Abstract
Previous comparative studies on the impact of cryogenic mechanical mil領(lǐng) (CMM) of polymers showed significantly changed thermal and
mechanical properties andin the case of some polymer blends (e.g., PMMA/PVDF) an improved miscibility. Those changes were mainly
attributed to a reduction of the molecular weight average during the mil領(lǐng) process.
The crystallization process in macromolecular systems is strongly affected by any small change of the initial chain structure like the chain
conformation, the presence of branches and of course a decrease of the molecular weight average. Therefore, the aim of this paperwas a comparative
study of isothermal crystallization of cryogenic mechanically milled and original (unmilled) polymers and polymer blends. The overall crystal
growth rates were determined and the development of the spherulitic morphology was studied in detail by means of hot stage polarized light
microscopy. Isothermal crystallization of bulk samples was also investigated using differential scanning calorimetry (DSC).
The average spherulite growth rates of the milled homo-polymer as well as the blends were significantly higher than in unmilled samples; even
when all experiments started from the molten state. Moreover, the increase in crystal growth was almost independent of the chosen crystallization
temperature and thus the degree of undercoo領(lǐng).
© 2006 Elsevier B.V. All rights reserved.
Keywords: Cryogenic mechanical mil領(lǐng); PVDF; Blends; Crystallization SPEX6770 全自動冷凍研磨機 SPEX6870 全自動冷凍研磨機 SPEX6970EFM 冷凍研磨機
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