scholarly journals Effect of NaOH Treatment on the Flexural Modulus of Hemp Core Reinforced Composites and on the Intrinsic Flexural Moduli of the Fibers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1428
Author(s):  
Ferran Serra-Parareda ◽  
Francesc Xavier Espinach ◽  
Maria Àngels Pelach ◽  
José Alberto Méndez ◽  
Fabiola Vilaseca ◽  
...  
Keyword(s):  
Value Chain ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Reinforced Composites ◽  
Wood Composites ◽  
Lignocellulosic Residues ◽  
Young’S Moduli ◽  
Reinforcement Content ◽  
Injection Molded ◽  
The Relationship

This paper describes the potential of using hemp core waste in the composite industry. These lignocellulosic residues can be used to produce environmentally friendly and economically viable composites and improve the overall value chain of hemp production. To this purpose, hemp core residues were alkaline treated at different NaOH concentrations and then mechanically defibrated. Hemp core fibers were mixed with polypropylene and injection molded to obtain testing specimens. The effect of sodium hydroxide on the flexural modulus of composites was studied from macro and micro mechanical viewpoints. Results showed remarkable improvements in the flexural modulus due to the presence of hemp core fibers in the composites. At a 50 wt % of reinforcement content, increments around 239%, 250% and 257% were obtained for composites containing fibers treated at a 5, 7.5 and 10 wt % of NaOH, respectively. These results were comparable to those of wood composites, displaying the potential of hemp core residues. The intrinsic flexural modulus of the hemp core fibers was computed by means of micromechanical analysis and was calculated using the ratios between a fiber flexural modulus factor and a fiber tensile modulus factor. The results agreed with those obtained by using models such as Hirsch and Tsai–Pagano. Other micromechanical parameters were studied to fully understand the contribution of the phases. The relationship between the fibers’ intrinsic flexural and Young’s moduli was studied, and the differences between properties were attributed to stress distribution and materials’ anisotropy.

scholarly journals The Effect of Stacking Sequence of Woven Bamboo on Mechanical Behavior of Fiber-Reinforced Composites

2021 ◽  
Vol 56 (2) ◽  
pp. 591-604
Author(s):  
Aidy Ali ◽  
Kannan Rassiah ◽  
M.M.H Megat Ahmad
Keyword(s):  
Mechanical Properties ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Flexural Modulus ◽  
Construction Materials ◽  
Tensile Modulus ◽  
Fiber Reinforced Composites ◽  
Stacking Sequence ◽  
Reinforced Composites ◽  
Fiber Reinforced

Natural fiber-reinforced composites are necessary to increase the use of polymer composite technology. This study investigates a specific type of bamboo species named Gigantochloa Scortechinii (Buluh Semantan), collected from the Bukit Larang Village in Melaka, Malaysia. Bamboo strips with average dimensions of 300 mm x 5 mm x 0.5 mm were weaved in plain-woven bamboo and divided into 2 to 6 laminate layers through 6 layers of E-glass epoxy subjected to the hand lay-up process to produce the hybrid composite. The hybrid composites were prepared in a stacking sequence of plain-woven bamboo and were characterized in their mechanical properties. The behaviors of the tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength improved in the 2-layer laminated hybrid sequences. Still, the opposite trend was observed for the hardness value with the 6-layer laminated mixed sequences. The morphology scanning electron microscopy (SEM) results supported the findings of the mechanical properties, which demonstrated the interaction between the EP and fibers with the selected stacking sequence. The works give sound basis decisions to engineers to apply the Bamboo laminated composites in construction materials and building decoration.

Star-shaped arylacetylene resins derived from silicon

2020 ◽  
Vol 40 (8) ◽  
pp. 676-684
Author(s):  
Niping Dai ◽  
Junkun Tang ◽  
Manping Ma ◽  
Xiaotian Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Mechanical Test ◽  
Flexural Modulus ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Structures And Properties ◽  
High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

scholarly journals Enhanced Impact Properties of Hybrid Composites Reinforced by Carbon Fiber and Polyimide Fiber

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2599
Author(s):  
Boyao Wang ◽  
Bin He ◽  
Zhanwen Wang ◽  
Shengli Qi ◽  
Daijun Zhang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Failure Modes ◽  
Flexural Modulus ◽  
Charpy Impact ◽  
Fiber Reinforced Composites ◽  
Stacking Sequence ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Polyimide Fiber

A series of hybrid fiber-reinforced composites were prepared with polyimide fiber and carbon fiber as the reinforcement and epoxy resin as the matrix. The influence of stacking sequence on the Charpy impact and flexural properties of the composites as well as the failure modes were studied. The results showed that hybrid fiber-reinforced composites yielded nearly 50% increment in Charpy impact strength compared with the ones reinforced by carbon fiber. The flexural performance was significantly improved compared with those reinforced solely by polyimide fibers and was greatly affected by the stacking sequence. The specimens with compressive sides distributed with carbon fiber possessed higher flexural strength, while those holding a sandwich-like structure with carbon fiber filling between the outer layers displayed a higher flexural modulus.

scholarly journals Effects of Rice Straw Powder (RSP) Size and Pretreatment on Properties of FDM 3D-Printed RSP/Poly(Lactic Acid) Biocomposites

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3234
Author(s):  
Wangwang Yu ◽  
Lili Dong ◽  
Wen Lei ◽  
Yuhan Zhou ◽  
Yongzhe Pu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Rice Straw ◽  
Fused Deposition Modeling ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Cost Effective ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Interfacial Compatibility ◽  
3D Printed

To develop a new kind of environment-friendly composite filament for fused deposition modeling (FDM) 3D printing, rice straw powder (RSP)/poly(lactic acid) (PLA) biocomposites were FDM-3D-printed, and the effects of the particle size and pretreatment of RSP on the properties of RSP/PLA biocomposites were investigated. The results indicated that the 120-mesh RSP/PLA biocomposites (named 120#RSP/PLA) showed better performance than RSP/PLA biocomposites prepared with other RSP sizes. Infrared results showed that pretreatment of RSP by different methods was successful, and scanning electron microscopy indicated that composites prepared after pretreatment exhibited good interfacial compatibility due to a preferable binding force between fiber and matrix. When RSP was synergistically pretreated by alkaline and ultrasound, the composite exhibited a high tensile strength, tensile modulus, flexural strength, and flexural modulus of 58.59, 568.68, 90.32, and 3218.12 MPa, respectively, reflecting an increase of 31.19%, 16.48%, 18.75%, and 25.27%, respectively, compared with unmodified 120#RSP/PLA. Pretreatment of RSP also improved the thermal stability and hydrophobic properties, while reducing the water absorption of 120#RSP/PLA. This work is believed to provide highlights of the development of cost-effective biocomposite filaments and improvement of the properties of FDM parts.

scholarly journals Improving the mechanical properties of polypropylene composites with coconut shell particles

2021 ◽  
Vol 30 ◽  
pp. 263498332110074
Author(s):  
Henry C Obasi ◽  
Uchechi C Mark ◽  
Udochukwu Mark
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Flexural Modulus ◽  
Filler Particle ◽  
Tensile Modulus ◽  
Coconut Shell ◽  
Polypropylene Composites ◽  
Increase With Increase ◽  
Pp Composites ◽  
Shell Particles

Conventional inorganic fillers are widely used as fillers for polymer-based composites. Though, their processing difficulties and cost have demanded the quest for credible alternatives of organic origin like coconut shell fillers. Dried shells of coconut were burnt, ground, and sifted to sizes of 63, 150, 300, and 425 µm. The ground coconut shell particles (CSP) were used as a filler to prepare polypropylene (PP) composites at filler contents of 0% to 40% via injection melt blending process to produce PP composite sheets. The effect of the filler particle size on the mechanical properties was investigated. The decrease in the size of filler (CSP) was found to improve the yield strength, tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness of PP by 8.5 MPa, 15.75 MPa, 1.72 GPa, 7.5 MPa, 100 MPa, and 10.5 HR for 63 µm at 40%, respectively. However, the elongation at break and modulus of resilience of the PP composites were seen to increase with increase in the filler size. Scanning electron microscope analysis showed that fillers with 63 µm particle size had the best distribution and interaction with the PP matrix resulting in enhanced properties.

Transverse Young's Moduli and Cell Shapes in Coniferous Early Wood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ugai Watanabe ◽  
Minoru Fujita ◽  
Misato Norimoto
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Bending Moment ◽  
Cell Models ◽  
Young’S Moduli ◽  
Cell Shapes ◽  
The Difference ◽  
Square Cells ◽  
Experimental Values ◽  
The Relationship

Summary The relationship between transverse Young's moduli and cell shapes in coniferous early wood was investigated using cell models constructed by two dimensional power spectrum analysis. The calculated values of tangential Young's modulus qualitatively explained the relationship between experimental values and density as well as the difference in experimental values among species. The calculated values of radial Young's modulus for the species having hexagonal cells agreed well with the experimental values, whereas, for the species having square cells, the calculated values were much larger than the experimental values. This result was ascribed to the fact that the bending moment on the radial cell wall of square cell models was calculated to be small. It is suggested that the asymmetrical shape of real wood cells or the behavior of nodes during ell deformation is an important factor in the mechanism of linear elastic deformation of wood cells.

The Influence of Recycling On Thermotropic Liquid Crystalline Polymer and Glass Fiber Composites

2021 ◽  
Author(s):  
Tianran Chen
Keyword(s):  
High Performance ◽  
Liquid Crystalline ◽  
Tensile Modulus ◽  
Crystalline Polymer ◽  
Fiber Composites ◽  
Reinforced Composites ◽  
Recycling Process ◽  
Mechanical Recycling ◽  
Glass Fiber Composites ◽  
Pp Composites

In this paper, high-performance thermotropic liquidcrystalline polymer (TLCP)/polypropylene (PP) and glassfiber (GF)/PP composites were prepared by the injectionmolding process. Mechanical recycling of TLCP/PP andGF/PP composites consisted of grinding of the injectionmolded specimens and further injection molding of thegranules. The influence of mechanical recycling onmechanical and thermal properties was investigated. In situTLCP/PP maintains tensile modulus and strength duringthe recycling process, indicating the regeneration ofpolymeric fibrils at each reprocessing stage. GF/PPcomposite exhibits deterioration of mechanical propertiesafter recycling because of fiber breakage during processing,which is a very common issue on reusing glass or carbonfiber reinforced composites. The experimental resultsreveal that the TLCP/PP composite has better recyclabilitythan GF/PP.

scholarly journals Connecting Inward and Outward Internationalisation of Malaysian SMEs: A Learning Approach

2018 ◽  
pp. 264-275
Keyword(s):  
Knowledge Sharing ◽  
Value Chain ◽  
Explicit Knowledge ◽  
Small And Medium Enterprises ◽  
Structured Interviews ◽  
Supplier Relationships ◽  
Study Approach ◽  
Medium Enterprises ◽  
The Relationship

When SMEs are part of global value chain, the flows of information in cross-border buyer-supplier relationships which emerge from inward-outward internationalisation connections should be addressed. This study therefore investigates the learning processes of internationalising small and medium enterprises that engage in inward and outward internationalisation. Hence, this study adopts a qualitative case study approach based on ten cases of the internationalising SMEs in Malaysia. Semi-structured interviews with the Managing Directors of the selected SMEs were conducted over a two-year period. Additionally, participant observations were conducted by attending the meetings related to import-export activities and documentations were gathered for data triangulation Findings of this study highlights that the relationship with key foreign suppliers empowered case firms to connect inward to outward internationalisation through collaborative knowledge sharing. The distribution of knowledge through tacit-tacit and tacit-explicit knowledge sharing underpinned by formal planning was a prerequisite for inward-outward internationalisation connections to be established.

scholarly journals German–Russian gas relations in face of the energy transition

2020 ◽  
Vol 6 (4) ◽  
pp. 406-423
Author(s):  
Kirsten Westphal
Keyword(s):  
Climate Change ◽  
Value Chain ◽  
Energy Transition ◽  
Legal Framework ◽  
Paradigm Shifts ◽  
Address Climate Change ◽  
Eu Member States ◽  
Russian Economy ◽  
The Impact ◽  
The Relationship

Russia is the world’s largest gas exporter and Germany is its most important market. Moreover, natural gas is a centerpiece of the Russian economy and the backbone of its energy supply to the Russian population. In terms of its external gas relations, Germany has always kept a special and strategic position, both in terms of volumes, but also in substance. This contribution explores the impact of the energy transition on the bilateral gas relationship. It argues that the bilateral gas relationship has been subjected to various paradigm shifts in the past, but, until recently, the relationship has been seen as in line with the strategic energy triangle of climate change/sustainability, supply security and economic competitiveness. This perception has come into question over two issues: climate change and supply security. Moreover, Germany’s authority over the conduct and the legal framework of bilateral gas relations has been increasingly contested, by Brussels, but also horizontally by other EU member states. At this stage, it is very uncertain whether both sides will manage to maintain and redefine their close energy partnership to address climate change. Decarbonizing the gas value chain would be a centerpiece. This would require a political shift away from securitization to decarbonization, not only in Germany, but even more so in the EU, and in particular, in Russia.

Hybrid effects of carbon fiber and nanoclay as fillers on the performances of recycled wood-plastic composites

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7671-7686
Author(s):  
Young-Rok Seo ◽  
Sang-U Bae ◽  
Birm-June Kim ◽  
Min Lee ◽  
Qinglin Wu
Keyword(s):  
Carbon Fiber ◽  
Impact Strength ◽  
Carbon Fibers ◽  
Synergistic Effects ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Raw Material ◽  
Scanning Electron Micrographs ◽  
Plastic Composite ◽  
The Impact

Waste wood-plastic composite (WPC) was used in this work as a raw material to produce recycled WPCs reinforced with carbon fiber and nanoclay. To evaluate the synergistic effects of carbon fiber and nanoclay, various performances (i.e., microstrucural, mechanical, thermal, water absorption, and electrical properties) were investigated. Scanning electron micrographs and X-ray diffraction analysis of the fillers (carbon fiber and nanoclay) present in the recycled WPCs showed that the nanoclays were properly intercalated when filled with carbon fibers. According to mechanical property analysis, hybrid incorporation of carbon fibers and nanoclays improved impact strength, tensile strength, and flexural strength. However, further incorporation of nanoclays reduced the impact strength and did not improve the tensile modulus or the flexural modulus. The carbon fibers present in the recycled WPCs improved the electrical conductivity of the composites, despite the various fillers that interfered with their electrical conduction. In addition, carbon fibers and nanoclays were mixed into the recycled WPCs to improve the thermal stability of the composites. Finally, the presence of nanoclays in recycled WPCs led to increased water uptake of the composites.

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