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Isothermal Crystallization of Isotactic Poly(propylene) Studied by Superfast Calorimetry
Author(s) -
Silvestre Clara,
Cimmino Sossio,
Duraccio Donatella,
Schick Christoph
Publication year - 2007
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200600844
Subject(s) - crystallization , materials science , tacticity , nucleation , differential scanning calorimetry , isothermal process , polymer chemistry , calorimetry , kinetics , chemical engineering , crystallography , thermodynamics , composite material , polymer , polymerization , chemistry , physics , engineering , quantum mechanics
The isothermal crystallization behavior and the structure and morphology of isotactic poly(propylene) (iPP) and iPP/hydrogenated hydrocarbon resin (HR) 90/10 blend were analyzed. To cover the entire temperature range, isothermal crystallizations were studied using superfast calorimetry at a high cooling rate in the range 0 to 110 °C, and by conventional DSC at a low cooling rate in the range 120 to 140 °C. Structural and morphological changes due to the different thermal treatments were also analyzed. The complete crystallization curve ranging from T g to T m showed bimodal crystallization behaviors for both iPP and iPP/HR 90/10 blend. This result is explained by taking into consideration the polymorph properties of iPP. It is in fact assumed that the curve from T g to 60 °C referred mainly to the crystallization kinetics of the iPP mesomorphic form by homogeneous nucleation, whereas the curve from 60 °C to T m mainly represented the crystallization kinetic curve for the monoclinic α form by heterogeneous nucleation. This hypothesis is confirmed by the analysis of the structures obtained using wide angle X‐ray experiments. Moreover, the addition of HR to iPP causes a drastic reduction in the crystallization rate of iPP in both regions due to the diluent effect of the miscible resin.