Characteristics of several kinds of polyethylene gel estimated by small‐angle light scattering under cross polarization

Luo, Yan‐Ling; Kayakabe, Seiko; Xiang, Ying; Bin, Yuezhen; Xu, Chunye; Matsuo, Masaru

doi:10.1002/polb.22166

Cited by 5 publications

(4 citation statements)

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“…Nevertheless, it cannot be excluded that some degree of liquid−liquid phase separation could occur during the dynamic gelation process upon quenching the UHMWPE solutions to room temperature. 44,45 Gel State. The second step in the gel-spinning process involves crystallization of the UHMWPE in solution leading to gelation.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Influence of Solvent Quality and Crystallization Conditions on the Drawability of Ultra-High Molecular Weight Polyethylene Cast from Solution

2020

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The standard route toward high-performance polyethylene fibers involves “ultra-drawing”: large-strain solid-state uniaxial plastic deformation at elevated temperatures of precursor ultra-high molecular weight polyethylene (UHMWPE) fibers to achieve crucial near-to-perfect orientation of macromolecular chains. It is well accepted that the drawability (and therewith orientation) of UHMWPE is largely determined by the entanglement density. This research evaluates the effect of solvent quality and crystallization conditions on ultra-drawability of UHMWPE by several independent experimental methods. Rheological and mechanical evaluation of the elastic properties of UHMWPE solutions and the resulting gels cast from good and poor solvents show that at a given UHMWPE concentration, the entanglement density in solution and the connectivity in the resulting gels are similar if not identical, suggesting that the entanglement density is not directly influenced by solvent quality. Nevertheless, at a given concentration, dried films obtained from poor solvents depict a twofold higher drawability, resulting in improved fiber properties. The observed correlation of the maximum draw ratio with lamellar thickness of films cast from poor and good solvents at a given polymer concentration suggests that polymer crystals formed at low undercooling have a higher maximum draw ratio. In addition, this study presents two new methods that, by solely changing the crystallization conditions of UHMWPE solutions at a given polymer concentration, result in an increase in the maximum draw ratio of the produced UHMWPE precursor films and ultimately leading to improved fiber properties.

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Section: ■ Results and Discussionmentioning

confidence: 99%

“…These findings apply, especially for the poor solvents, to all solutions studied up to concentrations of UHMWPE of 30 vol %. Nevertheless, it cannot be excluded that some degree of liquid–liquid phase separation could occur during the dynamic gelation process upon quenching the UHMWPE solutions to room temperature. , …”

Section: Resultsmentioning

confidence: 99%

Influence of Solvent Quality and Crystallization Conditions on the Drawability of Ultra-High Molecular Weight Polyethylene Cast from Solution

2020

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“…Of course, the concept shown in Figure was applied to the systems concerning spherulite and rod . The theoretical patterns were in good agreement with the observed patterns.…”

Section: Small Angle Light Scattering (Saxs) Under Polarization Discumentioning

confidence: 99%

Understandable Unified Description about Diffraction and Scattering of X‐Ray and Visible Light Beams from Soft Matters in Terms of Educational Aspects

Matsuo

Bin

Zhou

2018

Macromolecular Symposia

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In attempt to pursue easy understanding about 1) wide angle X‐ray diffraction (WAXD), 2) small angle X‐ray scattering (SAXS) and 3) small angle light scattering (SALS) under polarization, teaching methods in this manuscript are focused on the concept that quantitative analysis above three phenomena are developed from a unified fundamental equation EE* (E: scattering amplitude, E*: the conjugate complex). The graduate students studying material science can understand the approach based on mathematical knowledge within undergraduate educational curriculum. This approach refers to two important points associated with the different developments. The first is the different wave lengths between X‐ray and visible light associated with different photon energy. When an incident X‐ray beam is entered in the polymer material, electrons in atoms behave as free electrons because of high photon energy. On the other hand, when visible light with low photon energy is entered, electrons of atom cause vibration on bottom of the potential box. These different electron behaviors emphasize to provide the different scattering modes of X‐ray and visible light. The second is the commentary about branching point about the mathematical treatments concerning X‐ray diffraction and scattering amplitude in spite of a unified equation represented by Equation (II‐1). This is explained in terms of focusing element scales. The diffraction and scattering in most of the textbooks have been written individually by different authors and then the descriptions have been never focused on the branching point.

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“…33,34 Such a phenomenon could also be accompanied by crystallization in the case of semicrystalline polymers. 26 Gels with crystallizable polymers such as isotactic polystyrene, poly(vinyl chloride), and polyethylene have been studied, [35][36][37][38][39][40][41] and liquid-liquid phase separation accompanied by crystallization has been attributed to the formation of networks.…”

Section: Supramolecular Gels Vs Polymer Gelsmentioning

confidence: 99%

Self-Sorting Sergeant-Soldier, and Majority Rules Phenomena in Crystals and Gels of Polyurethane Model Compounds

Chan¹

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Hydrogen bond-mediated self-assembling biscarbamates have been studied by our group as model compounds of polyurethanes with respect to the crystallization and gelation behaviour in both solid state and solution phase respectively. The aim of my thesis is to investigate the effects on the blending and the gelation of biscarbamates with different alkyl side chain lengths. Melt blending of these molecules shows molecular selectivity and self-sorting behaviour leading to immiscibility. We revealed that the difference in the growth rates of the individual species is responsible for the self-sorting behaviour in these non-chiral synthetic compounds. We discussed methods to bridge the self and non-self that would lead to a more homogeneous system. The gelation properties of biscarbamates with an odd number of carbon atoms in the alkyl side chains, such as the critical gelation concentration, gelation time, gelation temperature, and morphology of the gel fibres were examined. Biscarbamates show odd-even effects in their thermal and gelation behaviours as a function of carbon atom parity in the alkyl side chains in a similar manner to their crystallization behaviours. The blending of the biscarbamate gels shows three different types of blending behaviours. The C8/C9 blend and any gel blends composed of a biscarbamate smaller than C6 display the sergeant-soldier behaviour. The majority rules principle was observed for odd-odd gels blends with an intermediate difference in side chain length. The odd-odd gels blends with a small difference in side chain length self-sort.Organogels with a series of biscarbamates as gelators were prepared using microwave (MW) heating source as well as conventional heating. Biscarbamates with alkyl side chain lengths varying from C5 to C18 were used, with six solvents having dipole moments ranging from 0.07 to 4.3D. The minimum gelation concentration and the amount of heating for ii dissolution were significantly reduced with MW heating with benzonitrile, compared to the conventional heating for all the side chain lengths of the biscarbamates. MW heating is found to be effective with solvents possessing large dipole moments. Although the gels consist of fibers using both methods, an inherent orientation of these fibers was seen with MW heating versus conventional heating methods.iii ACKNOWLEDGEMENTS

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Characteristics of several kinds of polyethylene gel estimated by small‐angle light scattering under cross polarization

Cited by 5 publications

References 44 publications

Influence of Solvent Quality and Crystallization Conditions on the Drawability of Ultra-High Molecular Weight Polyethylene Cast from Solution

Influence of Solvent Quality and Crystallization Conditions on the Drawability of Ultra-High Molecular Weight Polyethylene Cast from Solution

Understandable Unified Description about Diffraction and Scattering of X‐Ray and Visible Light Beams from Soft Matters in Terms of Educational Aspects

Self-Sorting Sergeant-Soldier, and Majority Rules Phenomena in Crystals and Gels of Polyurethane Model Compounds

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