Impact of fillers (short glass fibers and rubber) on the hydrolysis-induced embrittlement of polyamide 6.6

Abstract

This study deals with the durability of composites based on polyamide 6.6 (PA6.6) in a humid environment, and more especially, with the loss of fracture properties. It is known that PA6.6 undergoes plasticization in the presence of water, but hydrolysis also occurs. This hydrolysis leads to a sharp decline in fracture properties in resin. The aim of this study is thus to understand the behavior of two PA6.6-based composites, one containing short glass fibers and the other both glass fibers and a rubber. The results showed the transition from ductile to brittle behavior as a function of hydrolysis time in resin. For composites, the drop in elongation breaking with the macromolecular chain length was linear for all ageing conditions considered here without marked transition. The results presented here can be used for lifetime prediction of PA6.6-based composites in a humid environment.

Relationships between molar mass and fracture properties of segmented urethane and amide copolymers modified by chemical degradation

“…The Dispersity Đ remains around 2 (not shown). These are evidences of a random scission mechanism, as reported in the literature in numerous cases: PP under oxidation, 17 polyethylene under oxidation, 28 polyamides under oxidation 29 and hydrolysis 30 or PLA under oxidation 31 . Random scission is thus the exclusive mechanism taking place.…”

Modelling pure polyamide 6 hydrolysis: Influence of water content in the amorphous phase

“…The hydrolysis of polyamide has been extensively studied in the literature [8,[10][11][12][13][14][15][16][17][18][19][20]. The degradation process is described as a chemical reaction between amide and water leading to the formation of acid and amine due to a chain scission process in the polymer.…”

MEG Effects on Hydrolysis of Polyamide 66/Glass Fiber Composites and Mechanical Property Changes

“…Py-GC/MS is widely used for qualitative and quantitative analyses of polymer composites and for obtaining information on molecular structures [ 50 ]. Hydroxyl groups are known to react and hydrolyze PA66 polar functional group (C=O, -NH) [ 21 , 22 ]. The pyrolysis byproducts of PA66 are cyclopentanone, hexamethylenediamine, and cyclic monomer [ 51 , 52 , 53 , 54 , 55 ].…”

“…PA66, which satisfies these requirements, should be developed. In fact, industrial studies aimed at developing such materials with hydrolysis resistance are ongoing [ 15 , 16 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Currently, several grades of hydrolysis resistant PA66/GF composites exist on the market; however, no direct scientific comparison of their hydrolysis resistance properties has been conducted, and no verification or correlation has been established between their degree of hydrolysis resistance and mechanical property changes.…”