Preparation and Properties of Rubberlike High Polymers. IV. Correlation between Structure and Properties of Elastomers Derived from Dienes

1948 ◽  
Vol 21 (2) ◽  
pp. 377-397
Author(s):  
G. Salomon ◽  
C. Koningsberger
Keyword(s):  
Natural Rubber ◽  
Elevated Temperatures ◽  
Elastic Recovery ◽  
Chain Structure ◽  
Complex Compounds ◽  
Structure And Properties ◽  
Straight Chain ◽  
Gutta Percha ◽  
Brittle Point ◽  
Derivatives Of

Abstract The correlation between structure and properties of elastomers prepared from dienes, natural rubber, gutta-percha, as well as those of some significant derivatives of natural rubber, are discussed. The similar influence exerted by methyl groups on the brittle point, elastic recovery, and permeability to gases is demonstrated and separated from the effect caused by insertion of —CH2— CHR— groups in straight-chain polybutadiene, which takes place during co-polymerization or 1,2 addition. The preponderant influence of an unbranched-chain structure on tensile strength at elevated temperatures and in the swollen state is illustrated. Complex compounds with silver nitrate provide further evidence for the particular symmetry of the natural rubber chain: They are reinforcing agents for synthetic elastomers. The brittle points of hydrochlorides from natural rubber, gutta-percha, and polyisoprene are compared with those of polyvinyl compounds. Correlation between the structure of molecular units in a polymeric paraffin derivative and its elasticity is pointed out.

scholarly journals SYNTHESIS, STRUCTURE AND PROPERTIES OF COMPLEX COMPOUNDSOF COBALT (II) WITH BENZOXASINE DERIVATIVES

2020 ◽  
Vol 1 (30(57)) ◽  
pp. 75-78
Author(s):  
Medina Humaidovna Shamsutdinova ◽  
Nur-Magomed Rezvanovich Tashligov ◽  
Yunus Yakubovich Kurbanov
Keyword(s):  
Ir Spectroscopy ◽  
Coordination Compounds ◽  
Chemical Method ◽  
Complex Compounds ◽  
Spectroscopy Data ◽  
Structure And Properties ◽  
Composition Structure ◽  
Work Coordination ◽  
Derivatives Of ◽  
Azomethine Fragment

In this work, coordination compounds of Co (II) with derivatives of dihydro-4H-3,1-benzoxazines were synthesized by a chemical method and their composition, structure, and physicochemical properties were studied. ... According to the data of elemental analysis and analysis for metal, the obtained complex compounds have the composition ML2, where M is metal, L are ligands: 2- [2-hydroxyphenyl] -4,4-diphenyl-1,2-dihydro-4H-3,1benzoxazine (L1), 2- [2-hydroxy-5-nitrophenyl] -4,4-diphenyl-1 , 2-dihydro-4H-3,1-benzoxazine (L2), 2- [2hydroxynaphthyl] -4,4-diphenyl-1,2-dihydro-4H-3,1-benzoxazine (L3), 2- [ 2-hydroxynaphthyl] -4,4-diethyl-1,2dihydro-4H-3,1-benzoxazine (L4). The structure and properties of the obtained complex compounds were studied by IR spectroscopy. According to IR spectroscopy data, it was found that in all complex compounds, the ligand participates in the open azomethine form; coordination with the metal atom involves two oxygen atoms and a nitrogen atom of the azomethine fragment of the ligand. It was found that the ligand in the complex performs a tridentate chelate-bridging function. The structure of complex compounds of cobalt with derivatives of benzoxazines is proposed.

Characterization of the trans-structure in the molecular chain structure of natural rubber

2021 ◽  
pp. 131209
Author(s):  
Zechun Li ◽  
Changjin Yang ◽  
Yanchan Wei ◽  
Yuanbing Zhou ◽  
Shuangquan Liao
Keyword(s):  
Natural Rubber ◽  
Chain Structure ◽  
Molecular Chain ◽  
Trans Structure

Noncontacting Vibration Measurement Using a Massless Interferometric Accelerometer

1995 ◽  
Author(s):  
Keyu Li
Keyword(s):  
Elevated Temperatures ◽  
Laser Light ◽  
Vibration Measurement ◽  
Object Surface ◽  
Out Of Plane ◽  
Plates And Shells ◽  
Fringe Patterns ◽  
Hostile Environments ◽  
Derivatives Of ◽  
Object Behavior

Abstract An interferometric strain measurement technique is extended to vibration measurements. The technique is based on two micro-indentations placed on an object surface using a combination of diffraction and interference of laser light. Relative displacements between the two indentations and derivatives of in-plane and out-of-plane vibrational displacements are measured by analyzing the phase shift of the interference fringe patterns. The technique can be used to study bending stress and deflection problems in vibrational beams, plates and shells. The displacement derivatives are measured in real time, from which time derivatives or the velocity and acceleration of the displacement derivative as well as vibrational frequency can be determined. The technique has advantages over an accelerometer in that it is noncontacting and does not require attachment of the transducer to the object which could alter the object behavior. In addition, it has many desirable features such as being extremely compact, massless, and applicable to hostile environments such as those associated with production and elevated temperatures.

Bonding

1938 ◽  
Vol 11 (1) ◽  
pp. 169-186
Author(s):  
B. J. Habgood
Keyword(s):  
Natural Rubber ◽  
New Method ◽  
Bonding Agent ◽  
Butadiene Rubber ◽  
High Concentration ◽  
Chloro Derivatives ◽  
Brass Plating ◽  
Derivatives Of

Abstract 1. Neoprene and rubber can be bonded directly, provided that: (a) the composition of the two stocks are balanced; (b) the stocks are kept warm; (c) bonding is carried out with the minimum of delay. 2. Neoprene and rubber can be bonded by other methods which give greater latitude of working: (a) by the use of a high concentration of accelerator at the interface; (b) by the use of a tie-gum mix made from butadiene rubber (preferably sodium-polymerized); (c) by the use of mixtures of Neoprene, chloro derivatives of rubber, either alone or admixed with rubber. Partially hydrochlorinated rubber is particularly useful in this direction. 3. Synthetic rubbers can be bonded one to another or to natural rubber either directly or through the medium of sodium-butadiene rubber. 4. The bonding of rubber to metal has been considered and the main methods discussed, including bonding by means of ebonite; alloys, particularly brass; cyclorubbers, Thermoprenes, and cements. 5. The bonding of synthetic rubbers to metals has been examined and a new method of bonding Neoprene to a variety of metals, including iron, steel, aluminum, zinc, and lead, has been worked out, using a solution of chlorinated rubber as bonding agent. 6. By combining the various methods described in this paper, rubber may be bonded to metals such as aluminum without brass plating.

INTERMETALLIC COMPOUND AlxTi – ARE PROMISING MATERIAL FOR HIGH ELEVATED TEMPERATURES (review) Part 1. The crystaline structure and properties of the intermetallic compound Al2Ti

2021 ◽  
pp. 28-43
Author(s):  
N.A. Nochovnaya ◽  
◽  
V.I. Ivanov ◽  
L.Yu. Avilochev ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compound ◽  
Lamellar Structure ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Texture Formation ◽  
Structure And Properties ◽  
High Temperature Alloys ◽  
Transformation Mechanisms ◽  
Increased Strength

The Al2Ti intermetallic compound is the most promising base for high-temperature alloys designed for advanced power plants. This work provides an overview of the structures of binary alloys concerning to the Ti–Al system, as well as the phase transformation mechanisms and the peculiarities of plastic deformation of alloys. The alloys which phase composition is represented by a mixture of r-Al2Ti+γ-TiAl with a lamellar structure show anomalous mechanical properties depending on texture formation and grain size. These alloys possess increased strength and decreased plasticity at elevated temperatures.

Effect of vulcanization time on crosslink density and aging performance of natural rubber composites

2020 ◽  
Vol 62 (8) ◽  
pp. 858-862
Author(s):  
Ece Unur Yilmaz ◽  
Ahu Kor Dayioglu ◽  
Seda Balaban
Keyword(s):  
Natural Rubber ◽  
Crosslink Density ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Operating Conditions ◽  
Rubber Composites ◽  
Rubber Mixture ◽  
Natural Rubber Composites ◽  
Different Temperatures ◽  
Auto Parts

Abstract Natural rubber composites are widely used in the automotive industry because of their improved viscoelastic characteristics that are mostly governed by crosslink density. However, rubber parts suffer deterioration of performance over long service lives. Therefore, optimization of crosslink density and prediction of changes in physico-mechanical properties over time at elevated temperatures is extremely important for the production of safe auto parts. In this work, the effect of vulcanization time on crosslink density and thus the performance and lifetime of natural rubberbased auto parts was investigated. The natural rubber mixture prepared in this context was vulcanized for 3, 5, 10 and 15 minutes at a constant temperature of 160 °C. The crosslink density of each vulcanizite was determined by equilibrium swelling tests and the Flory-Rehner equation. The maximum crosslink density (10.75 × 10-5 mol × cm-3) and the minimum permanent compression set values (10 % at 70 °C and 25 % at 100 °C) were recorded for the sample vulcanized for 10 minutes (v10). Aging behavior of the samples were investigated by stress relaxation tests performed at 85 °C, 100 °C and 120 °C. The service lives of the vulcanizites at different temperatures were predicted by linear Arrhenius fits of degradation times. The sample vulcanized for 10 minutes (v10) was shown to exhibit a service life of 2282 hours at 70 °C in air and the optimum physico-mechanical performance under real operating conditions. The performance and lifetime prediction procedure used in this work could be employed in an early design of rubber components for specific applications.

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