scholarly journals Fibre Individualisation and Mechanical Properties of a Flax-PLA Non-Woven Composite Following Physical Pre-Treatments

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 846
Author(s):  
Maxime Gautreau ◽  
Antoine Kervoelen ◽  
Guillaume Barteau ◽  
François Delattre ◽  
Thibaut Colinart ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gamma Irradiation ◽  
Woven Composites ◽  
Environmental Benefit ◽  
Desorption Hysteresis ◽  
Moderate Difference ◽  
Chemical Products ◽  
Pre Treatment ◽  
Harmful Effects ◽  
Fibre Matrix

Pre-treatments for plant fibres are very popular for increasing the fineness of bundles, promoting individualisation of fibres, modifying the fibre-matrix interface or reducing water uptake. Most pre-treatments are based on the use of chemicals and raise concerns about possible harmful effects on the environment. In this study, we used physical pre-treatments without the addition of chemical products. Flax tows were subjected to ultrasound and gamma irradiation to increase the number of elementary fibres. For gamma pre-treatments, a 20% increase in the number of elementary fibres was quantified. The biochemical composition of pre-treated flax tows exhibited a partial elimination of sugars related to pectin and hemicelluloses depending on the pre-treatment. The hygroscopic behaviour showed a comparable decreasing trend for water sorption-desorption hysteresis for both types of pre-treatment. Then, non-woven composites were produced from the pre-treated tows using poly-(lactid) (PLA) as a bio-based matrix. A moderate difference between the composite mechanical properties was generally demonstrated, with a significant increase in the stress at break observed for the case of ultrasound pre-treatment. Finally, an environmental analysis was carried out and discussed to quantitatively compare the different environmental impacts of the pre-treatments for composite applications; the environmental benefit of using gamma irradiation compared to ultrasound pre-treatment was demonstrated.

Research Advance in Harmful Effects and Removal of Impurity Fe from Al and Al Alloys

2011 ◽  
Vol 295-297 ◽  
pp. 751-759 ◽  
Author(s):  
Hua Shen ◽  
Wei Dong Yang ◽  
He Liang ◽  
Guang Chun Yao
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Pure Aluminum ◽  
Al Alloys ◽  
Precipitation Method ◽  
Filtration Method ◽  
Purification Methods ◽  
Research Advance ◽  
Harmful Effects

The presence of Fe and harmful effects on mechanical properties of pure aluminum and aluminum alloys are introduced. Several purification methods are reviewed, but all of them are of definite limitations. It is effective that precipitation method, filtration method and centrifugal division method are integrated.

scholarly journals A Review on Mechanical Properties of Natural Fibre Reinforced Polymer Composites under Various Strain Rates

2021 ◽  
Vol 5 (5) ◽  
pp. 130
Author(s):  
Tan Ke Khieng ◽  
Sujan Debnath ◽  
Ernest Ting Chaw Liang ◽  
Mahmood Anwar ◽  
Alokesh Pramanik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Polymer Composites ◽  
Stress Transfer ◽  
Natural Fibre ◽  
Transfer Efficiency ◽  
Strain Rates ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Fibre Matrix

With the lightning speed of technological evolution, the demand for high performance yet sustainable natural fibres reinforced polymer composites (NFPCs) are rising. Especially a mechanically competent NFPCs under various loading conditions are growing day by day. However, the polymers mechanical properties are strain-rate dependent due to their viscoelastic nature. Especially for natural fibre reinforced polymer composites (NFPCs) which the involvement of filler has caused rather complex failure mechanisms under different strain rates. Moreover, some uneven micro-sized natural fibres such as bagasse, coir and wood were found often resulting in micro-cracks and voids formation in composites. This paper provides an overview of recent research on the mechanical properties of NFPCs under various loading conditions-different form (tensile, compression, bending) and different strain rates. The literature on characterisation techniques toward different strain rates, composite failure behaviours and current challenges are summarised which have led to the notion of future study trend. The strength of NFPCs is generally found grow proportionally with the strain rate up to a certain degree depending on the fibre-matrix stress-transfer efficiency. The failure modes such as embrittlement and fibre-matrix debonding were often encountered at higher strain rates. The natural filler properties, amount, sizes and polymer matrix types are found to be few key factors affecting the performances of composites under various strain rates whereby optimally adjust these factors could maximise the fibre-matrix stress-transfer efficiency and led to performance increases under various loading strain rates.

scholarly journals Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1242
Author(s):  
Olga Mysiukiewicz ◽  
Paulina Kosmela ◽  
Mateusz Barczewski ◽  
Aleksander Hejna
Keyword(s):  
Mechanical Properties ◽  
Melt Flow Index ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Flow Index ◽  
Scanning Calorimetry ◽  
Metal Composites ◽  
Pre Treatment ◽  
The Impact ◽  
Properties Of Composites

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.

scholarly journals Dynamic Response of Thermally Bonded Bicomponent Fibre Nonwovens

2011 ◽  
Vol 70 ◽  
pp. 405-409 ◽  
Author(s):  
Emrah Demirci ◽  
Memiş Acar ◽  
Behnam Pourdeyhimi ◽  
Vadim V. Silberschmidt
Keyword(s):  
Mechanical Properties ◽  
Dynamic Response ◽  
Fibre Diameter ◽  
Orientation Distribution ◽  
Nonwoven Fabric ◽  
Woven Fabrics ◽  
Core Material ◽  
Finite Element Software ◽  
Anisotropic Mechanical Properties ◽  
Fibre Matrix

Having a unique microstructure, nonwoven fabrics possess distinct mechanical properties, dissimilar to those of woven fabrics and composites. This paper aims to introduce a methodology for simulating a dynamic response of core/sheath-type thermally bonded bicomponent fibre nonwovens. The simulated nonwoven fabric is treated as an assembly of two regions with distinct mechanical properties. One region - the fibre matrix – is composed of non-uniformly oriented core/sheath fibres acting as link between bond points. Non-uniform orientation of individual fibres is introduced into the model in terms of the orientation distribution function in order to calculate the structure’s anisotropy. Another region – bond points – is treated in simulations as a deformable bicomponent composite material, composed of the sheath material as its matrix and the core material as reinforcing fibres with random orientations. Time-dependent anisotropic mechanical properties of these regions are assessed based on fibre characteristics and manufacturing parameters such as the planar density, core/sheath ratio, fibre diameter etc. Having distinct anisotropic mechanical properties for two regions, dynamic response of the fabric is modelled in the finite element software with shell elements with thicknesses identical to those of the bond points and fibre matrix.

Synergetic effect of freeze-drying and gamma irradiation on the mechanical properties of human cancellous bone

2010 ◽  
Vol 12 (4) ◽  
pp. 281-288 ◽  
Author(s):  
Olivier Cornu ◽  
Jérome Boquet ◽  
Olivier Nonclercq ◽  
Pierre-Louis Docquier ◽  
John Van Tomme ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gamma Irradiation ◽  
Cancellous Bone ◽  
Freeze Drying ◽  
Synergetic Effect ◽  
Human Cancellous Bone

Plasma Surface Treatment: Effects on Mechanical and Corrosion Protection Properties of Hybrid Sol–Gel Coatings

2019 ◽  
Author(s):  
R. Subasri
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Surface Treatment ◽  
Corrosion Protection ◽  
Sol Gel ◽  
Surface Cleaning ◽  
Al Alloys ◽  
Plasma Surface ◽  
Wet Chemical ◽  
Pre Treatment

Surface cleaning and activation of substrates are two critical processes that affect the mechanical and corrosion resistance properties of protective coatings when deposited on the substrates. Surface cleaning removes the contaminants, for example, grease on the substrate, and surface activation introduces active bonds on the substrate thereby increasing the surface free energy. Conventionally, surface cleaning and activation of aluminum and its alloys are carried out by a wet chemical technique. A convenient and safe alternate to the wet chemical cleaning/activation would be to use plasma for the same purpose. Plasma surface pre-treatment greatly improves adhesion of coatings deposited, which is very vital for good corrosion protection and mechanical properties such as scratch and abrasion resistance. Cold and atmospheric air plasma treatments have been the most widely studied pre-treatments for Al alloys. This article will discuss the advancements in the use of plasma treatment on Al/Al alloys and its effect on corrosion resistance and mechanical properties of coatings deposited after the surface treatment.

scholarly journals Influence of layering pattern of modified kenaf fiber on thermomechanical properties of epoxy composites

2019 ◽  
Vol 36 (1) ◽  
pp. 47-62
Author(s):  
AR Mohammed ◽  
MS Nurul Atiqah ◽  
Deepu A Gopakumar ◽  
MR Fazita ◽  
Samsul Rizal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Modification ◽  
Epoxy Matrix ◽  
Epoxy Composites ◽  
Woven Composites ◽  
Fiber Reinforced ◽  
Kenaf Fiber ◽  
Kenaf Fibers ◽  
The Impact ◽  
Woven Kenaf

Natural fiber-reinforced composites gained considerable interest in the scientific community due to their eco-friendly nature, cost-effective, and excellent mechanical properties. Here, we reported a chemical modification of kenaf fiber using propionic anhydride to enhance the compatibility with the epoxy matrix. The incorporation of the modified woven and nonwoven kenaf fibers into the epoxy matrix resulted in the improvement of the thermal and mechanical properties of the composite. The thermal stability of the epoxy composites was enhanced from 403°C to 677°C by incorporating modified woven kenaf fibers into the epoxy matrix. The modified and unmodified woven kenaf fiber-reinforced epoxy composites had a tensile strength of 64.11 and 58.82 MPa, respectively. The modified woven composites had highest flexural strength, which was 89.4 MPa, whereas, for unmodified composites, it was 86.8 MPa. The modified woven fiber-reinforced epoxy composites showed the highest value of flexural modulus, which was 6.0 GPa compared to unmodified woven composites (5.51 GPa). The impact strength of the epoxy composites was enhanced to 9.43 kJ m−2 by the incarnation of modified woven kenaf fibers into epoxy matrix. This study will be an effective platform to design the chemical modification strategy on natural fibers for enhancing the compatibility toward the hydrophobic polymer matrices.

scholarly journals Influence of Furfuryl Alcohol Fiber Pre-Treatment on the Moisture Absorption and Mechanical Properties of Flax Fiber Composites

Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 59 ◽  
Author(s):  
Yunlong Jia ◽  
Bodo Fiedler
Keyword(s):  
Mechanical Properties ◽  
Furfuryl Alcohol ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Tensile Tests ◽  
Fiber Composites ◽  
Flax Fiber ◽  
Moisture Resistance ◽  
Structural Applications ◽  
Pre Treatment

Poor moisture resistance of natural fiber reinforced bio-composites is a major concern in structural applications. Many efforts have been devoted to alleviate degradation of bio-composites caused by moisture absorption. Among them, fiber pre-treatment has been proven to be effective. This paper proposes an alternative “green” fiber pretreatment with furfuryl alcohol. Pre-treatments with different parameters were performed and the influence on the mechanical properties of fiber bundles and composites was investigated. Moisture resistance of composites was evaluated by water absorption tests. Mechanical properties of composites with different water contents were analyzed in tensile tests. The results show that furfuryl alcohol pretreatment is a promising method to improve moisture resistance and mechanical properties (e.g., Young’s modulus increases up to 18%) of flax fiber composites.

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