Polymerization

“ Under the conditions, too, existing beneath the surface of the earth, such polymerization as is necessary to account for the presence of the different classes of hydrocarbons found in petroleum is scarcely credible. ”

“ The concentration of the solution is increased, the osmotic pressure is raised, and we have a hypertonic centre of diffusion. Every centre of catabolism is therefore a positive pole of diffusion. Similar considerations as to the formation and breaking up of the molecules in anabolism and catabolism apply to polymerization. ”

“ Vinyloid A and Gelva represent the simplest series of vinyl acetate resins and are made by polymerizing the monomer. The softening point and viscosity of the polyvinyl acetate resins increase with higher polymerization. Such resins are colorless, tasteless, odorless, thermoplastic products. They are soluble in coal-tar solvents and are compatible with certain alkyd resins, tar-acid resins, and natural resins. Films of polyvinyl acetate resin are not discolored by exposure, and after irradiation they become opaque to ultraviolet light, are hard and tough, and have good adherence and endurance. ”

“ For example, vinylite is produced by polymerization of a mixture of vinyl acetate and vinyl chloride.
C-stage resins.—Thermosetting resins in the final stage in which they are infusible and insoluble. The state of the resin in the final molded article.
Curing.—The change of a binder from the soluble-fusible condition to the substantially insoluble-infusible form by chemical action. The heat-setting of a resinoid. Action is analogous to vulcanization of rubber. ”

“ Dealing with organic compounds, it is metamerism that deserves chief attention, as it has largely developed our notions as to molecular structure. Polymerism required no particular explanation, since this was given by the difference in molecular magnitude. One general remark, however, may be made here. There are polymers which have hardly any inter-relations other than identity in composition; on the other hand, there are others which are related by the possibility of mutual transformation ”

“ I. The inertness of this polymer to chemical reagents, its insolubility, and its resistance to heat and to fire make its use desirable in many places. By the use of sufficiently high pressure and temperature it can be molded into articles which are relatively clear and colorless. Such articles are laboratory apparatus for handling corrosive reagents, disks for goggles used in corrosive atmospheres, such as those which pervade certain chemical plants, and the material may be extruded into fibers which can be used in the manufacture of heat-resistant clothing and the like. ”

“ The easy transitions of the ortho-, meta-, and pyrophosphoric acids, by means of the hydrogen of ammonia, into the lower acids, and conversely, tend to complicate the study of this very large class of compounds, and it is rarely that the nature of a product thus obtained can be judged from its composition; and this all the more that instances of isomerism and polymerism, of mixture between water of crystallisation and of constitution, &c., are here possible. Many data are yet needed to enable us to form a true judgment as to the composition and structure of such compounds. ”

“ If the solution is kept below 45° C., by artificial cooling, the light colour is maintained, but a gelatinous precipitate is soon formed, the viscosity of which increases on stirring, and finally is converted into an insoluble, tough, gummy mass. If, on the other hand, the mass is heated at the beginning of the reaction, or if the amount of formaldehyde is increased and the mass cooled during reaction, effervescence occurs, and a cheesy, dirty-coloured mass results, which, on cooling, rapidly becomes solid and yields a very firm, elastic, rubbery mass, which is absolutely insoluble in water. ”

“ The problem was somewhat complicated by the development of polymorphism, the methyl, ethyl, and propyl compounds having each been found to be dimorphous, and not improbably trimorphous, but only two varieties of each salt were obtained in crystals adequately perfect for measurement. That the production of these different forms was due to polymorphism and not to chemical isomerism (different arrangement of the chemical atoms in the molecule) was shown by the fact that one variety could be obtained from the other by simply altering the conditions of crystallisation from the same solvent. ”

“ In my opinion the progress of chemistry, especially with regard to solutions, should make rapid strides when the cause of the isomerism of solutions, for instance, of ortho- and pyrophosphoric acids, has become as clear to us as the cause of many well-studied instances of the isomerism, polymerism, and metamerism of organic compounds. ”

“ If you have ever played ring-around-a-rosy you will get the idea. In Chapter IV I explained that the anilin dyes are built up upon the benzene ring of six carbon atoms. The rubber ring consists of eight at least and probably more. Any substance containing that peculiar carbon chain with two double links C=C-C=C can double up—polymerize, the chemist calls it—into a rubber-like substance. So we may have many kinds of rubber, some of which may prove to be more useful than that which happens to be found in nature. ”

“ The group relations are borne out by the isomorphism of many related salts. The hydroxide and oxide show polymeric modifications, and the former has the usual tendency of compounds of this group to form colloidal solutions, a tendency which extends to the element itself. The metal resembles titanium in the eagerness with which it combines with other elements, especially with oxygen, nitrogen, and carbon, whilst the chloride closely resembles titanium tetrachloride in general properties, and in the ease with which it forms addition and condensation products with other substances. ”

“ Isomerism.—Certain investigations on isomerism which have become especially prominent in recent times bear on the possibility of the mutual transformation of isomers. As soon as this reversibility is introduced, general laws related to thermodynamics are applicable (see Chemical Action; Energetics) . These laws have the advantage of being applicable to the mutual transformations of isomers, whatever be the nature of the deeper origin, and so bring polymerism, metamerism and polymorphism together. ”

“ Synthetic resin.—A complex, substantially amorphous, organic semisolid or solid material (usually a mixture of substances) built up by chemical reaction of comparatively simple compounds and, depending upon the temperature at which the examination is made, approximating the natural resins in various physical properties: namely, luster, fracture, comparative brittleness, insolubility in water, fusibility or plasticity when heated or exposed to heat and pressure, and, at a certain more or less narrow temperature range before fusion, showing a degree of rubberlike extensibility ”

“ Cases of isomerism in the restricted sense of the word—that is, when with an identity of composition and of molecular weight, the properties of the substances are different—are very numerous among the hydrocarbons and their derivatives. Such cases are particularly important for the comprehension of molecular structure and they also, like the polymerides, may be predicted from the above-mentioned conceptions, expressing the principles of the structure of the carbon compounds [42] based on the law of substitution. ”

“ Its forms and combinations are extremely varied, but it always consists of the same chemical elements, carbon, hydrogen and oxygen, and in the same proportions. It is the object of the paper-maker to eliminate the glutinous, resinous, siliceous and other intercellular matters and to produce the fibre as pure and as strong as possible. Linen and cotton rags, having already undergone a process of manufacture, consist of almost pure fibres with the addition of fatty and colouring matters which can be got rid of by simple boiling under a low pressure of steam with a weak alkaline solution ”

“ REAGENTS: 1. Super absorbent polymer (the type present in air samples) , 99+% pure if water is only impurity. See step 15 to determine the amount of water present. 2. Copper acetate, 0.07 M. Dissolve 27.96 g of cupric acetate monohydrate in water to make 2 L of solution. Solution may be stored at least 6 months. Filter solution through 0.45μm cellulose ester filter immediately (<4 h) before use. 3. Water, deionized. 4. Sucrose, 99+% pure. 5. Calibration stock mixture, ca. 4% super absorbent polymer by weight. ”

“ A number of these condensation products are derivatives of diphenylamine or hydroxybenzyl alcohols. When the latter are heated, either by themselves or in presence of acids, anhydrides and polymerisation products are formed producing hard, brittle, fusible substances, insoluble in water but fairly soluble in organic solvents. The same substances are formed when phenols are condensed with formaldehyde, especially in the presence of acid contact substances and excess of phenol by sufficiently long heating at certain temperatures. ”

“ If the sulphonic acid is diluted with three times its volume of water, cooled down, a few drops of formaldehyde added and the mixture heated on the water bath to completely fix the formaldehyde, and this process repeated till no more formaldehyde is taken up, a brown water-soluble condensation product results, the aqueous solution of which precipitates gelatine completely, aniline hydrochloride only partly and which gives a deep blue colour with ferric chloride. ”

“ But simple as the substance appears, composition is really very complicated. Professor Allman tells us that so difficult and wonderful is its chemistry, that in fact really very little is known about it. The best evidence we have, I believe, makes it tolerably certain that protoplasm consists of a combination of ammonia, carbonic acid, and water, and that every molecule of it is made up of 76 atoms, of which 36 are carbon, 26 hydrogen, 4 nitrogen, and 10 oxygen. ”

“ For each sample, accurately weigh 50 to 300 mg of a working standard polymer-sucrose mixture) in a 20-mL vial on a five-place balance. Place a 37-mm PVC filter into each vial. b. Follow steps 9, 11 through 14, and 18 and 19. c. Determine each quantity of super absorbent polymer found from the calibration graph (step 16. g) . d. Calculate the recovery for each sample by dividing the quantity of super absorbent polymer found by the original quantity of polymer. NOTE: Each recovery is an estimate because the PVC filters have not been fortified with super absorbent polymer. ”

“ Monovinyl acetylene reacts with hydrochloric acid to give chloroprene, which is polymerized to synthetic rubber or Neoprene.
Divinyl acetylene is a colorless liquid which darkens on exposure to light and which has an onionlike odor. When polymerized liquids are formed, then as the reaction progresses viscous products and finally insoluble, infusible, inert resins. By arresting the reaction before the gel point is reached, an amber colored heavy liquid, soluble in aromatic hydrocarbons, is obtained. ”

“ Coating And Fusion.—Difficulties of either may generally be done away with by reducing the magnesia used in the frit to a minimum.
A soft surface is always the outcome of a mixing which can be fused at a low temperature. It is due to too much lead or an insufficiency of clay or silica powder.
A hard surface is due to the quantity of lead in the mixing being too small. Increase the quantity and introduce potash, say about 2.5 per cent.
The gray or fundamental mixing should be kept together in a condition only just sufficiently liquid to allow of being poured out. ”

“ The end of the splints are generally scorched by contact with a hot plate before they are dipped in the paraffin, after which the phosphorus composition is applied to the match. This composition is simply a mixture of phosphorus, glue, and chlorate of potash. The composition is spread upon a warm plate, and the matches dipped on the plate, so that a small quantity of the phosphorus mixture may adhere to the tip of the match. Every match passes through about seventeen people's hands before it is finished. ”

“ From the negative a positive is made upon a copper or zinc plate, suitably coated with a sensitive film. The usual practice is to coat the polished metal plate with a mixture of water, albumen, fish glue, ammonium bichromate, chromic acid and ammonia; the plate is then dried and, when cooled, exposed under the negative. The action of the light on such a film, the essentials of which are the albumen, the glue or gelatine and a chromate, has already been described. The mixture becomes more or less insoluble in water, according to the intensity of the light falling upon it. ”

“ To summarize, we have to deal with polymerism, metamerism, stereoisomerism, polymorphism; whereas phenomena denominated tautomerism, pseudomerism and desmotropism form different particular features of metamerism, as well as the phenomena of allotropy, which is merely the difference of properties which an element may show, and can be due to polymerism, as in oxygen, where by the side of the ordinary form with molecules O2 we have the more active ozone with O3. ”

“ The condensation product easily dissolves in water, the solution assuming a rich brown colour and exhibiting the following reactions: gelatine is completely precipitated, aniline hydrochloride produces opalescence, and ferric chloride a deep brown coloration. ”

“ Let the solubility, which represents the concentration of the solvent in the membrane at this stage, be called c. The membrane may then be considered to be taking up in unit time just as many molecules from the solvent as it gives up to it (dynamic equilibrium) , exactly as, when water is in equilibrium with water vapor, we consider the water to be vaporizing just as fast as vapor is condensing to form water. Now, if a solution of sugar is placed on the other side of the membrane, the solvent will pass out of the membrane into the solution just as fast as it passes back into the pure solvent. ”