Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle

The main goal of this paper is the evaluation of the performances reversibility of hybrid composites when they are dried after being aged in salt-fog environment. To this aim, epoxy composites reinforced with flax and glass fabrics respectively in the internal and external laminae were at first exposed to salt-fog (i.e., identified as wet phase) and then stored in controlled conditions (i.e., identified as dry phase). The flexural properties evolution of these composites as well as their water uptake and contact angle were monitored at varying time of both phases. The flexural strength and modulus of hybrid composites is 23.4% (17.9%) and 15.5% (12.9%) lower than unaged ones after 30 (15) d…

MATERIALE ISOLANTE A BASE DI CACTACEE, PANNELLO REALIZZATO CON DETTO MATERIALE E RELATIVO PROCESSO DI PRODUZIONE

Si propone un pannello realizzato a partire dalla pianta opuntia ficus indica che opportunamente trattata, disidratata, macinata ed essiccata, viene assemblata con leganti e/o collanti. La novità è rappresentata dalla tipologia del materiale usato che fino ad oggi non ha avuto applicazione nel settore edilizio ed ha invece grandi potenzialità sia per la facilità di reperimento del materiale che costituisce una fonte di materia prima rinnovabile, sia per la grande disponibilità di materia prima sul territorio siciliano, sia per le buone prestazioni termo-acustiche che si sono raggiunte(λ 0.07). Si prevede di sviluppare una tecnologia che possa essere applicata in edilizia per coperture, sola…

Influence of anodizing surface treatment on the aging behavior in salt-fog environment of aluminum alloy 5083 to fiber reinforced composites adhesive joints

The present work aims to evaluate how an innovative and eco-friendly anodizing process with tartaric-sulfuric acid (TSA) bath and a pore widening in an aqueous solution of NaOH 0.1 M can improve the durability in marine environment of co-cured adhesive joints between an aluminum alloy (AA 5083) and fiber (i.e., glass or basalt)-reinforced composite substrates. The aging was carried out by exposing samples to salt-fog spray conditions (5 wt.% NaCl) for 30, 60 and 90 days in a climate chamber, in accordance with ASTM B117. In order to get further insights on the aging behaviour of bonded joints, neat matrix was also exposed to the same environment for 60 days. Quasi-static mechanical tests an…

Durability of flax-basalt hybrid composites for marine applications

The aim of the present work is to evaluate the influence of external layers of mat basalt on the durability behaviour and performances of flax/epoxy laminates. To this scope, long-term aging tests were performed to evaluate the durability of the two different laminates in critical environmental conditions. In particular, Flax composites were constituted by ten layers of bidirectional flax fabric whereas hybrid laminates (i.e. Flax-Basalt) were produced by replacing four external layers of bidirectional flax with four layers of basalt mat. Both laminates had a total average thickness equal to 3 mm. The samples were exposed to critical environmental conditions following the ASTM B 117 standar…

Caratterizzazione di pannelli sandwich al variare del materiale costituente il core

An experimental investigation on performances recovery of glass fiber reinforced composites exposed to a salt-fog/dry cycle

The main goal of this paper is the evaluation of the properties reversibility of glass fiber reinforced polymers (GFRPs) under discontinuous exposure to aggressive environmental conditions, typical of marine applications. To this aim, the GFRP manufactured through vacuum infusion process has been initially aged in humid conditions (i.e., exposure to salt-fog at 35 ◦C) for 15 and 30 days and then stored under controlled dry conditions (i.e., 50% R.H. and 23 ◦C) for times varying between 0 and 21 days. In order to evaluate the recover capability of this material, its water uptake has been monitored along the quasi-static flexural properties during the entire humid/dry cycle. Moreover, both 3D…

Specific Mechanical Properties of Glass/Carbon Epoxy Composites for Marine Applications

Mechanical behaviour of SPR/co-cured composite to aluminium joints

Effect of various moisture content on the mechanical and viscoelastic properties of giant reed Arundo donax L.

The giant reed Arundo donax L. is an aggressive grass widely diffused throughout warm temperate regions. Thanks to its remarkable features as fast-growing, eco friendly and high specific properties (i.e. high strength/weight and modulus/weight ratios), it is widely used in ancient and traditional buildings, especially in the realization of supports for roof cladding and paneling of walls. A better understanding and a consequent standardization of its properties could make it more suitable for general application in the sustainable building industry. Mechanical and viscoelastic properties of the giant reed were studied as a function of the moisture content. To this scope, various sets of ree…