Phase Transition from Tetragonal Form II to Hexagonal Form I of Butene-1/4-Methyl-1-pentene Random Copolymers: Molecular Factor versus Stretching Stimuli

Zheng, Lirong; Liu, Long; Shao, Chunguang; Wang, Wei; Wang, Bin; Pan, Li; Li, Yuesheng; Ma, Zhe

doi:10.1021/acs.macromol.8b02600

Cited by 53 publications

(66 citation statements)

References 70 publications

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“…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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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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“…However, recent investigation seems to support the latter one. It was found that the stress dominating the phase transition is the stress perpendicular to the helical stem …”

Section: Discussionmentioning

confidence: 99%

“…Even, they found that without annealing at a lower temperature, form II could also transform to form I rapidly in a low molecular weight of PB‐1 synthesized by themselves, which chain was too short to form intercrystalline links . Moreover, Ma et al found that the stress dominating the phase transition was not the stress parallel to the normal direction of the lamellar stack but the stress perpendicular to the normal direction . Seemingly, these findings are completely contrary to the classical view.…”

Section: Introductionmentioning

confidence: 94%

“…Nevertheless, the role of intercrystalline links was questioned recently . Qiao et al found that intercrystalline links might retard phase transition in the later stage .…”

Section: Introductionmentioning

confidence: 99%

“…A majority of past works were based on wide‐angle X‐ray diffraction (WAXD) and differential scanning calorimetry (DSC), because they can discriminate form I from form II easily. Nevertheless, the information obtained from these tools is normally trivial.…”

Section: Introductionmentioning

confidence: 99%

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In situ POM and FTIR investigation on quiescent phase transition of polybutene‐1 from form II to form I

Ding

Zheng

et al. 2020

Polymer Crystallization

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Despite extensive investigations in the past decade, the factors affecting the phase transition of polybutene‐1 (PB‐1) form tetragonal form II to hexagonal form I were not clarified completely. In this study, quiescent phase transitions of PB‐1 within different morphological of crystals at different temperatures were investigated employing polarized optical microscopy and Fourier transform infrared spectroscopy. Results indicate that the phase transition depends not only on intercrystalline links but also on the lamellar thickness. The phase transition always occurs spontaneously first in thick form II lamellae. The intercrystalline links have opposite effects in the early and later stages. In the early stage, it can promote form I nucleation in some form II clusters, where these clusters were subjected to inward tensions of intercrystalline links. While in the later stage, it retards form I growth since subjecting to outward tensions of intercrystalline links. This study helps to identify more effective method to accelerate forms II‐I phase transition.

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Crystallization and Phase Transition of 1‐Butene Copolymers with Distinct Cyclic Co‐Units

Liu

Lou

et al. 2022

Chin. J. Chem.

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Comprehensive Summary The dimethylpyridylamidohafnium catalyst was used to synthesize 1‐butene/cyclohexene and 1‐butene/vinylcyclohexane random copolymers, which have extra six‐membered cyclic co‐units in main chain and side chain, respectively. For the obtained copolymers of different incorporations, the crystallization from amorphous melt and the solid phase transition from tetragonal to trigonal phases were investigated with differential scanning calorimetry. Both of the incorporated cyclic co‐units decrease the crystallization kinetics, but the presence of cyclohexene keeps the melting temperature of copolymers constant. Interestingly, the strong memory effect of crystallization can appear at the elevated temperature even above the equilibrium melting temperature, as the content of co‐units was increased. The 1‐butene/vinylcyclohexane copolymer with 1.52 mol% co‐units exhibits a rather strong memory effect with the broad Domain IIa width of 43°C and the crystallization temperature raising of 24°C. Furthermore, the transition of tetragonal phase into trigonal phase was also explored for different co‐units and incorporations. It was found that both of the cyclohexene co‐units and vinylcyclohexane co‐units effectively slow down the kinetics of phase transition. However, the vinylcyclohexane co‐units have a much higher efficiency in suppressing phase transition than the cyclohexene co‐units, where 0.53 mol% vinylcyclohexane can completely stop phase transition within 1320 h. Considering the fact that copolymers with vinylcyclohexane co‐units actually have lower glass transition temperatures, it was indicated that the suppression of phase transition is also largely influenced by the steric co‐units in the side chain for the helical and positional adjustments, not only by the segmental mobility.

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Phase Transition from Tetragonal Form II to Hexagonal Form I of Butene-1/4-Methyl-1-pentene Random Copolymers: Molecular Factor versus Stretching Stimuli

Cited by 53 publications

References 70 publications

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

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

In situ POM and FTIR investigation on quiescent phase transition of polybutene‐1 from form II to form I

Crystallization and Phase Transition of 1‐Butene Copolymers with Distinct Cyclic Co‐Units

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