MECHANICAL INTERGRITY OF HDPE BUTT FUSION JOINTS – EFFECT OF CARBON BLACK DISTRIBUTION

Maret 7, 2022 by admin in Industry News

Suleyman Deveci, Nisha Preschilla, Sulistiyanto Nugroho, Birkan Eryigit

# 2021 Amsterdam

Carbon black (CB) has been used as a perfect and the cheapest solution to prevent photo degradation of polyethylene against UV light exposure. The effect of carbon black on the mechanical properties of polyethylene pipes was studied extensively, but only on well dispersed and distributed carbon black polyethylene composites. As a continuation of the previous work presented at PPXIX Las Vegas in 2018 [1], the effect of carbon black distribution on the mechanical properties of butt- fusion joints was investigated in this current work. Polyethylene pipes with similar carbon black concentrations but different distributions were produced with industrial scale compounding and extrusion equipment. Waisted tensile test specimens were milled out directly from the butt-fused pipe samples and elongated to fracture at fusion zone. Carbon black distributions at the butt fusion interphase, both in axial and radial directions, were investigated. A significant decrease in joint integrity, measured as work of fracture, was observed for the welds made with polyethylene pipes with inhomogeneous carbon black distributions. It was found that the width of areas that do not contain carbon black (windows) can significantly enlarge at the butt fusion interphase due to shearing, resulting in brittle failures at the butt fusion interphase with a magnitude related to the level of inhomogeneity. This work focuses on the evaluation of fracture surfaces of weld interphases and their relationship with the level of carbon black inhomogeneity in the polyethylene matrix.

article source : https://www.pe100plus.com/PPCA/MECHANICAL-INTERGRITY-OF-HDPE-BUTT-FUSION-JOINTS-EFFECT-OF-CARBON-BLACK-DISTRIBUTION-p1756.html