Epoxy curing agents oligomers

The values (p j and can be determined according to the Eqs. (4.66) and (2.16), respectively. The theoretical dependence of (where - 1) on the ratio curing agent - oligomer AT, obtained by the indicated mode, is adduced in Fig. 7.9 (the shaded line). Its comparison with the experimental data shows the Eq. (7.15) inadequacy for epoxy polymers considered series (. estimation. Since the same equation describes well the data for a linear pol5uners number [51], then the comparison of the data of Fig. 7.9 and the results of Ref [51] assumes adequate usage of this method in the case of pol5uner molecular characteristics invariability only. 

Figure 5.2 The dependences of integral (1) and amplitude (2) X-ray scattering intensities on curing agent oligomer ratio for epoxy polymer EP-1 [3]...

In Figure 5.11 the dependence of on the ratio curing agent oligomer is adduced for epoxy polymers EP-1 and EP-2. The data of Figure 5.11 demonstrate that the dependence d KJ is a maximum at = 1.0, corresponding to the maximum in similar dependences and [28]. Hence, both the value of d and the cross-sectional area of the macromolecule, simulated by a cylinder, are also extremely changed. 

Figure 5.11 The dependence of Bragg s interval on the ratio curing agent oligomer for epoxy polymers EP-1 (1) and EP-2 (2) [31]...

Figure 9.31 The dependences of the microhardness of epoxy polymers (1, 2) and the loosely packed matrix (3, 4) on the curing agent oligomer ratio value K, for EP-2 (1, 3) and EP-2-200 (2, 4) [60]...

Uncured resins are oligomers of relatively low molecular weight that may be a liquid or a solid. Before epoxy resins can become useful products, they must be cured, with the addition of a curing agent. Curing involves the cross-linkage by polymerization of the reactive epoxy groups into a three-dimensional matrix. 

Siloxane-modified networks were prepared for testing via two steps. A linear precursor was generated by reacting the epoxy resin with the siloxane oligomer for one hour under vacuum at 65 °C. PACM-20 was then added, and the mixture was stirred for five minutes under vacuum at 50 °C. Previous studies indicated 151 that reaction between the AEP-terminated siloxane oligomers and the curing agent is not possible, as one would expect. 

Houston, TX), EPON Resin 828 is an epoxy oligomer made from bisphenol A and epichlorohydrin, while EPIKURE 3046 curing agent is an amidoamine mixture [1],... 

Figure 11.7 Fractal dimension (D) of a macromolecule section between chemical crosslinking points versus crosslinking density vf) for epoxy polymers based on epoxy oligomers and amino-containing curing agents. The D values were found from Equation (11.31) for a=A (1), A (2) and 0.25 nm (3).

For the study of the interphase tension at the boundary between the oligomer and a metal, a model system was used in which liquid mercury was used for the metal. The mercury was thoroughly purified and distilled prior to use. The interphase tension was determined hy the sessile drop method [230]. The error was estimated as 3mN/m. The oligomers and adhesives based on them were ED-20 epoxy resin-hased adhesive with PEP A curing agent (12%) and PN 609-2IM polyester resin-based adhesive with MEKP(O). 

Comparison of the concentration dependence of the Kic values of the compounds obtained by the above two methods with the concentration dependence of the X2,z thermodynamic interaction parameter of oligomer mixtures (epoxy resin-modifier and curing agent—modifier) displays the same dependences. The maximum value of of l.lMPa m / is observed at 5% content of the SKD-KTRA rubber. This is the region of maximal thermodynamic instabihty of the oligomer mixture. 

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