Durability study of recycled glass-fiber-reinforced polyamide 66 in a service-related environment

Abstract

A study of the mechanical properties in an accelerated service-related environment of recycled glass-fiber-reinforced polyamide 66 is reported. Material reinforced with 30 wt % of short fibers was reground and remolded up to seven times. Thermal aging in air at 140ЊC for up to 3000 h and coolant aging at 110ЊC for up to 1000 h showed no significant differences in behavior pattern. In addition to mechanical testing, the fiber length measured directly and the matrix stability measured by differential scanning calorimetry (DSC) were used to determine the influence of process-induced degradation on the durability of recycled samples compared with that of virgin samples. The results indicate that fiber length controls the initial properties. The differences in tensile strength and modulus between recycled and virgin samples were similar within the examined times of aging and could be explained by process-induced fiber shortening. The onset of embrittlement during both aging conditions is revealed first in a decrease in tensile elongation at break. Because of a lower degree of fiber reinforcement, the elongation at break of recycled samples was always as good as that of virgin reference samples. However, increasing the number of molding operations up to four to five times resulted in a faster deterioration rate in elongation at break of recycled samples. Further processing had less effect on the deterioration rate. The oxidative stability of the matrix as determined by DSC decreased as a result of repeated processing. The results suggest that matrix stability is related to changes occurring in elongation at break during accelerated aging of samples remolded up to about four times.

Mechanical, chemical, thermal, and rheological properties of recycled PA6/ABS binary and PA6/PA66/ABS ternary blends

“…For PA6 polymer, a decrease of 28% in the tensile strength was found after 3 recycling process in the literature. 11 The decrease in the tensile strength with recycling was found for also PA66 15,33 and ABS 34 polymers.…”

“…The use of recycled plastic is one of the effective way to reduce the negative effect of plastic on environment. Some authors have investigated the effect of recycling on the mechanical, thermal and/or rheological properties of PA6, PA66, and ABS polymers. Virgin and recycled ABS/PA6 blends were prepared with the addition of the compatibilizer and a core‐shell rubber impact modifier .…”

The influence of recycling number on the mechanical, chemical, thermal and rheological properties of poly(butylene terephthalate)/polycarbonate binary blend and glass-fibre-reinforced composite

“…Another reason for the decrease in the tensile strength was due to the shortening of the length of the fibres after injection moulding processes. [28][29][30] The recycling process resulted in a decrement of 33.5% in the tensile strength of PBT/PC-GF composite after 5th recycling. However, for PBT/PC polymer blends, a very slight decrease in the tensile strength was found with the reprocessing cycle as compared to PBT/PC-GF composite.…”

Structural study and thermal behavior of composites: Polyamide 66/glass fibers: The reinforcement ratio effect on the kinetics of crystallization

“…These properties of the composite, are influenced by the mechanical strength of the interface (G/matrix). 2–8 And depend on the injection conditions such as design and molding temperature. 9–12 During the manufacture of short fibers, the decisive step in the process is the process of cooling including solidification.…”