Polyvinylchloride molecular weight

In the United States high molecular weight polyethylene is used, and in the United Kingdom, cross-linked polyethylene with polyvinylchloride is used. 

The second method assumes that the molecular weight calibration curve is linear on a semilog plot and should be employed where universal calibration is not practical as with aqueous SEC. Several variants of these methods involving different molecular weight data for the standards are discussed. The proposed methods have been evaluated using aqueous SEC and polydextran standards and nonaqueous SEC with polyvinylchloride standards. 

The Q-factor approach is based upon the weight-to-size ratios (Q-factors) of the calibration standard and the polymer to be analyzed. The Q-factors are employed to transform the calibration curve for the chemical type of the standards (e.g. polystyrene) into a calibration curve for the chemical type of polymer under study. The inherent assumption In such a calibration approach is that the weight-to-size ratio is not a function of molecular weight but a constant. The assumption is valid for some polymer types (e.g. polyvinylchloride) but not for many polymer types. Hence the Q-factor method is generally referred to as an approximation technique. 

Sample Materials. Vinnol H 60d. Vinnol Y 60, and Vinnol E 6Qg are commercial polyvinylchlorides from Wacker. produced by suspension, bulk, and emulsion polymerization techniques, respectively. All materials have nearly the same molecular weight distribution (MWD) as Solvlc 226 which, (with our SEC calibration) gave M = 74.000, M = 35,000. The samples used in this investigation in the Vinnol 60 series had molecular weights in the range M = 72,000 2000 and... 

This chlorine atom attack accounts for the decrease in the molecular weight of polymethylmethacrylate, monomer production at abnormally low temperature and the delay in the dehydrochlorination of polyvinylchloride. This delay in dehydrochlorination is general for blends of polyvinylchloride and any polymer containing hydrogen atoms that can be abstracted by chlorine atoms. 

Polyvinylchloride (PVC) (Continued) Molecular weight, 59 Number-average molecular weight, 59 Photodegradation, 60 Plastisized, 59 Rigid, 70... 

Acrylonitrile-butadiene rubber, NBR, styrene-aciylonitrile rubber, SAN, ethylene-vinyl acetate copolymer, EVA, and acrylic copolymers are helpful modifications of polyvinylchloride that change its processing characteristics and elastomeric properties. Blending with these copolymers helps to reduce the requirement for low molecular weight plasticizers. Ethylene-vinyl acetate copolymer plays a role of high molecular weight plasticizer in production of vinyl hose. This reduces the amount of DOP used in flexible hose applications. Ethylene copolymer is used plasticize PVC that reduces gel. "" Phthalate plasticizers can be eliminated from water based adhesives because of utilization of vinyl acetate ethylene copolymer as a high molecular plasticizer/modifier. " ... 

Polyvinylchloride, PVC. PVC was commercialized in 1931 when its plasticization was developed. However, owing to the low molecular weight nature of the plasticizers, they tend to migrate to the surface and evaporate, which causes premature brittleness. Over the years, several types of polymeric modifiers were discovered acrylic, elastomeric, chlorinated polyolefins, vinylic, and their copolymers and/or mixtures, e.g., ABS, MBS, SMA. Since most of these materials were polymerized in aqueous media, latex blending was the natural early method. 

Polystyrene macromonomers [41] with molecular weights of 10 -lO were also prepared. Similar experiments [42,43] using 2-mercaptoethanol, and subsequent treatment of the resulting polymer with methacrolyl chloride led to methacryl end-capped polymethacrylates and polyvinylchloride. Typical reactions in the case of polyvinylchloride are illustrated in Scheme 12. 

SOLSPERSE 3000, a hyperdispersant originally developed for the dispersion of titanium dioxide in airdrying paints [5], was identified as showing benefit in the processing of rigid Polyvinylchloride compound. In the case of the Polyethylene masterbatch study, a novel hyperdispersant, SOLPLUS DP310 was developed. This hyperdispersant optimizes both the polymer chain chemistry and the molecular weight to achieve effective dispersion. 

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