This study investigates the mechanical,thermal and morphological properties of rHDPE(Recycled High Density Polyethylene)and a mixture of rPE HD/LD(High and Low Density Polyethylene),both reinforced with rNP(Reclaimed ...This study investigates the mechanical,thermal and morphological properties of rHDPE(Recycled High Density Polyethylene)and a mixture of rPE HD/LD(High and Low Density Polyethylene),both reinforced with rNP(Reclaimed Newsprint Paper)fibres.To enhance the composite properties,the addition of highly grafted maleic anhydride polyethylene wax,as CA(Coupling Agent),and semi crystalline copolymer of propylene and ethylene,as IM(Impact Modifier),was included into the material formulation by a twin-screw extruder.Mechanical and morphological properties were studied on tensile test specimens,prepared by injection moulding,by tensile testing machine and SEM(Scanning Electron Microscope),respectively.Thermal properties,i.e.melting and crystallization behaviour,were investigated by DSC(Differential Scanning Calorimetry).Mechanical analysis showed that the addition of rNP in both composites increased the young modulus and significantly decreased the elongation at break.The DSC results revealed that the addition of the rNP in the rHDPE matrix led to a substantial decrease of crystallinity,which consequently affects the tensile strength of the composite(17 MPa)in contrast to the neat rHDPE(25 MPa).On the contrary,fibre addition in rPE HD/LD matrix had no specific impact on the crystallinity index,but did contribute to the increased tensile strength(26 MPa)when compared with neat rPE HD/LD(16 MPa).SEM photomicrographs of the impact fracture surfaces demonstrated a solid adhesion bond between the natural fibres and the rPE HD/LD matrix.Reclaimed newsprint fibres can thus be considered as a perspective alternative to the inorganic fillers in the rPE HD/LD composite.展开更多
以常见的废弃塑料制品组分高密度聚乙烯(PE-HD)、聚对苯二甲酸乙二醇酯(PET)为实验材料,设置两者的混杂比例为9/1、8/2和7/3,利用螺杆挤出机多次重复熔融再生,并利用体积脉动注塑成型工艺制备增强增韧的混杂塑料回收制品,实现多次回收...以常见的废弃塑料制品组分高密度聚乙烯(PE-HD)、聚对苯二甲酸乙二醇酯(PET)为实验材料,设置两者的混杂比例为9/1、8/2和7/3,利用螺杆挤出机多次重复熔融再生,并利用体积脉动注塑成型工艺制备增强增韧的混杂塑料回收制品,实现多次回收制品力学性能的显著提高。分析了不同注塑工艺对样品微观结构的影响机理,证明了体积脉动注塑成型引入的脉动应力场能有效提高不相容组分间的相容性,诱导掺杂相原位成纤和材料结晶形态的改变,构建互联杂化串晶结构。力学测试结果表明,在PE-HD和PET的混杂比例为9/1时,体积脉动注射成型制备的混杂回收材料屈服强度和冲击韧性达38.7 MPa和165 k J/m^(2),与稳态注射相比有54.8%和3675.7%的提升。混杂比例为7/3时,样品的屈服强度和冲击韧性为31.0 MPa和11.6 k J/m^(2),与稳态注射相比仍有14.8%和216.1%的提升。展开更多
文摘This study investigates the mechanical,thermal and morphological properties of rHDPE(Recycled High Density Polyethylene)and a mixture of rPE HD/LD(High and Low Density Polyethylene),both reinforced with rNP(Reclaimed Newsprint Paper)fibres.To enhance the composite properties,the addition of highly grafted maleic anhydride polyethylene wax,as CA(Coupling Agent),and semi crystalline copolymer of propylene and ethylene,as IM(Impact Modifier),was included into the material formulation by a twin-screw extruder.Mechanical and morphological properties were studied on tensile test specimens,prepared by injection moulding,by tensile testing machine and SEM(Scanning Electron Microscope),respectively.Thermal properties,i.e.melting and crystallization behaviour,were investigated by DSC(Differential Scanning Calorimetry).Mechanical analysis showed that the addition of rNP in both composites increased the young modulus and significantly decreased the elongation at break.The DSC results revealed that the addition of the rNP in the rHDPE matrix led to a substantial decrease of crystallinity,which consequently affects the tensile strength of the composite(17 MPa)in contrast to the neat rHDPE(25 MPa).On the contrary,fibre addition in rPE HD/LD matrix had no specific impact on the crystallinity index,but did contribute to the increased tensile strength(26 MPa)when compared with neat rPE HD/LD(16 MPa).SEM photomicrographs of the impact fracture surfaces demonstrated a solid adhesion bond between the natural fibres and the rPE HD/LD matrix.Reclaimed newsprint fibres can thus be considered as a perspective alternative to the inorganic fillers in the rPE HD/LD composite.
文摘以常见的废弃塑料制品组分高密度聚乙烯(PE-HD)、聚对苯二甲酸乙二醇酯(PET)为实验材料,设置两者的混杂比例为9/1、8/2和7/3,利用螺杆挤出机多次重复熔融再生,并利用体积脉动注塑成型工艺制备增强增韧的混杂塑料回收制品,实现多次回收制品力学性能的显著提高。分析了不同注塑工艺对样品微观结构的影响机理,证明了体积脉动注塑成型引入的脉动应力场能有效提高不相容组分间的相容性,诱导掺杂相原位成纤和材料结晶形态的改变,构建互联杂化串晶结构。力学测试结果表明,在PE-HD和PET的混杂比例为9/1时,体积脉动注射成型制备的混杂回收材料屈服强度和冲击韧性达38.7 MPa和165 k J/m^(2),与稳态注射相比有54.8%和3675.7%的提升。混杂比例为7/3时,样品的屈服强度和冲击韧性为31.0 MPa和11.6 k J/m^(2),与稳态注射相比仍有14.8%和216.1%的提升。
