Origin of deterioration in mechanical properties of glass fiber reinforced nylon 6,6 composites by aqueous ethylene glycol solution

• Published in: Polymer composites Vol. 28; no. 6; pp. 778 - 784
• Main Authors: Hong, John Hee, Dhevi, D. Manjula, Lee, Jong Soon, Kim, Kap Jin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.12.2007; Willey; Blackwell Publishing Ltd
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers; Ethylene glycol; Fiber reinforced material; Mechanical properties; Tensile property; Chemical degradation; Experimental study; Mineral fiber; Composite material; Aqueous medium; Aliphatic polymer; Mechanical degradation; Glycolysis; Artificial ageing; Amide 66 polymer; Exposure time; Glass fiber
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.20351

Glass fiber reinforced nylon 6,6 (GFNY66) composites widely used for automotive applications undergo degradation when repeatedly exposed to aqueous ethylene glycol (EG) solution, resulting in significantly reduced mechanical properties. Hence, it is important to clearly understand the degradation and hydrogen bond breaking mechanism of nylon 6,6 (NY66) and interfacial failure mechanism in GFNY66 (when exposed to aqueous EG solution) in order to improve the mechanical properties of recycled NY66. From ATR‐IR spectra of NY66 immersed in aqueous EG solution at 108°C for varying intervals of time, the shifting of amide‐I band (νCO) at 1640 cm−1 towards lower frequency with increasing immersion time may be attributed to the breakage of intra‐ and intermolecular H‐bonding between amides in NY66 followed by the new formation of H‐bonding between amide group in NY66 and hydroxyl group in the absorbed EG. GPC data revealed the reduction in molecular weight due to the absorption of EG into NY66 matrix leading to chain scission of NY66. GFNY66 samples treated with aqueous EG solution exhibited pronounced deterioration in mechanical properties because of the interfacial failure between glass fiber and NY66 matrix as well as molecular weight reduction caused by the absorbed EG solution. POLYM. COMPOS., 28:778–784, 2007. © 2007 Society of Plastics Engineers