Microwave-Cured GFRP Composites Reinforced with Seashell Powder: Mechanical, Thermal, and Micro-CT Characterization

Binder-jet 3D printing responses of sea-shell powder based ceramic composites have been evaluated considering the material consolidation mechanisms and mechanical characterisations. Initial experimental printing trials are done manually, varying the composition of the composite powders from 5% to 50% of the seashell powder and the rest plaster. Overall, the seashell and plaster combinations worked well in terms of achieving the necessary green strengths within the binder-jet process conditions. Scanning electron microscopy and 3-point bending results indicated no significant loss of properties at lower levels of the seashell component, but the strength decreased beyond the 25% mark. The optimum levels of seashell powder are found to be within 15-20% by weight in terms of the best compression strengths. Neat sea-shell powder however goes too sticky immediately after the interaction with the binder liquid and does not show evidence of any binding mechanism that can be accelerated.

In the present work, three natural fibres, namely jute, hemp and bamboo have been hybridized with seashell powder and polypropylene resin as biohybrid composites. Nine samples are considered for this study with various weight propositions of bamboo, hemp, and jute. The mechanical characteristics, such as the flexural, impact, and tensile strength of nine samples, are compared, and the Sample 9 shows very good results; the obtained flexural, tensile strength and impact energy of Sample 9 are 239.36 MPa, 47.84 MPa, and 18.33 J, respectively. The main reason for this is the presence of jute material and layering pattern; Sample 9 contains 60 % Jute, 20 % hemp, and 20 % bamboo; the percentage of jute is high compared to the other eight samples. Furthermore, morphological analysis and thermogravimetric analysis (TGA) have been carried out with Sample 9. While comparing the properties of with the existing dashboard material properties, they show more desirable values and thus, the compositions of Sample 9 material can be used for various vehicle parts. When the experimental results are compared with the finite element analysis (FEA) results, the experimental results match with the FEA results, and few variations are noticed.

Silicon atomic force microscope (AFM) cantilevers having integrated solid-state heaters were originally developed for application to data storage, but have since been applied to metrology, thermophysical property measurements, and nanoscale manufacturing. These applications beyond data storage have strict requirements for mechanical characterization and precise temperature calibration of the cantilever. This paper describes detailed mechanical, electrical, and thermal characterization and calibration of AFM cantilevers having integrated solid-state heaters. Analysis of the cantilever response to electrical excitation in both time and frequency domains aids in resolving heat transfer mechanisms in the cantilever. Raman spectroscopy provides local temperature measurement along the cantilever with resolution near 1 mum and 5degC and also provides local surface stress measurements. Observation of the cantilever mechanical thermal noise spectrum at room temperature and while heated provides insight into cantilever mechanical behavior and compares well with finite-element analysis. The characterization and calibration methodology reported here expands the use of heated AFM cantilevers, particularly the uses for nanomanufacturing and sensing

Use of multi-layered PCM gypsums to improve fire response. Physical, thermal and mechanical characterization

In this present investigation, the influence of reinforcing tungsten (W) particles in High- Density Polyethylene (HDPE) on mechanical and thermal properties, has been studied. W reinforced HDPE composites are processed by melt compounding method, with W varied in proportion of 1%, 3%, 5% and 7% by weight. The test specimens were prepared by injection molding as per ASTM standards and analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Mechanical and Thermal Characterization. XRD results show that, the intensity count at angle 40.3°, 58.7°, 73.6° and 87.1° increases with the increase in wt% of W particles. SEM analysis reveals that, composites containing 1wt% of W has uniform dispersion in the HDPE matrix. In mechanical characterization, tensile strength and flexural strength of the specimen reported a sharp increase with the addition of W at 1wt%, followed by a negative trend for the higher content of W particles. However, the impact strength result shows that specimen with 3wt% of W content has the highest toughness. Further from thermal characterization, Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) results show that degradation temperature and the melting point of composites improve with an increase in W content. Composite with 7wt% W content has the highest degradation temperature and melting point.

Mechanical characterization of kenaf fibre reinforced epoxy composites with pistachio shell and seashell powder as filler materials

Thermal and mechanical behaviour of sisal/phenolic composites

Influence of nanofluid in thermal and mechanical properties of NR alumina polymer nanocomposites

The present study concerns the morphological, mechanical, thermal characterization and activation energy of African teff straw, a natural and almost inexpensive fiber as a potential reinforcement in polymer composites. The fiber is treated with different concentrations of alkali NaOH (5% and 10%) to improve the properties, and the effect has been observed by Fourier transform infrared spectroscopy, scanning electron microscope (SEM) analysis, X-ray diffraction, atomic force microscopy(AFM), mechanical property tester, and thermogravimetric analysis. Flynn–Wall–Ozawa method, Kissinger–Akahira–Sunose method, and Friedman method have been used for calculation of activation energy of untreated and treated teff straw. There is an increase of approximately 31% (280–368 MPa) in tensile strength and 21% (136–164 kJ/mol) in average activation energy in case of 5% alkali-treated fiber compared to untreated one. This treated fiber can be recommended as a reinforcement in polymer composites for light-weight applications.

Mechanical, Thermal and Rheological Characterization of marble waste with Different Coolants

The recycling of polyvinyl chloride (PVC) recovered from the plastic insulations in wires and cables is a rising concern in the current situation due to its hazardous behaviour during recycling. Similarly, high-impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS) used in the structural components of electrical and electronic equipment are also generated in large quantities. In the current work, three agendas were fixed: (a) to determine the effect of recycled polymeric material (HIPS and ABS) recovered from different sources on the mechanical property of the polymeric blends; (b) to formulate a high-impact strength blend; and (c) to deduce a mechanism for improved impact strength. The mechanical characterizations were conducted on the entire blends formulated. Among them, the recycled blend composed of recycled PVC (r-PVC) and recycled ABS (r-ABS) (segregated from uninterrupted power supply housing) and recycled HIPS (r-HIPS; collected from television housing) was confined for further physio-mechanical and thermal analysis. Besides, the r-PVC/r-ABS systems had shown better mechanical properties than r-PVC/r-HIPS systems in similar composition. The impact strength of blend r-PVC/r-ABS (70:30) was found to be 250 J/m, which was 200% more than the blend r-PVC/r-ABS (0:100). The compatibility and non-compatibility in PVC/ABS and PVC/HIPS blends respectively were explained with thermal, mechanical and morphological characterizations. Furthermore, a plausible cross-linking mechanism is developed between ABS and PVC, which controls the release of chlorine atoms into the environment.

A systematic study has been conducted on processing and characterization of epoxy polymer composite to enhance its mechanical, viscoelastic, and thermal properties through optimization of graphene nanoplatelets (GNP). GNP having a two dimensional structure is composed of several layers of graphite nanocrystals stacked together. GNP is expected to provide better reinforcing effect in polymer matrix composites as a nanofiller along with greatly improved mechanical and thermal properties due to its planar structure and ultrahigh aspect ratio. GNP is also considered to be the novel nanofiller due to its exceptional functionalities, high mechanical strength, chemical stability, abundance in nature, and cost effectiveness. Moreover, it possesses an extremely high-specific surface area which carries a high level of transferring stress across the interface and provides higher reinforcement than carbon nanotubes (CNT) in polymer composites. Hence, this research has been focused on the reinforcing effect of the amine-functionalized GNP on mechanical, viscoelastic, and thermal properties of the epoxy resin-EPON 828 composite. Amine functionalized GNP was infused in EPON 828 at different loadings including 0, 0.1, 0.2, 0.3, 0.4, and 0.5 wt% as a reinforcing agent. GNP was infused into epoxy resin Epon 828 Part-A using a high intensity ultrasonic liquid processor followed by a three roll milling processor for better dispersion. The GNP/epoxy mixture was then mixed with the curing agent Epikure 3223 according to the stoichiometric ratio (Part A: Part B = 12:1). The mixture was then placed in a vacuum oven at 40 °C for 10 m to ensure the complete removal of entrapped bubbles and thus reduce the chance of void formation. The as-prepared resin mixture was then poured in rubber molds to prepare samples for mechanical, viscoelastic, and thermal characterization according to ASTM standards. Molds containing liquid epoxy nanocomposites were then kept in the vacuum oven at room temperature for seven days to confirm full curing of the samples according to the manufacturer’s suggestion. Similarly, neat epoxy samples were fabricated to obtain its baseline properties through mechanical, viscoelastic, and thermal characterization and compare these properties with those of nanophased ones. The reinforcing effect of the amine-functionalized GNP on the epoxy was characterized through mechanical, viscoelastic, and thermal analyses. Fracture morphology of mechanically tested samples was evaluated through scanning electronic microscopy (SEM) study. The mechanical properties were determined through flexure test according to the ASTM standard. Dynamic mechanical analysis (DMA) and thermo-mechanical analysis (TMA) were performed to analyze viscoelastic and thermal performances of the composite. In all cases, the 0.4 wt% GNP infused epoxy nanocomposite exhibited the best properties. The 0.4 wt% GNP-loaded epoxy sample showed 20% and 40% improvement in flexure strength and modulus, respectively. Moreover, 16% improvement in the storage modulus and 37% decrease in the coefficient of thermal expansion were observed due to the integration of GNP reinforcement into the epoxy system. Scanning electronic micrographs exhibited smooth fracture surface for the neat sample, whereas the roughness of surface increased due to the GNP incorporation. This is an indication of change in the crack propagation during loading and a higher energy requirement to fracture the GNP-loaded sample.

PZT volume fraction’s impact on electrical and thermal characterization of the piezoelectric composite PU/PZT

The influence of thermal properties on the friction stir welded (FSW) dissimilar aluminium alloys at different tool rotational speeds and tool pin profiles was studied. AA 5083 H111 and AA 6082 T6 of 6 mm aluminium alloy plates are welded by varying the process parameters. The influence of heat generation and heat transfer in the joint efficiency of the weldments are characterised. Heat flow and heat flux for various tool rotation speeds generated between the tool shoulder and workpiece are calculated and analysed. The rate of heat distribution during welding is evaluated by calculating the thermal diffusivity of AA5083 H111 and AA6082 T6. Microhardness test helps to comprehend the influence of the parameters over the mechanical property of the weldments. The results revealed that the thermal characterisation clearly illustrates that an increase in tool rotation speed directly amplifies the heat flow and heat flux in weldments. However, AA 5083 H111 and AA 6082 T6 for varying temperature and reveals that 580°C possessed higher thermal conductivity for AA 6082 T6 (260 W/m°C) and AA 5083 5083 H111 (160 W/m°C), thermal conductivity for AA 6082 T6 (1260 J/Kg°C) and AA 50835083 H111 (1225 J/Kg°C) and thermal Diffusivity was 5.2029 × 10 −5 (m 2 /s) for AA 5083 H111 and 7.61819 × 10 −5 (m 2 /s) for AA 6082 T6.

<abstract> <p>Epoxy resins are formed when epoxy monomers react with crosslinkers that have active hydrogen sites on them such as amine and anhydrides. These cross-linked structures are highly unpredictable and depend on different parameters during curing. Epoxy material when reinforced with nanoparticles has got importance because of its extraordinary enhanced mechanical and thermal properties for structural application. Experimentally it is challenging to tailor these nanostructures and manufacture epoxy-based nanocomposites with desired properties. An experimental approach to preparing these is tedious and costly. The improvement of such materials requires huge experimentation and a better level of control of their properties can't be accomplished up till now. There is a need for numerical experimentation to guide these experimental procedures. With the headway of computational techniques, an alternative for these experiments had given an effective method to characterize these nanocomposites and study their reaction kinetics. Molecular dynamics (MD) simulation is one such technique that works on density function theory and Newton*s second law to characterize these materials with different permutations and combinations during their curing. This review is carried out for MD simulation studies done to date on different epoxies and epoxy-based nanocomposites for their thermal, mechanical, and thermo-mechanical characterization.</p> </abstract>