Fractionated crystallization and self‐nucleation behavior of poly(ethylene oxide) in its miscible blends with poly(3‐hydroxybutyrate)

Abstract

ABSTRACT:The fractionated crystallization and selfnucleation behavior of poly(ethylene oxide) (PEO) component in the miscible PEO/poly(3-hydroxybutyrate) (PHB) binary blends were investigated using differential scanning calorimetry (DSC) and small-angle X-ray diffraction (SAXS) under different crystallization conditions. The distribution of PEO component in the PEO/PHB blend greatly influences its fractionated crystallization behavior. The active heterogeneities, on which the semicrystalline components in the molten state can nucleate at a small supercooling, are favored to locate out of the interlamellar regions of PHB crystals during the crystallization of PHB component. The PEO component confined in the interlamellar regions of PHB crystals crystallizes at an extremely large supercooling, which is induced by the homogeneous nucleation or less active heterogeneities, while the PEO component expelled out of the interlamellar regions of PHB crystals can crystallize at a small supercooling due to the nucleation induced by active heterogeneities. In addition, the self-nucleation behavior of PEO component in the PEO/PHB blend is also affected by the active heterogeneities and the distribution of PEO phase in the blend. Different from the block copolymer systems, the PEO component confined into the interlamellar regions of PHB crystals can not be selfnucleated in the PEO/PHB blend without a nucleating agent (NA).

Nucleation and Self‐Nucleation of Bio‐Based Poly(ethylene 2,5‐furandicarboxylate) Probed by Fast Scanning Calorimetry

“…PEF self‐nucleation behavior was investigated by FSC measurements using an experimental approach which was first described by Fillon et al for DSC analysis and which was widely employed afterward . The self‐nucleation technique proposed consists in heating a previously crystallized sample to a certain temperature close to the polymer melting point, namely the self‐nucleation temperature, T s .…”

Crystalline and Spherulitic Morphology of Polymers Crystallized in Confined Systems

“…Researchers have found that the binary miscible crystalline/crystalline polymers show the confined and fractional crystallization behavior because of the phase separation and segregation in different length scales during crystallization process. These crystalline/crystalline polymer blends included poly(ethylene terephthalate) (PET)/poly(butylene terephthalate) (PBT) [75], poly(3-hydroxybutyrate) (PHB)/poly(ethylene oxide) (PEO) [76,77], poly(vinylidene fluoride) (PVDF)/poly(butylene adipate) (PBA) [78][79][80], PVDF/poly(butylene succinate-co-butylene adipate) (PBSA) [81], PVDF/PHB [82], PVDF/poly(butylene succinate) (PBS) [83][84][85], PBS/PEO [86][87][88][89][90][91][92], PBS/PBA [93,94], poly(butylene adipate-co-butylene succinate) (PBAS)/PEO [95], poly(ethylene succinate) (PES)/PEO [96], PLLA/poly(oxymethylene) [97,98], and so on. Expect for the miscible blends with one or two crystalline homopolymers, the miscible copolymer/copolymer blends having crystalline components or blocks could also show the confined crystallization behavior [99,100].…”

Polymorphic crystallization of poly(butylene adipate) and its copolymer: Effect of poly(vinyl alcohol)

“…It is interesting that the polymer particle had a higher T c than the corresponding bulk sample; this was indicative of the faster crystallization of the former. This contradicted the general theory of confined crystallization, in which the crystallization rate of a polymer confined in a nanometer‐scaled environment is usually decreased because of the difficulty of heterogeneous nucleation …”