Morphology observations poly

Kobayashi, T, Wood, B.A., Takemura, A., and Ono, H. (2006) Antistatic performance and morphological observation of ternary blends of poly (ethylene terephthalate), poly(ether esteramide), and Na-neutralized poly (ethylene-co-methacrylic acid) copolymers. J. Electrostat., 64,... 

Similarly, as shown in Figure 6, the morphology of poly-R/poly-S binary mixtures of PMEPL is controlled by the formation of the stereocomplex at high temperatures, followed by the crystallization of the excess polymer at lower temperatures. It is believed that the excess polymer is trapped between the spherulite lamellae of the stereocomplex, and at their boundaries. Large spherulites are then observed for the racemate sample, and for all binary mixtures in which the stereocomplex can be formed, but very small spherulites are found for pure isotactic chains. 

In a real polymer system, the chain will attempt to crystallize in the lowest energy state. The lowest energy state for a polymer such as poly(methylene) will be an extended all-trans structure. Studies of single crystals of poly(methylene) formed from dilute solution resemble the predicted structure of a single crystal however, there are a number of other factors which will influence the nature of the crystal structure or morphology observed. It is appropriate to divide polymers into various types depending on their chemical repeat unit. 

Two phase morphology and positive Flory Huggins parameters %i2 were observed for PHB/poly (vinyl butyral) (PVB), a random copolymer of vinyl butyral and vinyl alcohol of different compositions). It was found that a degree of immiscibility (as characterized by X12 values) depends on PVB composition with partial nndscibility and co-continuous morphology observed for a 50/50 blend and 25 - 36 vinyl alcohol content in PVB. The results are interpreted in terms of repulsive effect of hydrophobic and hydrophilic component in PVB [63]... 

Paine et al. [99] tried different stabilizers [i.e., hydroxy propylcellulose, poly(N-vinylpyrollidone), and poly(acrylic acid)] in the dispersion polymerization of styrene initiated with AIBN in the ethanol medium. The direct observation of the stained thin sections of the particles by transmission electron microscopy showed the existence of stabilizer layer in 10-20 nm thickness on the surface of the polystyrene particles. When the polystyrene latexes were dissolved in dioxane and precipitated with methanol, new latex particles with a similar surface stabilizer morphology were obtained. These results supported the grafting mechanism of stabilization during dispersion polymerization of styrene in polar solvents. 

In the sol-gel procedure for the preparation of hybrids, polymeric acid catalysts such as poly (styrene sulfonic acid) were also used instead of hydrogen chloride [14]. The polymeric acid catalyst was effective for the preparation of hybrids at a similar level to that of hydrogen chloride catalyst. In some cases, the increased modulus was observed due to the higher extent of reaction. No difference was observed in morphologies between the hybrids prepared with polymeric and small molecule acid catalysts. The method using polymeric acid catalyst may depress the ion-conductive property, characteristic to the mobile acidic small molecules. Polymeric catalyst may also influence the rheology of the resulting hybrids. 

Hedrick et al. reported imide aryl ether ketone segmented block copolymers.228 The block copolymers were prepared via a two-step process. Both a bisphenol-A-based amorphous block and a semicrystalline block were prepared from a soluble and amorphous ketimine precursor. The blocks of poly(arylene ether ether ketone) oligomers with Mn range of 6000-12,000 g/mol were coreacted with 4,4,-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) diethyl ester diacyl chloride in NMP in the presence of A - me thy 1 morphi 1 i nc. Clear films with high moduli by solution casting and followed by curing were obtained. Multiphase morphologies were observed in both cases. 

Tian et al. [56] have studied poly(G-caprolactone)-silica and Sengupta et al. [57] have investigated nylon 66-silica hybrid systems and have observed that the phase separation started when Si/H20 mole ratio is increased above 2 and the resultant hybrid films become opaque. Gao [11] has reported similar observations on sol-gel-derived ionomeric polyethylene-silica system. A wide range of literatures is not available on this topic of mbber-silica hybrid nanocomposites, though Bandyopadhyay et al. [34,35] have reported the hybrid formation with different TEOS/H2O mole ratios from ACM and ENR and also demonstrated detailed structure-property correlation in these systems. The hybrids have been prepared with 1 1, 1 2, 1 4, 1 6, 1 8, and 1 10 TEOS/H2O mole ratios. Figure 3.14 shows the morphology of the ACM-silica hybrid composites prepared from different TEOS/H2O mole ratios. 

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