Deterioration in mechanical properties of glass fiber‐reinforced nylon 6,6 composites by aqueous calcium chloride mixture solutions

Abstract

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 Ca2+ 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 Ca2+ and Cl− ions absorbed by NY66 was calculated and found to follow its stoichiometric equivalence. GPC data exhibited less reduction in Mn and Mw 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···Ca2+ 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. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Controlled Surface Modification of Polyamide 6.6 Fibres Using CaCl2/H2O/EtOH Solutions

“…It can be observed that all spectra are very similar, showing characteristic peaks of PA 6.6. When CaCl 2 was removed by washing, decomplexation of the PA 6.6–CaCl 2 complex took place and the dissolved polymer was precipitated [ 23 ]. FTIR spectra in Figure 8 indicated that there were no changes in the chemical structure of PA 6.6. fibres.…”

“…Li et al used a mixture of CaCl 2 /EtOH to modify the surface properties of aromatic polyamide fibres (Kevlar), in order to improve the interfacial adhesion in fibre composites [ 21 ]. The integration of a Lewis acid into the polymer structure leads to modified crystallisation behaviours and therefore changes polymer properties [ 15 , 22 , 23 ].…”

Spatial Structure Investigation of Porous Shell Layer Formed by Swelling of PA66 Fibers in CaCl2/H2O/EtOH Mixtures

“…Further investigations showed that Ca 2+ absorption by PA66 increases with time but does not degrade the polymer. 14 The interaction proceeds through Lewis acid−base complexation between CaCl 2 and the carbonyl groups (CO) in polyamides, and a similar mode of interaction is also observed with GaCl 3 and AlCl 3 . 15−17 The Ca 2+ complexation with polyamide suppresses the hydrogen bond formation between the polymer chains, and this effect has been employed to help increase the draw ratio in fiber spinning, by adding the salt to polymer melts and solutions.…”

“…They observed that aqueous CaCl 2 solutions caused stress cracking of the polymer and that the salt is partially soluble in the polymer. Further investigations showed that Ca 2+ absorption by PA66 increases with time but does not degrade the polymer . The interaction proceeds through Lewis acid–base complexation between CaCl 2 and the carbonyl groups (CO) in polyamides, and a similar mode of interaction is also observed with GaCl 3 and AlCl 3 . − The Ca 2+ complexation with polyamide suppresses the hydrogen bond formation between the polymer chains, and this effect has been employed to help increase the draw ratio in fiber spinning, by adding the salt to polymer melts and solutions. − Moreover, the decomplexation process of PA6/CaCl 2 in different nonsolvents was investigated by Liu et al, and it was found that depending on the nonsolvent, different crystalline forms are obtained .…”

A non-destructive, environment-friendly method for separating and recycling polyamide 6 from waste and scrap polyamide 6 blended textiles

“…This is because the higher stirring speed increased the contact between Was PA6 textiles and the solvents. 27,31,32 In addition, the quick shedding of dissolved PA6 enhanced this contact and, thus, the dissolution of Was PA6 textiles. However, when the stirring speed reached a certain level (at 300 r/min), the rising recovery rate was not immediately apparent.…”