The use of epoxy resins in synthetic rubber compositions

Thomas F. Mika

doi:10.1002/jctb.5010060901

Carboxylic Rubbers from Scrap Vulcanized Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3542715 ◽

1957 ◽

Vol 30 (2) ◽

pp. 689-704

Author(s):

Joseph Green ◽

E. F. Sverdrup

Keyword(s):

Maleic Anhydride ◽

Epoxy Resins ◽

Unsaturated Compound ◽

Low Cost ◽

Critical Concentration ◽

Carboxyl Groups ◽

Metallic Oxides ◽

Vulcanized Rubber ◽

Synthetic Rubber ◽

Aging Properties

Abstract Scrap vulcanized rubber has been used principally for the manufacture of reclaimed rubber, which exhibits properties inherent in the original polymers of the scrap. Little has been found in the literature on the utilization of scrap vulcanized rubber as a low-cost starting material for controlled polymer synthesis. In the present investigation scraps containing natural and Type S synthetic rubbers have been modified to produce chemically different polymers possessing properties not usually associated with the initial elastomers. The authors believe that reactions with vulcanized rubber are not usually the same as reactions with the raw polymers and in this work the physical means of accomplishing the reaction are different. In 1938 Bacon and Farmer reported that when masticated raw natural rubber and maleic anhydride were dissolved in a solvent and the solution was heated in the presence of benzoyl peroxide, the ingredients reacted, yielding a variety of tough, fibrous, or resinous products. When vulcanized natural and Type S synthetic rubber scraps were reclaimed in a Reclaimator (a specially designed extruder type plasticator, made by the U. S. Rubber Reclaiming Co., Inc.) in the presence of a critical concentration of certain activated unsaturated compounds, a reaction occurred between the unsaturated compound and the scrap vulcanized rubber. With maleic anhydride, the resulting product was a carboxylated and replasticized rubber. This elastomer exhibited vulcanizing versatility via the carboxyl groups—i.e., curing with bivalent metallic oxides, diamines, glycols, epoxy resins, and diisocyanates. The polarity imparted by the carboxyl groups and the degree of crosslinking of the polymer appear responsible for its oil resistance, a property not normally present in a tire reclaim. The blocking of the double bonds, either by reaction at the double bond or by steric hindrance, added to the good aging properties anticipated with nonsulfur vulcanizates.

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Epoxy Resin Embedment

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010024x ◽

1968 ◽

Vol 26 ◽

pp. 100-101

Author(s):

J. G. Adams ◽

M. M. Campbell ◽

H. Thomas ◽

J. J. Ghldonl

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Epoxy Resin ◽

Light Microscope ◽

Epoxy Resins ◽

Image Contrast ◽

Tissue Preservation ◽

Resin System ◽

Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

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Technical notes on routine TEM procedures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012758x ◽

1987 ◽

Vol 45 ◽

pp. 630-631

Author(s):

K. Chien ◽

R.L. Van de Velde ◽

R.C. Heusser

Keyword(s):

Epoxy Resins ◽

Pathology Laboratory ◽

Silicone Fluid ◽

Image Position

Sectioning quality of epoxy resins can be improved by the addition of a 1% silicone 200 fluid (Dow Corning), however this produces a softer block. To compensate, a harder plastic has been used for embedding various tissues encountered in our pathology laboratory. Exact amounts of the plastic mixture can be directly made up for embedding as shown: The chart reveals a Poly/Bed 812 (WPE 145) to anhydride ratio of 1:0.7 and a NMA to DDSA ratio of 7:3. 1% silicone fluid is added to above mixtures.Due to impurities within the DDSA and NMA, the polymerized epoxy blocks vary in darkness and appear to affect sectioning quality. After discussing this problem with Polysciences Inc., they have agreed to purify their anhydrides in an effort to standardize the consistency of the plastic.

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Stain contamination and embedding in electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141986 ◽

1986 ◽

Vol 44 ◽

pp. 50-53

Author(s):

Hilton H. Mollenhauer

Keyword(s):

Electron Microscopy ◽

Information Retrieval ◽

Epoxy Resins ◽

Image Contrast ◽

Sample Preservation ◽

Factors Associated ◽

Amount Of Information ◽

Electron Microscopical ◽

Contrast Information

Many factors (e.g., resolution of microscope, type of tissue, and preparation of sample) affect electron microscopical images and alter the amount of information that can be retrieved from a specimen. Of interest in this report are those factors associated with the evaluation of epoxy embedded tissues. In this context, informational retrieval is dependant, in part, on the ability to “see” sample detail (e.g., contrast) and, in part, on tue quality of sample preservation. Two aspects of this problem will be discussed: 1) epoxy resins and their effect on image contrast, information retrieval, and sample preservation; and 2) the interaction between some stains commonly used for enhancing contrast and information retrieval.

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