Preparation And Properties Of Secondary Grafting Copolymers Of Polyethylene And Reactive Type Dripping Agent

The effects of the preparation of secondary grafting copolymers and their blends on the dripping properties of the films were studied.The secondary grafting copolymers of LLDPE-g-GMSAA were prepared using monoacrylic acid monostearate?GMSAA?and linear low density polyethylene?LLDPE?as main materials by extrusion grafting and secondary grafting,the secondary grafting copolymers of LLDPE-g-GMSAA were extruded with LLDPE and EVA in a certain ratio by a twin-screw extruder to form films.The properties of the films were studied.The results show that the characteristic absorption peak at 1635 cm^-1 disappears and a new characteristic absorption peak appeared at 1730cm^-1 in Fourier transform infrared spectroscopy?FTIR?spectrum of LLDPE-g-GMSAA,which proves that GMSAA has been grafted onto the LLDPE molecular chain.The grafting ratio of the secondary grafting copolymer is 1.74%,which is much higher than the graft ratio of the primary graft.The dripping properties of the secondary grafting copolymers was significantly improved,the acceleration dripping duration is 24 days at 60°C.The surface wetting properties of the films were improved,the light transmittance,haze and mechanical properties were not changed evidently.The secondary grafts of SPANAA and LLDPE were prepared,the GMSAA secondary grafts and the SPANAA secondary grafts were mixed blowing films by different ratio.The effects of dripping agent ratio on the dripping properties of the films were studied.The results showed that the contact angle of the blend films were reduced from 59.36°to 45.64°,compared with film of single dripping agent,the crystallization temperature and melting temperature of blend films were not changed evidently.The light transmittance is about87%,the haze is reduced,and the mechanical properties of the films were not greatly changed.When the ratio of GMSAA secondary grafts to SPANAA secondary grafts is 3:5,the dripping effect is best,the accelerated dripping duration is 19 days at 60°C.The results show that the film dripping time can be improved by the blend of two kinds of droplet agents,and other properties can meet the normal requirements for the use of thin films,which have a certain application value.The dripping agents GMSAA and SPANAA were grafted with the modified nano-SiO₂by grafting technology,respectively.FTIR spectra of nano-SiO2 presented new absorption peaks at 2920 cm^-1,2849 cm^-1,1727 cm^-11 and 1469 cm^-1,which indicating that the dripping agent reacted with nano-SiO2.The dripping agent of the grafted nano-SiO2,LLDPE and EVA were mixed and blown into films according to different ratios.The properties of films were investigated.The results show that the dripping properties of the grafted nano-SiO₂blend films were improved.The acceleration dripping duration is 26 days at 60°C.The contact angle of the blend films also decreases with increasing grafting copolymers,the minimum is 39.39°.The light transmittance of the films is improved and the haze is reduced.The addition of nano-SiO₂ did not affect mechanical and thermal properties.