Investigation On The Antistatic Performance Of Polypropylene And Its Composites

Polypropylene,as a thermoplastic polymer,has the advantages of low price,easy processing and excellent performance.Polypropylene itself and its composite materials with glass fiber(GF)have been widely used as engineering plastics in many fields such as home appliances,automobiles,and medical care.However,PP has low water absorption and strong electrical insulation.Its surface resistivity is 1016~1018W/sq,which makes it easily to accumulate static charges in industrial production and daily life.The accumulated static charges may cause a series of hazards and accidents.It is of great significance to prepare PP and its composite materials with excellent antistatic properties.For the first time,PP and PP/Glass fiber(GF)composites were modified with organic salts to prepare polypropylene and polypropylene composites with good antistatic properties and excellent mechanical properties.The main research contents are as follows:1.Antistatic study of organic salts on PP: The effect of two organic salts(OSs),tributyl(octyl)phosphonium bis(trifloro-methanesulfonyl)imide(TBOP-TFSI)and lithium bis(trifloro-methanesulfonyl)imide(Li-TFSI)on the antistatic and mechanical properties of PP was studied.It was found that the surface resistivity of PP decreased to less than 1012W/sq with the addition of 3wt% OS.However,OSs will form a large microdomain in the PP matrix because the polarity of PP differs greatly from OS.The interaction between maleic anhydride graft polypropylene(MAPP)and Li-TFSI was studied and found that Li-TFSI has good compatibility with MAPP.Therefore,MAPP,as a compatiblizer,can improve the dispersion of Li-TFSI in PP matrix and prepare PP materials with antistatic properties and good mechanical properties2.Antistatic study of organic salts on PP/GF composites: The effects of two organic salts on the antistatic and mechanical properties of PP/GF composites were systematically studied.It was found that glass fibers and organic salts had synergistic effects on the antistatic properties and mechanical properties of the system.On the one hand,glass fiber networks provide conductive orbits for organic salts,and organic salts transfer charge on their surfaces,which improves the antistatic performance of the system and reduces the antistatic percolation threshold of organic salts to 0.25wt%.On the other hand,the organic salt improves the interfacial adhesion between the glass fiber and the PP matrix,which increases the tensile strength of the system greatly.In addition,the compound organic salts can further improve the antistatic effect of organic salts.When the ratio of Li-TFSI to TBOP-TFSI is 1:5,the antistatic percolation threshold of organic salts reduces to 0.06wt%.Moreover,the effects of the hydroxyl content on the surface of glass fiber and the structure of the organic salt ions on the antistatic property and mechanical properties oe composites were further studied.It is found that only when the surface hydroxyl content of glass fiber is appropriate,the charge transfer ability of salt on its surface canf th be optimal.The increase of the cationic radius of organic salt and the reduction of anion steric hindrance can enhance the mobility of cation,thus further improving the antistatic effect of organic salts.3.Antistatic and mechanical study of MAPP on PP/GF/Li-TFSI composites: The effects of MAPP on the mechanical properties and antistatic properties of PP/GF/Li-TFSI/MAPP composites were systematically studied.PP/GF/Li-TFSI/ MAPP composites with good antistatic mechanical properties were prepared by adjusting the ratio of Li-TFSI and MAPP.When Li-TFSI loading is 0.175wt% and MAPP content is 9wt%,the conductivity of the system is more than 10-12Scm-1 and the tensile strength is over 60 MPa.