Use of postconsumer polyethylene in blends with polyamide 6: Effects of the extrusion method and the compatibilizer

Abstract

Blends of polyamide and high-density polyethylene show adequate properties for a large range of applications: they are used for the production of filaments, containers, and molding resins. The effect of the addition of 2 wt % of a compatibilizer, maleic anhydride grafted polyethylene, to the blend was studied and compared to the use of postconsumer polyethylene. The samples were extruded with single-and twin-screw extruders with 25, 50, or 75 wt % f polyethylene, and the test specimens, molded by injection, were characterized by stress-strain tests, thermal properties, and morphologies. Processing the blends with postconsumer polyethylene in both extruders improved the mechanical properties in comparison to the blends processed with highdensity polyethylene and the compatibilizer. The morphologies of these blends showed that there was a decrease in the domain size of the disperse phase with the use of the compatibilizer or postconsumer polyethylene. The results indicate that for this blend, postconsumer polyethylene substituted, with advantages, for the necessity of a compatibilizer and the use of the high-density polyethylene.

Polyaniline coated curauá fibres in polyamide-6 composites: the effect of fibre surface modification on the crystallographic properties

“…PA-6 accounts for a majority of the commercial production and application of polyamide [16]. Composites of polyamide-6 (PA-6) reinforced with curauá fibres were studied for the first time by Santos et al [6] aiming at glass fibre replacement.…”

Ultrasonic characterization of phase morphology of high density polyethylene/polyamide 6 blend melts

“…High density polyethylene (HDPE) and polyamide 6 (PA6) are semicrystalline plastics, which have versatile industrial applications. HDPE has excellent low temperature flexibility, low cost, and good resistance to moisture permeation [26], while PA6 shows high strength, favorable thermo‐mechanical characteristics, and good resistance to oxygen permeation and hydrocarbons [27]. Thus, it is conceivable that blends of HDPE and PA6 (HDPE/PA6) can synergically combine the merits of both components, provided that the blends are appropriately compatibilized and the corresponding phase morphology gets optimized.…”

In‐process ultrasonic measurements of orientation and disorientation relaxation of high‐density polyethylene/polyamide‐6 composites with compatibilizer

“…As one of the most commonly used general plastics, polyethylene (PE) has the advantages of low cost, light weight, nontoxicity, good chemical stability, and low moisture absorbance,6 and it is extensively applied to produce film, container, pipe, electric wire and cable, monofilament, and so on. On the other hand, polyamide (PA) is an engineering thermoplastic with high strength, wear resistance, and heat stability, and it is widely applied in automobile, electrical equipments, mechanical parts, as well as textile 7.…”

“…Because of the differences in molecular polarity and chain structure, PE/PA blends are thermodynamically immiscible, resulting in inferior performance of final products. A common and convenient method to improve the properties of PE/PA blends is the addition of a compatibilizer precursor (CP) 6, 12–20. It is recognized that the common mechanism is that a grafting reaction takes place between the epoxide or acidic functional groups of CP and the carboxyl/amine terminal groups of PA at PE–PA interface to in situ form a PE‐ g ‐PA copolymer, which generates a covalent bond between PE and PA 6, 12, 15.…”

“…As a result, the interfacial adhesion between the matrix and the dispersed phase is enhanced. Therefore, the addition of CP could result in a significant change in the morphology and properties of PE/PA composites, including the mechanical properties,6 rheological behaviors,12 thermal stability,6 melting and crystallization behaviors 16, 17, 21…”