Preparation And Properties Of Nano-CaCo₃/waste Polyethylene/styrene-butadiene-styrene Block Polymer Modified Asphalt

With the rapid development of the take-out and express delivery in modern life,more and more plastic products are used in commodity packaging.These plastic products are turned into packaging waste after being used,and it will bring "white pollution" to us.It caused huge pressure to the ecological environment,so the recycling of packaging waste has become a hot topic.Waste polyethylene(WPE)and styrene-butadiene-styrene triblock copolymer(SBS)were used as raw materials to prepare WPE/SBS composite materials in this paper,and its physical properties and micro-morphology were analyzed.WPE/SBS composite material was used as a modifier to prepare modified asphalt,and its comprehensive performance was tested to achieve the purpose of WPE recycling and reducing the economic cost of modified asphalt.First,WPE was used as the matrix by extrusion granulation,and then SBS was used as a modifier to prepare WPE/SBS composite materials with different mass ratios by blending extrusion method.The test results showd that the addition of SBS can enhance the elasticity of WPE.The maximum elongation at break of the composite is 625%,which is higher than the elongation at break of WPE.The mixing of SBS and WPE is only physical blending,and SBS improves the thermal stability of WPE.As the amount of SBS increasing,more and more pore structures appeared in the composite material.When the amount of SBS added reaches 50 wt%,the composite material formed a type of polymer alloya,which two blends formed a macroscopic homogeneous and microscopic heterogeneous.In addition,WPE/SBS composite material was used as a modifier to prepare composite modified asphalt with different addition ratios by melt shearing.WPE improves the rutting resistance of modified asphalt.The maximum amount of WPE added in the composite modifier can reach 40 wt%,the comprehensive performance of modified asphalt meets the specifications of road modified asphalt.After that,the best composition ratio of the composite modifier is WPE:SBS=4:6,performed performance tests on the composite modified asphalt prepared when the amount of the composite modifier is different,and the optimal amount of the composite modifier is 4 wt%.Finally,nano-CaCO3 with different length-to-diameter ratios was used for secondary modification.The performance test found that nano-CaCO3 whiskers can enhance the ductility of the composite modified asphalt,and nano-CaCO3 particles can enhance its rutting resistance.These studies provide experimental basis for the preparation of cost-effective modified asphalt,as well as ideas for the recycling of packaging waste.