Deterioration in Mechanical Properties of Glass Fiber-Reinforced Nylon 6,6 Composites by Aqueous Calcium Chloride Mixture Solutions

摘要

In this article, nylon 6,6 (NY66) and glass fiber-(30 wt%) reinforced NY66 (GFNY66) specimens were immersed in various aqueous calcium chloride (aq. CaCl2) mixture solutions at different thermal conditions for varying intervals of time, and analyzed using attenuated total reflection-infrared (ATR-IR) spectroscopy, inductively coupled plasma (ICP), energy dispersive X-ray (EDX), gel permeation chromatography (GPC), and mechanical studies. ICP data revealed increasing concentration of absorbed Ca~(2+) ions with increasing immersion time resulting in disruption of intra- and intermolecular H-bonding as confirmed using ATR-IR results. From EDX data, the ratio of Ca~(2+) and Cl~- ions absorbed by NY66 was calculated and found to follow its stoichiometric equivalence. GPC data exhibited less reduction in M_n and M_m for aq. CaCl2-treated NY66 specimens suggesting the absence of any significant chemical degradation, but the occurrence of only physical changes involving H-bond breakage and the formation of new C=O···Ca~(2+) dative bond in NY66 matrix. The mechanical properties of GFNY66 samples treated with various types of aq. CaCl2 solutions exhibited pronounced deterioration, possibly due to the interfacial failure between glass fiber and NY66 matrix. The results obtained from this study were quite useful toward understanding the degradation mechanism in NY66 and GFNY66 caused by various aq. CaCl2 mixture solutions, and will be helpful in improving the mechanical properties of recycled NY66.