2DPP+HCE/DDM curing

As it follows from the adduced in Fig. 16 plots, the dependences [In (100-Q)] (t) proved to be linear, i.e., corresponding to the Eq. (86) of Chapter 1. This means that the system 2DPP + HCE/DDM curing reaction at all used T can be considered as classical reaction of the first order, proceeding in medium with small density fluctuations [17], The plots linearity allows to determine the coefficient A value in the Eq. (86) of Chapter 1 from their slope. It is easy to see from the data of Fig. 16 that T inerease results to A growth. Therefore in Fig. 17, the dependence of Aj 2 on T for the studied system is adduced which is approximated well enough by linear correlation and it can be expressed analytically as follows [34] ... 

The temperature T = 253 K in the Eq. (9) corresponds to the condition A = 0 (see Fig. 17) and this means that at all T < T the system 2DPP+HCE/DDM curing reaction does not occur. The comparison of coefficient A values, determined from linear plots of Fig. 16 A and calculated according to the Eq. (9) Aj, was adduced in Table 1, from which their satisfactory correspondence follows. 

Let us consider further the Eq. (27) of Chapter 1 application for the system 2DPP+HCE/DDM curing kinetics description. In Fig. 18 the dependences 0, in double logarithmic coordinates corresponding to the Eq. (27) of Chapter 1, were adduced. As one can see, they ate linear, that allows to determine from their slope the value of fractal dimension of microgels, forming in curing process. As the... 

Thus, the stated above results have demonstrated that both scaling Eq. (86) of Chapter 1 and fractal Eq. (27) of Chapter 1 (or Eq. (61) of Chapter 2) describe well to an equal extent haloid-containing epoxy polymer 2DPP+HCE/DDM curing reaction kinetics at different curing temperatures. In virtue of this circumstance there exists intercoimection between parameters included into the indicated equations. The fractal Eq. (61) of Chapter 2 introduces in the kinetics problem consideration reaction products structure (in the given case structure of microgels and condensed state after gel formation point), characterized by its fractal dimension D, that makes this conception physically more informative [34]. 

TABLE 4 The main dimensions of the system 2DPP+HCE/DDM curing process. 

The quoted above values p = 0.099-0.988 suppose that at the system 2DPP+HCE/DDM curing only slow diffusion (subdifhisive transport) is realized and reaching at T 513 K the condition = d = d means that in this case classi-... 

Table 10.1 The dependence of time of achievement of the first gelation point from curing temperature T for system 2DPP+HCE/DDM ...

Two main distinctions of curves for the indicated systems attract our attention. Firstly, for system 2DPP+HCE DM the smooth decrease of a slope of curves is observed in the process of increase t, whereas for system EPS-4/ DDM the linear dependence up to the large (about 0.8) values Q is observed. Secondly, if the limiting conversion degree of curing reaction for the system 2DPP+HCE/DDM is the function of T (the more T the more this degree), then for the system EPS-4/DDM such dependence is not present and at all used T maximum value Q is observed, close to one. 

FIGURE 11 The dependence of microgels fractal dimension on curing reaction duration t for the system EPS-4/DDM. The condition D(.= const for the system 2DPP + HCE/DDM was shown by a shaded line. 

As it was noted above, for analysis of polymerization reactions in general and cross-linked polymers curing reactions in particular a number of physical conceptions can be used, from which two of them will be considered below. The indicated conceptions were used as basic relationships of the Eq. (26) and (86) of Chapter 1. In Fig. 16, the dependences of In (100-Q) on t in lo rithmic coordinates, corresponding to the Eq. (86) of Chapter 1, are adduced for the system 2DPP + HCE/DDM at six T values, where Q is given in percentage. 

FIGURE 17 The dependence of parameter on curing temperature for system 2DPP+HCE/DDM. 

Euclidean (up to gelation point) to fractal (after it) reduces sharply curing rate of system 2DPP+HCE/DDM. The fact that after the gelation point the plots slope in Fig. 23 is independent on Tcur, indicates unequivocally on spatial (due to diffusion conditions reagents) disorder nature, defining replacement ds on d. ... 

FIGURE 26 The dependence of conversion limiting degree of curing reaction on exponent for the system 2DPP+HCE/DDM. 

Figure 3.9 The experimental (1,2) and theoretical (3-5) kinetic curves a t) for systems 2DPP+HCE/DDM (1, 3) and EPS-4/DDM (2, 4, 5). Curve 5 corresponds to the curing reaction of system EPS-4/DDM in Euclidean space [38]...

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