scholarly journals Investigation of the Ordered Structure in Partially Melted Isotactic Polypropylene

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3354
Author(s):  
Junfang Shen ◽  
Derong Zhu ◽  
Junchao An ◽  
Zhiyu Min ◽  
Jingbo Chen
Keyword(s):  
Isotactic Polypropylene ◽  
Crystallization Process ◽  
Scattering Amplitude ◽  
Wide Angle ◽  
Ordered Structure ◽  
Crystalline Morphology ◽  
X Ray ◽  
X Ray Scattering ◽  
Cylindrical Form ◽  
History Of

The ordered structure of partially melted isotactic polypropylene (iPP) was investigated using polarized optical microscopy (POM) and small-/wide-angle X-ray scattering (SAXS/WAXS) measurements. The crystalline morphology was first examined by means of pulling a glass fiber through the iPP melt, which was generated by partially melting a preformed spherulite. The results from the POM experiments indicated that, even at a minimal pulling rate, the surviving ordered structure could also relocate along the direction of fiber pulling and grow into cylindrites eventually. In addition, during the quiescent crystallization from the partially melted sample, which had the same thermal history of fiber-pulling experiments, the obvious memory effect of melt was also observed from the results of X-ray experiments. Moreover, the SAXS profile derived from the partially melted iPP at 170 °C was fitted by the theory of scattering amplitude with the cylindrical form factor. The fit result implied that the surviving ordered structure is of cylindrical nanocrystals with a diameter D ≈ 30 ± 3 nm and height h ≈ 45 ± 3 nm, which can significantly influence the crystallization morphology and kinetics during the subsequent crystallization process.

Microstructure characterization in a single isotactic polypropylene spherulite by synchrotron microfocus wide angle X-ray scattering

Polymer ◽  
2018 ◽  
Vol 142 ◽  
pp. 387-393 ◽  
Author(s):  
Baobao Chang ◽  
Konrad Schneider ◽  
Nilesh Patil ◽  
Stephan Roth ◽  
Gert Heinrich
Keyword(s):  
Isotactic Polypropylene ◽  
Microstructure Characterization ◽  
Wide Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Effect of Counterions on the Interaction among Concentrated Spherical Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1911
Author(s):  
Yunwei Wang ◽  
Li Li ◽  
Yiming Wang ◽  
Qingsong Yang ◽  
Zhishuang Ye ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Electrostatic Interaction ◽  
Wide Angle ◽  
Ordered Structure ◽  
X Ray ◽  
Polyelectrolyte Brushes ◽  
X Ray Scattering ◽  
Spherical Polyelectrolyte Brushes ◽  
Brush Layer ◽  
Ray Scattering

The effect of counterions on interactions among spherical polyelectrolyte brushes (SPBs) was systematically investigated by rheology, small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). The SPB particles consist of a solid polystyrene (PS) core with a diameter of ca.100 nm and a chemically grafted poly-(acrylic acid) (PAA) brush layer. Metal ions of different valences (Na+, Mg2+ and Al3+) were used as counterions to study the interactions among concentrated SPBs. The so-called “structure factor peak” in SAXS, the “local ordered structure peak” in WAXS and rheological properties indicated the interactions among concentrated SPBs. Combining SAXS, WAXS and rheology, the formation mechanism of the local ordered structure among PAA chains in the overlapped area of adjacent SPB, which was generated due to the bridge function of counterions, was confirmed. In contrast, excessive counterions shielded the electrostatic interaction among PAA chains and destroyed the local ordered structure. This work enriches our understanding of the polyelectrolyte assembly in concentrated SPBs under the effect of counterions and lays the foundations for SPB applications.

Mapping structural gradients in isotactic polypropylene using scanning wide-angle X-ray scattering

Polymer ◽  
2013 ◽  
Vol 54 (7) ◽  
pp. 1867-1875 ◽  
Author(s):  
Håvard Granlund ◽  
Jostein Bø Fløystad ◽  
Morteza Esmaeili ◽  
Eirik Torbjørn Bakken ◽  
Martin Bech ◽  
...  
Keyword(s):  
Isotactic Polypropylene ◽  
Wide Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

A time-resolved SAXS study on the crystalline morphology of long-term stored isotactic polypropylene

2004 ◽  
Vol 37 (2) ◽  
pp. 295-299 ◽  
Author(s):  
Jun-Ting Xu ◽  
Yu-Jin Zhang ◽  
Zhi-Qiang Fan
Keyword(s):  
Isotactic Polypropylene ◽  
Crystal Form ◽  
Crystalline Morphology ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Time Resolved ◽  
Crystal Forms ◽  
X Ray ◽  
X Ray Scattering

The crystalline morphology of a long-term stored metallocene isotactic polypropylene (mPP) has been studied with time-resolved small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), and compared with that of the freshly crystallized sample. It was found that both α and γ crystal forms occur in the long-term stored mPP, whereas freshly crystallized mPP contains only the α crystal form. Double SAXS peaks were observed for the long-term stored mPP, which can be assigned to the α and γ crystals. Based on the SAXS result, it is inferred that the crystal stacks of the α and γ forms in the long-term stored mPP are arranged according to the block mode.

In Situ X-Ray Characterization of Isotactic Polypropylene: Dependence of the Crystalline Properties on the Draw Down Ratio

2008 ◽  
Vol 587-588 ◽  
pp. 572-576
Author(s):  
Paulo E. Lopes ◽  
William T. Pennington ◽  
Michael S. Ellison
Keyword(s):  
Isotactic Polypropylene ◽  
Small Angle ◽  
Ex Situ ◽  
Wide Angle ◽  
Experimental Conditions ◽  
Crystalline Orientation ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Polymer crystalline regions can be characterized by wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). The in-situ study of isotactic polypropylene with measurement of wide angle and small angle X-ray scattering (WAXS and SAXS), at varying distances from the exit of the extruder have been successfully completed using an X-ray system with a standard X-ray source. The processing conditions, used were: 50, 100, 200 and 400m.min-1 for the take up speed, 0.3, 0.6, and 1.2 cm3min-1hole-1 for the melt flow rates, and a spinning temperature of 220°C. These experimental conditions produced draw down ratios ranging from 33 up to 1058. The X-ray characterization was carried in-situ at 15, 30, 45 and 60 cm from the exit of the spinneret and also ex-situ. The results obtained show the crystallinity index and the crystalline orientation to increase for the higher draw down rates, as expected under draw induced crystallization conditions, and a logarithmic relationship was observed within the experimental conditions used in this work. This communication reports the relationship between the crystallinity, crystalline orientation and lamellar long period and draw down ratio along the spin line.

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

Polymers ◽  
2018 ◽  
Vol 10 (2) ◽  
pp. 162 ◽  
Author(s):  
Finizia Auriemma ◽  
Claudio De Rosa ◽  
Rocco Di Girolamo ◽  
Anna Malafronte ◽  
Miriam Scoti ◽  
...  
Keyword(s):  
Isotactic Polypropylene ◽  
Wide Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Measurements ◽  
Ray Scattering
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