Factors Which Influence Autohesion of Elastomers

1981 ◽  
Vol 54 (1) ◽  
pp. 101-114 ◽  
Author(s):  
C. K. Rhee ◽  
J. C. Andries
Keyword(s):  
Molecular Weight ◽  
Adsorption Mechanism ◽  
Phenolic Resin ◽  
Critical Level ◽  
Formaldehyde Resin ◽  
Rubber Compound ◽  
Structural Requirement ◽  
Polar Groups ◽  
Rubber Compounds ◽  
Black Level

Abstract The following conclusions can be drawn from our studies: (1) An optimum molecular weight (Mn=2095) exists for t-octylphenol-formaldehyde resin to give maximum autohesion to rubber compounds. A critical level of the phenolic resin is required in a given rubber compound to make the tackifying action effective. In addition, the presence of polar groups in a resin molecule is a structural requirement in order for the resin to provide tackiness to rubber compounds. (2) The autohesion of a rubber compound decreases as the loading of processing oil increases from 5 phr to 25 phr. This behavior is independent of the type of oil. (3) The autohesion of a rubber compound decreases with increasing carbon black level, surface area, and structure. (4) Autohesion maximizes at an optimum molecular weight of rubber. (5) Humidity has a pronounced effect on the autohesion of aged SBR compounds, whereas very little effect on that of aged NR compounds. (6) A dual diffusion-adsorption mechanism is operative in autohesion.

scholarly journals A comparison between the properties of low and medium molecular weight phenol formaldehyde resin-treated laminated compreg oil palm wood

2017 ◽  
Vol 19 (3) ◽  
pp. 1-11 ◽  
Author(s):  
G. Aizat ◽  
A. Zaidon ◽  
S. H. Lee ◽  
S. B. Edi ◽  
B. Paiman
Keyword(s):  
Molecular Weight ◽  
Oil Palm ◽  
Phenolic Resin ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Low Molecular Weight ◽  
Hot Press ◽  
Plastic Bag ◽  
Better Than

In order to improve the inherently poor properties of oil palm wood (OPW), this study examines the effects of resin molecular weight, diffusion time and compression ratio on the properties of laminated compreg OPW. Treating solutions used were medium molecular weight phenol formaldehyde (MmwPF) and low molecular weight phenol formaldehyde (LmwPF). OPW strips were soaked in the treating solutions for 24 h before wrapping in a plastic bag and leaving them for diffusion for 2, 4 and 6 days, respectively. Then, three-layer laminated compreg OPW were fabricated and compressed in hot press at 150°C for 20 minutes to achieve compression ratios of 55%, 70% and 80%. Results indicated that dimensional stability and mechanical properties of the phenolic resin treated laminated compreg OPW were significantly better than the untreated laminates. MmwPF-treated laminates exhibited inferior properties in comparison to that of LmwPF-treated laminates. Nevertheless, MmwPF-treated laminated compreg OPW emitted significantly lesser formaldehyde.

scholarly journals Synthesis of Novel Benzoxazines Containing Sulfur and Their Application in Rubber Compounds

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1262
Author(s):  
Acerina Trejo-Machin ◽  
João Paulo Cosas Fernandes ◽  
Laura Puchot ◽  
Suzanne Balko ◽  
Marcel Wirtz ◽  
...  
Keyword(s):  
Phenolic Resin ◽  
Condensation Reaction ◽  
Curing Kinetics ◽  
Structural Features ◽  
Rubber Compound ◽  
Scanning Calorimetry ◽  
Phenolic Resins ◽  
Rubber Compounds ◽  
Mannich Condensation ◽  
13C Nuclear Magnetic Resonance

This work reports the synthesis and successful use of novel benzoxazines as reinforcing resins in polyisoprene rubber compounds. For this purpose, three new dibenzoxazines containing one (4DTP-fa) or two heteroatoms of sulfur (3DPDS-fa and 4DPDS-fa) were synthesized following a Mannich condensation reaction. The structural features of each benzoxazine precursor were characterized by 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and Raman. The new precursors showed well suited reactivity as characterized by differential scanning calorimetry (DSC) and rheology and were incorporated in rubber compounds. After the mixing, the curing profiles, morphologies and mechanical properties of the materials were tested. These results show that the structural feature of each isomer was significantly affecting its behavior during the curing of the rubber compounds. Among the tested benzoxazines, 3DPDS-fa exhibited the best ability to reinforce the rubber compound even compared to common phenolic resin. These results prove the feasibility to reinforce rubber compounds with benzoxazine resins as a possible alternative to replace conventional phenolic resins. This paper provides the first guide to use benzoxazines as reinforcing resins for rubber applications, based on their curing kinetics.

Microscopic versus process parameters in heavy-oil upgrading

1992 ◽  
Vol 50 (1) ◽  
pp. 366-367
Author(s):  
V.A. Munoz ◽  
R.J. Mikula ◽  
C. Payette ◽  
W.W. Lam
Keyword(s):  
Molecular Weight ◽  
Liquid Fuels ◽  
Chemical Components ◽  
Heavy Oils ◽  
Synthetic Fuels ◽  
High Hydrogen ◽  
Optical Texture ◽  
Polar Groups ◽  
Anisotropic Character ◽  
Planar Molecules

The transformation of high molecular weight components present in heavy oils into useable liquid fuels requires their decomposition by means of a variety of processes. The low molecular weight species produced recombine under controlled conditions to generate synthetic fuels. However, an important fraction undergo further recombination into higher molecular weight components, leading to the formation of coke. The optical texture of the coke can be related to its originating components. Those with high sulfur and oxygen content tend to produce cokes with small optical texture or fine mosaic, whereas compounds with relatively high hydrogen content are likely to produce large optical texture or domains. In addition, the structure of the parent chemical components, planar or nonplanar, determines the isotropic or anisotropic character of the coke. Planar molecules have a tendency to align in an approximately parallel arrangement to initiate the formation of the nematic mesophase leading to the formation of anisotropic coke. Nonplanar highly alkylated compounds and/or those rich in polar groups form isotropic coke. The aliphatic branches produce steric hindrance to alignment, whereas the polar groups participate in cross-linking reactions.

THERMOPHYSICAL AND DYNAMIC PROPERTIES OF BUTADIENE-NITRILE RUBBER FILLED WITH ULTRA HIGH-MOLECULAR WEIGHT POLYETHYLENE

2021 ◽  
Vol 0 (2) ◽  
pp. 36-43
Author(s):  
N.V. Shadrinov ◽  
◽  
A.A. Khristoforova ◽  
Keyword(s):  
Molecular Weight ◽  
Dynamic Properties ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Physicomechanical Properties ◽  
Butadiene Rubber ◽  
Rubber Compounds ◽  
Ultrahigh Molecular Weight ◽  
Before And After ◽  
Butadiene Nitrile Rubber ◽  
Ultra High Molecular Weight

The results of the study of the complex of properties of an elastomeric composite material based on nitrile butadiene rubber BNKS-18 and ultrahigh molecular weight polyethylene are presented. The effect of UHMWPE on the vulcanization characteristics of rubber compounds, the physicomechanical properties of vulcanizates before and after thermal aging in a hydrocarbon environment and air, and also on the dynamic properties before and after curing are investigated.

Wire Adhesion Testing

1972 ◽  
Vol 45 (1) ◽  
pp. 16-25 ◽  
Author(s):  
L. C. Coates ◽  
C. Lauer
Keyword(s):  
Bond Strength ◽  
Physical Properties ◽  
Test Method ◽  
Material Strength ◽  
Basic Design ◽  
Rubber Compound ◽  
Reliable Test ◽  
Adhesion Testing ◽  
Rubber Compounds ◽  
The Relationship

Abstract The results of this study are conclusive. The ASTM D-2229 Test Method is not a reliable test for measuring adhesion of wire cords to rubber compounds. However, by using the basic design and modifying it, an accurate measurement of bond strength on a macroscopic level can be obtained. This test is insensitive for all practical purposes to compound physical properties and changes in cord diameter and embedded length—for both stranded and rod-like cords. It is also possible with this test to calculate the amount of stress that is exerted on the surface of the wire cord to determine the relationship between failing stress and the material strength of the rubber compound. Properly used, this new test should give the compounder a better tool to study the adhesion of compounds to metal.

Molecular Structure and Macroscopic Properties of Synthetic Cis-Poly(Isoprene)

1974 ◽  
Vol 47 (2) ◽  
pp. 342-356 ◽  
Author(s):  
V. A. Grechanovskii ◽  
I. Ya Poddubnyi ◽  
L. S. Ivanova
Keyword(s):  
Molecular Weight ◽  
Functional Groups ◽  
Chemical Structure ◽  
Sol Gel ◽  
Average Molecular Weight ◽  
Dense Network ◽  
Green Strength ◽  
Gel Fraction ◽  
Rubber Compounds ◽  
Processing Properties

Abstract By changing the sol-gel ratio and the structure of the gel fraction it is possible to obtain various grades of synthetic cis-poly(isoprene) which show promise for different applications in the tire and mechanical rubber goods industries. The processability of commercial SKI-3 rubber (at a given average molecular weight of sol) depends mainly on the structure of the gel fraction. Thus, for example, inferior processing properties of rubber compounds is associated primarily with the presence of tight gel. The content and structure of the gel fraction also significantly affect plasto-elastic properties of raw rubbers, e.g. a low plasticity of raw rubbers owes to the increased content of gel fraction. The reduced green strength of compounds based on SKI—3 rubber is accounted for by its chemical structure. Conventional methods used to change the properties of rubbers (including the variation in molecular weight, molecular weight distribution, branching degree, and variation in the content and structure of gel fraction) cannot be considered to be adequate to tackle the problem of the green strength of SKI—3 black stocks. The way to solve the problem appears to be the introduction of functional groups into the polymer chain at the stage of synthesis or processing. These functional groups should be active as to the formation of labile rubber—carbon black—rubber and/or rubber—rubber bonds. High purity of microstructure is necessary but not sufficient for obtaining the required level of green strength of compounded SKI—3. The gel fractions of SKI—3 rubber yield vulcanizates with a more dense network than the corresponding sol vulcanizates. The temperature dependence of the tensile strength is controlled by the network density of vulcanizates from high cis-1,4 poly(isoprene).

Oxidation and Ozonation of Rubber

1985 ◽  
Vol 58 (3) ◽  
pp. 637-652 ◽  
Author(s):  
Robert W. Keller
Keyword(s):  
Short Review ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Systematic Development ◽  
Increasing Demand ◽  
Ozone Resistance

Abstract With the wide variety of elastomers, fillers, and other compounding ingredients available today, there is increasing demand for rubber compounds with specific properties. The systematic development of the desired rubber compound can be undermined by the exposure of the compound to oxygen and ozone during use. Thus, a rubber compounder should be aware of the effects of oxygen and ozone attack on rubber and how to compound for oxygen and ozone resistance. This short review is intended as an introduction to the phenomena of oxidation and ozonation of rubber.

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.

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