Performance Characterization Of Different Vegetable Protein Adhesives And Application In Apple Fresh-keeping Corrugated Boxes

With the rise of oil prices and the improvement of people’s awareness of environmental protection,green and pollution-free biomass adhesives（plant protein,lignin,etc.）have gradually become the focus of attention.However,due to the poor water resistance and low bonding strength of traditional plant protein and other biomass adhesives.In fact application is limited.In this research,green soybean meal-based protein-based adhesives（SMA）and high-temperature peanut meal-based protein-based adhesives（SMA）and high-temperature peanut meal-based protein-based adhesives（SMA）and high-temperature peanut meal-based Adhesives（HPMA）,cottonseed meal-based protein-based adhesives（CMA）,and analyze and characterize the physical and chemical properties and structure of SMA,HPMA,and CMA adhesives during the modified cross-linking process.And use it to prepare fresh-keeping corrugated boxes for fruits and vegetables,and explore the fresh-keeping effect of the fresh-keeping corrugated boxes in apples by measuring various physical and chemical index parameters of the apples during the storage period.The specific conclusions are as follows:（1）Use sodium dodecyl sulfate（SDS）,nano silica（n Si O₂）and polyamide epichlorohydrin（PAE）resin to modify and cross-link to prepare SMA,HPMA,CMA adhesives,SDS addition amount 3.2%,n Si O₂ The addition amount is 2%,the PAE addition amount is 85%,and the modification time is 30 minutes.Under these conditions,the boiling water bonding strengths are 1.07±0.03 MPa,0.98±0.03 MPa,1.07±0.03 MPa,which met the national class I standard of poplar plywood（GB/T 9846-2015）.（2）The structure of HPM adhesive was characterized by FTIR and SEM.The results showed that SDS destroyed the secondary and tertiary structures of peanut protein,exposed a large number of hydrophobic groups in order to improve the water resistance of the HPM adhesive;On this basis,added n Si O₂,hydrolysis in solvent and condensation reaction,it would form a low surface energy,and form a nano scale rough surface on the surface of the substrate to enhance the hydrophobicity;At the same time,it could be combined and filled in the pores of the wood surface where the protein does not act on,so as to improve the shear strength.At last,PAE was added for crosslinking.The nitrogen heterocyclic butane PAE could react with various active groups of peanut protein,such as carboxyl group,amino group,to form a three-dimensional network structure,which could significantly improve the water resistance and shear strength of HPM adhesive.（3）The weight loss rate,hardness,soluble solids and Vc content of apples during the storage period of four different corrugated boxes were measured.Through data analysis,it can be concluded that the fresh-keeping effect of soybean,peanut and cottonseed protein adhesive bonded corrugated fresh-keeping paper boxes is greater than that of ordinary corrugated paper boxes.Freshness preservation effect.This is because the n Si O₂ particles are evenly embedded in the gaps of the gelled network formed,which improves the moisture barrier performance of the packaging box.On the other hand,the n Si O₂ particles also have antibacterial effects,thereby inhibiting the entry and reproduction of microorganisms.The softening phenomenon of the apple.At the same time,the physiological function of the apple is inhibited,and the TSS content and Vc content of the apple are better maintained,so as to achieve the preservation effect.