Influence of Draw Ratio on Crystal Morphology and Structure of β-Form of Isotactic Polypropylene

2011 ◽  
Vol 221 ◽  
pp. 54-59
Author(s):  
Bin Zhang ◽  
Jing Bo Chen ◽  
Bi Wei Qiu ◽  
Fang Fang Ji ◽  
Chang Yu Shen
Keyword(s):  
Draw Ratio ◽  
Crystal Morphology ◽  
Polarized Light ◽  
Content Increase ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Slit Die ◽  
Polymorphic Nature

The effects of the draw ratio (DR) on the polymorphic nature of β-iPP were investigated by polarized light microscopy (PLM), wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS) and differential scanning calorimeter (DSC). The iPP sheet is extruded through a slit die, and then the extruded sheets were hot stretched with the different draw ratio (DR). DSC and WAXD results indicate that the β-iPP content increase with DR increasing from 4.8 to 10.8. β-spherulites can be observed by PLM in the stretched specimen even at a lower DR (4.8). With increasing draw ratio, the relative amount of the β-cylindrites crystals gradually increased.

Time-resolved isothermal crystallization of absorbable PGA-co-PLA copolymer by synchrotron small-angle X-ray scattering and wide-angle X-ray diffraction

Polymer ◽  
2001 ◽  
Vol 42 (21) ◽  
pp. 8965-8973 ◽  
Author(s):  
Zhi-Gang Wang ◽  
Xuehui Wang ◽  
Benjamin S. Hsiao ◽  
Saša Andjelić ◽  
Dennis Jamiolkowski ◽  
...  
Keyword(s):  
Small Angle ◽  
Isothermal Crystallization ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Structure and properties of polypropylene/organic rectorite nanocomposites

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 35-50 ◽  
Author(s):  
Yun Huang ◽  
Xiaoyan Ma ◽  
Guozheng Liang ◽  
Hongxia Yan
Keyword(s):  
Loss Modulus ◽  
Polarized Light ◽  
Clay Content ◽  
Crystal Form ◽  
Ammonium Bromide ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Monoclinic Crystal ◽  
X Ray

AbstractMelt blending using a twin-screw extruder was used to prepare composites of polypropylene (PP)/organic rectorite (PR). The organic rectorite (OREC) was modified with dodecyl benzyl dimethyl ammonium bromide (1227). Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy were used to investigate the dispersion of OREC in the composites. The d spacings of OREC in PR composites was greater than in OREC itself. The dispersion of OREC particles in the PP polymer matrix was fine and uniform when the clay content was small (2 wt.%). The rheology was characterized using a capillary rheometer. The processing behaviour of the PR system improved as the amount of OREC added increased. Non-isothermal crystallization kinetics were analysed using differential scanning calorimetry. It was shown that the addition of OREC had a heterogeneous nucleation effect on PP, and can accelerate the crystallization. However, only when fine dispersion was achieved, and at lower rates of temperature decrease, was the crystallinity greater. Wide-angle X-ray diffraction and polarized light microscopy were used to observe the crystalline form and crystallite size. The PP in the PR composites exhibited an a-monoclinic crystal form, as in pure PP, and in both cases a spherulite structure was observed. However, the smaller spherulite size in the PR systems indicated that addition of OREC can reduce the crystal size significantly, which might improve the ‘toughness’ of the PP. The mechanical properties (tensile and impact strength) improved when the amount of OREC added was appropriate. Dynamic mechanical analysis showed that the storage modulus (E′) and loss modulus (E″) of the nanocomposites were somewhat greater than those of pure PP when an appropriate amount of OREC was added. Finally, thermogravimetric analysis showed that the PR systems exhibited a greater thermal stability than was seen with pure PP.

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

scholarly journals Fiber Formation during Melt Blowing

2003 ◽  
Vol os-12 (2) ◽  
pp. 1558925003os-12 ◽  
Author(s):  
Randall R. Bresee ◽  
Wen-Chien Ko
Keyword(s):  
Fiber Diameter ◽  
Fiber Formation ◽  
Experimental Measurements ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Air Velocity ◽  
Melt Blowing ◽  
X Ray ◽  
X Ray Scattering ◽  
Insight Into

Experimental measurements are presented to provide phenomenological insight into the commercial melt blowing process. In particular, we discuss the following experimental measurements obtained at various die-collector locations: fiber diameter, fiber velocity, air velocity, fiber acceleration, fiber entanglement, fiber temperature, birefringence, wide-angle x-ray diffraction and small-angle x-ray scattering. Our discussion focuses on how these measurements provide insight into fiber formation during melt blowing.

scholarly journals Influence of Molecular Orientation on the Melting Behavior of Poly(phenylene sulfide) Fibers

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800
Author(s):  
Prabhakar Gulgunje ◽  
Gajanan Bhat ◽  
Joseph Spruiell
Keyword(s):  
Differential Scanning Calorimetry ◽  
Molecular Orientation ◽  
Polarized Light ◽  
Melting Behavior ◽  
Probable Mechanism ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Phenylene Sulfide

The influence of molecular orientation on the melting behavior of draw-annealed poly(phenylene sulfide) fibers is investigated in the present paper. Tools used to probe the investigation were differential scanning calorimetry, polarized light optical microscopy, wide angle X-ray diffraction, and small angle X-ray diffraction. It is shown that molecular orientation in the crystalline and amorphous regions play a key role in crystal rearrangement during melting. A probable mechanism by which amorphous orientation influences crystal rearrangement is also discussed.

Self-organized structures of hydrogen bonded poly(4-vinylphenol) - tertiary amino lipid mixtures

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Isamu Akiba ◽  
Kazuo Sakurai
Keyword(s):  
Ir Spectroscopy ◽  
Small Angle ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lamellar Structures ◽  
Self Organized ◽  
X Ray Scattering ◽  
Lipid Mixtures ◽  
Tertiary Amino

AbstractMesomorphic structures of hydrogen bridged poly(4-vinylphenol) - N,N-dimethyl- n-octadecylamine (PVPh-NDOA) and PVPh - N,N-dioctadecylmethylamine (PVPh-DOMA) mixtures were investigated by means of wide angle X-ray diffraction, small angle X-ray scattering, and IR spectroscopy. Octadecyl chains of the PVPh-NDOA and PVPh-DOMA mixtures showed hexagonal αH and orthorhombic βO packing, respectively. In addition, PVPh-NDOA and PVPh-DOMA formed lamellar structures with periods of 3.5 and 2.5 nm, respectively.

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