Epoxy-terminated oligomers

Poly(unsaturated ester)-siloxane segmented copolymers have been prepared by the polycondensation of epoxy-terminated polydimethylsiloxanes and carboxy-terminated poly(ethylene adipate-co-maleate) oligomers 243). Reactions have been conducted in cellosolve solvent, at 140-150 °C, in the presence of 2% by weight potassium hydroxide catalyst. The molecular weights reported were fairly low. The same group has also prepared poly(hexamethylene adipate)-polydimethylsiloxane copolymers con-... 

Adhesive applications, thermosetting epoxy resin based on N-cyanourea-terminated oligomer, 107... 

Amino-terminated oligomers are used for hardening cyclocarbonate-terminated oligomers [29-31], Today, for thermostable epoxy compositions, aryl amines are used, which are toxic and require curing temperatures of more than 80°C. For thermostable epoxy and cyclocarbonate compositions, combinations of these oligomers are used with silicones [29],... 

Piperazine Capping of Epoxy Terminated Siloxane Oligomers... 

An additional way to produce a secondary amine group utilized the reaction of 8 moles of piperazine with 1 mole of the epoxy terminated siloxane oligomer. This reaction was conducted in di-oxane at 60° for about 24 hours. Excess piperazine was removed by washing the oligomer extensively with distilled water. Since the piperazine is water soluble and the oligomer is not, the final system was easily purified to very low levels of residual piperazine in this manner. The product was characterized by titration of the amine endgroups. 

The equilibration of the aminopropyl terminated disiloxane was conducted in a very similar manner to the epoxy terminated disiloxane and is shown in Scheme 5. The reaction in this case could not be followed by our GPC unit since we noticed significant absorption of the oligomers onto the columns. 

Figure 3. Comparison of the differential scanning photocalorimeter UV cure response of epoxy-terminated silicone oligomers with different chain lengths. The oligomers were cured using 0.5 mole % (4-octyloxyphenyl) phenyliodonium hexafluoroantimonate as photoinitiator.

The gas permeation parameters have also been reported for polymers obtained via ether reaction of epoxy and diamines [57,58], for polymer blends with acetylene-terminated oligomer [73,74] and internal acetylene polyimide [72,75]. The gas permeability of cross-linked internal acetylene-containing polymer, 6FDA-TeMPD/p-intA (4 1) declines from 612 to 186Barrer, while the selectivity, a(C02/CH4) increases from 14 to 25 at 35°C and lOatm [75]. Moreover, this cross-linked 6FDA-TeMPD/p-intA (4 1) membrane is still stable under CO2 pressure of about 47 atm. 

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