Polymer Foams Waste Management: A Focus on Mechanical and Chemical Recycling

Shojaei, Sahar; Rostami-Tapeh-Esmaeil, Ehsan; Rodrigue, Denis

doi:10.1021/bk-2023-1440.ch014

Cited by 3 publications

(1 citation statement)

References 116 publications

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“…The general recyclability of the most common polymer foams has been investigated in various studies. For example, Shojaei et al presented several studies that focused on the recycling of polyurethane foam either by mechanical or chemical recycling [14]. However, the recycling of particle foams has been investigated far less frequently.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Recycled Expanded Polyamide Beads through Artificial Ageing and Mechanical Recycling as a Proof of Concept for Circular Economy

Handtke,

Brömstrup,

Hain

et al. 2024

Polymers

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Car manufacturers are currently challenged with increasing the sustainability of their products and production to comply with sustainability requirements and legislation. One way to enhance product sustainability is by reducing the carbon footprint of fossil-based plastic parts. Particle foams are a promising solution to achieve the goal of using lightweight parts with minimal material input. Ongoing developments involve the use of expanded particle foam beads made from engineering plastics such as polyamide (EPA). To achieve this, a simulated life cycle was carried out on virgin EPA, including mechanical recycling. The virgin material was processed into specimens using a steam-free method. One series was artificially aged to replicate automotive life cycle stresses, while the other series was not. The mechanical recycling and re-foaming of the minipellets were then carried out, resulting in an EPA particle foam with 100% recycled content. Finally, the thermal and chemical material properties were comparatively analysed. The study shows that the recycled EPA beads underwent polymer degradation during the simulated life cycle, as evidenced by their material properties. For instance, the recycled beads showed a more heterogeneous molecular weight distribution (an increase in PDI from two to three), contained carbonyl groups, and exhibited an increase in the degree of crystallization from approximately 24% to 36%.

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Section: Introductionmentioning

confidence: 99%

Investigation of Recycled Expanded Polyamide Beads through Artificial Ageing and Mechanical Recycling as a Proof of Concept for Circular Economy

Handtke,

Brömstrup,

Hain

et al. 2024

Polymers

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Recycled silica as a renewable and sustainable alternative to carbon black in natural rubber foams

Rostami‐Tapeh‐Esmaeil

Kazemi

Ahmad

et al. 2023

Polymer International

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Sustainable natural rubber foams were prepared by replacing petroleum‐based carbon black (CB) with recycled silica (SiO2) nanoparticles. The total nanofiller concentration was fixed at 40 phr, while the CB/silica ratio was changed from 40/0 to 0/40. The results showed that increasing the silica content increased the curing characteristics, such as delta torque (ΔM) by 54%, scorch time (ts) by 50% and optimum curing time (t90) by 65%. But foams based on a hybrid system (20/20) produced a more homogeneous structure improving the cell nucleation step and leading to the smallest cell size (18 μm) and highest cell density (8.8 × 103 cells mm−3) due to reduced filler−filler interactions and better particle dispersion. This improved cellular morphology generated superior mechanical and thermal insulation performance, including the highest compression modulus (2.7 MPa), compressive strength (1.9 MPa) and recoverability (96.6%) combined with the lowest thermal conductivity (0.114 W m−1 K−1) at a density of 0.652 g cm−3. Nevertheless, the foam with 40 phr silica showed higher compressive modulus (26%) and compression strength (15%) compared to the reference sample having 40 phr CB, mainly due to its higher crosslink density. As a final comparison, the recycled silica, being a suitable and sustainable alternative to petroleum‐based CB, showed superior mechanical and thermal insulation properties compared to a commercial grade of silica for natural rubber foams. © 2023 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

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Optimization of natural rubber foams: Effect of foaming agent content and processing conditions on the cellular structure and mechanical properties

Rostami-Tapeh-Esmaeil,

Ahmad,

Kazemi

et al. 2024

Cellular Polymers

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In the past decades, natural rubber (NR) foams became popular in the automotive, construction and aerospace industries because of their lightweight, flexibility and shock-absorbing properties. The selection of optimal formulation and processing parameters is critical to produce foam with specific properties depending on the application. In this study, the effect of foaming agent concentration, foaming temperature and time on the morphological and mechanical properties of NR foams was investigated. First, increasing the foaming agent content from 5 to 9 phr (parts per hundred rubber) increased the cell size (16%), while decreasing the compression modulus (28%). In the second part, increasing the foaming temperature (145 to 155°C) resulted in larger cell size (163%); while decreasing the cell density (28%), compression modulus (2%), and hardness (1%). In the third part, increasing the foaming time (25 to 45 min) led to smaller cell size (63%) combined with higher cell density (100%), compression modulus (16%), and hardness (3%). Based on all the results obtained, the best NR foam was obtained with 7 phr of foaming agent and produced at 150°C for 35 min leading to superior morphological and mechanical performance: the smallest cell size (25 µm) and the most uniform cell size distribution ( Đ = 1.03) generating the highest compression modulus (3.36 MPa). Finally, the experimental compression results were combined to build a nonlinear regression model to optimize the formulation and processing conditions leading to 6.5 phr of OBSH molded at 150°C for 36 min. The model showed good agreement with a validation test with less than 2% deviation observed for both compression modulus and strength.

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Polymer Foams Waste Management: A Focus on Mechanical and Chemical Recycling

Cited by 3 publications

References 116 publications

Investigation of Recycled Expanded Polyamide Beads through Artificial Ageing and Mechanical Recycling as a Proof of Concept for Circular Economy

Investigation of Recycled Expanded Polyamide Beads through Artificial Ageing and Mechanical Recycling as a Proof of Concept for Circular Economy

Recycled silica as a renewable and sustainable alternative to carbon black in natural rubber foams

Optimization of natural rubber foams: Effect of foaming agent content and processing conditions on the cellular structure and mechanical properties

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