Blends of poly vinyl chloride

PVC with chlorinated polyethylene blends has improved impact performance, especially in the presence of notches and at lower temperatures than unmodified grades of PVC. They are used in continental Europe for external applications (e.g. rainwater goods) unmodified UPVC would be acceptable in the UK. Such blends are finding increasing use throughout Europe in extruded sections for window frames. 

PVC blended with ABS or impact-modified PMMA has improved processability and good fire resistance, along with impact properties superior to those of the parent polymers. ABS/PVC is used as calendered sheet thermoformed into car crash-pad skins (subsequently back-filled with semirigid PU foam), also in moulded power tool handles, sanitaryware and electrical housings. Impact PMMA/PVC is used for seat backs for public transport and industrial panelling. 

PPVC is blended with high-molecular-weight elastomeric materials, such as nitrile rubber (NBR), EVAC and polyurethane (PU), to improve the shock resistance of flexible compounds. PPVC/NBR blends have good oil resistance and are used to make industrial boot-soles and in some electrical cable applications. PVC/EVAC and PVC/PU are used in shoe-sole formulations. 

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Blends of poly(vinyl chloride) (PVC) and a-methylstyrene—acrylonitrile copolymers (a-MSAN) exhibit a miscibiUty window that stems from an LCST-type phase diagram. Figure 3 shows how the phase-separation temperature of 50% PVC blends varies with the AN content of the copolymer (96). This behavior can be described by an appropriate equation-of-state theory and interaction energy of the form given by equation 9. 

Physical Properties of Blends of Poly(vinyl Chloride) and a Terpolymer of Ethylene... 

The compatibility of blends of poly (vinyl chloride) (PVC) and a terpolymer (TP) of ethylene, vinyl acetate, and carbon monoxide was investigated by dynamic mechanical, dielectric, and calorimetric studies. Each technique showed a single glass transition and that transition temperature, as defined by the initial rise in E" at 110 Hz, c" at 100 Hz, and Cp at 20°C/min, agreed to within 5°C. PVC acted as a polymeric diluent which lowered the crystallization temperature, Tc, of the terpolymer such that Tc decreased with increasing PVC content while Tg increased. In this manner, terpolymer crystallization is inhibited in blends whose value of (Tc — Tg) was negative. Thus, all blends which contained 60% or more PVC showed little or no crystallinity unless solvent was added. 

Alsalhy, Q. F. 2012. HoUow fiber nltrafiltrahon membranes prepared from blends of poly (vinyl chloride) and polystyrene. Desalination 294 44—52. 

In a recent study by Work (1972fc) on blends of poly(vinyl chloride) with chlorinated polyethylene, some of the predictions discussed above have been... 

High-impact poly (vinyl chloride), A blend of poly(vinyl chloride) with an impact modifier. 

Isothermal aging experiments have been used to determine phase behavior in several systems. Blends of poly(vinyl chloride), PVC, (Tg = 80 °C) and poly (isopropyl methaciylate), PiPMA, (Tg = 82.5 °C), are believed to be immiscible, but because of the closeness of the Tg values, this is difficult to confirm. A 50/50 blend was annealed first at 195 °C, to erase previous thermal history, then quenched to 60 °C, i.e., (Tg - T ) 20 °C, and aged for various times (Bosma et al. 1988). 

The surfaces of polymeric blends of poly vinyl chloride and poly ethylene terephthalate have been treated by Kureshi et al. (Qureshia et al., 2007) with reactive (Nj+) gas plasma to understand the effects of low energy ions on the surface modification of polymeric blends. These effects were determined by microhardness tester, TGA/DSC analysis, and morphology study by atomic force microscope (AFM). Figure 14.24 shows the plot of Vickers microhardness (Hv) versus applied load (P) for pristine and plasma treated samples. 

This method of classification is useful for pure polymer samples without significant modification or in the absence of additives. In the presence of a polymer modification or blended additives, a misinterpretation may result because of interference from other components. Usually the amounts of additives used in a formulated product are relatively low, and their presence is seldom a major interference. An exception is experienced with certain plasticizers, in which the concentration is often high. A common example is plasticized poly(vinyl chloride), which is a mixture of poly(vinyl chloride), a stabilizer, and a plasticizer such as dioctyl phthalate (often diisooctyl isomer). In this example, features associated with the plasticizer dominate the infrared spectrum. Certain additives, such as fillers (calcium carbonate, for example) may also be misleading, and can confuse the spectral interpretation. For example, products fabricated from poly(vinyl chloride) are used for construction and piping, and these are typically formed from a blend of poly(vinyl chloride) and calcium carbonate. The two examples provided are the common cases where the additives dominate the infrared spectra, and these are sufficiently popular combinations that the spectra are easily recognized. 

Figure 57 NOESY spectra of a 40/60 blend of poly(vinyl chloride) and syndiotactic poly(methyl methacrylate) dissolved in tetrahydrofuran-dg at concentrations of (a) 22 wt% and (b) 38 wt%. (From Ref. 228, 1992 American Chemical Society.)... 

A direct comparison of the spatial resolution of XPS and transmission infrared spectroscopy imaging on heterogeneous polymer blends of poly(vinyl chloride)/PMMA was presented by Artyushkova et al. [226] The spatial resolution of the XPS and infrared instruments was 2-3 p,m and 7 p.m, respectively. The comparable resolution of the instrumentation allowed for images and spectra from the same areas of the samples to be directly compared (Fig. 32). 

Two-component systems have received some attention. - Poly(vinyl-idene fluoride>-poly(methyl or ethyl methacrylate)s blends have been mentioned in the previous section. A study of compatibility in blends of poly(vinyl chloride) and ethylene-vinyl acetate copolymer (EVA) has been reported. Spin-lattice relaxation time measurements were bi-exponential corresponding to rigid [poly(vinyl chloride)] and mobile (EVA) phases. A precipitated mixture showed intermingling of EVA in the poly(vinyl chloride) phase, but phase separation occurred on heating. Cashell et a/. have contributed a short note on the effects of magnetic susceptibility inhomogeneities of lincwidths in carbon black-filled... 

Poly(vinyl chloride) with a head-to-head structure has been prepared by chlorination of cu-polybuta-l, 4-diene and its thermal degradation was studied by a number of methods. The threshold temperature for breakdown was lower than that for normal poIy(vinyl chloride but higher temperatures were required to attain maximum rates. The same school has also studied decomposition of blends of poly(vinyl chloride) with various acrylates. The most important interactive effects occur when a small reactive entity produced by breakdown of one of the polymers diffuses into and reacts with the second. 

Hourston, D.J. and l.D. Hughes, Pol)nneric Systems For Acoustic Damping - 3. Blends Of Poly(Vinyl Chloride), Segmented PolyfEther Ester), And PolyfMethyl Acrylate). Journal of Applied Polymer Science, 26(10) p. 3487.1981. 

Crystallization of blended polymers leads to their phase separation, because the formation of isomorphic crystals occurs very rarely. Blends of poly(ethylene terephthalate) and poly(butylene terephthalate) remain miscible in the amorphous phase after crystallization of both components. Unlimited mutual solubility of polymers is exceptional. It can be achieved under certain conditions, for example, in blends of poly(vinyl chloride) and butadiene-nitrile rubber or poly(vinyl acetate) and cellulose nitrate. 

Lizymol, P.P., Thomas, S., and Jayabalan, M. (1997) Effect of dehydrochlorination of PVC on miscibility and phase separation of binary and ternary blends of poly(vinyl chloride), poly(ethylene-co-vinyl acetate) and poly (styrene-co-acrylonitrile). Polym. Int.,... 

Kok, M., Demirelli, K., and Aydogdu, Y. (2008) Thermophysical properties of blend of poly(vinyl chloride) with poly(isobomyl acrylate). Int. J. Sci. Technol., 3, 37-42. 

Garcia, D., Balart, R., Parres, F., and Lopez, J. (2007) Characterization of blends of poly(vinyl chloride) waste for building applications. J. Mater. Sci., 42, 10143-10151. 

De Oliveira W, Glasser WG (1994) Multiphase materials with lignin 7 Blends of poly(vinyl chloride) with lignin-caprolactone copolymers. J Appl Polym Sd 51 563-571 Toffey A, Glasser WG (1997) Cure characterization of polyurethanes with Ugnin and cellulose derivatives. Holzforschung 51 71-78... 

Binary blends of poly(vinyl chloride) (PVC) and poly(vinyl butyral) (PVB) prepared by solution casting showed a high degree of molecular mixing of these two polymers [a.l06]. The blends exhibited one major Tg whose position on the temperature scale is lowered with increasing level of PVB. The results showed the effect of dilution of PVC by the PVB molecules, which minimised the possible cross-dehydrochlorination reaction on the one hand, and the possible interference of some moieties of PVB with the PVC degradation products on the other. The thermal stability of the blends was found to increase with increase in the PVB content in the blend. The thermal degradation mechanisms of PVC/PVB (Scheme 9) were proposed too. 

Hourston D J and Hughes I D (1981) Polymeric systems for acoustic damping. III. Blends of poly(vinyl chloride), segmented poly(ether ester), and poly(methyl acrylate), J Appl Polym Sci 26 3487-3491. 

Xiao F, Shen D, Zhang X, Hu S and Xu M (1987) Studies on the morphology of blends of poly(vinyl chloride) and segmented polyurethanes, Polymer 28 2335-2345. Ahn T 0, Han K T, Jeong H M and Lee S W (1992) Miscibility of thermoplastic polyurethane elastomers with chlorine-containing polymers, Polymer 33 115-120. Flory P J (1953) Principles of Polymer Chemistry, Cornell University Press, Ithaca. Jeon H G, Mather P T and Haddad T S (2000) Shape memory and nanostructure in poly(norbornyl-poss) copolymers, Polym Int 49 453-457. 

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