The State of Aggregation of Rubber and of Substances with Rubberlike Extensibility.

Meyer, Kurt H.

doi:10.1021/cr60081a001

Cited by 5 publications

(10 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The longrange elastic characteristics are not dependent on the presence of crosslinks, but probably result from the ability of flexible chain molecules to contract from the less probable stretched state to a more random form. Meyer [26] and Mark [27] have reviewed the evidence for this view of the origin of long-range elasticity. The function of cross-links is to strengthen the materials and suppress plastic flow, The introduction of a higher proportion of cross-links would decrease the flexibility and reduce the range of elasticity, as illustrated by the properties of highly vulcanized rubber (ebonite).…”

Section: Discussionmentioning

confidence: 99%

Elasticity of wool as related to its chemical structure

Harris¹,

Mizell²,

Fourt³

1942

J. RES. NATL. BUR. STAN.

View full text Add to dashboard Cite

Wool protein, like other fibrous proteins. is composed of long, fle xible molecular chains. This flexibility appears to be the basis of the "long-range" elasticity of wool fibers. The wool fiber is distinguished from othu textile fibers by the presence of covalent disulfide cross-links between these main chains. Rupture of these links by chemical means decreases the strength of the fiber without necessarily affecting the elastic recovery. Rebuilding the covalent linkages largely restores the original properties of the fiber.Wool appears to be analogous to rubber in several r espects. Thus the stressstrain, solubility, and swelling characteristics are greatly influenced by the extent of cross-linking in the two materials.

show abstract

Section: Discussionmentioning

confidence: 99%

Elasticity of wool as related to its chemical structure

Harris¹,

Mizell²,

Fourt³

1942

J. RES. NATL. BUR. STAN.

View full text Add to dashboard Cite

show abstract

“…As predicted by statistical mechanics, a system tends to assume the most thermodynamically probable state when left to itself. In substances such as rubber, which possess long-chain, flexible molecules, the completely extended state is only one among the many The Structure of Protoplasm possible configurations of the molecule and, hence, will occur very infrequently under these conditions (18,21). Stretching the system can be made to produce extension and alignment of the flexible chains with a lessening of the probability of the system and a concomitant decrease in the entropy.…”

Section: Double Refraction Of Protoplasmmentioning

confidence: 99%

“…Although these fibers show only slight birefringence when unstained, they are clearly anisotropic after treatment with a cellulose dye such as Congo red. This increase in birefringence upon staining is due, apparently, to the double refraction of the dye molecules which are preferentially adsorbed by the small amount of cellulose which is present (12,21) . Although a number of investigators have suggested that the skeletal material in the primary wall is not cellulose but a closely related substance, X-ray investigations (11,28), staining reactions (2, 17), and behavior in cuprammonium hydroxide solutions (2, 17) indicate that it is probably cellulosic in nature.…”

Section: Introduction William Seifrizmentioning

confidence: 99%

“…It was noticed by Freundlich and Seifriz (12), for instance, that only those soap solutions which contained rod-shaped aggregates were elastic. Gelatin (12,14), elastoidin (37) , elastin (21,37) , and collagen (14,37) , to name a few proteins, can all be brought into an elastic state. These are members of the fibrous or extended group.…”

mentioning

confidence: 99%

“…As mentioned above, when rubber-like substances are stretched, an extension of the molecular chains may take place without a change in internal energy. If, however, the chains become oriented enough to produce crystalHzation, the internal energy decreases, due to the liberation of heat of crystallization (21,37). In a normal elastic solid, such as a steel spring, stretching results in an increase in the internal energy by pulling the atoms out of their troughs of minimal potential energy.…”

mentioning

confidence: 99%

See 2 more Smart Citations

A symposium on the structure of protoplasm / edited by William Seifriz.

Seifriz¹

1942

View full text Add to dashboard Cite

The Structure of Protoplasm matter is very probably due to a specific arrangement of parts, that is to say, to structure. Often I am asked by physicists and chemists if much can be hoped for in the way of an understanding of protoplasmic structure. Direct observation, even with the highest powers of the microscope, is too superficial to reveal anything fundamental. Chemical analysis is not productive of significant results because once protoplasm is subjected to severe treatment it is no longer living matter. The very structural features which distinguish it from the nonliving are then destroyed. The biologist interprets the basic structure of protoplasm somewhat in the same way that a chemist interprets the structure of a compound, namely, by its behavior. The chemist sees nothing of the links, rings, side chains, amino and carboxyl groups which he attaches here and there, yet he builds up a structure with considerable confidence, which is the justification of stereochemistry. Just so does the biologist work; he interprets the structure of living matter in the light of its known physical properties. But this was not the method of the older biologists, and herein lay their error. They told only of what they saw. Protoplasm viewed through the microscope appears to be a suspension of fine granules. On this fact was based the granular hypothesis of protoplasmic structure. Its weakness lay in the diversity of the granules and the undue significance given them. Some are admittedly important, as are the plastids and the mitochondria; others, such as fat droplets, are but reserve food. These last are really not granules at all but liquid droplets which make of cytoplasm a fine emulsion. The importance attributed to the "granules"-they were regarded by some as living units, morphologically and physiologically independent of the cell-and the necessary coarseness of any optically visible structure, led to the discarding of the granular hypothesis. The belief that the basic structural unit of protoplasm is a spherical body has long persisted and has given rise to numerous hypotheses expressed in terms of granules, globules, alveoli, and micellae. Such suggestions are in part supported by fact. Thus, protoplasm is unquestionably an emulsion, and when the emulsion globules are under pressure and symmetrically arranged they assume the shape of dodecaor tetrakaidecahedra which are hexagonal in cross section. These latter are alveoli.

show abstract

Kinetics of cellular processes

Seifriz¹

1956

Allgemeine Physiologie Der Pflanzenzelle / General Physiology of the Plant Cell

View full text Add to dashboard Cite

The State of Aggregation of Rubber and of Substances with Rubberlike Extensibility.

Cited by 5 publications

References 8 publications

Elasticity of wool as related to its chemical structure

Elasticity of wool as related to its chemical structure

A symposium on the structure of protoplasm / edited by William Seifriz.

Kinetics of cellular processes

Contact Info

Product

Resources

About