Preparation Of Amphiphilic Starch And Its Application In Antiliacterial Plastic Film And Wound Dressing

Starch(ST)is a polyhydroxyl natural polymer.It has a wide range of sources,low prices,good natural degradability and biocompatibility.It has great advantages in the field of bio-food and biomedicine.However,raw starch is often not directly applicable to many fields because of insufficient hydrophilicity,poor water resistance,easy aging and high brittleness.In order to improve its performance and expand the scope of application,the paper used the modified starch in the application research of antibacterial plastic wrap and wound dressing film.The following was the main research content and research results of this article:(1)The starch was extracted from the potato by physical method,and then etherified into sodium carboxymethyl starch to form a cold water-soluble starch.It underwent esterification reaction with lauric acid to form an amphiphilic starch under the action of Novozym which was external hydrophilicity and internal lipophilicity.By using Fourier transform infrared spectrometer(FTIR),scanning electron microscope(SEM),X-ray diffractometer(XRD),X-ray photoelectron spectrometer(XPS),showed that carboxymethyl starch sodium laurate starch ester(CMS-LS)had successfully prepared.The surface of the modified starch had a pore-like rough particle structure and the crystalline area was reduced.Through surface tension,contact angle,emulsification and cytotoxicity tests,it was found that CMS-LS has low surface tension,good emulsification and excellent biocompatibility.(2)Encapsulating the anti-bacterial cinnamon essential oil(CO)with CMS-LS to form CMS-LS-CO,blent it with sodium alginate(SA)as the middle layer.At the same time the multiple layers antibacterial freshness film CS/SCO/CS was prepared with chitosan as outer layer.By using FTIR,SEM,XRD to characterize the properties of the film,there was a hydrogen bond between the molecules and the membrane was well.The tests on the mechanical properties,light transmittance and antibacterial properties of the film showed that when the amount of CMS-LS-CO was 0.5%,the tensile strength was 22.09±1.16 MPa,the elongation at break was 24.84±1.67%,the light transmittance was 86.9%,and the inhibition rates of E.coli and S.aureus were 61%and65.9%,respectively,which had a good preservation effect on fruits,at the same time the soil degradability rate could reach 70%within 28 days.(3)Encapsulating CO and hydrocotyle oil(HO)of healing effect with CMS-LS,blent it with polyvinyl alcohol(PVA)and SA to prepare polyvinyl alcohol/sodium alginate with antibacterial and healing effect dressing film(PSCCH).Using FTIR,SEM and XRD to analyze the performance of PSCCH thin film,the results showed that PVA and SA molecules had hydrogen bonding effect,the film surface was rough and had many pores.Through testing the mechanical properties,light transmittance,water vapor transmission rate,swelling rate,water solubility and water content of the film,it was found that when PVA:SA was 8:2,the tensile strength of PSCCH was 18.44±1.44 MPa,the elongation at break was 97.92±5.71%,the light transmittance was 73%,and the water vapor transmission coefficient was 791 g/(m~2?d),the swelling rate could reach 180%,the water solubility was 68%,the water content was 19%.When the essential oil ratio CO:HO was 1:2,the antibacterial performance and cytotoxicity were tested,and it was found that the cell proliferation could reach141%while maintaining 43.3%and 47.7%of inhibition rates on E.coli and S.aureus,respectively.