Fiber-Matrix Relationship for Composites Preparation

Shesan, Owonubi J.; Stephen, Agwuncha C.; Chioma, Anusionwu G.; Neerish, Revaprasadu; Rotimi, Sadiku E.

doi:10.5772/intechopen.84753

Cited by 38 publications

(23 citation statements)

References 179 publications

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“…It is worth mentioning that Young’s modulus of the natural fibre is also dependent on the fibre weight ratio: it increases when the fibre weight ratio raises to a maximum value; after that, it decreases. 51…”

Section: Resultsmentioning

confidence: 99%

Physical and mechanical properties of polyurethane thermoset matrices reinforced with green coconut fibres

Faria

Júnior

Resende

et al. 2020

Journal of Composite Materials

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Currently, the use of composites to replace parts made only with plastics has been gradually employed. The advantages of these composites are low cost, high availability of raw materials and good physical and mechanical properties. Thus, this work aimed at producing and characterizing composites produced with coconut fibre reinforced polyurethane matrices. The coconut fibres were studied as to their chemical constituents, aspect ratio, bulk density, pH, tensile properties, and surface SEM images. The composites were prepared using the hand lay-up process and four different concentrations of coconut fibre were evaluated: 30, 40, 50, and 60%. The composites were assessed as for water absorption after 20 days of immersion, bulk density, impact IZOD, tensile tests, and visualize the matrix-reinforcement interface using SEM. The electron micrographs showed a great deal of impurities on the surface of coconut fibres, such as greases, waxes, and gums, due to the high amount of extraction material (19.78%), which damages the adherence of the polymer onto the coconut fibre and, as observed, cause detachment between the reinforcement and the matrix. The tensile strength of the composites tended to increase as greater amounts of coconut fibres were added to the matrix. The averages were around 6.51 to 6.72 MPa for composites with 30 and 60% fibres, respectively. Therefore, coconut fibres can be considered as an alternative to synthetic fibres commonly used in composites, and they can be used at a ratio of 60% without prejudicing the properties of the composites, making them lighter and cheaper.

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Section: Resultsmentioning

confidence: 99%

Physical and mechanical properties of polyurethane thermoset matrices reinforced with green coconut fibres

Faria

Júnior

Resende

et al. 2020

Journal of Composite Materials

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“…In fact, Arrieta et al [ 40 ] proposed a molecular interaction between the hydroxyl groups of cellulose and the carbonyl groups of the PLA, referred to as hydrogen bonding. This aspect could contribute to the increase in the interfacial interaction fiber/matrix, which is considered to be mainly responsible for the mechanical features in a composite system, and for the superior ability of the transferring load from the polymer to the reinforcement [ 45 ]. In fact, the Young modulus increased by approximately 100% and the tensile strength gained an augment of 57% compared to the features of the compounds containing the highest amount of tested cellulose (77 vol.%) with that of the pure polymer.…”

Section: Discussionmentioning

confidence: 99%

Influence of the Processing Conditions on the Mechanical Performance of Sustainable Bio-Based PLA Compounds

Patti

Acierno²,

Latteri

et al. 2020

Polymers

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Cellulose/PLA-based blends (up to 77 vol./vol.% of the added fibers) for applications in extrusion-based technology were realized in an internal mixer by setting different operating conditions. In particular, both the mixing time and temperature were increased in order to simulate a recycling operation (10 or 25 min, 170 or 190 °C) and gain information on the potential reuse of the developed systems. The torque measurements during the compound’s preparation, and the compound’s mechanical tensile features, both in the static and dynamic mode, were evaluated for each investigated composition. The final results confirmed a reduction of the torque trend over time for the PLA matrix, which was attributed to a possible degradation mechanism, and confirmed by infrared spectroscopy. The mechanical behaviour of the pristine polymer changed from elastoplastic to brittle, with a significant loss in ductility going from the lower mixing temperatures up to the higher ones for the longest time. Through the addition of cellulose fibers into the composite systems, a higher stabilization of the torque in the time and an improvement in the mechanical performance were always verified compared to the neat PLA, with a maximum increase in the Young modulus (+100%) and the tensile strength (+57%), and a partial recovery of the ductility.

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“…Nevertheless, the positive benefits coming from the polyurethane treatment on the puncturing strength of the prepared materials were completely lost after the UV aging, probably due to a chemical deterioration of the molecular bonds following UV attack (as attested through ATR analysis). In general, in a composite system, in order to achieve a good migration of stress between the matrix and the fibers, a strong interaction is necessary, such as covalent bonds, and/or secondary forces like van der Waals or hydrogen bonding [23]. Thus, the action of the UV irradiation could also negatively affect the interfacial adhesion between the adopted polymer and the fabric surface, by limiting the adherence and preventing the load transfer.…”

Section: Discussionmentioning

confidence: 99%

The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering

Patti

Acierno²

2019

Polymers

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Polyurethane is a polymer adaptable to different scientific and industrial requirements; nevertheless it is also extremely susceptible to UV radiation, which compromises the physical and mechanical functionality. In this framework, our study investigated the effect of waterborne polyurethane dispersion (WPUD) applied to a polyester (PET)-based fabric, through the impregnation method, on the puncturing and water resistance of the pristine material, before and after UV weathering. Results confirmed an increment of both features in the prepared fabrics, attributed to the PUR textile treatment; but a partially loss of the gained properties in the samples due to the UV weathering. In order to improve the efficiency of the impregnating dispersions, in protecting the durability of the treated materials, the addition of different UV light stabilizers, or/and of crosslinking agent into WPUD was also tested. From the experimental data, it can be concluded that formulations based on WPUD, containing both the crosslinker and UV organic absorber, have displayed an increment of their perforation and water resistance for the treated samples with respect to the starting textile, and contemporary have preserved the features against the UV light. Finally, microscopic and spectroscopic analyses have been performed as further characterization techniques of the samples surface.Polymers 2020, 12, 15 2 of 14 and petroleum depletion concerns, scientific research attention has been paid to study eco-friendly alternatives, i.e., waterborne polyurethane dispersions (WPUDs), with very low VOC emissions and with water as a low-cost, safe for health and the environment, and non-toxic solvent [7]. The aqueous polyurethane characteristics derive essentially from the chemical structure of urethane groups, by which multiple hydrogen bonds between adjacent polymer chains can take place. The chemical arrangement is constituted through hard segments that align in a dry polymer, and self-assemble into strongly hydrogen-bonded areas via flexible soft segments. The multiplicity of strong hydrogen bonds provides the properties commonly associated with a covalently bonded network [8].In the literature, different works have explored the possibility of developing green methods for the synthesis of WPUDs which can be applied as coatings, adhesives and finishing agents, useful for industrial production and application. The results have confirmed that WPUD coatings are endowed with excellent thermal stability, waterproofness and good mechanical properties, in terms of elongation at break and tensile strength [9][10][11][12].In general, the exposure of a polymer to UV radiation causes breakage of the chemical bonds in the material, a subsequent reduction of its molecular weight and a loss in its mechanical features ("photo-oxidative degradation") [13]. Since polyurethane coatings are also utilized for outdoor applications, high durability and weathering resistance may be required for the ambient exposure to ultraviolet (UV) radiation, water/humidity, and tempe...

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Fiber-Matrix Relationship for Composites Preparation

Cited by 38 publications

References 179 publications

Physical and mechanical properties of polyurethane thermoset matrices reinforced with green coconut fibres

Physical and mechanical properties of polyurethane thermoset matrices reinforced with green coconut fibres

Influence of the Processing Conditions on the Mechanical Performance of Sustainable Bio-Based PLA Compounds

The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering

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