Preparation And Properties Of PP/HYBRAR/MOS Blends

High-performance of general-purpose plastics is one of the important research subjects in the polymer materials at present and in the future.Blending modification is a major route to realize the high-performance of general-purpose plastics.In this thesis,the blends with good comprehensive properties were prepared by the melt-mixing using the hydrogenated styrene thermoplastic(HYBRAR)elastomer as toughening agent and the basic magnesium sulfate whisker(MOS)as filler.The influence of HYBRAR and MOS on the flow,crystallinity,thermostability,mechanical,and combustion properties of the blends were investigated.This thesis includes three parts:Part one,orthogonality experiment was employed to explore the influence of mixer blending process conditions on the mechanical properties of the blends.A series of PP/HYBRAR blends were prepared in different blending process conditions and the data collected by mechanics performance testing was used to determine the optimal blending process conditions,where mechanical performance are proved to be influenced obviously by blending temperature and time.According to experimental results,the blending process conditions were determined as fellows:the blending temperature was 180?,the time 10min,and the speed 60 r/min.Part two,on the basis of the blending process condition,the PP/HYBRAR blends were prepared to explore the effect of HYBRAR on the flow,crystallinity,thermostability and mechanical properties of the PP/HYBRAR blends.The results showed that with the increase of HYBRAR,the liquidity and thermal stability decrease.And HYBRAR had no influence on the crystal structure of PP crystallization,and the interplanar spacing almost had no change.The melting point decreased with the increase of HYBRAR,and the depressions in melting temperature of PP phase in the blends indicated that there may be a strong intermolecular interaction between PP and HYBRAR.With the increase of HYBRAR,the crystallization temperature increased,but the crystallinity and the degree of subcooling decreased.Besides the non-isothermal crystallization kinetics of blends were calculated by Jeziorny,Ozawa and Mo methods.The Jeziorny and Mo methods were more suitable to describe the non-isothermal crystallization of the blends.The speed of crystallization and the reduction of active energy of PP crystallization were increased by the incorporation of HYBRAR.The mechanical results revealed that with the 20wt%HYBRAR,the impact strength of the PP/HYBRAR blend at room temperature and 0?and-18?was 24.72 kJ/m~2,14.37 kJ/m~2,8.96 k J/m~2,respectively,and was enhanced by 10.66 times,10.50 times and 16.57 times compared with that of the pure PP.The tensile strength and flexural strength and Shaw hardness of the modified blends were slightly decreased as expected by the introduction of the flexible HYBRAR.Part three,in order to enhance the strength and stiffness of PP/HYBRAR blend,a series of PP/HYBRAR/MOS were prepared by adding MOS,and the effect of MOS on the mechanical and flame retardance properties were discussed.The results showed that the dispersion of the MOS in polymer was improved by incorporation of silane coupling agent KH-570.The introduction of modified MOS microparticles into a blends matrix,which contains an optimum amount of the MOS(20wt%),pushes the impact strength to maximum levels and further increases the flexural strength,hardness and thermostablity.Besides,a visibly improvement of Limiting Oxygen Index,as high as 25.8%,was also achieved in the ternary blending material with 50wt%MOS loading.