The Preparation And Properties Of Polypropylene/Montmorillonite Composites

Polypropylene(PP)as the third largest generic plastic in the world has been widely used in automobiles,household appliances,packaging and other fields.However,the disadvantages such as poor toughness,easy embrittlement under low temperature and easy aging of ordinary PP severely limit its Popularization and application.At present,the filling modification of PP using montorillonite clay minerals(MMT)as the filling modifier has attracted widespread attention.In this paper,the PP/MMT nanocomposites with excellent comprehensive performances was prepared through introducing montmorillonite modified by quaternary phosphonium(OMMT)and ethylene/octane copolymer(POE)into the PP matrix by the melt extrusion.The main research works are as follows:First,organic modification of MMT with positive tributyl myristyl chloride phosphine(TTPC)was conducted,and the influences of the process conditions such as modifier dosage,reaction time and reaction temperature on the oil absorption value of MMT were examined.The structure and thermal stability of the modified MMT were characterized by infrared spectroscopy(FTIR),small Angle X-ray diffraction(SAXS),electronic scanning electron microscope(SEM)and thermogravimetric(TG),and other means.The results showed that the oil absorption value of OMMT was the highest under the conditions that the mole ratio between CEC and TTCP was 3:2 in Na-MMT,and the reaction temperature and reaction time was 65℃and 4 h,respectively.Moreover,the ultrasonic pretreatment could further increase the oil absorption value of the OMMT.The results of structure and performance test indicated that the layer spacing of MMT increased from 1.23 nm to 2.01 nm by inserting TTPC into the layers;agglomeration was significantly weakened;and the thermal stability was significantly superior to the MMT modified by cetyl trimethyl ammonium chloride.Secondly,the mechanical property of PP modified by MMT using POE grafting maleic anhydride(POEM),POE grafting double monomer MAH and 2-hydroxyethyl acrylate(POEHM)as compatibilizers respectively was comparatively studied.The structure,melt crystallization behavior and thermal stability of PP modified by MMT were analyzed using FTIR,differential scanning calorimetry(DSC),SAXS,X-ray diffraction(XRD),SEM and TG,and the blocking performance for organic solvent of benzene liquid of composite material was examined.Mechanical performance analysis showed that the tensile and bending properties of the composite material adopting POEHM and POEM as compatibilizers decreased slightly compared with pure PP,but was obviously higher than the PP toughened by POE alone;the toughening effect of PP was superior to adding POEM,the notched impact strength maximum value of PP by adding POEHM was 19.78 kJ/m~2 increasing by 196%compared with pure PP.Structure analysis of composite materials demonstrated that the modified MMT layers dispersed uniformly in PP matrix in the form of stripping due to the effect of"bridging"between POEM,and POEHM.Melt crystallization behavior analysis showed that the introduction of compatibilizers on PP had little impact on melt temperature;POEHM could induce PP to generate moreα-crystalline than POEM;stripping of organic MMT was good for reducing the crystallite size of PP,and could increase the crystallization temperature by 4.2℃.TG analysis showed that thermal stability of composite materials was the best using POEHM as compatibilizer,of which the half-life temperature raised by 86℃compared with pure PP.The sequence of barrier ability for organic solvent of benzene liquid of the composite materials was:PP/OMMT>PP>PP/OMMT/POEHM>PP/OMMT/POEM>PP/OMMT/POE...