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

Wang, Wei; Wang, Bao; Carmeli, Enrico; Wang, Zefan; Ma, Zhe; Cavallo, Dario

doi:10.1002/pcr2.10104

Cited by 4 publications

(18 citation statements)

References 65 publications

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“…The PB-1 pellets were first compressed into films with a thickness of about 0.30 mm in the melt state. Then, the thin film was heated to 180 °C in a Mettler hot-stage, kept at this temperature for 5 min to erase thermal history, and further cooled to 108 °C for isothermal crystallization for 2 h to obtain an hedrite of form II . The sample was then quickly quenched to room temperature causing the formation of numerous smaller crystals with low melting temperature.…”

Section: Methodsmentioning

confidence: 99%

“…Then, the thin film was heated to 180 °C in a Mettler hot-stage, kept at this temperature for 5 min to erase thermal history, and further cooled to 108 °C for isothermal crystallization for 2 h to obtain an hedrite of form II. 36 The sample was then quickly quenched to room temperature causing the formation of numerous smaller crystals with low melting temperature. Finally, the sample was stored at room temperature for more than 1 month to completely transform the original form II hedritic crystals into form I.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Although cross-nucleation is encountered in several polymorphic polymers as well, − whether epitaxy plays a prominent part in it is still unclear. The case of isotactic polypropylene is emblematic because an epitaxial relationship for α-phase single crystals nucleating at the surface of a β-phase crystal has been proposed by Lotz, but it has been shown to not hold in bulk samples …”

Section: Introductionmentioning

confidence: 99%

“…Of particular interest, also for its cross-nucleation behavior, is polybutene-1 (PB-1), which exhibits pronounced polymorphism that can be distinguished by the chain conformation and packing mode of segmental stems . Different helical conformations, that is, the 3/1, 11/3, and 4/1 helixes, can pack into trigonal (form I), tetragonal (form II), and orthorhombic (form III) unit cells. , Among them, the form I unit cell parameters are a = b = 17.5 Å, c (chain axis) = 6.477 Å, and γ = 120° (with space group P 3̅), while form II exhibits a tetragonal unit cell with the parameters a = b = 14.9 Å and c = 21.3 Å (with space group P 4̅ b2 ). − The kinetically favored, metastable form II can transform slowly and spontaneously into the stable form I at room temperature. , The transformation is greatly accelerated by the presence of mechanical stresses. , Thanks to the solid-state phase transition, seeds of form I into a PB-1 melt can be created, and form II was demonstrated to cross-nucleate on the surface of such seeds. , Our previous work has revealed that the cross-nucleation efficiency of form II on form I substrates increases with the thickening of form I lamellae, a fact that was interpreted as a possible hint of an epitaxial relationship between the two structures . Therefore, we now aim to further explore and resolve this issue by employing a nanofocused synchrotron X-ray beam on a cross-nucleated PB-1 sample.…”

Section: Introductionmentioning

confidence: 99%

“…32,33 Our previous work has revealed that the cross-nucleation efficiency of form II on form I substrates increases with the thickening of form I lamellae, a fact that was interpreted as a possible hint of an epitaxial relationship between the two structures. 36 Therefore, we now aim to further explore and resolve this issue by employing a nanofocused synchrotron X-ray beam on a cross-nucleated PB-1 sample.…”

Section: ■ Introductionmentioning

confidence: 99%

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Epitaxy in Polybutene-1 Form II-on-Form I Cross-Nucleation Revealed by Nanofocused X-ray Diffraction on Ad Hoc Morphology

Wang

Looijmans

et al. 2021

Macromolecules

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The existence of epitaxy in polybutene-1 form IIon-form I cross-nucleation was investigated by nanofocused synchrotron X-ray diffraction. To this aim, form I hedrites, which show a lamellar stacking with a uniform crystal lattice orientation, were adopted as the substrate. The form II crystals develop a spherulitic transcrystalline layer on the lateral surface of the form I substrate, due to cross-nucleation. Through mapping both the intensity and azimuthal orientation of characteristic planes of the two polymorphs, a clearly defined nucleation area between form II (daughter) and form I (parent) could be identified. Comparing the two-dimensional diffraction patterns in that area, a preferred mutual orientation of the two structure is revealed. In particular, the (200) II plane of form II and the (110) I plane of form I are reciprocally oriented at a fixed angle of ∼8.5°. This orientation results in almost parallel (110) planes between the two structures. It is calculated that the mismatch between interchain distances within the common ( 110) planes is about 4%, while that along the chain axes is less than 10%, both well below the accepted mismatch criterion for epitaxial crystallization. These results provide solid evidence for the existence of an epitaxial relationship in the cross-nucleation between polybutene-1 form II and form I. We note that the (110) contact plane between the two structures in cross-nucleation is the same as the one involved in the well-studied solid-state phase transformation from form II to form I. Moreover, the X-ray nanofocus approach and the proposed data analysis could be effectively applied to other cross-nucleating systems to shed light on the role of epitaxy in this peculiar phenomenon of nucleation between polymorphs.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Epitaxy in Polybutene-1 Form II-on-Form I Cross-Nucleation Revealed by Nanofocused X-ray Diffraction on Ad Hoc Morphology

Wang

Looijmans

et al. 2021

Macromolecules

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Surface Nucleation of Dispersed Droplets in Double Semicrystalline Immiscible Blends with Different Matrices

Wang

Buzzi

Fenni

et al. 2022

Macro Chemistry & Physics

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When a minor semicrystalline phase is dispersed in an immiscible blend with another polymer in the form of isolated droplets, its crystallization behavior is dominated by nucleation. In particular, nucleation can occur in the bulk volume of the phase (homogeneous nucleation), at the surface of possible nucleating foreign impurities, or at the interface with the matrix polymer. Dispersed poly(butene-1) (PB) and polycaprolactone (PCL) droplet phases are employed in various matrices (isotactic polypropylene (iPP), high density polyethylene (HDPE), poly(vinylidene fluoride) (PVDF) and poly(butylene succinate) (PBS)). The effect of matrix self-nucleation on the crystallization of the dispersed droplet phase is then probed. It is shown for all the investigated polymer blends that increasing the matrix crystallization temperature (T c ) via self-nucleation favors droplet nucleation at the interface, leading to a corresponding increase in the droplets'; T c . Interestingly, distinct nucleation effects are observed when different polymer matrices are compared. The highest nucleating efficiency is displayed by the polymer pairs, which are known to exhibit epitaxial crystallization from previous literature, namely PB/iPP and PCL/HDPE. The order of nucleation efficiency of the other matrices is thought to be linked with the extent of crystallographic matching between the substrate and nucleating crystals.

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Origin of Transcrystallinity and Nucleation Kinetics in Polybutene-1/Fiber Composites

et al. 2020

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This work presents an in-depth study of fiber-induced nucleation and crystalline morphology in polybutene-1/single-fiber composites. The nucleation ability of various fibers, including carbon, glass, polypropylene (PP), poly(l-lactide) (PLLA), and stereocomplex (SC)-poly(lactide), is investigated via polarized optical microscopy. A polybutene-1 (PB-1) fiber made of the trigonal Form I polymorph is also adopted in an all-PB-1 composite. Two different types of morphologies of PB-1 Form II developed on the surface of the different fibers during isothermal crystallization. They are a transcrystalline layer (TCL) on the Form I fiber only and a hybrid shish–calabash (HSC) on all of the other fibers. Upon nonisothermal crystallization, a transition from the HSC to TCL morphology for the sole PP fiber is found. Quantitative studies of nucleation kinetics showed that the lowest nucleation free-energy barrier is exhibited by the PB-1 Form I fiber, due to the occurrence of cross-nucleation with Form II, possibly via epitaxial matching. On the other hand, the highest nucleation energy barrier is that of the PP fiber, despite the very similar chemical constitution. Moreover, a large variation in the pre-exponential factor of the nucleation rate among the various fibers suggests major differences in the available nucleation sites per unit area. The number of such sites is found to inversely correlate with surface roughness and, for the first time, is used to understand the obtainable morphology. In fact, we show that, notwithstanding the height of the free-energy barrier for nucleation, TCL can only be obtained when a sufficiently high number of nucleation sites are provided.

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

Cited by 4 publications

References 65 publications

Epitaxy in Polybutene-1 Form II-on-Form I Cross-Nucleation Revealed by Nanofocused X-ray Diffraction on Ad Hoc Morphology

Epitaxy in Polybutene-1 Form II-on-Form I Cross-Nucleation Revealed by Nanofocused X-ray Diffraction on Ad Hoc Morphology

Surface Nucleation of Dispersed Droplets in Double Semicrystalline Immiscible Blends with Different Matrices

Origin of Transcrystallinity and Nucleation Kinetics in Polybutene-1/Fiber Composites

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