scholarly journals Crystallization behavior of some melt spun Nd–Fe–B alloys

1990 ◽  
Vol 5 (6) ◽  
pp. 1201-1206 ◽  
Author(s):  
M. T. Clavaguera-Mora ◽  
M. D. Baró ◽  
S. Suriñach ◽  
N. Clavaguera
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Crystallization Behavior ◽  
Temperature Limit ◽  
Scanning Calorimetry ◽  
High Temperature Limit ◽  
Activation Energy Of Crystallization ◽  
Melt Spun ◽  
Temperature Transformation ◽  
Scanning Electron

The kinetics of crystallization of four amorphous (or partially amorphous) melt spun Nd–Fe–B alloys induced by thermal treatment is studied by means of differential scanning calorimetry and scanning electron microscopy, In the range of temperatures explored experimentally, the crystallization process is thermally activated and generally proceeds in various stages. The Curie temperature and the crystallization behavior have been measured. The apparent activation energy of crystallization of most of the crystallization stages has been determined for each melt spun alloy. The explicit form of the kinetic equation that best describes the first stage of crystallization has been found. It follows in general the Johnson-Mehl-Avrami-Erofe'ev model, but clear deviations to that model occur for one alloy. Scanning electron microscopy demonstrates that preferentially hetereogeneous nucleation occurs at the ribbon surface which was in contact with the wheel. From crystallization kinetics results the lower part of the experimental time-temperature-transformation curves for all studied alloys are deduced and extrapolated to the high temperature limit of their range of validity, also deduced.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.

Crystallization, Morphology and Mechanical Properties of PLA/PBAT/CaCO3 Composites

2012 ◽  
Vol 602-604 ◽  
pp. 768-771 ◽  
Author(s):  
Nan Shi ◽  
Jun Cai ◽  
Qiang Dou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Crystallization Behavior ◽  
Mechanical Test ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Crystallization Morphology ◽  
Morphology And Mechanical Properties ◽  
Scanning Electron

The melting, crystallization behavior, morphology and mechanical properties of poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT)/calcium carbonate (CaCO3) composites were investigated by means of differential scanning calorimetry (DSC), scanning electron microscopy(SEM), and mechanical test. It is shown that PBAT decreases the crystallinity, while CaCO3 increases the crystallinity of the composites. A synergistic toughening effect is obtained by the combination of CaCO3 and PBAT. The optimum mechanical properties can be achieved in case of the composite (PLA: PBAT: CaCO3=60: 20: 20).

scholarly journals Effect of the dispersion of the chromophore on the optical performances of polarizers from polyethylene and 5”-thio- (3-butyl)nonyl-2,2’:5’,2”-terthiophene

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrea Pucci ◽  
Letizia Moretto ◽  
Giacomo Ruggeri ◽  
Francesco Ciardelli
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Melting Point ◽  
Drawing Ratio ◽  
Scanning Calorimetry ◽  
Affine Deformation ◽  
Ultra High Molecular Weight ◽  
Scanning Electron

AbstractA new polyethylene-compatible terthiophene chromophore, 5”-thio-(3- butyl)nonyl-2,2’:5’,2”-terthiophene, with melting point lower than 0°C was prepared and used for linear polarizers based on ultra-high-molecular-weight polyethylene (UHMWPE). Differential scanning calorimetry and scanning electron microscopy indicate that the new chromophore is dispersed uniformly in films of UHMWPE obtained by casting from solution. The films show excellent dichroic properties (dichroic ratio 30) at rather low drawing ratio (≈ 20) . Moreover, qualitative agreement is observed with the Ward pseudo-affine deformation scheme.

Tensile and flammability characterizations of corn straw slagging/high-density polyethylene composites

2019 ◽  
Vol 33 (11) ◽  
pp. 1466-1477
Author(s):  
Qingfa Zhang ◽  
Wenyu Lu ◽  
Liang Zhou ◽  
Donghong Zhang ◽  
Hongzhen Cai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Flame Retardant ◽  
High Density Polyethylene ◽  
Oxygen Index ◽  
High Density ◽  
Corn Straw ◽  
Scanning Calorimetry ◽  
Scanning Electron

Biocomposites were prepared with corn straw slagging (CSS) and high-density polyethylene (HDPE) at four loading levels (10, 20, 30, and 40 wt%) by extrusion method. CSS/HDPE composites were tested by tension, oxygen index meter, differential scanning calorimetry, X-ray diffraction, and the scanning electron microscopy. The scanning electron microscopy showed that CSS was dispersed uniformly in the HDPE matrix and strong interfacial interaction was achieved, which had an important influence on the tensile strength of the composites. The tensile strength of the composites could be improved with proper increase of CSS and reached maximum value at 30 wt% content. Furthermore, the addition of CSS played an important role in improving the flame-retardant ability of CSS/HDPE composites, and the limited oxygen index was 31.26% at 40 wt% content, good flame-retardant effect achieved.

Influence of Cementitious Capillary Crystalline Waterproofing Material on the Water Impermeability and Microstructure of Concrete

2019 ◽  
Vol 953 ◽  
pp. 209-214
Author(s):  
Yi Teng Zhang ◽  
Lian Zuo ◽  
Jin Chao Yang ◽  
Wei Xia Zhao ◽  
Xiang Xiong Zeng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Cement Matrix ◽  
Hardened Cement ◽  
Hydration Products ◽  
Hardened Cement Paste ◽  
Scanning Calorimetry ◽  
Chinese Standard ◽  
Scanning Electron

The main objective of this study is to investigate the effect of cementitious capillary crystalline waterproofing (CCCW) material on the water impermeability and microstructure of concrete. The water impermeability of concrete covered with or without CCCW material was tested according to the Chinese standard GB 18445-2012. The results indicate that concretes coated with CCCW material showed much higher water impermeability than blank ones, and the ratio of water impermeability pressure between them reached 275. The samples obtained in various depths of hardened cement paste specimens with or without CCCW coating were analyzed through scanning electron microscopy (SEM) and thermogravimetry-differential scanning calorimetry (TG-DSC), to study the differences in microstructure and hydration products. The results present that after a 28-day standard curing, there were lots of ettringite crystals and CaCO3 formed in the paste in 1 cm from the coating, but the action depth of the CCCW coating could not reach 3 cm. The ettringite and CaCO3 is precipitated in the pore structure of cement matrix and filling the voids, which leads to the significant enhancement in water impermeability.

scholarly journals DESIGN AND DEVELOPMENT OF RILPIVIRINE NANOPARTICLE CONTAINING CHITOSAN USING IONIC GELATION METHOD FOR HIV INFECTIONS

2020 ◽  
pp. 113-118
Author(s):  
MONTUKUMAR PATEL ◽  
NIRAV V. PATEL ◽  
TEJAS B. PATEL
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
In Vitro Release ◽  
Amorphous State ◽  
Hiv Infections ◽  
Spherical Particles ◽  
Ionic Gelation ◽  
Scanning Calorimetry ◽  
Scanning Electron

Objective: The primary objective of the current research was to prepare rilpivirine loaded Nanoparticles containing Chitosan using the ionic gelation method for HIV infections. Methods: The nanoparticles of rilpivirine were prepared using the ionic gelation technique. Further, nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and in vitro drug release. Results: The optimized nanoparticles were found with a particle size of 130.30±5.29 nm (mean±SD) and entrapment efficiency (% EE) of 77.10±0.50%. Scanning electron microscopy technique exposed spherical particles with uniform size. It was observed that the nanoparticles created showed the absence of the crystalline nature of the drug and its switch to the amorphous state. Results showed that more than 45% of the pure drug is released in 50 min and after 90 min almost about 95% of the drug is released. Conclusion: The research study concluded that the in vitro release profile of nanoparticles was found to be sustained up to 24 hr. Sustained release of the rilpivirine could improve patient obedience to drug regimens, growing action effectiveness. 

Surface oxides and their effect on the oxidation behavior of amorphous and nanoquasicrystalline Zr–Pd and Zr–Pt alloys

2006 ◽  
Vol 21 (3) ◽  
pp. 639-646 ◽  
Author(s):  
K. Mondal ◽  
U.K. Chatterjee ◽  
B.S. Murty
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oxidation Behavior ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Oxides ◽  
Melt Spun ◽  
The Difference ◽  
Scanning Electron

The oxidation behavior of melt-spun Zr75Pd25 and Zr80Pt20 alloys with nanoquasicrystalline phase embedded in amorphous matrix has been studied isothermally as well as nonisothermally in static air. The nature of oxides formed during oxidation has been studied by x-ray diffraction and scanning electron microscopy, and a transition in the structure of the oxides has been shown as one of the primary reasons for the difference in the oxidation behavior of the alloys.

Effects of Thermal Treatment on the Morphology and Properties of CSM/Poly(Urethane-Isocyanurate) Composites Formed by SRIM Process

2008 ◽  
Vol 575-578 ◽  
pp. 941-946
Author(s):  
Hong Yan Tang ◽  
Ji Hui Wang ◽  
Guo Qiang Gao ◽  
Wen Xing Chen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Treatment Time ◽  
Microphase Separation ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Scanning Electron

Fiberglass continuous strand mat(CSM)/poly(urethane-isocyanurate) composites were formed by SRIM process, treated under different conditions and then characterized based on dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) ,transmission electron microscopy (TEM) and the mechanical property tests. The results show that the mechanical properties of the composites could be increased with improving the degree of microphase separation. At a given temperature (120°C), the degree of microphase separation is the highest for 4h and decreases gradually with prolonging treatment time. For a given time (4h), the well microphase-separated morphology is obtained and the degree of microphase mixing is increased at 120°C and 140°C treatments, respectively. The degree of microphase separation of the composites decreases with enhancing the temperature to 140°C.

Study of an Energetic-oxidant Co-crystal: Preparation, Characterisation, and Crystallisation Mechanism

2017 ◽  
Vol 67 (5) ◽  
pp. 510 ◽  
Author(s):  
Han Gao ◽  
Wei Jiang ◽  
Jie Liu ◽  
Gazi Hao ◽  
Lei Xiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Diffraction Spectrum ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

<p>An energetic co-crystal consisting of the most promising military explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the most well-known oxidant applied in propellants ammonium perchlorate has been prepared with a simple solvent evaporation method. Scanning electron microscopy revealed that the morphology of co-crystal differs greatly from each component. The X-ray diffraction spectrum, FTIR, Raman spectra, and differential scanning calorimetry characterisation further prove the formation of the co-crystal. The result of determination of hygroscopic rate indicated the hygroscopicity was effectively reduced. At last, the crystallisation mechanism has been discussed.</p>

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