Polymorphism of isotactic polybutene-1 as revealed by microindentation hardness. Part II: correlations to microstructure

Azzurri, Fiorenza; Flores, A.; Alfonso, Giovanni Carlo; Šics, Igors; Hsiao, Benjamin S.; Calleja, F. J. Baltá

doi:10.1016/s0032-3861(02)00864-9

Cited by 88 publications

(69 citation statements)

References 18 publications

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“…The T m of this sample is 130 1C. At ambient temperature, the 13 C crystalline signals of form I are very sharp and dominate the spectrum. Very broad signals with At elevated temperature, the 13 C line widths of the crystalline signals are almost invariant.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 94%

“…To prevent thermal degradation, nitrogen gas was circulated around the sample pan. Figure 1 shows 13 C CPMAS NMR spectra of iPB1 crystallized at 100 1C, signal assignments and a DSC chart. The T m of this sample is 130 1C.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

“…At 128 ± 2 1C, the crystal is mostly melted and only small crystalline signals and further narrowed amorphous signals are observed. At 136 ± 2 1C, there is no 13 C CPMAS signal, indicating complete melting. Through this temperature dependence, 13 C line widths of all of the crystalline signals show no broadening up to T m .…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

“…These effects are caused neither by an increased crystallinity of the material, because the crystal fraction does not change during the transition, nor by variations of morphology. [11][12][13][14] Despite many structural investigations of the solid-solid transition of iPB1, [6][7][8][9][10][11][12][13][14] the origin of its outstanding mechanical properties is not fully understood.…”

Section: Introductionmentioning

confidence: 99%

“…Beckham et al 24 detected overall segmental motions in form II above T g ¼À23 1C. Maring et al 23 investigated molecular dynamics in form I using high-resolution 13 C NMR. They did not observe any evidence for molecular dynamics in form I in the mid 10 kHz range up to 90 1C.…”

Section: Introductionmentioning

confidence: 99%

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Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

Miyoshi

Mamun

2011

Polym J

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Isotactic-poly(1-butene) (iPB1) shows superior mechanical properties after crystal-crystal transitions. Recently, Miyoshi et al. found that crystalline stems in metastable tetragonal crystal perform uniaxial rotational diffusions accompanying side-chain conformational transitions in the fast motional limit (correlation time, /s c S o10 À7 s; Macromolecules 2010, 43, 3986-3989.). In this study, molecular dynamics in stable trigonal crystal is investigated by solid-state nuclear magnetic resonance, which indicates that crystalline stems and side-chain conformations are completely fixed up to melting points (/s c S 410 s). In addition, lamellar thickness, /lS of iPB1 and a low isotacticity iPB1 (low_iPB1) with /mmmmS¼78%, respectively, were investigated by small-angle X-ray scattering. The low_iPB1 sample shows very week supercooling dependence of /lS (B5 nm), whereas iPB1 shows strong supercooling dependence of /lS (10-28 nm). On the basis of molecular dynamics and /lS results, molecular dynamics effects on structures and unique mechanical property of iPB1 are discussed.

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Section: Differential Scanning Calorimetrymentioning

confidence: 94%

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

Miyoshi

Mamun

2011

Polym J

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Hardness

Calleja

Flores

2011

Encyclopedia of Polymer Science and Technology

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A description of the hardness technique and its application to polymer systems is presented. The method is based on the local deformation produced on a material surface by an indenter upon application of a given load. Conventional methods based on the optical measure of the residual impression left behind upon load release represent a rather simple technique for a rapid evaluation of the surface mechanical properties. In the past two decades, depth‐sensing indentation devices based on the monitoring of the load and displacement throughout an indentation have progressively substituted traditional testers. Smaller loads can be applied capable of producing penetration depths in the nanoscale. Indentation hardness has nowadays gained widespread application in polymer science. Besides its aforementioned technical advantages, one has to add its extreme sensitivity to detect nanostructural changes occurring in polymer materials. Behind this ability is the intimate correlation between the mechanisms of local deformation and the polymer basic nanostructural entities. The present contribution intends to provide the reader a general overview of the state of the art of indentation hardness in relation to nanostructure and morphology in glassy and semicrystalline polymers including blends.

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Effect of Pre‐Existed Form I' on the Phase Transition of Isotactic Poly‐1‐butene Form III under High Pressure CO₂

Liu

Zhao

2010

Macromolecular Symposia

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The CO2 plasticization effect on the isotactic poly‐1‐butene (iPB‐1) form III with pre‐existed minority form I' was investigated by using high‐pressure differential scanning calorimetry (DSC). The results showed that the form III melting peak moved to a lower temperature and the melting peak area of form II generated during heating decreased with the increased CO2 pressure. The solid‐solid transition of form III to I' in the iPB‐1 was mainly studied by fourier transform infrared spectroscopy (FTIR). It was claimed that the phase transition was a thermodynamic process and the pre‐existed form I' in form III inhibit the phase transition of form III into I'. The influence of the pre‐existed form I' on the melting behavior of the iPB‐1 was also studied by DSC. It was found that the form I' also suppressed the recrystallization of form II.

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Polymorphism of isotactic polybutene-1 as revealed by microindentation hardness. Part II: correlations to microstructure

Cited by 88 publications

References 18 publications

Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

Hardness

Effect of Pre‐Existed Form I' on the Phase Transition of Isotactic Poly‐1‐butene Form III under High Pressure CO₂

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Polymorphism of isotactic polybutene-1 as revealed by microindentation hardness. Part II: correlations to microstructure

Cited by 88 publications

References 18 publications

Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

Hardness

Effect of Pre‐Existed Form I' on the Phase Transition of Isotactic Poly‐1‐butene Form III under High Pressure CO2

Contact Info

Product

Resources

About

Effect of Pre‐Existed Form I' on the Phase Transition of Isotactic Poly‐1‐butene Form III under High Pressure CO₂