Investigation of polymers with di erential scanning. Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Effect of trehalose on the glass transition and ice crystal. In the modulated heatonly profile, the modulated temperature solid line never decreases, i. The format of the t g scan is similar to that of a kinetic scan except that it is performed with a cured sample. 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. The differential scanning calorimeter dsc is a fundamental tool in thermal analysis. 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. Authors personal copy on the frequency correction in temperaturemodulated differential scanning calorimetry of the glass transition xiaoju guoa,b, john c. Phase transition characterization by thermal analysis. Resolving glass transition in tebased phasechange materials by modulated differential scanning calorimetry to cite this article. Determination of the glass transition temperature core. Introduction measurement of the glass transition and glass transition temperature are probably. 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.
The reversible and nonreversible heat ow information can be simultaneously obtained in one modulated dsc experiment. Basics and application in pharmaceutical sector article pdf available in asian journal of pharmaceutics april 2009 with 12,933 reads how we measure reads. Some possible transitions in a dsc curve temperature glass transition crystallization polymorphic conversion. Related content relaxation and physical aging in network glasses. Liquid fragility and the glass transition in water and. 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. Modulated dsc mdsc can be easily understood by comparing it to its. Differential scanning calorimetry dsc perkinelmer s dsc family a beginners guide this booklet provides an introduction to the concepts of differential scanning calorimetry dsc. Parametric study of temperaturemodulated differential. Temperature modulated dsc is used to study the fragility of three different bulk metallic glass forming liquids. 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.
The glass transition has been highlighted, and the glass transition temperature is understood to be the midpoint of the transitional range. Pdf relaxation dynamics of glass transition in pmma. Physical properties evaluation of polymer materials by. Introducing the temperature modulated dsc hitachi hightech in. 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. Historical introduction today, it is well known that heat is a form of energy exchanged between systems and. The conventional dsc method, we measure heat flow as well as temperature, such as glass transition, crystallization, or melting, by detecting.
This dynamic glass transition can be distinguished from the thermal, or kinetic glass. In particular, the effects of measuring variables temperature cycling, scanning period, heating mode have been examined. 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. Using modulated dsc mdsc to separate an enthalpic recovery from a glass transition keywords. 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 crystallization of polymers investigated by temperature. Nov 03, 2009 temperature modulated dsc, abbreviated tm dsc, is an extension of the conventional dsc technique. Lellingerc a mettlertoledo gmbh, sonnenbergstrasse 74, ch8603 schwerzenbach, switzerland b zurich university of applied science, 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. 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. Characterization of the glass transition temperature of. Temperature modulated differential scanning calorimetry tmdsc is a. Volume 391, issues 12, 12 august 2002, pages 219225.
Express 10 105601 view the article online for updates and enhancements. Generally, the temperature program for a dsc analysis is designed such. Methods and data figures 2 shows the shifting of the baseline to the endothermic side due to glass transition at 60. Temperature modulated calorimetry of glassy polymers and. The glass transition of a liquid to a solidlike state may occur with either cooling or compression. Modulated temperature dsc mdsc is an extension of dsc. Characterization of the glass transition temperature of chitosan and its oligomers by temperature modulated differential scanning calorimetry prerna p. Jagtap department of polymer and surface engineering, institute of chemical technology, matunga, mumbai, india. Topem, a new temperature modulated dsc technique application to the glass transition of polymers iria fraga1, s. Determination of the glass transition temperature methods correlation and structural heterogeneity john m. Study of glass transition of metallic glasses by temperature. The heat capacity c p of polymers is usually higher above t g. 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.
Ta instruments differential scanning calorimeter dsc insert. Thermal characterization of glasses and polymers by. Characterization of pharmaceutical materials by thermal. Fengb adepartment of materials science, faculty of science, national university of singapore. Figure \\pageindex32\ is an example of the glass transition as measured by dsc. Modulated temperature differential scanning calorimetry mtdsc is a capability for determining. Whereas polyethene has a glass transition range of. The heat capacity of the polymer is di erent before and after the glass transition temperature. Dsc and modulated di erential scanning calorimetry mdsc.
The intersection of these tangents to the tangent at the in. Standard test methods for the assignment of the glass. Temperature modulated dsc for the multiple glass transition in polynalkyl methacrylates article in thermochimica acta 39112. Nylon6,6 in the dry state has a glass transition temperature of about 70 c 158 f. Study of glass transition of metallic glasses by temperaturemodulated differential scanning calorimetry mdsc z. Accepted manuscript determining the fragility of bulk. 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. Dsc, mdsc can also be run in a cooling rather than heating mode. 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. Practical tmdsc contains aspects of both phenomenologies and records the overshoot of figure 2 as a nonreversing heat flow.
Thermochimica acta 446 2006 147155 stochastic temperature modulation. Resolving glass transition in tebased phasechange materials. 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. Dry nylon6 has a glass transition temperature of 47 c 117 f. Subsequently, the way in which the glass transition is manifest in temperature modulated dsc is presented, and the. Box 805, ch8401 winterthur, switzerland c deutsches kunststoffinstitut. Temperature modulated dsc for the multiple glass transition. Figure \\pageindex32\ standard exo up heat flux dsc spectrum of the pet polymer. Through applying various modulation frequencies, the dynamic glass transition shifts in temperature, allowing to determine the temperature dependence of. Here, the thermal characteristics of various polymer materials were evaluated by using the tmdsc technique.
The curve obtained using temperaturemodulated dsc would be the same as this if a modulation frequency of 10 hz were instrumentally possible. In the modulated heatcool profile, some cooling of the sample is encountered on each modulation cycle. 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. The temperature range may be extended depending upon the instrumentation used. Thermal characterization of glasses and polymers by temperature. 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. Characterisation of the glass transition of an amorphous. Here, the thermal characteristics of various polymer materials were evaluated by using the tm dsc technique.
Studying the glass transition by dsc and tmdsc springerlink. Contrary to figures 2, which shows an endothermic peak at glass transition, figures 3 shows no such peak. This paper outlines the basis for the modulated dsc technique and shows its. Measurement of the glass transition and glass transition temperature are probably the most. Astm e56, standard test method for assignment of the glass transition temperature by differential scanning calorimetry. Tech 23 tip t glass transition g temperature for epoxies. 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. 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. Advanced techniques and strategies in thermal analysis and. Effect of trehalose on the glass transition and ice. Effect of trehalose on the glass transition and ice crystal growth. The application of temperaturemodulated dsc to the glass.
Aalborg universitet on the frequency correction in. 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. The consequence of this dramatic increase is a glass exhibiting solidlike. The reversible and nonreversible heat ow information can be. 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. The glass transition is manifested as a step change in specific heat capacity. The table is supplied in the help section of the online manual and greatly. 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. Characterization of pharmaceutical materials by thermal analysis l. This suggests that there is a difference in thermal hysteresis between the two samples.
Fengb adepartment of materials science, faculty of science, national university of singapore, blk s1a, lower kent ridge road, singapore 119260, singapore. Schematic representation of first and secondorder transitions. An analytic solution for the frequency dependent fictive temperature is obtained, which takes a particularly. Request pdf the application of temperaturemodulated dsc to the glass transition region ii.
Characterisation of the glass transition of an amorphous drug. The theory supporting modulated dsc can be easily understood by comparing it to conventional dsc. Keywords glass transition differential scanning calorimetry structural relaxation heterogeneity vitri. Advanced techniques and strategies in thermal analysis and calorimetry dsc, mdsc, tga, sa, and microcalorimetry charles potter, ph. Notice that this graph labels four critical points. 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. A new temperature modulated differential scanning calorimetry tmdsc technique is introduced. However, the approach is challenging when probing glass samples that exhibit overlapping transitions or low sensitivity. Probing the glass transition in reversible crosslinked. Understanding glass through differential scanning calorimetry. 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. For general mdsc experiments, and for the measurement of heat capacity or the glass transition, the modulated heatcool. Senior applications scientist ta instruments waters llc thanks to college of textiles north carolina state university.
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. 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. The width of the glass transition for glycerol, taken from the. Ta q100 differential scanning calorimeter 5 a schematic of a dsc thermogram is shown in the following figure. It is written for the materials scientist unfamiliar with dsc. Standard test method for assignment of the glass transition. Crystallization of polymers investigated by temperaturemodulated dsc. Characterisation of the glass transition of hpmc using. Using thermal techniques for amorphous materials icdd. Effect of a distribution of relaxation times an analysis of.
655 28 1073 573 838 1489 824 355 973 809 1568 877 151 582 440 973 935 361 1047 1143 1388 426 916 544 320 574 1353 269 601 1067 554 1014 224 578 1183 437 253 1368 621 170 1194 216