Preparation And Properties Research Of Modified Polypropylene And Polyamide 6 Composite Materials

As an engineering plastic,polyamide 6 has considerable development space and good application prospects in many fields due to its excellent properties such as strong corrosion resistance,excellent design-ability,and low density.However,it is an insulator,and its surface resistance is relatively high.During the production,transportation,and use,it can easily accumulate a large amount of charge on the surface,causing a fire hazard.The mechanical properties and thermal stability of poly-amide 6 also need to be improved.These problems limit its application.This subject aims at the problem of high surface resistance,by adding carbon nanotube filler to increase its electrical conductivity and reduce the high surface resistance of poly-amide materials.When a single polymer is blended with carbon nanotubes,a higher carbon nanotube mass fraction is often required,which will reduce the overall performance of the material,there are regional differences in conductive ability on the surface,and unstable attachment of conductive fillers.Therefore,polypropylene and polyamide 6 which are incompatible with polyamide 6 are first melt blended to prepare a two-phase polymer forming a bi-continuous structure.Taking polyamide 6 polypropylene two-phase polymer as the matrix,carbon nanotube polypropylene glass fiber polyamide 6 composite material was prepared by adding filler carbon nanotubes with different mass fractions?0%to 6%?.The analysis characterized the structure and properties of the prepared materials.When added to 5%by mass carbon nanotubes,the surface resistivity reached 9.384×10¹⁴ohms.Compared with1.816×10¹⁵ohms by adding 1%carbon nanotubes,the surface resistivity decreased by48.33%.Formed an excellent conductive network.The initial decomposition temperature also shows an upward trend due to the gradual addition of carbon nanotubes,and the thermal performance has been significantly improved.But the addition of carbon nanotubes will make its fluidity worse.When the mass fraction of carbon nanotubes is low,the melt index decreases but changes little.With the continuous increase of the mass fraction of carbon nanotubes,the melt index begins to decrease significantly,showing a general downward trend.In terms of mechanical properties,the bending properties of composite materials have been significantly improved.Although the anomaly occurred at 3%compared with 2%,the bending strength decreased by 2.0MPa,but overall the bending strength is still gradually increasing.When the carbon nanotube mass fraction is added to 6%,it can reach 71.9MPa.In contrast,the bending strength of pure polypropylene polymer is only 45.7MPa,so the addition of carbon nanotubes can better improve the mechanical properties of the composite material.Subsequently,this subject studied the effects of different temperature relaxation heat setting on the orientation structure of polypropylene fibers.According to the experimental results of density test and linear density test,temperature has no obvious effect on the relevant parameters of polypropylene fiber.From the experiment of measuring the degree of orientation by sound velocity method,it can be seen that there are obvious rules.As the relaxation heat setting temperature increases,the degree of orientation of the polypropylene molecule shows a downward trend,and the modulus and sound velocity also have similar trends.The difference in the data change range infers that the softening point of the sample polypropylene fiber is between 130?and 140?.Combined with the results of the tensile data,it can be inferred that the high temperature does have an effect on the polypropylene fiber structure.After baking at high temperature,the increase of the elastic modulus and the decrease of the modulus of the polypropylene fiber both indicate the decrease of its strain capacity.The suitable processing temperature of the polypropylene fiber hernia patch can be found from further experiments.Finally,we used different concentrations of SCR-300 flame retardant to soak the PA6fiber.After natural drying,orientation,curling elasticity,stretching and burning were measured..After fully washing the samples,the samples were naturally dried and compared for orientation,curling,stretching,and burning.The results show that the flame retardant has little effect on the orientation,crimp and tensile properties of PA6 fiber.The flame retardant performance has been improved.For the samples with high flame retardant concentration,the flame will quickly weaken or even extinguish after leaving the flame.The smokeless time is also longer than the original PA6 high elastic yarn.Even after washing and drying,the sample has better flame retardant performance than the original PA6 high elastic yarn.