Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Monomers, vinyl containing

In order to increase the solubiUty parameter of CPD-based resins, vinyl aromatic compounds, as well as other polar monomers, have been copolymerized with CPD. Indene and styrene are two common aromatic streams used to modify cyclodiene-based resins. They may be used as pure monomers or contained in aromatic steam cracked petroleum fractions. Addition of indene at the expense of DCPD in a thermal polymerization has been found to lower the yield and softening point of the resin (55). CompatibiUty of a resin with ethylene—vinyl acetate (EVA) copolymers, which are used in hot melt adhesive appHcations, may be improved by the copolymerization of aromatic monomers with CPD. As with other thermally polymerized CPD-based resins, aromatic modified thermal resins may be hydrogenated. [Pg.355]

The paper-impregnation drying oven exhausts contain high concentrations (10—20% LEL) of alcohols and some resin monomer. Vinyl resins and melamine resins, which sometimes also contain organic phosphate fire retardants, may be used for air filters. The organic phosphates could shorten catalyst life depending on the mechanism of reduction of catalyst activity. Mild acid leaching removes iron and phosphoms from partially deactivated catalyst and has restored activity in at least one known case. [Pg.515]

As with polybut-l-ene and many other vinyl monomers that contain an asymmetric carbon, isotactic, syndiotactic and atactic stmctures may be drawn. Using co-ordination catalysts such as mixtures of cobalt chlorides, aluminium alkyls, pyridine and water high-1,2 (high vinyl) polymers may be obtained. One product marketed by the Japan Synthetic Rubber Company (JSR 1,2 PBD) is 91% 1,2, and 51-66% of the 1,2 units are in the syndiotactic state. The molecular mass is said to be several hundred thousand and the ratio MJM is in the range 1.7-2.6. [Pg.307]

The initiator can be a radical, an acid, or a base. Historically, as we saw in Section 7.10, radical polymerization was the most common method because it can be carried out with practically any vinyl monomer. Acid-catalyzed (cationic) polymerization, by contrast, is effective only with vinyl monomers that contain an electron-donating group (EDG) capable of stabilizing the chain-carrying carbocation intermediate. Thus, isobutylene (2-methyl-propene) polymerizes rapidly under cationic conditions, but ethylene, vinyl chloride, and acrylonitrile do not. Isobutylene polymerization is carried out commercially at -80 °C, using BF3 and a small amount of water to generate BF3OH- H+ catalyst. The product is used in the manufacture of truck and bicycle inner tubes. [Pg.1207]

An additive described as reducing the water loss and enhancing other properties of well-treating fluids in high-temperature subterranean environments consists of polymers or copolymers from N-vinyl lactam monomers or vinyl-containing sulfonate monomers. Organic compounds like lignites, tannins, and asphaltic materials are added as dispersants [175]. [Pg.52]

Polymer from N- Vinyl Lactams and Vinyl Sulfonates. A water-soluble polymer from N-vinyl lactam monomers or vinyl-containing sulfonate monomers... [Pg.244]

Two major approaches to the formation of materials of this type have involved the derivatization of preformed organic polymers with organometallic functions and the synthesis and polymerization of organometallic monomers that contain vinyl substituents For the transition metals, condensation polymerizations have also been investigated. However, the reactions have generally been conducted at elevated temperatures, and the resulting products have often not... [Pg.437]

A Japanese patent72) claims the synthesis of thermally stable copolymers by free-radical terpolymerization of dialkylstannyl dimethacrylates, glycidyl methacrylate and vinyl monomers (vinyl chloride, styrene, vinyl acetate, etc.). The products contain 0.5 to 30% tin and 0.05 to 7 % epoxide oxygen. [Pg.120]

We can incorporate short chain branches into polymers by copolymerizing two or more comonomers. When we apply this method to addition copolymers, the branch is derived from a monomer that contains a terminal vinyl group that can be incorporated into the growing chain. The most common family of this type is the linear low density polyethylenes, which incorporate 1-butene, 1-hexene, or 1-octene to yield ethyl, butyl, or hexyl branches, respectively. Other common examples include ethylene-vinyl acetate and ethylene-acrylic acid copolymers. Figure 5.10 shows examples of these branches. [Pg.111]

Fluorinated polymers, especially polytetrafluoroethylene (PTFE) and copolymers of tetrafluoroethylene (TFE) with hexafluoropropylene (HFP) and perfluorinated alkyl vinyl ethers (PFAVE) as well as other fluorine-containing polymers are well known as materials with unique inertness. However, fluorinated polymers with functional groups are of much more interest because they combine the merits of pefluorinated materials and functional polymers (the terms functional monomer/ polymer will be used in this chapter to mean monomer/polymer containing functional groups, respectively). Such materials can be used, e.g., as ion exchange membranes for chlorine-alkali and fuel cells, gas separation membranes, solid polymeric superacid catalysts and polymeric reagents for various organic reactions, and chemical sensors. Of course, fully fluorinated materials are exceptionally inert, but at the same time are the most complicated to produce. [Pg.91]

No by-product is formed. The product has the same elemental composition as that of the monomer. The bifunctionality is provided by the double bond present in the monomer. Compounds containing reactive double bonds can undergo this type of reactions. Typical examples are vinyl compounds (CH2 = CHX),... [Pg.5]

Cationic polymerisation involves carbonium ion active species and takes place with monomers which contain electron releasing substituents such as phenyl, vinyl, alkoxy and 1, 1 dialkyl. [Pg.234]

Porous materials used for chromatography result from a chemically induced phase separation using chain-wise polymerization of vinyl-containing monomers crosslinked with a portion of divinyl functional monomers. Frechet has improved this technique for the preparation of porous PS beads [48]. In this approach the inner phase consists of a mixture containing the reactive styrene and divinylbenzene monomers as well as an unreactive polymeric porogen. After polymerization, the soluble polymeric porogen is removed, leaving behind ma-croporous beads with pore sizes of around 100-500 nm. [Pg.168]

Using the grafting-from method with NMP requires the synthesis and (co)polymerization of monomers that contain the nitroxide group [Hawker et al., 2001]. A halogen-containing monomer such as vinyl chloroacetate or p-chloromethylstyrene is reacted with an HO-containing alkoxyamine to yield a vinyl alkoxyamine, which is used as a NMP initiator to... [Pg.757]

Copolymerization. Vinyl chloride can be copolymerized with a variety of monomers. Vinyl acetate, the most important commercial comonomer, is used to reduce crystallinity, winch aids fusion and allows lower processing temperatures. Copolymers are used in flooring and coatings. This copolymer sometimes contains maleic add or vinyl alcohol (hydrolyzed from the poly(vinyl acetate ) to improve the coating s adhesion to other materials, including metals, Copolymers with vinylidene chloride are used as barrier films and coatings. Copolymers of vinyl chlonde with acrylic esters in latex from are used as film formers in paint, nonwoven fabric binders, adhesives, and coatings. Copolymers with olefins improve thermal stability and melt flow, but at some loss of heat-deflection temperature,... [Pg.1687]

Among all remaining monomers, those containing (per)fluorinated side chains such as fluorinated acrylates, vinyl ethers or esters, maleimides and styrenic monomers are also very interesting and have been studied in (co)telo-merisation. Most of them have been previously reviewed [15]. However, they are not mentioned in this chapter. [Pg.207]

Under the same reaction conditions, catalytic activity is greater for cryptands than crown ethers or quaternary onium salts (111, 113). A series of polymer cryptands derived from the vinyl-containing monomer 16 have been discussed and could well find useful application (114). [Pg.20]

In the above-mentioned patents post-polymerization modification is performed in a single step. An alternative is the performance of two sequential modification steps. In the first step the polymer is reacted with tin or germanium derivatives (triphenyl tin, tributyl tin, diphenyl tin dichloride, dioctyl tin dichloride, phenyl tin trichlorde etc.). In the subsequent modification step heterocumulene compounds (ketenes, thioketenes, isocyanates, thioiso-cyanates and carbodiimides) are applied [437,438]. Specific interaction with silica is obtained by end group functionalization with vinyl monomers which contain hydroxyl or epoxy groups. The effects are observed if the PDI is below 5 [439,440]. [Pg.67]

Vinyl polymer (Section 24.1) An addition polymer that is prepared from a monomer that contains a vinyl group. [Pg.1277]

Copolymerization of VAc with Various Comonomers. The monomer mixtures used in our experiments were VAc as monomer Mi and AN, AA, MAA, acrylamide (AAm), maleic acid (MA), and fumaric acid (FA) as monomer M2 (33). All the ESR spectra obtained from the binary monomer systems containing vinyl ester and small amounts of M2... [Pg.155]

Awareness of the problem developed in the mid 1970s when it was found that mineral waters sold in polyvinyl chloride (PVC) bottles contained measurable amounts of vinyl chloride monomer. Vinyl chloride is a known carcinogen. The Codex Alimentarius Committee on Food Additives and Contaminants has set a guideline of 1 ppm for vinyl chloride monomer in PVC packaging and 0.01 ppm of the monomer in food (Institute of Food Technologists 1988). Another additive found in some PVC plastics is octyl tin mer-captoacetate or octyl tin maleate. Specific regulations for these chemicals exist in the Canadian Food and Drugs Act. [Pg.341]

There are a few examples of polymers based on vinylbenzofurans. Vinyldibenzofuran 324 has been patented for use in copolymer formulations with other vinyl arenes, used to prepare light-emitting devices <2004USP6803124>. Benzofuran 325 was developed as one of four polymerizable monomers that contain a built-in antioxidant. The polymerization process was transition metal catalyzed <2003MM8346>. Benzofuran 326 also contains the styrene substructure, but there are few examples of its polymerization. Poly(2,3-benzofuran) films were synthesized by anodic oxidation on stainless steel in the presence of boron trifluoride etherate. The films had good thermal stability and conductivity of lO Scm <2005MI1654>. [Pg.611]

This chapter deals with the cationic polymerization of heterocyclic monomers, i.e., cyclic compounds containing one or more (identical or different) heteroatoms within the ring. Polymerization proceeds by a ring-opening reaction. Traditionally, this subject is discussed separately from the cationic polymerization of alkenyl monomers (vinyl polymerization) proceeding by opening of a double bond. This is justified, because both processes have their special features, making them distinctly different. [Pg.437]

H NMR spectroscopic studies have shown, that the obtained polymers contain the starting monomers vinyl acetate and ethoxysilane in the ratio of about 5 1. Molecular weight determination of the products... [Pg.609]


See other pages where Monomers, vinyl containing is mentioned: [Pg.463]    [Pg.502]    [Pg.320]    [Pg.364]    [Pg.56]    [Pg.450]    [Pg.21]    [Pg.45]    [Pg.46]    [Pg.9]    [Pg.508]    [Pg.4]    [Pg.320]    [Pg.7]    [Pg.4]    [Pg.25]    [Pg.100]    [Pg.1582]    [Pg.463]    [Pg.195]    [Pg.201]    [Pg.1263]    [Pg.1207]    [Pg.572]   
See also in sourсe #XX -- [ Pg.201 ]




SEARCH



Addition ferrocene-containing vinyl monomer

Phenol containing vinyl monomers, radical polymerization

Vinyl monome

Vinyl monomer

Vinyl monomer-containing polymer

Vinylic monomers

© 2024 chempedia.info