Research On Synthesis Of Polyurethane And Its Composites With Chitosan

The PU solution was synthesized by prepolymerization-chain extension-neutralization-dispersion method. The PU microsphere was prepared by coacervation phase separation method. The influencing factors of PU solution were investigated in order to find the best synthesized conditons which included prepolymerization temperature, prepolymerization time and stiring up rate etc.The anionic PU solution was synthesized by prepolymerization-chain extension-neutralization-dispersion method with toluene diisocyanate, polycaprolactone, polyethylene glycol, dimethylolpropionic acid and triethylamine.The results showed that the optimum reaction conditions were as follows:the volume of water wasl4mL; the prepolymer temperature was70℃; the prepolymerization was2.5h; Chain extendering time was3h. The PU solution was colorless and transparent. The content of-NCO was determined by titration method. The clouding point of PU aqueous solution increased with PEG molecular weight increasing.PU/CS was a new composite material microsphere which was prepared by the coacervation phase separation method. The results showed that the mole ratio of IPDI and PEG was3:1; the mole ratio of PCL and PEG was35-40%; the prepolymer temperature was70℃; the concentrations of Polyurethane aqueous solution was35-40%; the prepolymer time was2.5h; the chain extendering was3h; the concentrations of CaCl2was more than8%; the emulsifying rate was500r/min.FTIR analysis showed the-NCO was reacted completly, forming urethane. SEM results showed the average diameter of the PU/CS composite microspheres was about2-3mm and the distribution of spherical PU/CS composite microsphere was relatively uniform, which was good for drug release. The PU microsphere was easy dissolve in alkaline solution.The drug-carried PU/CS composite microsphere was prepared by coacervation phase separation method with Tetracycline Hydrochloride (TH) as drug models. The enbedding ratio and drug loading of PU/CS composite microsphere increased with the PEG molecular weight increasing between200and800.The PCL affected the strength of microsphere.The hemolysis rate of PU/CS composite microsphere was2.0~3.1%; the consuming rate of blood platelet was less than40%, which accorded with the standards of biomaterial of China.The results showed that PU/CS composite microsphere had good blood compatibility.The PU/CS composite microsphere was expected to have a further application as drug delivery carrier material.