Ring-opening polymerisation molar mass

Stoessel [87] has reported using ultrasound to promote the ring opening of polycarbonate rings (Fig. 5.44) whilst Price [88] has studied the ring opening polymerisation of poly(dimethylsiloxane) (Fig. 5.45). Price found that in the presence of ultrasound, and the presence of sulphuric acid at room temperature, faster polymerisation rates and higher molar masses were obtained. 

PTMC synthesis is realised either by copolymerisation of epoxides with carbon dioxide or by the ring-opening polymerisation (ROP) of cyclic carbonate monomers. It is also possible to obtain aliphatic carbonates via polycondensation of dialkyl or diphenyl carbonate or chlorophormates and aliphatic diols. However, polycondensation usually leads to polymers with rather low molar masses (Hyon et al., 1997). Besides, side reactions often occur during polycondensation (Jerome and Lecomte, 2008). 

Table 4.2 Properties of poly(trimethylene carbonate) of different molar masses obtained via ring-opening polymerisation...

Ragaini [86] has reported that the ring opening polymersiation of e-caprolactam (nylon 6, Fig. 5.43), in the presence of ultrasound, takes place without the need for added water and yields larger molar masses in shorter reaction times and at lower reaction temperatures than conventional polymerisation. 

Poly((0-pentadecalactone) (PPDL) is a lactone-based ring-opening polymer with good mechanical and biodegradation properties. Recently, the lipase-catalysed interfacial polymerisation of (O-PDL in an aqueous biphasic medium allowed an increase of the molar mass of oligo (O-PDL to 3,507 g/mol [115]. 

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