Viscosification properties of poly(butylene succinate)by melt polycondensation
In order to solve the problem of degradation and aging of biodegradable poly(butylene succinate)(PBS)during long-term normal storage,the molecular weight of PBS was improved by melt polycondensation.The viscosity,molecular weight,thermal properties and rheological properties of PBS were studied under various reaction temperatures,reaction time,initial viscosity and melt film thickness.The results showed that the molecular weight of PBS increased with the increasing of melt polycondensation temperatures.The intrinsic viscosity of PBS increased from 1.049dL/g to 2.072dL/g at 220℃ within 60min.The PBS sample possessed lower initial viscosity value indicated faster viscosity increasing rates.The thickness of PBS melt was inversely proportional to its viscosity increasing reaction rate.It was shown that the elevated viscosity values also led to a decrease of crystallization properties and melting point of PBS.The rheological test results showed that with the increase of viscosity,the melt strength and thermal stability of PBS increased,which can meet the needs of reprocessing and use.The melt re-polycondensation process can effectively solve the degradation problems of PBS being unable to meet its subsequent processing and using requirements.
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