Preparation And Technological Design Of EPDM-modified PS Materials

Polystyrene(PS)is the fourth largest general-purpose resins in the world today,and it has a wide range of applications.However,due to the rigid benzene ring structure in PS molecules,its compliance properties are extremely low,so the mechanical properties of pure PS plastics are poor.Its processing performance is greatly limited.Therefore,PS must be modified by physical or chemical methods to achieve the strength and toughness requirements of the materials.From the application area of PS plastics,adding a certain amount of toughening agent to improve the toughness and impact resistance of PS materials,and adding an appropriate amount of fillers to reduce the production cost of PS plastics have become urgent problems in the research of application of PS plastics.In order to prepare PS plastic with high toughness and high impact resistance,ethylene propylene diene monomer(EPDM)was used as a toughening agent,and 325mesh light Ca CO₃was selected as a filler.In addition,in order to improve the stability of the product At the same time add a certain proportion of auxiliary reagents,such as dioctyl phthalate(DOP),titanate coupling agent,antioxidant 1010,lubricant calcium stearate and so on.After the above raw materials are fully mixed according to a certain mass ratio,they are blended and extruded through a twin-screw extruder to obtain the target product EPDM modified PS plastic(EMPS),which is injection molded into a standard spline by an injection molding machine.The spline was tested for tensile properties using a universal electronic testing machine,the impact strength was tested using a cantilever impact testing machine,and the melting index was measured using a melting index tester.The effects of EPDM ratio and light Ca CO₃content on the mechanical properties and melt flow properties of modified PS plastics were further explored in the experiment.The experimental results show that when PS and EPDM are blended,when the EPDM content exceeds 30%,the impact strength and elongation at break of the system are greatly improved,and the decline in tensile strength begins to slow.With the increase of the filler's light Ca CO₃content,although the tensile strength,elongation at break,and impact strength of EPDM-modified PS plastics have decreased,they still fully meet the processing requirements of the product in a large range.When the ratio of EPDM to PS is4:6 and the content of light Ca CO₃is 30%,the tensile strength of EMPS reaches 17.5MPa,the impact strength reaches 173.4 J/m,and the melting index reaches 1.9 g/10 min.The best performance,and higher than the performance indicators of impact polystyrene(PS-I)resin(GB/T 37198-2018).Therefore,the modified PS plastic prepared by this process can be used as a substitute for HIPS,which is completely suitable for the processing and production of plastic jewelry.Finally,based on the results of this experimental study,a modified PS plastic processing plant with an annual output of10,000 t was designed,and its material,energy accounting,and technical and economic analysis were performed.