Preparation And Properties Of Antistatic Polyethylene Resin

In this thesis,a kind of cationic quaternary ammonium salt N,N’,N’’-（（2-hydroxybenzene-1,3,5-triyl）tris（methylene））tris（4-chloro-2-hydroxy-N,N-dimethylbutan-1-aminium）（EDP）was prepared by the reaction of 2,4,6-tris（Dimethylaminomethyl）phenol with epichlorohydrin.A kind of cationic quaternary ammonium salt N,N’,N’’-（（2-phenylmethacrylate-1,3,5-triyl）tris（methylene））tris（4-chloro-2-hydroxy-n,n-dimethylbutane-1-amine）（AEDP）containing double bond were prepared by 2,4,6-tris（Dimethylaminomethyl）phenol weas modified by acrylic acid.The structures of EDP and AEDP were analyzed by Fourier transform infrared spectroscopy（FT-IR）and nuclear magnetic resonance spectrum（H-NMR）.The results of thermogravimetric analysis（TGA）showed that both the EDP and AEDP had good thermal stability.LLDPE/EDP with different content EDP was prepared with low-density polyethylene（LLDPE）and EDP by Internal mixer.LLDPE-g-AEDP was prepared by grafting of Antistatic agent onto molecular chain of pre-irradiated LLDPE.The films of LLDPE/EDP and LLDPE-g-AEDP were prepared by a vulcanizing machine and their thermal properties and mechanical properties were tested by differential scanning calorimetry（DSC）and material testing machine.The results show that the melt temperature and crystallization temperature of LLDPE film were not affected by adding EDP or AEDP.After adding the EDP and AEDP,the regularity of polyethylene molecular chain was destroyed,which led to the decreasing of tensile strength,elongation at break and rectangular tearing property of the LLDPE films.However,adding EDP and AEDP did not affect the processability of polyethylene.Hydrophilicity,dustproof and antistatic properties of the LLDPE/EDP and LLDPE-g-AEDP films were increased with the addition of EDP and AEDP.The results of film contact angle of films was about 70 ^o which was 30 ^olower than that of pure LLDPE film.Compared with the pure LLDPE film,the volume resistivity of antistatic films decreased to 4.39×10⁸Ω·m,and the surface resistivity decreased to 1.75×10¹¹Ω.The diffusion coefficients of LLDPE/EDP films with different thickness soaked in anhydrous ethanol at 60 ^oC for 0-6 hours were calculated by FT-IR and Fick’s second low fitting formula.The results shows that the diffusion coefficient of EDP decreases with the increasing of the film thickness.The thicker the film is,the stronger the interaction between the EDP and LLDPE molecules inside the film,the slower the diffusion rate of EDP to the film surface,and the longer the time of the films with antistatic property.The infrared spectra of LLDPE/AAF/EDP films with different immersion time were measured.Combined with Fick’s second law fitting formula,the migration rates of small molecules inside LLDPE were calculated.With the increasement of the thickness of the film,the migration rate of AAF and EDP were slow down.The addition of AAF could increase the compatibility of EDP with LLDPE and slow down the migration rate of EDP in LLDPE/AAF/EDP.After adding AAF the migration rate of 0.17 mm LLDPE/AAF/EDP film is 8.01105×10^-10cm²/min,which was one order of magnitude lower than that of 0.17 mm LLDPE/EDP film.The contact Angle,volume resistivity and surface resistivity of LLDPE/AAF/EDP films with different EDP contents were measured.The results showed that the contact angle of LLDPE/AAF/EDP（0.1 wt%AAF,1.5 wt%EDP）film was 71.1^o,which was 30^olower than that of pure LLDPE films.The volume resistivity and surface resistivity of LLDPE/AAF/EDP（0.1 wt%AAF,1.5 wt%EDP）film were 3.85 x 10⁹Ω·m and 2.85×10¹¹Ω.Addition of AAF can increase the hydrophilicity of the film and delay the precipitation rate of molecules under the quaternary ammonium salt,so that the surface of the films is easier to form a water film to enhance the electrical conductivity of the linear low density polyethylene film and prolong the antistatic film.