Fabrication of high-performance HDPE/CWPF blend film via the assistance of OBC and solid-state drawing

Abstract

To achieving highly efficient reuse of commingled waste plastic films (CWPF) in high-density polyethylene (HDPE), elastomer-olefin block copolymer (OBC) was adopted to improve the compatibility between CWPF and HDPE, and solid-state drawing was further used to improve the mechanical properties of the blends. The results showed that OBC could form core-shell structure with CWPF, as a bridge layer to simultaneously connect CWPF and HDPE, and form epitaxial crystallization induced by HDPE crystals, thereby greatly enhancing the compatibility between CWPF and HDPE, and improving the tensile strength, elongation at break and impact strength of HDPE/CWPF blend. In the subsequent solid-state drawing, depending on the fluidity of OBC at the drawing temperature of 100 °C, more CWPF were covered, efficiently reducing the defects caused by CWPF along the transverse direction (TD) and increasing the elongation at break of the stretched sheet along this direction. With the increase of draw ratio, lamellae in fibril along TD and shish-kebab-like structure along the flow direction (FD) formed, greatly improving the tensile strength of the blend along both TD and FD. And the long period (Lp), amorphous region (La) and lateral dimension (Llateral) decreased, but lamella thickness (Lc) increased. This work provides good bases for obtaining novel and low-cost HDPE based material as well as high-effect recycling of CWPF.