Study of the Thermal Oxidation of Butadiene-Nitrile Elastomers

1956 ◽  
Vol 29 (2) ◽  
pp. 607-611
Author(s):  
A. S. Kuzminskii˘ ◽  
E. B. Popova
Keyword(s):  
Mechanical Properties ◽  
Thermal Oxidation ◽  
Structure Formation ◽  
Physical And Mechanical Properties ◽  
Rate Of Change ◽  
Essential Difference ◽  
Equilibrium Modulus ◽  
Nitrile Rubbers ◽  
Dominant Process ◽  
The One

Abstract 1. Processes of destruction and structure formation take place during the thermal oxidation of butadiene-nitrile rubbers. These processes take place simultaneously, and are the result of absorption of oxygen by the rubber molecules. The dominant process, which governs the changes in the physical and mechanical properties of rubber, is structure formation. 2. An essential difference between the behavior of vulcanizates of SKN-18 on the one hand, and of SKX-26 and SKN-40 on the other, is shown by heat oxidation and aging. Depending on the length of the induction period of oxidation inhibited by phenyl-2-naphthylamine, the nature of the consumption of inhibitor, and the rate of change of the equilibrium modulus, relaxation constant, and standard physical-mechanical properties during aging, the behavior of SKN-18 is practically the same as that of other butadiene polymers containing an equal number of double bonds in the main chains of the molecules. 3. It was established that, during thermal oxidation of butadiene-nitrile copolymers, acrylonitrile chains of the rubber molecules undergo conversion. 4. The formation of a certain quantity of substances soluble in methyl and ethyl alcohol during oxidation of nitrile rubbers is revealed, and it is established that substances present in these byproducts can inhibit the oxidation of rubber. 5. The resistance of butadiene-nitrile rubbers to thermal inhibited oxidation and aging of vulcanizates, which is greater than that of other butadiene rubbers, is explained by the formation from the rubber itself, during oxidation, of substances which are, in combination with phenyl-2-naphthylamine, very strong inhibitors of the oxidation process.

Resin-Wood Particulate Composite Reinforced with Piassava Fibre

2015 ◽  
Vol 1088 ◽  
pp. 415-418
Author(s):  
André Luis Christoforo ◽  
Francisco Antonio Rocco Lahr ◽  
Cristiane Inácio de Campos ◽  
Elen Aparecida Martines Morales ◽  
Juliana Cortez Barbosa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Hybrid Composite ◽  
Mass Fraction ◽  
Physical And Mechanical Properties ◽  
Particulate Composite ◽  
Modulus Of Rupture ◽  
Casting Method ◽  
Wood Sawdust ◽  
The One

These research objectives the development and evaluation of physical and mechanical properties of a hybrid composite manufactured epoxy resin reinforced by Eucalipto sp. wood sawdust and treated piassava fibers. The evaluated properties were modulus of elasticity (MOE) and modulus of rupture (MOR) in static bending, water absorption after 24 hours, porosity and apparent density. Three factors with two levels was evaluated: thickness (3 mm and 4 mm), volumetric resin fraction (45% and 50%) and the use or not of laminate piassava fibers reinforcement, leading to a factorial design of 23 type. Were manufactured four panels, two with 50% and two with 55% of resin, using casting method. For the physical and mechanical properties obtained, the better conditions were the one that uses 50% of epoxy resin, 55% sawdust mass fraction and with the use of laminated piassava fibers reinforcement. The thickness was not statistically significant in obtaining the properties evaluated.

The Study of Structure Formation Evolution at High Pressure with a Shear in a Corrosion-Resistant Austenitic-Ferritic Steel 03Kh14N10K5M2YuT with Different Initial States

2020 ◽  
Vol 299 ◽  
pp. 600-605
Author(s):  
Tatyana V. Mal’tseva ◽  
Anna V. Levina ◽  
Ekaterina K. Skobelina
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Phase Transformations ◽  
Structure Formation ◽  
Ferritic Steel ◽  
Physical And Mechanical Properties ◽  
Submicrocrystalline Structure ◽  
Plastic Deformations ◽  
Corrosion Resistant ◽  
Initial States

The article presents results of studies of phase transformations and structure formation that form the necessary complex of physical and mechanical properties of austenitic-ferritic steel with a structural ratio of 50:50. The structure formation at high pressure with a shear of steel 03Kh14N10K5M2YuT with different initial states is studied. After the action of intense plastic deformations, a submicrocrystalline structure arises. This causes interest in these deformations.

Physical and Mechanical Properties of the Amorphous and Nanocrystalline Alloys

2018 ◽  
Vol 382 ◽  
pp. 53-57 ◽  
Author(s):  
Vladimir Tsepelev ◽  
Yuri Starodubtsev ◽  
Kai Ming Wu ◽  
Nadezhda Tsepeleva ◽  
Boris Semenov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Structure Formation ◽  
Chemical Elements ◽  
Physical And Mechanical Properties ◽  
Amorphous Structure ◽  
Nanocrystalline Alloys ◽  
Soft Magnetic ◽  
Complex Process ◽  
Nanocrystalline Ribbon

An amoprphous and nanocrystalline ribbon is produced applying the technology of rapid molten metal quenching. The chemical composition of the alloy is required to contain elements ensuring the amorphous structure formation in the course of quenching. A great number of various chemical elements in amorphous and nanocrystalline alloys contribute to the complex process of the structure formation in the course of heat treatment of the amorphous precursor. After heat treatment, the structure of the soft magnetic material can remain amorphous or partially crystallized or nanocrystalline. The results of an investigation into the melts’ property of iron-based amorphous and nanocrystalline alloys are presented in the paper. The structure has been shown to influence mechanical properties of the material in preparing the melt before casting.

Blown Film of m-LLDPE Using a Novel Eccentric Rotor Extruder

2018 ◽  
Vol 783 ◽  
pp. 28-33
Author(s):  
He Zhi He ◽  
Shi Ming Liu ◽  
Lan Ya Cheng ◽  
Yi Ping Ni ◽  
Feng Xue ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Physical And Mechanical Properties ◽  
Elongational Flow ◽  
Screw Extruder ◽  
Novel Device ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Eccentric Rotor ◽  
The One

Metallocene linear low-density polyethylene (m-LLDPE) has superior physical and mechanical properties. While, the film blowing processability of m-LLDPE was very poor when processed under shear flow. To overcome this drawback, a novel device based on elongational flow was self-developed to process m-LLDPE. In order to investigate the effect of elongational flow on the processability improvement of m-LLDPE, five types PE were studied in this paper. All kinds of PE were prepared using this novel device and traditional single-screw extruder with molecular weight and its distribution, mechanical properties and WAXD characterization. Gel Pemeation Chromotographer (GPC) data shows that molecular weight of each resin prepared using this novel eccentric rotor extruder (ERE) is higher than that processed by traditional single screw extruder (SSE). Mechanical properties showed that tensile properties of all kinds of films blowing from ERE is better than the one from SSE. However, tear properties of m-LLDPE films made from ERE differ from LDPE or LLDPE. And had a relative low value than the one made from SSE. In addition, Wide-angle X-ray Diffraction (WAXD) results indicate that films blowing from ERE exist a partially ordered component in addition to the usual crystalline and amorphous components which can’t be achieved from SSE.

Progress in adapting the Investment Casting of NiAl

1998 ◽  
Vol 552 ◽  
Author(s):  
F. Scheppe ◽  
H. Rothe ◽  
P. R. Sahm
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Gas Turbine ◽  
Scale Up ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
High Melting ◽  
High Melting Point ◽  
Shell Mold ◽  
The One

ABSTRACTNiAl alloys offer significant advantages as structral materials in gas turbine applications due to a unique range of physical and mechanical properties. The high melting point and low RT plasticity of NiAl alloys present special problems for mold materials. Typical shell molds for advanced superalloys are very close to there application limits. On the one hand it is necessary to keep the SiO2 level as low as possible, but on the other hand the mold has to be strong enough for the cast process and weak enough to allow for the contraction of the metal during the solidification. The result of this research is the application of a SiO2 shell mold for a heat shield. To scale up these results to production and quantities will be the further work.

scholarly journals INFLUENCE OF FINE-DISPERSED ADDITIVE FROM CONCRETE SCRAP ON STRUCTURE FORMATION OF PORTLANDCEMENT

2021 ◽  
Vol 6 (1) ◽  
pp. 20-28
Author(s):  
A. Ahmed ◽  
R. Lesovik ◽  
W. Al'-Bo-Ali ◽  
G. Lesovik
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Structure Formation ◽  
Physical And Mechanical Properties ◽  
High Dispersion ◽  
Optimal Density ◽  
Building Products ◽  
X Ray ◽  
Mineral Additive ◽  
Mineral Additives

The object of the study is the effect of the introduction of a mineral additive (Ssp = 900 m2/kg) of the fraction (0.315–5 m) of the screening out of crushing concrete scrap into Portland cement for the production of various building products and structures. A fraction of concrete scrap of 0.315–5 mm is used in the work, since the X-ray phase analysis of various fractions of concrete scrap shows that these fractions have a rational content of non-hydrated particles of C3S and C2S. It is proved that the use of finely ground concrete scrap (Ssp = 900 m2/kg) as a mineral additive in Portland cement increaseINFLUENCE OF FINE-DISPERSED ADDITIVE FROM CONCRETE SCRAP ON STRUCTURE FORMATION OF PORTLANDCEMENT s the physical and mechanical properties of concrete. Comparative physical and mechanical indicators of the hardening of composite binders indicate that the most stable results with a uniform increase in strength is a composition with 5 % mineral additive, with an increase in strength from 2 to 7 days by 36 % and from 7 to 28 days by 46 %. It is found that the most rational are the compositions with 5 % and 10 % mineral additives providing an increase in the strength of the samples by 16% compared to the control composition. Due to the high dispersion, the mineral additive from concrete scrap acts as additional crystallization centers during the hydration of Portland cement, which leads to the creation of a skeleton coral-like structure, which additionally overgrows with submicroscopic crystals. With a specific surface area of 900 m2/kg, the best conditions are created for the formation of the primary frame and its further overgrowth with various crystalline calcium hydrates, which provide optimal density and strength.

Effects of calcium leaching on the physical and mechanical properties of aerial lime-cement mortars

2019 ◽  
Vol 17 (3) ◽  
pp. 649-666
Author(s):  
Soufyane Bellifa ◽  
Nadir Boumechra
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Hydroxide ◽  
Nitrate Solution ◽  
Physical And Mechanical Properties ◽  
Rate Of Change ◽  
Content Type ◽  
Calcium Leaching ◽  
Ammonium Nitrate Solution ◽  
Cement Mortars

Purpose This paper aims to assess the effects of chemically accelerated leaching on the physical and mechanical properties of aerial lime–cement mortars (LCMs). Design/methodology/approach Two aerial LCMs, differencing mainly in their calcium hydroxide content, were degraded by the use of an ammonium nitrate solution as a leaching agent. The leaching effects were studied by evaluating the rate of change in physical (sorptivity and mass loss) and mechanical (flexural and compressive strength) characteristics of aerial LCMs. To quantify the evolution and kinetics of degradation, the leached depth was then characterized at different levels of degradation by means of a phenolphthalein solution. Findings The experimental results showed that the dissolution of binder decreases the mass, alkalinity and strength of aerial LCMs but increases their sorptivity. A linear relationship was derived by plotting the values of leached depth against the square root of immersion time in an aggressive solution. It was found that the leached depth followed diffusion-controlled kinetics. Originality/value It was found that the global loss of compressive strength of aerial LCMs because of complete dissolution of calcium hydroxide can reach up to 80 per cent.

Changes of the Mechanical Properties of Vulcanizates during the Early Stages of Thermal Oxidation

1952 ◽  
Vol 25 (4) ◽  
pp. 801-807 ◽  
Author(s):  
A. S. Kuzminskiĭ ◽  
L. I. Lyubchanskaya
Keyword(s):  
Mechanical Properties ◽  
Induction Period ◽  
Thermal Oxidation ◽  
Strong Influence ◽  
Thermal Structure ◽  
Work Capacity ◽  
Rate Of Change ◽  
Early Stages ◽  
Oxidation Degradation ◽  
Autocatalytic Oxidation

Abstract 1. The structural-mechanical properties of vulcanizates of various rubbers during the time of the induction period and during autocatalytic oxidation were studied. 2. A change of the mechanical properties of vulcanizates in the induction period is a consequence of oxidation (degradation and polymerization) and thermal structure formation, taking place with the participation of the double bonds of the side chains. 3. In complete accord with the theory, at the end of the induction period and in the early stages of autocatalysis, the physical-mechanical properties of vulcanizates change sharply; as a result of this, the vulcanizates lose their technical value. 4. During the heat aging of rubber, the concentration of inhibitor within the range of 0.25–0.5 per cent has no effect on the rate of change of the physical-mechanical properties of vulcanizates, but has a strong influence on the work capacity of the latter.

scholarly journals Analysis of research on soil destruction criteria during its interaction with working bodies

2021 ◽  
Vol 285 ◽  
pp. 07003
Author(s):  
Vladimir I. Konovalov
Keyword(s):  
Mechanical Properties ◽  
Soil Layer ◽  
Physical And Mechanical Properties ◽  
Rate Of Change ◽  
Point Of View ◽  
Stress Theory ◽  
Functional Relationships ◽  
Working Surface ◽  
Soil Destruction ◽  
Working Bodies

Under the action of the working surface of the tillage unit, three mutually perpendicular stresses and corresponding deformations occur in the soil layer, which are characterized by different time functions. The finding of these functional relationships is the fundamental task of agricultural mechanics, with the help of which the process of soil crumbling with different physical and mechanical properties can be described in interaction with working bodies. The article presents an analysis of the results of studies of domestic and foreign scientists of the process of soil destruction in its interaction with working bodies. When considering the process of soil destruction from the point of view of stress theory, the Coulomb-Mohr theory of destruction is most often used. It is proposed to expand the consideration of the process of soil destruction by adding elements to the theory of strength that will describe the rate of change of the acting loads.

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