Phenolics types

Duolite A-7 2.2 1.12 Phenolic type resin. High porosity and hydrophilic matrix. pH range is 0 to 6. 

Catalyst residues, particularly vanadium and aluminum, have to be removed as soluble salts in a water-washing and decanting operation. Vanadium residues in the finished product are kept to a few ppm. If oil-extended EPDM is the product, a metered flow of oil is added at this point. In addition, antioxidant, typically of the hindered phenol type, is added at this point. 

In unreacted phenol-type materials they are present as impurities. 

Since the last edition several new materials have been aimounced. Many of these are based on metallocene catalyst technology. Besides the more obvious materials such as metallocene-catalysed polyethylene and polypropylene these also include syndiotactic polystyrenes, ethylene-styrene copolymers and cycloolefin polymers. Developments also continue with condensation polymers with several new polyester-type materials of interest for bottle-blowing and/or degradable plastics. New phenolic-type resins have also been announced. As with previous editions I have tried to explain the properties of these new materials in terms of their structure and morphology involving the principles laid down in the earlier chapters. 

Process 4, conversion of peroxy radicals to hydroperoxides can be interrupted by traditional primary antioxidants (see Fig. 16). The fastest reacting primary antioxidants are the aromatic amines (e.g. Naugard 445). However, these materials yellow upon exposure to UV light which restricts their applieations. More common in adhesives are the hindered phenol types of which numerous types are available, with Irganox 1010 the most common choice for adhesives. 

As tannins contain many phenolic -type subunits (Fig. 3), one may be tempted to think that they will exhibit a similar reactive potential to that of phenol, and that therefore procedures used in standard PF production can be transferred to those containing tannin. This, however, is not the case. The real situation is that tannin is far more reactive than unsubstituted phenol due to the resorcinol and catchecol rings present in the tannin. This increase in hydroxyl substitution on the two aromatic rings affords an increase in reactivity to formaldehyde by 10 to 50... 

Since the individual members of this group of media differ considerably in properties, so also do the finishes that can be made from them. As a class, however, they are generally inferior to the better alkyds for durability under normal conditions. A particular exception is the tung-oil 100% phenolic type of medium, which produces finishes with very good resistance to water and mildly acidic or alkaline conditions pale colours, however, discolour by yellowing on exposure. 

These are thermoset polymers made from phenol or, less commonly, phenolic-type compounds such as the cresols, xylenols, and resorcinol, together with formaldehyde. They had been known for some time - G.T (later Sir Gilbert) Morgan discovered them in the early 1890s when attempting (unsuccessfully) to make artificial dyestuffs by reaction of phenol with formaldehyde. But this knowledge had not been exploited before 1907, the year in which Leo... 

Standardisation of EPDM characterisation tests (molecular composition, stabiliser and oil content) for QC and specification purposes was reported [64,65]. Infrared spectroscopy (rather than HPLC or photometry) is recommended for the determination of the stabiliser content (hindered phenol type) of EP(D)M [65]. Determination of the oil content of oil-extended EPDM is best carried out by Soxhlet extraction using MEK as a solvent [66], A round robin test was reported that evaluated the various techniques currently used in the investigation of unknown rubber compounds (passenger tyre tread stock formulations) [67]. 

Figure 6 Representative (A) phenol-type and (B) phenylboronic acid-type enhancers for luminol/hydrogen peroxide/peroxidase system. KIH-201, 2-(4 -hydroxy-3 -methoxy-benzylidene)-4-cyclopentene-1,3-dione HDI, 2-(4-hydroxyphenyl)-4,5-diphenylimida-zole HPI, 2-(4-hydroxyphenyl)-4,5-di(2-pyridyl)imidazole DPPA, 4-[4,5-di(2-pyridyl)-lH-imidazol-2-yl]phenylboronic acid).

Alkenyloxystyrene monomers such as 4-allyloxystyrene are useful components of photocured cationically polymerizable compositions. Used alone or in combination with divinyl ethers they provide low viscosity formulations, which are excellent solvents for commercial onium salt photoinitiators. Photocuring rates are comparable to vinyl ether monomers and the initially photocured alkenyloxystyrene polymers may be further heat processed to yield crosslinked phenolic type resins having outstanding thermal resistance properties. The new materials have good adhesive properties and are potentially useful where a combination of ease of processability and high performance is required. 

Classifying particles, in filtration, 11 326 Class I hybrids, 13 536, 543, 544 Class II hybrids, 13 536, 543 Clastogenesis, 25 206 Clathrate hydrates, 14 170—171 Clathrate receptor chemistry, 16 797 Clathrates, 12 374 14 159, 170-182 formation of, 10 633-635 26 869 Hofmann- and Werner-type, 14 171-172 phenol-type, 14 180 tri-o-thymotide, 14 179 Claus catalysts... 

Antioxidants act so as to interrupt this chain reaction. Primary antioxidants, such as hindered phenol type antioxidants, function by reacting with free radical sites on the polymer chain. The free radical source is reduced because the reactive chain radical is eliminated and the antioxidant radical produced is stabilised by internal resonance. Secondary antioxidants decompose the hydroperoxide into harmless non-radical products. Where acidic decomposition products can themselves promote degradation, acid scavengers function by deactivating them. 

Fragmentation of the nitrite then yields a phenolic-type ion that can decompose further by elimination of CO. Thus, the characteristic series of [M-ld]" (generally weak signal), [M-30] and [M-46] ions is obtained (Fig. 6.49a,b). 

H. S. Olcott (University of California, Berkeley, Calif.) We have studied the effects of aliphatic amines on the autoxidation of a fish oil and squalene in air at moderate temperatures. There was little protection unless phenolic-type inhibitors were also added, in which case secondary amines were more effective than primary or secondary amines. However, at 70 °C. trioctylamine alone protected the fish oil, whereas at lower temperatures it did not (2). Further study revealed that peroxides react with trioctylamine to yield some dioctylhydroxylamine which has antioxidant properties (1). These and other observations (3) indicate that... 

A typical hindered phenol-type fuel antioxidant... 

When acid chelators are combined with one of the phenolic-type antioxidants, they can act synergistically. This type of synergism has been referred to as acid synergism (S). In this case, the primary role of a chelator is to bind metals, or metalloproteins that promote oxidation and thus, allow the antioxidant to perform its function and capture free radicals. In this manner, acid synergism is different than the BHA/BHT system. 

When the antioxidants were used in the cooked/stored samples, data indicated that they were very effective in inhibiting lipid oxidation and MFD. The chemical and off-flavor indicators were reduced and the on-flavor notes were increased. Thus, phenolic-type primary antioxidants that function as free radical scavengers are very effective tools for preventing lipid oxidation and MFD in ground beef. It should also be noted that the intensity of the desirable flavor notes remained at very high levels, which meant that the patties retained their beefy tastes. Therefore, for an antioxidant to be highly effective, it should not only prevent lipid oxidation, but it should also retain the desirable flavor properties of the food commodity. 

Vinylidene Chloride Monoperoxide. When vinyli-dene chloride is stored without a polymerization inhibitor (such as tertiary butyl catechol or other phenol type inhibitors) at a temp of between -40 and +25° in the presence of air or oxygen, the 02 dissolves to form a peroxide compd of undetermined nature which is an extremely violent expl This peroxide seems to act as a polymerization catalyst because its formation is often accompanied by the pptn of a flocculent vinylidene chloride polymer. Since the peroxide is absorbed on the pptd polymer, any separation... 

The important methods involve ring closure of o-substituted anilines and phenols (type 108) and cyclization of o-unsubstituted aniline, etc., derivatives (type 109). Additionally, cycloadditions and transformations from other heterocycles are considered. Table 2 gives an overview of the important methods for preparation of derivatives of these types. 

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