Relationship Between Molecular Configuration and Stress-Induced Phase Transitions

Auriemma, Finizia; Rosa, Claudio De; Girolamo, Rocco Di; Malafronte, Anna; Scoti, Miriam; Mitchell, Geoffrey R.; Esposito, Serena

doi:10.1007/978-3-319-39322-3_11

Cited by 16 publications

(55 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The structural and morphological transformations of isotactic polypropylene (iPP) by effect of stretching have been widely studied [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. These studies are mainly concerned with iPP samples synthesized by Ziegler-Natta (ZN) heterogeneous catalyst systems [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

“…More recently, the deformation behavior of metallocene-made iPP samples with a uniform distribution of stereodefects has been also studied [ 16 , 17 , 18 , 19 , 20 ]. These samples contain only one kind of stereo-defects, namely isolated rr triads, at concentrations in the range 0.5–11 mol % [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

“…The study of the structural and morphological transitions occurring by effect of stretching in metallocene-made iPP samples was studied both at unit cell and lamellar length scales, by performing wide (WAXS) and small (SAXS) angle X-ray scattering measurements [ 16 , 17 , 18 , 19 , 20 ]. In particular, WAXS analysis show that during the transformation of the initially isotropic spherulitic morphology into a well oriented fiber morphology by effect of stretching, the initial crystalline α and/or γ forms transform into a well-oriented mesophase [ 16 , 17 , 18 , 19 , 20 ], as in Ziegler-Natta iPP [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The transformation into mesophase is gradual and starts occurring at deformations higher than the yielding point, that is concomitant with lamellar fragmentation (mechanical melting) and successive recrystallization into fibrils [ 17 , 18 , 19 , 20 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Time-Resolving Study of Stress-Induced Transformations of Isotactic Polypropylene through Wide Angle X-ray Scattering Measurements

Auriemma¹,

Rosa²,

Girolamo³

et al. 2018

Polymers

Self Cite

View full text Add to dashboard Cite

Abstract:The development of a highly oriented fiber morphology by effect of tensile deformation of stereodefective isotactic polypropylene (iPP) samples, starting from the unoriented γ form, is studied by following the transformation in real time during stretching through wide angle X-ray scattering (WAXS) measurements. In the stretching process, after yielding, the initial γ form transforms into the mesomorphic form of iPP through mechanical melting and re-crystallization. The analysis of the scattering invariant measured in the WAXS region highlights that the size of the mesomorphic domains included in the well oriented fiber morphology obtained at high deformations increases through a process which involves the coalescence of the small fragments formed by effect of tensile stress during lamellar destruction with the domain of higher dimensions.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Time-Resolving Study of Stress-Induced Transformations of Isotactic Polypropylene through Wide Angle X-ray Scattering Measurements

Auriemma¹,

Rosa²,

Girolamo³

et al. 2018

Polymers

Self Cite

View full text Add to dashboard Cite

show abstract

“…Crystalline polymer materials have been extensively used in packing, electronics, and industries, benefiting from their excellent mechanical properties . Those crystalline polymer materials are composed of crystalline and amorphous regions, and the crystalline region plays a key role in defining the mechanical strength and toughness during force‐induced melting . Therefore, understanding the molecular behavior and influencing factors in the force‐induced melting is of fundamental importance to design high‐performance polymer materials .…”

Section: Introductionmentioning

confidence: 99%

Force‐induced melting of a single polyethylene oxide chain from single crystal: Molecular behavior and influencing factors

Song

Yang

Jiang

et al. 2019

Polymer Crystallization

View full text Add to dashboard Cite

Force‐induced melting plays a key role in defining the mechanical strength and toughness of semicrystalline polymer materials. To understand its molecular mechanism, the direct measurement and monitoring of force‐induced melting process at the single‐molecule level are necessary. Here, the force‐induced melting of a single polyethylene oxide (PEO) chain from the single crystal has been investigated by using atomic force microscopy‐based single‐molecule force spectroscopy. Both the constant‐speed and constant‐force experiments show that PEO folds are unfolded predominantly one by one during the force‐induced melting process. The mechanical stability of PEO fold is confirmed to increase significantly with the increasing interfacial tension of polymer solvent and the thickness of crystal. The results obtained here provide new concepts in tuning the nanomechanical properties of crystalline polymer materials.

show abstract

“…The physical and mechanical properties of polymers depend on the molecular architecture, molar mass (M), size, and distributions [ 5 ]. The two fundamental properties, the size and M of polymers, can be experimentally determined in a number of ways.…”

Section: Introductionmentioning

confidence: 99%

Application of asymmetric flow field-flow fractionation (AF4) and multiangle light scattering (MALS) for the evaluation of changes in the product molar mass during PVP-b-PAMPS synthesis

et al. 2018

View full text Add to dashboard Cite

The use of polymers for the delivery of drugs has increased dramatically in the last decade. To ensure the desired properties and functionality of such substances, adequate characterization in terms of the molar mass (M) and size is essential. The aim of this study was to evaluate the changes in the M and size of PVP-b-PAMPS when the amounts of the synthesis reactants in the two-step radical reaction were varied. The determination of the M and size distributions was performed by an asymmetric flow field-flow fractionation (AF4) system connected to multiangle light scattering (MALS) and differential refractive index (dRI) detectors. The results show that the M of the polymers varies depending on the relative amounts of the reactants and that AF4-MALS-dRI is a powerful characterization technique for analyzing polymers. Using AF4, it was possible to separate the product of the first radical reaction (PVP-CTA) into two populations. The first population had an elongated, rod-like or random coil conformation, and the second had a conformation corresponding to homogeneous spheres or a microgel structure. PVP-b-PAMPS had only one population, which had a rod-like conformation. The molar masses of PVP-CTA and PVP-b-PAMPS found in this study were higher than those reported in previous studies.

show abstract

Relationship Between Molecular Configuration and Stress-Induced Phase Transitions

Cited by 16 publications

References 84 publications

Time-Resolving Study of Stress-Induced Transformations of Isotactic Polypropylene through Wide Angle X-ray Scattering Measurements

Time-Resolving Study of Stress-Induced Transformations of Isotactic Polypropylene through Wide Angle X-ray Scattering Measurements

Force‐induced melting of a single polyethylene oxide chain from single crystal: Molecular behavior and influencing factors

Application of asymmetric flow field-flow fractionation (AF4) and multiangle light scattering (MALS) for the evaluation of changes in the product molar mass during PVP-b-PAMPS synthesis

Contact Info

Product

Resources

About