Preparation And Performance Of Silicone-modified Polyurethane With Pendent Quaternary Ammonium Salts

With polydimethylsiloxane (PDMS) as soft segment polyurethane (PU) block copolymers by the introduction of low surface energy siloxane structural units, giving a copolymer of low surface energy properties, while polyurethane structural unit also gives excellent mechanical properties of copolymer and surface adhesion. Quaternary ammonium salts (QAS) have been known and widely used for more than half a century to control microbial growth. Silicone-modified polyurethane with pendent quaternary ammonium salts can be a good coating polymer which possesses bactericidal, low surface energy and good mechanical properties, so it has been widely used in the marine anti-fouling, medical implants, clothing, toilet, catheters and contact lenses, etc, and it has become one of the most active research areas.First of all,1,3-bis(glycidoxypropyl)tetramethyldisiloxane was synthesized via hydrosilylation using allyl glycidyl ether and1,1,3,3-tetramethyldisiloxane, and then1,3-bis(3-(1-methoxy-2-hydroxypropoxy)propy l)tetramethy ldisiloxane was synthesized via alcoholysis and the structure were characterized by FT-IR and1H NMR. After2,4,6-tri(3-chloropropyl)-2,4,6-trimethylcyclotrisiloxane was abtained via hydrolysis, polysiloxanes with chloropropyl are prepared by ring-opening copolymerization, trifluoromethane sulfonic acid as the catalyst, and then the molecular weights of reaction products was measured by GPC and functional group analysis. Then the bactericidal QAS groups are introduced to polysiloxane chain via quaterisation. Finally, polyurethanes are prepared by the reaction between hydroxyl groups and isocyanate, and the surface property and bactericidal performance of polyurethanes are also tested.The results indicated that1,3-bis(3-(1-methoxy-2-hydroxypropoxy)propyl)-tetramethyldisiloxane was abtained via hydrosilylation and alcoholysis with a yield of63.8%. The ring-opening copolymerization between2,4,6-tri(3-chloropropyl)-2,4,6-trimethylcyclotrisiloxane and octamethyl cyclotetrasiloxane was reacted for24h at70℃. And the hydroxy-terminated poly[(3-chloropropyl)methylsiloxane]-ran-polydimethylsiloxanes with different molecular weights(3000g/mol,5000g/mol, 8000g/mol) and different contents of chloropropyl(0%,10%,20%,30%) were collected. By cationic titration, the reaction conversion of quaternize reaction could reach95%after14h. The polyurethane material with not only has the low surface energy, but also has more than90%antibacterial to gram-type positive and gram-negative bacteria. Especially, the material with20%content of QAS had the good performance both in sterilizing rate and hydrophobic nature.