scholarly journals Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 618 ◽  
Author(s):  
Huajian Ji ◽  
Xulin Zhou ◽  
Xin Chen ◽  
Haili Zhao ◽  
Yu Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Yield Point ◽  
Isotactic Polypropylene ◽  
Microstructure Evolution ◽  
Crystal Size ◽  
Crystal Morphology ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

The microstructure evolution of an isotactic polypropylene (iPP) sheet during solid-state stretching was studied. The transition of the spherulites—cylindrites was evaluated using in-situ two-dimensional wide-angle and small-angle X-ray scattering methods. The crystallinity of stretched iPP sheets was characterized by differential scanning calorimetry. The crystal morphology was observed by means of scanning electron microscopy. It was found that the differences of crystal microstructure of the iPP sheet depended on the stretching strain, which promoted the orientation of molecular chains. Amorphous molecular chains in the spherulites oriented and formed into a mesophase near the yield point, and the partially ordered mesophase was further stretched to form an oriented cylindrite structure after the yield point. The highest relative content of cylindrites appeared at 15% strain. Notably, as the amorphous phase embedded into the lamellae layer, the crystal size decreased with the increase of strain, which indicated that the crystallinity of the stretched iPP sheet was much higher than that of unstretched iPP sheet. The induced cylindrites structure played a more important role in improving the mechanical properties and heat resistance of iPP sheets. Compared with the unstretched iPP sheets, the tensile strength increased by 28%, the notch impact toughness significantly increased by 78%, and the vicat softening point increased from 104 to 112 °C.

scholarly journals Microstructure evolution during the isostructural decomposition of TiAlN—A combined in-situ small angle x-ray scattering and phase field study

2013 ◽  
Vol 113 (21) ◽  
pp. 213518 ◽  
Author(s):  
A. Knutsson ◽  
J. Ullbrand ◽  
L. Rogström ◽  
N. Norrby ◽  
L. J. S. Johnson ◽  
...  
Keyword(s):  
Field Study ◽  
Microstructure Evolution ◽  
Phase Field ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals In Situ Time-Resolved X-ray Scattering Study of Isotactic Polypropylene in Additive Manufacturing

2019 ◽  
Vol 11 (40) ◽  
pp. 37112-37120 ◽  
Author(s):  
Yuval Shmueli ◽  
Yu-Chung Lin ◽  
Sungsik Lee ◽  
Mikhail Zhernenkov ◽  
Rina Tannenbaum ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Isotactic Polypropylene ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

In Situ High Temperature X-Ray Diffraction Studies of Modified Poly(Ethylene Terephthalate)

1992 ◽  
Vol 36 ◽  
pp. 379-386
Author(s):  
T. Blanton ◽  
R. Seyler
Keyword(s):  
High Temperature ◽  
Ethylene Terephthalate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Pet Crystallization

The effect of dimethyl-5-sodiosulfoisophthalate, SIP, on poly(ethylene terephthalate), PET, crystallization has been studied using in situ high-temperature x-ray diffraction, HTXRD. At low levels of SIP modification, PET-like crystallinity was observed. At high SIP levels, clustering of polyester ionomers was observed and crystallization was significantly suppressed. The HTXRD data along with differential scanning calorimetry, DSC, and small angle x-ray scattering, SAXS, indicate that the change from bulk crystallization to bulk ionomer formation occurred when 8-12 mol% of the diester linkages contained SIP.

Tautomeric polymorphism of the neuroactive inhibitor kynurenic acid

2019 ◽  
Vol 75 (6) ◽  
pp. 793-805
Author(s):  
Dorota Pogoda ◽  
Jan Janczak ◽  
Sylwia Pawlak ◽  
Michael Zaworotko ◽  
Veneta Videnova-Adrabinska
Keyword(s):  
Solid State ◽  
Kynurenic Acid ◽  
Variable Temperature ◽  
Neurological Diseases ◽  
Crystal Form ◽  
Phase Behaviour ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Kynurenic acid (KYN; systematic name: 4-hydroxyquinoline-2-carboxylic acid, C10H7NO3) displays a therapeutic effect in the treatment of some neurological diseases and is used as a broad-spectrum neuroprotective agent. However, it is understudied with respect to its solid-state chemistry and only one crystal form (α-KYN·H2O) has been reported up to now. Therefore, an attempt to synthesize alternative solid-state forms of KYN was undertaken and six new species were obtained: five solvates and one salt. One of them is a new polymorph, β-KYN·H2O, of the already known KYN monohydrate. All crystal species were further studied by single-crystal and powder X-ray diffraction, thermal and spectroscopic methods. In addition to the above methods, differential scanning calorimetry (DSC), in-situ variable-temperature powder X-ray diffraction and Raman microscopy were applied to characterize the phase behaviour of the new forms. All the compounds display a zwitterionic form of KYN and two different enol–keto tautomers are observed depending on the crystallization solvent used.

Diffusion-Controlled Nanocrystallization of the Fe73.5Cu1Nb3Si15.5B7 Finemet Amorphous Alloy

2008 ◽  
Vol 570 ◽  
pp. 120-125
Author(s):  
R.M. Ribeiro ◽  
R.S. de Biasi ◽  
D.R. dos Santos ◽  
Dílson S. dos Santos
Keyword(s):  
Differential Scanning Calorimetry ◽  
Amorphous Alloy ◽  
Small Angle ◽  
Nucleation And Growth ◽  
Amorphous Metallic Alloy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Diffusion Controlled

Crystallization of the amorphous metallic alloy Fe73.5 Cu1Nb3 Si8.5 B14 was investigated by ferromagnetic resonance (FMR), small angle in situ X-ray scattering (SAXS/WAXS) and differential scanning calorimetry (DSC). Only one crystalline phase was observed by WAXS and only one peak was observed by DSC. The activation energies, calculated from FMR and DSC data, were 287 kJ.mol-1 and 313.4 kJ.mol-1, respectively. The values calculated for the Avrami exponent were 0.98 (FMR) and 1.4 (DSC). These values correspond to different mechanisms of nucleation and growth; however, the SAXS /WAXS results suggest that the dominant mechanisms are nucleation and growth of crystals from small dimensions.

In Situ Synchrotron X-ray Scattering Study on Isotactic Polypropylene Crystallization under the Coexistence of Shear Flow and Carbon Nanotubes

2011 ◽  
Vol 44 (20) ◽  
pp. 8080-8092 ◽  
Author(s):  
Yan-Hui Chen ◽  
Gan-Ji Zhong ◽  
Jun Lei ◽  
Zhong-Ming Li ◽  
Benjamin S. Hsiao
Keyword(s):  
Carbon Nanotubes ◽  
Shear Flow ◽  
Isotactic Polypropylene ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

A small/wide-angle X-ray scattering instrument for structural characterization of air–liquid interfaces, thin films and bulk specimens

2009 ◽  
Vol 43 (1) ◽  
pp. 110-121 ◽  
Author(s):  
U-Ser Jeng ◽  
Chiu Hun Su ◽  
Chun-Jen Su ◽  
Kuei-Fen Liao ◽  
Wei-Tsung Chuang ◽  
...  
Keyword(s):  
Thin Films ◽  
Lipid Vesicles ◽  
Wide Angle ◽  
Liquid Interfaces ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Gas Detectors ◽  
X Ray Scattering ◽  
Ray Scattering

At the National Synchrotron Radiation Research Center, a small/wide-angle X-ray scattering (SAXS/WAXS) instrument has been installed at the BL23A beamline with a superconducting wiggler insertion device. This beamline is equipped with double Si(111) crystal and double Mo/B4C multilayer monochromators, and an Si-based plane mirror that can selectively deflect the beam downwards for grazing-incidence SAXS (GISAXS) studies of air–liquid or liquid–liquid interfaces. The SAXS/WAXS instrument, situated in an experimental hutch, comprises collimation, sample and post-sample stages. Pinholes and slits have been incorporated into the beam collimation system spanning a distance of ∼5 m. The sample stage can accommodate various sample geometries for air–liquid interfaces, thin films, and solution and solid samples. The post-sample section consists of a 1 m WAXS section with two linear gas detectors, a vacuum bellows (1–4 m), a two-beamstop system and the SAXS detector system, all situated on a motorized optical bench for motion in six degrees of freedom. In particular, the vacuum bellows of a large inner diameter (260 mm) provides continuous changes of the sample-to-detector distance under vacuum. Synchronized SAXS and WAXS measurements are realizedviaa data-acquisition protocol that can integrate the two linear gas detectors for WAXS and the area detector for SAXS (gas type or Mar165 CCD); the protocol also incorporates sample changing and temperature control for programmable data collection. The performance of the instrument is illustratedviaseveral different measurements, including (1) simultaneous SAXS/WAXS and differential scanning calorimetry for polymer crystallization, (2) structural evolution with a large ordering spacing of ∼250 nm in a supramolecular complex, (3) SAXS for polymer blends underin situdrawing, (4) SAXS and anomalous SAXS for unilamellar lipid vesicles and metalloprotein solutions, (5) anomalous GISAXS for oriented membranes of Br-labeled lipids embedded with peptides, and (6) GISAXS for silicate films formedin situat the air–water interface.

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