Preparation and Characterizations of Polyglycolic Acid Film Materials
To solve the compatibility between the biodegradable raw materials of films and bags,and the full biodegradability of the final products,under the synergistic effects of chain extender(KL-E4370)and antioxidant(1010),different ratios of polyglycolic acid(LPGA)with a low melting point and poly(butyleneadipate-co-terephthalate)(PBAT)were reacted and co-extruded by melt blending,and the blend was blown into shape.At the same time,the thermal properties,scanning electron microscopy,and mechanical properties of LPGA/PBAT blend were analyzed,and the degradation and barrier properties of the films prepared from the blend were analyzed.The results show that when LPGA is used as the main phase,the addition of chain extenders could achieve compatibility between LPGA and PBAT at the interface using scanning electron microscopy.When PBAT is used as the main phase,through observing the changes in the crystallization temperature,melting point,and blend interfaces revealed by scanning electron microscope,it is found that a large amount of PBAT chains preferentially form cross-linked structures under the actions of chain extenders,which affects the crystallization performances of the blend and weakens the compatibilization effect of the chain extender.When the content of LPGA is above 70 phr,the longitudinal tensile strength of the film is greater than 29 MPa,the longitudinal elongation at break is greater than 368%,the transverse tensile strength is greater than 24 MPa,the transverse elongation at break is greater than 200%.The mechanical properties of this film are similar to these of films on the market,which could meet the applications of downstream markets.The comprehensive barrier performances of LPGA/PBAT film are excellent,the water vapor permeability coefficient is less than 2.90×10-14 g·cm/(cm2·s·Pa),and the oxygen permeability coefficient is less than or equal to 0.05×10-14 cm3·cm/(cm2·s·Pa).The biodegradation rate of the LPGA/PBAT film with a mass ratio of 70/30 after 175 d is greater than90%,which could meet the criteria of home composting.
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