the frequency dependent fictive temperature is obtained, which takes a particularly. Dielectric and mechanical relaxation processes in the series of polynalkyl methacrylates pnama depend systematically on the number of carbons in the alkyl part of the side chain. Introduction measurement of the glass transition and glass transition temperature are probably. Senior applications scientist ta instruments waters llc thanks to college of textiles north carolina state university. Study of glass transition of metallic glasses by temperature. Characterization of the glass transition temperature of. Fengb adepartment of materials science, faculty of science, national university of singapore, blk s1a, lower kent ridge road, singapore 119260, singapore.
Differential scanning calorimetry dsc is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Figure \\pageindex32\ standard exo up heat flux dsc spectrum of the pet polymer. Determination of the glass transition temperature core. Request pdf the application of temperaturemodulated dsc to the glass transition region ii. Contrary to figures 2, which shows an endothermic peak at glass transition, figures 3 shows no such peak. Modulated temperature differential scanning calorimetry mtdsc is a thermoanalytical technique which involves the application of a sinusoidal heating or cooling signal to a sample in the case of the ta instruments model and the subsequent measurement of the reversing and nonreversing components of the heat flow response reading, 1983, reading et al. Kasap department of electrical engineering, university of saskatchewan, saskatoon, canada abstract temperature modulated differential scanning calorimetry tmdsc is a relatively new thermal analysis technique that incorporates not only the ability of.
Pdf relaxation dynamics of glass transition in pmma. To overcome these problems, temperature modulated dsc tmdsc can be utilized, in which a sinusoidal heating rate is superimposed on the linear heating rate known from standard linear dsc. The crossover region of the dynamic glass transition shifts to lower frequencies for increasing this c number and reaches, above the hexyl member c6, frequencies accessible to the temperature modulated dsc tmdsc. The reversible and nonreversible heat ow information can be.
Whereas polyethene has a glass transition range of. Dsc, mdsc can also be run in a cooling rather than heating mode. Differential scanning calorimetry dsc perkinelmer s dsc family a beginners guide this booklet provides an introduction to the concepts of differential scanning calorimetry dsc. Dry nylon6 has a glass transition temperature of 47 c 117 f. Schematic representation of first and secondorder transitions.
Characterization of the glass transition temperature of chitosan and its oligomers by temperature modulated differential scanning calorimetry prerna p. The temperaturemodulated dsc tmdsc technique introduced here makes it possible to acquire information that cannot be obtained with standard dsc by temperature control in which a modulation is overlaid on a constant temperature increase. The consequence of this dramatic increase is a glass exhibiting solidlike. The conventional dsc method, we measure heat flow as well as temperature, such as glass transition, crystallization, or melting, by detecting. In the modulated heatcool profile, some cooling of the sample is encountered on each modulation cycle.
Experimental parameters the key to obtaining accurate and reproducible results is the same in both conventional and modulated dsc the material being studied must be able to follow the temperature profile imposed on it. Topem, a new temperature modulated dsc technique application to the glass transition of polymers iria fraga1, s. This suggests that there is a difference in thermal hysteresis between the two samples. Modulated dsc mdsc can be easily understood by comparing it to its. Using mtdsc the enthalpic transition could be separated from the glass transition, as it was part of the nonreversing specific. Studying the glass transition by dsc and tmdsc springerlink. Subsequently, the way in which the glass transition is manifest in temperature modulated dsc is presented, and the. The generic name for all such methods is modulated temperature dsc, or mtdsc, and the name of the perkinelmer software product that supports mtdsc is stepscan. In the modulated dsc experiments, all samples were heated and cooled for several times at the rate of 2 c min 1 in a nitrogen atmosphere. Modulated temperature dsc mdsc is an extension of dsc. Temperature modulated differential scanning calorimetry tmdsc is a.
Basics and application in pharmaceutical sector article pdf available in asian journal of pharmaceutics april 2009 with 12,933 reads how we measure reads. However, the approach is challenging when probing glass samples that exhibit overlapping transitions or low sensitivity. The width of the glass transition for glycerol, taken from the. The differential scanning calorimeter dsc is a fundamental tool in thermal analysis.
Temperature modulated dsc is used to study the fragility of three different bulk metallic glass forming liquids. Investigation of polymers with di erential scanning. This paper outlines the basis for the modulated dsc technique and shows its. Temperature modulated calorimetry of glassy polymers and. Resolving glass transition in tebased phasechange materials.
The experimental technique offered by temperaturemodulated differential scanning calorimeter tmdsc used to investigate the thermal relaxation dynamics through the glass transition as a function of frequency was studied for pure pmma and. It also describes two important aspects frequency dependence and enthalpic recovery of the important glass transition measurement that can be readily determined from dsc and mdsc experiments. The transition comprises a smooth increase in the viscosity of a material by as much as 17 orders of magnitude within a temperature range of 500 k without any pronounced change in material structure. Nylon6,6 in the dry state has a glass transition temperature of about 70 c 158 f. Fengb adepartment of materials science, faculty of science, national university of singapore. Thermochimica acta 446 2006 147155 stochastic temperature modulation. Thermal characterization of glasses and polymers by temperature. The glass transition of a liquid to a solidlike state may occur with either cooling or compression.
Liquid fragility and the glass transition in water and. Jagtap department of polymer and surface engineering, institute of chemical technology, matunga, mumbai, india. By conventional dsc the extent of enthalpic relaxation was found to increase with ageing time accompanied by a shift in the apparent glass transition to a higher temperature. The temperature range may be extended depending upon the instrumentation used. Using modulated dsc mdsc to separate an enthalpic recovery from a glass transition keywords. Aalborg universitet on the frequency correction in. Astm e56, standard test method for assignment of the glass transition temperature by differential scanning calorimetry.
The format of the t g scan is similar to that of a kinetic scan except that it is performed with a cured sample. Lellingerc a mettlertoledo gmbh, sonnenbergstrasse 74, ch8603 schwerzenbach, switzerland b zurich university of applied science, p. Temperature modulated dsc for the multiple glass transition in polynalkyl methacrylates article in thermochimica acta 39112. Ta q100 differential scanning calorimeter 5 a schematic of a dsc thermogram is shown in the following figure. Standard test methods for the assignment of the glass.
Phase transition characterization by thermal analysis. The reversible and nonreversible heat ow information can be simultaneously obtained in one modulated dsc experiment. Here, the thermal characteristics of various polymer materials were evaluated by using the tmdsc technique. Advanced techniques and strategies in thermal analysis and calorimetry dsc, mdsc, tga, sa, and microcalorimetry charles potter, ph. Measurement of the glass transition and glass transition temperature are probably the most.
Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Through applying various modulation frequencies, the dynamic glass transition shifts in temperature, allowing to determine the temperature dependence of. Characterization of pharmaceutical materials by thermal. The application of temperaturemodulated dsc to the glass. Topem, a new temperature modulated dsc technique application. Volume 391, issues 12, 12 august 2002, pages 219225. Effect of trehalose on the glass transition and ice crystal growth. Figure \\pageindex32\ is an example of the glass transition as measured by dsc.
In conventional dsc, the difference in heat flow between a sample and an inert reference is measured as a function of time and temperature as both the sample and reference are subjected to a controlled environment of time, temperature, and pressure. Historical introduction today, it is well known that heat is a form of energy exchanged between systems and. Methods and data figures 2 shows the shifting of the baseline to the endothermic side due to glass transition at 60. For general mdsc experiments, and for the measurement of heat capacity or the glass transition, the modulated heatcool. Thermal characterization of glasses and polymers by. The intersection of these tangents to the tangent at the in. The theoretical modeling of the relaxation behavior of polymers in the glass transition region, advocated by moynihan and coworkers, has been used to analyze the heat flow and the relaxation of polymer systems during isothermal modulated dsc experiments in the glass transition region. Notice that this graph labels four critical points. Express 10 105601 view the article online for updates and enhancements. Introducing the temperature modulated dsc hitachi hightech in. Box 805, ch8401 winterthur, switzerland c deutsches kunststoffinstitut. For amorphous and semicrystalline materials the determination of the glass transition temperature may lead to important information about their thermal history, processing conditions, stability, progress of chemical reactions, and mechanical and electrical behavior.
Authors personal copy on the frequency correction in temperaturemodulated differential scanning calorimetry of the glass transition xiaoju guoa,b, john c. Dsc, mdsc, epoxy, glass transition, enthalpic recovery background the glass transition is the temperature range where amorphous structure undergoes a change in mobility which can have a large effect on material properties. Effect of a distribution of relaxation times an analysis of. See appendix c of the dsc 2920 operators manual for more information.
Allana, yuanzheng yueb,c, a science and technology division, corning incorporated, corning, ny 14831, usa b section of chemistry, aalborg university, dk9000 aalborg, denmark c shandong key laboratory for glass and. The curve obtained using temperaturemodulated dsc would be the same as this if a modulation frequency of 10 hz were instrumentally possible. Characterisation of the glass transition of an amorphous drug. Advanced techniques and strategies in thermal analysis and. Ta instruments differential scanning calorimeter dsc insert. Keywords glass transition differential scanning calorimetry structural relaxation heterogeneity vitri. Effect of trehalose on the glass transition and ice crystal. Characterisation of the glass transition of hpmc using. This dynamic glass transition can be distinguished from the thermal, or kinetic glass. Related content relaxation and physical aging in network glasses. The table is supplied in the help section of the online manual and greatly. Physical properties evaluation of polymer materials by. It is written for the materials scientist unfamiliar with dsc.
Standard test method for assignment of the glass transition. The experimental technique offered by temperature modulated differential scanning calorimeter tmdsc used to investigate the thermal relaxation dynamics through the glass transition as a function of frequency was studied for pure pmma and. Differential scanning calorimetry, or dsc is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. The heat capacity of the polymer is di erent before and after the glass transition temperature. Using thermal techniques for amorphous materials icdd.
The heat capacity c p of polymers is usually higher above t g. Effect of trehalose on the glass transition and ice. Characterization of pharmaceutical materials by thermal analysis l. Characterisation of the glass transition of an amorphous. Probing the glass transition in reversible crosslinked. Determination of the glass transition temperature methods correlation and structural heterogeneity john m. Pdf crystallization of polymers investigated by temperature. Some possible transitions in a dsc curve temperature glass transition crystallization polymorphic conversion. The glass transition has been highlighted, and the glass transition temperature is understood to be the midpoint of the transitional range. Accepted manuscript determining the fragility of bulk. Modulated temperature differential scanning calorimetry mtdsc is a capability for determining. The technique is based on stochastic tem perature modulation and has been developed as a consequence of a generalized theory of a temperature modulated dsc. Temperature modulated dsc for the multiple glass transition. In particular, the effects of measuring variables temperature cycling, scanning period, heating mode have been examined.
The glass transition is manifested as a step change in specific heat capacity. The temperature modulated dsc tm dsc technique introduced here makes it possible to acquire information that cannot be obtained with standard dsc by temperature control in which a modulation is overlaid on a constant temperature increase. Parametric study of temperaturemodulated differential. A new temperature modulated differential scanning calorimetry tmdsc technique is introduced.
732 184 142 1499 399 1358 832 1249 1415 410 261 1460 1230 1388 175 409 314 352 644 515 1268 278 530 547 1273 686 1129 1130 801 1401 1134 476 1254 378 1345 303 32 546 1152 160 397 1081 1081 361