Vinyl index

Similar increases in carbonyl index, vinyl index and crystallinity have also been reported for rape straw flom (RSF)/HDPE and nano-SiO /RSF/ HDPE composites exposed to natural weathering for 120 days by Zuo et al. [61]. 

Comprehensive Index Vinyl Ester - Laminating Resins... 

Antimony Oxide. The effect of antimony trioxide on the oxygen index of flexible poly(vinyl chloride) containing from 20 to 50 parts of plasticizer is shown in Figure 2. The flame resistance as measured by the oxygen index increases with the addition of antimony oxide until the oxygen index appears to reach a maximum at about 8 parts of Sb202. Further addition of antimony oxide does not have any increased beneficial effect. 

Fig. 2. The effect of antimony oxide on the oxygen index of poly(vinyl chloride) plasticized with dioctyl phthalate (DOP), (—...

Alumina Trihydrate. Alumina trihydrate is usually used as a secondary flame retardant in flexible PVC because of the high concentration needed to be effective. As a general rule the oxygen index of flexible poly(vinyl chloride) increases 1% for every 10% of alumina trihydrate added. The effect of alumina trihydrate on a flexible poly(vinyl chloride) formulation containing antimony oxide is shown in Figure 5. 

Ethyl Vinyl Ether. The addition of ethanol to acetylene gives ethyl vinyl ether [104-92-2] (351—355). The vapor-phase reaction is generally mn at 1.38—2.07 MPa (13.6—20.4 atm) and temperatures of 160—180°C with alkaline catalysts such as potassium hydroxide and potassium ethoxide. High molecular weight polymers of ethyl vinyl ether are used for pressure-sensitive adhesives, viscosity-index improvers, coatings and films lower molecular weight polymers are plasticizers and resin modifiers. 

Poly(vinyl acetate) is too soft and shows excessive cold flow for use in moulded plastics. This is no doubt associated with the fact that the glass transition temperature of 28°C is little above the usual ambient temperatures and in fact in many places at various times the glass temperature may be the lower. It has a density of 1.19 g/cm and a refractive index of 1.47. Commercial polymers are atactic and, since they do not crystallise, transparent (if free from emulsifier). They are successfully used in emulsion paints, as adhesives for textiles, paper and wood, as a sizing material and as a permanent starch . A number of grades are supplied by manufacturers which differ in molecular weight and in the nature of comonomers (e.g. vinyl maleate) which are commonly used (see Section 14.4.4)... 

Ethylenevinylacetate (EVA) is the most used type (approximately 80%) it can be varied in viscosity (melt index) and content of acetate in broad ranges. It is semicrystalline. The vinyl acetate groups provide improved adherability towards many materials. The low heat stability, however, limits the areas of application. 

Another publication is the Index of Reviews in Organic Chemistry , complied by Lewis, Chemical Society, London, a classified listing of review articles. The first volume, published in 1971, lists reviews from 1960 (in some cases much earlier) to 1970 in alphabetical order of topic. Thus four reviews are listed under Knoevenagel condensation , five under Inclusion compounds , and one under Vinyl ketones. There is no index. A second volume (1977) covers the literature to 1976. Annual or biannual supplements appeared from 1979 until the publication was terminated in 1985. Classified lists of review articles on organometallic chemistry are found in articles by Smith and Walton and by Bruce.A similar list for heterocyclic chemistry is found in articles by Katritzky and others.See also the discussion of the Index of Scientific Reviews, page 1638. 

Aryloxyphosphazene copolymers can also confer fireproof properties to flammable materials when blended. Dieck [591] have used the copolymers III, and IV containing small amounts of reactive unsaturated groups to prepare blends with compatible organic polymers crosslinkable by the same mechanism which crosslinks the polyphosphazene, e.g. ethylene-propylene and butadiene-acrylonitrile copolymers, poly(vinyl chloride), unsaturated urethane rubber. These blends were used to prepare foams exhibiting excellent fire retardance and producing low smoke levels or no smoke when heated in an open flame. Oxygen index values of 27-56 were obtained. 

Flexible foams with oxygen index values of 40-53 were also prepared by the same authors from blends of copolymer IV and a silicone elastomer, (a phenyl vinyl polydimethylsiloxane) [592]. 

A way to narrow the MWD and to approach the structure of dendrimers is the addition of a small fraction of a/-functional initiator, to inimers [40,71]. In this process the obtainable degree of polymerization is limited by the ratio of inimer to initiator. It can be conducted in two ways (i) inimer molecules can be added so slowly to the initiator solution that they can only react with the initiator molecules or with the already formed macromolecules, but not with each other (semi-batch process). Thus, each macromolecule generated in such a process will contain one initiator core but no vinyl group. Then, the polydispersity index is quite low and decreases with / M /Mn l-i-l//. (ii) Alternatively, initiator and monomer molecules can be mixed instantaneously (batch process). Here, the normal SCVP process and the process shown above compete and both kinds of macromolecules will be formed. For this process the polydispersity index also decreases with/,but is higher than for the semi-batch process, M /Mn=Pn//. ... 

Methylene cyclopropene (5), the simplest triafulvene, is predicted to be of very low stability. From different MO calculations5 it has been estimated to possess only minor resonance stabilization ranging to 1 j3. Its high index of free valency4 at the exocyclic carbon atom causes an extreme tendency to polymerize, a process favored additionally by release of strain. Thus it is not surprising that only one attempt to prepare this elusive C4H4-hydrocarbon can be found in the literature. Photolysis and flash vacuum pyrolysis of cis-l-methylene-cyclopropene-2,3-dicarboxylic anhydride (58), however, did not yield methylene cyclopropene, but only vinyl acetylene as its (formal) product of isomerization in addition to small amounts of acetylene and methyl acetylene65 ... 

Relative humidity changes were measured with a nano-scale HRI-coated LPG in a wide range from 38.9% to 100% RH with a sensitivity of 0.2 nm/%RH, and an accuracy of 2.3% RH59. The material used was a hydro-gel layer composed by, among other chemicals, acrylic acid and vinyl pyridine. Fine adjust of the components proportion made possible to obtain a refractive index of the gel of about 1.55. The overlay thickness was estimated to be in that case 600 nm. 

A foamable composition nsefnl for rotational moulding is described, which advantageonsly inclndes an ethylene vinyl ester copolymer as an additive. The additive beneficially has a higher melt index than the base resin of the composition. 

Poly(vinyl butyral) has clarity and a refractive index similar to glass. It has good flexibility and adhesion to glass, even at low temperatures. It is used as safety glass interlining. 

Yu X, Yi B, Wang X (2007) Prediction of the refractive index of vinyl polymers by using density functional theory. J Comp Chem 28 2336-2341... 

The last property is related to the processing of the rubber in the tire making equipment. By using organo-lithium compound in this case, it was possible to maintain a vinyl content not greater than 18, but to produce a polybutadiene styrene copolymer that has random block styrene and without the use of polar modifiers, which normally will increase the 1,2 content. This copolymer, when compounded in the tread recipe, as shown in the Table XVI, gave properties that are actually equivalent to that of emulsion SBR and in some cases even better. This is particularly true in the properties of the Young modulus index, which showed between -38 to -54 C the Stanley London Skid Resistant, in which the control is 100, shows that 110-115 was obtained. 

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