Effect of pressure on the melting and crystallization behaviour of isotactic polybutene-1

Nakafuku, Chitoshi; Miyaki, Tsuyoshi

doi:10.1016/0032-3861(83)90124-6

Cited by 155 publications

(129 citation statements)

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“…The electron diffraction pattern shows a net pattern with hexagonal symmetry, and all the Bragg reflections could be indexed with the trigonal form of it-PB1. The melting temperature of the flat-on trigonal crystals observed by OM is around 124 C, which is much higher than the melting point of form I 0 , 96 C, and is rather close to that of form I reported by Nakafuku et al, 130 C. 7 OM and TEM observations indicate that the hexagonally shaped crystals are characterized as form I trigonal crystals grown in the melt.…”

Section: Resultsmentioning

confidence: 77%

“…Form I and form I 0 show the same X-ray and electron diffraction patterns, but have different melting temperatures (130 vs. 96 C). 7 Despite its excellent mechanical properties, the applications of it-PB1 has been limited considerably by the spontaneous tetragonal-trigonal solid state transformation. The transformation corresponds to a densification and shrinkage of crystals and brings about severe deformation of molded objects.…”

mentioning

confidence: 99%

“…1,2 Three different polymorphs, designated trigonal (forms I and I 0 ) and tetragonal (form II) and orthorhombic phases, have been reported in the literature. [3][4][5][6][7] Crystallization in the bulk melt under atmospheric pressure yields the tetragonal phase with 11/3 helical chains. 3,4 The tetragonal phase is unstable.…”

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confidence: 99%

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Melt Crystallization of isotactic Polybutene-1Trigonal Form: the Effect of Side Chain Entropy on Crystal Growth Kinetics

Yamashita

Takahashi

2008

Polym J

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The morphology and crystal growth kinetics of isotactic polybutene-1 (it-PB1) trigonal phase in molten thin films have been studied with transmission electron microscopy, electron diffraction and optical microscopy. The growth rate of trigonal crystals was determined by in situ optical microscopy. It is one hundredth that of it-PB1 tetragonal crystals. The growth rate of trigonal crystals, as well as that of tetragonal crystals, shows the supercooling dependence derived from the nucleation theory. Trigonal crystals grown at 75 and 90.1 C possessed well facetted morphology, which suggests the existence of flat growth faces required for nucleation theory between 75 and 90.1 C. This is consistent with the observed temperature dependence of trigonal crystal growth rate in accordance with the nucleation theory. Lateral surface free energy of the trigonal phase determined from the observed growth kinetics is about 7 times as large as the value Hoff calculated according to Hoffman's equation, while that of the tetragonal phase is roughly in agreement with the estimation. The discrepancy between the values of andHoff for the trigonal phase can be attributed to the loss of conformational entropy of the ethyl side chains of it-PB1.KEY WORDS: Isotactic Polybutene-1 / Trigonal Phase / Melt Crystallization / Growth Rate / Self-seeding / Surface Free Energy / Isotactic polybutene-1 (it-PB1) is a semicrystalline polyolefin which exhibits outstanding mechanical properties and pronounced polymorphs that depend on its crystallization conditions.

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Section: Resultsmentioning

confidence: 77%

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confidence: 99%

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Melt Crystallization of isotactic Polybutene-1Trigonal Form: the Effect of Side Chain Entropy on Crystal Growth Kinetics

Yamashita

Takahashi

2008

Polym J

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“…The different path of formation of form I and I 0 crystals yields differences regarding the crystal perfection, and, consequently, the less perfect modification I 0 exhibits a lower temperature of melting. 7,10,14 Form II and II 0 , similarly, have identical crystal structures, with the prime, in case of form II 0 , pointing to formation of crystals from the melt at elevated pressure, leading again to less perfect crystals with a lower temperature of melting than form II crystals. 14 The unit cell of forms II and II 0 is tetragonal, and the conformation of the molecules is characterized by a 11 3 helix.…”

Section: Introductionmentioning

confidence: 88%

“…11,12 In the presence of special nucleating agents, melt-crystallization can also lead to form III crystals. 8,9 Furthermore, melt-crystallization at elevated pressure higher than about 100 MPa, 7,10 on defined substrates 9 or of a strained melt results in formation of form I 0 crystals. Finally, crystallization during polymerization causes formation of form I 0 and form III crystals.…”

Section: Introductionmentioning

confidence: 99%

Effect of polymorphism of isotactic polybutene‐1 on peel behavior of polyethylene/polybutene‐1 peel systems

Nase

Androsch

Langer³

et al. 2007

J of Applied Polymer Sci

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The effect of polymorphism of isotactic polybutene-1 (iPB-1) on the peel behavior of the specific peel system low-density polyethylene/polybutene-1 (LDPE/iPB-1) was investigated using wide-angle X-ray scattering, calorimetry, and the T-peel test. Melt-crystallization of iPB-1, initially, yields tetragonal form II crystals which transform as a function of time to trigonal form I crystals. The kinetics of transformation at ambient temperature follows an exponential function, and is completed after about 50-75 h. The presence of LDPE in the peel system does not affect the transformation kinetics. The structure of the crystalline phase of iPB-1 controls the peel force which decreases by about 25% during the crystal-crystal transformation in a blend with 20 m% iPB-1. The reduction of the peel force depends linearly on the mass fraction of iPB-1 crystals in the peel system which further evidences the correlation between the crystalcrystal transformation of iPB-1 and the peel-characteristics of LDPE/iPB-1 blends. Isothermal reorganization of crystals of LDPE is excluded as reason for the change of the peel-performance of LDPE/iPB-1 blends, since it is 5 to 10 times faster than the decrease of the peel force, and crystal-crystal transformation of iPB-1, respectively.

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Polymers of Higher Olefins

Kissin¹

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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The article describes polymeric materials derived from the higher α‐olefins with carbon atom numbers of four or higher as well as polymers of cycloolefins. Crystalline polymers of higher α‐olefins belong to two classes of stereoregular polymers, isotactic and syndiotactic. Isotactic polymers are produced with two types of catalysts, heterogeneous Ziegler‐Natta catalysts and bridged metallocene catalysts. Other metallocene catalysts produce either crystalline syndiotactic polymers or amorphous atactic polymers. Higher α‐olefins can also be polymerized with cationic initiators to amorphous oligomeric materials. Cycloolefins are polymerized by two different mechanisms: the ring‐opening metathesis reaction catalyzed by tungsten or molybdenum compounds, and polymerization reactions without ring opening catalyzed by metallocenes. Two isotactic polymers of higher α‐olefins, poly(1‐butene) and poly(4‐methyl‐1‐pentene), as well as oligomers of linear α‐olefins and polymers of certain cycloolefins (polydicyclopentadiene, polyoctenamers, and norbornene elastomers) are produced commercially. Crystalline poly(1‐butene) is used to manufacture pipe, tubing, and blown film. Crystalline poly(4‐methyl‐1‐pentene) is a highly transparent plastic used for the manufacture of medical and chemical laboratory equipment as well as a variety of injection‐molded articles. Liquid oligomers of higher linear α‐olefins produced with cationic initiators have found wide applications as base oils in the formulation of various industrial lubricants; among other applications, they are used in synthetic lubricating oils for cars, transformer oils, and transmission and crankcase fluids. Polymers of cyclooctene are mostly used as components in rubber and compositions based on PVC or polystyrene. Cured liquid‐molding resins based on polydicyclopentadiene are used for the manufacture of automotive parts for trucks, snowmobiles, wheel loaders, and recreational vehicles.

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Effect of pressure on the melting and crystallization behaviour of isotactic polybutene-1

Cited by 155 publications

References 13 publications

Melt Crystallization of isotactic Polybutene-1Trigonal Form: the Effect of Side Chain Entropy on Crystal Growth Kinetics

Melt Crystallization of isotactic Polybutene-1Trigonal Form: the Effect of Side Chain Entropy on Crystal Growth Kinetics

Effect of polymorphism of isotactic polybutene‐1 on peel behavior of polyethylene/polybutene‐1 peel systems

Polymers of Higher Olefins

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