Research On Attapulgite/Polypropylene Nanocomposite Materials

Polypropylene(PP)/attapulgite(ATP) nanocomposites were prepared by means of meltblending with styrene grafted with the modified polypropylene as compatilizer. The mainobjective is to prepare a new type of nanocomposite with excellent quality by improving thecompatibility between ATP and PP with modified ATP and the self-made compatilizer. Therelationship between material structure and properties was studied, and the effect of thermaltreatment on the performance of composite was analyzed. The main contents are as following:Firstly, ATP was treated with four different modifier, the structures of modified ATP werecharacterized with FTIR, the best dosage and effect of the different modifiers werecharacterized by the activity index and oil-absorbed value. The results show that, NDZ105、CTMAB、KH570can reacted with ATP, no bonding interaction between citric acid and ATP,and only physical adsorption in action. Synthetic analysis indicates that, when the percentageof KH570is2%, the best modification result is gained.Secondly, graft copolymerization of maleic anhydride(MAH) and styrene(St) ontopolypropylene was prepared by aqueous suspension. The effects of reaction conditions ongrafting ratio and grafting efficiency were studied, and the structure of the product wascharacterized by FTIR and XRD. The optimum conditions was as follows:0.6%ofinitiator-to-PP,12%of monomer-to-PP, St∶MAH=1∶1, interface agent is cyclohexane,swelling temperature40℃, swelling time30min, reaction time2h, and grafting ratio is6.38%, grafting efficiency is53.42%. The XRD analysis showed that PSM can be used as βnucleate agent.Thirdly, PP/ATP nanocomposite was prepared by melt extrusion, the structure andproperties were characterized. The addition of ATP did not change the crystalline of PP, butenhanced its crystallinity. The test of mechanical properties shows that the addition ofmodified ATP and self-made compatilizer can improve the comprehensive properties of PP.The tensile strength of the composite was increased by6~12%and elongation at breakdecreased slightly, the impact strength of the composite was increased by25~31%. Theaddition of beta nucleating agent and POE can synergy with ATP to increase the impactstrength significantly.Finally, thermal treatment was carried out to the composite, and the affect of heattreatment to composite was studied. The results show that when heat treatment was carriedout to the composite for a short time, the composite was affected by thermal annealing, ATP was effective in promoting the crystallization of PP and the tensile strength improved forAlpha crystal increasing. When PSM was compatilizer, the beta crystal can generate in theprocess of thermal annealing, and the tensile strength of the composite was increased by10.8%, the impact strength of the composite was increased by8.5%.