Study On Rheology And Weather Resistance Of CNTs/ABS Composites

Acrylonitrile-butadiene-styrene(ABS)is widely used as one of the most common engineering plastics in a variety of occasions,because it combines the excellent properties of its three monomers,and has good mechanical properties,dimensional stability and low production cost.However,with the continuous development of economy,the existing ABS materials are increasingly unable to meet the actual needs,and ABS modified materials are born at the right moment.Carbon nanotubes(CNTs),as a one-dimensional solid material with excellent mechanical properties,electrical conductivity and thermal conductivity,have become ideal fillers in material modification research once discovered.Therefore,the products prepared by CNTs/ABS materials will be able to meet the demand for use in a certain period of time.However,there are few researches on CNTs/ABS materials at present,which makes it impossible to apply them in practical production on a large scale.Therefore,it is very necessary to study the flow performance,machinability and weather resistance of CNTs/ABS material to provide reference for actual production.In this paper,CNTs/ABS composites with CNTs content of 1wt%,3wt% and 5wt%were prepared by melt blending method commonly used in actual production.Standard splines were prepared by injection molding of some of the composite materials,and the improvement of tensile strength and elongation at break was studied by tensile test.The diffraction peaks of CNTs in the composites were observed by X-ray diffractometer.Scanning electron microscopy(SEM)was used to observe the section morphology of the composite after tensile test.The thermal stability and glass transition temperature of the composites were analyzed by differential calorimetric scanning experiments.Some of the prepared composites were used to measure the melt index,and the zero shear viscosity of the composites was obtained approximately.The rheological experiments of the prepared composites were carried out with a rotary rheometer,and the influences of parameters such as temperature,CNTs content and frequency on the fluidity and viscoelasticity of the composites were studied to provide some references for processing.The remaining composite was prepared as permanent group,the tensile and rheological tests were repeated after the remaining composites were placed in the natural environment for one year,then comparing with the original experimental data to study the influence of CNTs on various parameters of ABS material in the range of long-term test,so as to reduce the production risk of enterprises,provide some reference for enterprises in the selection of materials in the product development stage and the formulation of after-sales maintenance standards.The results show that when CNTs are added to ABS material,the tensile strength and elongation at break of the material are significantly improved.However,when the content of CNTs reached 5wt%,the tensile strength reached the highest level,but the increase rate was obviously weakened,and the elongation at break was lower than3wt%.When the content of CNTs was 3wt%,the most obvious diffraction peak appeared around 28° and 40°.Scanning electron microscopy(SEM)showed that the increase of CNTs content could improve the fracture surface morphology of the composites and make the fracture surface more smooth.However,when CNTs reached5wt%,agglomeration could be seen on the fracture surface distinctly,which was one of the reasons that the tensile strength increased slowly and the elongation at break decreased.The glass transition temperature of the composites moved to the high temperature zone with the addition of CNTs,but there was little difference between different CNTs content.The addition of CNTs can reduce the melt index and improve the zero shear viscosity of the composites.When CNTs were added,the viscosity and viscoelasticity parameters of the composites were decreased,and the values were the lowest when the content of CNTs was 1wt%.In addition,the viscosity and viscoelasticity of the material can be significantly reduced with the increasing temperature.The addition of CNTs also makes the shear thinning behavior of the composites more obvious.When the content of CNTs was 3wt%,the tensile strength and elongation at break of the composites decreased the least after one year placement in natural environment.The viscosity and fluidity of the materials will increase after one year,and the content of CNTs has little improvement on them.When CNTs content is 1wt%,the decreasing degree of viscoelastic parameters of composites can be more effectively reduced.