scholarly journals Flexible Biocomposites with Enhanced Interfacial Compatibility Based on Keratin Fibers and Sulfur-Containing Poly(urea-urethane)s

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1056 ◽  
Author(s):  
Ibon Aranberri ◽  
Sarah Montes ◽  
Itxaso Azcune ◽  
Alaitz Rekondo ◽  
Hans-Jürgen Grande

Feathers are made of keratin, a fibrous protein with high content of disulfide-crosslinks and hydrogen-bonds. Feathers have been mainly used as reinforcing fiber in the preparation of biocomposites with a wide variety of polymers, also poly(urea-urethane)s. Surface compatibility between the keratin fiber and the matrix is crucial for having homogenous, high quality composites with superior mechanical properties. Poly(urea-urethane) type polymers are convenient for this purpose due to the presence of polar functionalities capable of forming hydrogen-bonds with keratin. Here, we demonstrate that the interfacial compatibility can be further enhanced by incorporating sulfur moieties in the polymer backbone that lead to new fiber-matrix interactions. We comparatively studied two analogous thermoplastic poly(urea-urethane) elastomers prepared starting from the same isocyanate-functionalized polyurethane prepolymer and two aromatic diamine chain extenders, bis(4-aminophenyl) disulfide (TPUU-SS) and the sulfur-free counterpart bis(4-aminophenyl) methane (TPUU). Then, biocomposites with high feather loadings (40, 50, 60 and 75 wt %) were prepared in a torque rheometer and hot-compressed into flexible sheets. Mechanical characterization showed that TPUU-SS based materials underwent higher improvement in mechanical properties than biocomposites made of the reference TPUU (up to 7.5-fold higher tensile strength compared to neat polymer versus 2.3-fold). Field Emission Scanning Electron Microscope (FESEM) images also provided evidence that fibers were completely embedded in the TPUU-SS matrix. Additionally, density, thermal stability, and water absorption of the biocomposites were thoroughly characterized.

2017 ◽  
Vol 09 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Xingguo Li ◽  
Bingbing An ◽  
Dongsheng Zhang

Interfacial behavior in the microstructure and the plastic deformation in the protein matrix influence the overall mechanical properties of biological hard tissues. A cohesive finite element model has been developed to investigate the inelastic mechanical properties of bone-like biocomposites consisting of hard mineral crystals embedded in soft biopolymer matrix. In this study, the complex interaction between plastic dissipation in the matrix and bonding properties of the interface between minerals and matrix is revealed, and the effect of such interaction on the toughening of bone-like biocomposites is identified. For the case of strong and intermediate interfaces, the toughness of biocomposites is controlled by the post yield behavior of biopolymer; the matrix with low strain hardening can undergo significant plastic deformation, thereby promoting enhanced fracture toughness of biocomposites. For the case of weak interfaces, the toughness of biocomposites is governed by the bonding property of the interface, and the post-yield behavior of biopolymer shows negligible effect on the toughness. The findings of this study help to direct the path for designing bioinspired materials with superior mechanical properties.


2003 ◽  
Vol 12 (4) ◽  
pp. 096369350301200
Author(s):  
Janakarajan Ramkumar ◽  
Atsushi Kakitsuji ◽  
S.K. Malhotra ◽  
R. Krishnamurthy ◽  
H. Mabuchi ◽  
...  

Ti-50Al alloy and Ti-47Al-3W alloy and its composites have been prepared by reactive arc melting technique using elemental powders. Composites have been reinforced using 3.5, 10 and 18 vol% of Ti2AlC in the matrix of TiAl with and without addition of W and C. By the addition of tungsten and carbon to TiAl alloy, we have produced composites that are reinforced randomly by reacted rod like Ti2AlC particles with fine precipitate of Ti2AlC particles and B2 particles. Compared to Ti-50Al alloys, the Ti-47Al-3W alloy and its composites have superior mechanical properties like bending strength, hardness, fracture toughness and erosion. Ti-47Al-3W/3.5 vol% Ti2AlC has excellent erosion resistance because of the dispersion of fine Ti2AlC and B2 particles in the matrix.


2019 ◽  
Vol 944 ◽  
pp. 509-514 ◽  
Author(s):  
Shan Shan Liu ◽  
He Yi Ge ◽  
Yu Zou ◽  
Juan Chen

Maleic anhydride grafted polypropylene compatibilizer (MAPP) and chitosan (CS) were mixed and used as a compound coupling agent to modify the PP matrix. 5 wt% NaOH and 10 wt% NaOH aqueous solution were used to treat corn stalk fiber (CSF), respectively. The effect of the complex coupling agent and the alkali treatment on the mechanical properties of CSF/PP composite was investigated. Morphological observation of the fracture surfaces was accepted to confirm CSF dispersion and wetting with the help of SEM. The results of the water absorption further demonstrated the binding of the interface between the CSF and the PP matrix. The wetting of the CSF in the PP was improved with the addition of the complex compatibilizer (5% MAPP + 5% CS). The formation of chemical bonding between the fiber and the matrix resulted in enhancing the interfacial compatibility between them. Compared with the pure PP, the flexural strength of 15-UT-5MAPPCS (63.14 MPa) and 15-UT-5MAPPCS (69.35 MPa) increased by 22.5% and 34.5%, respectively. The complex compatibilizer can replace alkaline treatment process to improve the mechanical properties of the composite.


2014 ◽  
Vol 592-594 ◽  
pp. 749-754 ◽  
Author(s):  
R. Senthilkumar ◽  
N. Arunkumar ◽  
M. Manzoor Hussian ◽  
R. Vijayaraj

The expectations over novel composite materials have been increased especially in automotive and aerospace applications due to its superior weight to strength ratio and tailored mechanical properties. In this frame work, aluminum alloy AA5083 alloy matrix reinforced with micron (10% wt – 5% wt) and nanoparticles (1% wt – 5% wt) of Al2O3.The composite samples were fabricated through powder metallurgy route. Optimum amount of reinforcement were determined by evaluating mechanical properties like micro-hardness and compressive strength of composites. The characterizations were probed by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) methods. The results reveal that the composites containing 2% wt of nanoAl2O3and 8 % micro Al2O3reinforcement witnessed superior mechanical properties due to its combined effect of concentration and particulate scale and the great isotropic behavior was achieved by homogenous dispersion of reinforcement in the matrix phase.


2018 ◽  
Vol 31 (3) ◽  
pp. 294-303 ◽  
Author(s):  
Chao Chen ◽  
Jian Wang ◽  
Xinggang Chen ◽  
Xiaoyan Yu ◽  
Qingxin Zhang

In this study, we have prepared a series of composite materials by using a catechol-based phthalonitrile resin as the matrix, and hexagonal boron nitride ( h-BN) nanoparticles as the fillers to improve the toughness and thermal conductivity of the matrix. The surface of nanoparticles was modified with the silane coupling agent (KH550) under mild conditions to enhance the interfacial compatibility, which could be confirmed by Fourier transform infrared spectroscopy and thermogravimetric analysis. The thermal conductivities of composites reached 0.79 W (m·K)−1, which was 3.6 times as much as that of the neat resin, and conformed to the Cheng-Vachon model by fitting the measured values into several heat conduction models. The three-point bending test showed that the toughness and strength were improved at the same time and toughening mechanism was explored by using scanning electron microscope. The h-BN nanoparticles can not only improve the thermal conductivity of the resin but also enhance its mechanical properties.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 709
Author(s):  
Shuaiju Meng ◽  
Lishan Dong ◽  
Hui Yu ◽  
Lixin Huang ◽  
Haisheng Han ◽  
...  

An exceptionally high-strength rare-earth-free Mg–8Al–3Bi (AB83) alloy was successfully fabricated via extrusion and caliber rolling. After three-pass caliber rolling, the homogenous microstructure of the as-extruded AB83 alloy was changed to a necklace-like bimodal structure consisting of ultra-fine dynamic recrystallized (DRXed) grains and microscale deformed grains. Additionally, both Mg17Al12 and Mg3Bi2 nanoprecipitates, undissolved microscale Mg17Al12, and Mg3Bi2 particles were dispersed in the matrix of caliber-rolled (CRed) AB83 alloy. The CRed AB83 sample demonstrated a slightly weakened basal texture, compared with that of the as-extruded sample. Consequently, CRed AB83 showed a tensile yield strength of 398 MPa, an ultimate tensile strength of 429 MPa, and an elongation of 11.8%. The superior mechanical properties of the caliber-rolled alloy were mainly originated from the combined effects of the necklace-like bimodal microstructure containing ultra-fine DRXed grains, the homogeneously distributed nanoprecipitates and microscale particles, as well as the slightly modified basal texture.


2020 ◽  
pp. 089270572093079
Author(s):  
Mehdi Kiani ◽  
Vali Parvaneh ◽  
Mohammad Abbasi ◽  
Ali Dadrasi

This article presents a novel plastic injection molding method for industrial manufacturing of polyvinyl chloride/carbon fiber/graphene (PVC/CF/Gr) nanocomposite pipes. In this method, the reprocessing cycles in the screw cylinder barrel and the fiber (embedded as the material) passes through the extruder lead to enhance Gr dispersion and orientation within the matrix. The mechanical properties of the manufactured nanocomposite pipes are evaluated through three standard tests, namely axial tension, axial compression, and transverse compression. From the experimental results, it is concluded that the second reprocessed PVC/CF/Gr composite demonstrates superior mechanical properties in comparison with the virgin composites. The results indicate an increase of 179% and 154% for Young’s modulus, along with an ultimate tensile strength at 2-wt% Gr with two reprocessing iterations in the cylinder barrel, respectively. Improvement in the mechanical properties of the PVC/CF/Gr composite produced by melt reprocessing could be due to strong interfacial interactions between the polymer matrix and the fibers.


2019 ◽  
Vol 3 (1) ◽  
pp. 30 ◽  
Author(s):  
Jose Vázquez-Moreno ◽  
Ruben Sánchez-Hidalgo ◽  
Estela Sanz-Horcajo ◽  
Jaime Viña ◽  
Raquel Verdejo ◽  
...  

Conventional carbon fiber-reinforced plastics (CFRP) have extensively been used as structural elements in a myriad of sectors due to their superior mechanical properties, low weight and ease of processing. However, the relatively weak compression and interlaminar properties of these composites limit their applications. Interest is, therefore, growing in the development of hierarchical or multiscale composites, in which, a nanoscale filler reinforcement is utilized to alleviate the existing limitations associated with the matrix-dominated properties. In this work, the fabrication and characterization of hierarchical composites are analyzed through the inclusion of graphene to conventional CFRP by vacuum-assisted resin infusion molding.


2010 ◽  
Vol 150-151 ◽  
pp. 1525-1529
Author(s):  
Guang Yi Lin ◽  
Dian Wei Qu ◽  
Yong Xiang Fu

A systematic study has been carried out to investigate matrix properties by introducing nmSiO2 fillers into an epoxy resin matrix. The study has revealed that with shock wave method, nanoparticle infusion brings about superior mechanical properties to the matrix than what is usually given by the other method. The nmSiO2 is dispersed in a high-energy liquid shock wave pressure processing. The resulting structural composites have been tested under tensile loads to evaluate mechanical properties. Shock wave mixing utilized high-energy, high voltage transient shock wave in the water medium to process the material lying in the focal area. Nanoparticles tend to reduce void content of the nanocomposites and thus translate into increased mechanical properties. Focused, the influence of the high-energy shock wave method on the mechanical properties of nanocomposite were systematic studied. Using different processing conditions, the experiments were done to find the best processing. Overall, shock wave method is shown as a promising methode for preparation of aerospace epoxy composites.


Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.


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