Preparation Of PE-g-MAH Adhesive And Its Application Study In Barrier Film

Multilayer co-extruded film is an important material widely used in various industries such as medicine,packaging,food,etc.It consists of three functional layers barrier layer,adhesive layer and support layer.It has excellent barrier,mechanical and tensile properties.No other compounding methods are required in the production process,which is a relatively green and inexpensive food packaging technology.The support layer is generally composed of a non-polar polymer polyolefin,which can be bonded to the adhesive layer by thermal reaction,while the barrier layer is generally composed of a polar polymer that cannot be directly bonded to the adhesive layer,so the choice of the adhesive layer is crucial,and it needs to have good amphiphilicity to bond the barrier layer and the support layer tightly together.In this paper,PE-g-MAH adhesive is prepared by melt grafting method and used as an adhesive when the barrier layer is EVOH and PA,and the optimum grafting rate of the adhesive and its process conditions are explored.The main findings of the study are as follows.In the experiment of preparing PE-g-MAH,PE-g-MAH was prepared by melt extrusion method,and the graft was characterized by infrared spectroscopy and DSC,and the type of initiator,the content of initiator,and the grafted monomer were discussed.The content of MAH affects the grafting rate,the number of crystal points and the melt index of PE-g-MAH adhesive.The results showed that the initiation effect was the best when the initiator was DCP.When the initiator is DCP,and with the addition of the initiator content and MAH content,the grafting rate of PE-g-MAH first increases and then decreases,and the melt index of the grafts all show a downward trend.The fluidity of the body is weakened,and the number of crystal points increases first and then decreases.In the experiments in this chapter,considering factors such as grafting efficiency,when the initiator is DCP content of0.05%and MAH content of 1%,the highest grafting rate is 0.68%,the melt index is0.94 g·（10 min）^-1,and the number of crystal points is 12.When the barrier layer is made of EVOH material,through the 180°peel strength test,PE-g-MAH with different grafting ratios is used to conduct hot-pressed peeling experiments,and the grafting ratio,melt index,number of crystal points,and adhesion are discussed.The effects of agent content,hot-pressing temperature,and hot-pressing pressure on the peeling strength were measured by a universal experimental tensile machine,and the surface appearance of the peeled sample was characterized.The results show that when the binder is PE-g-MAH,the peel strength of PE-g-MAH/EVOH samples increases first and then decreases with the increase of grafting ratio,and when the grafting ratio of PE-g-MAH When the branch rate is0.63%,the melt index is 1.02 g·（10 min）^-1,the effect is the best;the less the number of crystal points on the surface of PE-g-MAH after blown film,the better the peel strength is.Adhesiveness;when using a bonding resin with a grafting rate of 0.63%to bond EVOH,the more bonding resin is added to the matrix resin PE,the better the two-phase bonding;with the hot pressing temperature and With the increase of hot pressing pressure,the peel strength first increased and then decreased;SEM test results showed that the grafting rate of PE-g-MAH was 0.63%,and the melt index was 1.02 g·（10 min）^-1.When the temperature is 210℃and the hot pressing pressure is 1 Mpa,the maximum peel strength is 69.7 N/cm,the surface roughness of the sample at the microscopic level is the largest,and the bonding property of the adhesive is the best.When the barrier layer is made of PA material,through the 180°peel strength test,PE-g-MAH with different grafting ratios is used to conduct hot-pressing peeling experiments,and the grafting ratio,adhesive content,hot-pressing temperature,and hot-pressing temperature are discussed.The impact of the compressive force on the peel strength was measured by a universal test tensile machine,and the surface appearance of the peeled sample was characterized.The results show that when the binder is PE-g-MAH,the peel strength of PE-g-MAH/PA samples increases first and then decreases with the increase of grafting ratio,and when the grafting ratio of PE-g-MAH When the branching rate is 0.35%,melting means that when the bonding resin with a grafting rate of 0.35%is used to bond PA,the more bonding resin is added to the matrix resin PE,the better the two-phase adhesion is;With the increase of hot-pressing temperature and hot-pressing pressure,the peel strength first increases and then decreases;SEM test results show that the grafting rate of PE-g-MAH is0.35%,and the hot-pressing temperature is 230℃.When the pressure is 0.5 Mpa,the peel strength is the largest,the surface roughness of the sample at the microscopic level is 78.5 N/cm,and the adhesion of the adhesive is the best.