Research of Polyethylene in Products of Autocomponents

2019 ◽  
Vol 946 ◽  
pp. 103-108
Author(s):  
Lenar N. Shafigullin ◽  
Natalia V. Romanova ◽  
Azat T. Gabdrakhmanov
Keyword(s):  
Melting Point ◽  
Quality Assessment ◽  
Automotive Industry ◽  
Complex Geometry ◽  
Performance Characteristics ◽  
Degree Of Crystallinity ◽  
Dsc Analysis ◽  
Modifying Additives ◽  
The Difference ◽  
The Degree Of Crystallinity

Polyethylene is widely used in the production of products for the automotive industry, due to the unique properties and the possibility of manufacturing hollow products of complex geometry. In this work the thermal research of polyethylene in finished productsand the quality assessment of autocomponents materials, depending on the type of polyethylene were conducted. An assessment methodologyof the material of products is suggested, which indicates the difference between the batches of autocomponents products for the acceptance or rejection thisbatch by conducting DSC-analysis. It was found that the products of autocomponents, in particular, "splash-absorbing shield", based on LDPE with a melting point above 110 °C have unsatisfactory performance characteristics. It is shown that modifying additives to improve the elasticity of the LDPE lead to partial the amorphization of PE, that is, a decrease in the degree of crystallinity by 4% relative to the LDPE without additives.

Thermal Crystallization of Polytetrahydrofuran Networks

1991 ◽  
Vol 64 (1) ◽  
pp. 74-82 ◽  
Author(s):  
C. Michael Roland ◽  
Gary S. Buckley
Keyword(s):  
Melting Point ◽  
Crystallization Behavior ◽  
Degree Of Crystallinity ◽  
Melting Point Depression ◽  
Network Architectures ◽  
Experimental Conditions ◽  
Thermal Crystallization ◽  
Melting Temperatures ◽  
Equilibrium Melting Point ◽  
The Degree Of Crystallinity

Abstract The formation of a network in PTHF inhibits the crystallization of chain units in proximity to the crosslinks. From melting-point-depression measurements, it is estimated that the suppression in crystallizability extends to as much as 8 chain units away from a network junction. This estimate is consistent with the degree of crystallinity measured in various crosslinked PTHF rubbers. The equilibrium melting point for linear PTHF was determined to be 361°K. Although this is significantly higher than previously reported values, the present result is congruent with the melting temperatures measured for crosslinked PTHF, and its use leads to satisfactory predictions of their melting-point depression. The distribution in the lengths of network chains exerted a trivial influence on thermal crystallization behavior. Although this distribution must in principle influence crystallization behavior in so far as it governs crystallizable sequence lengths, differences between uni- and bi-modal network architectures were moderate under the present experimental conditions.

scholarly journals Estimation of the Age of Architectural Heritage Objects by Microstructural Changes of Calcite in Lime Mortars of Ancient Brickwork and Masonry

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 240
Author(s):  
Vladimir Kotlyar ◽  
Victoria Pishchulina ◽  
Alexey N. Beskopylny ◽  
Besarion Meskhi ◽  
Yury Popov ◽  
...  
Keyword(s):  
18Th Century ◽  
Degree Of Crystallinity ◽  
Architectural Heritage ◽  
Natural Conditions ◽  
Relative Age ◽  
Lime Mortars ◽  
Powder Samples ◽  
Diffraction Patterns ◽  
Cultural Monuments ◽  
The Degree Of Crystallinity

Determining the age of ancient architectural and cultural monuments is a significant scientific problem. An approach based on the transformation of portlandite into calcite and subsequent recrystallization of calcite is considered, which allows for estimating the relative age of ancient brickworks for local groups of historic buildings based on the results of diffraction studies of powder samples of carbonate mortars and measurements of samples with a known age. This article presents the results of the study of lime mortars of ancient brickwork. Under natural conditions, the process of transformation of portlandite into calcite takes from 100 to 200 years. The rate of this process is influenced by temperature, humidity, peculiarities of interaction with carbon dioxide contained in the air, etc. Examples show that portlandite is completely transformed into calcite in masonry mortars of the 18th century and that portlandite is not found in older mortars. It was determined that after the transformation of portlandite into calcite, an increase in the degree of recrystallization of calcite is observed, which manifests itself in powder diffraction patterns in the relative broadening of the diffraction peak of calcite hkl 104. In a detailed study, an estimate of the peak width at half maximum (FWHM) associated with the degree of crystallinity is effective. The actual data are given, which show that in older lime mortars the degree of recrystallization of calcite is higher than in younger ones. This fact makes it possible to indirectly determine the relative age of brickwork and masonry of various buildings of architectural heritage, which is especially relevant for the objects with the use of lime mortars of the northern provinces of the Byzantine Oecumene and other periods of various cultures.

scholarly journals Preparation and Characterization of Talc Filled Thermoplastic Polyurethane/Polypropylene Blends

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Emi Govorčin Bajsić ◽  
Vesna Rek ◽  
Ivana Ćosić
Keyword(s):  
Thermal Properties ◽  
Thermoplastic Polyurethane ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polypropylene Blends ◽  
Pp Blends ◽  
The Degree Of Crystallinity ◽  
Better Than

The effect of the addition of talc on the morphology and thermal properties of blends of thermoplastic polyurethane (TPU) and polypropylene (PP) was investigated. The blends of TPU and PP are incompatible because of large differences in polarities between the nonpolar crystalline PP and polar TPU and high interfacial tensions. The interaction between TPU and PP can be improved by using talc as reinforcing filler. The morphology was observed by means of scanning electron microscopy (SEM). The thermal properties of the neat polymers and unfilled and talc filled TPU/PP blends were studied by using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The addition of talc in TPU/PP blends improved miscibility in all investigated TPU/T/PP blends. The DSC results for talc filled TPU/PP blends show that the degree of crystallinity increased, which is due to the nucleating effect induced by talc particles. The reason for the increased storage modulus of blends with the incorporation of talc is due to the improved interface between polymers and filler. According to TGA results, the addition of talc enhanced thermal stability. The homogeneity of the talc filled TPU/PP blends is better than unfilled TPU/PP blends.

The Influence of the Degree of Crystallinity on the Glass Transition Temperature of Polymers

2013 ◽  
Vol 864-867 ◽  
pp. 751-754 ◽  
Author(s):  
Andrey Askadskii ◽  
Marina Popova ◽  
Tatyana Matseevich ◽  
Elena Kurskaya
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Degree Of Crystallinity ◽  
Low Degrees ◽  
The Degree Of Crystallinity

The influence of the degree of crystallinity of polymers on the glass transition temperature Tg of their amorphous domains is quantitatively analyzed. The analysis is made based on the Mandelkerns ideas [ concerning the restrictive effect of crystallization on the mobility of macromolecules within the amorphous domains. At low degrees of crystallinity, Tg of amorphous domains slowly increases, and then increases much faster at high degrees of crystallinity.

Electrical Discharge Grinding (EDG) of Polycrystalline Diamond - Effect of Machining Polarity

2014 ◽  
Vol 1025-1026 ◽  
pp. 628-632 ◽  
Author(s):  
Mohammad Zulafif Rahim ◽  
Song Lin Ding ◽  
John Mo
Keyword(s):  
Electrical Discharge ◽  
Complex Geometry ◽  
Polycrystalline Diamond ◽  
Machining Process ◽  
Morphological Examination ◽  
Carbon Structure ◽  
Finishing Process ◽  
Advanced Machining ◽  
The Difference ◽  
Pcd Tools

Electrical discharge grinding (EDG) is an advanced machining process and can be utilised to fabricate complex geometry of PCD tools. However, the PCD removal mechanism in this process is complicated. This study was carried out to understand the difference in PCD surface structure with difference EDG polarities. The study revealed that the finishing process with negative polarity is the reason for the porous structure on the surface. Further analysis on the chemical element and carbon structure were implemented as the morphological examination of the surface.

Post-irradiation effects on gamma-irradiated nylon 6,12 fibers

2013 ◽  
Vol 33 (9) ◽  
pp. 823-828 ◽  
Author(s):  
Carmina Menchaca-Campos ◽  
Gonzalo Martínez-Barrera ◽  
Héctor López-Valdivia ◽  
Héctor Carrasco ◽  
Alberto Álvarez-Castillo
Keyword(s):  
Melting Point ◽  
Storage Time ◽  
Chain Scission ◽  
Degree Of Crystallinity ◽  
Irradiation Effects ◽  
Post Irradiation ◽  
Degradation Temperature ◽  
Optical Images ◽  
Gamma Irradiated ◽  
Irradiation Process

Abstract Post-irradiation effects on nylon 6,12 crystalline fibers gamma-irradiated 6 years previously (6YI) were studied, including thermal stability and morphology; their relationship with storage time was also studied. The results of these studies were compared with those obtained for non-irradiated (NI) and namely freshly irradiated (FI) crystalline fibers. The results include analyses like thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM) and optical images for (6YI and FI) both kinds of nylon 6,12 fibers. The results showed that the most prominent effect is related to the reaction progress. The chain scission and/or crosslinking mechanisms, as well as the free radicals, allow proceeding with the reaction, and consequently, changes on the properties of the FI samples. The melting point, degree of crystallinity, degradation temperature and morphology prove that additional chemical reactions and surface modifications keep occurring in the fibers long after the irradiation process has ended. With storage time, the surface becomes rougher, the color turns yellowish, the melting point diminishes and the degree of crystallinity increases.

Study of the Activated Charcoal Structure from Water Hyacinth Based on Carbonization Temperature Variations and Activators

2021 ◽  
Vol 1028 ◽  
pp. 326-330
Author(s):  
Otong Nurhilal ◽  
Sahrul Hidayat ◽  
Dadan Sumiarsa ◽  
Maykel Manawan ◽  
Risdiana
Keyword(s):  
Carbon Material ◽  
Activated Charcoal ◽  
Water Hyacinth ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Lithium Sulfur Batteries ◽  
Amorphous Structures ◽  
Degree Of Graphitization ◽  
The Degree Of Crystallinity

The quality of the carbon material for application of electrodes in the battery is indicated by its ability to intercalate ions, atoms or molecules. Graphite is a carbon material with good intercalation capability. In this research, a carbon material in the form of activated charcoal produced from biomass of water hyacinth has been prepared, which is carbonized at various temperatures of 400, 500, and 600 °C with three different activators of ZnCl2, KOH and H3PO4. The activated charcoal will be used as a cathode composite in lithium sulfur batteries. To determine the quality of the activated charcoal, the structure properties of activated charcoal were characterized using X-ray diffraction (XRD). Several parameters that are determined from XRD data included the degree of crystallinity, and the degree of graphitization (Y). The degree of crystallinity was found in the ranges between 5.56 and 12.6%, where activated charcoal was dominated by amorphous structures. The value of the degree of graphitization was about 36%.

Study of structural and morphological changes during acсelerated oxidative degradation of mixtures of polyoxybutyrate with polycaprolactane

2021 ◽  
Vol 5 ◽  
pp. 60-69
Author(s):  
V. N. Vasilets ◽  
◽  
A. P. Pankina ◽  
E. A. Nemets ◽  
V. Yu. Belov ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Oxidative Degradation ◽  
Initial Mixture ◽  
Polymer Composite Material ◽  
Degree Of Crystallinity ◽  
Fenton Reagent ◽  
Dsc Method ◽  
The Degree Of Crystallinity ◽  
Composite Samples ◽  
Scanning Electron

Structural and morphological changes in the films of poly(oxybirutyrate-co-oxyvalerate) (P(OB-OV)) with poly-e-caprolactone (PCL) were studied by IR spectroscopy, DSC, and scanning electron microscopy during accelerated oxidative degradation under tests in Fenton reagent. It is shown by the DSC method that the phase separation of the P(OB-OV) and PCL components is observed in the initial mixture. The melting of various phases of P(OB-OV) is observed at temperatures of 147 °C and 157 °C, and PCL melts at a temperature of 61 °C. The degree of crystallinity of P(OB-OV) and PCL in the mixture is 67 % and 50 %, respectively. It was found that the degradation of poly(oxybirutyrate-co-oxyvalerate) prevails during incubation of composite samples in Fenton solution for 2 to 12 weeks. By changing the ratio of the components, it is possible to significantly change the rate of oxidative degradation, the molecular weight and the degree of crystallinity of the polymer composite material P(OB-OV):PCL.

Preparation of Chitin Whisker and Effect to Crystallization of Polylactide

2018 ◽  
Vol 773 ◽  
pp. 82-87
Author(s):  
Nichaphat Passornraprasit ◽  
Wanpen Tachaboonyakiat
Keyword(s):  
Phase Separation ◽  
Transition Temperature ◽  
Nanocomposite Films ◽  
Degree Of Crystallinity ◽  
Thermal Transition ◽  
Hydrolysis Time ◽  
Film Extrusion ◽  
Agglomeration Of Nanoparticles ◽  
Acidolysis Reaction ◽  
The Degree Of Crystallinity

The aim of this study was to investigate the effect of chitin whisker (CW) to the crystallization of polylactide (PLA) nanocomposite films. CW which obtained from acidolysis reaction was compounded with PLA pellets into nanocomposite films by cast film extrusion. The morphology and crystallinity of CW were observed by TEM and XRD, illustrated that the dimension of whisker was affected by hydrolysis time. Increasing of hydrolysis time, the length of whisker was more regular with narrower distribution. Moreover, the crystallinity of whisker was obviously increased after acid hydrolysis. The nanocomposite film showed rough surface compared to pure PLA film due to some agglomeration of nanoparticles. However, CW and PLA were well-mixed with no phase separation. The introduction of 0.1 phr of CW decrease cold-crystallization temperature (Tcc) from about 121 °C to 118 °C and also increase the degree of crystallinity around 10%. There was no difference of thermal transition temperature between pure PLA and nanocomposite films with the addition of CW more than 0.1 phr which inspected by DSC. Despite the transition temperature express insignificantly different, the degree of crystallinity of nanocomposite was increase, indicating that chitin whisker would induce the crystallinity of PLA.

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