Random copolymers tension

The polymeric dispersants included random copolymers of long chain alpha olefins or long chain methacrylates with acidic or basic co-monomers such as vinyl acetate, vinyl alcohol, vinyl pyridine, vinyl pyrollidone, hydroxyethyl methacrylate, etc. The alpha-olefin vinyl acetate copolymers had molecular weights in the 1-25,000 range and the methacrylates were in the 100,000 + range. All were oil soluble and reduced the oil-water interfacial tension appreciably. 

Figure 18.12. Predicted solubility parameter (thin line, left-hand y-axis, from the Fedors-like cohesive energy Ecohl) and surface tension (thick line, right-hand y-axis, from generalized molar parachor) of amorphous random copolymers of styrene and oxytrimethylene at room temperature, as functions of the composition.

The main peculiarities of phase separation of polyampholytes - random copolymers of 2M5VP-AA that are insoluble at the lEP - were considered by authors [63-65] from the colloid chemical point of view. Tables 7 and 8 summarize some physico-chemical characteristics of polyampholytes used. The surface tension O, viscosity [rj] and electro conductivity x of PA-3 solution and dispersion are minimal at the lEP (Fig. 13). In the semilogarithmic coordinates the dependence of surface tension o on IgC has breaking points. They correspond to the critical concentration of polyampholytes that reflects the saturation of the adsorp-... 

SCH Schneider, A. and Wolf, B.A., Specific features of the interfaeial tension in the case of phase separated solutions of random copolymers. Polymer, 41,4089, 2000. 

SHA Sharma, S.C., Acharya, D.P., Garcia-Roman, M., Itami, Y., and Kunieda, H., Phase behavior and surface tensions of amphiphilic fluorinated random copolymer aqueous solutions, Coll. Surfaces A, 280, 140, 2006. 

FU2 Funke, Z., Hotani, Y., Ougizawa, T., Kressler, J., and Kammer, H.-W., Equation-of-state properties and surface tension of ethylene-vinyl alcohol random copolymers (experimental data by Z. Funke), Eur. Polym. J., 43, 2371, 2007. 

PVT data for polymers are important both from the academic and practical points of view. On the scientific side, PVT data are frequently needed for model considerations on polymer solutions and melts. On the industrial side, these data are needed for process design. An equally important thermodynamic quantity is the surface tension of polymer melts, due to their relevance in wetting, adsorption, and adhesion. It may strongly govern such surface processes as film formation or coating. Here we report on PVT data and surface tensions of different random copolymers. We also relate thermodynamic quantities describing bulk properties to surface tension of polymer melts. 

Here we test Eq. (8.30) for random copolymers by plotting surface tension versus pIk) I (Figure 8.17). The linear regression curve (correlation 0.9999) results for EVOH copolymers. It has the slope... 

FIGURE 8.17 Surface tension of the random copolymers as a function of p and... 

Menke, T. J., Funke, Z., Maier, R. D., and Kressler, J., Surface tension measurements on ethane-butene random copolymers and different polypropenes, J. Macromolecules, 33, 6120-6125 (2000). 

At each point of the surface the interaction is proportional to the polymer density (p, with proportionality constant o(r) (the "surface parameter ). Thus at points where o>0, B monomers are preferred A monomers are preferred if a<0 (10). This surface tension can be tuned, for example, by coating the surface with random copolymers (11). We restrict ourselves for one planar sur ce located at z=0, see Figure 1. 

SURFACE TENSION OF POLYMER BLENDS AND RANDOM COPOLYMERS... 

Most of the polymers are veiy viscous even at high temperatures. Moreover, they exhibit non-Newtonian flowing behavior. Considerable care is required to ensure precise measurements. We will discuss here surface tensions of polymer blends and of random copolymers especially, we will focus on its variation with composition. 

Surface Tension of Polymer Blends and Random Copolymers... 

Rastogi and St.Pierre (Rastogi and St.Pierre, 1969) compared random copolymers of ethylene oxide and propylene oxide with miscible blends of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO). In the original paper, they claimed linear variation of surface tension of the random copolymer with composition ... 

We discuss variation of surface tension of blends and random copolymers with composition in terms of a generalized Langmuir adsorption isotherm. The partition coefficient in surface and bulk might be expressed by equilibrium of occupancy of the surface region by segments of types 1 and 2 as follows ... 

The composition dependence of surface tension of a random copolymer was already discussed in Figure 2 of Paragraph 9.2. This copolymer showed negative deviation from linearity with respect to compositioa... 

The random copolymer poly(ethylene-co-viityl alcohol) (EVOH) varies linearly with copolymer composition although there is a remarkable difference in surface tension of the parent polymers ... 

Very special behavior is displayed by the random copolymer poly(ethylene-co-vinyl acetate) (EVAc) (Hata, 1968) due to the fact that the parent polymers have very similar surface tension ... 

We tested if the random copolymers under discussion obey relationship Equation (21) by plotting surface tension versus at temperatures as mentioned... 

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