| Polystyrene（PS）is incompatible with polymethyl methacrylate（PMMA）,hence it is necessary to use a compatibilizer in making the blend of PS/PMMA.Polystyrene（PS）-polymethyl methacrylate（PMMA）-based Janus nanosphere was prepared by seed emulsion polymerization,and the polystyrene-nano silica-polyhydroxyethyl methacrylate（PS-Si O2-PHEMA）-based Janus nanosphere was also prepared by atom transfer radical polymerization（ATRP）in a Pickering emulsion.As two different shape nanospheric compatibilizers,the compatibilization effect of Janus nanospheres on PS/PMMA,which is a typical incompatible blend system,was studied as follows:1.PMMA nanospheric particles with a diameter size of 89 nm were synthesized by conventional emulsion polymerization,and then it was used as a seed for seed emulsion polymerization of styrene,and PS nanospheric particles were grown on the surface of PMMA nanospheres to obtain double spherical（dumbbell）PS-PMMA-based Janus nanospheres（JNPs）with an average particle size of 190 nm.The morphology and chemical properties of the JNPs nanospheres were characterized by a series of techniques such as SEM,EDS,FTIR,and etc.2.The above-mentioned dumbbell-type PS-PMMA-based Janus nanospheres（JNPs）were used as compatibilizing additives.PS was melt blended with PMMA and JNPs with a miniature extrusion and injection molding machine to prepare the PS/PMMA/JNPs composites with increment of JNPs.As the mass ratio of PS to PMMA was maintained at40/60,the addition amount of JNPs was 1.0wt%-5.0wt%,for the PS/PMMA/JNPs composites their impact strength,tensile strength,SEM,DSC,rheological behaviors and other properties were tested.The experimental results show that JNPs can significantly improve the compatibility of PS/PMMA/JNPs composites.When the addition of JNPs was4.0wt%,JNPs had the best compatibilization effect on the blend of PS/PMMA/JNPs.The tensile strength and impact strength of the obtained PS/PMMA/JNPs composites were increased by 55.4%and 34.5%,respectively.The transparency and rheological properties of the PS/PMMA/JNPs composites were also significantly improved.3.The nano-Si O2 was modified withγ-aminopropyltriethoxysilane（KH-550）and 2-bromoisobutyryl bromide,and the surface-modified products（Si O2-NH2 and Si O2-Br）were obtained in turn.The Si O2-Br was dispersed and stabilized in an oil-water（toluene/water）Pickering emulsion,and then it was simultaneously carried out an ATRP reaction at the oil-water interface in this Pickering emulsion,so that PS branch chains and PHEMA branch chains were grafted onto nano-Si O2 between the oil and water interfaces in this Pickering emulsion to obtain the brush-type PS-Si O2-PHEMA-based Janus nanospheres（Si O2@JNPs）with a diameter of 100 nm.This brush-type Janus nanospheric structure,morphology and chemical properties were tested and characterized by TEM,SEM,DSC,TGA,and etc.4.The above-mentioned brush-type PS-Si O2-PHEMA-based Janus nanospheres（Si O2@JNPs）were used as compatibilizers,PS and PMMA were melt blended to obtain the composites of PS/PMMA/Si O2@JNPs by extrusion and injection.The properties of PS/PMMA/Si O2@JNPs composites were measured by impact,tensile,SEM,DSC and rheological tests.The results show that the Si O2@JNPs nanospheres can significantly improve the compatibilization on PS/PMMA/Si O2@JNPs composites.When the amount of Si O2@JNPs nanosphere compatibilizer was 0.9wt%,for example,the tensile strength and impact strength of the PS/PMMA/Si O2@JNPs composite was increased by 17.7%and19.6%,respectively,and the transparency and rheological properties of this composites is also significantly improved. |
PDF Full Text Request