Preparation Of PFPE-Incorporated Polyurethane Elastomer/Graphene Complex Films And Research Of Antibacterial And Anti-Adhesive Property

Thermoplastic polyurethane(TPU)is an environmentally friendly material with simple synthesis and excellent properties,including high tension,high tensile strength,toughness,and resistance to aging.It is commonly used in medical devices,such as central venous catheters(CVCs)and urinary catheters,as an implantable catheter material.Prolonged implantation in the human body can easily cause bacterial infections,leading to treatment costs exceeding$2 billion annually in the United States alone.Therefore,developing medical catheter materials with long-lasting antibacterial and anti-adhesive properties is of great significance.This thesis first regulates the performance of TPU by adjusting the ratio of soft and hard segments during the TPU synthesis process,producing a series of TPU materials with different properties.Next,the soft segment of TPU is partially replaced with perfluoropolyether alcohol(PFPE-OH)to introduce a fluorine-containing chain segment and improve the antibacterial and anti-adhesion ability of the TPU material.Specifically as follows:Firstly,we using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)triblock copolymer(Pluronic L-81)as the soft segment and 1,4-buta nediol(BDO)as the hard segment and 4,4’-methylenebis(cyclohexyl isocyanate)(HM DI)as condensing agent,by adjusting the ratio of soft and hard segments,synthesizing a series of TPU materials with different mechanical properties:TPU-1,TPU-2,TPU-3,and TPU-4.Their structures are characterized by FT-IR,1H-NMR,and TPU-2 is fo und to have the optimal performance by mechanical testing when the molar ratio of ha rd and soft segments is 8:2.Then,Quaternary ammonium salt-Dodecyldimethylbenzyl ammonium chloride(QAS-1227)is combined with graphene oxide(GO)through pi-pi conjugation to obtain GO-QAS,which is physically blended with TPU material at a c oncentration of 1 wt%.The resulting film material:TPU/GO-QAS,has excellent surfa ce antibacterial properties and can kill more than 99%of 10~6 CFU/m L of Gram-negati ve bacteria(E.coli)and Gram-positive bacteria(S.aureus)after 15 min of contact.Furthermore,because prolonged implantation can cause materials to absorb prote ins and other substances on the surface,leading to bacterial colonization,TPU-F mater ials with different mechanical and hydrophobic properties are obtained by replacing pa rt of the soft segment(L-81)of TPU with PFPE-OH.By adjusting the ratio of PFPE-O H and L-81 we synthesized a series of TPU-F materials TPU-F1,TPU-F2,TPU-F3 wi th different mechanical and hydrophobic properties.Their composition is determined b y FT-IR,1H-NMR,and other tests,and their surface hydrophobic properties are deter mined by water contact angle measurements,with the highest contact angle data reach ing 113°.GO-QAS is then physically blended with TPU-F materials in the same way t o obtain TPU-F/GO-QAS materials with surface antibacterial and anti-adhesive proper ties.Antibacterial tests show that this material has similar antibacterial performance to TPU/GO-QAS film,with more than 99%of 10~6 CFU/m L of E.coli and S.aureus bein g killed after 10 min of contact.Long-lasting anti-adhesion tests show that this materia l can maintain a anti-bacterial and anti-adhesion rate of over 85%for E.coli and S.au reus at a concentration of 10~8 CFU/m L for 4 days.