Poly blend composite

Kruse, R. (1979) Polymeric poly blend compositions toughened by addition of liquid polymers of a conjugated diene monomer , U.S. Patent 4,154,715. 

Unlike most crystalline polymers, PVDF exhibits thermodynamic compatibiUty with other polymers (133). Blends of PVDF and poly(methyl methacrylate) (PMMA) are compatible over a wide range of blend composition (134,135). SoHd-state nmr studies showed that isotactic PMMA is more miscible with PVDF than atactic and syndiotactic PMMA (136). MiscibiUty of PVDF and poly(alkyl acrylates) depends on a specific interaction between PVDF and oxygen within the acrylate and the effect of this interaction is diminished as the hydrocarbon content of the ester is increased (137). Strong dipolar interactions are important to achieve miscibility with poly(vinyhdene fluoride) (138). PVDF blends are the object of many papers and patents specific blends of PVDF and acryflc copolymers have seen large commercial use. 

Other blends such as polyhydroxyalkanoates (PHA) with cellulose acetate (208), PHA with polycaprolactone (209), poly(lactic acid) with poly(ethylene glycol) (210), chitosan and cellulose (211), poly(lactic acid) with inorganic fillers (212), and PHA and aUphatic polyesters with inorganics (213) are receiving attention. The different blending compositions seem to be limited only by the number of polymers available and the compatibiUty of the components. The latter blends, with all natural or biodegradable components, appear to afford the best approach for future research as property balance and biodegradabihty is attempted. Starch and additives have been evaluated ia detail from the perspective of stmcture and compatibiUty with starch (214). 

Poly- anion Blend No. Composition of Polyanion Blend Composition of Polycation Blend Poly- cation Blend No. 

The effect of annealing temperatures (65 - 250 °C) and blend composition of Nafion 117, solution-cast Nafion , poly(vinyl alcohol) (PVA) and Nafion /PVAblend membranes for application to the direct methanol fuel cell is reported in [148], These authors have found that a Nafion /PVAblend membrane at 5 wt% PVA (annealed at 230 °C) show a similar proton conductivity of that found to Nafion 117, but with a three times lower methanol permeability compared to Nafion 117. They also found that for Nafion /PVA (50 wt% PVA) blend membranes, the methanol permeability decreases by approximately one order of magnitude, whilst the proton conductivity remained relatively constant, with increasing annealing temperature. The Nafion /PVA blend membrane at 5 wt% PVA and 230 °C annealing temperature had a similar proton conductivity, but three times lower methanol permeability compared to unannealed Nafion 117 (benchmark in PEM fuel cells). 

Coleman et al. 2471 reported the spectra of different proportions of poly(vinylidene fluoride) PVDF and atactic poly(methyl methacrylate) PMMA. At a level of 75/25 PVDF/PMMA the blend is incompatible and the spectra of the blend can be synthesized by addition of the spectra of the pure components in the appropriate amounts. On the other hand, a blend composition of 39 61 had an infrared spectrum which could not be approximated by absorbance addition of the two pure spectra. A carbonyl band at 1718cm-1 was observed and indicates a distinct interaction involving the carbonyl groups. The spectra of the PVDF shows that a conformational change has been induced in the compatible blend but only a fraction of the PVDF is involved in the conformational change. Allara M9 250 251) cautioned that some of these spectroscopic effects in polymer blends may arise from dispersion effects in the difference spectra rather than chemical effects. Refractive index differences between the pure component and the blend can alter the band shapes and lead to frequency shifts to lower frequencies and in general the frequency shifts are to lower frequencies. 

Strength of the specific interaction. An example of this is shown in Fig. 9 for blends of poly(butyl acrylate) with chlorinated polyethylene. In this case the blend requires a higher activation energy than its additivity value in the form of heat to allow chain movements. A review of this subject and of the relations between and chemical structure of blends has been given by Cowie For miscible blends many attempts have been made to correlate the with the blend composition as is frequently done with random copolymers. Several miscible blends studied by Hammer and Hichman and Ikeda exhibit a composition dependence of which can be described by the simple Fox relationship. 

In this entry, the effect of blending recyclable poly-(propylene) (PP) and poly(ethylene terephthalate) (PET) with lignin on carbon fiber production is presented. We discuss the effects of lignin structure and specific intermolecular interactions on lignin thermal properties as well as the effect of blend composition on surface morphology, mechanical properties, and the manufacturing process of lignin/recyclable plastic-based carbon fibers. 

The miscibility of poly(4-vinylpyridine) (P4VP) with poly(4-vinylphenol) (PVPh) blends was investigated over a wide range of compositions by other techniques and high-resolution solid-state NMR. ° Relaxation times were studied as a function of blend composition. Ti(H) and Tip(H) results demonstrate that the spin diffusion can completely average out the entire relaxation process. It was also found that the intimate mixing of the polymer blends restricts the local chain mobility. 

On the basis of a systematic study of the emulsifying effect of block copolymers in PS-PI and in polystyrene-poly (methyl methacrylate) (PS-PMM) polyblends (3), it was possible to represent schematically the appearance of the films for different blend compositions as functions of molecular weight and composition of the block copolymer (Cop), as well as of molecular weight of the homopolymers (see Figure 2). Thus in a polyblend containing PS and PI of practically the same molecular weight — M2), the best... 

Elemental analysis (EA) is a convenient method for determination of copolymer and blend composition if one homopolymer contains an element not present in the second one. For example, EA can be properly used to quantify nitrogen in copolymers containing acrylonitrile units and oxygen in polymeric surfactants such as poly(oxy-alkylene). Therefore, for a binary system, every element can be balanced according to the following equation ... 

Figure 14.8 Two plots which summarize the influence of blend composition on the drying rates for mixtures of hard and soft latex particle dispersions. The hard latex is poly (methyl methacrylate) (d = 110 nm), and the soft latex is poly-[(butyl methacrylate) o-(hutyl acrylate)] (d = 43 nm, Tg = —33 C). Each data point represents a snapshot of the drying process, (a) refers to the instantaneous rate of water evaporadon at SO wt%, 7S wt% and 90 wt% solids, for blends cotiprising different volume fracdons (4 hud) of hard latex, (b) refers to the time needed for the dispersions, originally at S wt% to reach SO wt%, 7S wt% and 90 wt% solids at 22 °C, 50% reladve humidity in sdll air. Both plots indicate that c. 1 1 mixtures dry at the slowest rate...

Blends of polystyrene(PS) and poly(vinyl methyl ether) (PVME) have attracted much interest because of their compatibility over a wide range of blend composition . The compatibility of PVME with styrenic copolymers has also been extensively investigated. 

PVME with PS, P(S9-co-oMeSl), P(S9-co-mMeSl), or P(S9-co-pMeSl). It is to be noted that the cloud points of mixtures containing copolymers are all lower than those containing PS at all blend compositions, and the compatibility with PVME of copolymers containing styrene derivatives diminishes in the order poly(styrene-co-o-methylstyrene) > poly(styrene-co-p-methylstyrene) > poly(styrene-co-m-methylstyrene). The same trend can be observed in the cloud point data of blends of PVME with styrene derivative copolymers having the composition 80/20(by monomer feed ratio), as can be seen in Figure 3. 

In practice, the techniques of blending, compositing and nano-reinforcement are often used together. Thermoplastic starch/poly(vinyl alcohol) (PVOH)/clay nanocomposites exhibited the intercalated and exfoliated structures [260]. Mont-morillonite (MMT) with three types of cation or modifier (Na", alkyl ammonium ion, and citric acid) was examined. The prepared nanocomposites with modified montmorillonite indicated a mechanical improvement in the properties, in comparison with pristine MMT. 

Yoshie, N., Azuma, Y., Sakurai, M., and Inoue, Y., 1995, Crystallization and compatibility of poly(vinyl alcohol)/poly(3-hydroxybutyrate) blends influence of blend composition and tacticity of poly(vinyl alcohol). Appl. Polym. Sci. 56 17-24. 

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