Exploring DSC Graphs and Applications in Teaching Laboratories

[rmiller70015]

I have been asked to find a way to integrate our DSC instrument into a teaching laboratory. I have read through some articles on the Journal of Chemical Education and I have a good idea on what to do as far as content goes, but there are some particulars about the instrument that I'm unsure of. So, I figured I'd see if anyone had some good sources available.

I know that you can find practical handbooks for instrumental techniques such as GC, NMR, Mass Spec, etc. I was wondering if anyone had a good handbook like that. Also I was wondering if there were books with graphs from pure substances. Again similar to the spectra books for NMR, Mass Spec, UV-Vis, IR, etc.

In particular what I am looking for are what exactly the integral and derivative of the graph can tell us, how to use baselines, any effects on changing the purge gas outside of what is discussed in the users manual (mostly about the oxidation of samples and sample pans), what the heat history of a polymer can tell us, and graphs of pure substances like polymers (synthetic fibers, plastics from wiring or trash bags, and other plastics that might commonly be found in a crime scene), also the graphs of animal and plant fibers (hopefully furs or plant fibers used in clothing, and common pet furs).

If you've got some titles I'd really appreciate to hearing about them.

 

[TeethWhitener]

This looks promising:

http://polymerdatabase.com/polymer physics/GlassTransition.html

 

[Kevin McHugh]

Are polymers your main area of interest? DSC is basically just a fancy melt point apparatus. Although it can be used to follow the changes in enthalpy of reactions. I've used DSC to calculate the content of polymer blends such as LDPE/LLDPE, LDPE/HDPE, LDPE/LLDPE, etc. I've also used it to differentiate nylon 6 and nylon 66, and PBT and PET. It is useful for glass transitions of styrenics. What is you ultimate goal for this machine?

 

[rmiller70015]

Are polymers your main area of interest? DSC is basically just a fancy melt point apparatus. Although it can be used to follow the changes in enthalpy of reactions. I've used DSC to calculate the content of polymer blends such as LDPE/LLDPE, LDPE/HDPE, LDPE/LLDPE, etc. I've also used it to differentiate nylon 6 and nylon 66, and PBT and PET. It is useful for glass transitions of styrenics. What is you ultimate goal for this machine?

Well I am at a University and the forensic chemistry department is getting worked over and they want to expose students to DSC since it has become so prevalent. However, no one knows how to use the instrument and I've been asked to figure it out. So, I've decided that the best way is to perform a fiber analysis for fibers that may be commonly found on crime scenes. I was thinking that I students would receive fibers of an unknown origin and some standard fibers for analysis to compare the curves against. And verify the analysis with IR or light microscopy (not necessarily in that order).

Since I posted, I've also found a few great resources. Thermal Analysis of Polymers by Menczel, J.D. and Prime, R.B. from Wiley and Sons has a good bit of information on the theory behind a wide range of thermal analysis techniques. Also there is Thermal Characterization of Polymeric Materials by E.A. Turi, but I haven't gotten to it yet so I don't know how good it is. Also, as I recall Mettler-Toledo has UserComs 11-13, these have a good deal of information on interpretations of curves and what has been done recently with their instruments, this is available for free as a PDF.

 

[Kevin McHugh]

DSC would be great for fiber analysis. Most fibers are nylon, polyester, polypropylene. If you have means of compounding plastic, you can make polymer blends of known weight percent, and develop calibration curves for polymer blends.