Size Effect of CaCO3 Filler on the Mechanical Properties of SMC Composites

SMC composites consist of chopped glass fiber as a reinforcements, polyester and mineral fillers. Among them, filler is one of the important factors for improving mechanical and thermal properties of composites, but it has not drawn much attention for SMC composites. In this study, the size effect of calcium carbonate as mineral filler on mechanical properties of SMC composites was discussed using five different sizes of commercial calcium carbonates without chopped fiber reinforcement, to focus on the size effect itself. The SMC process was modified to be suitable for a laboratory scale composed of three steps. The mean sizes of the calcium carbonates were 3 – 20 μm, and the specific surface areas were calculated to be 1 – 5 m2/g by BET. Small size of calcium carbonate having high surface area up to 4 m2/g showed high thermal resistance, and showed higher strength comparing to the large fillers because it affected to form a dense packed microstructure.

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EFFECT OF GRADATION AND REPLACEMENT LEVEL ON ALKALI-SILICA REACTIVITY OF MINERAL FILLERS

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2018.21 ◽

2018 ◽

Vol 5 (1) ◽

Author(s):

Noura Sinno ◽

Medhat Shehata

Keyword(s):

Calcium Carbonate ◽

High Surface ◽

High Surface Area ◽

Reactive Aggregate ◽

Silica Filler ◽

Original Rock ◽

Accelerated Mortar Bar Test ◽

Carbonate Filler ◽

Mortar Bar ◽

Mineral Fillers

Mineral fillers are used in concrete for a number of reasons, which include achieving self-consolidation properties. Different fillers are available depending on the type of the original rock. Alkali-silica reaction might occur if the filler is produced from a reactive rock. The present research focuses on evaluating the applicability of the current accelerated mortar bar test, described in ASTM C1260 and CSA A23.2-25A, in evaluating their reactivity. Three different fillers are used: a calcium-carbonate filler, a carbonate silica filler with 27% SiO2, and a siliceous filler produced from reactive aggregate. Two different gradations of the filler obtained from reactive aggregate are tested: 1) Gradation finer than 75 µm; 2) Gradation with 30% passing 150 µm sieve but is retained on 75 µm sieve and remaining 70% passing 75 µm. Results showed that the calcium-carbonate filler and the carbonate silica filler did not show any expansion higher than the non-reactive sand, while the filler obtained from reactive aggregate did not show expansion higher than the control at 14 days for both gradations, with the expansion showing at later age. This might be due to the high surface area of fillers and the reduced permeability affecting the rate of expansion. Hence, the need to extend the testing period beyond the 14-day specified in the standard to be able to see the expansion.

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Preparation and Characterization of Nanocellulose/Chitosan Aerogel Scaffolds Using Chemical-Free Approach

Gels ◽

10.3390/gels7040246 ◽

2021 ◽

Vol 7 (4) ◽

pp. 246

Author(s):

Samsul Rizal ◽

Esam Bashir Yahya ◽

Abdul Khalil H.P.S. ◽

C. K. Abdullah ◽

Marwan Marwan ◽

...

Keyword(s):

Mechanical Properties ◽

Water Uptake ◽

High Surface ◽

Cellulose Nanofibers ◽

High Surface Area ◽

Three Dimensional ◽

High Water ◽

Absorption Capacity ◽

Mechanical And Thermal Properties ◽

High Porosity

Biopolymer-based aerogels are open three-dimensional porous materials that are characterized by outstanding properties, such as a low density, high porosity and high surface area, in addition to their biocompatibility and non-cytotoxicity. Here we fabricated pure and binary blended aerogels from cellulose nanofibers (CNFs) and chitosan (CS), using a chemical-free approach that consists of high-pressure homogenization and freeze-drying. The prepared aerogels showed a different porosity and density, depending on the material and mixing ratio. The porosity and density of the aerogels ranged from 99.1 to 90.8% and from 0.0081 to 0.141 g/cm3, respectively. Pure CNFs aerogel had the highest porosity and lightest density, but it showed poor mechanical properties and a high water absorption capacity. Mixing CS with CNFs significantly enhance the mechanical properties and reduce its water uptake. The two investigated ratios of aerogel blends had superior mechanical and thermal properties over the single-material aerogels, in addition to reduced water uptake and 2-log antibacterial activity. This green fabrication and chemical-free approach could have great potential in the preparation of biopolymeric scaffolds for different biomedical applications, such as tissue-engineering scaffolds.

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Mitigating the Agglomeration of Nanofiller in a Mixed Matrix Membrane by Incorporating an Interface Agent

Membranes ◽

10.3390/membranes11050328 ◽

2021 ◽

Vol 11 (5) ◽

pp. 328

Author(s):

Manh-Tuan Vu ◽

Gloria M. Monsalve-Bravo ◽

Rijia Lin ◽

Mengran Li ◽

Suresh K. Bhatia ◽

...

Keyword(s):

Gas Separation ◽

Polymer Matrix ◽

Ion Beam ◽

High Surface ◽

Mixed Matrix Membrane ◽

Mechanical And Thermal Properties ◽

Separation Membranes ◽

Surface Areas ◽

Separation Membrane ◽

Focus Ion Beam

Nanodiamonds (ND) have recently emerged as excellent candidates for various applications including membrane technology due to their nanoscale size, non-toxic nature, excellent mechanical and thermal properties, high surface areas and tuneable surface structures with functional groups. However, their non-porous structure and strong tendency to aggregate are hindering their potential in gas separation membrane applications. To overcome those issues, this study proposes an efficient approach by decorating the ND surface with polyethyleneimine (PEI) before embedding it into the polymer matrix to fabricate MMMs for CO2/N2 separation. Acting as both interfacial binder and gas carrier agent, the PEI layer enhances the polymer/filler interfacial interaction, minimising the agglomeration of ND in the polymer matrix, which is evidenced by the focus ion beam scanning electron microscopy (FIB-SEM). The incorporation of PEI into the membrane matrix effectively improves the CO2/N2 selectivity compared to the pristine polymer membranes. The improvement in CO2/N2 selectivity is also modelled by calculating the interfacial permeabilities with the Felske model using the gas permeabilities in the MMM. This study proposes a simple and effective modification method to address both the interface and gas selectivity in the application of nanoscale and non-porous fillers in gas separation membranes.

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Mechanical Properties of Hybrid Graphene Nanoplatelet-Nanosilica Filled Unidirectional Basalt Fibre Composites

Nanomaterials ◽

10.3390/nano11061468 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1468

Author(s):

Ummu Raihanah Hashim ◽

Aidah Jumahat ◽

Mohammad Jawaid

Keyword(s):

Mechanical Properties ◽

Polymer Composites ◽

Glass Fibre ◽

Graphene Nanosheets ◽

High Surface ◽

High Surface Area ◽

High Strength ◽

Basalt Fibre ◽

Graphene Nanoplatelet ◽

Dispersion State

Basalt fibre (BF) is one of the most promising reinforcing natural materials for polymer composites that could replace the usage of glass fibre due to its comparable properties. The aim of adding nanofiller in polymer composites is to enhance the mechanical properties of the composites. In theory, the incorporation of high strength and stiffness nanofiller, namely graphene nanoplatelet (GNP), could create superior composite properties. However, the main challenges of incorporating this nanofiller are its poor dispersion state and aggregation in epoxy due to its high surface area and strong Van der Waals forces in between graphene sheets. In this study, we used one of the effective methods of functionalization to improve graphene’s dispersion and also introducing nanosilica filler to enhance platelets shear mechanism. The high dispersive silica nanospheres were introduced in the tactoids morphology of stacked graphene nanosheets in order to produce high shear forces during milling and exfoliate the GNP. The hybrid nanofiller modified epoxy polymers were impregnated into BF to evaluate the mechanical properties of the basalt fibre reinforced polymeric (BFRP) system under tensile, compression, flexural, and drop-weight impact tests. In response to the synergistic effect of zero-dimensional nanosilica and two-dimensional graphene nanoplatelets enhanced the mechanical properties of BFRP, especially in Basalt fibre + 0.2 wt% GNP/15 wt% NS (BF-H0.2) with the highest increment in modulus and strength to compare with unmodified BF. These findings also revealed that the incorporation of hybrid nanofiller contributed to the improvement in the mechanical properties of the composite. BF has huge potential as an alternative to the synthetic glass fibre for the fabrication of mechanical components and structures.

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A facile method to fabricate monolithic alumina–silica aerogels with high surface areas and good mechanical properties

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2020.01.058 ◽

2020 ◽

Vol 40 (6) ◽

pp. 2480-2488 ◽

Cited By ~ 4

Author(s):

Fei Peng ◽

Yonggang Jiang ◽

Junzong Feng ◽

Liangjun Li ◽

Huafei Cai ◽

...

Keyword(s):

Mechanical Properties ◽

High Surface ◽

Silica Aerogels ◽

Surface Areas ◽

Monolithic Alumina

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Recent Advances in Applications of Ceramic Nanofibers

10.5772/intechopen.97118 ◽

2021 ◽

Author(s):

Nuray Kizildag

Keyword(s):

High Surface ◽

Sol Gel ◽

High Surface Area ◽

Ceramic Materials ◽

Water Remediation ◽

Mechanical And Thermal Properties ◽

Chemical Erosion ◽

Recent Advances ◽

Wide Range ◽

Ceramic Nanofibers

Ceramic materials are well known for their hardness, inertness, superior mechanical and thermal properties, resistance against chemical erosion and corrosion. Ceramic nanofibers were first manufactured through a combination of electrospinning with sol–gel method in 2002. The electrospun ceramic nanofibers display unprecedented properties such as high surface area, length, thermo-mechanical properties, and hierarchically porous structure which make them candidates for a wide range of applications such as tissue engineering, sensors, water remediation, energy storage, electromagnetic shielding, thermal insulation materials, etc. This chapter focuses on the most recent advances in the applications of ceramic nanofibers.

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Synthesis and Characterization of Aerogel-derived Cation-substituted Hexaaluminates

MRS Proceedings ◽

10.1557/proc-457-481 ◽

1996 ◽

Vol 457 ◽

Cited By ~ 1

Author(s):

Lin-chiuan Yan ◽

Levi T. Thompson

Keyword(s):

High Temperature ◽

Low Temperature ◽

Catalytic Combustion ◽

High Surface ◽

High Surface Area ◽

Synthesis And Characterization ◽

New Methods ◽

Surface Areas ◽

Different Characteristics

ABSTRACTNew methods have been developed for the synthesis of high surface area cation-substituted hexaaluminates. These materials were prepared by calcining high temperature (ethanol extraction) or low temperature (CO2 extraction) aerogels at temperatures up to 1600°C. Cation-substituted hexaaluminates have emerged as promising catalysts for use in high temperature catalytic combustion. In comparing unsubstituted and cation-substituted hexaaluminates, we found that the phase transformations were much cleaner for the cation-substituted materials. BaCO3 and BaAl2O4 were intermediates during transformation of the unsubstituted materials, while the cation-substituted materials transformed directly from an amorphous phase to crystalline hexaaluminate. Moreover, the presence of substitution cations caused the transformation to occur at lower temperatures. Mn seems to be a better substitution cation than Co since the Mn-substituted materials exhibited higher surface areas and better heat resistances than the Co-substituted materials. The low temperature aerogel-derived materials possessed quite different characteristics from the high temperature aerogel-derived materials. For example, phase transformation pathways were different.

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Modelling and Experimentation on Mechanical Properties of Graphene-Oxide Cement

MATEC Web of Conferences ◽

10.1051/matecconf/201927405004 ◽

2019 ◽

Vol 274 ◽

pp. 05004

Author(s):

Zhiyuan Lin ◽

Ding Fan ◽

Shangtong Yang

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Elastic Properties ◽

High Surface ◽

High Surface Area ◽

Accurate Estimation ◽

Dispersion Property ◽

Length Scales ◽

Analysis And Design ◽

Strength And Durability

Cementitious nano-composites have recently attracted considerable research interest in order to improve their properties such as strength and durability. Graphene oxide (GO) is being considered as an ideal candidate for enhancing the mechanical properties of the cement due to its good dispersion property and high surface area. Much of work has been done on experimentally investigating the mechanical properties of GO-cementitious composites; but there are currently no models for accurate estimation of their mechanical properties, making proper analysis and design of GO-cement based materials a major challenge. This paper attempts to develop a novel multi-scale analytical model for predicting the elastic modulus of GO-cement taking into account the GO/cement ratio, porosity and mechanical properties of different phases. This model employs Eshelby tensor and Mori-Tanaka solution in the process of upscaling the elastic properties of GO-cement through different length scales. In-situ micro bending tests were conducted to elucidate the behavior of the GO-cement composites and verify the proposed model. The obtained results showed that the addition of GO can change the morphology and enhance the mechanical properties of the cement. The developed model can be used as a tool to determine the elastic properties of GO-cement through different length scales.

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