Copolymers oxide

Oxidation of mixtures of 2,6-disubstituted phenols leads to linear poly(arylene oxides). Random copolymers are obtained by oxidizing mixtures of phenols. Block copolymers can be obtained only when redistribution of the first polymer by the second monomer is slower than polymerization of the second monomer. Oxidation of a mixture of 2,6-di-methylphenol (DM ) and 2fi-diphenylphenol (DPP) yields a random copolymer. Oxidation of DPP in the presence of preformed blocks of polymer from DMP produces either a random copolymer or a mixture of DMP homopolymer and extensively randomized copolymer. Oxidation of DMP in the presence of polymer from DPP yields the block copolymer. Polymer structure is determined by a combination of differential scanning calorimetry, selective precipitation from methylene chloride, and NMR spectroscopy. 

The properties of such apparently soluble materials differed greatly from those containing stabilized polyacetylene crystallites. Attempts to dope the soluble copolymers yielded materials with low conductivities, and chemistry typical of solution chemistry (bromination) was observed rather than the formation of a stable bromine-doped polyacetylene phase. A poly(isoprene-fo-acetylene) copolymer oxidized with iodine gave conductivities as high as 1-10 S/cm, but the characterization of the copolymer was insufiScient to unambiguously identify it as a soluble copolymer. On the basis of previously reported work, this material is likely to correspond to a stabilized suspension rather than a solution. 

Synonyms Ethylene vinyl acetate copolymer, oxidized Uses Coatings ingted. 

Ethylene vinyl acetate Ethylene/vinyl acetate copolymer. See Ethylene/VA copolymer Ethylene vinyl acetate copolymer, oxidized. See Ethylene/VA copolymer, oxidized Ethylene/vinyl acetate/vinyl alcohol copolymer CAS 26221-27-2 Uses Food pkg. 

Vinyl bromide coatings ingredient EthyleneA/A copolymer, oxidized coatings modifier, hot-melt 1,4-Cyclohexanedimethanol dibenzoate ... 

Octadecene/MA copolymer Oxidized cellulose PEG-6 cocamide PEG-12 dilaurate PEG-12 dioleate... 

EthyleneA/A copolymer, oxidized 104934-17-0 Nikkol Hexaglyn 5-0 Polyglyceryl-6 pentaoleate 104986-28-9 Berryflor... 

Vinyl acetate monomer (VAM) is broadly used for the manufacture of polyvinyl acetate (PVAc), polyvinyl alcohol (PVAl) and ethylene-vinyl acetate (EVA)-, vinyl acetate-acrylic-, vinyl chloride-vinyl acetate (VC/VAc)-, and vinyl pyrroHdone-vinyl acetate (V p/VAc)-copolymers, oxidation to yield ethylene oxide (EO) ... 

The elastomers are compounded with antioxidants to prevent thermal and photo-oxidation, which can be initiated through the unsaturated zones in the copolymers.Oxidation can take place during melt processing and during the life of the fabricated product. Phe-... 

EVA copolymers oxidize in the jS-position with respect to the acetyl groups. In thermal oxidation a polyene chain appears, while in photooxidation cross-linking by C — O — C bonds is also possible [99-101]. 

To find out why the N,N-dichlorosulfonamide copolymer, oxidizes the nitrite ion in neutral and medium acidic solution smoothly, whereas in the alkaline solution with difficulty only, the copolymer was subjected to a redox titration by means of 0.01 M NaN02 in three different media (a) distilled water, (b) 0.01 M acetic acid, (c) 0.01 M NaOH (Fig.2a). 

Waterproofing, whether it has to do with protecting civil engineering structures or roofs or terraces. Poured asphalt, often placed in layers with kraft paper, oxidized bitumen or modified bitumen can be used, generally with copolymer. The modified bitumen are used for the making prefabricated multi-layer waterproofing composites. 

Fig. 6. Snapshot from a dynamic density functional simulation of the self-organisation of the block copolymer PL64 (containing 30 propylene oxide rmd 26 ethylene oxide units (EO)i3(PO)3o(EO)i3) in 70% aqueous solution. The simulation was carried out during 6250 time steps on a 64 x 64 x 64 grid (courtesy of B.A.C. van Vlimmeren and J.G.E.M. Praaije, Groningen).

The method has severe limitations for systems where gradients on near-atomic scale are important (as in the protein folding process or in bilayer membranes that contain only two molecules in a separated phase), but is extremely powerful for (co)polymer mixtures and solutions [147, 148, 149]. As an example Fig. 6 gives a snapshot in the process of self-organisation of a polypropylene oxide-ethylene oxide copolymer PL64 in aqueous solution on its way from a completely homogeneous initial distribution to a hexagonal structure. 

Polylphenylene oxide) Styrene-ethylene block copolymer... 

Copolymer. Acetal copolymers are prepared by copolymerization of 1,3,5-trioxane with small amounts of a comonomer. Carbon-carbon bonds are distributed randomly in the polymer chain. These carbon-carbon bonds help to stabilize the polymer against thermal, oxidative, and acidic attack. 

This situation can be generalized. If the ratios do not become constant until the ratio of pentads to tetrads is considered, then the unit before the next to last-called the antepenultimate unit-plays a role in the addition. This situation has been observed for propylene oxide-maleic anhydride copolymers. 

Materials that typify thermoresponsive behavior are polyethylene—poly (ethylene glycol) copolymers that are used to functionalize the surfaces of polyethylene films (smart surfaces) (20). When the copolymer is immersed in water, the poly(ethylene glycol) functionaUties at the surfaces have solvation behavior similar to poly(ethylene glycol) itself. The abiUty to design a smart surface in these cases is based on the observed behavior of inverse temperature-dependent solubiUty of poly(alkene oxide)s in water. The behavior is used to produce surface-modified polymers that reversibly change their hydrophilicity and solvation with changes in temperatures. Similar behaviors have been observed as a function of changes in pH (21—24). 

The many commercially attractive properties of acetal resins are due in large part to the inherent high crystallinity of the base polymers. Values reported for percentage crystallinity (x ray, density) range from 60 to 77%. The lower values are typical of copolymer. Poly oxymethylene most commonly crystallizes in a hexagonal unit cell (9) with the polymer chains in a 9/5 helix (10,11). An orthorhombic unit cell has also been reported (9). The oxyethylene units in copolymers of trioxane and ethylene oxide can be incorporated in the crystal lattice (12). The nominal value of the melting point of homopolymer is 175°C, that of the copolymer is 165°C. Other thermal properties, which depend substantially on the crystallization or melting of the polymer, are Hsted in Table 1. See also reference 13. 

Chemical Structure and Properties. Homopolymer consists exclusively of repeating oxymethylene units. The copolymer contains alkyhdene units (eg, ethyUdene —CH2—CH2—) randomly distributed along the chain. A variety of end groups may be present in the polymers. Both homopolymer and copolymer may have alkoxy, especially methoxy (CH3 O—), or formate (HCOO—) end groups. Copolymer made with ethylene oxide has 2-hydroxyethoxy end groups. Homopolymer generally has acetate end groups. 

Thermal Oxidative Stability. ABS undergoes autoxidation and the kinetic features of the oxygen consumption reaction are consistent with an autocatalytic free-radical chain mechanism. Comparisons of the rate of oxidation of ABS with that of polybutadiene and styrene—acrylonitrile copolymer indicate that the polybutadiene component is significantly more sensitive to oxidation than the thermoplastic component (31—33). Oxidation of polybutadiene under these conditions results in embrittlement of the mbber because of cross-linking such embrittlement of the elastomer in ABS results in the loss of impact resistance. Studies have also indicated that oxidation causes detachment of the grafted styrene—acrylonitrile copolymer from the elastomer which contributes to impact deterioration (34). 

Examination of oven-aged samples has demonstrated that substantial degradation is limited to the outer surface (34), ie, the oxidation process is diffusion limited. Consistent with this conclusion is the observation that oxidation rates are dependent on sample thickness (32). Impact property measurements by high speed puncture tests have shown that the critical thickness of the degraded layer at which surface fracture changes from ductile to brittle is about 0.2 mm. Removal of the degraded layer restores ductiHty (34). Effects of embrittled surface thickness on impact have been studied using ABS coated with styrene—acrylonitrile copolymer (35). 

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