Investigation Of Structure And Properties For Recycled Polypropylene And Nylon 6 Blend

Polypropylene(PP)and modified plastic products are widely used in the daily life owing to its low density,good processability,better mechanical properties and chemical resistant.However,due to the relatively active tertiary hydrogen,the macromolecule will undergo the 3-scission under the comprehensive effect of heat,light and oxygen,which results in the obvious decrease of properties and lots of recycled polypropylene(rPP).Therefore,in this study,based on the changes of macro and microscopic performance in pure and recycled PP,we investigated the miscibility between PP(pure PP and recycled PP)and Nylon 6(PA6)at first.Then,the long chain branched rPP(LCB-rPP)was prepared through reactive extrusion.To a certain extent the"drawbacks" originated from degradation in rPP could be remedied by forming the branched structure.Moreover,the functional monomers were introduced onto the macromolecule during the process of long chain branching,and the compatibility between rPP and PA6 could be further improved under the effect of these monomers.Additionally,the LCB-rPP/PA6 blend was prepared by melting extrusion,and the properties of blend were characterized finally.The main results are as follows:Compared the properties of rPP with the special material of PP for electrical appliance(mPP),the results showed there was a notable decrease of mechanical properties in rPP,and the results from Fourier transformed infrared spectroscopy(FTIR)indicated that the carboxyl groups were formed in rPP during aging and degradation.Simultaneously,the results of FTIR and Molau test demonstrated the reaction between the carboxyl of rPP and the amino of PA6 took place,and the rPP-g-PA6 copolymer was formed during melt mixing.The copolymer could improve the compatibility of blend,and the diameter of dispersed phase in rPP/PA6 decreased markedly.The boundary was obscure compared with the mPP/PA6 blends by scanning electron microscopy(SEM).Form the results of tensile tests,although the comprehensive properties of mPP are superior than that of rPP,the tensile strength of rPP/PA6 blends was increased by 14.78%compared with rPP,while the results of mPP/PA6 were opposite to the former after adding the 20 wt%of PA6 in blend.Moreover,the dynamic mechanical test results exhibited the difference value of glass transition temperature(ATg)was decreased slightly for rPP/PA6 blends.However,the ATg in mPP/PA6 blends had no change.The LCB-rPP with different content of maleic anhydride(MAH)was prepared by reactive extrusion,and the FTIR results revealed the chemical reaction between anhydride and epoxy groups took place in the process of mixing.The branched structure in LCB-rPP exhibited the nucleating effect that could accelerate the crystallization process and improve the crystallinity from the results of melting and crystallization behavior analysis.The rheological results showed the linear structure of rPP was gradually transformed into branched structure,and the rheological parameters such as complex viscosity(?*),storage modulus(G')and loss angle tangent(tan?)etc.were changed clearly.The mechanical properties of LCB-rPP were higher than those of rPP.The tensile strength and Izod notched impact strength were increased as the content of MAH increased.When the content of MAH was 0.5wt%,the impact strength of LCB-rPP was three times than that of rPP.The LCB-rPP/PA6 blends were prepared via melting extrusion,and the effect of different degree of branching on the comprehensive properties of blends was investigated.The mechanical test results exhibited the mechanical properties of blends were improved obviously after mixing with LCB-rPP.When the content of MAH was 0.3 wt%,the tensile strength and flexural strength were 30.26 MPa and 41.31 MPa,which was increased by 14.97%and 41.31%,respectively,compared with rPP/PA6 blends.The chain entanglements in blend were increased with increasing of MAH content,and the viscosity was further increased under the effect,which resulted in the obvious reduction of melt flow rate of blend.The results of XRD showed that the crystal had no change in blend.The results of SEM of the blends showed that,compared with the rPP/PA6 blends,the particle size of the dispersed particles decreased obviously with the addition of LCB-rPP,and the range of particle size distribution was from 0.3 to 1.2 ?m.