ACRYLONITRILE GROUP

The separate phases will be rich in one component but may have the other present as a minor component. In order to control compatibility the elastomer may have reactive end groups to enhance interfacial adhesion. A common example in epoxy-resin technology is the carboxy-terminated butadiene-acrylonitrile copolymer (CTBN). The structure is shown in Scheme 1.47. In this resin the solubility in the epoxy resin is conferred by the acrylonitrile group, and an increase in the fraction present decreases the upper critical solution temperature, with 26% acrylonitrile conferring total miscibility of CTBN with a DGEBA-based epoxy resin (Pascault et al, 2002). 

The polyacrylamide flocculant can be produced by hydrolysis the polymer which contains acrylonitrile groups [4], The product of such reaction has much less molecular mass (approx. 5 104) and flocculating activity, than the product of AA polymerization. 

In experiments on immiscible blends, as noted by Dlubek et al. [2002], it is to be anticipated that the PALS parameters h and T3 will depend on the volume fractions and compositions of the three phases, as well as the effect of any interaction between the blend components. Such interactions have been identified in the studies of Wastlund et al. [1998] and Dlubek et al. [1999]. Thus, as pointed out above, the decrease in T3 observed by Wastlund et al. [1998] in 50 50 SMA24/SANx blends when the acrylonitrile content of the SANx increases from x=22% to x=33%, is interpreted as being due to increased interaction between the maleic anhydride and acrylonitrile groups. On the other hand, Dlubek et al. [1999] studied blends of an acrylonitrile-butadiene-styrene (ABS) copolymer and polyamide-6 (PA-6). This blend may be assumed to be quite heterogeneous, consisting of a two-phase structure having PA-6 crystals embedded in an amorphous ABS matrix and elastomeric... 

The yields are high when the reactions are carried out on dilute solutions of polyacrylonitrile in dimethylformamide at 75 °C. The solutions must contain 1.5 moles each of hydroxylamine hydrochloride and sodium carbonate per mole of acrylonitrile groups. ... 

For DSM and EPDM-60(I) the region of interfacial interaction is bounded by nonpolar BNR imits. The compatibility of chain portions of these EPDM samples with the polar acrylonitrile groups is ruled out. As the proportion of propylene xmits in EPDM is increased, the compatibility of the components, the density of the interfacial layer, and the amount of crosslinks in it drop sharply (the absolute value of-a " " increases). Thus,... 

The presence of the polar carboxyl groups also adds to the inherent oil and solvent resistance imparted by the acrylonitrile groups and the overall swelling resistance to fluids is improved. ... 

Galdamez et al. [67] have determined polymer-solvent interactions, as well as partition and diffusion coefficients for various solutes in poly(styrene-co-acryloni-trile). For this, they used the results of thermodynamic investigations to determine the degree of compatibility between poly(styrene-co-acrylontrile), and found aromatic solvents to be the most suitable for the examined copolymer. The values of partition coefficients depended slightly on the presence of acrylonitrile groups, but the diffusion coefficients of the migrating species were decreased systematically. 

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