Poly substituted homopolymers

Poly(U) with 2 -OH substituted by 2 -NH2, and poly(I) and poly(C) with 2 -OH substituted by 2,-0-CO-CH3 l avc not been incorporated, because they failed to form regular duplexes with the complementary homopolynucleotides83, 164). The 2 -NH2 and 2 -0-C0-CH3 substituted homopolymers were devoid of any significant antiviral activity 9, 83),... 

Huang s group has systematically studied the structure-property relationships of fluorene-thiophene-based conjugated polymers 57-60 [95, 96], In contrast to poly thiophene homopolymers, the regiochemistry of substitution in bithiophene fragments in the studied copolymers shows little effect on the optical bandgap (59 and 60, respectively Eg = 2.49 and 2.58 eV [96] or 2.57 and 2.60 eV [97, 98]) or the emission maxima, but the head-to-head copolymer 60 was significantly more thermally stable. 

The structure of polysilylenes has also been explored with H, and NMR methods. " The studies indicate that polysilylene chain configurations in solution are varied and quite complex for a wide range of asymmetrically substituted homopolymers and copolymers. Thus, at high field (500 MHz) the alkyl protons in poly(methyl-n-hexylsilylene) are well resolved and assigned using 2D spectra. The spectra provide information about the microstructure and the Si spectra appear sensitive to stereochemical configuration at least to the pentad level. 

Materials. PCPP was synthesized from soluble poly(dichlorophosphazene), (PNCl2)n, which was prepared by the thermal ring opening of hexachlorocyclo-triphosphazene, N3P3CI6 (9). The poly(dichlorophosphazene) dissolved in benzene solution was reacted with the sodium salt of p-chlorophenoxide, which was prepared by reaction of sodium and p-chlorophenol in a 2-ethoxyethyl ether / 1,4-dioxane cosolvent system, to form a fully substituted homopolymer, [PN(OC6H5Cl)2]n, PCPP, as reported by Reynard et al.(27). The product, PCPP, was then isolated and purified... 

The major use of vinylpyrrohdinone is as a monomer in manufacture of poly(vinylpyrrohdinone) (PVP) homopolymer and in various copolymers, where it frequendy imparts hydrophilic properties. When PVP was first produced, its principal use was as a blood plasma substitute and extender, a use no longer sanctioned. These polymers are used in pharmaceutical and cosmetic appHcations, soft contact lenses, and viscosity index improvers. The monomer serves as a component in radiation-cured polymer compositions, serving as a reactive diluent that reduces viscosity and increases cross-linking rates (see... 

Previous work on the synthesis of TTF (tetrathiafulvalene) containing polymers has been reported by at least seven groups of researchers. Most of this work concerns condensation 6,7,8,9 polymers or polymers made from vinyl substituted TTF molecules . Without exception, the polymers produced by these methods have been largely unacceptable for subsequent physical study because of their brittle,intractable, highly insoluble nature. Only by reaction of a suitably monofunctionalized TTF derivative with the preformed polymer poly(vinylbenzylchloride) has it been found possible — to prepare soluble TTF homopolymers with more manageable physical properties. 

Sulfonated poly(4-substituted benzoyl-1,4-phenylene) homopolymers and copolymers using concentrated sulfuric acid or fuming sulfuric acid have been shown to form sulfonated polymers with variable degrees of sulfonation. To improve film formation of the sulfonated polyphenylenes, multiblock copolymers have been synthesized by reacting a more flexible poly(arylene ether sulfone) with sulfonated poly-phenylenes. ... 

Incompatible Mixtures. Even at very low levels, many of the poly-ether additives led to incompatible mixtures. These blends were not successfully milled to a smooth sheet under any conditions tried. Instead, a mass of crumbs was obtained. These crumbs could be molded into a coherent mass, but the physical properties were poor. For example, addition of 8.75 parts of polybutene-1 oxide to Masterbatch B for CPVC alone gave a brittle, free-flowing material with these properties notched Izod impact strength, 0.7 lb/in notch, flow rate 452 g/10 min. This is a particularly interesting result, since PBO has the same chemical formula as PTHF but structurally is a substituted ethylene oxide polymer rather than a linear homopolymer. No further studies were made of such blends. 

It was known that polystyrene and poly- >-methoxystyrene initiated by tin tetrachloride have a branched structure, due to aromatic substitution in the course of the polymerization (186). Haas, Kamath and Schuler (93, 124) studied the ionic chain transfer reaction between a polystyrene carbonium chain and poly-/>-methoxystyrene. They were able to separate the homopolymers from the graft copolymers by extraction with methylcyclohexane. 

Glucose Sensors. Siloxane polymers are known to be extremely flexible. This flexibility will, of course, be sensitive to the amount of side-chain substitution present along the polymer backbone. For instance, in the homopolymer used in these studies (polymer A), the presence of a ferrocenylethyl moiety bound to each silicon subunit should provide an additional degree of steric hindrance, and thus a barrier to rotation about the siloxane backbone, in comparison with the copolymers, which have ferrocene relays attached to only a fraction of the Si atoms. Because these siloxane polymers are insoluble in water, their flexibility is an important factor in their ability to facilitate electron transfer from the reduced enzyme. Relays contained within more rigid redox polymers, such as poly(vinylferrocene), cannot achieve close contact with the enzyme s redox centers and are thus less effective as electron transfer mediators (25,34). The importance of this feature can be seen quite clearly by comparing the mediating ability of the homopolymer A with that of copolymers B-D, as shown in Figures 4 and 5. 

Effects of additives in the matrix were observed by substituting for methyl methacrylate a poly (methyl methacrylate) homopolymer with a solution molecular weight of 950,000, a vinylidene fluoride copolymer (Pennwalt s Kynar 7201), and a methacrylate-butadiene-styrene impact modifier (Marbon s Blendex BTA IIIN). Concentrations were 2% on the total dispersion volume. The same additives were studied at the same volume concentration in the dispersed phase. Barium sulfate (Whittaker, Clark, and Daniels Barytes No. 91), a commonly used additive for radiopacity, was also studied in the dispersed phase. Responses were observed by the test methods described below. 

One of the earliest examples of photodecomposable, but thermally stable, polymeric systems contains pendant perester substituted benzophenone moieties, the photodissociation of the former group being promoted by the benzophenone chromophore which behaves as a triplet sensitizer. Indeed, the homopolymer of 4-vinylbenzoyl-4 -tert-butyl perbenzoate and its copolymers with styrene [poly(VBPE) and poly(VBPE-co-St), respectively] have been prepared and checked as photoinitiators in the polymerization of styrene and MMA by irradiation at 366 nm [79,80]. 

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