Poly(1

2-cyclohexylene carbonate) (PCHC) was prepared by copolymerization of carbon dioxide and cyclohexene oxide with Y(CCl3COO)3-ZnEt2-glycerin rare earth metal coordination ternary catalyst.The result polymer showed number average molecular weight (Mn) of 56.3103 with polydispersity index of 4.9. Though PCHC showed high glass transition temperature (Tg)

PCHC was easy to degrade during melt processing

accompanied by severe deterioration of its mechanical performance

which constituted one of the main obstacles for commercialization of PCHC.In order to impove the thermal stability and mechanical properties of PCHC

the thermal decomposition reaction was compensated by the chemical chain extension reaction.At first

maleic anhydride was used as end-capper of PCHC to prevent its chain unzipping reaction

the MA and PCHC in weight ratio of 1 ∶100 were added into dichloromethane to make a 20 wt% solution

and refluxed at 41~43℃ for 48 h

then the polymer was precipitated by ethanol to obtain maleic anhydride end-capped PCHC (MA-PCHC).MA-PCHC was then subjected to chain extension reaction at 180℃ and 60 r/min in the a Haake mixer for 5 min using 2

2'-bis(2-oxazoline)(BOZ) as chain extender.The optimal chain extension condition was found when equimolar BOZ and carboxyl group in MA-PCHC were used

the Mn of MA-PCHC increased from 5.6104 to 12.4104.The thermal stability of PCHC after chain extension was greatly improved

compared with the as-polymerized PCHC

the thermal decomposition temperature at 5 wt% loss (Td-5%) for chain extended PCHC increased from 260℃ to 317℃

the Tg increased from 114℃ to 133℃

and most importantly

the melt viscosity increased by 30 times.It should be noted that no significant change in gelatin content was observed during chain extension reaction.Moreover

the chain extended PCHC showed tensile strength increase from 35.8 MPa (as polymerized PCHC) to 40.2 MPa

and the elongation at break increased from 4.59% to 6.22%

yielding phenomenon was observed in the stress-strain curve.Therefore

the chain extension strategy was effective to improve the mechanical performance of PCHC.