Structure and performance of polybutene-1 pipes produced via mandrel rotation extrusion

2014 ◽  
Vol 34 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Wei Liu ◽  
Qi Wang ◽  
Min Nie
Keyword(s):  
Rotation Speed ◽  
Processing System ◽  
Axial Direction ◽  
Amorphous Region ◽  
Thermal Shrinkage ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Extrusion Processing ◽  
And Performance ◽  
Mechanical Performances

Abstract In this article, a new rotational extrusion processing system was adopted for manufacturing of polybutene-1 (PB-1) pipes, and the effects of mandrel rotation speed on their structures and mechanical performances were studied. The experimental results showed that besides the conventional axial extrusion flow field, a hoop shear stress field imposed to the melt, which was generated by the introduction of mandrel rotation, could lead the combined stress apart from the axial direction of the pipes to induce the molecular orientation deviated from the axial direction. Thus, the axial orientation of PB-1 was restrained, which was revealed by thermal shrinkage measurements and polarized infrared spectra. Moreover, it was also found and confirmed by scanning electron microscopy and two-dimensional wide-angle X-ray diffraction that orientation mainly existed in the amorphous region rather than the crystal region. Differential scanning calorimetry tests showed that the mandrel rotation could facilitate the formation of more perfect crystals and higher crystallinity. As a result, compared with the PB-1 pipe produced by conventional extrusion, the hoop strength of the PB-1 pipes manufactured at a mandrel rotation speed of 8 rpm increased from 20.2 to 24.9 MPa, achieving a mechanical balance in both axial and hoop directions.

scholarly journals Influence of early thermal-oxidative ageing on the structure and properties of polyoxymethylene copolymer

2021 ◽  
Vol 8 (6) ◽  
pp. 210034
Author(s):  
Yuan-Jin Pang ◽  
Wen-Shuai Xu ◽  
Ben-Tengzi Yang ◽  
Hai-Ying Ni ◽  
Jun Chen
Keyword(s):  
Amorphous Region ◽  
Chain Scission ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystallinity Degree ◽  
Region I ◽  
The Difference ◽  
And Performance ◽  
Oxidative Ageing

Thermal-oxidative ageing of polyoxymethylene (POM) copolymer in the oven at 100°C for 1, 2, 3, 5, 7, 10, 14 and 21 days and the influence of early thermal-oxidative ageing on POM structure and properties were studied by means of wide-angle X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and tensile test. Based on the results, we found that the early thermal-oxidative ageing of POM copolymer can be divided into three regions. The region I is the initial 3 days. In this region, some molecular chains rearranged, resulting in internal stress relaxation, increase of crystallinity degree and grain size due to the perfection of crystal structure; both extended chain crystal (ECC) and folded chain crystal (FCC) increased and ECC grew faster than FCC. The region II is from 3 days to 10 days, and in this region, chain scission took place in amorphous region and led to chemi-crystallization. The region III is after 10 days. In this region, the structure and performance of POM copolymer reached a stable situation at this stage. In this work, the difference between skin and core were also analysed.

Effect of Modified NanoSiO2 Agents on the Morphologies and Performances of UHMWPE Microporous Membrane via Thermally Induced Phase Separation

2016 ◽  
Vol 848 ◽  
pp. 726-732 ◽  
Author(s):  
Rong Liu ◽  
Yan Wang ◽  
Jing Zhu ◽  
Zu Ming Hu ◽  
Jun Rong Yu
Keyword(s):  
Phase Separation ◽  
Water Flux ◽  
Microporous Membranes ◽  
Thermally Induced Phase Separation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermally Induced ◽  
And Performance ◽  
Surface Modified ◽  
Ultra High Molecular Weight

The effects of Modified NanoSiO2 Agents on the morphology and performance of ultra-high-molecular weight polyethylene (UHMWPE) microporous membranes via thermally induced phase separation were investigated in this work. The NanoSiO2 was surface modified by silane coupling agent KH570 (KH570-NanoSiO2). Differential scanning calorimetry (DSC) and X-Ray Diffraction (XRD) were performed to obtain crystallization of UHMWPE/white oil/ KH570-NanoSiO2 doped system. The morphology and performance of the prepared UHMWPE microporous membranes were characterized with scanning electron microscopy (SEM) and microfiltration experiments. The results showed that the morphology of UHMWPE membrane could be disturbed by KH570-NanoSiO2. Porosity and the rejection of Bovine serum albumin (BSA) of the blend membrane increased with increasing concentration of Modified NanoSiO2, while the water flux slightly decreased.

scholarly journals Microstructure Evolution and Performance Improvement of Hypereutectic Al–Mg2Si Metallic Composite with Ca or Sb

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2714
Author(s):  
Min Zuo ◽  
Boda Ren ◽  
Zihan Xia ◽  
Wenwen Ma ◽  
Yidan Lv ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nucleation Behavior ◽  
X Ray ◽  
Primary Mg2si ◽  
Before And After ◽  
And Performance ◽  
Hardness Values

In this article, the modification effects on Al–Mg2Si before and after heat treatment were investigated with Ca, Sb, and (Ca + Sb). In comparison with single Ca or Sb, the samples with composition modifiers (Ca + Sb) had the optimal microstructure. The sample with a molar ratio for Ca-to-Sb of 1:1 obtained relatively higher properties, for which the Brinell hardness values before and after heat treatment were remarkably increased by 31.74% and 28.93% in comparison with bare alloy. According to differential scanning calorimetry analysis (DSC), it was found that the nucleation behavior of the primary Mg2Si phase could be significantly improved by using chemical modifiers. Some white particles were found to be embedded in the center of Mg2Si phases, which were deduced to be Ca5Sb3 through X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM) analyses. Furthermore, Ca5Sb3 articles possess a rather low mismatch degree with Mg2Si particles based on Phase Transformation Crystallography Lab software (PTCLab) calculation, meaning that the efficient nucleation capability of Ca5Sb3 for Mg2Si particles could be estimated.

Novel Aceclofenac cocrystals with l-Cystine: Virtual coformer screening, mechanochemical synthesis, and physicochemical investigations

2020 ◽  
Vol 17 ◽  
Author(s):  
Saroj Kumar ◽  
Amresh Gupta ◽  
Rammani Prasad ◽  
Satyawan Singh
Keyword(s):  
Dissolution Rate ◽  
Mechanochemical Synthesis ◽  
Screening Method ◽  
Research Work ◽  
Crystalline Solid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Grinding Method ◽  
Enhanced Solubility ◽  
And Performance

Aim: Current work focuses on the improvement of solubility and dissolution of ACF by the cocrystal approach. Background: Aceclofenac (ACF) is one of the commonly used nonsteroidal anti-inflammatory drug (NSAID) representing the variety of therapeutic applications including management of pain, inflammation, rheumatoid arthritis, and osteoarthritis, etc. But very low solubility and dissolution rate of ACF compromise its therapeutic utility. Now a day's cocrystallization technique has emerged as a novel technique for modulation of said problems. Objective: The Specific objectives of this research work were mechanochemical synthesis, characterization, and performance evaluation of aceclofenac cocrystal. Method: ACF was screened with various pharmaceutically acceptable coformers (Selected from GRAS and EAFUS list) using MOPAC software and physical screening method to find out novel cocrystals of ACF with enhanced solubility and dissolution rate. Novel cocrystals (multi-component crystalline solid) of ACF with l-cystine were prepared by neat grinding method and by liquid assisted grinding method. The synthesized cocrystals (ACF-l-CYS NG and ACF-l-CYS LAG) were characterized carefully by differential scanning calorimetry (DSC), infrared spectroscopy (IR), and powder X-ray diffraction (PXRD) to verify the formation of the cocrystals. Pharmaceutically significant properties such as powder dissolution rate, solubility, and stability of the prepared cocrystals were evaluated. Results: Compared to pure ACF, the prepared cocrystals showed superior solubility and dissolution rate. The prepared cocrystals were found to be stable and non-hygroscopic under study conditions. Conclusion: The cocrystallization technique was successfully utilized to increase the solubility and dissolution rate of aceclofenac.

Chalcogenide glasses Ge–Sn–Se, Ge–Se–Te, and Ge–Sn–Se–Te for infrared optical fibers

1990 ◽  
Vol 5 (6) ◽  
pp. 1215-1223 ◽  
Author(s):  
I. Haruvi-Busnach ◽  
J. Dror ◽  
N. Croitoru
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Fibers ◽  
Chalcogenide Glasses ◽  
Glass Composition ◽  
Amorphous Region ◽  
Maximum Power Density ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ftir Spectrometry

Chalcogenide glasses of the systems Ge–Sn–Se, Ge–Se–Te, and Ge–Sn–Se–Te have been prepared. Several compositions were found suitable for drawing fibers for CO2 laser radiation (λ = 10.6 μm) transmission. The glasses were characterized by x-ray diffraction, DSC (Differential Scanning Calorimetry), SEM with EDX analysis, FTIR spectrometry, density, and microhardness measurements. The glass transition temperature and microhardness of Ge–Se–Sn and Ge–Sn–Se–Te glasses decreased with increasing Sn content, for most of the samples. The region of high IR transparency of Ge–Se–Sn, Ge–Se–Te, and Ge–Sn–Se–Te glasses was slightly expanded (1–2 μm) toward longer wavelengths, compared to Ge–Se glasses, mainly for the glasses containing 70 at.% Se. The intensity of the impurity absorption peak of Ge–O (at λ ∼ 12.8 μm), which usually appears in Ge–Se glasses, was reduced or absent in Ge–Sn–Se–Te glasses. The best fibers were produced with the glass composition Ge–0.8Sn0.2Se3.5Te0.5. An attenuation of 20 dB/m at 10.6 μm, and a transmitted maximum power density of 2.4 ⊠ 106 W/m2 were measured. The mechanical and optical characteristics of these glasses have been related to the glasses structure. Corresponding to the reduced masses of the bonds formed in the Ge–Sn–Se–Te system (in the amorphous region), it is expected that the multiphonon edge is slightly shifted. As a consequence, as was measured, the transparency region has been expanded by less than 2 μm toward longer wavelengths.

Structure and Performance of PP Porous Membrane Prepared with Adipic Acid and NA-40 as Nucleating Agent via TIPS

2016 ◽  
Vol 848 ◽  
pp. 733-737
Author(s):  
Hui Xia Xuan ◽  
Chun Ju He
Keyword(s):  
Adipic Acid ◽  
Water Flux ◽  
Nucleating Agent ◽  
Porous Membrane ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Thermally Induced ◽  
Cooling Temperature ◽  
And Performance

Polypropylene (PP) membranes were respectively prepared using adipic acid (APA) and Sorbitol (NA-40) as nucleating agent via thermally induced phase separation (TIPS) method. The effects of nucleating agent content and cooling temperature on the structure and performance of membrane were investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). WAXD spectrogram indicates that three kinds of α, β and γ-form crystal were formed in this preparation process and the relative content of β-form crystal in membrane prepared by NA-40 system is higher than that of membrane formed by adipic acid. SEM images show that porous structure and cellular structure were observed on the surface and cross-section of membrane. The water flux, tensile strength and elongation increase with the addition of nucleating agent content and decrease with cooling temperature rising. This paper aims to choose proper nucleating agent NA-40 and coagulation temperature to improve the properties of PP membranes.

Structure and properties of ethylene-tetrafluoroethylene fibers fabricated by melt spinning

2017 ◽  
Vol 88 (10) ◽  
pp. 1112-1124 ◽  
Author(s):  
Lele Sun ◽  
Changfa Xiao ◽  
Jian Zhao ◽  
Shulin An ◽  
Shichao Zhang
Keyword(s):  
Melt Spinning ◽  
Room Temperature ◽  
Breaking Strength ◽  
Fiber Strength ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
And Performance ◽  
Ethylene Tetrafluoroethylene

Ethylene-tetrafluoroethylene (ETFE) fibers were fabricated by a single-screw melt spinning machine at different drawing roll speed ratios and different drawing roll temperatures. Thermogravimetric analyzer, differential scanning calorimetry, X-ray diffraction (XRD), digital fiber sound velocimeter and single fiber strength testers were used to discuss the impacts of spinning processes on the structure and performance of ETFE fibers. The results indicated that four different fibers showed a similar melting temperature at around 257℃. XRD results revealed that the largest crystallinity of four ETFE fibers was 41.1%. As the drawing temperature increased, the crystallinity of ETFE fibers decreased and the grain size increased. The breaking strength of four as-spun ETFE fibers reached up to 1.12 cN/dtex. The minimum shrinkage of ETFE fibers at 200℃ was 7%, and it was only 1% at most below 150℃. The maximum creep strain of ETFE fibers was 6% when the loading capacity was 20% of the breaking strength at room temperature and ETFE fibers had a high recovery ratio of >90% after the load was removed. Moreover, ETFE fibers showed exceptional corrosion resistance and good performance of irradiation resistance.

Design and synthesis of high heat-resistant, soluble, and hydrophobic fluorinated polyimides containing pyridine and trifluoromethylthiophenyl units

2017 ◽  
Vol 31 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Xiaohua Huang ◽  
Hua Li ◽  
Chanjuan Liu ◽  
Chun Wei
Keyword(s):  
Raw Materials ◽  
High Heat ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Hydrophobic Property ◽  
Scanning Calorimetry ◽  
Design And Synthesis ◽  
Fluorinated Polyimides ◽  
And Performance ◽  
Tetracarboxylic Dianhydride

In this study, a novel diamine monomer, 4-(4-trifluoromethylthiophenyl)-2,6-bis(4-aminophenyl)pyridine (FTPAP) was synthesized through two-step reaction from 4-trifluoromethylthiobenzaldehyde and 4-nitroacetophenone as raw materials, and then the structure of FTPAP was characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance, and mass spectrometry. A series of fluorinated polyimides were prepared from FTPAP with five commercial dianhydrides, namely, pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphtahalic anhydride, benzophenone tetracarboxylic dianhydride, and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride. The structure and performance of the fluorinated polymers were fully characterized by FTIR, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction (WAXD). The inherent viscosity of polymers ranged from 0.41 to 1.45 dL g−1. These polymers displayed good solubility in polar aprotic solvents, such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone, at room temperature or on heating. Furthermore, they exhibited outstanding thermal stability with glass transition temperatures beyond 305°C, and the temperature of 10% weight loss was in the range of 514–573°C with more than 56% residue at 800°C under nitrogen. Moreover, they showed high optical transparency with the cutoff wavelengths in the range of 385–457 nm and excellent hydrophobic property with contact angle in the range of 82.8–97.6°. In addition, the results of WAXD indicated that all of the polymers presented amorphous structure.

scholarly journals Effect of Potassium Permanganate Modification on Plasticized Spinning Polyacrylonitrile Fibers with Different Diameters

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1330
Author(s):  
Xiang Li ◽  
Xiaonan Dang
Keyword(s):  
Potassium Permanganate ◽  
Large Diameter ◽  
Small Diameter ◽  
Amorphous Region ◽  
Treatment Temperature ◽  
Crystalline Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Different Diameters ◽  
First Time

Plasticized spinning polyacrylonitrile (PAN) fibers with different diameters were chemically modified by potassium permanganate (KMnO4). The modification effects of different diameter fibers were studied for the first time. Differential scanning calorimetry (DSC) results show that, compared with the large diameter ones, small diameter modified fibers show lower cyclization starting temperature (Ti) and activation energy (E). Both kinds of fibers exhibit better modification effects compared with solution-spun fibers. For the small diameter fibers, chemical modification can occur at low treatment temperature, even at 70 °C. X-ray diffraction analysis (XRD) results show that modification not only occurs in the amorphous region of the fibers but also in the crystalline region.

Characterization and use of clays and argillites from the south of Santa Catarina State, Brazil, for the manufacture of clay ceramics

Clay Minerals ◽  
2020 ◽  
Vol 55 (2) ◽  
pp. 172-183
Author(s):  
Alexandre Zaccaron ◽  
Vítor de Souza Nandi ◽  
Marcelo Dal Bó ◽  
Michael Peterson ◽  
Elídio Angioletto ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Laser Diffraction ◽  
Thermal Shrinkage ◽  
Structural Ceramics ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Mountainous Regions ◽  
Sieve Size ◽  
Clay Ceramics

AbstractSix clays from various deposits were studied for their use in the production of structural clay products. The clays were characterized using chemical (X-ray fluorescence), mineralogical (X-ray diffraction) and thermal (differential scanning calorimetry/thermogravimetry) analyses. Particle-size distribution was determined by laser diffraction, plasticity by the Pfefferkorn method and the residue by the sieve-size method. Next, specimens were formed by extrusion and characterized by their linear thermal shrinkage (on drying and firing), water absorption, bulk density, porosity and compressive strength. The clays were, in general, suitable for the manufacture of structural ceramics, mainly bricks. The clays from flooded pits (AV1 and AV2) were classified as floodplain clays and alluvial clays. The clays mined in mountainous regions (AM1 and AM2, as well as AV1) were characterized as siliceous clays due to the abundance of free SiO2 phases.

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