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K. Pielichowski, K. Flejtuch

RAPID COMMUNICATION: Some comments on the melting and recrystallization

of polyoxymethylene by high-speed and StepScan differential scanning calorimetry (in English)

Polimery 2004, No 7-8, 558


Summary

Melting process of polyoxymethylene (POM) was studied by both high-speed differential scanning calorimetry (DSC) and StepScan DSC. It has been observed that for high scan rate (hundreds degrees per minute) side effects as e.g. recrystallization are eliminated. POM macromolecules do not undergo reorganization and acomplete melting occurs. The influence of heating rate on the shape of melting peak has been discussed in context of metastability of polymeric crystal structures. Low heating rate facilitates recrystallization, due to molecular nucleation. Molecular nucleation exists when more defected or composed of shorter chains crystallites melt in the vicinity of high-melting polymer crystals, consisting of longer chains. These crystallites undergo nucleation and recrystallization on the existing unmelted crystals. The recrystallization process can be observed by means of modulated temperature differential scanning calorimetry, as it has been shown in this study.


Keywords: high-speed DSC, StepScan DSC, polyoxymethylene, melting, recrystallization


K. Pielichowski, K. Flejtuch

RASome comments on the melting and recrystallization of polyoxymethylene by high-speed and StepScan differential scanning calorimetry (in English)