Study On Polyolefin Adhesive Resin Material

This paper aims to study polyethylene(PE) grafted with maleic anhydride(MAH) through the melt grafting method to prepare adhesive resin. There were five aspects studied, including processing temperature, selection of experimental base resin, effect of initiator concentration, effect of monomer concentration and selection of additives to reduce the crosslinking reaction so that good adhesion resin can be achieved when bonded with nylon6(PA6) film and have the minimum cross-linked point. The main properties of samples were studied, including the grafting rate and gel content of grafted copolymer, the peel strength, tensile property, melt flow rate, rheological properties, thermal properties, water vapor transmission rate, crystallization property and so on.A variety of polyolefin resins were tried to confirm the best one, including low density polyethylene(LDPE), very low density polyethylene(VLDPE), linear low density polyethylene(LLDPE), and the compound of different resins with different amount. The result showed that when VLDPE/LLDPE=90/10, the properties of system were the best. The best processing temperature was studied and 170℃ was the best temperature. Chemical titration and infrared spectrum analysis showed that the MAH monomer was grafted onto PE molecular chain successfully.Benzoyl peroxide(BPO) was chosen to be the initiator and effect of different content of BPO on the system was studied. The result showed that with the increase of BPO content, the grafting degree increased at first and then decreased. When the BPO content was 0.08phr, the properties of system were the best. The effect of different content of MAH on system was also studied. The result showed that with the increase of MAH content, the grafting degree increased at first and then decreased in a small range. When the MAH content was 0.8phr, the properties of system were the best.Due to the inevitable crosslinking reaction, gel phenomenon would be appear and there would be cross-linked points when blowed into the film, so affected the preparation of adhesive resin bounded with PA6 film. Thus, different kinds of additives were tried to reduce the crosslinking phenomenon, including dimethyl formamide (DMF) and styrene (St), indicating that St was much better.The conclusion of the study showed as following:170℃ was the best processing temperature. When the system base resin was VLDPE/LLDPE=90/10, the properties of system were the best. The best MAH content was 0.8phr, the best content of BPO was 0.08phr, and the content of St was 0.8phr. Under the condition, the system grafting rate reached 1.78%, the gel content was 4.3%, the peel strength with PA6 film reached 65.9N/cm, basically meeting the requirements of practical application.