Titone Vincenzo, Gulino Emmanuel Fortunato, La Mantia Francesco Paolo
Department of Engineering, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy.
INSTM, Consortium for Materials Science and Technology, Via Giusti 9, 50125 Florence, Italy.
Polymers (Basel). 2023 Mar 9;15(6):1367. doi: 10.3390/polym15061367.
Anything that is not recycled and/or recovered from waste represents a loss of raw materials. Recycling plastics can help to reduce this loss and to reduce greenhouse gases, improving the goal of the decarbonization of plastic. While the recycling of single polymers is well assessed, the recycling of mixed plastics is very difficult because of the strong incompatibility among the different polymers usually present in urban waste. In this work, heterogeneous mixed polymers, i.e., polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyethylenetherephthalate (PET) were processed using a laboratory mixer under different conditions of temperature, rotational speed and time to evaluate the effect of the above parameters on morphology, viscosity and mechanical properties of the final blends. Morphological analysis shows a strong incompatibility between the polyethylene matrix and the other dispersed polymers. The blends show, of course, a brittle behavior, but this behavior slightly improves with decreasing temperature and increasing rotational speed. A brittle-ductile transition was observed only at a high level of mechanical stress obtained by increasing rotational speed and decreasing temperature and processing time. This behavior has been attributed to both a decrease in the dimensions of the particles of the dispersed phase and to the formation of a small amount of copolymers that act as adhesion promoters between matrix and dispersed phases.
任何未从废物中回收利用的物质都意味着原材料的损失。回收塑料有助于减少这种损失并减少温室气体排放，从而推动塑料脱碳目标的实现。虽然单一聚合物的回收情况已得到充分评估，但混合塑料的回收却非常困难，因为城市垃圾中通常存在的不同聚合物之间具有很强的不相容性。在这项工作中，使用实验室混合器在不同的温度、转速和时间条件下对非均相混合聚合物，即聚乙烯（PE）、聚丙烯（PP）、聚苯乙烯（PS）和聚对苯二甲酸乙二酯（PET）进行加工，以评估上述参数对最终共混物的形态、粘度和机械性能的影响。形态分析表明，聚乙烯基体与其他分散聚合物之间存在很强的不相容性。当然，这些共混物表现出脆性，但随着温度降低和转速提高，这种行为会略有改善。仅在通过提高转速、降低温度和加工时间获得的高机械应力水平下才观察到脆韧转变。这种行为既归因于分散相颗粒尺寸的减小，也归因于少量共聚物的形成，这些共聚物充当基体与分散相之间的粘合促进剂。
