Starting temperatures of decomposition

Table I. Starting temperatures of decomposition (T

Table II. Inherent viscosities (tjinh s), glass transition temperatures (Ta s) and starting temperatures of decomposition (T

Thermal properties of the polyesters obtained were studied by TG and DSC. The starting temperature of decomposition (Tfrom Table III, Tpolymer measured in air is lower than that measured in nitrogen. T[Pg.219]

Table III. Starting temperatures of decomposition (T s) of polyesters (XII) with syringyl-type biphenyl units...

The numerous studies ofthe thermolysis reactions of Al(OR)3 have been summarized in the review by Piekos [1301]. They permit a conclusion that the the starting temperatures of decomposition are not constant but depend on the rate of heating and the time of preliminary treatment. The general scheme of decomposition proposed by Tishchenko includes for the first step the formation of ethers and A10 (0R)3.n. Next comes the dehydration of ethers ... 

Density Tensile Strength, MPa Elongation at Break, % Melting PoinC C Starting Temperature of Decomposition," C... 

Table IV. Glass transition temperatures (T s) and starting temperatures of decomposition (T i s) of poly ethers XIV-A and -B...

Both zirconium hydride and zirconium metal powders compact to fairly high densities at conventional pressures. During sintering the zirconium hydride decomposes and at the temperature of decomposition, zirconium particles start to bond. Sintered zirconium is ductile and can be worked without difficulty. Pure zirconium is seldom used in reactor engineering, but the powder is used in conjunction with uranium powder to form uranium—zirconium aUoys by soHd-state diffusion. These aUoys are important in reactor design because they change less under irradiation and are more resistant to corrosion. 

Instrumental factors. Heating rate. When a substance is heated at a fast rate, the temperature of decomposition will be higher than that obtained at a slower rate of heating. The effect is shown for a single-step reaction in Fig. 11.4. The curve AB represents the decomposition curve at a slow heating rate, whereas the curve CD is that due to the faster heating rate. If TA and Tc are the decomposition temperatures at the start of the reaction and the final temperatures on completion of the decomposition are TB and TD, the following features can be noted ... 

TGA analysis shows that polymer degradation starts at about 235°C which corresponds to the temperature of decomposition of the cellobiose monomer (m.p. 239°C with decom.). Torsion Braid analysis and differential scanning calorimetry measurements show that this polymer is very rigid and does not exhibit any transition in the range of -100 to +250 C, e.g. the polymer decomposition occurs below any transition temperature. This result is expected since both of the monomers, cellobiose and MDI, have rigid molecules and because cellobiose units of the polymer form intermolecular hydrogen bondings. Cellobiose polyurethanes based on aliphatic diisocyanates, e.g. HMDI, are expected to be more flexible. 

The Lewis and Bronsted acids lower the starting temperature of wood decomposition and charcoal formation and along with an increased char formation, diminish the yield of some volatile products of pyrolysis. The latter fact is an undesirable i enomenon if an energetic self-sufficiency in the carbonisation of wood is striven for (10), Therefore, the objective of the present investigation was to elucidate not only the effect of different available catalysts upon the yield of charcoal, but also that on the yield of volatile products. 

The sample of nano-TiO -S is characterized by high thermal stability in the 20-900°C temperature interval, where the total mass loss is 5% (Fig. 7, curve 7 Fig. 8, a, curve 1), while the total mass loss for the PAn sample is reached to 95% (Fig. 7, curve 7 Fig. 8, b, curve 1). Therefore, the main mass loss in the composites is eormected with the thermal decomposition of polymeric component and values of total mass loss increases with inereasing of PAn content in the samples (Fig. 8, curves 2-6). In the same time, the increasing of TiO -S nanopartieles in the samples leads to the deereasing of thermodestruction rate of polyaniline component. It indicates the lower grade of TG curves in the 230-600°C temperature s interval. Besides, temperature of the termination of Pan component thermal destruetion in the composites samples is shifted in the side of lower temperatures, whereas the start temperature of eomposites... 

Figure 5.2 shows the thermogravimetric (TG) curves of the sample irradiated up to 10 kGy (the same sample as used in Fig. 5.1). The weight loss due to the thermal decomposition seems to occur in two stages the first stage in the TG curves is observed at about 200 C, the second at about 300 °C. Irradiation reduces the decomposition during the first stage and shifts the starting temperature of the decomposition to the lower temperature side.

Figure 1.1 compares the flame retardant efficiency of aliphatic brominated flame retardant and aromatic brominated flame retardant. Because the thermal decomposition of the aliphatic flame retardant starts at temperatures below the thermal decomposition of pol5T)ropylene, it shows very good performance in polypropylene. In contrast, because the aromatic brominated fire retardant is significantly more stable, optimum debromination is not achieved at the temperature of decomposition of polypropylene, and this flame retardant shows inferior performance. 

The chromates(V) are stable to above 600°C, where decomposition with loss of oxygen takes place and chromites(III) are formed. According to Doyle and coworkers the starting temperature of the decomposition reaction, as measured from the TG and DTA curves, is almost invariant in the series Sm - Yb, where the values range from 660 to 692°C. Only praseodymium seems to have lower... 

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