Search results for "PMC"
showing 10 items of 42 documents
DEGRADATION OF MATER-BI /WOOD FLOUR BIOCOMPOSITES IN ACTIVE SEWAGE SLUDGE
2009
The mechanical properties of Mater-Bi® are, in general, not adequate for certain applications and the addition of a filler is therefore necessary. Among the different fillers, natural fibres are particularly interesting because they potentially allow improving the performance of the material without compromising its biodegradability. In order to improve the basic mechanical properties of a Mater-Bi grade and to obtain a new, fully biodegradable material, wood flour based composites were prepared by different processing methods. To simulate actual and not laboratory bacterial attack on the prepared materials, in this work we studied the biodegradation of the composites in a real active sewag…
Durability of Basalt/Hemp Hybrid Thermoplastic Composites
2019
The Achilles heel of thermoplastic natural fibre composites is their limited durability. The environmental degradation of the mechanical properties of hemp and hemp/basalt hybrid-reinforced high-density polyethylene (HDPE) composites has been investigated with a special focus on the effects of water ageing and accelerated ageing, including hygrothermal and UV radiation. Modification of the matrix was carried out using a maleic anhydride high-density polyethylene copolymer (MAPE) as a compatibilizer. Hybridization of hemp fibres with basalt fibres and the incorporation of MAPE were found to significantly decrease the water uptake (up to 75%) and increase the retention of mechanical propertie…
Properties evolution of flax/epoxy composites under fatigue loading
2014
International audience; The tension-tension fatigue behaviour of flax fibre reinforced epoxy matrix composites have been investigated for specimens having [0]12, [90]12, [0/90]3S and [±45]3S lay-ups. The Probabilized Stress-Number of cycles (P-S-N) curves have been determined for each laminate type. The measured stress and strain data allowed to quantify the evolution of the mechanical properties, i.e. stiffness, damping and permanent strain as a function of imposed cycles. Especially, the stiffening phenomenon of flax reinforcements oriented parallel to the loading direction has been confirmed. However, due to the competition between damage development and the fibre stiffening, the increas…
An experimental investigation on performances recovery of glass fiber reinforced composites exposed to a salt-fog/dry cycle
2023
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…
Durability behavior of bio-epoxy/jute-basalt hybrid composites for cladding
2016
The technology of dry assembly to produce multi-layer panels is an efficient alternative to traditional systems. Eco-sustainable systems are increasingly studied, particularly fiber reinforced composites for external cladding, based on natural fibers. However, the durability of these composites gives serious concern, in particular for their potential use in outdoor applications. To overcome this drawback, hybridization of natural fibers with mineral fibers as basalt ones appears promising. In this paper, the aging resistance of jute-reinforced laminate was compared with those of two hybrid laminates.
Wettability of flax/basalt reinforced composites during aging in salt spray conditions
2015
Aim of this work was to investigate the wettability of natural fibres reinforced epoxy composites, subjected to aging tests performed on two different laminates. The first laminate was constituted by stacking ten layers of bidirectional flax fabrics. The second one was produced by replacing two external flax layers with two layers of basalt mat, for each side of the laminate. Both laminates were exposed to salt-fog environmental conditions, according to ASTM B 117 standard, for 60 days. The results of wettability were compared with those of the water uptake test. Moreover, an analysis of variance was performed in order to evaluate the significance of the parameters that influence the wettab…
TOWARD A DESIGN METHOD FOR METAL-COMPOSITE CO-CURED JOINT BASED ON THE G-SIFs
2013
Abstract In this work, a systematic study of the singular stress field in the zone where the interface intersects the free edge surfaces of bonded metal-composite co-cured joints, has been performed. The obtained theoretical, numerical and experimental results have permitted to detect the relationships between the joint configuration and the singular stress field, as well as to implement a new design method based on the so called generalised stress intensity factors. Such a proposed method allows the user to predict the static strength of a generic metal-composite co-cured joint, vs. the main influence parameters as the elastic modulus of the coupled materials, the overlap length, the taper…
Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle
2022
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…
Modelling the structure-property relationships of high performance PBAT-based biocomposites with natural fibers obtained from Chamaerops humilis dwar…
2022
Two fibrous fillers were achieved from stalks and leaves of Chamaerops humilis dwarf palm and tested as reinforcing agents for poly(butylene adipate co-terephthalate) (PBAT)-based composites. The influence of filler type and content on the morphomechanical properties of the green composites was assessed. The outcomes of tensile tests pointed out that both fillers are strong candidates to overcome the two main limiting aspects of PBAT, that is, the lack of both stiffness and cost-effectiveness, while preserving its stretchability and environmental sustainability. The remarkable stiffness increments (up to 300%), combined with fair retention of stretchability (33%) and doubled resistance, led…
Mechanical behaviour of Mater-Bi/wood flour composites: a statistical approach
2008
Interest in biocomposites (lignocellulosic filled biopolymers) started in the 90s, due to environmental advantages, related to the full biodegradability of both matrix and filler, economical issues (organic fillers usually come from sawmill or agriculture wastes) and aesthetical issues (wood filled biopolymers could be particularly pleasant if used for indoor furnishing and automotive interior). In this work, a method for a systematic study of the properties of Mater-Bi®/wood flour composites is presented. A two-level full factorial model was built. It allows investigating the effects of multiple operative variables on the observed properties, their contributions, their optimal combinations…