Preparation and properties of PEG-CL-LA copolymer for polyurethane bandage
Using stannous octoate as the catalyst,polyethylene glycol(PEG)as the starting agent,ε-caprolactone(CL)and lactic acid(LA)as raw materials,the binary alcohol copolymers(PLCA)with different quantities of CL unit and LA unit were directly condensed and synthesized under the condition of 170℃ and high vacuum.PLCA was mixed with an excess of 4,4'-diphenylmethane diisocyanate(MDI-100)and a small amount of tertiary amine catalyst,reacted at 70℃ to obtain a copolymer mixed colloid(PLCA-PU)with isocyanate end terminated,which was then coated on polyester porous woven belt to prepare polyurethane bandage.By maintaining the amount of PEG,changing the ratio of CL and LA and the amount of isocyanate,a series of PLCA and PLCA-PU were obtained.Their structures were analyzed,and the curing time and radial compressive force of polyurethane bandage were tested.The research results showed that PLCA and PLCA-PU had been successfully prepared.When R=5,and n(PEG)∶n(CL)∶n(LA)=1∶6∶7,the curing time of the bandage prepared by PLCA-PU was 383 s,the maximum compressive force could reach 19.4 N.Choosing the appropriate material ratio could meet the requirements of rapid curing and having appropriate rigidity and strength of bandage.
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