Glass transition, interval experimental

Fig. 6. The hole formation energy 2ajk), the barrier to internal rotation (/de/fi) and the glass transition temperature vs. compoafdon for NaPOjijCa(PO, counterion copolymers (2 /ft) and (Aelk) calculated from the Gibbs-DiMarzio theory at 10% intervals. T, points experimental...

The experimental evidence led to the conclusion that the onset of the glass transition is accompanied by phase transformation in the stmcture of the as-spun CPE-1 fibers. This phase transformation is accomplished at 250° C. Only at this temperature the development of crystalline phases in CPE-1 becomes well pronounced (Figure 8d). What is the origin of this transition at 180-250°C, which is concurrent with the glass transition of copolyester (the temperature interval of the glass transition as detervined by DMR and DSC scans from 110 to 230°C) Let us analyze the experimental evidence obtained in terms of the hypothesis of a single-phase smectic LC stmcture in the as-spun CPE-1 fibers. 

Interval III Particle Growth in the Absence of Monomer Droplets.—James and Sundberg have published the results of an experimental study of ideal and non-ideal behaviour in the seeded emulsion polymerization of styrene. Unlike the experiments on seeded emulsion polymerization reported in papers referred to above, the amounts of monomer added to the seed latices were less than those required to saturate the particles and form a separate monomer droplet phase. The reaction systems were therefore the seed analogues of Interval III of a conventional emulsion polymerization reaction. The results are found to be in good agreement with the predictions of the Stockmayer-O Toole theory, provided that allowance is made for the effect of monomer/polymer ratio at the reaction locus upon the rate coefficient for bimolecular mutual termination. A paper by Hamielec and Marten is concerned with the effects of chain entanglements and the rubber-glass transition... 

Some experimental data show that the dimensions of the particles of the dispersed phase affect the position of the glass transition temperature, the broadness of the transition interval, and even determine the very possibihty of detecting the glass transition of this phase experimentally [241,242]. 

Figure 2. Experimental heat capacities of PET. The glass-transition region is marked by Tg, the melting region by Tm-The solid, thin lines indicate the data of Table 37, the dashed line indicates the crystallinity-corrected heat capacity for the semi-crystalline sample, 44% crystalline, 56% amorphous. The quasl-isothermal data were measured by TMDSC at 2 K intervals with a sinusoidal temperature modulation of d 1, 0 K and a modulation period of 60s (Ref. 35).

Validation of the Si02 DPD Fluid Model against Experimental Data A series of model runs were carried out to fit the DPD calculated silica viscosity against experimental data. The viscosities of silica from 800 K to 2200 K were calculated using the Poiseuille flow method at 200 K intervals. An additional simulation was carried out at the glass transition temperature of 1500 K. The force applied to the fluid was 0.015 DPD units. The dissipative force constant was set to be = 36.0. 

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