Direct crystal growth of isotactic polybutene-1 trigonal phase in the melt: In-situ observation

Yamashita, Motoi

doi:10.1016/j.jcrysgro.2007.11.220

Cited by 17 publications

(8 citation statements)

References 23 publications

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“…Taking these into account, the average form I crystal growth rate during the II–I phase transition is estimated to be approximately 1.65 nm/min. Yamashita has studied the growth kinetics of forms II and I iPBu crystals from melt. − A growth rate of around 0.014 μm/s was reported for the form I crystals in the melt at 70 °C, which is 1/100 that of form II crystals. It is clear that the form I crystal growth rate from melt is about 500 times faster than the growth rate of form I crystal during the solid-phase transition.…”

Section: Resultsmentioning

confidence: 99%

Real-Space in Situ Study of the II–I Phase Transition of Isotactic Poly(1-butene)

et al. 2020

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A new technique has been developed for in situ study of the form II to I phase conversion of isotactic poly(1-butene) (iPBu) in real space. It can distinguish the nucleation and crystal growth processes unequivocally, especially in the early nucleation stage, which can hardly be followed by other traditionally used techniques owing to the limited amount of the transformed form I crystals. Moreover, the subsequent growth process of the form I crystals revealed by the time-dependent images taken during the transition process makes it possible to estimate the growth rate of the form I iPBu crystals during phase transition of ca. 1.65 nm/min at room temperature, which is about 500 times slower than the melt crystallization process. It has also revealed the slow-down crystal growth in the late transformation stage. All of these indicate that the technique is powerful in studying many aspects related to the II–I phase transition of iPBu.

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Section: Resultsmentioning

confidence: 99%

Real-Space in Situ Study of the II–I Phase Transition of Isotactic Poly(1-butene)

et al. 2020

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“…It has been shown that the melting status exerts remarkable influence on the polymorphism of semicrystalline polymers. The effect of melting temperature on the subsequent crystallization rests on the existence of surviving crystallites or oriented segments when a polymer is melted just above its nominal melting temperature but well below the equilibrium melting temperature [ 34 , 35 , 36 , 37 ]. Therefore, the melting status can be divided into two cases.…”

Section: Crystal Structural Control Of Ipbumentioning

confidence: 99%

Polymorphic Behavior and Phase Transition of Poly(1-Butene) and Its Copolymers

et al. 2018

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The properties of semicrystalline polymeric materials depend remarkably on their structures, especially for those exhibiting a polymorphic behavior. This offers an efficient way to tailor their properties through crystal engineering. For control of the crystal structure, and therefore the physical and mechanical properties, a full understanding of the polymorph selection of polymers under varied conditions is essential. This has stimulated a mass of research work on the polymorphic crystallization and related phase transformation. Considering that the isotactic poly(1-butene) (iPBu) exhibits pronounced polymorphs and complicated transition between different phases, the study on its crystallization and phase transformation has attracted considerable attention during the past decades. This review provides the context of the recent progresses made on the crystallization and phase transition behavior of iPBu. We first review the crystal structures of known crystal forms and then their formation conditions and influencing factors. In addition, the inevitable form II to form I spontaneous transition mechanism and the transformation kinetics is reviewed based on the existing research works, aiming for it to be useful for its processing in different phases and the further technical development of new methods for accelerating or even bypass its form II to form I transformation.

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“…It has been reported that the copolymerization of structural co-units to the polybutene-1 main chain may vary the crystallization polymorphism from the regular form (tetragonal form II) to the thermodynamically stable hexagonal form I’ [37,46]. It is also known that the former has a much faster growth rate than the latter [47]. Then, concerning the aforementioned increased T c in PEG-grafted copolymers, the modification of cooling-generated crystallites should be examined to know whether the contribution arises from the variation of crystallization polymorphism.…”

Section: Resultsmentioning

confidence: 99%

Thermal Analysis of Crystallization and Phase Transition in Novel Polyethylene Glycol Grafted Butene-1 Copolymers

Lou

et al. 2019

Polymers

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Copolymerization is an effective strategy to regulate the molecular structure and tune crystalline structures. In this work, novel butene-1 copolymers with different polyethylene glycol (PEG) grafts (number-average molecular weight Mn = 750, 2000, and 4000 g/mol) were synthesized, for the first time introducing long-chain grafts to the polybutene-1 main chain. For these PEG-grafted copolymers, crystallization, melting, and phase transition behaviors were explored using differential scanning calorimetry. With respect to the linear homopolymer, the incorporation of a trimethylsilyl group decreases the cooling crystallization temperature (Tc), whereas the presence of the long PEG grafts unexpectedly elevates Tc. For isothermal crystallization, a critical temperature was found at 70 °C, below which all polyethylene glycol-grafted butene-1 (PB-PEG) copolymers have faster crystallization kinetics than polybutene-1 (PB). The subsequent melting process shows that for the identical crystallization temperature, generated PB-PEG crystallites always have lower melting temperatures than that of PB. Moreover, the II-I phase transition behavior of copolymers is also dependent on the length of PEG grafts. When form II, obtained from isothermal crystallization at 60 °C, was annealed at 25 °C, PB-PEG-750, with the shortest PEG grafts of Mn = 750 g/mol, could have the faster transition rate than PB. However, PB-PEG-750 exhibits a negative correlation between transition rate and crystallization temperature. Differently, in PB-PEG copolymers with PEG grafts Mn = 2000 and 4000 g/mol, transition rates rise with elevating crystallization temperature, which is similar with homopolymer PB. Therefore, the grafting of the PEG side chain provides the available method to tune phase transition without sacrificing crystallization capability in butene-1 copolymers.

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Direct crystal growth of isotactic polybutene-1 trigonal phase in the melt: In-situ observation

Cited by 17 publications

References 23 publications

Real-Space in Situ Study of the II–I Phase Transition of Isotactic Poly(1-butene)

Real-Space in Situ Study of the II–I Phase Transition of Isotactic Poly(1-butene)

Polymorphic Behavior and Phase Transition of Poly(1-Butene) and Its Copolymers

Thermal Analysis of Crystallization and Phase Transition in Novel Polyethylene Glycol Grafted Butene-1 Copolymers

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