Okubo Hikaru, Kaneyasu Haruka, Kimura Tetsuya, Phanthong Patchiya, Yao Shigeru
Collaborative Research Institute for Creation of Functional and Structural Materials, Fukuoka University, Fukuoka 814-0180, Japan.
Facility of Engineering, Graduate School of Chemical Engineering, Fukuoka University, Fukuoka 814-0180, Japan.
Polymers (Basel). 2021 Mar 27;13(7):1058. doi: 10.3390/polym13071058.
Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young's modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.
每年都会产生越来越多的塑料垃圾，造成环境污染和资源损失。回收利用是一种解决办法，但回收塑料的机械性能往往不如原生塑料。然而，研究表明，在挤出前将聚合物保持在熔融状态可以恢复其机械性能；因此，我们提出了一种带有熔融树脂储存器（MSR）的双螺杆挤出机，它是螺杆区和双螺杆挤出机出料口之间的一个腔体，在双螺杆区混合后保留熔融聚合物，从而影响聚合物性能。制备了再挤出的回收聚乙烯（RPE）颗粒，并对原生聚乙烯（PE）、未挤出的RPE以及使用和不使用MSR制备的再挤出RPE模制品的拉伸性能和微观结构进行了评估。至关重要的是，MSR挤出的RPE模制品的断裂伸长率比原始RPE模制品高七倍，并且MSR挤出的RPE模制品的杨氏模量与原生PE模制品相当。MSR挤出的RPE和原生PE模制品都含有类似的条纹状片晶。因此，MSR再挤出通过优化微观结构提高了回收聚合物的机械性能。MSR的使用将有助于将废塑料作为具有广泛工业应用的增值材料进行再利用。
