20 results on '"Hideki Yamane"'
Search Results
2. Designing with Circular Arc Toolpaths to Increase the Complexity of Melt Electrowriting
- Author
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Huaizhong Xu, Ievgenii Liashenko, Agnese Lucchetti, Lei Du, Yubing Dong, Defang Zhao, Jie Meng, Hideki Yamane, and Paul D. Dalton
- Subjects
Mechanics of Materials ,General Materials Science ,Industrial and Manufacturing Engineering - Published
- 2022
3. Competitive Effects of Stereocomplexation and Hyper-Conjugation of Triethoxysilyl-Terminated Poly(<scp>d</scp> -lactide) in Poly(<scp>l</scp> -lactide) matrices
- Author
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Hideki Yamane, Yoshiharu Kimura, and Jungyub Hyun
- Subjects
Condensation polymer ,Lactide ,Materials science ,Polymers and Plastics ,Hydrosilylation ,General Chemical Engineering ,Organic Chemistry ,technology, industry, and agriculture ,Casting ,chemistry.chemical_compound ,Silanol ,Hydrolysis ,chemistry ,Polymerization ,Polymer chemistry ,Materials Chemistry ,Particle - Abstract
Triethoxysilyl-terminated poly(d-lactide)s (eSi-PDLA) were successfully prepared by hydrosilylation of allyl-terminated PDLAs (A-PDLA-ac) which were readily prepared by ring-opening polymerization of d-lactide and the following terminal protection by acetylation. Their acid-catalyzed hydrolysis produced hyper-conjugated PDLAs with terminal silanol coupling. Blend PLLA films containing eSi-PDLA (Mn = 2.1 kDa) in 5-25 wt.% were successfully prepared by the solution casting method. The blend films were found to take a nano-porous or micro-phase separation structure, being different from that of the blend PLLA films containing trimethoxysilyl-terminated poly(d-lactide) (mSi-PDLA) which exhibited particle distribution structure. This difference was reasonably attributed to the different rate of hydrolytic polycondensation of the trimethoxy- and triethoxy-silyl terminals. These results revealed that the competing sterecomplexation/ hyper-conjugation/phase separation can afford specific morphologies, allowing fine control of properties.
- Published
- 2015
4. Electrospinning of Continuous Aligning Yarns with a ‘Funnel’ Target
- Author
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Amalina M. Afifi, Shigeyuki Nakano, Yoshiharu Kimura, and Hideki Yamane
- Subjects
Jet (fluid) ,business.product_category ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Nozzle ,Electrospinning ,Protein filament ,Bundle ,Orientation (geometry) ,Materials Chemistry ,Fiber ,Funnel ,Composite material ,business - Abstract
A new electrospinning set-up is described for continuous aligning of poly(L-lactide) yarn. It comprises a slowly rotating grounded `funnel' target and a winder placed right up to the funnel. A charged polymer jet is ejected from a nozzle. The electrospun fibers are first accumulated on the mouth plane of the funnel to form a web. The web is then pulled upward and guided to a winder on which twisted fibers are continuously wound as a bundle. Each filament of the bundle is slanted at about 45 relative to the collecting direction, and its average diameter is 6.0+/-1.9 mu m. The drawn fiber shows improved tensile properties as a result of the increased molecular orientation. The morphologies of the twisted fibers before and after drawing are compared.
- Published
- 2010
5. Fabrication of Aligned Poly(L-lactide) Fibers by Electrospinning and Drawing
- Author
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Amalina M. Afifi, Hideki Yamane, Yoshiharu Kimura, Hajime Nakajima, and Shigeyuki Nakano
- Subjects
Materials science ,Fabrication ,business.product_category ,Polymers and Plastics ,Rotor (electric) ,General Chemical Engineering ,Organic Chemistry ,Rotational speed ,Electrospinning ,law.invention ,Synthetic fiber ,law ,Nanofiber ,Microfiber ,Materials Chemistry ,Fiber ,Composite material ,business - Abstract
A new target collector was designed for taking up aligned nanofibers by electrospinning. The collector consists of a rotor around which several fins were attached for winding electrospun filaments continuously in large amounts. The alignment of the nanofibers wound on the collector was affected by the electrospinning conditions, such as the needle-to-collector distance and the applied voltage, but not by the rotation speed of the collector. At a voltage of 0.5 kV · cm -1 , about 60% of the fibers were found to be aligned within an angle of ± 5° relative to the rotational direction of the collector. The fiber alignment was improved to 90% by drawing the fiber bundle 2-3 times at 110°C. The drawing was also effective for crystal orientation of the fibers as revealed by WAXD. The drawn fibers show improved mechanical properties.
- Published
- 2009
6. The effect of poly(ethylene glycol) as plasticizer in blends of poly(lactic acid) and poly(butylene succinate)
- Author
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Hitomi Ohara, Weraporn Pivsa-Art, Yuji Aso, Keiichiro Nomura, Hideki Yamane, and Kazunori Fujii
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Materials science ,Polymers and Plastics ,education ,macromolecular substances ,02 engineering and technology ,Polyethylene glycol ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,PEG ratio ,Ultimate tensile strength ,Polymer chemistry ,Materials Chemistry ,technology, industry, and agriculture ,Plasticizer ,food and beverages ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Polybutylene succinate ,Lactic acid ,chemistry ,Chemical engineering ,Polymer blend ,Elongation ,0210 nano-technology - Abstract
The effect of polyethylene glycol (PEG) on the mechanical and thermal properties of poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blends was examined. Overall, it was found that PEG acted as an effective plasticizer for the PLA phase in these microphase-separated blends, increasing the elongation at break in all blends and decreasing the Tg of the PLA phase. Significant effects on other properties were also observed. The tensile strength and Young's modulus both decreased with increasing PEG content in the blends. In contrast, the elongation at break increased with the addition of PEG, suggesting that PEG acted as a plasticizer in the polymer blends. Scanning electron microscope images showed that the fracture mode of PLA changed from brittle to ductile with the addition of PEG in the polymer blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43044.
- Published
- 2015
7. Higher order structural analysis of stereocomplex-type poly(lactic acid) melt-spun fibers
- Author
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Yukiko Furuhashi, Yoshiharu Kimura, and Hideki Yamane
- Subjects
Birefringence ,Materials science ,Polymers and Plastics ,Annealing (metallurgy) ,Crystal structure ,Condensed Matter Physics ,Amorphous solid ,Lactic acid ,Crystal ,chemistry.chemical_compound ,Crystallography ,Synthetic fiber ,chemistry ,Materials Chemistry ,Physical and Theoretical Chemistry ,Melt spinning - Abstract
The higher order structure of stereocomplex-type poly(lactic acid) melt-spun fibers of an equimolar blend of poly(L-lactic acid) and poly(D-lactic acid) was analyzed with wide-angle X-ray diffraction (WAXD) and birefringence measurements. Two different crystalline structures were observed in the fibers: α-form homocrystals and stereocomplex crystals. The weight fractions of the two crystals were estimated with the WAXD integrated intensity data. The crystalline orientation factors were obtained from the WAXD measurements. Well-oriented homocrystals formed during a drawing process at the crystallization temperature of the homocrystal. Drawing above this temperature caused the stereocomplex crystal to be formed. The crystalline orientation tended to be lower with increasing drawing temperatures. Through the combination of the intrinsic birefringence and the fractions of the α-form homocrystals and stereocomplex crystals, the birefringence of the amorphous phase was evaluated. The amorphous birefringence stayed positive and decreased with increasing drawing temperature.
- Published
- 2006
8. Compression molding and melt-spinning of the blends of poly(lactic acid) and poly(butylene succinate-co-adipate)
- Author
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Keiichiro Nomura, Yuji Aso, Kazunori Fujii, Weraporn Pivsa-Art, Hitomi Ohara, Sommai Pivsa-Art, Kiyoaki Ishimoto, and Hideki Yamane
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Compression molding ,Izod impact strength test ,General Chemistry ,Polymer ,Biodegradable polymer ,Surfaces, Coatings and Films ,Polybutylene succinate ,chemistry ,Ultimate tensile strength ,Materials Chemistry ,Heat deflection temperature ,Polymer blend ,Composite material - Abstract
Poly(lactic acid) (PLA) is a biobased polymer made from biomass having high mechanical properties for engineering materials applications. However, PLA has certain limited properties such as its brittleness and low heat distortion temperature. Thus, the aim of this study is to improve toughness of PLA by blending with poly(butylene succinate-co-adipate) (PBSA), the biodegradable polymer having high toughness. Polymer blends of PLA and PBSA were prepared using a twin screw extruder. The melt rheology and the thermal property of the blends were examined. Further the blends were fabricated into compression molded parts and melt-spun fiber and were subjected to tensile and impact tests. When the PBSA content was low, PBSA phase was finely dispersed in the PLA matrix. On the other hand, when the PBSA content was high, this minor phase dispersed as a large droplet. Mechanical properties of the compression molded parts were affected by the dispersion state of PBSA minor component in PLA matrix. Impact strength of the compression molded parts was also improved by the addition of soft PBSA. The improvement was pronounced when the PBSA phase was finely dispersed in PLA matrix. However, the mechanical property of the blend fibers was affected by the postdrawing condition as well as the PBSA content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41856.
- Published
- 2014
9. X-Ray and Electron Diffraction Study of Poly(p-dioxanone)
- Author
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Teruo Monno, Hideki Yamane, Yutaka Kawahara, Atsushi Nakayama, Yukiko Furuhashi, Tadahisa Iwata, and Yoshiharu Kimura
- Subjects
Materials science ,Polymers and Plastics ,Organic Chemistry ,X-ray ,Poly-p-dioxanone ,Crystal structure ,Isothermal process ,law.invention ,Crystallography ,Electron diffraction ,law ,X-ray crystallography ,Materials Chemistry ,Fiber ,Electron microscope - Abstract
Solution-grown lamellar crystals of poly(p-dioxanone) (PPDX) have been crystallized isothermally from butane-1,4-diol at 100°C. The crystal structure of PPDX has been determined by interpretation of X-ray fiber diagrams of PPDX fibers and electron diffraction diagrams of lozenge-shaped chain-folder lamellar crystals. The unit cell of PPDX is orthorbombic with space group P2 1 2 1 2 1 and parameters: a=0.970 nm, b=0.74 mm, and c (chain axis) = 0.682 nm. There are two chains per unit cell, which exist in an anti parallel arrangement.
- Published
- 2004
10. Processing of a Strong Biodegradable Poly[(R)-3-hydroxybutyrate] Fiber and a New Fiber Structure Revealed by Micro-Beam X-Ray Diffraction with Synchrotron Radiation
- Author
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Akihisa Takeuchi, Yoshiharu Doi, Yoshio Suzuki, Tadahisa Iwata, Hideki Yamane, Yoshihiro Aoyagi, Kentaro Uesugi, and Masahiro Fujita
- Subjects
Diffraction ,Materials science ,Polymers and Plastics ,Annealing (metallurgy) ,Organic Chemistry ,X-ray ,Synchrotron radiation ,Crystallography ,Synthetic fiber ,Zigzag ,X-ray crystallography ,Ultimate tensile strength ,Materials Chemistry ,Composite material - Abstract
Biodegradable poly[(R)-3-hydroxybutyrate| (P(3HB)) fibers with high tensile strength of 1.32 GPa were processed from ultra-high-molecular-weight P(3HB) by a method combining cold-drawing and two-step-drawing procedures at room temperature. The distribution of molecular structures in a mono-filament was analyzed by micro-beam X-ray diffraction with synchrotron radiation. It was revealed that the P(3HB) fiber has a new core-sheath structure consistent with two types of molecular conformations: a 2 1 helix conformation in the sheath region and a planar zigzag conformation in the core region.
- Published
- 2004
11. Effect of steric hindrance on hydrogen-bonding interaction between polyesters and natural polyphenol catechin
- Author
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Haruo Nishida, Jianchun Li, Bo Zhu, Hideki Yamane, Yong He, Yoshiharu Kimura, and Yoshio Inoue
- Subjects
Steric effects ,Polymers and Plastics ,Hydrogen bond ,Catechin ,General Chemistry ,Miscibility ,Surfaces, Coatings and Films ,Polyester ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,Polymer chemistry ,Materials Chemistry ,Phenol ,Glass transition - Abstract
The phase behaviors for the blends of poly(3-hydroxypropionate) (PHP), poly(L-lactide) (PLLA), poly(D-lactide) (PDLA), and poly(D,L-lactide) (PDLLA) with catechin were investigated by differential scanning calorimetry. In PLLA/catechin, PDLA/catechin, and PDLLA/catechin blends, two glass transitions were detected when the catechin content was ≥40 wt %, whereas in PHP/catechin blends only one glass transition was observed over the whole range of blend compositions. The former and the latter results should reflect the inhomogeneous and the homogeneous nature of the blends, respectively, in the amorphous phase. These different phase behaviors should arise from the differences in the chemical structures between PHP and PLLA/PDLA/PDLLA, which dominates the strength and the number of intermolecular hydrogen-bonding interactions between the ester carbonyl groups of polyesters and the phenol groups of catechin. As detected by FTIR spectroscopy, in comparison with PHP, the steric hindrance of side-chain methyl groups of PLLA, PDLA, and PDLLA might restrain the formation of hydrogen bonds between their ester carbonyl groups and the phenol hydroxyl groups of catechin, even weakening the strength of such hydrogen bonds. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3565–3573, 2004
- Published
- 2004
12. Chemical Modification and some Aligned Composites of Chitosan in a Filament State
- Author
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Yoshiharu Kimura, Kojiro Matsukawa, Hideki Yamane, Shigehiro Hirano, Min Zhang, and Masuo Nakagawa
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Materials science ,Polymers and Plastics ,fungi ,technology, industry, and agriculture ,Chemical modification ,Fibroin ,Bioengineering ,macromolecular substances ,Sericin ,Biomaterials ,Protein filament ,Chitosan ,Hydrolysis ,chemistry.chemical_compound ,SILK ,chemistry ,Polymer chemistry ,Materials Chemistry ,Polymer blend ,Composite material ,Biotechnology - Abstract
The mono-filaments (> 10 m in length) of chitosan and the blends of chitosan-collagen, chitin-collagen and chitin-silk fibroin were wet-spun. The mono-filaments were chemically N-modified with each of n-fatty acid anhydrides, intra-molecular carboxylic anhydrides, fragrant aldehydes and transition metal ions. The mono-filament was aligned on a straight line with the mono-filament of silk fibroin or poly(ethylene terephthalate) (PET), and a bundle of one to three mono-filaments was coated with a medium of sericin (Se), chitosan or N-acylchitosan to give rise to novel silk-mimic filament composites. The filaments coated with a medium of sericin exhibited 26-27 denier for the titer, 2.46-3.36 gf.denier -1 for the tenacity and 11.8-25.0% for the elongation. The apparent density (denier.μm -1 in the filament diameter) of the filament composites was about 3-4 times higher than that of the mono-filaments. Portion of fragrant aldehydes in Schiff's base was slowly hydrolyzed at room temperature by contacting with atmospheric moisture in the open air, and released from the fragrant filaments and composites. The filament composites coated with a chitosan medium were thrombogenic, and those coated with N-acylchitosans were antithrombogenic.
- Published
- 2003
13. Effect of the melt-mixing condition on the physical property of poly(<scp>l</scp> -lactic acid)/poly(<scp>d</scp> -lactic acid) blends
- Author
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Masaki Yamamoto, Yoko Fukui, Esraa El-Khodary, and Hideki Yamane
- Subjects
Materials science ,Polymers and Plastics ,Nucleation ,02 engineering and technology ,General Chemistry ,Transesterification ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,law.invention ,Lactic acid ,Physical property ,Crystal ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,law ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Crystallization ,0210 nano-technology - Abstract
The effect of the mixing condition in a mill-type mixer on the thermal property and the crystal formation of the poly(l-lactide)/poly(d-lactide) blends is investigated. The blends melt-mixed at 200 and 210 °C under application of a high shear flow tend to show a single melting peak of the stereocomplex crystal (SC) in the differential scanning calorimetry first and second heating processes without indicating the trace of the melting of homo-chiral crystal. The mixing at an elevated temperature causes a serious thermal degradation. Further kneading of the blends at an elevated temperature higher than Tm of SC causes the transesterification between the same enatiomeric chains forming block copolymers of l- and d-chains. This block copolymer acts as a nucleating agent of SC and the compatibilizing agent between poly(l-lactide) and poly(d-lactide) and promotes the formation of SC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45489.
- Published
- 2017
14. Cover Picture: Macromol. Mater. Eng. 11/2015
- Author
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Yoshiharu Kimura, Hideki Yamane, and Jungyub Hyun
- Subjects
Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Materials Chemistry ,Cover (algebra) ,Physical geography - Published
- 2015
15. Molecular mechanical analysis of polymer conformation, 2. Relation between chain conformation and birefringence of stretched non-crystalline polyurethanes with various substituent groups
- Author
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Hideki Yamane, Masakazu Konda, Toshio Kitao, and Yoshiharu Kimura
- Subjects
chemistry.chemical_classification ,Steric effects ,Birefringence ,Polymers and Plastics ,Organic Chemistry ,Substituent ,Polymer ,Condensed Matter Physics ,chemistry.chemical_compound ,Draw ratio ,chemistry ,Chain (algebraic topology) ,Polarizability ,Polymer chemistry ,Materials Chemistry ,Phenyl group ,Physical and Theoretical Chemistry - Abstract
The relationship between birefringence and polymer structure was studied both by theoretical and experimental analyses of a series of non-crystalline polyurethanes (PU) with different side groups. The most probable steric structures of PUs were estimated by molecular mechanical calculation (MM2) of their oligomeric model compounds, and their birefringence was theoretically calculated on the structural data obtained. In addition, some of the PUs were practically synthesized and melt-spun into thin fibers, which were drawn to a maximum draw ratio to measure the values of birefringence. The comparison of the measured and estimated values revealed that the present estimation method is effective for simulating the chain conformations and the birefringence of fully or partially extended polymer chains, which ought to be formed by drawing and melt-flow of glassy materials. Of particular interest was that phenyl-substituted PUs exhibit an unexpectedly larger birefringence than methyl-substituted PUs. This fact was reasonably explained by the angular rotation of the highly polarizable phenyl group, which is energetically easily allowed and influences strongly the value of birefringence.
- Published
- 1994
16. Alumina–carbon composite fibers from poly[(acyloxy)aloxane]s
- Author
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Yoshiharu Kimura, Koichi Hashimoto, Hideki Yamane, and Toshio Kitao
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Composite number ,chemistry.chemical_element ,Sintering ,General Chemistry ,Polymer ,Surfaces, Coatings and Films ,Solvent ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Materials Chemistry ,Fiber ,Carboxylate ,Pyrolysis ,Carbon - Abstract
The alumina–carbon composite fibers were obtained from poly[(acyloxy)aloxane] (PAA) with 3-ethoxypropanoic (EPA) and m-anisic acids (m-AA) legands. This preceramic polymer can be dissolved in p-xylene-methanol-EPA mixed solvent, and the concentrated solution exhibited an excellent spinnability. During the pyrolysis and sintering processes, aliphatic carboxylate in the side groups was easily decomposed and eliminated. The aromatic carboxylate, however, seems to be converted and migrated to a carbon domain in the alumina matrix into which aloxane repetition was converted. The fibers pyrolyzed up to 800 and 1000°C have electrical conductivities that monotonically increase with increasing temperature. The fiber pyrolyzed up to 1200°C showed the electrical conductivity in a rather complicated manner.
- Published
- 1992
17. Macromol. Mater. Eng. 10/2009
- Author
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Yoshiharu Kimura, Amalina M. Afifi, Shigeyuki Nakano, Hideki Yamane, and Hajime Nakajima
- Subjects
Materials science ,Polymers and Plastics ,Polymer science ,General Chemical Engineering ,Organic Chemistry ,Materials Chemistry - Published
- 2009
18. Alumina fibers from poly[((3-ethoxypropanoyl)oxy)aloxane]
- Author
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Hideki Yamane, Yoshiharu Kimura, Hisao Morita, and Toshio Kitao
- Subjects
Materials science ,Polymers and Plastics ,Scanning electron microscope ,Sintering ,General Chemistry ,Surfaces, Coatings and Films ,Thermogravimetry ,Phase (matter) ,Differential thermal analysis ,Materials Chemistry ,Extrusion ,Fiber ,Composite material ,Spinning - Abstract
Alumina fibers were obtained from the poly[((3-ethoxypropanoyl)oxy)aloxane] (P-3EPA) by using a polymeric precursor technology. The rheological properties of the concentrated solution of P-3EPA related to the extrusion and spinning processes have been investigated to determine the processability into fine filaments. Thirty weight percent P-3EPA dissolved into toluene showed an excellent spinnability and fine filaments of 20–30 μm in diameter were easily obtained. The phase changes during the sintering of the fiber were studied with wide-angle X-ray diffraction and were shown to be strongly related to the mechanical properties of the fiber. Further the addition of the ethyl silicate (ES) as a sintering agent which prevent the crystal growth of Al2O3 was found to be effective to improve the mechanical properties of the alumina fiber.
- Published
- 1990
19. Cover Picture: Macromol. Rapid Commun. 23/2004
- Author
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Yukiko Furuhashi, Hideki Yamane, Teruo Monno, Yutaka Kawahara, Yoshiharu Kimura, Atsushi Nakayama, and Tadahisa Iwata
- Subjects
Materials science ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry ,Cover (algebra) ,Remote sensing - Published
- 2004
20. Extrusion and melt spinning characteristics of thermally degraded polypropylene
- Author
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James L. White and Hideki Yamane
- Subjects
Polypropylene ,Materials science ,Polymers and Plastics ,General Chemistry ,Die swell ,Swell ,Viscosity ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Degradation (geology) ,Molar mass distribution ,Extrusion ,Composite material ,Melt spinning - Abstract
A basic study of the influence of thermal degradation of polypropylene on its extrudate swell and melt spinning characteristics is reported. The degradation reduces swell, changes the shape of the spinline diameter/velocity profile (i.e., the spinline apparent elongational viscosity function), and stabilizes the melt spinning process. The importance of molecular weight distribution narrowing during the degradation process is noted in these studies.
- Published
- 1983
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