PEMA/PnBA,

PEMA-PnBA semi-l-IPN synthesised in water (0%) and in an ethanol water mixture (10%). 

Log E versus temperature plots (10 Hz) for the PEMA-PnBA semi-l-IPN system in which the PEMA contains zero (1), three (2) and five (3) mole percent of crosslinker. 

Some two stage emulsion graft copolymer materials synthesized and characterized by DMS include) the series poly (methyl methacrylate)/poly(n-butyl acrylate) (PMMA/ PnBA) synthesized by Dickie (14) and the series poly(ethyl methacrylate)/poly(n-butyl acrylate) (PEMA/PnBA) synthesized by Sperling et al. (1) The present study will continue the development of the PEMA/PnBA damping materials by incorporating a common comonomer) ethyl acrylate (EA)) in both stages of the emulsion polymerization. 

We are now in a position to model the temperature dependence of E". For a completely compatible system, exemplified by the "Millar" IPN, the sharp homopolymer transition behavior is observed. Figure 10a. With the addition of significant non-identical comonomers to polymers I and II, the transition is broadened, but a single peak is maintained. Figure 10b. The semi-compatible PEMA/PnBA system, containing no ethyl acrylate, displays two peaks (see Figures 4 and 5), as modeled in Figure 10c. A completely incompatible... 

The equations, fit to the data by stepwise linear regression, ( 2) are shown in Table V, In addition to the ten samples of the current study listed in Table I, homopolypolymer data and data for the three latex PEMA/PnBA IPN s, shown in Figures 4 and 5, were also included in the generation of the equations. 

A similar experiment has been performed via another route. Here a semi-1-IPN based on PEMA and PnBA was synthesised by both use of a thermal initiator (ammonium persulphate) at 90 C and via a redox initiator (ammonium persulphate-sodium metabisulphate) at 20 C, which is well below the Tg of PEMA. The data are shown in Figure 9. 

Figure 8.29. DMS of poly(n-butyl acrylate)/poly-(ethyl methacrylate), PnBA/PEMA, latex 50/50 IPN and inverse composition. Dynamic mechanical spectroscopy at 110 Hz shows the two structures to be different. (A, A) 50 PnBA/50 PEMA (O, ) 50 PEMA/50 PnBA. (Sperling et al, 1972.)...

The tacticity of PMMA blends with poly(vinyl pyrrolidone)(PVP) influenced the blend phase behavior as atatic and syndiotactic PMMA were miscible with PVP, but isotactic PMMA was phase separated [785]. Neo and Goh [786], however, reported that PVP was immiscible with PMMA and PEMA, but miscible with poly(chloromethyl methacrylate) and poly(2-chloroethyl methacrylate. Miscibility with ucst behavior was observed for poly(n-butyl acrylate) PnBA blends with poly(propylene glycol) (linear and three arm star) oligomers [787]. Poly(vinyl butyral)/PMMA blends were found to be phase separated at high PMMA [788]. 

---