Poly polymers first example

This review has shown that the analogy between P=C and C=C bonds can indeed be extended to polymer chemistry. Two of the most common uses for C=C bonds in polymer science have successfully been applied to P=C bonds. In particular, the addition polymerization of phosphaalkenes affords functional poly(methylenephosphine)s the first examples of macromolecules with alternating phosphorus and carbon atoms. The chemical functionality of the phosphine center may lead to applications in areas such as polymer-supported catalysis. In addition, the first n-conjugated phosphorus analogs of poly(p-phenylenevinylene) have been prepared. Comparison of the electronic properties of the polymers with molecular model compounds is consistent with some degree of n-conjugation in the polymer backbone. 

The first example will deal with polymer blends consisting of polyamide (PA) and poly(tetrafluoroethylene) (PTFE). These polymer types are frequently used... 

In the first case, the reactions occurred with quite good yields of polymers, for example, polyadenosine [poly(A)], which was precipitated from the micelles. 

We have reported the first example of a ring-opening metathesis polymerization in C02 [144,145]. In this work, bicyclo[2.2.1]hept-2-ene (norbornene) was polymerized in C02 and C02/methanol mixtures using a Ru(H20)6(tos)2 initiator (see Scheme 6). These reactions were carried out at 65 °C and pressure was varied from 60 to 345 bar they resulted in poly(norbornene) with similar conversions and molecular weights as those obtained in other solvent systems. JH NMR spectroscopy of the poly(norbornene) showed that the product from a polymerization in pure methanol had the same structure as the product from the polymerization in pure C02. More interestingly, it was shown that the cis/trans ratio of the polymer microstructure can be controlled by the addition of a methanol cosolvent to the polymerization medium (see Fig. 12). The poly(norbornene) prepared in pure methanol or in methanol/C02 mixtures had a very high trans-vinylene content, while the polymer prepared in pure C02 had very high ds-vinylene content. These results can be explained by the solvent effects on relative populations of the two different possible metal... 

Recently, the first example of chiral solvation of a polysilane was demonstrated dissolution of the inherently optically inactive poly(methylphenylsilyene), PMPS, and poly(hexylmethylsilylene), PHMS, in the optically active solvents (V)-2-methyl-l-propoxybutane and (V)-(2-methylbutoxymethyl)benzene induced the polymer chains to adopt PSS helical conformations as evidenced by (positive-signed) Cotton effects almost coincident with the UV a-a transition at 340 and 305 nm, respectively.332... 

Another result of great importance—the conformational asymmetric polymerization of triphenylmethyl methacrylate realized in Osaka (223, 364, 365)— has already been discussed in Sect. IV-C. The polymerization was carried out in the presence of the complex butyllithium-sparteine or butyllithium-6-ben-zylsparteine. The use of benzylsparteine as cocatalyst leads to a completely soluble low molecular weight polymer with optical activity [a]o around 340° its structure was ascertained by conversion into (optically inactive) isotactic poly(methyl methacrylate). To the best of my knowledge this is the first example of an asymmetric synthesis in which the chirality of the product derives finom hindered rotation around carbon-carbon single bonds. 

In 1990, Wong disclosed in a patent literature that a propylene/CO alternating co-polymer arising from a Pd-based catalyst and (—), 5-bis(dibutylphosphinomethyl)-2,2-dimethyl-l,3-dioxolane as a chiral ligand displayed a specific rotation of 10.4 in (CF3)2CHOH. This represents the first example of asymmetric alternating co-poly-... 

The first example of catalysis by a polymer-metal complex was presented by Lautsch et al. u3 Metalloporphyrin was linked to a poly(phenylalanine) chain by a peptide bond. The catalytic properties of this polymer-Fe(III)porphyrin complex were compared with Fe(III)porphyrin in the oxidative reaction of phenylenedi-amine. The catalytic activity of the polymer complex was twice as large as that for the corresponding analog. 

More recently, Chen et al. described a surface modification whereby the polymer poly(Ar,Ar-dimethyl-Af-(ethoxycarbonylmethyl)-Ar-[2/-(methacryloyloxy)ethyl]-ammonium bromide) was grafted from a surface via ATRP [136], The cationic polymer effectively kills E. coli and is subsequently converted into a zwitterionic polymer by hydrolysis of the head group (Fig. 9). It then repels all attached cells dead or alive. This is the first example of a surface that can kill microbes on contact and repels them after that. The only downside of this elegant system is that it will eventually exhaust and turn into a more or less effective repelling surface. 

The second method involves substitution reactions on a preformed polymer with a stiff backbone. The advantage of this method is that it provides better control over the MW of the starting polymer. However, the substitution may not be 100%. The first example involved the substitution on a poly( 1,1,1-propellane) copolymer [116]. A copolymer with 80% functionalizable units has been successfully modified with a [G-1]-Br poly(benzyl ether) dendron (see Scheme 13a). Further studies exploring the feasibility and steric limitations of the substitution route have been performed on poly(p-phenylene) [113, 116]. The Williamson substitution reaction on... 

Several biopolymers and synthetic optically active polymers are known to exhibit an inversion of helicity (helix-helix transition) between right- and left-handed helical conformations when changing the external conditions, such as solvent, temperature, or by light irradiation. However, switching of the macromolecular helicity by chiral stimuli is rare, and can be used to sense the chirality of specific chiral guests. The helicity of optically active helical poly(phenylacetylene)s 67-69 can be switched by external chiral and achiral stimuli [123-126]. The first example of such a helix inversion induced by... 

Poly(ethylenimine) (PEI) has been examined extensively both in its classical, random branched topology [125] and in its linear form [126]. The various architectural and topological forms of PEI have been reviewed recently [127], Here we describe the first example of this polymer system as an ideal, hyper-branched molecular assembly. Synthesis of a tri-dendron poly(ethyleneimine) dendrimer derived from an ammonia core involved, first the selective alkylation of diethylenetriamine (DETA) with aziridine to produce a symmetrical core cell, namely tris-(-2-aminoethyl)amine. Subsequent exhaustive alkylations of the terminal amino moieties with activated aziridines [2, 127, 128], such as IV-tosyl- or N-mesylaziridine gave very good conversions to the first-generation protected... 

Metal-poly-yne polymers other than Pt-D1 polymer also form liquid crystals. They may be the first example of lyotropic liquid-crystalline materials having transition metals. 

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