Preparation of crosslinkable high density polyethylene and polypropylene polyblends

Koltuksuz, Barış
High density polyethylene (HDPE) and polypropylene (PP) are two commonly used thermoplastic polymers existing in the commodity plastic market due to their developed and easy post-reactor processability characteristics. Although these two polymers can be subjected to reprocessing, they eventually experience critical losses in their main physical and mechanical properties at elevated temperatures. With the aim of preventing these losses in their mechanical and thermal properties in their individual and blended states, this thesis presents a unique way of processing the blends of the sought polymer components incorporated with dicumyl peroxide (DCP). The two polymers were extruded with weight percentages of 30%, 50%, and 70% for each polymer. Followed by the swelling of the pellets in hexane-DCP solution, they were processed into films in a hot-press. The data obtained as a result of tensile testing performed on the specimens taken from the prepared films showed that the Young’s moduli of individual PP set incorporated with 1.0% (w/w) DCP, 30HDPE70PP set incorporated with 0.5% (w/w) DCP, and 50HDPE50PP set incorporated with 0.5% (w/w) DCP were increased by 28.5%, 28.4%, and 2.45% compared to their pristine values, respectively. The tensile strength of 30HDPE70PP set at 2.0% (w/w) DCP level experienced a small increase. The percentage elongation of 70HDPE30PP set was increased from its pristine value of 8% to 30%, 44%, and 98% with addition of 0.5% (w/w), 1.0% (w/w) and 2.0% (w/w) DCP, respectively. Upon processing the blends with DCP and applying differential scanning calorimetry (DSC) analysis to their specimens, their percent crystallinities were calculated from the analysis outputs. The mechanical results are mutually explained via the simultaneous interpretation of the calorimetric analysis data.


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Citation Formats
B. Koltuksuz, “Preparation of crosslinkable high density polyethylene and polypropylene polyblends,” M.S. - Master of Science, Middle East Technical University, 2015.