In this paper, low density polyethylene (LDPE) was exposed to forty (40) consecutive extrusion cycles to simulate the process of scrap mechanical recycling. The evolution of thermal, rheological, as well as, time-dependent mechanical properties accompanying the gradual degradation of the recycled polymers were monitored and evaluated by means of DSC, rheological measurement and creep measurement. The results show that simulated 40 recycling cycles did not significantly change the measured extrusion parameters, thermal properties and time-dependent mechanical properties of LDPE. However, there was notable change in LDPE rheological properties after repeated extrusion. Investigated rheological properties of recycled materials suggest that gelation and thermal degradation of LDPE occur after repeated extrusion.
COBISS.SI-ID: 12008987
In this work it has been shown that macroscopic properties of POM are sensitive to the addition of short polymeric chains, particularly in the molten state. For instance, bimodal POM which has a higher content of short chains than monomodal POM shows a much lower viscosity. The addition of compatible wax further increases the content of short chains and as a result the viscosity decreases even more, without a large change in creep behavior or thermal properties. An increased flowability is extremely important to the mold filling process during powder injection molding (PIM). Thus, the modified bimodal POM can potentially be used as binder for PIM feedstock.
COBISS.SI-ID: 12023067