Siloxane Copolymers by Ring-Opening Polymerization

AB and difunctional oligomers leading to ABA types of structures. The molecular weight control of the growing segments is achieved by the ratio of the cyclic monomer to the oligomeric initiator in the original reaction mixture. 

Very recently the synthesis of BA and ABA type polyoxazoline(B)-polydimethyl-siloxane(A) block copolymers have been demonstrated 290,291). These types of materi- 

Synthesis of Poly(2-ethyl-2-oxazoline)-b-PDMS (ABA) Block Copolymers 2911 

Synthesis of PDMS-b-(e-caprolactam) ABA block copolymers was reported 343 In these reactions, anhydride-terminated PDMS oligomers were used to initiate the polymerization of -caprolactam in the presence of a catalytic amount of sodium hydride in melt at 130 °C. Under these conditions, the reaction was reported to be completed in 

2 minutes, resulting in the formation of high molecular weight polymers in high yields. The copolymers obtained were soluble in m-cresol. DSC analysis showed the formation of two-phase polymer morphologies. 

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