Study on the Microwave Assisted Surface-modification of Polyurethane and Its Blood Compatibility
|Keywords||Microwave Polyurethane Poly(ethylene glycol) Grafting reaction Heparin Blood compatibility|
In order to improve the blood compatibility of polyurethane, this work mainlystudied on the utility of microwave irradiation assisted surface grafting modificationmethod. The polyurethane surface were firstly activated by4,4’-Methylenebis(phenylisocyanate) via microwave irradiation and then grafted with polyethylene glycol(PEG/MPEG/APEG) in different molecular weight of as well as heparin. ATR-FTIR,surface water contact angle, SEM and AFM were used to analyse the surfacecharacteristic. Hemolysis ratio, the whole blood clotting time, prothrombin time andthe complement activation were used to inspected the blood compatibility.The polyurethane membrane surfaces were activated by microwave irradiationassisted technology. The results showed that: microwave irradiation assisted reactionscould significantly accelerate the rate of activation of polyurethane surface. Thegrafting results were affected by the microwave power, reaction time, as well as thevolume of the reactant mass fraction. Under our experimental conditions, when themicrowave power was100W, the mass fraction of the reactants was5%with10minutes reaction time, the effect of microwave-assisted surface activation took thebest benefits. SEM surface analysis showed that, compared with conventional heatedreaction method, the extent of damage to the membrane surface was smaller viamicrowave irradiation assisted reactions.To graft PEG/MPEG with different molecular weight onto polyurethanemembrane surface via microwave irradiation assisted technology and compare withconventional heated method of grafting PEG/MPEG. ATR-FTIR, surface watercontact angle analysis were used to inspect the effect of different modificationmethods on the polyurethane surface properties. SEM, AFM were used to inspect theeffect of different modification methods on the polyurethane surface topography. Thehemolysis ratio, platelet adhesion test, clotting time, as well as complement activationtest were used to inspect the effect of different modification methods and the chainlength of polyethylene glycol on the blood compatibility of polyurethane surface. Theresults indicated that: microwave irradiation assisted reactions could significantlyaccelerate the speed of the PEG/MPEG grafted onto polyurethane surface, but notmuch impact on the graft yield. SEM and AFM surface analysis showed thatcompared with conventional heated reaction method, the extent of the damage to themembrane surface was smaller, the membrane surface was smoother via microwave irradiation assisted reaction. The water contact angle results also showed that themicrowave irradiation assisted reaction of grafting PEG/MPEG obtained the surfaceswith good hydrophilic properties. Blood compatibility related tests confirmed that thepolyurethane surface using microwave irradiation assisted modification were moreexcellent in blood compatibility.After polyurethane surface activation like the first step, the diamino-terminatedpoly (ethylene glycol) was grafted onto the polyurethane using microwave irradiationassisted technology. Finally the heparin was activated with the EDC HCl and NHSand grafted onto the polyurethane surface. Change of the performance and theimprovement of blood compatibility of heparinized polyurethane surface to study theinfluence of heparin on polyurethane surface properties. Blood compatibility testresults confirmed the significant improvement in heparin material blood compatibility.