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TGA Isothermal

Polymers have inherently high hydrocarbon ratios, making liquefaction of waste plastics into liquid fuel feedstocks a potentially viable commercial process. The objective is to characterise the thermal degradation of polymers during hydrogenation. LDPE is studied due to its simple strueture. Isothermal and non-isothermal TGA were used to obtain degradation kinetics. Systems of homopolymer, polymer mixtures, and solvent-swollen polymer are studied. The significant variables for... [Pg.74]

Cellulose pyrolysis kinetics, as measured by isothermal TGA mass loss, were statistically best fit using 1st- or 2nd-order for the untreated (control) samples and 2nd-order for the cellulose samples treated with three additives. Activation parameters obtained from the TGA data of the untreated samples suggest that the reaction mechanism proceeded through an ordered transition state. Sample crystallinity affected the rate constants, activation parameters, and char yields of the untreated cellulose samples. Various additives had different effects on the mass loss. For example, phosphoric acid and aluminum chloride probably increased the rate of dehydration, while boric acid may have inhibited levoglucosan... [Pg.358]

Figure 6. Isothermal TGA trace at 300°C for post-cured 3/1 blend of 4-allyloxystyrene/divinyl ether blend. Figure 6. Isothermal TGA trace at 300°C for post-cured 3/1 blend of 4-allyloxystyrene/divinyl ether blend.
Semiconductor Grade Epoxies. As was the case for the semiconductor grade silicone-epoxy, there was no difference between FR and non-FR epoxies recorded by either DSC or EGA below 200°C. However, the nominally equivalent non-FR epoxy exhibited significantly lower thermal stability as indicated by the Isothermal TGA data. Furthermore, the aqueous extract of the non-FR compound contained more than twice as much Cl as the combined concentrations of Cl and Br in the FR epoxy. Although there have been no direct comparisons on device aging with these two epoxies, the above findings indicate that the FR compound, being cleaner and more thermally stable, could actually be the better material for encapsulation applications. [Pg.231]

The order of thermal stability based upon the results of the isothermal TGAs was concluded to be 70 > 71 > 68 > 72. This same order was proposed to reflect the relative reactivity of the monomers in a Diels-Alder reaction. [Pg.48]

Vahlas and coworkers recently tested a new delivery system based on sublimation in a fluidized bed, to improve mass and heat transport. A mixture of solid Al(acac)3 (minor component) and inert alumina or silica particles was fluidized with a combination of water vapor and oxygen at 150 °C, by which amorphons AI2O3 films were obtained on Ti6242 alloy wafers immersed in the bed. Pauleau and Dnlac compared the kinetics of vaporization of Al(acac)3, Al(tfac)3 and Al(hfac)3 by isothermal TGA. The satnration vapor pressure of Al(hfac)3 is 10-fold and 100-fold higher than those of Al(tfac)3 and Al(acac)3, respectively. [Pg.970]

In isothermal TGA, the specimen is kept at a constant elevated temperature, and its weight is measured at regular intervals, to provide data on the weight loss as a function of time at the temperature of measurement. [Pg.614]

Dynamic TGA provides a better indication of short-term TTOS. Isothermal TGA provides a better indication of long-term TTOS. Dynamic TGA is much less time-consuming, and thus more routinely performed, than isothermal TGA. It was once believed that isothermal TGA results could be correlated in a simple manner with dynamic TGA results, so that isothermal... [Pg.614]

TGA behavior could be predicted from dynamic TGA behavior. Such extrapolations have, however, been found to have only very crude qualitative validity, and to fail at a quantitative level. It is possible for two polymers to have similar weight retention curves in dynamic TGA scans, but for one of them to lose weight considerably more rapidly in isothermal TGA [4,5]. [Pg.615]

G. Allen et al. (10) studied the thermal degradation of several poly(aryloxy- and fluoroalkoxyphosphazenes) by use of isothermal TGA and retention of solution viscosity. Thermal stability was determined by the temperature at which the samples exhibited 10% weight loss. No mechanism was presented for the thermal degradation. [Pg.300]

Isothermal TGA mass/temperature curves of a PP powder sample (non-stabilised)... [Pg.65]

Table 2.1 Results of isothermal TGA experiments on non-stabilised PP powder samples... Table 2.1 Results of isothermal TGA experiments on non-stabilised PP powder samples...
The mass/time curves of a non-stabilised and a stabilised PP sample during isothermal TGA experiments at 250°C (nitrogen atm.)... [Pg.70]

Non-isothermal TGA mass/temperature curves of DIBP, MgC12 and a mixture of MgC12/DIBP measured in a nitrogen atmosphere... [Pg.73]

Mass increase of a syndiotactic 1,2-polybutadiene (ex-JSR) sample during an isothermal TGA experiment at 240°C in air... [Pg.287]

Non-isothermal TGA experiments showed that sample B still contained 13.5 %wt. MIBK while sample C still contained 4 %wt. MIBK. The TGA experiments also showed that a temperature of about 250°C is necessary to remove the residual solvent from the samples B and C within a reasonable amount of time (l to 2 hour). [Pg.340]


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See also in sourсe #XX -- [ Pg.385 ]

See also in sourсe #XX -- [ Pg.208 ]

See also in sourсe #XX -- [ Pg.181 ]




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Isothermal TGA experiments

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