scholarly journals Effect of Hygrothermal Aging on the Mechanical Properties of Fluorinated and Nonfluorinated Clay-Epoxy Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Salah U. Hamim ◽  
Raman P. Singh
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Flexural Modulus ◽  
Epoxy Nanocomposites ◽  
Sem Images ◽  
Clay Particles ◽  
Hygrothermal Aging ◽  
Permanent Damage ◽  
Epoxy Polymers ◽  
Hydrophilic Nature

Hydrophilic nature of epoxy polymers can lead to both reversible and irreversible/permanent changes in epoxy upon moisture absorption. The permanent changes leading to the degradation of mechanical properties due to combined effect of moisture and elevated temperature on EPON 862, Nanomer I.28E, and Somasif MAE clay-epoxy nanocomposites are investigated in this study. The extent of permanent degradation on fracture and flexural properties due to the hygrothermal aging is determined by drying the epoxy and their clay-epoxy nanocomposites after moisture absorption. Significant permanent damage is observed for fracture toughness and flexural modulus, while the extent of permanent damage is less significant for flexural strength. It is also observed that permanent degradation in Somasif MAE clay-epoxy nanocomposites is higher compared to Nanomer I.28E clay-epoxy nanocomposites. Fourier transform infrared (FTIR) spectroscopy revealed that both clays retained their original chemical structure after the absorption-desorption cycle without undergoing significant changes. Scanning electron microscopy (SEM) images of the fracture surfaces provide evidence that Somasif MAE clay particles offered very little resistance to crack propagation in case of redried specimens when compared to Nanomer I.28E counterpart. The reason for the observed higher extent of permanent degradation in Somasif MAE clay-epoxy system has been attributed to the weakening of the filler-matrix interface.

Hygrothermal aging effect on the properties of PMMA nanocomposites reinforced by ceramic nanoparticles

2021 ◽  
pp. 002199832110539
Author(s):  
Shervin Jodatnia ◽  
Samrand Rash-Ahmadi
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Mechanical Properties ◽  
Moisture Absorption ◽  
Aging Effect ◽  
Superior Performance ◽  
Multi Criteria Decision Making ◽  
Aging Effects ◽  
Hygrothermal Aging ◽  
Scanning Electron

This paper aimed to evaluate hygrothermal aging effects on polymethyl methacrylate modified with TiO2, SiO2, and Al2O3 nanoparticles in 0.5, 1, and 2% weight fractions. The distribution of nanoparticles was characterized by the scanning electron microscopy (SEM) method. Moisture absorption behavior and mechanical properties of samples in terms of elastic modulus, tensile strength, impact strength, and hardness were investigated. Furthermore, the coefficient of hygrothermal expansion (CHE) for each sample was calculated thanks to experimental data. Finally, by applying the multi-criteria decision making (MCDM) technique, the optimum composition for superior performance was obtained in 0.5 wt% of nanoparticles, more specifically for SiO2.

Moisture Effect on Mechanical Properties of Graphene/Epoxy Nanocomposites

2016 ◽  
Vol 32 (6) ◽  
pp. 673-682 ◽  
Author(s):  
H.-K. Liu ◽  
Y.-C. Wang ◽  
T.-H. Huang
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Moisture Absorption ◽  
Graphene Nanosheets ◽  
Salt Water ◽  
Testing Machine ◽  
Weight Fraction ◽  
Epoxy Nanocomposites ◽  
Moisture Effect ◽  
Superior Mechanical Properties

Abstract2-D graphene nanosheets (GNS) not only have superior mechanical properties, but stacking of GNS in composites is expected to inhibit moisture absorption. In this paper, moisture effect on tensile strength of graphene/epoxy nanocomposites is investigated. Two kinds of graphene reinforcements are used including graphene oxide (GO) and reduced graphene oxide (RGO) with reinforcement weight fraction WGO or WRGO in the range of 0.5 to 3.0wt%. A dispersion agent acetone is added in nanocomposites to enhance graphene dispersion. To evaluate moisture influence, those nanocomposites are soaked in two kinds of liquid including deionized water (DIW) and salt water (saline solution) for seven kinds of soaking periods of time including 24, 48, 72, 100, 400 hours, 30 days, and 60 days. After soaking test, diffusion coefficients of various composites are evaluated; besides tensile strengths of composites are measured by microforce testing machine. In order to correlate the strength with microstructure evolution, several techniques are adopted to analyze morphologies and functionalities of reinforcements and fracture surface of composites. They include Raman spectroscope, X-ray photoelectron spectroscope, and SEM. 2-D GNS are found to effectively enhance nanocomposites by moisture attack, and their corresponding reinforcing mechanisms are proposed.

scholarly journals Influence of Filler Loading on the Mechanical Properties of Flowable Resin Composites

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1477 ◽  
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Bogdan Bâldea ◽  
Ondine Lucaciu ◽  
Aranka Ilea ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Filler Loading ◽  
The Other ◽  
Inorganic Filler ◽  
Resin Composites ◽  
Homogeneous Type ◽  
Sem Images

The aim of this study was to evaluate the correlation between the percent of inorganic filler by weight (wt. %) and by volume (vol. %) of 11 flowable resin composites (FRCs) and their mechanical properties. To establish the correlation, the quantity of inorganic filler was determined by combustion and shape/size analyzed by SEM images. The compressive strength (CS), flexural strength (FS), and flexural modulus (FM) were determined. The CS values were between 182.87-310.38 MPa, the FS values ranged between 59.59 and 96.95 MPa, and the FM values were between 2.34 and 6.23 GPa. The percentage of inorganic filler registered values situated between 52.25 and 69.64 wt. % and 35.35 and 53.50 vol. %. There was a very good correlation between CS, FS, and FM vs. the inorganic filler by wt. % and vol. %. (R2 = 0.8899–0.9483). The highest regression was obtained for the FM values vs. vol. %. SEM images of the tested FRCs showed hybrid inorganic filler for Filtek Supreme XT (A3) and StarFlow (A2) and a homogeneous type of inorganic filler for the other investigated materials. All of the FS values were above 50 MPa, the ISO 4049/2019 limit for FRCs.

Processing of Clay/Epoxy Nanocomposites with A Three-Roll Mill Machine

2002 ◽  
Vol 740 ◽  
Author(s):  
Asma Yasmin ◽  
Jandro L. Abot ◽  
Isaac M. Daniel
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mixing Time ◽  
Clay Content ◽  
Epoxy Nanocomposites ◽  
Clay Particles ◽  
Roll Mill ◽  
Short Period ◽  
Mixing Techniques ◽  
Xrd And Tem

ABSTRACTIn the present study, a three-roll mill machine was used to disperse/exfoliate the nanoclay particles in an epoxy matrix. The compounding process was carried out with varying mixing time and concentrations of clay particles (1 to 10 wt.%). It was found that the longer the mixing time, the higher the degree of intercalation. Mechanical properties, XRD and TEM were used to characterize the nanocomposites. Elastic modulus was found to increase with increasing clay content, however, the tensile strength was not found to vary accordingly. Compared to conventional direct and solution mixing techniques, the compounding of clay/epoxy nanocomposites by a three-roll mill was found to be highly efficient in achieving higher levels of intercalation/exfoliation in a short period of time and also environmentally friendly.

scholarly journals The Degradation of Mechanical Properties in Halloysite Nanoclay-Polyester Nanocomposites Exposed in Seawater Environment

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Mohd Shahneel Saharudin ◽  
Jiacheng Wei ◽  
Islam Shyha ◽  
Fawad Inam
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Flexural Modulus ◽  
Resin Matrix ◽  
Matrix Interface ◽  
Sem Images ◽  
Plasticization Effect ◽  
Polyester Matrix ◽  
Seawater Environment ◽  
The Impact

Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nanocomposites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nanoclay-polyester nanocomposites. Results confirmed that the addition of halloysite nanoclay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nanoclay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease). Young’s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease). The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease). The impact toughness dropped from 0.71 kJ/m2to 0.48 kJ/m2(32% decrease). Interestingly, the fracture toughnessKICincreased with the addition of halloysite nanoclay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nanoclay-matrix interface influenced by seawater absorption and agglomeration of halloysite nanoclay.

scholarly journals Fully Biodegradable Composites: Thermal, Flammability, Moisture Absorption and Mechanical Properties of Natural Fibre-Reinforced Composites with Nano-Hydroxyapatite

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1145 ◽  
Author(s):  
Pooria Khalili ◽  
Xiaoling LIU ◽  
Zirui ZHAO ◽  
Brina Blinzler
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Natural Fibre ◽  
Poly Lactic Acid ◽  
Degradation Temperature ◽  
Conventional Film ◽  
Natural Fabrics ◽  
Burn Rate

Natural fibre-reinforced poly(lactic acid) (PLA) laminates were prepared by a conventional film stacking method from PLA films and natural fabrics with a cross ply layup of [0/90/0/90/0/90], followed by hot compression. Natural fibre (NF) nano-hydroxyapatite (nHA) filled composites were produced by the same manufacturing technique with matrix films that had varying concentrations of nHA in the PLA. Their flammability, thermal, moisture absorption and mechanical properties were analysed in terms of the amount of nHA. The flame behavior of neat PLA and composites evaluated by the UL-94 test demonstrated that only the composite containing the highest quantity of nHA (i.e., 40 wt% nHA in matrix) was found to achieve an FH-1 rating and exhibited no recorded burn rate, whereas other composites obtained only an FH-3. The thermal degradation temperature and mass residue were also observed, via thermogravimetric analysis, to increase when increasing concentrations of nHA were added to the NF composite. The tensile strength, tensile modulus and flexural modulus of the neat resin were found to increase significantly with the introduction of flax fibre. Conversely, moisture absorption was found to increase and mechanical properties to decrease with both the presence of NF and increasing concentrations of nHA, and subsequent mechanical properties experienced an obvious reduction.

scholarly journals Effect of Calcium Carbonate on the Mechanical Properties and Microstructure of Red Clay

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Lijie Chen ◽  
Xuejun Chen ◽  
Xin Yang ◽  
Pengyan Bi ◽  
Xiang Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Carbonate Content ◽  
Shear Tests ◽  
Red Clay ◽  
Precipitated Calcium Carbonate ◽  
Sem Images ◽  
Clay Particles ◽  
Calcium Carbonate Content ◽  
Analysis System

The influence of precipitated calcium carbonate on the strength and microstructure of red clay was studied. Precipitated calcium carbonate was added to red clay at ratios of 0%, 5%, 10%, 15%, and 20%. Shear tests were carried out on the samples to observe the effect of calcium carbonate on the mechanical properties of red clay. The results showed that, with increasing calcium carbonate content, the strength of red clay first decreased and then increased. The maximum strength was obtained for the sample with 20% calcium carbonate. Scanning electron microscopy (SEM) was used to observe the changes in microstructure caused by addition of calcium carbonate. The pores and cracks analysis system (PCAS) was used to quantitatively characterize the microstructure changes detected in SEM images. The addition of calcium carbonate decreased the pore area and increased the total number of pores of red clay. The incorporation of calcium carbonate caused the red clay particles to agglomerate. The higher the calcium carbonate content, the stronger the agglomeration of red clay particles in the soil samples.

scholarly journals MECHANICAL PROPERTIES AND WEAR BEHAVIOUR OF KAOLINITE CLAY PARTICLES REINFORCED EPOXY MATRIX COMPOSITES

2021 ◽  
Vol 15 (2) ◽  
pp. 205-217
Author(s):  
O O. Daramola
Keyword(s):  
Mechanical Properties ◽  
Epoxy Matrix ◽  
Ultrafine Particles ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Sem Images ◽  
Kaolinite Clay ◽  
Clay Particles

Epoxy matrix composites reinforced with clay particles were developed by hand lay-up open mould casting technique. The clay used in this study was pulverized and processed into ultrafine particles through the sedimentation process. The composites were developed by blending the epoxy matrix and hardener with various weight fractions of the ultrafine clay particles (2, 4, 6, 8 and 10 wt%) in open test moulds. In order to accomplish a homogeneous blend of the constituents; manual mixing of the blend was carried out for 3 min. The test specimens were left to cure for 24 hours in the moulds and for additional 27 days at room temperature of 27 ± 2 °C and were thereafter detached from the moulds. The developed composites test specimens were subjected to mechanical tests (flexural, tensile and impact) in accordance with ASTM standards and performed at room temperature. Structural characteristics of the clay particles were determined with the aid of an X-ray diffractometer (XRD). The morphologies of the composites were determined using a scanning electron microscope (SEM). There was a progressive enhancement in the mechanical properties of epoxy composites containing 2-6 wt.% ultrafine clay particles while a drastic decrease in the mechanical properties was noticed in the epoxy/clay composites reinforced with 8-10 wt.% ultrafine clay particles. The SEM images revealed homogeneous particles distributions within the epoxy matrix at lower ultrafine clay particles weight fractions (2 wt. % and 6 wt.%).

Arctic Exposure Studies of Vinyl Foams for Sandwich Composites

2016 ◽  
Author(s):  
Carlos D. Garcia ◽  
Raudel O. Avila ◽  
Pavana Prabhakar
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Sea Water ◽  
Flexural Modulus ◽  
Surface Damage ◽  
Deionized Water ◽  
Compression Tests ◽  
Cold Temperatures ◽  
Water Conditioning ◽  
Experimental Findings

Sea water and cold temperatures appear to have an adverse effect on naval materials resulting in the degradation of their mechanical properties. In this paper, the effects of sea water absorption and arctic conditioning have on the mechanical properties of divinycell foams are discussed. For this study, moisture absorption was periodically measured until weight gain equilibrium or saturation was reached for samples submerged in sea water and deionized water. Diffusivities and saturation values were obtained from moisture uptake curves. It was observed that the moisture content was higher for the vinyl foam samples submerged in deionized water compared to the samples submerged in synthetic sea water. Diffusivities were 9.227E-06 mm2sec and 1.390E-05 mm2sec for deionized water and sea water conditioning, respectively. Flexural and compression tests were then conducted on conditioned samples to compare their response against non-exposed samples. Experimental findings showed degradation in the flexural modulus and the compressive modulus for saturated wet samples and arctic-dry samples. This occurrence can be observed in both tests with more prominent reduction in its flexural modulus for arctic-dry samples and in compression for submerged in deionized water samples. Such a reduction is attributed to the degradation caused by the water, both deionized water and sea water, in the form of surface damage to specimens.

scholarly journals Investigation of Mechanical and Physical Properties of Big Sheep Horn as an Alternative Biomaterial for Structural Applications

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4039
Author(s):  
Tajammul Hussain M. Mysore ◽  
Arun Y. Patil ◽  
G. U. Raju ◽  
N. R. Banapurmath ◽  
Prabhakar M. Bhovi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Yield Strength ◽  
Moisture Absorption ◽  
Failure Strain ◽  
Flexural Modulus ◽  
Physical Property ◽  
Significant Loss ◽  
Two Samples ◽  
Structural Applications

This paper investigates the physical and mechanical properties of bighorns of Deccani breed sheep native from Karnataka, India. The exhaustive work comprises two cases. First, rehydrated (wet) and ambient (dry) conditions, and second, the horn coupons were selected for longitudinal and lateral (transverse) directions. More than seventy-two samples were subjected to a test for physical and mechanical property extraction. Further, twenty-four samples were subjected to physical property testing, which included density and moisture absorption tests. At the same time, mechanical testing included analysis of the stress state dependence with the horn keratin tested under tension, compression, and flexural loading. The mechanical properties include the elastic modulus, yield strength, ultimate strength, failure strain, compressive strength, flexural strength, flexural modulus, and hardness. The results showed anisotropy and depended highly on the presence of water content more than coupon orientation. Wet conditioned specimens had a significant loss in mechanical properties compared with dry specimens. The observed outcomes were shown at par with results for yield strength of 53.5 ± 6.5 MPa (which is better than its peers) and a maximum compressive stress of 557.7 ± 5 MPa (highest among peers). Young’s modulus 6.5 ± 0.5 GPa and a density equivalent to a biopolymer of 1.2 g/cc are expected to be the lightest among its peers; flexural strength 168.75 MPa, with lowest failure strain percentage of 6.5 ± 0.5 and Rockwell hardness value of 60 HRB, seem best in the class of this category. Simulation study identified a suitable application area based on impact and fatigue analysis. Overall, the exhaustive experimental work provided many opportunities to use this new material in various diversified applications in the future.

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