Poly vinylchloride

Poly(vinylchloride). Cellular poly(vinyl chloride) can be produced from several expandable formulations as well as by decompression techniques. Rigid or flexible products can be made depending on the amount and type of plasticizer used (43). 

Poly(vinylchloride). Cellular poly(vinyl chloride) is prepared by many methods (108), some of which utili2e decompression processes. In all reported processes the stabili2ation process used for thermoplastics is to cool the cellular state to a temperature below its second-order transition temperature before the resia can flow and cause coUapse of the foam. 

Fig. 3. Effect of density on compressive modulus of rigid cellular polymers. A, extmded polystyrene (131) B, expanded polystyrene (150) C-1, C-2, polyether polyurethane (151) D, phenol—formaldehyde (150) E, ebonite (150) E, urea—formaldehyde (150) G, poly(vinylchloride) (152). To convert...

Packaging materials which have a smooth, impervious surface, free fi cm crevices or interstices, such as cellulose acetate, polyethylene, polypropylene, poly vinylchloride, and metal foils and laminates, all have a low surface microbial count. Cardboard and paperboard, unless treated, carry mould spores of Cladosporium spp., Aspergillus spp. md Penicillium spp. and bacteria such 2 Bacillus spp. sn.dMicrococcus spp. 

Polymer gels and ionomers. Another class of polymer electrolytes are those in which the ion transport is conditioned by the presence of a low-molecular-weight solvent in the polymer. The most simple case is the so-called gel polymer electrolyte, in which the intrinsically insulating polymer (agar, poly(vinylchloride), poly(vinylidene fluoride), etc.) is swollen with an aqueous or aprotic liquid electrolyte solution. The polymer host acts here only as a passive support of the liquid electrolyte solution, i.e. ions are transported essentially in a liquid medium. Swelling of the polymer by the solvent is described by the volume fraction of the pure polymer in the gel (Fp). The diffusion coefficient of ions in the gel (Dp) is related to that in the pure solvent (D0) according to the equation ... 

Among all the polymers used in preparing ion-selective membranes, poly(vinylchloride) (PVC) is the most widely used matrix due to its simplicity of membrane preparation [32, 70], In order to ensure the mobility of the trapped ionophore, a large amount of plasticizer (approximately 66%) is used to modify the PVC membrane matrix (approximately 33%). Such a membrane is quite similar to the liquid phase, because diffusion coefficients for dissolved low molecular weight ionophores are high, on the order of 10 7-10 8cm2/s [59],... 

Cerium Ce(IV) co-precipitation with ferric hydroxide, dissolution in hydrochloric acid, then passed through a column of bis (2 ethyl hexyl) phosphate on poly(vinylchloride), eluted with 0.3 M perchloric acid Spectrofluorimetry at 350 nm (excitation 255 nm) [626]... 

Examples of additives and polymer substrates which could react via [1) would be chlorinated paraffin waxes, hexabromocyclododecane (HBCD) and poly(vinylchloride) or poly(vinylbromide). 

For the formation of microgels the presence of a crosslinking monomer is not always necessary. Thus, microgels have also been detected in polymers prepared with bifunctional monomers, e.g. poly(acrylonitrile-co-vinylacetate) [39], polyethylene [40],poly(vinylchloride) [41] andpoly(vinylidenefluoride) [42].Obviously, the reason for the intramolecular crosslinking with the formation of microgels are side reactions. 

This category includes such polymers as atactic polystyrene (25-291 or poly(vinylchloride) (30.31 and references therein). A closely related problem is the gelation of non-block copolymers (5), which share with atactic polymers the feature that chemically and conformationally homogeneous sequences may be relatively short, so that when two or more chains interact, large crystalline domains are prevented from forming. 

As explained in Sections 16.3.4, 6.4.1, and 16.4.2, SEC is a nonabsolute method, which needs calibration. The most popular calibration materials are narrow molar mass distribution polystyrenes (PS). Their molar mass averages are determined by the classical absolute methods—or by SEC applying either the absolute detection or the previously calibrated equipment. The latter approach may bring about the transfer and even the augmentation of errors. Therefore, it is recommended to apply exclusively the certified well-characterized materials for calibrations. These are often called PS calibration standards and are readily available from numerous companies in the molar mass range from about 600 to over 30,000,000g moL. Their prices are reasonable and on average (much) lower than the cost of other narrow MMD polymers. Other available homopolymer calibration materials include various poly(acrylate)s and poly(methacrylate)s. They are, similar to PS, synthesized by anionic polymerization. Some calibration materials are prepared by the methods of preparative fractionation, for example, poly(isobutylene)s and poly(vinylchloride)s. 

Liu et al. prepared a procaine-sensitive FET transducer by coating a suitable electrode with sodium tetraphenylborate-procaine active material, 5% of poly(vinylchloride), and dibutyl phthalate in tetrahydrofliran [71]. The optimum operating pH was determined to be between 2 and 7. The transducer was applied in the potentiometric titrimetric determination of procaine in injection solution, where the recovery was 100.7% and the coefficient of variation (n = 2) was 1.4%. 

A poly (vinylchloride) membrane electrode was described for local anesthetics, based on dibenzo-24-crown-8 as the electroactive material, and di(2-ethyl)hexyl phthalate as the plasticizer [74]. It was reported that the electrode exhibited a Nemstian response to procaine, and other electrode properties were also presented. The analysis was performed at pH 6 to 6.5 vs. S.C.E., with a 0.2 M lithium acetate agar bridge. Less efficient crown ethers studied at this time were benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-30-crown-10. 

Separators used in lead-acid batteries are usually produced from synthetic polymers as sintered poly(vinylchloride) and extruded polyethylene, glass, or microglass fiber [203, 348, 354],... 

Films cast from poly(methylmethacrylate), poly(vinylidenefluoride), polyfbutylmethacrylate), and poly(vinylchloride)... 

CA 65, 2057(1966) [Exothermic compns useful as proplnts, expls, and incendiaries can be prepd by mixing powd Zn 30, powd NH4C1 20, powd AN 47 poly(vinylchloride) molding powd 3%, followed by heating to softening point and pressing into blocks. Addn of small amts of water to these mixts produces flame and hot gasesl... 

Succinylcholine chloride, hexamethonium bromide and decamethonium bromide were purchased from Sigma (St. Louis, MO). NPOE (2-nitrophenyloctyl ether)(Fluka) and poly(vinylchloride)(Aldrich)... 

Fig. 1 Fractionation of poly(vinylchlorides) using HPLC/GPC — Polyscience PVC VHMW Aldrich PVC solid line experimental Occidental Chemical Co. Suspension-polymerized PVC PD = polydispersity index = 2 (random distribution).

BPEI was cross-linked by /V-alkylation with poly(vinylchloride), producing a polymer whose chelating properties to copper(II) and mercury(II) depend on the concentration of secondary amino groups and on the ion concentration of the solution but do not depend on the pH in the range of 0-3 [85],... 

Fig. 3.7 Dielectric relaxation curves for poly(vinylchloride) in the a-relaxa-tion region. From Ishida (1960) with permission from Dr Dietrich Steinlcopff Vertag.

Fig. 3.11 The plasticising effect of diphenyl in poly(vinylchloride) dielectric loss curves at 60 Hz for (right to left) 0, 1, 3, 6, 9, 12, 15, 20% diphenyl. Reproduced from Fuoss (1941). Copyright of the American Chemical Society.

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