It was bioplastic data, i want to know about the heat resistance of my bioplastic
Dear Mr. Hanjani
From your DSC curve data, we can say:
1) The peak shown cannot be a Tg because then it would be only a baseline displacement, which obviously is not the case. In fact, it is a peak which represent the melting of the polymer because it is an endothermic transition (the Y-axis states Endo up).
2) The melting temperature, set by the maximum in the peak (calculated by the DSC software) is approximately 167 degree C, which fits quite well to isotactic polypropylene. But there are two problems in the curve/data:
2a) A melting peak of a semi-crystalline polymer is usually an asymmetric curve having its wider side to the lower temperature, which is not the case. Please check if the direction of the X-axis is correct.
2b) The calculated change in the enthalpy (Delta H) is quite high 286 J/g. The melting enthalpy of the crystalline phase of PP is 207J/g. The only polymer I know having a so high value (apart from polyethylene 293 J/g) is polyoxymethylene (known also as polyformaldehyde or polyacetal) of 330J/g, but its melting temperature is 175degree C, a bit far from the displaced value. Have you calibrated the temperature scale of your DSC using metallic indium recently? If not please do it.
3) Finally calibrated again your DSC and run your sample again against known standard samples like pure HDPE, PP, Poliacetal, … To have an example of Tg curve shape run a sample of pure polystyrene, it will show up around 100 degree C.
Hope I have helped….. please give your feedback on this regard.
Sebastian
PS.: More information you may find in the book “CANEVAROLO, S. V. – “Polymer Science. A textbook for polymer engineers”, Hanser Publications, hardcover ISBN: 978-1-56990-725-2, e-book ISBN: 978-1-56990-726-9, 1st ed., 369pg, 2019, available at Amazon.com
Thank you for the answer. There are many kinds of sample result, the temperature range is 165 to 200, and 165 is the most stable.
seems like the direction is correct, the first figure i used origin software, and the second one from DSC software.
and it is a bit confusing because on TGA the result the major decomposition happen at the temperature range of 173 to 265, from what i read usually the temperature range of TGA and DSC was around same range of temperature, right ?
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