Glass transition temperature of PVC

The glass transition temperature of PVC is lowered by di(ethylhexyl)phthalate. 

Figure 2.24. Glass transition temperature of PVC containing different concentrations of plasticizer. [A - Woo, L. Westphal, S. R Shang, S. Ling, M. T. K., Thermochim. Acta, 284, 57-66,1996 B - Beimes, K. I Bums,...

Figure 3.6. Glass transition temperature of PVC containing variable quantities of plasticizer. [Data from Dashora, P. Gupta, G, Polymer, 37, 2,231-4,1996.]...

Nakajima apphed SALS to plasticizers of different compatibility with PVC. For more compatible plasticizers the size of the PVC particles increases faster and at lower temperatures than in the case of less compatible plasticizers. The beginning of swelling takes place around the glass transition temperature of PVC. At this temperature, the PVC chains have enough mobility to allow plasticizer penetratiom Hwee-Khim and Shaw employed this techniqne to estabhsh the compatibility of a series of plasticizers in PVC gels (concentrations aronnd 1-15%). Under these conditions, the authors found a clear relation between the gelation temperature and the plasticizer concentration. 

Figure 10.55. Effect of tricresyl phosphate concentration on glass transition temperature of PVC. [Data from Borek J Osoba W, J. Polyni. Sci. Polym. Phys. Ed., 36, No.ll, Aug.1998, p.1839-45.]...

Figure 11.47. Glass transition temperature of PVC-di-(2-ethylhexyl) phthalate vs. weight fraction of PVC. [Data from Vilics T Schneider H A Manoviciu V Manoviciu I, Polymer, 38, No. 8, 1997, p. 1865-70.]...

Figure 12.2. Glass transition temperature of PVC-DOP compositions measured in the blend of PVC and DOP and in the ternary blends containing CPE, PVC, and DOP. [Data from Champagne M F Prud homme R E,...

Figure 15.3. Glass transition temperature of PVC plasticized with different concentrations of diisodecyl phthalate. [Data from Turi E A, Thermal Characterization Polymeric Materials. Volume 2. Second edition, London, 1991, Academic Press Ltd.]...

The glass transition temperature of PVC varies with the polymerization method, but falls within the range of 60 to 80°C. PVC is a selfextinguishing polymer and, therefore, has apphcation in the field of wire and cable. PVC s good flame resistance results from removal of HCl from the chain, releasing HCl gas. Air is restricted from reaching the flame because HCl gas is denser than air. Because PVC is... 

Solvent evaporation This method is the most popular. The electro-active material of the membrane and PVC are dissolved in a proper amount of tetrahydrofuran (THE), a low-boiling solvent, (approx. 40"C), and then, after evaporation of the solvent, the resulting membranes of approx. 0.5 mm in thickness, are placed at the tip of a PVC tube [20]. Plasticization occurs at a lower temperature than the glass transition temperature of PVC. 

Samples C8 and D13 differ in Tg in fact, the Tg (extrapolated) of C8 is about 10°C higher than that of D13. For the blends, a clearly defined maximum of the logarithmic decrement A is observed at about 85°C—i.e.y at the glass transition temperature of the homopolymer PVC. This indicates incompatibility between PVC and CPVC (II). The in-... 

Increases in number average molecular weight, Mn, and cross-link density will both act to increase the T. The addition of plasticizers, such as in the case of PVC, will decrease the value of the glass transition temperature. The glass transition temperature of the plasticized... 

Kanemitsu and Einami (1990) investigated the role of the polymer on hole transport in a series of 2-(p-dipropylaminophenyl)-4-(p-dimethylaminophenyl)-5-(o-chlorophenyl)-l,3-oxazole (OX) doped polymers. The polymers were a polyarylate (PA), bisphenol-A polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene) PS, poly(vinyl chloride) (PVC), polyethylene terephthalate) (PET), and poly(vinyl butyral) (PVB). The glass transition temperatures of the polymers range from 322 (PVB) to 448 K (PA). The temporal features of the photocurrent transients were strongly dependent on the polymer. Figure 76 shows the results. The field was 4.0 x H)5 V/cm and the temperature 295 K. The transients were near rectangular for PS, PET, PA, and PMMA, and highly dispersive for PVC land PVB. This was attributed to the fact... 

Figure 19. Effect of hydrostatic pressure on the glass transition temperature of unplasticized and DOP-plasticized PVC.

PVC melts have a dry appearance, little strength, and lack of adhesion to a metal surface. Process aids are designed to change all these properties. Almost all rigid formulations and many flexible ones use acrylic process aids. Acrylic process aids are copolymers of methylmethacrylate with ethyl acrylate, butyl acrylate, or butyl methacrylate.Selection of monomers is important because it affects the glass transition temperature of copolymer, which should be lower than that of PVC to cause additive to melt below PVC process temperature and thus help to process it. 

Glass transition temperature of the components in polymethyl methacrylate/polystyrene (PMMA/PS) ( , PMMA O, PS) and polyvinyl chloride (PVC)/PS (A, PVC PS) blends. (Reproduced from Fekete, E., Foldes, E., and Pukanszky, B. 2005. Effect of molecular interactions on the miscibility and structure of polymer blends. European Polymer Journal 41 727-736 with permission from Elsevier.)... 

Figure 10.34. Various kinds of concentration dependencies of the glass transition temperature for polymer-plasticizer systems. 1 - PVC-ethyl stearate, 2 - PVC-dibutyl phthalate, 3 - butadiene rubber SCD-trans-former oil, ° 4 - line connecting the points corresponding to the glass transition temperature of transformer oil and the point corresponding to the system 3 with the largest fraction of plasticizer.

Two processes may potentially take place in the presence of plasticizers increased mobility may induce crystallization or the solvating power of the plasticizer may affect crystalline phase or interfere with crystallization. Before these two potential results are discussed the effect of the plasticizer on chain mobility is reviewed. Figure 10.55 shows that the glass transition temperature of plasticized PVC is a linear function of plasticizer concentration. Figure 10.56 shows that introduction of the plasticizer increases a free volume. Figure 10.57 shows that the free volume linearly increases in plasticized polyethylene oxide. " These three graphs are characteristic of the main functions of plasticizers which are to make polymers more elastic and increase their tolerance to lowering the temperature. In fact, addition of the plasticizer and temperature increase have a very similar effect on the resultant flexibility and mobility of chain (plasticization and plastification, respectively). 

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