Anionic ring-opening polymerization molecular weight

The anionic ring-opening polymerization of 118178 was carried out with the use of tetrabutylammonium fluoride (2 mol%) as catalyst in THF to give rise to the poly[(disilanylene)ethynylenes] 119 with high molecular weights. 

Polydimethylsiloxane (PDMS) was synthesized from the cyclic trimer hexa-methyltrisiloxane D3 in hexane using anionic ring-opening polymerization and dilithium stilbene as initiator (7). This material was terminated by chlorovinyldi-methylsilane at a molecular weight Mw of 60,000. It was then precipitated from... 

Efficient methods for the synthesis of cyclic bisphenol-A polycarbonates have provided a practical technology for the rapid synthesis of high molecular weight bisphenol-A polycarbonates by anionic ring-opening polymerization as shown in Equation 7.29 [150]. A mixture of cyclic oligomers (M 1300) was polymerized with lithium... 

Recently, an ambient-temperature sonochemical reductive coupling process was developed. The reaction is carried out in the presence of an ultrasound and results in relatively high (Mn = 50,000-100,000) molecular weight materials with narrow molecular weight distributions. In addition, it was reported that polymers can also be formed by anionic ring-opening polymerization of... 

They are unstable at these temperatures and cannot be melt spun. Fibers, however, were prepared by dry spinning from hydrocarbon suspensions [49]. Later, it was found that when the anionic ring opening polymerizations of 2-pyrrolidone are activated by CO2 in place of the iV-acyl derivative, the resultant higher molecular weight product has much better heat resistance [54]. This new nylon 4, reportedly, can be melt spun. 

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