Polyvinyl chloride, viscosity

The paper discusses the application of dynamic indentation method and apparatus for the evaluation of viscoelastic properties of polymeric materials. The three-element model of viscoelastic material has been used to calculate the rigidity and the viscosity. Using a measurements of the indentation as a function of a current velocity change on impact with the material under test, the contact force and the displacement diagrams as a function of time are plotted. Experimental results of the testing of polyvinyl chloride cable coating by dynamic indentation method and data of the static tensile test are presented. 

P.V.C. plastisols P.V.C. plastisols are liquids which contain little or no solvent/diluent. They consist of a blend of polyvinyl chloride (p.v.c.) resins, plasticisers, stabilisers, viscosity depressants, pigments and sometimes fillers. 

When two polymers interact or react with each other, they are likely to provide a compatible, even a miscible, blend. Epoxidized natural rubber (ENR) interacts with chloro-sulfonated polyethylene (Hypalon) and polyvinyl chloride (PVC) forming partially miscible and miscible blends, respectively, due to the reaction between chlorosulfonic acid group and chlorine with epoxy group of ENR. Chiu et al. have studied the blends of chlorinated polyethylene (CR) with ENR at blend ratios of 75 25, 50 50, and 25 75, as well as pure rubbers using sulfur (Sg), 2-mercapto-benzothiazole, and 2-benzothiazole disulfide as vulcanizing agents [32]. They have studied Mooney viscosity, scorch... 

Figure 2. Intrinsic viscosity-molecular weight data for polystyrene and polyvinyl chloride measured by osmometry and by SEC using broad MWD standard calibration (polystyrene (m) M = 7,06 X 10 in THF/1% PPG (O) [ ] =...

The plasticizer-range alcohols are largely used as feedstock for production of high molecular weight diesters of phthalic, adipic, azelaic, and sulftiric acids. All these are used primarily in plasticizers for polyvinyl chloride (PVC) and other plastics. The plastics industry also uses them as additives for heat stabilization, to control the viscosity of PVC plastisols, ultraviolet absorbers, flame retardants, and antioxidants. They are also found in synthetic, lubricants, agricultural chemicals, and defoamers. 

Figure J. Viscosity stability of polyvinyl chloride-o-pkthalate ester compositions...

Another very important property of plasticizers for PVC resins is the ability to act as a dispersing medium for polyvinyl chloride plastisols. The performance of the particular plasticizer in a plastisol application depends to a great extent on a property known as its viscosity stability. The stability of the plastisol to viscosity build up is the manifestation of the solvating effects of the plasticizer, and thus, those materials with higher solvating efficiency tend to display an increase in plastisol viscosity on standing. Figure 3 is the plot of the viscosity stability of PVC o-phthalate ester plastisol compositions and, in essence, compares the alcohol-derived plasticizers with that of the olefin-derived plasticizer. The data show that... 

Other Plasticizers. Acetyl tributyl citrate is an outstanding nontoxic plasticizer for polyvinyl chloride in food packaging Plastisol formulations containing this ester have exceptional viscosity stability. Acetyl triethyl citrate is a good plasticizer for the cellulosics and acetyl trioctyl citrate shows promise with vmylidene chloride polymers. Other compounds of diverse nature find application as plasticizers. These include tetra-w-butyl thiodisuceinate, camphor, o-nitrobiphenyl and partially hydrogenated isomeric terphenyls... 

As the shear rate increases, the viscosity of some dispersions actually increases. This is called dilatancy, or shear-thickening. Dilatancy can be due to the dense packing of particles in very concentrated dispersions for which at low shear, the particles can just move past each other but at high shear they become wedged together such that the fluid cannot fill (lubricate) the increased void volume, and the viscosity increases. An example of this effect is the apparent drying of wet beach sand when walked on, the sand in the footprint initially appears very dry and then moistens a few seconds later. Other examples include concentrated suspensions (plastisols) of polyvinyl chloride (PVC) particles in plasticizer liquid and the commercial novelty product Silly Putty (which is a silicone material). 

G 7 Guzman, G. M., and J. M. G. Fatou Configurational properties of polyvinyl chloride by viscosity and light scattering measurements. Anales real. soc. espafi. fis. y quim. 55 B, 129 (1959). 

VISCOSITY CHANGES ASSOCIATED WITH THE CHEMICALLY INDUCED CROSSLINKING OF PLASTICISED POLYVINYL CHLORIDE MEASURED BY PARALLEL PLATE TORQUE RHEOMETRY INFLUENCE OF MAGNESIUM AND BARIUM MERCAPTIDES Rosales-Jasso A Arias G Rodriguez O S Allen N S Centro de Investigacion en Quimica Aplicada Manchester,Metropolitan University... 

FIGURE 12.16 Shear thickening found by Hoffman [47] for 1.25 pm diameter polyvinyl chloride (PVC) latex particles in di-2-ethylhexyl phtiialate with the discontinuous dependence of viscosity on shear rate. Redrawn fi m Hofhnan [49]. 

The chemicals used for coating and laminating are polymeric materials, either naturally occurring or produced synthetically. These include natural and synthetic rubbers, polyvinyl chloride, polyvinyl alcohol, acrylic, phenohc resins, polyurethanes, silicones, fluorochemicals, epoxy resins and polyesters." Coating formulations typically include auxiliaries such as plasticizers, adhesion promoters, viscosity regulators, pigments, fillers, flame retardants, catalysts and the like. ... 

Several systems can show shear thickening, such as wet sand, com starch dispersed in milk and some polyvinyl chloride sols. Shear thickening can be illustrated when somebody walks on wet sand such that some water is squeezed out and the sand appears dry. The deformation applied by the feet causes a rearrangement of the close-packed stracture produced by the water motion, and this process is accompanied by a volume increase (hence the term dilatancy) as a result of sucking in of the water. The process amounts to a rapid increase in the viscosity. 

In their processible mixture, these one-component products, also belonging to physically setting adhesives, consist of two components PVC (polyvinyl chloride-) particles and plasticizers (Section 9.2.9). The solid PVC particles are disperged in the high-viscosity plasticizer. The adhesive layer formation occurs by heating (120-180 °C), when the thermoplastic PVC swells and is thus able to absorb the plasticizer (no chemical reaction ). This process is called a sol-gel process. The formerly two-phase system (sol) is turned into a single-phase system (gel) by the inclusion of the plasticizer. 

Soluble acetate, Fortisan slowly, Amel, Dynel, nylon Dacron in warm phenol vinyon and polyvinyl chloride (Rhovyl) in boiling phenol viscose. 

FIGURE 4.25 Temperature dependence of polyvinyl chloride solution viscosity on temperature in three different solvents. 

FIGURE 4.26 Schematic of viscosity change of polyvinyl chloride slurry in acetone-benzene with time. 

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