Polyvinyl chloride glass transition temperature

The most common backbone structure found in commercial polymers is the saturated carbon-carbon structure. Polymers with saturated carbon-carbon backbones, such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyacrylates, are produced using chain-growth polymerizations. The saturated carbon-carbon backbone of polyethylene with no side groups is a relatively flexible polymer chain. The glass transition temperature is low at -20°C for high-density polyethylene. Side groups on the carbon-carbon backbone influence thermal transitions, solubility, and other polymer properties. 

For many years, it has been known that a small quantity of plasticizer acts as an anti plasticizer for polyvinyl chloride (PVC). During a recent search for effective plasticizers for polycarbonate, W. J. Jackson and J. R. Caldwell found several groups of compounds which acted as antiplasticizers. They increased the tensile modulus and strength and reduced the elongation of polycarbonate films. In contrast to plasticizers, these antiplasticizers affected glass transition temperature quite differently. Their mechanism is explained by the fact that they either increase crystallinity or reduce the mobility of the polymer chain through the bulkiness of their molecules. 

Generally one thinks of polyvinyl chloride as a rigid plastic, which it is, with a glass transition temperature around 85°C. However, the addition of polar chemicals such as dioctyl phthalate can reduce the glass transition temperature below room temperature, producing a rubbery material. 

In this study, we discussed the graded and miscible blend of polyvinyl chloride(PVC)/ polymethacrylate(polymethyl methacrylate(PMMA) or polyhexyl methacrylate(PHMA)) by a dissolution-diffusion method, and characterized graded structures of the blends by measuring FTIR spectra and Raman microscopic spectra, and thermal behaviors around the glass transition temperature(Tg) by DSC method, or by SEM-EDX observation. Finally, we measured several types of mechanical properties and thermal shock resistance of the graded polymer blends. 

Polarity, for example, has an influence on chemical stability (chlorine atom in polyvinyl chloride). Bulky pendant groups (phenyl residue in polystyrene) for example, move the glass transition temperature up and produce brittle, stiff plastics. 

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.)... 

Estimate the glass-transition temperature of polyvinyl chloride, Tg, with repeating unit, —(CH2CHCI)—, using the following group contributions (van Krevelen, 1990) ... 

Glass transition temperature (Tg) The temperature where the polymer transits from a rubbery state to a glassy state. The thermal expansion coefficient in the rubbery state is two to three times greater than in the glassy state because of greater molecular (chain) mobility. Tg varies between —120 and +130°C, depending on the type of polymer. Rubbery polymers such as elastomers have —ve Tg, i.e. Tg is well below their use temperature, whereas common plastics such as polyvinyl chloride (PVC) polymers have + ve Tg, i.e. Tg is well above their use temperature. However, if used above its Tg, PVC would display the usual rubber-like behaviour. 

Which has the higher glass transition temperature, chlorinated polyvinyl chloride or polyvinyl chloride Why ... 

Chlorinated polyvinyl chloride has the higher glass transition temperature because the added chlorines restrict chain segment mobility when subjected to thermal energy. 

The melting behavior and thermal characteristics of PP contributing to the aforementioned problems have been extensively studied and reported upon. They are largely due to the semicrystalline nature of PP which results in a sharp melting point at around 165°C. Amorphous polymers, such as PS and polyvinyl chloride (PVC), gradually soften on heating above their glass transition temperatures. Conversely, PP melts very... 

One way to obtain long-term information is through the use of the time-temperature-superposition principle detailed in Chapter 7. Indeed, J. Lohr, (1965) (the California wine maker) while at the NASA Ames Research Center conducted constant strain rate tests from 0.003 to 300 min and from 15° C above the glass transition temperature to 100° C below the glass transition temperature to produce yield stress master curves for poly(methyl methacrylate), polystyrene, polyvinyl chloride, and polyethylene terephthalate. It should not be surprising that time or rate dependent yield (rupture) stress master curves can be developed as yield (rupture) is a single point on a correctly determined isochronous stress-strain curve. Whether linear or nonlinear, the stress is related to the strain through a modulus function at the yield point (mpture) location. As a result, a time dependent master curve for yield, rupture, or other failure parameters should be possible in the same way that a master curve of modulus is possible as demonstrated in Chapter 7 and 10. 

The majority of thermoformable thermoplastics is amorphous, meaning that at a specific temperature, called the glass transition temperature, the plastic changes from a brittle, glassy state to a ductile, rubbery state. PS, ABS, polyvinyl chloride (PVC), and polycarbonate are examples of thermoformable amorphous plastics. 

Though all three products exhibit the same glass transition temperature, the heat-seal temperature of the surfactant emulsion is below that of either the PVOH-protected or the cellulosic emulsions. Fig. 8 shows the difference between the PVOH-protected and the surfactant emulsion in laminating films of polyvinyl chloride to each other, using a heat-seal technique. In this case, each emulsion was coated onto a PVC film, allowed to dry, then heat sealed at the... 

First, studying different polar polymers [258,263-265] such as poly(ethylene oxide) (PEO), polyvinyUdene fluoride (PVdF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC) in order to enhance the ionic conductivity of the SPEs. PEO has been foimd to be the most successful host material for SPEs due to its low glass transition temperature (-60 °C) [266]. Second, increasing the niunber of charge carriers by use of highly dissociable salts, and increasing the salt concentration. Third, suppressing the crystallization of the polymer chains reduces the conductivity at room temperature ([Pg.1101]

Non-volatile esters are widely used as plasticizers for PVC. The relationship between PVC and ester solvents is similar to chloroform and acetone. They are used as plasticizers because they soften the PVC. Effectively they reduce the glass transition temperature of the amorphous regions below room temperature. The most famous of these ester-based plasticizers are phthalates (e.g., dioctyl phthalate). Table 3.6 lists various ester-based and other plasticizers for polyvinyl chloride. 

Woodward and Sauer (1958), have reviewed the many studies of polyvinyl chloride. The only correlation that can be seen between the mechanical and calorimetric data is related to the glass transition which occurs at 92, and 107° C as detected by mechanical damping peaks using 0.67 and 500 cps respectively. These temperatures are to be compared... 

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