Stretching behavior of the butene‐1/ethylene random copolymer: A direct correspondence between triggering of II‐I phase transition and mechanical yielding

Wang, Wei; Zheng, Lirong; Liu, Liyuan; Li, Wei; Li, Yuesheng; Ma, Zhe

doi:10.1002/pcr2.10052

Cited by 11 publications

(12 citation statements)

References 79 publications

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“…Copolymerization with secondary co-units at a low concentration is a robust strategy for tuning the molecular architecture and consequently the crystallization regime of a polymer, which determines the final properties of the material. − Thanks to the recent developments in organometallic catalysis, − varying the type and content of the extra co-units within a polymer chain has become much easier, even with polyolefins. The incorporated co-units can disturb the continuity of the bound repeating units and shorten the average length of the regular sequences, decreasing the crystallization kinetics. − On the other hand, other crystallization behaviors, such as polymorphism and phase stability, may be dramatically influenced by the co-unit. ,,− However, the current understanding of the relationship between the co-unit and the crystallization behavior of macromolecules is quite limited because of the limited number of available copolymers, but understanding these phenomena is crucial for developing novel materials.…”

Section: Introductionmentioning

confidence: 99%

Influence of Steric Norbornene Co-units on the Crystallization and Memory Effect of Polybutene-1 Copolymers

Liao

Liu

et al. 2020

Macromolecules

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The incorporation of the secondary co-units may not only change the kinetics and polymorphism of crystallization but also affect the melting behavior of polymers, leading to the memory effect even above the equilibrium melting temperature. In this work, a series of butene-1/norbornene random copolymers with 0−4.57 mol % steric norbornene (NBE) co-units was synthesized using rac-ethyl(1-indenyl) 2 zirconium dichloride as the catalyst. The melt crystallization, solid-phase transition, and memory effect associated with incomplete melting were studied with differential scanning calorimetry and in situ wide-angle Xray diffraction. The results show that unlike the polybutene-1 homopolymer, which always generates tetragonal crystals, the presence of steric NBE co-units can cause the copolymers to crystallize into trigonal form I′. The correlations of crystallization polymorphism with the NBE concentration and temperature were quantitatively established. For copolymer NBE2.36, the threshold temperature for generating pure form I′ crystals is 70 °C, and this decreases to 55 °C when the NBE concentration is increased to 4.57%. Moreover, for crystallized tetragonal form II, its spontaneous phase transition into thermodynamically more stable form I was significantly accelerated. On the other hand, the melting behaviors of the copolymers were influenced by the incorporation of NBE co-units, leading to the appearance of a memory effect. Interestingly, the memory effect not only accelerates the crystallization kinetics but also alters the crystallization polymorphism; the formation of form I′ was enhanced relative to form II. At a melt temperature of 120 °C, the initial form II crystallites dominate the memory effects because of their large lamellar thickness, while at a higher melt temperature (140 °C), form I′ is dominant due to its high thermal stability.

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Section: Introductionmentioning

confidence: 99%

Influence of Steric Norbornene Co-units on the Crystallization and Memory Effect of Polybutene-1 Copolymers

Liao

Liu

et al. 2020

Macromolecules

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“…Finally, PB-1 is a polymorphic polymer, which has diversified crystalline modifications, Forms I/I′, II, and III. , In practice, Forms I and II are the most processing-relevant modifications. Form II can be generated directly from regular melt crystallization as it is kinetically favored. − Form I is the most stable modification from a thermodynamic point of view, which is generally transformed from Form II through quiescent aging at room temperature. − Therefore, it arouses our interest to design a fibrous Form I substrate with a higher melting temperature to tailor the crystallization and morphology of Form II for high-performance all-PB-1 composites.…”

Section: Introductionmentioning

confidence: 99%

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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“…In addition to the physical approaches, such as the mechanical stretching and the supercritical fluid, the copolymerization of extra co‐units has shown the high capability to effectively tune the formation and evolution of crystallites. [ 17‐23 ]…”

Section: Background and Originality Contentmentioning

confidence: 99%

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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Stretching behavior of the butene‐1/ethylene random copolymer: A direct correspondence between triggering of II‐I phase transition and mechanical yielding

Cited by 11 publications

References 79 publications

Influence of Steric Norbornene Co-units on the Crystallization and Memory Effect of Polybutene-1 Copolymers

Influence of Steric Norbornene Co-units on the Crystallization and Memory Effect of Polybutene-1 Copolymers

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

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

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