Studies on blends of high‐density polyethylene and polypropylene produced by oscillating shear stress field

Abstract

ABSTRACT:Tensile strength and morphology of blends of high-density polyethylene (HDPE) and polypropylene (PP) obtained by oscillating packing injection molding were investigated via Universal Testing Machine, DSC, and SAXS. Tensile strength is greatly enhanced from 24.5 MPa to more than 90 MPa for pure HDPE and for blends with PP content less than 10 wt %. There exists a sharp decrease of tensile strength when PP content is more than 10 wt %. The shearinduced morphologies with core in the center, oriented zone surrounding the core and skin layer are observed in the cross-section areas of the samples. Interestingly, a sharp decrease of oriented zone is seen when PP content is more than 10 wt %, associated with the sharp decrease of tensile strength. DSC result shows double melting peaks with a high-temperature melting peak that is not present in the endotherm obtained from the central core and obtained from the samples by static packing injection molding, which indicates the existence of shish-kebab structure in the oriented zone. However, there is no difference of crystallinity between the samples by oscillating and by static packing injection molding. SAXS was used to analyze the complicated morphologies induced by shear stress, and results show that the crystal thickness could be greatly increased under shear stress.

A novel single-component composite based on phthalonitrile end-capped polyarylene ether nitrile: crystallization and crosslinking

“…Presently, considerable research activities and accompanying commercial interest are devoted to single-component composites, which are also referred to as self-reinforced composites or homocomposites [1][2][3][4][5][6][7]. The increasing interest in the singlecomponent composites is attributed to their unique advantages, such as the ideal recyclability and light weight, due to the absence of any fillers or dense reinforcing components [1,8].…”

Morphology and mechanical properties of poly(ethyleneoctene) copolymers obtained by dynamic packing injection molding

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Phthalonitrile end‐capped polyarylene ether nitrile: crystals embedded in matrix through crosslinking reaction

“…Nowadays, composites with low weight and recyclable properties attract considerable research interest since the demand for environmentally friendly products is constantly increasing. Compared to conventional composites whose reinforcement and matrix consist of different polymers, single‐component composites in which a polymer matrix is reinforced with oriented fibers, tapes or particles of the same polymer or of polymers belonging to the same type have attracted interest because of the absence of any filler or dense reinforcing components . Moreover, in these single‐component composites, the interfaces between composite components are potentially strong because they are chemically identical/compatible, resulting in superior mechanical properties of these single‐component composites …”