The phase transition of polyamide 6 with pre-stretching process at different temperatures

2021 ◽  
Author(s):  
Ziqing Cai ◽  
Jinqiao Ye ◽  
Yunfan Zhang ◽  
Danli Nie ◽  
Ouyang Jianglin
Keyword(s):  
Crystal Structure ◽  
Crystal Morphology ◽  
Structural Evolution ◽  
Polyamide 6 ◽  
Key Factors ◽  
Strain Fields ◽  
Molding Method ◽  
Different Temperatures ◽  
Stretching Process ◽  
Thermal Stable

Abstract The temperature and strain fields are two key factors in the regulation of fibrous aggregate structure. In this paper, plate specimens of polyamide 6 were prepared by compression molding method. The oriented polyamide 6 plates were systematically analyzed from aspects of mechanical properties, thermal properties, crystal structure and crystal morphology. The maximum tensile strength and elastic modulus of polyamide 6 plate appeared at 120℃. The stretching process induced the formation of a more thermal stable α-form crystals. With the increase of stretching temperature, α-form crystals transformed into γ-form crystals gradually. The crystal chips transformed into fibrils during the stretching process. The structural evolution model of materials under the temperature and strain fields was established.

scholarly journals Synthesis of magnesium carbonate hydrate from natural talc

2020 ◽  
Vol 18 (1) ◽  
pp. 951-961
Author(s):  
Qiuju Chen ◽  
Tao Hui ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Wenjin Ding
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Crystal Growth ◽  
Crystal Morphology ◽  
Magnesium Carbonate ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
X Ray ◽  
Carbonation Process

AbstractVarious morphologies of magnesium carbonate hydrate had been synthesized without using any organic additives by carefully adjusting the reaction temperature and time during the talc carbonation process. At lower temperatures, magnesium carbonate hydrate was prone to display needle-like morphology. With the further increase of the carbonation temperature, the sheet-like crystallites became the preferred morphology, and at higher aging temperatures, these crystallites tended to assemble into layer-like structures with diverse morphologies, such as rose-like particles and nest-like structure. The reaction time had no effect on the crystal morphology, but it affected the particle size and situation of the crystal growth. X-Ray diffraction results showed that these various morphologies were closely related to their crystal structure and compositions. The needle-like magnesium carbonate hydrate had a formula of MgCO3·3H2O, whereas with the morphological transformation from needle-like to sheet-like, rose-like, and nest-like structure, their corresponding compositions also changed from MgCO3·3H2O to 4MgCO3·Mg(OH)2·8H2O, 4MgCO3·Mg(OH)2·5H2O, and 4MgCO3·Mg(OH)2·4H2O.

Effect of thermally reduced graphene oxides obtained at different temperatures on the barrier and mechanical properties of polypropylene/TRGO and polyamide‐6/TRGO nanocomposites

2018 ◽  
Vol 40 (S2) ◽  
pp. E1746-E1756 ◽  
Author(s):  
Moisés Gómez ◽  
Alexis Díaz ◽  
Paula Reyes ◽  
Mehrdad Yazdani‐Pedram ◽  
Sônia Marlí Bohrz Nachtigall ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyamide 6 ◽  
Graphene Oxides ◽  
Reduced Graphene ◽  
Different Temperatures ◽  
Reduced Graphene Oxides

Crystal Structure of La1−xCexCoO3+δ (x ≤0.1) nanoparticles at different temperatures

2008 ◽  
Author(s):  
Ganbat Batdemberel ◽  
Gochoo Bulgan ◽  
Zhu Yongfa ◽  
Deleg Sangaa ◽  
Robert Dinnebier ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Different Temperatures

Effects of molding on property of thermally conductive and electrically insulating polyamide 6–based composite

2018 ◽  
Vol 32 (9) ◽  
pp. 1190-1203 ◽  
Author(s):  
Xuping Yang ◽  
Wenbin Yang ◽  
Jinghui Fan ◽  
Juying Wu ◽  
Kai Zhang
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Injection Molding ◽  
Annealing Time ◽  
Polyamide 6 ◽  
Molding Pressure ◽  
Hot Press ◽  
Molding Method ◽  
Thermally Conductive ◽  
Press Molding

Thermally conductive and electrically insulating polyamide 6 (PA6) matrix quaternary composites were prepared by hot press molding and injection molding, respectively. The quaternary composites were composed of zero-dimensional aluminum oxide particle, one-dimensional silicon carbide whisker, two-dimensional flake graphite, and PA6 resin matrix. Morphology, structure, density, thermal conductivity, volume electrical resistivity, and tensile strength of two types of composites were characterized by scanning electron microscopy, X-ray diffractometer, thermal conductivity tester, high resistance micro-current tester, and tensile tester. The results showed that crystallinity, thermal conductivity, density, and tensile strength of hot press molding samples were superior to those of samples made by injection molding method. This is due to that hot press molding method can provide higher molding pressure and longer annealing time than injection molding. The mechanism could be explained that the performances of the composites were promoted by increasing molding pressure and annealing time.

scholarly journals Morphological and Thermal Properties of Poly(Vinyl Alcohol)/Layered Double Hydroxide Hybrid Nanocomposite Fibers

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
A. F. Al Naim ◽  
J. Mazher ◽  
S. S. Ibrahim
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Layered Double Hydroxide ◽  
Vinyl Alcohol ◽  
Separation Distance ◽  
Molecular Vibration ◽  
Poly Vinyl Alcohol ◽  
Rapid Weight Loss ◽  
Different Temperatures ◽  
Double Hydroxide

Nanolayered particulate of Zn-based layered double hydroxide (LDH) was prepared by a low temperature greener sol-gel method. X-ray diffraction (XRD) studies were performed on the particles annealed at different temperatures. Hexagonal crystal structure of the as-grown LDH particulates was observed. The crystal structure was modified to tetragonal structure of layered double oxide (LDO) on annealing at 250°C. Rietveld fittings showed a collapse of interlayer separation distance along the preferred orientation of the LDH particles as a result of heat treatment. Further, LDH particles were used as fillers of electrospun poly(vinyl alcohol) (PVA) fibers. Heat treatment of the polymer fibers was also performed at different temperatures, and thermal changes were studied by thermogravimetric analysis (TGA), Raman spectroscopy, and scanning electron microscopy (SEM) techniques. Improved interaction of fibers with LDH nanoparticles was observed and ascribed to LDH-related LDO phase transformation at higher temperature. Thermal mechanisms of the rapid weight loss in filled fibers were discussed in comparison to the pure PVA fiber losses. Experimental Raman frequencies of the composite fibers were compared with the calculated Raman modes of the enol and ZnO monomers. The molecular vibration frequencies were found to differ significantly due to heat treatment. Finally, the role filler in the faster and greener thermal decomposition of polymeric fibers was also discussed in the present work.

Crystal structure, crystal morphology, and surface properties of an investigational drug

2009 ◽  
Vol 368 (1-2) ◽  
pp. 76-82 ◽  
Author(s):  
Y.-H. Kiang ◽  
Chia-Yi Yang ◽  
Richard J. Staples ◽  
Janan Jona
Keyword(s):  
Crystal Structure ◽  
Surface Properties ◽  
Crystal Morphology ◽  
Investigational Drug

Strain Rules of Cross Wedge Rolling Asymmetric Shaft-Parts Based on the Parity Wedge

2012 ◽  
Vol 201-202 ◽  
pp. 1066-1070
Author(s):  
Zhan Li ◽  
Xue Dao Shu ◽  
Wen Fei Peng ◽  
Bao Shou Sun
Keyword(s):  
Theoretical Foundation ◽  
Longitudinal Section ◽  
Rolling Process ◽  
Field Analysis ◽  
Key Factors ◽  
Cross Wedge Rolling ◽  
Forming Process ◽  
Cross Sectional ◽  
Strain Fields ◽  
Forming Mechanism

The analysising of strain is the key factors to understand the forming mechanism of cross wedge rolling asymmetric shaft. due to the extrusion of dies and other external force, its interior,interactions can cause the relative position between the various parts. In order to study the deformation of workpiece at different degrees, pulling in the finite element strain field analysis, the strain of the analysis at deformation process is also a necessary precondition for forming and stress distribution. In this papre,By using Deform3D platform, the forming process of the cross wedge rolling on parity wedge asymmetric shaft is simulated. It is also to be analyzed the distribution and variation of the amount of strain in the rolling process, it shows that a cross-sectional and longitudinal section about the deformation characteristics of the strain fields, the results can achieve production of cross wedge rolling and provide important theoretical foundation to promote further cross-wedge rolling.

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