A novel poly(phospho-isosorbide) ester (PPI) with series of molecular weight was synthesized from isosorbide and phenyl phosphonic acyl chloride by bulk polymerization and solution polymerization.The structures and molecular weights of PPI were characterized by Flourier transform infrared spectroscopy (FTIR)

nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC).The degradation and swelling experiments of the polymer in aqueous solutions and enzyme solutions showed that it had good biodegradation properties and swelling properties when Mw was below 5104.The degradation rate of PPI was 80%

and swelling rate of PPI was 150% after 25 days.However the degradation and swelling rate decreased obviously when Mw was over 5104.The degradation rate and swelling rate of PPI were only 25% and 40%

respectively.It showed that PPI had high glass transition temperature (Tg)

which increased significantly with the increasing of its molecular weight.For example

the glass transition temperature (Tg) reached to 176 ℃ when Mw was 6104.The influence of molecular weight on the thermal stability indicated that higher molecular weight was beneficial for improving thermal decomposition temperature of the PPI.The initial decomposition temperature (T5%) of PPI increased from 260 ℃ to 315 ℃

while the Mw was raised from 2104 to 6104.