Preparation And Properties Of Polyethylene/Amide Type Dripping Agent Materials

In this thesis,the amide type dripping agent containing double bond were prepared,polyethylene/amide type dripping agent materials were prepared by grafting the amide type dripping agent onto the linear low-density polyethylene chain and the inorganic nano-particles respectively,the properties of the materials were characterized.A kind of reactive dipping agent containing α double bond,lauric acid diethanolamide monoacrylate,was prepared by the reaction of lauric acid diethanolamide(LDEA)with acrylic acid(AA).LLDPE-g-AAL was prepared by grafting of dipping agent AAL onto molecular chain of pre-irradiated low-density polyethylene(ir-LLDPE)by pre-irradiation and reactive extrusion.LDHs-g-AAL were prepared by grafting dripping agent AAL onto the surface of layered double hydroxide(LDHs)modified by silane,and then LLDPE/LDHs-g-AAL were prepared with ir-LLDPE and LDHs-g-AAL by extrusion.The structures of AAL,LLDPE-g-AAL and LDHs-g-AAL were characterized by infrared spectra.The results of thermogravimetric analysis(TGA)showed that both the dripping agent AAL and LDH-g-AAL had good thermal stability.At 190 oC,the loss of weight of AAL is less than 5.8% and that of LDHs-g-AAL is less than 5.0%,which meets the processing and production requirements.The results of SEM showed that LDHs-g-AAL was uniformly dispersed in polyethylene,and there was no large-scale agglomeration.The results of rheological showed that the dripping agent AAL played the role of lubricant,and the addition of AAL and LDHs-g-AAL did not affect the processability of polyethylene.Extrusion blowing of LLDPE-g-AAL and LLDPE/LDHs-g-AAL films was carried out by blowing machine.The thermal properties,mechanical properties,transmittance and haze of the films were studied by means of differential scanning calorimetry(DSC),material testing machine and optical hazemeter.The results showed that the melt temperature,crystallization temperature and mechanical properties of LLDPE film were not affected by the AAL and LDHs-g-AAL.The light transmittance and haze of the films decreased slightly,but the degree of decrease was not obvious.The test results of film contact angle showed that LLDPE film had excellent surface wettability by AAL,and the contact angle of film was about 20 o.The results showed that the dripping agent migration could be effectively delayed by the AAL grafting onto the LLDPE chain and LDHs.When the AAL concentration is 2.0 wt%,the dripping duration of LLDPE-g-AAL and LLDPE/LDHs-g-AAL films at 60 oC is 12 days and 16 days respectively.LLDPE-g-AAL and LLDPE/LDHs-g-AAL films were immersed in 60 oC anhydrous ethanol for 0-6 h.The results show that the contact angle of LLDPE/LDHs-g-AAL film soaked for the same time is larger than that of LLDPE-g-AAL film when the concentration of dripping agent is the same.It is further proved that the precipitation of AAL can be delayed by the grafting of AAL onto the surface of LDHs.The diffusion coefficients of LLDPE/AAL films with different thickness soaked in 60 oC anhydrous ethanol for 0-6 h were calculated by infrared spectra analysis and Fick’s second law.The results show that the diffusion coefficient decreases with the increase of film thickness,which proves that increasing the film thickness can prolong the dripping duration.