Study On Biodegradable Food Packaging Film Based On Eggshell Powder

In recent years,the environmental pollution caused by single-use plastics deviates from the current environmental protection policies and the vision of "carbon neutrality",and "environmentally friendly" biodegradable materials have become a good substitute for traditional plastics.Among them,polybutylene adipate/terephthalate(PBAT)has attracted much attention due to its excellent biodegradability and good ductility,but its poor rigidity and high price limit its application in Application and development in the market.At the same time,eggshell,as an important processing by-product of poultry eggs,can be used as a biological filler for PBAT.Grinding it into eggshell powder(ESP)as a natural filler and melt blending with PBAT not only improves the properties of the composite material,but also provides a new idea for promoting the efficient utilization of eggshell resources.However,the poor interfacial compatibility of ESP with PBAT limits the amount of ESP added in the composites.The modification of ESP with aluminate coupling agent(ACA)can effectively improve the interfacial compatibility with PBAT and improve the comprehensive properties of the composite.In this study,ACA was used to hydrophobically modify ESP,and the modified ESP was filled with PBAT to prepare a biodegradable food packaging film;the structure and properties of the modified ESP were studied,and the compounding process was optimized to ensure that the performance of the composite material was improved.At the same time,reduce the cost of eggshell powder-based biodegradable food packaging films;explore the effect of plasticizer epoxidized soybean oil(ESO)on the performance of ESP/PBAT composite films,and develop a high proportion of eggshell powder-based biodegradable films for applications.Food packaging film provides theoretical basis and practical reference.The main research contents and results are as follows:1.The effect of ACA addition on ESP modification and the structure and properties of ESP/PBAT composites was studied.The results show that the addition of ACA reduces the surface polarity of ESP,and a modified ESP with high contact angle,low oil absorption value and sedimentation volume is prepared,and its infrared spectrum shows ACA(2850 cm-1 and 2920 cm-1).The stretching vibration peak of the ESP and the surface of the ESP confirmed the coupling effect of ACA and the surface of the ESP;XRD analysis showed that the addition of ACA did not change the internal crystal form of the ESP;the modified ESP and PBAT were melt-blended to prepare a composite film for structure and performance testing,among which SEM It shows that the modified ESP is embedded in the PBAT molecule,and the addition of ACA significantly improves the interfacial compatibility;when the addition of ACA is 2%,the performance of the prepared ESP/PBAT composite film is the best: the water absorption rate increases from1.62% When it decreased to 1.19%,the elongation at break and tensile strength increased from 207.17% and 6.1 MPa to 378.51% and 12.28 MPa,respectively;at the same time,the color difference analysis showed that the addition of ACA had little effect on the whiteness of the product.2.The influence of modified ESP on the structure and properties of ESP/PBAT composites was explored,and the compounding ratio of the blend system was optimized.The results show that there are no new vibration peaks in the infrared spectrum of the ESP/PBAT composite,and the long groups on the surface of the modified ESP are physically entangled with PBAT;XRD analysis shows that the addition of ESP changes the crystallinity of the system.Lattice constant;SEM shows that when the ratio of the composite film is PBAT/ESP(300/150),the internal bonding of the composite material is tight,and the two have good compatibility.At this time,the mechanical properties and waterproof performance of the film were also significantly improved: the elongation at break was 489%,the tensile strength was 14.5 MPa,and the water absorption was 1.18%;the whiteness and brightness of the film gradually increased with the addition of modified ESP.It becomes smaller,but the color change is acceptable;the addition of modified ESP improves the degradation performance of ESP/PBAT composite film in pH 13 sodium hydroxide aqueous solution;the addition of modified ESP in the system also improves the The storage modulus and complex viscosity of composite materials are beneficial to industrial extrusion granulation.3.The effect of plasticizer ESO on the properties of ESP/PBAT composite films was explored.The results show that when the mass fraction of ESO is 2%,the film has the best waterproof performance and mechanical properties.At this time,the water absorption rate of the film decreases from 1.2% to 1.134%,which significantly improves the tensile strength while ensuring that the tensile strength does not decrease.The toughness of the film and the elongation at break increased from 478% to 643%;at the same time,the addition of ESO improved the degradation performance of the composite film in pH 13 sodium hydroxide aqueous solution;the addition of ESO increased the ESP/PBAT composite film.Thermal stability,improved thermal deformation properties of the film.