In the quest for sustainable manufacturing, researchers are delving deep into the recycling of plastics, particularly low-density polyethylene (LDPE), a material ubiquitous in extrusion blow molding (EBM). A recent study published in *Materials Research Express* (translated from Malay as “Materials Research Express”) sheds light on how recycled and re-recycled LDPE (rLDPE and rrLDPE) impact the properties of LDPE blends, offering crucial insights for the energy and manufacturing sectors.
Led by Cee Kee Lim from the Faculty of Chemical Engineering & Technology at Universiti Malaysia Perlis (UniMAP), the research explores the delicate balance between sustainability and material performance. “Understanding the degradation mechanisms and property retention of LDPE blends is essential for upholding product quality while advancing sustainability,” Lim explains. The study investigates how multiple reprocessing cycles and blending affect the physical, flow behavior, mechanical, structural, and thermal properties of LDPE.
The findings reveal that as the recycled content increases, so do moisture content and density, primarily due to oxidation. The melt flow index (MFI) also rises, indicating a reduction in molecular weight. However, the trade-off is a decline in both tensile and impact strength. “Blends with ≤30 wt% rLDPE maintained acceptable performance, while rrLDPE content exceeding 10 wt% led to significant deterioration,” Lim notes.
The research employs advanced techniques such as Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) to verify oxidative alterations and reductions in crystallinity. FTIR analysis confirmed increased hydroxyl (-OH) and carbonyl (C=O) functional groups, while DSC results showed a reduction in crystallinity from 49.17% (virgin LDPE) to 34.23% (re-recycled LDPE), underscoring structural degradation.
For the energy and manufacturing sectors, these insights are invaluable. As the demand for sustainable practices grows, understanding the limits of recycled materials is crucial for maintaining product integrity. “This research provides a roadmap for optimizing sustainable LDPE formulations, balancing environmental benefits with material integrity,” Lim adds.
The study’s implications extend beyond immediate applications, offering a glimpse into future developments in polymer recycling and sustainable manufacturing. By optimizing the use of recycled and re-recycled LDPE, industries can reduce waste and conserve non-renewable resources without compromising on quality. As the world moves towards a circular economy, such research paves the way for innovative solutions that harmonize environmental stewardship with industrial efficiency.
In the broader context, this research underscores the importance of interdisciplinary collaboration and continuous innovation in the field of materials science. As Lim and his team continue to explore the frontiers of sustainable manufacturing, their work serves as a beacon for industries seeking to balance progress with responsibility.