Experimental and statistical study of the effect of temperature and waste ratio on the mechanical properties and cost of polystyrene polypropylene plastic blends

Abstract

Since most plastics are not biodegradable, plastic recycling is the main part of global efforts to reduce plastic in the waste stream. Sorting of plastics imposes lots of difficulties which can be avoided by introducing plastic blends. This paper starts by reviewing the recent attempts to study plastic blends. Accordingly, the purpose of this study is to analyze experimental results and apply statistical measures using ANOVA to study the effect of increasing the waste ratio that contains both waste polystyrene and polypropylene on the mechanical properties of pure polystyrene when injected at different temperatures. Cost is taken as a response factor to analyze whether the degradation of mechanical properties is justified by a decrease in cost. As expected, cost dramatically decreases with increasing the waste ratio at any temperature. Increasing the waste ratio resulted in better mechanical properties with a maximum at a 30% waste ratio at 200 C and 220 C. This paper ends with a multiobjective optimization analysis that helps decision-makers optimize the properties needed of the studied plastic blend by controlling both the temperature and waste ratio.

Upcycling Polystyrene

“…Insights into the behavior of waste plastic blends relating to their mechanical properties are essential to avoiding the plastic sorting stage. In Almishal et al, statistical measures (ANOVA) provided some insights into how the mechanical properties of pure PS are affected by an increased ratio of waste PS and PP injected at different temperatures [22]. The study found a dramatic decrease in cost with an increased PS/PP waste ratio at any temperature.…”

Towards Higher Quality of Recycled Plastics: Limitations from the Material’s Perspective

“…This confirms the trend of discussing plastic recycling in the context of the circular economy. For instance, the topics in 2020 associated with plastic recycling and circular economy mostly discussed the mechanical recycling process and the quality of mechanically recycled plastics [73][74][75][76][77][78], plastic waste flows and the associated environmental challenges [79][80][81], and challenges and solutions to the plastic waste recycling [82][83][84][85][86][87]. In this field, 86 reviewed research combining recycled plastic and additive manufacturing as a path towards a circular economy.…”

A creative form-finding tool: Deformation of plastic sheets due to the influence of temperature and gravity

“…This progressive weakening of mechanical properties is due to the intrinsic characteristics of polymeric materials because, as the temperature increases, the bonds within the material begin to vibrate with higher energy, leading to a reduction in intermolecular cohesion. 24 Consequently, the polymer sheet experiences a decrease in its mechanical strength, contributing to noticeable deformation of the material under its weight. Importantly, the decrease in mechanical properties is not uniform across the entire sheet: in regions with higher temperature, deformation occurs more prominently.…”