Ether-thioether copolymers

SULFUR-SUB STITUTED POLYOXYETHYLENE S SEQUENTIAL ETHER-THIOETHER COPOLYMERS... 

Investigations of the parent homopolymers, homologous analogs and some sequential ether-thioether copolymers have been reported. 5-10 These have led to a clearer understanding of the fundamental differences in behavior resulting from basic molecular dimensions and inter- and intramolecular interactions. We previously reported an efficient general synthesis of sequential ether-thioether copolymers which made available a wide variety of... 

C. Copolymers with Ether-Thioether and Amine-Thioether Spacers... 

The photoinduced polymerization of propylene oxide from the living polymer of propylene sulfide initiated with 2b (2a, R = Me) was successful to give poly(thioether) - poly(ether) block copolymer with narrow molecular weight distribution. 

These include copolymers of propylene sulphide with 3-10% of allyl glycidyl thioether and which may be considered as a thio-analogue of the propylene oxide-allyl glycidyl ether rubber briefly mentioned in Section 19.5 ... 

In an extreme case the reactivity difference between the two monomers is positively utilized to obtain block copolymers. For example, Goethals recently polymerized IBVE with CF3S03H in the presence of thietane (a cyclic thioether) [86]. Because the thioether is much less reactive than vinyl ethers, it cannot polymerize and serves as a nucleophilic additive in the first-phase vinyl ether polymerization [64], but once IBVE has been completely polymerized, the cyclic monomer now polymerizes from the living end to form block polymers. 

Table 22 lists four polymer series of PEIs which contain an ether, sulphone or carbonyl linked diphenyl tetracarboxylimide unit [36]. Each of the four series contains two imide and two ester groups and have four aromatic co-monomers. Polymer series 7 and 9 also contain two units of p-aminophenol in conjunction with a bicyclic aromatic dicarboxylic acid, whereas polymer series 6 and 8 are based on m-aminophenol. The Mesogenic Index correctly predicts that series 6, 8 and 9 give rise to isotropic copolymers. However, in the case of series 7, in which the variable monomer was based on ether or thioether diphenol derivatives, thermotropic phases were observed in all three cases. When all four series are viewed as a whole it is clear that an MI value of 9.5 represents a borderline condition for a mesophase to occur. It also corresponds with the minimum value for a mesophase observed in NCPT-based PEIs. 

In order to complete the electrochemical investigations, the redox properties of the copolymers were also studied." The cyclic voltammogram of polymer 19a, containing aromatic ether and thioether bridges was examined. Figure 15 shows the CV obtained at -30°C using a scan rate of 1 V/s. The pc Epa, and E1/2 for this polymer were calculated to be 1.23, 0.955, and -1.09X respectively. 

Styrene substituted in the position with various alkyl ether or thioether residues 10, i.e., 2-phenylvinyl alkyl ethers or thioethers, easily copolymerize with MA to give equimolar copolymers. The copolymers... 

Molecular weights increased with conversion in the phenylvinyl alkyl ether-MA copolymerizations. Under comparable conditions, lower copolymer yields were obtained for the vinyl thioether-MA pairs. Yields and molecular weight, in both cases, were shown to be highest when equimolar amounts of... 

When copolymers are prepared by ring opening polymerization of chiral monomers such as cyclic ethers and thioethers, lactones, lactams, N-carboxy anhydrides, etc., the chirality of the monomers is often retained in the repeating groups incorporated into the copolymers. A few stereoregular copolymers prepared this way have been analyzed by nmr spectroscopy, but much remains to be done in this area. 

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