Polyfvinyl chloride PVC

Rigid polyfvinyl chloride) (PVC) compounds and chlorinated poly(vinyl chloride) (CPVC) compounds... 

Polyfvinyl chloride) (PVC) is produced by mass, suspension, and emulsion processes. Mass polymerization is an exatiiple of a heterogeneous bulk system. PVC is virtually insoluble in vinyl chloride because the polymer is about 35% more dense than the monomer under normal polymerization conditions. Vinyl chloride, however, is quite soluble in polymer. The two phases in PVC polymerizations are pure monomer and monomer-swollen polymer. Polymerization proceeds in both phases, but it is very much faster in the polymer-rich phase because the mobility of macro radicals and mutual termination reactions are. severely restricted (cf. Section 6.13.2). 

Polyfvinyl chloride) (PVC), which becomes rubbery after blending with sufficient of a suitable plasticizer. 

The broadening of the dielectric spectra for miscible polymer blends is not only observed for the PS/PVME system. This further demonstrated by Fig. 12.16 where the normalized dielectric loss is plotted for a blend poly(ethylene-co-vinyl acetate) (EVA70, 70 % vinyl acetate) with polyfvinyl chloride) (PVC). With increasing concentration of PVC in the blend, the loss peak systematically broadens in comparison to that of both components (Rellick and Runt 1988). 

Vinidur Polyfvinyl chloride), PVC, and impact-modified PVC with 5-15 wt% acrylate-graft copolymer BASF Plastics... 

When a plasticizer is blended into a polymer, the glass transition temperature (Tg) of the polymer decreases. The variation Tg for a mixture of polyfvinyl chloride) (PVC) and dioctyl phthalate... 

To accelerate the diffusion rate and shorten the time for the formation of gas/polymer solutions, we must raise the temperature and shorten the diffusion distance. This is done by deforming the two-phase mixture of polymer and gas through shear distortion to decrease the diffusion path. This type of deformation occurs in an extruder under laminar-flow conditions. The bubbles are stretched by the shear field of the two-phase mixture and eventually break up to minimize the surface energy when a critical Weber number is reached (4). The disintegrated bubble size is calculated to be about 1 mm and the initial striation thickness after bubble disintegration is calculated to be about twice the bubble diameter (5). This striation thickness decreases with further shear, and the gas diffusion occurs faster as a result of the increase in the surface area and the decrease in striation thickness. The striation thickness in an extruder is estimated to decrease to about 100 /xm. At this thickness, the diffusion time is about 1 min in PET, from 10 to 20 s in polystyrene (PS), polyfvinyl chloride) (PVC), and high density polyethylene (HDPE), and in the range of a few seconds in low density polyethylene (LDPE). 

Figure 11.26 The relationship between AK and fatigue crack growth rates for poly(methyl methacrylate), PMMA polysulfone, PSF polystyrene, PS polyfvinyl chloride), PVC poly(2,6-dimethyl-1,4-phenylene oxide), PPO polycarbonate, PC nylon 66 and polyfvinylidene fluoride), PVp2 (49). Samples with data to the right are more fatigue resistant than on the left, because they require higher levels of stress at the crack tip to propagate the crack.

Molecular weights are not often measured directly for control of production of polymers because other product properties are more convenient experimentally or are thought to be more directly related to various end uses. Solution and melt viscosities are examples of the latter properties. Polyfvinyl chloride) (PVC) production is controlled according to the viscosity of a solution of arbitrary concentration relative to that of the pure solvent. Polyolefin polymers are made to specific values of a melt flow parameter called melt index, whereas rubber is characterized by its Mooney viscosity, which is a different measure related more or less to melt viscosity. These parameters are obviously of some practical utility, or they would not be used so extensively. They are unfortunately specific to particular polymers and are of little or no use in bringing experience with one polymer to bear on problems associated with another. 

Because titanium ignites spontaneously in dry chlorine, it must be avoided. Graphite, glass, and glazed porcelain are used where there is a risk of moisture in the dry chlorine gas, and polyfvinyl chloride) (PVC) or chlorinated PVC and polyester resins are suitable if the temperature limits of these materials are regarded. 

Polsoirea, 99 Polsoirethane, 99 Poly(vinyl acetate), 199, 200 Poly(vinyl alcohol) (PVA), 9,20,94-5, 108, 110, 200, 202, 204, 258-9 analysis of dynamics, 261-2 aqueous system, 58 C CP/MAS NMR spectrum, 259-61 crosslink structure, 259-61 Poly(vinyl alcohol) (PVA)/sodium borate, self-correlation function, 205 Polyfvinyl alcohol) (PVA)-water gel, 57 Polyfvinyl chloride) (PVC), 109, 324 Poly(vinyl methylether) (PVME), 108, 245 Porod law, 212 Porod region, 196 Proportionality equations, 127 Protein gels, 288-90 Proteins, 282... 

The first completely synthetic plastic, phenol-formaldehyde, was introduced by L. H. Baekeland in 1909, nearly four decades after J. W. Hyatt had developed a semisynthetic plastic—cellulose nitrate. Both Hyatt and Baekeland invented their plastics by trial and error. Thus the step from the idea of macromolecules to the reality of producing them at will was still not made. It had to wait till the pioneering work of Hermann Staudinger, who, in 1924, proposed linear molecular structures for polystyrene and natural rubber. His work brought recognition to the fact that the macromolecules really are hnear polymers. After this it did not take long for other materials to arrive. In 1927 polyfvinyl chloride) (PVC) and cellulose acetate were developed, and 1929 saw the introduction of urea-formaldehyde (UF) resins. 

The most efficient way is to store the samples deep-frozen immediately after sampling, using polyethylene or polycarbonate containers. Under this condition, TBT was shown to be stable for 2-3 months. Polytetrafluoroethylene (PTFE) as the container material was shown to cause species loss, most probably owing to the porosity of this material. Polyfvinyl chloride) (PVC) bottles must be ruled out as container material, because PVC contains TBT for UV stabilisation which has been found to leach out of PVC containers and also from PVC tubes used for water supply. Several reviews on this topic can be found. ... 

The IR spectra of ethylene (E)-vinyl (V) chloride has revealing information. These copolymers were prepared by partial reduction of polyfvinyl chloride) (PVC) with tri-n-butyltin hydride [9]. During the reduction of PVC, the reaction rate of tri- -but-yltin hydride with the V units depends on the dyad-triad environment of the V unit, with the central unit in the P3(VW) being more reactive than the central unit in the Ps(EVE). The mono-ad, dyad and triad probabilities obtained from NMR data for the E-V copolymers are shown in Table 4.1. These results are plotted in Fig. 4.8 for length sequences of 1, 2, 3,4,5 and 10. 

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