scholarly journals Study of Nano-Mechanical Performance of Pretreated Natural Fiber in LDPE Composite for Packaging Applications

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4977
Author(s):  
Muhammad Sulaiman ◽  
Tanveer Iqbal ◽  
Saima Yasin ◽  
Hamayoun Mahmood ◽  
Ahmad Shakeel
Keyword(s):  
Elastic Modulus ◽  
Creep Rate ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Choline Chloride ◽  
Peak Load ◽  
Substantial Effect ◽  
Melt Processing ◽  
Creep Properties ◽  
Composite Samples

In this work, the effects of chemical pretreatment and different fiber loadings on mechanical properties of the composites at the sub-micron scale were studied through nanoindentation. The composites were prepared by incorporating choline chloride (ChCl) pretreated rice husk waste (RHW) in low-density polyethylene (LDPE) using melt processing, followed by a thermal press technique. Nanoindentation experiments with quasi continuous stiffness mode (QCSM) were performed on the surface of produced composites with varying content of pretreated RHW (i.e., 10, 15, and 20 wt.%). Elastic modulus, hardness, and creep properties of fabricated composites were measured as a function of contact depth. The results confirmed the appreciable changes in hardness, elastic modulus, and creep rate of the composites. Compliance curves indicated that the composite having 20 wt.% of pretreated RHW loading was harder compared to that of the pure LDPE and other composite samples. The values of elastic modulus and hardness of the composite containing 20 wt.% pretreated RHW were increased by 4.1% and 24% as compared to that of the pure LDPE, respectively. The creep rate of 42.65 nm/s and change in depth of 650.42 nm were also noted for the composite with RHW loading of 20 wt.%, which showed the substantial effect of holding time at an applied peak load of 100 mN. We believe that the developed composite could be a promising biodegradable packaging material due to its good tribo-mechanical performance.

scholarly journals Substantial Effect of Water on Radical Melt Crosslinking and Rheological Properties of Poly(ε-Caprolactone)

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 491
Author(s):  
Angelica Avella ◽  
Rosica Mincheva ◽  
Jean-Marie Raquez ◽  
Giada Lo Re
Keyword(s):  
Rheological Properties ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Viscous Medium ◽  
Mechanical Analysis ◽  
Substantial Effect ◽  
Melt Processing ◽  
One Step ◽  
Reactive Melt ◽  
Newtonian Behavior

One-step reactive melt processing (REx) via radical reactions was evaluated with the aim of improving the rheological properties of poly(ε-caprolactone) (PCL). In particular, a water-assisted REx was designed under the hypothesis of increasing crosslinking efficiency with water as a low viscous medium in comparison with a slower PCL macroradicals diffusion in the melt state. To assess the effect of dry vs. water-assisted REx on PCL, its structural, thermo-mechanical and rheological properties were investigated. Water-assisted REx resulted in increased PCL gel fraction compared to dry REx (from 1–34%), proving the rationale under the formulated hypothesis. From dynamic mechanical analysis and tensile tests, the crosslink did not significantly affect the PCL mechanical performance. Dynamic rheological measurements showed that higher PCL viscosity was reached with increasing branching/crosslinking and the typical PCL Newtonian behavior was shifting towards a progressively more pronounced shear thinning. A complete transition from viscous- to solid-like PCL melt behavior was recorded, demonstrating that higher melt elasticity can be obtained as a function of gel content by controlled REx. Improvement in rheological properties offers the possibility of broadening PCL melt processability without hindering its recycling by melt processing.

scholarly journals Study of Surface Mechanical Characteristics of ABS/PC Blends Using Nanoindentation

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 637
Author(s):  
Saira Bano ◽  
Tanveer Iqbal ◽  
Naveed Ramzan ◽  
Ujala Farooq
Keyword(s):  
Elastic Modulus ◽  
Polymer Blends ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Maximum Load ◽  
Indentation Load ◽  
Melt Processing ◽  
Indentation Hardness ◽  
Nano Indentation ◽  
Butadiene Styrene

Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) are considered a well-known class of engineering thermoplastics due to their efficient use in automotive, 3D printing, and electronics. However, improvement in toughness, processability, and thermal stability is achieved by mixing together ABS and PC. The present study focuses on the understanding of surface mechanical characterization of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) blends using nano-indentation. Polymer blends sheets with three different proportions of ABS/PC (75:25, 50:50, and 25:75) were fabricated via melt-processing and thermal press. Fourier transform infrared (FTIR) spectroscopy was performed to analyze the intermolecular interactions between the blends’ components. To understand the surface mechanical properties of ABS and PC blends, a sufficient number of nano-indentation tests were performed at a constant loading rate to a maximum load of 100 mN. Creeping effects were observed at the end of loading and start of unloading section. Elastic modulus, indentation hardness, and creep values were measured as a function of penetration displacement in the quasi-continuous stiffness mode (QCSM) indentation. Load-displacement curves indicated an increase in the displacement with the increase in ABS contents while a decreasing trend was observed in the hardness and elastic modulus values as the ABS content was increased. We believe this study would provide an effective pathway for developing new polymer blends with enhanced mechanical performance.

scholarly journals Effect of Loading Rate on Creep Properties of HgCdTe Epitaxial Films

2020 ◽  
Vol 70 (5) ◽  
pp. 493-497
Author(s):  
Hemant Kumar Sharma ◽  
Rajesh Prasad ◽  
Raghvendra Sahai Saxena ◽  
Aditya Gokhale ◽  
Rajesh Kumar Sharma
Keyword(s):  
Elastic Modulus ◽  
Stress Exponent ◽  
Loading Rate ◽  
Creep Behaviour ◽  
Strong Dependence ◽  
Hold Time ◽  
Peak Load ◽  
Epitaxial Films ◽  
Creep Properties ◽  
Loading Rates

Nanoindentation creep studies were performed on Hg1-xCdxTe (x~0.29) epitaxial films using different loading rates of 0.5 mN.s-1, 1 mN.s-1, 2 mN.s-1 and 4 mN.s-1, keeping a constant peak load of 10 mN. A constant hold time of 20 sec at peak load was maintained for all experiments. The effect of loading rate on creep behaviour of material has been investigated. Creep displacement had shown increasing trend with increase of loading rates. Stress exponents were extracted using creep curve fitting with an empirical equation. A strong dependence of loading rate on stress exponent was observed. The value of stress exponent was found varying in the range 0.60-1.76, 0.96-2.23, 0.98-2,87 and 0.90-2.81 for loading rates 0.5 mN.s-1, 1 mN.s-1, 2 mN.s-1 and 4 mN.s-1, respectively. The change of stress exponent was attributed to change of creep mechanism. Hardness and elastic modulus were extracted from load-displacement curves and it was found that with the increase of the loading rate hardness increases, while elastic modulus remains constant. A correlation between variation of hardness and creep displacement has also been presented.

scholarly journals Substantial Effect of Water on Radical Melt Crosslinking and Rheological Properties of Poly(Ε-Caprolactone)

2021 ◽  
Author(s):  
Angelica Avella ◽  
Rosica Mincheva ◽  
Jean-Marie Raquez ◽  
Giada Lo Re
Keyword(s):  
Rheological Properties ◽  
Mechanical Performance ◽  
Radical Reaction ◽  
Tensile Tests ◽  
Viscous Medium ◽  
Mechanical Analysis ◽  
Substantial Effect ◽  
Melt Processing ◽  
One Step ◽  
Reactive Melt

One-step reactive melt processing (REx) via radical reaction was evaluated with the aim of improving the rheological properties of poly(ε-caprolactone) (PCL). In particular, a water-assisted REx was designed under the hypothesis of increasing crosslinking efficiency with water as a low viscous medium in comparison with a slower PCL macroradicals diffusion in the melt state. To assess the effect of dry vs. water-assisted REx on PCL, its structural, thermo-mechanical and rheological properties were investigated. Water-assisted REx resulted in increased PCL gel fraction compared to dry REx (from 1 to 34 %), proving the rationale under the formulated hypothesis. From dynamic mechanical analysis and tensile tests, the crosslink did not significantly affect the PCL mechanical performance. Dynamic rheological measurements showed that higher PCL viscosity was reached with increasing branching/crosslinking and the typical PCL Newtonian behavior was shifting towards a progressively more pronounced shear thinning. A complete transition from viscous- to solid-like PCL melt behavior was recorded, demonstrating that higher melt elasticity can be obtained as a function of gel content by controlled REx. Improvement in rheological properties offers the possibility of broadening PCL melt processability without hindering its recycling by melt processing.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

scholarly journals Effect of Rot-, Fire-, and Water-Retardant Treatments on Jute Fiber and Their Associated Thermoplastic Composites: A Study by FTIR

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2571
Author(s):  
Sweety Shahinur ◽  
Mahbub Hasan ◽  
Qumrul Ahsan ◽  
Nayer Sultana ◽  
Zakaria Ahmed ◽  
...  
Keyword(s):  
Product Development ◽  
Environmental Sustainability ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Jute Fiber ◽  
Thermoplastic Composites ◽  
Ftir Analysis ◽  
Renewable Materials ◽  
Weight Percentage ◽  
Chemical Treatments

Natural renewable materials can play a big role in reducing the consumption of synthetic materials for environmental sustainability. Natural fiber-reinforced composites have attracted significant research and commercial importance due to their versatile characteristics and multi-dimensional applications. As the natural materials are easily rotten, flammable, and moisture absorbent, they require additional chemical modification for use in sustainable product development. In the present research, jute fibers were treated with rot-, fire-, and water-retardant chemicals and their corresponding polymer composites were fabricated using a compression molding technique. To identify the effects of the chemical treatments on the jute fiber and their polymeric composites, a Fourier transformed infrared radiation (FTIR) study was conducted and the results were analyzed. The presence of various chemicals in the post-treated fibers and the associated composites were identified through the FTIR analysis. The varying weight percentage of the chemicals used for treating the fibers affected the physio-mechanical properties of the fiber as well as their composites. From the FTIR analysis, it was concluded that crystallinity increased with the chemical concentration of the treatment which could be contributed to the improvement in their mechanical performance. This study provides valuable information for both academia and industry on the effect of various chemical treatments of the jute fiber for improved product development.

scholarly journals Impact of Prolonged Exposure of Eleven Years to Hot Seawater on the Degradation of a Thermoset Composite

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2154
Author(s):  
Amir Hussain Idrisi ◽  
Abdel-Hamid I. Mourad ◽  
Muhammad M. Sherif
Keyword(s):  
Exposure Time ◽  
Prolonged Exposure ◽  
Mechanical Performance ◽  
Matrix Cracking ◽  
Pull Out ◽  
Strength Based ◽  
Different Temperatures ◽  
River Line ◽  
Composite Samples

This paper presents a long-term experimental investigation of E-glass/epoxy composites’ durability exposed to seawater at different temperatures. The thermoset composite samples were exposed to 23 °C, 45 °C and 65 °C seawater for a prolonged exposure time of 11 years. The mechanical performance as a function of exposure time was evaluated and a strength-based technique was used to assess the durability of the composites. The experimental results revealed that the tensile strength of E-glass/epoxy composite was reduced by 8.2%, 29.7%, and 54.4% after immersion in seawater for 11 years at 23 °C, 45 °C, and 65 °C, respectively. The prolonged immersion in seawater resulted in the plasticization and swelling in the composite. This accelerated the rate of debonding between the fibers and matrix. The failure analysis was conducted to investigate the failure mode of the samples. SEM micrographs illustrated a correlation between the fiber/matrix debonding, potholing, fiber pull-out, river line marks and matrix cracking with deterioration in the tensile characteristics of the thermoset composite.

scholarly journals Effect of Low-Temperature Annealing on Creep Properties of AlSi10Mg Alloy Produced by Additive Manufacturing: Experiments and Modeling

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 179
Author(s):  
Chiara Paoletti ◽  
Emanuela Cerri ◽  
Emanuele Ghio ◽  
Eleonora Santecchia ◽  
Marcello Cabibbo ◽  
...  
Keyword(s):  
Creep Rate ◽  
Applied Stress ◽  
Minimum Creep Rate ◽  
Annealing Treatment ◽  
Constant Load ◽  
Experimental Conditions ◽  
Creep Properties ◽  
Low Temperature Annealing ◽  
Physically Based ◽  
Excellent Description

The effects of postprocessing annealing at 225 °C for 2 h on the creep properties of AlSi10Mg alloy were investigated through constant load experiments carried out at 150 °C, 175 °C and 225 °C. In the range of the experimental conditions here considered, the annealing treatment resulted in an increase in minimum creep rate for a given stress. The reduction in creep strength was higher at the lowest temperature, while the effect progressively vanished as temperature increased and/or applied stress decreased. The minimum creep rate dependence on applied stress was modeled using a physically-based model which took into account the ripening of Si particles at high temperature and which had been previously applied to the as-deposited alloy. The model was successfully validated, since it gave an excellent description of the experimental data.

Mechanical performance and moisture absorption of various natural fiber reinforced thermoplastic composites

2013 ◽  
Vol 130 (2) ◽  
pp. 969-980 ◽  
Author(s):  
Nicole-Lee M. Robertson ◽  
John A. Nychka ◽  
Kirill Alemaskin ◽  
John D. Wolodko
Keyword(s):  
Moisture Absorption ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Thermoplastic Composites ◽  
Fiber Reinforced

Predictions of the Mechanical Performance of Leaf Fiber Thermoplastic Composites by FEA

2021 ◽  
Author(s):  
Faris M. AL-Oqla
Keyword(s):  
Composite Materials ◽  
Cantilever Beam ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Fiber Types ◽  
Natural Fiber Composites ◽  
Pull Out ◽  
Structural Applications

The available potential plant waste could be worthy material to strengthen polymers to make sustainable products and structural components. Therefore, modeling the natural fiber polymeric-based composites is currently required to reveal the mechanical performance of such polymeric green composites for various green products. This work numerically investigates the effect of various fiber types, fiber loading, and reinforcement conditions with different polymer matrices towards predicting the mechanical performance of such natural fiber composites. Cantilever beam and compression schemes were considered as two different mechanical loading conditions for structural applications of such composite materials. Finite element analysis was conducted to modeling the natural fiber composite materials. The interaction between the fibers and the matrices was considered as an interfacial friction force and was determined from experimental work by the pull out technique for each polymer and fiber type. Both polypropylene and polyethylene were considered as composite matrices. Olive and lemon leaf fibers were considered as reinforcements. Results have revealed that the deflection resistance of the natural fiber composites in cantilever beam was enhanced for several reinforcement conditions. The fiber reinforcement was capable of enhancing the mechanical performance of the polymers and was the best in case of 20 wt.% polypropylene/lemon composites due to better stress transfer within the composite. However, the 40 wt.% case was the worst in enhancing the mechanical performance in both cantilever beam and compression cases. The 30 wt.% of polyethylene/olive fiber was the best in reducing the deflection of the cantilever beam case. The prediction of mechanical performance of natural fiber composites via proper numerical analysis would enhance the process of selecting the appropriate polymer and fiber types. It can contribute finding the proper reinforcement conditions to enhance the mechanical performance of the natural fiber composites to expand their reliable implementations in more industrial applications.

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