Morphology of Form I′ crystals of polybutene-1 formed on melt-crystallization

Stolte, Isabell; Fischer, Matthias; Roth, Robert; Borreck, Sven; Androsch, René

doi:10.1016/j.polymer.2015.02.034

Cited by 21 publications

(18 citation statements)

References 24 publications

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“…10,12−15 In addition, form I′ shows up−down disorder in side groups within the crystalline structure, as evidenced by electron diffraction measurements. 16 Besides, their crystalline morphology is different 17 and the lamellar thickness of form I′ at the same crystallization temperature is much smaller than those of form II and form I giving form I′ the lowest melting point among them. 18 The growth rate of form I′ is much lower than that of form II 19 manifesting a much higher secondary nucleation barrier on the growth crystal front for form I′ than form II.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Form I and form I′ have the same helix structure as well as a wide-angle X-ray diffraction pattern , and they are distinguished by the origin of formation, that is, form I is the one transformed from form II through a solid–solid phase transition, while form I′ directly crystallizes from the melt or solution. ,− In addition, form I′ shows up–down disorder in side groups within the crystalline structure, as evidenced by electron diffraction measurements . Besides, their crystalline morphology is different and the lamellar thickness of form I′ at the same crystallization temperature is much smaller than those of form II and form I giving form I′ the lowest melting point among them . The growth rate of form I′ is much lower than that of form II manifesting a much higher secondary nucleation barrier on the growth crystal front for form I′ than form II.…”

Section: Introductionmentioning

confidence: 99%

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Glass-Transition-Temperature-Independent Form II to I Phase Transition of Low-Molar-Mass Isotactic Polybutene-1

Liu

Men

2021

Macromolecules

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Temperature-dependent form II to I transition in isothermally crystallized low-molar-mass polybutene-1 has been investigated by means of fast scanning calorimetry. The ascrystallized sample possesses metastable form II crystals with a wide distribution of lamellar thickness and thus a wide distribution of the density of intercrystalline links between adjacent lamellae due to the high mobility of the chain segments within form II crystals and a limited chain length (low molar mass). Upon annealing the as-crystallized sample at different temperatures, the form II to I transition was found to occur in a wide temperature range irrespective of the glass transition temperature. The form I crystals transformed below glass transition possess a higher melting point than those transformed at a temperature close to the crystallization temperature. The results indicate that those lamellae with less or no intercrystalline links are not restricted by the vitrified amorphous phase. The mobility of chain segments in those well-crystallized form II crystals remains even at a temperature few tens of kelvin below the glass transition.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Glass-Transition-Temperature-Independent Form II to I Phase Transition of Low-Molar-Mass Isotactic Polybutene-1

Liu

Men

2021

Macromolecules

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“…Since the nucleation of the stable Form I occurs much more rarely in bulk crystallization than that of the predominant Form II, it can only be obtained through solid‐solid transition from Form II. However, Form I′, described as a defective Form I with lower melting temperature, can be formed through special crystallization procedures, such as solution crystallization, blending with iPP, or copolymerization with other monomers . Actually, quiescent aging at room temperature of Form II samples is generally used for generating trigonal Form I, where the molecular conformation of the chains is that of a 3/1 helix …”

Section: Introductionmentioning

confidence: 99%

Cross‐nucleation of polybutene‐1 Form II on Form I seeds with different morphology

Wang

Carmeli

et al. 2020

Polymer Crystallization

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Polybutene-1 (PB-1) trigonal Form I crystals with different morphologies, namely spherulitic, hedritic, and fibrous, were used as seeds to quantitatively study the cross-nucleation kinetics of the tetragonal Form II. Interestingly, a large difference in the cross-nucleation ability of the various Form I seeds was observed. The Form I fiber exhibits the fastest cross-nucleation, followed by the hedrite and eventually by the spherulite. The nucleation induction time was quantified from the evolution of the transmitted light intensity via polarized optical microscopy. The data were tested against different nucleation models, revealing that the rate-determining step for nucleation is the growth of the nucleus to attain the critical dimension, rather than the formation of the first crystalline layer in contact with the substrate. In addition, for spherulitic seeds, a meaningful dependence of cross-nucleation induction time on Form I lamellar thickness was found, with the kinetics being faster for higher original seed's crystallization temperatures. The results were interpreted assuming a free energy barrier for cross-nucleation which is a function of the mismatch between the daughter and the parent polymorphs' lamellar dimensions. This aspect, together with the calculated low values of interfacial free energy difference parameter for nucleation, suggests the possible existence of an epitaxial relationships between crossnucleating PB-1 Form II and Form I. K E Y W O R D Scross-nucleation, morphology, polybutene-1, polymorphism

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“…Generally, Form I′ can be obtained by several methods, such as solution crystallization, 16 blending with isotactic polypropylene 15 or copolymerization with other monomers. [17][18][19] The transformation mechanism of Form II to Form I has been investigated for several decades. On a molecular level, it has been usually considered that the chirality of the 11/3 helix of Form II does not change when it transforms to Form I, which is made of 3/1 helix.…”

Section: Introductionmentioning

confidence: 99%

Promotion of Self-Nucleation with Latent Form I Nuclei in Polybutene-1 and Its Copolymer

et al. 2018

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The formation of Form I nuclei of polybutene-1 (PB-1) and its copolymer with polyethylene (PB1-ran-PE) has been studied by means of modified self-nucleation protocols. Even when the self-nucleation temperature was high enough and all Form II crystals melt, re-crystallization can be accelerated if the melt-crystallized sample was annealed at low temperatures (below 60 o C for PB-1 and 75 o C for PB1-ran-PE) for just 3 min. These results suggest the formation of latent Form I nuclei within Form II crystals. This hypothesis is consistent with the observed growth of a small amount of Form I crystals during heating, after previous annealing at temperature lower than 20 °C.In addition, a peculiar phenomenon was found in PB1-ran-PE, as both Form II and Form I′ can be induced by the presence of latent Form I nuclei, due to cross-nucleation and self-nucleation effects, respectively. The final ratio of the two kinds of crystal Forms is a result of the competition between the two nucleation rates, which strongly depend on crystallization temperature. In this work, we have shown that careful design of novel self-nucleation protocols can yield evidence of the early stages of Form II to Form I transition, even when the degree of transformed crystals is below the limit of detection of conventional techniques sensitive to crystalline order (DSC, WAXD, FTIR).

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Morphology of Form I′ crystals of polybutene-1 formed on melt-crystallization

Cited by 21 publications

References 24 publications

Glass-Transition-Temperature-Independent Form II to I Phase Transition of Low-Molar-Mass Isotactic Polybutene-1

Glass-Transition-Temperature-Independent Form II to I Phase Transition of Low-Molar-Mass Isotactic Polybutene-1

Cross‐nucleation of polybutene‐1 Form II on Form I seeds with different morphology

Promotion of Self-Nucleation with Latent Form I Nuclei in Polybutene-1 and Its Copolymer

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