Study On Hydrophobic Polypropylene With High Toughness

Polypropylene(PP)has many advantages,such as excellent chemical stability and processing properties.PP can be used as fiber,coated products,pipes and sheets.However,poor hydrophobic properties and low toughness limit its application to some extent,so it is necessary to modify these disadvantages.Coating and surface treatment are usually methods to prepare hydrophobic PP,but these methods also have many disadvantages,such as complicated process technology and hard treatment conditions.It is a valuable issue how to prepare hydrophobic PP with low cost and high toughness through simple process method.In this paper,low surface energy organic filler PVDF,PDMS,POE and modified TiO2 were blended with polypropylene to prepare a series of hydrophobic PP.The effects of types and concentration of organic and inorganic fillers on the water contact angle,mechanical properties,rheological behavior and morphologies of hydrophobic PP were investigated.We prepared hydrophobic PP composites with good hydrophobic and high toughenss with the help of synergism effect of organic and inorganic fillers.The research results are as follows:(1)Silane coupling agents can react with hydroxyl groups of TiO2 and coated on the surfaces of TiO2 by Ti-O-Si bond.PP/TiO2 modified with KH-570 nanocomposites exhibit good hydrophobic and impact properties.When the concentration of TiO2 is 7 wt%,the water contact angle of PP/TiO2 nanocomposite increases to 95°,which is 32%higher than that of pure PP,and the notched Izod impact strength is 10.3 kJ/m2,3.6 times higher than that of pure PP.The good distribution of TiO2 in the PP matrix is the key reason for good hydrophobic and mechanical properties.(2)The introduction of hydroxyl PDMS can improve hydrophobic and impact properties of PP.When the concentration of PDMS is 10 wt%,the notched Izod impact strength of PP/PDMS composite shows a peak value,9.86 kJ/m2,about 3.5 times higher than that of pure PP.When the concentration of TiO2 is 5 wt%,PP/addition PDMS/TiO2 nanocomposites crosslinked by DCP show high notched Izod impact strength,tensile strength and bending strength,which can be attributed to the synergistic effect of crosslinking of PDMS,degradation of PP and toughening of TiO2.PP/PDMS/TiO2 nanocomposite with 10 wt%TiO2 exhibits good hydrophobic property and the water contact angle reaches 95°.G' and G"of PP/PDMS/TiO2 nanocomposites decrease sharply with the concentration of TiO2 and PDMS increasing.(3)When the concentration of TiO2 is 5 wt%,thermal crosslinking PP/addition PDMS/TiO2 nanocomposites show high notched Izod impact strength and tensile strength.The notched Izod impact strength of PP/PDMS/TiO2 nanocomposite with 10 wt%PDMS and 5 wt%TiO2 is 11.92 kJ/m2,about 4.2 times higher than that of pure PP.PP/PDMS/TiO2 nanocomposites with 10 wt%TiO2 show good hydrophobic property and the water contact angle reaches 101°.The morphologies of PP/PDMS/TiO2 nanocomposites exhibit that TiO2 are dispersed mainly in the PDMS phases and form core-shell structure,the addition of PDMS can improve effectively dispersion of TiO2.(4)The introduction of PDMS and POE can enhance effectively the toughness of PP.When the component of PP/PDMS/POE composite is 85/15/10,because of good dispersion of PDMS and POE,the notched Izod impact strength shows a peak value,18.81 kJ/m2,about 6.5 times higher than that of pure PP.After TiO2 adding,the toughness and rigidity of PP/PDMS/POE composites are further improved.When the component of PP/PDMS/POE/TiO2 nanocomposite is 85/15/10/7,the notched Izod impact strength is up to 20.76 kJ/m2,about 7.2 times higher than that of pure PP.The hydrophobic properties of PP/PDMS/POE/TiO2 nanocompsites increases with the increase of PDMS concentration and have no close relationships with the content of Ti02.(5)The introduction of PVDF can improve effectively the hydrophobicity and toughness of PP and reduce the bending strength.Because of the synergistic effect of TiO2 and PVDF,PP/PVDF/TiO2 nanocomposites show high rigidity,toughness and hydrophobicity.PVDF can be coated with PDMS and the dispersion of PVDF become good,which can increase further the notched Izod impact strength,hydrophobicity and melting viscosity.PP/PVDF/PDMS composite exhibit island-matrix morphologies,the sizes and distances of dispersed phase are the main factors to determine the toughness and hydrophobicity of composites.