Reactive Extrusion Grafting of Glycidyl Methacrylate onto Low-Density and Recycled Polyethylene Using Supercritical Carbon Dioxide

Featured Application Authors are encouraged to provide a concise description of the specific application or a potential application of the work. This section is not mandatory. Glycidyl methacrylate (GMA) was grafted onto (recycled) polyethylene (PE) to design a new adhesive with better mechanical properties compared to non-grafted PE. The effects of the amount of GMA, the amount of dicumyl peroxide (DCP) and the use of supercritical carbon dioxide (scCO(2)) in a reactive extrusion (REX) were evaluated based on the grafting degree and efficiency of the grafted samples. Generally speaking, higher amounts of GMA led to higher functionalization degrees (FD), whereas higher amounts of DCP resulted in a lower FD due to the occurrence of more unfavorable side reactions. The influence of scCO(2) showed different outcomes for the two substrates used. Higher FDs were obtained for the low-density polyethylene (LDPE) samples while, by contrast, lower FDs were obtained for the recycled polyethylene (RPE) samples when using scCO(2). Additionally, adjusting the screw speed and the temperature profile of the extruder to the half-life time of the radical initiator appeared to have the highest positive impact on the FD. According to the tensile tests, all the grafted samples can withstand higher stress levels, especially the grafted RPE, compared to the non-grafted samples.

Automated summary

This study designed a new adhesive with better mechanical properties by grafting glycidyl methacrylate (GMA) onto (recycled) polyethylene (PE). The results showed that higher amounts of GMA led to higher functionalization degrees (FD), while higher amounts of dicumyl peroxide (DCP) resulted in lower FD due to more unfavorable side reactions. The influence of supercritical carbon dioxide (scCO(2)) on FD varied depending on the substrates used. Adjusting the screw speed and temperature profile had the highest positive impact on FD. All the grafted samples, especially the grafted RPE, showed higher stress levels compared to the non-grafted samples.