Abstract
The courses of phenomena occurring in investigated plastics during heating were studied. The plastics specimens have been subjected to investigation before and after heating. Two kinds of plastics being applied in machine constructions Tarnamid T-27 (polyamide 6) and Tarnoform 300 (polyacetale) have been chosen to investigation.
The specimens have been subjected to heat treatment in turbine oil at minimum temperature of crystallization: polyamid 6 at 170°C and polyacetal at 140°C. It has been found that during heating in tested plastics endo- and exothermic effects take place and there are some differences for plastics before and after heating. It is possible to calculate the grade of crystallinity on the base of DTA curves. In polyamid 6, in which the polymorphic transformation takes place, the known methods of calculation of degree of crystallinity proves ineffective.
Plastics after heating characterize the higher degree of crystallinity grade.
Zusammenfassung
Es wird untersucht, welche Erscheinungen beim Erhitzen von zwei im Maschinenbau verwendeten Plasten, d.h. von Tarnamid T-27 (Polyamid 6) und von Tarnoform 300 (Polyacetal) auftreten und wie sich die Wärmebehandlung auf die Eigenschaften der untersuchten Plaste auswirkt.
Die Proben wurden in Turbinenöl auf die Mindest-Kristallisationstemperatur erhitzt: bei Polyamid 6 auf 170°C, bei Polyacetal auf 140°C. Man fand, daß beim Erhitzen in den untersuchten Plasten einige endo- und exotherm Effekte auftreten und daß einige Unterschiede zwischen Plasten vor und nach der Wärmebehandlung bestehen. Anhand der DTA-Kurven kann der Kristallinitätsgrad berechnet werden. In Polyamid 6, wo polymorphe Umwandlungen stattfinden, erwiesen sich die bekannten Methoden zur Berechnung des Kristallinitätsgrades als uneffektiv.
Die Plaste werden nach der Wärmebehandlung durch einen höheren Kristallinitätsgrad gekennzeichnet.
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Koszkul, J. The application of differential thermal analysis to investigation of thermoplastics. Journal of Thermal Analysis 38, 2311–2323 (1992). https://doi.org/10.1007/BF02123984
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DOI: https://doi.org/10.1007/BF02123984