Poly siloxane aminopropyl-terminated

Table 10. Characteristics of aminopropyl-terminated poly(dimethyl-diphenyl)siloxane oligomers 66 171)...

The effect of structural variations in siloxane oligomers in the synthesis and properties of the resulting siloxane-urea copolymers have also been investigated 161). In these studies aminopropyl-terminated poly(dimethyl-diphenyl)siloxane and poly-... 

Poly(arylester)-polysiloxane multiblock copolymers have also been synthesized by the interfacial polymerization of aminopropyl terminated polysiloxane oligomers with bisphenol-A and a mixture of isophthaloyl and terephthaloyl chlorides117, 193-1951 as illustrated in Reaction Scheme XV. In these reactions the poly(arylester) blocks are formed in situ during the copolymerization, so the control of their block sizes is not very precise. It is also important to note that since aminopropyl terminated siloxane oligomers are employed, the linkages which connect the arylester and siloxane blocks are amide linkages. 

In this paper we will discuss the synthesis of a, urhydroxybutyl terminated polydimethylsiloxane oligomers by cationic routes and a,u-aminopropyl terminated poly(dimethy1-diphenyl)siloxane oligomers by anionic methods respectively. Detailed procedures for the synthesis of aminopropyl, carhoxypropyl and glycidoxypropyl terminated polydimethylsiloxane oligomers have already been described elsewhere(1 1). ... 

Table II provides a summary of the results on the characteristics of aminopropyl terminated poly(dimethyl-diphenyl)-siloxane oligomers synthesized. These reactions were conducted in bulk at 160°C with K0H as the initiator. As can be seen from Table II the stoichiometric number average molecular weights sought and obtained are in very good agreement. The level of diphenylsiloxane incorporation was determined by UV spectroscopy. There is no absorption of dimethylsiloxane backbone in the spectral range of 240 to 280 nm. On the other hand, phenyl groups absorb very strongly over these wavelengths (Figure 3). For quantitative analysis we have used the absorption peak at 270 nm as the reference.

Characteristics of Aminopropyl Terminated Poly(Dimethyldiphenyl)siloxane Oligomers... 

The traditional approach used in poly(imide-siloxane) synthesis is the reaction of aminopropyl-terminated dimethylsiloxane oligomers with aromatic dianhydrides and additional diamines (9-13). Typically, subambient temperatures and dipolar aprotic solvents are used. The resulting high-molecular-weight polyamic acid solution can be heated to effect imidization and solvent evaporation. This procedure is analogous to the synthetic method used to prepare conventional polyimides for films and coatings. 

Scheme 9.4 General schematic of the synthesis of aminopropyl-termin-ated poly(dimethyl)-co-(diphenyl)siloxane (Elsbernd, 1988).

Figure 9.28 Cel permeation chromatograms of a 5,000 molecular weight aminopropyl-terminated poly-(dimethyD-co-(diphenyl)siloxane parent copolymer containing 25wt% diphenyl substituents and of fraction 2 obtained with supercritical ethane at 150°C and 300 bar after reaction with supercritical carbon dioxide at 80°C and 100 bar (refer to data in table 9.17) (Elsbernd et al., 1990b).

Tensile strength MPa Aminopropyl terminated poly(dimethyl siloxane) 16.6 (14)... 

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