Single and hybrid organoclay‐filled PLA nanocomposites: Mechanical properties, viscoelastic behavior and fracture toughening mechanism

2021 ◽  
pp. 50784
Author(s):  
Jefferson Lopes Alves ◽  
Paulo Rosa ◽  
Vera C. Realinho ◽  
Marcelo Antunes ◽  
José Velasco ◽  
...  
2015 ◽  
Vol 35 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Rahim Eqra ◽  
Kamal Janghorban ◽  
Habib Daneshmanesh

Abstract Because of extraordinary physical, chemical and mechanical properties, graphene nanosheets (GNS) are suitable fillers for optimizing the properties of different polymers. In this research, the effect of GNS content (up to 1 wt.%) on tensile and flexural properties, morphology of fracture surface, and toughening mechanism of epoxy were investigated. Results of mechanical tests showed a peak for tensile and flexural strength of samples with 0.1 wt.% GNS such that the tensile and flexural strength improved by 13% and 3.3%, respectively. The Young’s modulus and flexural modulus increased linearly with GNS content, although the behavior of the Young’s modulus was more remarkable. Morphological investigations confirmed this behavior because the GNS dispersion in the epoxy matrix was uniform at lower contents and agglomerated at higher contents. Finally, microscopical observation showed that the major toughening mechanism of graphene-epoxy nanocomposites was crack path deflection, which changed the mirror fracture surface of the pure epoxy to rough surface.


2011 ◽  
Vol 335-336 ◽  
pp. 688-694
Author(s):  
Xiao Hui Zhu ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou ◽  
Hong Tao Zhu

Based on the microstructure results of Monte Carlo simulation, a three-dimensional grid model is built up, and imported into the finite element software with C++ language to analyze the mechanical properties of ceramic tool material. The stress field and residual stress of single-phase and multiphase ceramics have been analyzed by the computer simulation technology.


2020 ◽  
Author(s):  
Sahar. Mokhtari ◽  
Anthony.W. Wren

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.


2018 ◽  
Vol 40 (S2) ◽  
pp. E1143-E1150
Author(s):  
Vinay Khandelwal ◽  
Sushanta K. Sahoo ◽  
Gaurav Manik ◽  
Kishor Biswas

Author(s):  
Barbara J. Murienne ◽  
C. Thao D. Nguyen

Changes in sclera mechanical properties have been shown to play an important role in ocular diseases such as glaucoma 1,2,3 and myopia 4,5. In both diseases, those changes in mechanical behavior were observed along with changes in proteoglycan (PG) and associated glycosaminoglycan (GAG) levels, which have been shown to significantly influence the viscoelastic behavior of other tissues 6.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 336 ◽  
Author(s):  
Sylwia Członka ◽  
Anna Strąkowska ◽  
Krzysztof Strzelec ◽  
Agnieszka Adamus-Włodarczyk ◽  
Agnė Kairytė ◽  
...  

Rigid polyurethane foams (RPUFs) were successfully modified with different weight ratios (0.5 wt%, 1.5 wt% and 5 wt%) of APIB-POSS and AEAPIB-POSS. The resulting foams were evaluated by their processing parameters, morphology (Scanning Electron Microscopy analysis, SEM), mechanical properties (compressive test, three-point bending test and impact strength), viscoelastic behavior (Dynamic Mechanical Analysis, DMA), thermal properties (Thermogravimetric Analysis, TGA, and thermal conductivity) and application properties (contact angle, water absorption and dimensional analysis). The results showed that the morphology of modified foams is significantly affected by the type of the filler and filler content, which resulted in inhomogeneous, irregular, large cell shapes and further affected the physical and mechanical properties of resulting materials. RPUFs modified with APIB-POSS represent better mechanical and thermal properties compared to the RPUFs modified with AEAPIB-POSS. The results showed that the best results were obtained for RPUFs modified with 0.5 wt% of APIB-POSS. For example, in comparison with unfilled foam, compositions modified with 0.5 wt% of APIB-POSS provide greater compression strength, better flexural strength and lower water absorption.


2020 ◽  
Vol 978 ◽  
pp. 277-283
Author(s):  
Kishore Kumar Mahato ◽  
Krishna Chaitanya Nuli ◽  
Krishna Dutta ◽  
Rajesh Kumar Prusty ◽  
Bankim Chandra Ray

Fiber reinforced polymeric (FRP) composite materials are currently used in numerous structural and materials related applications. But, during their in-service period these composites were exposed to different changing environmental conditions. Present investigation is planned to explore the effect of thermal shock exposure on the mechanical properties of nanoTiO2 enhanced glass fiber reinforced polymeric (GFRP) composites. The samples were conditioned at +70°C temperature for 36 h followed by further conditioning at – 60°C temperature for the similar interval of time. In order to estimate the thermal shock influence on the mechanical properties, tensile tests of the conditioned samples were carried out at 1 mm/min loading rate. The polymer phase i.e. epoxy was modified with different nanoTiO2 content (i.e. 0.1, 0.3 and 0.5 wt. %). The tensile strength of 0.1 wt.% nanoTiO2 GFRP filled composites exhibited higher ultimate tensile strength (UTS) among all other composites. The possible reason may be attributed to the good dispersion of nanoparticles in polymer matrix corresponds to proper stress transfer during thermal shock conditioning. In order to access the variations in the viscoelastic behavior and glass transition temperature due to the addition of nanoTiO2 in GFRP composite and also due to the thermal shock conditioning, dynamic mechanical thermal analysis (DMTA) measurements were carried out. Different modes of failures and strengthening morphology in the composites were analyzed under scanning electron microscope (SEM).


2016 ◽  
Vol 26 (1) ◽  
pp. 104-118 ◽  
Author(s):  
Robbie Damiani ◽  
LZ Sun

Magnetorheological elastomers (MREs), a class of polymer-based composites with dispersed ferromagnetic micro-particles, fall in the class of smart materials, because their macroscopic or effective rheological properties can be continuously, rapidly, and reversibly changed with the application of a magnetic field. Conventional magnetorheological elastomers exhibit poor mechanical properties and magnetorheological effect as a result of their matrix materials and the particle-matrix interfaces. Here, we investigate the effect of acetone contents on the magnetorheological elastomer microstructure at the interfacial regions using the scanning electron microscope and the three-dimensional nano-CT imaging, as well as determining the overall or effective mechanical properties of magnetorheological elastomers. It is shown that acetone increases both the overall storage modulus and loss factor along with the magnetorheological effect due to acetone’s reaction on the interface as well as its effect on iron particle alignment.


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