Blending in Solution

In yet another example showing how simple solution blending of CP composites can be, Ogura et al. [360] prepared composite films of poly(o-phenylene diamine) (P(oPD)) and PVA simply by casting from solutions of the two polymers in DMSO (dimethyl sulfoxide). They claimed percolation thresholds of 0.1 v/v% (sic) for saturation conductivities of ca. 0.1 S/cm, which however have not been duplicated anywhere else. These dark composites were used as humidity sensors. 

Hotta et al. [130] used chloroform solutions of a copolymer of 3-hexyl and 3-benzyl thiophenes and polystyrene (PStyr) to deposit films on glass slides. When solution doped with NOPFg in acetonitrile, they yielded conductive composites with a ca. 20 v/v% percolation threshold for a 1 S/cm saturation conductivity. Films cast on ITO/glass showed an acceptable electrochromic effect. 

Pron et al. [246] used novel phosphoric acid diesters to protonate the emeraldine base form of P(ANi) in solvents such as toluene, decaline or m-cresol, yielding solutions of the conductive form of the CP. Solutions of the highly versatile thermoplastic Acrylonitrile-Butadiene-Styrene (ABS) were then mixed with these 

Gongalves et al. [362] used a simple solution casting method to fabricate free standing polyurethane/poly(o-MeO-aniline) composite films from a solution in DMF. The percolation threshold was 10 w/w%, and loadings of 65% CP gave conductivities of 10 S/cm. X-Ray studies indicated significant crystalline sections in the composite. 

A low percolation threshold, ca. 3 w/w% for a conductivity of ca. 10 S/cm, was claimed by Banerjee and Mandal [363] for P(ANi)/PVC films prepared using a unique method. This method used sub-n-particulate P(ANi)Cl, stabilized with ca. 5 % poly(vinyl methyl ether), and a THF solution of PVC. The P(ANi) particles were dispersed in the PVC solution using ultrasound, and films were cast therefrom. TEM images at the percolation threshold indicated dispersed P(ANi) particles achieving intercoimection. 

---

A mixture of a BMI (Compimide 796) with 4,4 -bis(orf/zo-propenylphe-noxy)benzophenone (TM 23) was blended in solution with Udel 700 (polysul-fone from Union Carbide), Ultem 100 (General Electric polyether imide), and PH 10 (Bayer polyhydantoin) (Fig. 35). The thermoplastics were introduced at various concentrations up to 33%. A phase segregation did not appear with PH 10, but two phases were observed with Ultem. With both semi-IPNs the observed Glc were found to be four- to fivefold the Glc of the neat BMI [113]. 

In the above, we have seen that a certain interpolymer interaction is required for different polymers to be miscible. Here, we will see that high resolution NMR enables us to locate interacting regions in component polymers. One of the most useful methods is the nuclear Overhauser effect (NOE) between H— H and H—NOE can be observed between spins whose distances are less than about 0.5 nm. The one- (ID) and two-dimensional (2D) NOE experiments have been used to reveal the spatial structure of biomolecules in solutions. Of course, these can be applied to locate interacting regions in a blend in solution and in solids [3]. For example, Crowther et al. [22] and Mirau et al. [23] applied NOE experiments to polystyrene/poly(vinyl methyl ether) (PS/PVME) in a toluene solution, and show that the interpolymer NOE signals between the aromatic protons of PS and the methoxy protons of PVME can be observed at polymer concentrations higher than 25 wt%. In the solid state, Heffner and Mirau [24] measured 2D H— H NOESY (NOESY nuclear Overhauser effect spectroscopy) spectra of 1,2-polybutadi-ene and polyisoprene (1,2-PB/PI) and observed NOE cross-peaks between these component polymers. White and Mirau observed interpolymer NOE interactions between the H spins of PVME and the spins of deuterated... 

T02 Torrens, F., Soria, V., Monzo, I.S., Abad, C., and Campos, A., Treatment of poly(styrene-co-methacrylic acid)/poly(4-vinylpyridine) blends in solution under liquid-liquid phase-separation conditions. A new method for phase-separation data attainment from viscosity measurements, J. Appl. Polym. Sci., 102, 5039, 2006. 

Bisphenol A phenoxy polymers and bisphenol A polycarbonates were blended in solution. Chemical changes from aromatic to aliphatic carbonate groups were monitored by FTIR as a function of time and temperature (348). 

AHM Ahmed, A.A., Jayaraju, J., Sherigaia, B.S., Bhojya, H.S.N., and Keshavayya, J., Miscibility studies of dextran/poly(vinyl pyrrolidone) blend in solution, J. Macromol. Sci. Part A PureAppl. Chem., 45, 1055, 2008. 

There have been also some recent theoretical approaches addressing mainly the thermodynamic properties of binary and ternary polymer blends. Campos et al. (1996) extended the Flory-Huggins theory to predict the thermodynamic properties of binary polymer blends and blends in solution. Their approach was applied for PVDF/PS dry blend and in solutirm in dimethylformamide (DMF) with inclusion of an interaction functirai. It could be inferred that this blend behave as slightly incompatible under envirorunental cruiditions, in agreement with previously reported data. That incompatibility was suppressed when a low molar mass component, such as DMF, was added, reaching the semidilute regime (total... 

By thermally induced isomerization of an isoimide to an imide, a series of molecular composites with polyarylsulfone, polysulfone and an acetylene terminated isoimide thermosetting resin were obtained [37]. After two flexible polymeric compounds were blended in solution, films were cast and the isomerization process was carried out. The thermally treated films were insoluble and showed no sign of phase separation. 

CAM Campos, A., Gomez, C.M., Garcia, R., Figueruelo, J.E., and Soria, V., Extension of the Floiy-Huggins theory to study incompatible polymer blends in solution from phase separation data. Polymer, 37, 3361, 1996. 

Rajulu, A.V., and Reddy, R.L., and Siddaramaiah, J. (1998) Ultrasonic, refractometric, and viscosity studies of some polymer blends in solution. J. Appl. Polym. Sci., 70, 1823-1827. 

The phase diagram of a polymer blend in solution is obtained by equating the chemical potentials in the phases in equilibrium of the three components A, B and S or equivalently by equating the two exchange potentials and pg and the osmotic pressure. 

Cite in detail one examples each of what you feel are the most facile procedures for production of CP composites via blending in solution and in melt. 

In the literature various publications report that dissipative particle dynamics simulations are performed to systematically explore how the phase separated structures (core-shell or Janus) of a series of polymer blends in solution can be affected by the hydrophobicity and compatibihty difference among blended polymers and the solvent. 

Broseta, D., Quid Kaddour, L., Leibler, L., and Strazielle, C. 1987. A theoretical and experimental study of interfacial tension of immiscible polymer blends in solution. J. Chem. Phys. 87 7248-7256. 

The copolymers were blended in solution. The appropriate amounts of the constituents (v/v) were weighed and dissolved in xylene at 130 °C, maintaining the total concentration less than 1 wt%. The mixture was stirred continuously for 1 h after a homogeneous solution was obtained. Blends were precipitated by pouring the solution into chilled methanol. The mixture was centrifuged to obtain the solid blend. The blend was washed in acetone and dried in vacuum at 60 °C for 48 h or until a constant... 

Next, we derive the cross section of an isotopic polymer blend in solution. Again, we introduce occupation operators... 

---