Effect of environmental weathering on flexural creep behavior of long fiber-reinforced thermoplastic composites

Abstract

a b s t r a c tFlexural creep behavior of nylon 6/6 (NY66)e and polypropylene (PP)e based long fiber (l/d ¼ 2000À10 000) thermoplastic (LFT) composites was investigated as a function of ultraviolet irradiation and moisture absorption. Extrusion/compression-molded panels were prepared according to ASTM D-2990 and conditioned according to ASTM D-618. NY66 and PP LFTs were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier-transform infrared (FTIR) spectroscopy in the unexposed condition, and as-exposed to 253.7 nm UV radiation. The creep compliance of PP LFT increased with increasing UV exposure, whereas the creep compliance of NY66 LFT showed a moderate decrease with increasing UV exposure. Moisture absorption experiments were performed in boiling water until saturation on NY66 and its LFT composites. Characterization of desorbed moisture absorption specimens suggested slight variation in the structure, and an analysis of creep compliances showed minimal changes as compared to the dry/unexposed specimens.

A review of welding technologies for thermoplastic composites in aerospace applications

“…More recently, thermoplastic composites have found utilizaet al, 2011;Rezende et al, 2011;Chevali et al, 2010;Bates et al, 2009;Arici, 2007;Espert et al, 2004;Lee et al, 1993). A wide range of high performance thermoplastic matrices studied and reported.…”

Atmospheric corrosion of Nylon 6,6 in Mauritius

“…Figure 4 shows typical progressive surface colour change and degradation observed on the weathered samples' surfaces. Yellowing or discolouration is a common phenomenon observed during weathering of polymers [3].…”

“…Ultraviolet degradation, such as photo-oxidation. This involves the formation of micro cracks and a yellowing effect on composites [2] or surface cracking on long fiber-reinforced thermoplastic composites samples [3]; 3. Hydrolytic degradation, which can cause subsequent discolouration of the material [4]; 4.…”

“…Yellowing of the material is also a common parameter used to gauge quickly the degree of degradation due to U.V exposure. A study carried out by Chevali et al [3] showed that there was a significant increase in the yellowing effect of polypropylene (PP) with increasing exposure duration after 400 hours. 2.…”

Mechanical properties: wood lumber versus plastic lumber and thermoplastic composites

“…Nevertheless, in terms of durability and maintenance, studies have shown that plastic lumber provides a better performance than wood lumber (WINANDY;STARK;CLEMONS, 2004;GARCÍA et al, 2009;AZWA et al, 2013;NDIAYE;GUEYE;DIOP, 2013;WEI et al, 2013) and are also economically advantageous in the long term, as their maintenance can be performed less regularly and using simple products, such as soap and water. Plastic-based products also absorb less water (STARK, 2005;CHEVALI;DEAN;JANOWSKI, 2010;KORDKHEILI, 2011;BENTHIEN;THOEMEN, 2012;LEU et al, 2012;AZWA et al, 2013;CHAVOOSHI et al, 2014;YOUSSEF;EL-GENDY;KAMEL, 2015), which contributes to a longer useful life, as effects such as swelling (KLYOSOV, 2007), component buckling (KLYOSOV, 2007), decrease in mechanical strength (STARK, 2006;STRÖMBERG;KARLSSON, 2009;MORRELL et al, 2010;KORDKHEILI, 2011) and biological degradation (STRÖMBERG; KARLSSON, 2009;HEMMATI;GARMABI, 2012;NAUMANN;STEPHAN;NOLL, 2012;AZWA et al, 2013) are minimized. However, can they really substitute wood lumber products?…”