Effect of Mixing Intensity on Foaming Behavior of LLDPE/HDPE Blends in Thermal Induced Batch Process

ABSTRACT

Linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) (with different shear thinning behaviors) were melt blended at two different compositions (10 and 25 wt%. of HDPE) and three different rotational speeds. Batch foaming process was performed over a wide range of temperatures. Bulk density measurement, cell structure evaluation, differential scanning calorimetry (DSC), and oscillatory rheology tests were performed. Results indicated the deterioration of foamability for those blended at the highest selected speed of 120 rpm. The blends mixed at a speed of 60 rpm, exhibited a slightly lower expansion ratio compared with those of mixed at a speed of 10 rpm with the same trend over the foaming temperature. For blends with 25 wt%. HDPE, proper cellular structures were obtained through a broader range of foaming temperature.

GRAPHICAL ABSTRACT

KEYWORDS:

• Batch foaming process
• differential scanning calorimetry
• mixing intensity
• polyethylene blends
• rheology