Composites Condensation products

The reaction conditions, formaldehyde-to-phenol ratios, and concentration and type of catalyst govern the mechanisms and kinetics of resole syntheses. Higher formaldehyde-to-phenol ratios accelerate the reaction rates. This is to be expected since phenol-formaldehyde reactions follow second-order kinetics. Increased hydroxymethyl substitution on phenols due to higher formaldehyde compositions also leads to more condensation products.55... 

The chemical and physical properties of the polymers obtained by these alternate methods are identical, except insofar as they are affected by differences in molecular weight. In order to avoid the confusion which would result if classification of the products were to be based on the method of synthesis actually employed in each case, it has been proposed that the substance be referred to as a condensation polymer in such instances, irrespective of whether a condensation or an addition polymerization process was used in its preparation. The cyclic compound is after all a condensation product of one or more bifunctional compounds, and in this sense the linear polymer obtained from the cyclic intermediate can be regarded as the polymeric derivative of the bifunctional monomer(s). Furthermore, each of the polymers listed in Table III may be degraded to bifunctional monomers differing in composition from the structural unit, although such degradation of polyethylene oxide and the polythioether may be difficult. Apart from the demands of any particular definition, it is clearly desirable to include all of these substances among the condensation... 

Consider the binary batch distillation column, represented in Fig. 3.58, and based on that of Luyben (1973, 1990). The still contains Mb moles with liquid mole fraction composition xg. The liquid holdup on each plate n of the column is M with liquid composition x and a corresponding vapour phase composition y,. The liquid flow from plate to plate varies along the column with consequent variations in M . Overhead vapours are condensed in a total condenser and the condensate collected in a reflux drum with a liquid holdup volume Mg and liquid composition xq. From here part of the condensate is returned to the top plate of the column as reflux at the rate Lq and composition xq. Product is removed from the reflux drum at a composition xd and rate D which is controlled by a simple proportional controller acting on the reflux drum level and is proportional to Md-... 

The structures of sol-gel-derived inorganic polymers evolve continually as products of successive hydrolysis, condensation and restructuring (reverse of Equations 1-3) reactions. Therefore, to understand structural evolution in detail, we must understand the physical and chemical mechanisms which control the sequence and pattern of these reactions during gelation, drying, and consolidation. Although it is known that gel structure is affected by many factors including catalytic conditions, solvent composition and water to alkoxide ratio (13-141, we will show that many of the observed trends can be explained on the basis of the stability of the M-O-M condensation product in its synthesis environment. 

As outlined elsewhere (A), we have employed a variation of the original reaction hy Lambourne (3) in exploring condensation products leading to the drum composition as well as to a mixed oxycarboxylate-tricarboxylate formulation, [ (R Sn(0)02CR) 2R Sn CR) 3 ] 2. The latter was identified as having an unfolded drum or ladder structure (A). 

It is difficult to use the model as a predictive model, since this would imply the knowledge of the chemical composition of the indoor atmosphere, as well as the formation rates of some relevant condensable products, which is hard to achieve. Linking... 

Potassium perchlorate (KP KCIO4) is a weU-known oxidizer, used as an oxidizer component of black powder. Since KP produces potassium oxides and condensed products, the high molecular mass Mg of the combustion products is not favorable for its use as an oxidizer in rocket propellants. A mixture of 75 % KP with 25 % asphalt pitch was used as a rocket propellant named Galcit, which was the original prototype of a composite propellant in the 1940 s. Potassium chlorate (KCIO3) is also a crystalline oxidizer, and although it has a lower oxygen content compared... 

The primary resin of interest is epoxy. Carbon-fiber-epoxy composites represent about 90% of CFRP production. The attractions of epoxy resins are that they polymerize without the generation of condensation products that can cause porosity, they exhibit little volumetric shrinkage during cure which reduces internal stresses, and they are resistant to most chemical environments. Other matrix resins of interest for carbon fibers include the thermosetting phenolics, polyimides, and polybismaleimides, as well as high-temperature thermoplastics such as polyether ether ketone (PEEK), polyethersulfone (PES), and polyphenylene sulfide. 

Minachev, Eidus et al. (25) found that Ca, Ni, Co, and NdY zeolites were active in the disproportionation of propylene to ethylene and butenes. The process was accompanied by hydrogen rearrangement to form saturated hydrocarbons and condensation products. The selectivity in this reaction depends on the composition of the catalysts, their pretreatment, and the experimental conditions (26). 

Clarification by removal of casein with such agents as calcium chloride, acetic acid, cooper sulfate, or rennin has often been employed to obtain a serum more suitable for refractometric measurements. Obviously the composition, and hence the refractive index, of such sera will depend on the method of preparation. Furthermore, some of the serum proteins may be precipitated with the casein by some of the agents used, particularly if the milk has been heated. Refractive index measurements of such sera are not generally considered as satisfactory as freezing point measurements for detection of added water (David and MacDonald 1953 Munchberg and Narbutas 1937 Schuler 1938 Tell-mann 1933 Vleeschauwer and Waeyenberge 1941). Menefee and Overman (1939) reported a close relation between total solids in evaporated and condensed products and the refractive index of serum prepared therefrom by the copper sulfate method. Of course, a different proportionality constant would hold for each type of product. 

ICI Limited (Great Britain) Aqueous Explosive Composition Containing as a Sensitizer a Condensation Product of Ethylene Oxide with a Phenol or Saturated Carboxylic Acid... 

The same composition of the magnesium cluster adducts with halides and hydrocarbons confirm the above conclusion that the composition of primary condensation products is determined by the competition between... 

After the vacuum distillation and rectification tank residue consists of condensed products, e.g. oligomers of the following composition (C2H50)2RSi0—[(C2H50)RSi0]n—Si(OC2H5)2R... 

A thermohardening composition for glass fiber reinforced plastics consists of PPO, BPA/DC and a bismaleimide [45]. Still higher heat resistance is achieved, if the poly-functional maleimide, based on aniline-formaldehyde condensation products (Scheme 11), is used [46]. 

Semikolenov, G. F P(xlobaev, N. 1., and Voskresenskii, A. G., Chemical composition of the acid-corrosion inhibitor PKU [urotro-pinc based condensation product], Innibiton 324. Korroz. Met., 127, 1972. 

Composition sulfonic acid formaldehyde condensation product... 

Composition fatty acid condensation product Appearance off-white pourable paste Ionic Nature slightly cationic pH (as is) 4-5 Activity, % 20... 

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