scholarly journals Nanocellulose Bulk Material Prepared by Steam Treatment and Hot Press Molding: Material Processing and Machining Test

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 853
Author(s):  
Jung-Woong Kim ◽  
Hyun-Chan Kim ◽  
Lindong Zhai ◽  
Dickens Owino Agumba ◽  
Jaehwan Kim
Keyword(s):  
Mechanical Properties ◽  
Bulk Material ◽  
Circular Disk ◽  
Steam Treatment ◽  
Hydroxyl Groups ◽  
Hot Press ◽  
Macro Scale ◽  
Machining Test ◽  
Mill Machining ◽  
Press Molding

Nanocellulose (NC) has been spotlighted as a new building block of future materials since it has many advantages, such as being lightweight and environment-friendly and having high mechanical properties and heat resistance. However, the use of NC requires an upscale manufacturing process to maintain its advantageous properties. Herein, the process of assembling NC into a macro-scale bulk material was developed through a combination of steam treatment and hot press molding. The steam treatment was applied to an NC paste to energize the hydroxyl groups in the cellulose, followed by two stages of hot press molding, which helped in the self-assembly of NC without adhesives. Cellulose nanocrystals were used as the NC, and circular disk shape specimens were prepared. The mechanical properties of the prepared bulk material were higher than typical engineering plastics. In addition, an end mill machining test of the NC bulk material showed its machinability. This paper showed the processing feasibility of NC bulk material, which can substitute plastics.

scholarly journals Transcrystallization of Isotactic Polypropylene/Bacterial Cellulose Hamburger Composite

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 508 ◽  
Author(s):  
Bo Wang ◽  
Fu-hua Lin ◽  
Xiang-yang Li ◽  
Xu-ran Ji ◽  
Si-xiao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bacterial Cellulose ◽  
Isotactic Polypropylene ◽  
Crystallization Rate ◽  
Sem Analysis ◽  
Hydroxyl Groups ◽  
Hot Press ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Fourier Transform

Isotactic polypropylene (iPP) is a commonly used thermoplastic polymer with many excellent properties. But high brittleness, especially at low temperatures, limits the use of iPP. The presence of transcrystallization of iPP makes it possible for fiber-reinforced iPP composites with higher strength. Bacterial cellulose (BC) is a kind of cellulose with great potential to be used as a new filler to reinforce iPP due to its high crystallinity, biodegradability and efficient mechanical properties. In this study, the iPP/BC hamburger composite was prepared by a simple hot press and maleic anhydride grafted polypropylene (MAPP) was used to improve the interface compatibility of iPP and BC. The polarizing microscope (POM) photograph shows that BC successfully induces the transcrystallization of iPP. The differential Scanning Calorimeter (DSC) date proves that the addition of BC could improve the thermal properties and crystallization rate of the composite. Especially, this change is more obvious of the iPP/MAPP/BC. The mechanical properties of the iPP/BC composites were greatly increased. This DSC date is higher than BC; we used BC particles to enhance the iPP in our previous research. The scanning Electron Microscope (SEM) analysis intuitively shows that the interface of the iPP/MAPP/BC is more smooth and flat than the iPP/BC. The fourier Transform infrared spectroscopy (FT-IR) analysis of the iPP/BC hamburger composites was shown that a new C=O group vibration appeared at 1743 cm−1, which indicated that the hydrogen bond structure of BC molecules was weakened and some hydroxyl groups were substituted after modification which can increase the lipophilicity of BC. These results indicated that the BC fiber can easily induce the transcrystallization of iPP, which has excellent mechanical properties. Moreover, the addition of MAPP contributes greatly to the interface compatibility of iPP and BC.

Influence of Hot Pressing Parameters on Mechanical Properties of PP-HA Bio-Composites

2009 ◽  
Author(s):  
Mousa Younesi ◽  
Mohammad Ebrahim Bahrololoom ◽  
Hamidreza Fooladfar
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Young’S Modulus ◽  
Hot Pressing ◽  
Young's Modulus ◽  
Impact Resistance ◽  
Hot Press ◽  
Different Types ◽  
Press Molding

This paper focuses on the effects of pressure and temperature in hot press molding on the mechanical properties of polypropylene-hydroxyapatite composites with two different types of silanated and unsilanated hydroxyapatite. Density, crystallinity, ultimate tensile strength, Young’s modulus and impact resistance were evaluated for the two types of composites. Increasing pressure caused enhancement of density, crystallinity, MFI, ultimate tensile strength and Young’s modulus. Increases in temperature increased MFI, ultimate tensile strength and Young’s modulus whilst decreased impact resistance of composites. Effects of increasing pressure and temperature on the mechanical properties of polypropylene-silanated hydroxyapatite were less than their effects on the mechanical properties of polypropylene-unsilanated hydroxyapatite. Micrographs showed changes in fracture mode from ductile to brittle with increasing pressure and temperature during hot press molding.

scholarly journals Preparation of Solution Impregnated Continuous Carbon Fibre Reinforced Poly (Phthalazinone Ether Sulfone Ketone) Composites

2009 ◽  
Vol 18 (1) ◽  
pp. 096369350901800 ◽  
Author(s):  
Liang Zheng ◽  
Gong Xiong Liao ◽  
Xi Gao Jian
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibre ◽  
Polymer Solution ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Hot Press ◽  
Molding Method ◽  
Press Molding ◽  
Properties Of Composites

Continuous carbon fibre reinforced Poly (phthalazinone ether sulfone ketone) (PPESK) composites were prepared using a solution impregnation process and hot-press molding method. The effects of polymer solution viscosities on fibre impregnation, fibre volume fraction and thereby on mechanical properties of composites were studied. The results show that the fibre impregnation and fibre volume fraction decreased with increasing polymer solution viscosities, and the mechanical properties of composites mainly depended on the fibre volume content.

Fabrication and Properties of Ti3AlC2-Based Ceramics by Two-Step Method

2007 ◽  
Vol 280-283 ◽  
pp. 1365-1368 ◽  
Author(s):  
Chang An Wang ◽  
Ai Guo Zhou ◽  
Chun Qing Peng ◽  
Yong Huang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Flexural Strength ◽  
Bulk Material ◽  
Second Step ◽  
Pressureless Sintering ◽  
Hot Press ◽  
Step Method ◽  
Reactive Powder

A two-step method was presented to fabricate Ti3AlC2-based ceramics. The first step was to synthesize a reactive powder, which mainly contains Ti2AlC, by pressureless sintering (PLS) in argon at 1500°C for 10 mins with a heating rate of 20°C×min-1. The second step was to hot press the powder to a bulk material at 1300°C for 60 mins. The second step not only densified the powder, but also promoted the phase transformation from Ti2AlC to Ti3AlC2. The ceramic sample prepared by this method consists of Ti3AlC2, Ti2AlC and a little amount of TiC. It has excellent mechanical properties: density is 4.26 ± 0.02 g×cm-3, flexural strength is 664.4 ± 90 MPa, Vickers hardness is 6.4 ± 0.5 GPa, and fracture toughness (KIC) is 9.9 ± 0.5 MPa m1/2. The so high values of strength and fracture toughness are never reported in any literature about this material, as far as we aware.

The Future of Plasma-Based Surface Engineering Techniques in Tribology (Keynote)

2005 ◽  
Author(s):  
Allan Matthews ◽  
Adrian Leyland
Keyword(s):  
Surface Engineering ◽  
Performance Enhancement ◽  
Bulk Material ◽  
Cost Savings ◽  
Cost Effective ◽  
Ceramic Coatings ◽  
Performance Improvements ◽  
Treatment Techniques ◽  
Wide Range ◽  
Macro Scale

Over the past twenty years or so, there have been major steps forward both in the understanding of tribological mechanisms and in the development of new coating and treatment techniques to better “engineer” surfaces to achieve reductions in wear and friction. Particularly in the coatings tribology field, improved techniques and theories which enable us to study and understand the mechanisms occurring at the “nano”, “micro” and “macro” scale have allowed considerable progress to be made in (for example) understanding contact mechanisms and the influence of “third bodies” [1–5]. Over the same period, we have seen the emergence of the discipline which we now call “Surface Engineering”, by which, ideally, a bulk material (the ‘substrate’) and a coating are combined in a way that provides a cost-effective performance enhancement of which neither would be capable without the presence of the other. It is probably fair to say that the emergence and recognition of Surface Engineering as a field in its own right has been driven largely by the availability of “plasma”-based coating and treatment processes, which can provide surface properties which were previously unachievable. In particular, plasma-assisted (PA) physical vapour deposition (PVD) techniques, allowing wear-resistant ceramic thin films such as titanium nitride (TiN) to be deposited on a wide range of industrial tooling, gave a step-change in industrial productivity and manufactured product quality, and caught the attention of engineers due to the remarkable cost savings and performance improvements obtained. Subsequently, so-called 2nd- and 3rd-generation ceramic coatings (with multilayered or nanocomposite structures) have recently been developed [6–9], to further extend tool performance — the objective typically being to increase coating hardness further, or extend hardness capabilities to higher temperatures.

In situ TEM observation of the microstructural characteristics and mechanical properties of vacuum hot-press sintered Co–30Cr–6Mo alloys

Vacuum ◽  
2020 ◽  
Vol 176 ◽  
pp. 109333
Author(s):  
Shih-Hsien Chang ◽  
Lung-Yi Lin ◽  
Kuo-Tsung Huang
Keyword(s):  
Mechanical Properties ◽  
In Situ Tem ◽  
Hot Press ◽  
Microstructural Characteristics

Friction and Wear of Potassium Titanate Whisker Filled Carbon Fabric/Phenolic Polymer Composites

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Xinrui Zhang ◽  
Xianqiang Pei ◽  
Qihua Wang ◽  
Tingmei Wang
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Dip Coating ◽  
Hot Press ◽  
Carbon Fabric ◽  
Potassium Titanate ◽  
Transfer Films ◽  
Fabric Composites ◽  
Phenolic Polymer ◽  
Press Molding

Carbon fabric/phenolic composites modified with potassium titanate whisker (PTW) were prepared by a dip-coating and hot-press molding technique, and the tribological properties of the resulting composites were investigated systematically using a ring-on-block arrangement under different sliding conditions. Experimental results showed that the optimal PTW significantly decreased the wear-rate. The worn surfaces of the composites and the transfer film formed on the counterpart steel ring were examined by scanning electron microscopy (SEM) to reveal the wear mechanisms. The transfer films formed on the counterpart surfaces made contributions to the improvement of the tribological behavior of the carbon fabric composites. The friction and wear of the filled carbon fabric composites was significantly dependent on the sliding conditions. It is observed that the wear-rate increased with increasing applied load and sliding speeds.

scholarly journals Tribological and Mechanical Properties of Multicomponent CrVTiNbZr(N) Coatings

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Yin-Yu Chang ◽  
Cheng-Hsi Chung
Keyword(s):  
Mechanical Properties ◽  
Nitrogen Content ◽  
Adhesion Strength ◽  
Mechanical Performance ◽  
Bulk Material ◽  
High Entropy Alloy ◽  
Composition Gradient ◽  
Multilayered Structures ◽  
High Entropy ◽  
Alloy Target

Multi-element material coating systems have received much attention for improving the mechanical performance in industry. However, they are still focused on ternary systems and seldom beyond quaternary ones. High entropy alloy (HEA) bulk material and thin films are systems that are each comprised of at least five principal metal elements in equally matched proportions, and some of them are found possessing much higher strength than traditional alloys. In this study, CrVTiNbZr high entropy alloy and nitrogen contained CrVTiNbZr(N) nitride coatings were synthesized using high ionization cathodic-arc deposition. A chromium-vanadium alloy target, a titanium-niobium alloy target and a pure zirconium target were used for the deposition. By controlling the nitrogen content and cathode current, the CrNbTiVZr(N) coating with gradient or multilayered composition control possessed different microstructures and mechanical properties. The effect of the nitrogen content on the chemical composition, microstructure and mechanical properties of the CrVTiNbZr(N) coatings was investigated. Compact columnar microstructure was obtained for the synthesized CrVTiNbZr(N) coatings. The CrVTiNbZrN coating (HEAN-N165), which was deposited with nitrogen flow rate of 165 standard cubic centimeters per minute (sccm), exhibited slightly blurred columnar and multilayered structures containing CrVN, TiNbN and ZrN. The design of multilayered CrVTiNbZrN coatings showed good adhesion strength. Improvement of adhesion strength was obtained with composition-gradient interlayers. The CrVTiNbZrN coating with nitrogen content higher than 50 at.% possessed the highest hardness (25.2 GPa) and the resistance to plastic deformation H3/E*2 (0.2 GPa) value, and therefore the lowest wear rate was obtained because of high abrasion wear resistance.

scholarly journals Mechanical Properties of Graphene Oxide Coupled by Multi-Physical Field: Grain Boundaries and Functional Groups

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Grain Boundaries ◽  
Functional Groups ◽  
Oxygen Content ◽  
Tensile Fracture ◽  
Hydroxyl Groups ◽  
Molecular Configuration ◽  
Spatial Design ◽  
Out Of Plane

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.

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