PEMA homopolymer

Figure 10 Separation of a homopolymer mixture of poly (ethyl methacrylate) (PEMA), polystyrene (PSTY) and poly (lauryl methacrylate) (PLMA) by Orthogonal Chromatography at different % n-heptane concentrations in SBC 2.

The homopolymers poly(methyl methacrylate) and poly-(ethyl methacrylate) are compatible with poly(vinylidene fluoride) when blended in the melt. True molecular com-patibility is indicated by their transparency and a single, intermediate glass transition temperature for the blends. The Tg results indicate plasticization of the glassy methacrylate polymers by amorphous poly(vinylidene fluoride). The Tg of PVdF is consistent with the variation of Tg with composition in both the PMMA-PVdF and PEMA-PVdF blends when Tg is plotted vs. volume fraction of each component. PEMA/PVdF blends are stable, amorphous systems up to at least 1 PVdF/I PEMA on a weight basis. PMMA/ blends are subject to crystallization of the PVdF component with more than 0.5 PVdF/1 PMMA by weight. This is an unexpected result. 

The reader should note that PEMA homopolymer yields the highest values for E" vs temperature. Figure 4, but the lowest values for tan vs temperature. Figure 5. This peculiar feature of damping curves will be discussed further below. 

Figure 4. Values of lossy modulus, E". Data from references 1, 5, and 8. The data for PEMA was obtained from 3G" at 1 Hz and converted to 110 Hz. The PEMA homopolymer is seen to have a very high E" value over a broad temperature range brought about by the strong secondary transition. With no common comonomer the loss peaks and also tan S peaks (Figure 5) of the IPN s tend to be bimodal.

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... 

Styrene (2-5vol% in CH2C12) was polymerized with HC104 (0.01 mole l-1) and the system was kept at —78 °C a few minutes. Then, the second monomer 1 -/-butyl aziridine (TBA) or l(2-phenylethyl)-2-methyl aziridine (PEMA) was added to the solution 104). The mixture was stored at —78 °C for several hours and then warmed up to room temperature. A sample of polystyrene solution was taken before the addition of aziridine and its Mn was determined. A block copolymer was isolated and its Mn was determined separately. GPC traces of both products showed unimodal molecular weight distributions. The GPC trace of the copolymer indicated a considerable molecular weight increase, as compared to the homopolymer. Two block copolymers were obtained with Mn = 4,100 (starting from polystyrene of Mn = 800) and Mn = 7,100 (from polystyrene of Mn = 1,800). 

A couple of years later [167], they studied the oxidative polymerization of PEMA with FeCla in nitromethane and obtained conductivities of approximately 5xl0" Scm" after doping with iodine. The homopolymers were well characterized using proton NMR, IR, GPC and TGA. Next, they [168]... 

---