Zhiltsova Tatiana, Oliveira Mónica S A
TEMA-Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
LASI-Intelligent Systems Associate Laboratory, 4800-058 Guimarães, Portugal.
Polymers (Basel). 2025 Jun 3;17(11):1556. doi: 10.3390/polym17111556.
The increasing demand for sustainable materials has renewed interest in recycling polyolefins, particularly polypropylene (PP), due to its widespread use and environmental persistence. Post-consumer recycled polypropylene (PP), however, often exhibits compromised properties from prior exposure to thermal, oxidative, and mechanical degradation. This study investigates the potential of using post-consumer PP in melt-blended extrusion formulations with virgin PP (PP), focusing on how different PP contents affect processability, thermal stability, oxidative resistance, and mechanical performance. Blends containing 25%, 50%, and 75% PP, as well as 100% PP and virgin PP, were evaluated using melt flow index (MFI), differential scanning calorimetry (DSC), oxidation induction time (OIT), thermogravimetric analysis (TGA), and tensile testing. Results show that increasing PP content improves polymer fluidity and thermal stability under inert conditions but significantly reduces oxidation resistance and ductility. However, the 25% PP blend demonstrated a favourable balance between performance and recyclability, presenting 96% of the elastic modulus and 101% of the yield strength of PP. Homogenization by extrusion improved the oxidative stability of recycled PP by 22% compared to its non-extruded form. These findings support the use of low-to-moderate levels of PP in virgin PP for applications requiring predictable and tunable performance. contributing to circular economy goals.
对可持续材料日益增长的需求，重新引发了人们对回收聚烯烃，尤其是聚丙烯（PP）的兴趣，这是由于其广泛应用和环境持久性。然而，消费后回收的聚丙烯（PP），由于先前暴露于热、氧化和机械降解，其性能往往会受到影响。本研究调查了在与原生PP（PP）的熔融共混挤出配方中使用消费后PP的潜力，重点关注不同PP含量如何影响加工性能、热稳定性、抗氧化性和机械性能。使用熔体流动指数（MFI）、差示扫描量热法（DSC）、氧化诱导时间（OIT）、热重分析（TGA）和拉伸试验，对含有25%、50%和75%PP的共混物，以及100%PP和原生PP进行了评估。结果表明，增加PP含量可提高聚合物在惰性条件下的流动性和热稳定性，但会显著降低抗氧化性和延展性。然而，25%PP共混物在性能和可回收性之间表现出良好的平衡，其弹性模量为PP的96%，屈服强度为PP的101%。与未挤出形式相比，通过挤出进行均质化处理可将回收PP的氧化稳定性提高22%。这些发现支持在原生PP中使用低至中等水平的PP，用于需要可预测和可调节性能的应用，有助于实现循环经济目标。
