logging in or signing up DTA& DSC samaju Download Post to : URL : Related Presentations : Let's Connect Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 4683 Category: Education License: All Rights Reserved Like it (11) Dislike it (2) Added: September 18, 2010 This Presentation is Public Favorites: 4 Presentation Description No description available. Comments Posting comment... By: dhaneha (5 month(s) ago) cn yu plz snd me more details abt dsc Saving..... Post Reply Close Saving..... Edit Comment Close By: nitinkashyap9256 (13 month(s) ago) i have details about dsc. shall i send you?? Saving..... Post Reply Close Saving..... 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Thermal methods of analysis : Thermal methods of analysis Technique in which some physical parameters of the system is determined and recorded as a function of temperature. Differential thermal analysis (dta) : Differential thermal analysis (dta) Introduction: Records the difference in temperature between a substance and a reference material against time or temperature . Thermal changes due to fusion, crystalline structure inversions, boiling, decomposition, oxidation, reduction, destruction of crystalline lattice structure etc. are generally accompanied by rise or fall in temperature. phase transitions, dehydration, reduction produce endothermic effects. crystallization, oxidation produce exothermic effects. Slide 4: DTA curve: Endotherms are plotted downwards and exotherms upwards. The temperature of the sample is greater for an exothermic reaction, than that of the reference; for endotherms the sample temperature lags behind that of the reference. Area of the peak is proportional to the amount of reacting material. Slide 5: Factors Affecting DTA Curve: Slide 6: Instrumentation: Furnace Assembly Sample and reference holder with temperature detector Temperature programmer Amplifier and recorder Atmosphere control equipment for furnace and sample holder Slide 7: Applications: Identification of substances Identification of products Melting points Quantitative analysis Quality control Analysis of biological materials Inorganic and Organic chemistry. Differential scanning calorimetry(dsc) : Differential scanning calorimetry(dsc) Slide 9: Introduction: Advantage of keeping the sample and reference at the same temperature and heat flow into sample and reference is measured. Achieved by placing separate heating devices in the sample and reference chambers. In DSC the heat flow is measure and plotted against temperature of furnace or time to get a thermogram. Curve obtained in DSC is between dH/dt in mJ s-1 or mcal s-1 as a function of time or temperature. Slide 10: DSC curve: The area under the peak is directly proportional to the heat evolved or absorbed by the reaction, and the height of the curve is directly proportional to the rate of reaction. Slide 11: Factors affecting DSC curve: Instrumental factors: a) Furnace heating rate. b) Recording or chart speed c) furnace atmosphere d) Geometry of sample holder/ location of sensors e) Sensitivity of recording mechanism. f) Composition of sample container. 2. Sample Characteristics: a) Amount of sample b) Solubility of evolved gases in sample. c) Particle size d) Heat of reaction e) Sample packing f) Nature of sample g) Thermal conductivity. Slide 12: Instrumentation: Slide 13: Types of DSC instruments: Slide 14: Applications: Slide 15: Parameters measured by DSC: Melting and boiling points Crystallisation time and temperature Percent crystallinity Heats of fusion and reactions Specific heat capacity Oxidative/thermal stability Rate and degree of cure Reaction kinetics Purity references : references H.H.Willard , L.L.Merrit Jr., J.A. Dean , F.A.Settle Jr., Instrumental Method of Analysis, Wadsworth Publishing company , USA, 1986. Skoog, Douglas A., F. James Holler and Timothy Nieman, Principles of Instrumental Analysis. Fifth Edition. New York. 1998. Gurdeep R Chatwal, Sham K. Anand., Instrumental Methods of Chemical Analysis. Fifth edition.2007 You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.