Plasticizers in Rubbers and Plastics

1947 ◽  
Vol 20 (1) ◽  
pp. 184-206 ◽  
Author(s):  
H. Jones
Keyword(s):  
Polyvinyl Chloride ◽  
Polyvinyl Acetate ◽  
Polymer System ◽  
Amorphous Polymers ◽  
Chemical Processing ◽  
Cellulose Derivatives ◽  
New Materials ◽  
Chemical Action ◽  
The Subject ◽  
High Polymers

Abstract Up to the advent of synthetic high polymers, plasticizer technology was little understood, Plasticizers had been used mainly with cellulose derivatives, which are not at all good materials for the study of plasticizer action. The chemical processing they undergo, e.g., nitration, acetylation, etc., leads to variations on account of irregular chemical action. In addition, these materials are partly crystalline and partly amorphous. The growing numbers of new materials brought a host of problems in their train, and plasticizing was not the least of them, but a study of their behavior with plasticizers has advanced the knowledge of the plasticizer-polymer system. The principal advances have come from a study of regular and amorphous polymers, such as polyvinyl chloride, polyvinyl acetate, polystyrene, butadiene rubbers, and so on. From knowledge of these materials, one can revert to the consideration of irregular polymers such as cellulose derivatives and those produced from high polymers by additional chemical reaction, with a better likelihood of understanding their behavior with plasticizers. Thus the recent extensive use of plasticizers has led to an improved understanding of their action, and it appeared that a paper dealing with the subject might be acceptable.

The Mechanochemical Modification of High Polymers

1960 ◽  
Vol 33 (4) ◽  
pp. 923-928 ◽  
Author(s):  
R. J. Ceresa
Keyword(s):  
Free Radicals ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Natural Rubber ◽  
Polyvinyl Chloride ◽  
Polyvinyl Acetate ◽  
Mechanical Working ◽  
Linear Character ◽  
Internal Mixing ◽  
High Polymers

Abstract Degradation of natural rubber during mastication has been shown to proceed via two alternative mechanisms, oxidative scission at high temperatures and mechanical scission at lower temperatures. The low temperature process, cold mastication, has received the greater attention. The energy supplied to the extended rubber chains during mechanical deformation is sufficient to cause homolytic scission into polymeric free radicals. The degradation of high polymers by a rupture process via mechanical scission has been shown to occur during the cold mastication of synthetic elastomers and during the mechanical working of high molecular weight vinyl and acrylic polymers in the visco-elastic state. The application of shearing forces to certain polymers in the brittle glass state has provided evidence for both homolytic scission into polymeric free radicals and heterolytic scission into polymeric ions. Polymeric radicals, produced by mechanical chain scission, have been used as initiators of vinyl polymerization to give block copolymers of an essentially linear character. Thus the block copolymerizations of methyl methacrylate, styrene, vinyl acetate, acrylonitrile, and ethyl acrylate have been initiated by mechanically shearing natural rubber, polymethyl methacrylate, polystyrene, polyvinyl acetate, polyethylene, polyvinyl chloride and polyvinyl formal during the process of extrusion of the polymer plasticized to a viscoelastic state with the monomer. Many other polymer-monomer systems have yielded block copolymers by cold mastication. Cold mastication of elastomer blends, such as natural rubber and neoprene, also leads to block copolymer formation by both combinative and hydrogen abstractive processes between the different species of elastomer radicals present. If two polymers are completely compatible so that one continuous phase is present in the blend, and if the polymeric constituents have a common viscoelastic temperature range, then mechanical working during extrusion or internal mixing can lead to block copolymer formation. If the tendency of the polymeric radicals formed by mechanical rupture is to recombine rather than to disproportionate, then the chances of block copolymer formation are increased. The presence of sites for hydrogen or halogen abstraction upon one of the polymer constituents is also an aid to grafted block copolymer formation. Thus polyvinyl chloride-neoprene blends give grafted block copolymers on extrusion or internal mixing and polyethylene-polyvinyl acetate blends block copolymerize when masticated in the absence of oxygen. Block copolymerization is largely controlled by the viscoelastic properties of the systems chosen.

“Channeling” the powers of God’s Word

2010 ◽  
Vol 4 (2) ◽  
pp. 135-156 ◽  
Author(s):  
Dorothea E. Schulz
Keyword(s):  
The Other ◽  
Border Zone ◽  
Focus Attention ◽  
Spiritual Power ◽  
New Materials ◽  
God's Word ◽  
Audio Recordings ◽  
Heated Debate ◽  
The Subject ◽  
The One

Starting with the controversial esoteric employment of audio recordings by followers of the charismatic Muslim preacher Sharif Haidara in Mali, the article explores the dynamics emerging at the interface of different technologies and techniques employed by those engaging the realm of the Divine. I focus attention on the “border zone” between, on the one hand, techniques for appropriating scriptures based on long-standing religious conventions, and, on the other, audio recording technologies, whose adoption not yet established authoritative and standardized forms of practice, thereby generating insecurities and becoming the subject of heated debate. I argue that “recyclage” aptly describes the dynamics of this “border zone” because it captures the ways conventional techniques of accessing the Divine are reassessed and reemployed, by integrating new materials and rituals. Historically, appropriations of the Qur’an for esoteric purposes have been widespread in Muslim West Africa. These esoteric appropriations are at the basis of the considerable continuities, overlaps and crossovers, between scripture-related esoteric practices on one side, and the treatment by Sharif Haidara’s followers of audio taped sermons as vessels of his spiritual power, on the other.

scholarly journals XIV. On the absorption of gases by solids

1881 ◽  
Vol 32 (212-215) ◽  
pp. 407-408
Keyword(s):  
Royal Society ◽  
Hydraulic Press ◽  
Careful Examination ◽  
Solid Matter ◽  
Chemical Action ◽  
High Pressure And Temperature ◽  
Solid Iron ◽  
Series Of Experiments ◽  
The Subject ◽  
Very High

During the progress of the investigations which I have from time to time had the honour of bringing under the notice of the Royal Society, I have again and again noticed the apparent disappearance of gases inclosed in vessels of various materials when the disappearance could not be accounted for upon the assumption of ordinary leakage. After a careful examination of the subject I found that the solids absorbed or dissolved the gases, giving rise to a striking example of the fixation of a gas in a solid without chemical action. In carrying out that most troublesome investigation, the crystalline separation of carbon from its compounds, the tubes used for experiment have been in nine cases out of ten found to be empty on opening them, and in most cases a careful testing by hydraulic press showed no leakage. The gases seemed to go through the solid iron, although it was 2 inches thick. A series of experiments with various linings were tried. The tube was electro-plated with copper, silver, and gold, but with no greater success. Siliceous linings were tried fusible enamels and glass—but still the' tubes refused to hold the contents. Out of thirty-four experiments made since my last results were published, only four contained any liquid or condensed gaseous matter after the furnacing. I became convinced that the solid matter at the very high pressure and temperature used must be pervious to gases.

Biomaterial development for cardiopulmonary bypass

Perfusion ◽  
2001 ◽  
Vol 16 (5) ◽  
pp. 381-390 ◽  
Author(s):  
T Gourlay
Keyword(s):  
Cardiopulmonary Bypass ◽  
Inflammatory Response ◽  
Polyvinyl Chloride ◽  
Surface Coating ◽  
Host Defence ◽  
New Materials ◽  
Pharmacological Interventions ◽  
Defence Mechanisms ◽  
Life Threatening

Cardiopulmonary bypass (CPB) is dependent on materials foreign to the patient for its successful application. When blood comes into contact with these so-called biomaterials, an inappropriate inflammatory response, which can be life-threatening in some patients, may develop. The reason for this inappropriate activation of host defence mechanisms is not entirely clear, however a number of strategies have evolved over the years to minimize this unwanted sequelae of CPB. These strategies include surface coating of the materials of the circuit, using new materials thought to improve biocompatibility, and using a number of pharmacological interventions designed to suppress the inflammatory response. Recently, there has been some evidence which indicates that the plasticizer employed in the polyvinyl chloride (PVC) tubing of the CPB circuit may play a part in the development of the inflammatory response. The work described in this paper tends to support this thesis. These studies showed that by washing the plasticizer from the surface of the PVC tubing, the biocompatibility, as reflected in the upregulation of CD11b on the surface of neutrophils, was enhanced. Furthermore, the use of non-plasticized substitutes for PVC had a similar effect. The benefit from removing the plasticizer was similar to that gained from surface coating with heparin, one of the conventional approaches to reducing the inflammatory response to CPB.

scholarly journals The Kodak research laboratories

1948 ◽  
Vol 135 (879) ◽  
pp. 133-147
Keyword(s):  
New York ◽  
Research Laboratory ◽  
New Materials ◽  
General Electric Company ◽  
Electric Company ◽  
Light Filters ◽  
University College London ◽  
The Subject ◽  
Work Done ◽  
Dark Room

In 1880 George Eastman commenced the manufacture and sale of gelatin photographic dry plates in Rochester, New York. From that undertaking, the Eastman Kodak Company, incorporated as an American company in 1902, has developed. In 1912 Mr Eastman decided to organize a laboratory, independent of the factory laboratories, which should carry out work on both the science and practice of photography. He was influenced by his observation of the success of industrial research under Dr Whitney’s direction at the research laboratory of the General Electric Company in Schenectady, New York, U. S. A. and of the laboratories of the great German dye works. He had been particularly impressed by the work done by the Bayer Company at Elberfeld. In 1906 I had completed my thesis for the doctorate of science at University College, London, the subject being the theory of the photographic process, and had joined the old-established but very small firm of Wratten and Wainwright, Ltd., of Croydon as joint managing director. At Croydon both the conduct of research on photography and its application to the manufacture of photographic materials were continued actively, so that by 1912 many new materials had been introduced, especially panchromatic plates and the light filters and dark-room safe-lights required for their use; and the little firm was flourishing.

scholarly journals I. The emission of electrons under the influence of chemical action

1922 ◽  
Vol 222 (594-604) ◽  
pp. 1-43 ◽  
Keyword(s):  
Electromotive Force ◽  
Quantitative Information ◽  
Interesting Phenomenon ◽  
Chemical Action ◽  
Spherical Source ◽  
Spherical Electrode ◽  
The Subject ◽  
Set Up ◽  
The Individual ◽  
Sodium And Potassium

1.—Several investigators have claimed that electrons are emitted from metals under the influence of chemical action, but the only claim which seems well substantiated is that of Haber and Just, who found that when drops of cæsium or of the liquid alloy of sodium and potassium are attacked, at a low pressure, by a number of chemically active gases, the drops lose a negative but not a positive electric charge. The electric currents set up with the drops negatively charged are stopped by the application in a suitable manner of relatively small magnetic fields. This shows that the currents are carried by electrons emitted from the drops. The object of the present investigation has been to obtain quantitative information about this interesting phenomenon, and, more especially, to ascertain the magnitude of the kinetic energy of the emitted electrons and the mode of its distribution among them. The importance of the subject lies in the fact that it is the only way, so far as I am aware, in which any information at all can be made available as to the distribution of energy among the individual products—molecular, atomic, ionic or electronic—of a chemical reaction. The majority of the experiments have been directed towards obtain­ing the curves showing the relation between the chemical electron current and the applied electromotive force for the case of a small spherical source concentric with a large spherical electrode.

scholarly journals XV.—Additional Information respecting the Life and Services of Sir Walter Raleigh, in a Letter from J. Payne Collier, V.P. to William Durrant Cooper, Esq. F.S.A.

Archaeologia ◽  
1852 ◽  
Vol 34 (2) ◽  
pp. 149-159
Author(s):  
J. Payne Collier
Keyword(s):  
New Materials ◽  
Recent Letter ◽  
Additional Information ◽  
The Subject ◽  
Sir Walter Raleigh

In my recent letter to Mr. Ouvry of notes, memoranda, and documents, containing new materials for a Life of Sir Walter Raleigh, I brought the incidents with which he was connected down to the year 1584, when, as I established, he had received the honour of knighthood. I now continue the subject, and request you to be the medium of communicating what follows to our Society. The particulars, as in the former instance, are many of them minute; but, I apprehend, they are all of them more or less important, in reference to the character and conduct of a man who was highly distinguished in so many capacities, as a politician, a courtier, a soldier, a navigator, a poet, a patron, a philosopher, and a historian.

Some Words and Sentences Illustrating the Argot of the Doms

1924 ◽  
Vol 56 (2) ◽  
pp. 239-244
Author(s):  
C. Phillips Cape ◽  
Sten Konow
Keyword(s):  
Present Writer ◽  
New Materials ◽  
The Subject ◽  
The Village ◽  
The City ◽  
The Town ◽  
United Provinces

The secret language of the Ḍoms, as of other Indian “Gipsy” tribes, is very unsatisfactorily known. I have made some remarks on it in vol. xi of Sir George Grierson's Linguistic Survey, where I have also given references to such other papers about the subject as I have come across. But very much remains to be done, and we must be thankful for the new materials which are now made available. The compiler of the list says about them:—“The following is a collection of words and sentences in use by the Magahiyā Ḍoms, who have made Benares their centre or fixed abode. The language is known to wandering Ḍoms in the Panjāb, and also to those who live in the United Provinces. It was apparently unknown to village Ḍoms in Bengal, though the town and city dwellers in some parts of the Province were familiar with it. Most of the words and sentences were obtained from gipsy Ḍoms who visited Benares in 1914, and then settled in the city, where they came under the influence of the Wesleyan Methodist Mission, of which the present writer was superintendent. The sedentary Ḍoms of Benares city and the village Ḍoms of the district are acquainted with this argot.

Materials of Aircraft Construction

1938 ◽  
Vol 42 (335) ◽  
pp. 922-1032 ◽  
Author(s):  
H. J. Gough
Keyword(s):  
Structural Material ◽  
New Materials ◽  
Entire Structure ◽  
Wide Range ◽  
The Subject ◽  
Casual Observer ◽  
Wilbur Wright ◽  
Near Future ◽  
Personal Research ◽  
Limited Scope

The Wilbur Wright Lectures not only commemorate that pioneer flight on which the art of practical aviation was founded but also offer homage to the brilliant research and invention which made that flight possible. It is, therefore, natural and fitting that such a large proportion of the preceding 25 lectures have dealt specifically with the application of research to matters aeronautical. The materials of aeronautical construction can also justly be classed as the outcome of much research into many fields of pure and applied science, with practical results that have made some contribution towards the advancement of aviation and, hence, fittingly form the subject of a Wilbur Wright Lecture. Accordingly, when the Council of the Royal Aeronautical Society honoured me with the invitation to deliver the 1938 lecture on this subject, I naturally read up the preceding lectures and was somewhat surprised to find that materials, as such, had not previously been dealt with in this connection. The task of making the first survey of a field of such alarming scope, in a necessarily limited space and time, involved some anxious reflection regarding a suitable method of treatment; it appeared that a detailed discussion of personal research, or even of a selected group of materials, must have such a limited scope as to be incompatible with what is implied in the allotted title. To the casual observer, the really wide range of the more familiar materials of construction that have been available for some years, allied to the normal steady improvements that have been effected and those that may be expected, may appear to offer all that is required for the aeronautical requirements of the next decade or so, so that reviews of the materials of, say, 1924, 1931, 1938 and 1945 would mainly represent a story of development rather than change ; actually, this is not the position. A relatively few years has seen the relinquishment, temporary or permanent, of the position held by steel as a structural material; the use of light alloys has become very general, an improved form of wood is definitely in the field while it may be that the entire structure of moulded plastics will become a practical proposition in the fairly near future. Then, the accomplishment of the aims of the engine builder with regard to units of much greater powers are retarded to a certain extent by the fact that a number of materials appear to have reached the visible peak of their development; new materials are urgently required. Again, who would care to prophesy that the airscrew of the future 2,000-4,000 h.p. engine will even be made of any kind of metal, although the present aluminium alloy propellers give such good performance.

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