The Impact of Matrix Cross-Linking Degree on Chemo-Resistive Properties of Natural Rubber-Carbon Nanostructure Composite

2021 ◽  
Vol 413 ◽  
pp. 146-153
Author(s):  
Santa Stepina ◽  
Igors Klemenoks ◽  
Gita Sakale ◽  
Maris Knite

The aim of this work is to investigate chemo-resistivity properties of natural rubber-carbon nanostructure composite, that’s why a change of diffusion characteristics and reversibility of electro-chemical properties of the composite with different degree values of crosslinks have been analysed. The composites are made from natural rubber (polyisoprene) as matrix material and high structure carbon black as electro-conductive filler. In order to investigate diffusion characteristics of volatile organic compounds (VOC) in relation to chemo-resistive response of composites simultaneous mass, length and electrical resistance change measurements of the samples, when samples are held in VOC and after exposures to VOC were carried out. Electrical resistance increase mechanism in the composite advances with the composite structure development during vulcanization.

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 149
Author(s):  
Karol Leluk ◽  
Stanisław Frąckowiak ◽  
Joanna Ludwiczak ◽  
Tomasz Rydzkowski ◽  
Vijay Kumar Thakur

Recently, biocomposites have emerged as materials of great interest to the scientists and industry around the globe. Among various polymers, polylactic acid (PLA) is a popular matrix material with high potential for advanced applications. Various particulate materials and nanoparticles have been used as the filler in PLA based matrix. One of the extensively studied filler is cellulose. However, cellulose fibres, due to their hydrophilic nature, are difficult to blend with a hydrophobic polymer matrix. This leads to agglomeration and creates voids, reducing the mechanical strength of the resulting composite. Moreover, the role of the various forms of pure cellulose and its particle shape factors has not been analyzed in most of the current literature. Therefore, in this work, materials of various shapes and shape factors were selected as fillers for the production of polymer composites using Polylactic acid as a matrix to fill this knowledge gap. In particular, pure cellulose fibres (three types with different elongation coefficient) and two mineral nanocomponents: precipitated calcium carbonate and montmorillonite were used. The composites were prepared by a melt blending process using two different levels of fillers: 5% and 30%. Then, the analysis of their thermomechanical and physico-chemical properties was carried out. The obtained results were presented graphically and discussed in terms of their shape and degree of filling.


2020 ◽  
Vol 20 (12) ◽  
pp. 7644-7652
Author(s):  
Khalid Marbou ◽  
Waqas Gil ◽  
Amal Al Ghaferi ◽  
Irfan Saadat ◽  
Khalid Alhammadi ◽  
...  

In hostile environments, sensing is critical for many industries such as chemical and oil/gas. Within this industry, the deposition of scales or minerals on various infrastructure components (e.g., pipelines) forms a reliability hazard that needs to be monitored. Therefore, the approach adopted in this study to tackle this issue relies on the use of real-time sensing of specific ions in brine, the natural trigger for ions deposition. In order to do so, electrochemical sensors based on carbon nanotubes (CNTs) are developed, taking advantage of their unique properties facilitated by different synthesis and fabrication methods. One of these promising synthesis methods is inkjet printing of CNT films since in general, it has exceptional benefits over other approaches that are used to print CNTs. Furthermore, it does not need the use templates. In addition, it is a very fast technique with consistent printing results for many applications along with very low cost on various shapes/formfactors. As these sensors are exposed to a hostile environment (chemical, temperature, etc.), the stability of the CNT films is of great importance. In this study, a comprehensive investigation of the stability of CNT surfaces upon exposure to elements is presented. Accordingly, the several impacts of this interaction on physical properties of the surfaces as a function of interaction time and brine chemical composition are assessed. Moreover, the approach used for investigating the impact of this exposure involves the following: surface electrical resistance change using four probe measurements; surface roughness/topography using Atomic Force Microscopy (AFM) along Scanning Electron Microscopy (SEM); quality of CNT through Raman spectroscopy and wettability using the sessile drop method. The sensing capabilities of the devices are investigated by looking at the sensing selectivity of target ions, resetting capabilities, and sensing sensitivity manifested in the electrical resistance change. Consequently, our results indicate that while inkjet films are very promising sensor material, the fabrication and long term stability require further optimization of the films along with the process to make them meet reliability and lifetime requirements in the oil/gas hostile operational environments.


2015 ◽  
Vol 1115 ◽  
pp. 253-257 ◽  
Author(s):  
Yose Fachmi Buys ◽  
Nor Afiza Syafina Lokman

In order to develop environmentally friendly conductive polymer composites, polylactic acid (PLA) was melt blended with natural rubber (NR), with addition of carbon black (CB) as the conductive filler. It was found that the PLA/NR blends were immiscible, and the sea-island and co-continuous morphological structures were observed at PLA/NR with ratio of 80/20 vol% and 60/40 vol% respectively. Addition of CB to 60/40 PLA/NR matrix, brought the composites to become electrically conductive at CB content of 2 phr. It was also found that the impact strength of PLA/NR/CB composite is better than that of the neat PLA.


Author(s):  
Yu Kuronuma ◽  
Tomo Takeda ◽  
Yasuhide Shindo ◽  
Fumio Narita ◽  
Zhijuan Wei

This paper presents a study on the strain sensing behavior of carbon nanotube (CNT)-based polymer composites subjected to tensile loading. Tensile tests were performed on CNT/polycarbonate composites and the responses in strain and electrical resistance were measured during the tests. An analytical model incorporating the electrical tunneling effect due to the matrix material between CNTs was also developed to predict the electrical resistance change resulted from deformation. The analytical predictions were compared with the experimental data.


2012 ◽  
Vol 271-272 ◽  
pp. 297-300
Author(s):  
Xiao Lian Wu ◽  
Jun Lu

Based on the analysis of the conductive mechanism of the conductive rubber used in robot tactile, the paper discussed the influence of the type, particle size and amount of the conductive filler on the dielectric properties of the force-sensitive conductive silicone rubber.Experimental results showed that, for the same mass fraction of the filler material, the particle of bigger size would bring the resistance to decrease more quickly, on the contrary, the smaller one made the the resistance decline.Under the same pressure, with the increase of the amount of graphite filled, the resistivity of the samples would decrease. The resistance of the silicone rubber was changed by the alloy powder added, and the relationship between the tendency of resistance change and the amount of alloy addition was not a single linear, however it significantly increased the range of pressure sensitive of the conductive silicon rubber, and the dielectric properties were improved at the same time.


2020 ◽  
Vol 38 (7A) ◽  
pp. 960-966
Author(s):  
Aseel M. Abdullah ◽  
Hussein Jaber ◽  
Hanaa A. Al-Kaisy

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.


Author(s):  
Byoung-Joon Kim ◽  
Hae-A-Seul Shin ◽  
In-Suk Choi ◽  
Young-Chang Joo

Abstract The electrical resistance Cu film on flexible substrate was investigated in cyclic bending deformation. The electrical resistance of 1 µm thick Cu film on flexible substrate increased up to 120 % after 500,000 cycles in 1.1 % tensile bending strain. Crack and extrusion were observed due to the fatigue damage of metal film. Low bending strain did not cause any damage on metal film but higher bending strain resulted in severe electrical and mechanical damage. Thinner film showed higher fatigue resistance because of the better mechanical property of thin film. Cu film with NiCr under-layer showed poorer fatigue resistance in tensile bending mode. Ni capping layer did not improve the fatigue resistance of Cu film, but Al capping layer suppressed crack formation and lowered electrical resistance change. The NiCr under layer, Ni capping layer, and Al capping layer effect on electrical resistance change of Cu film was compared with Cu only sample.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 799
Author(s):  
Justyna Miedzianowska ◽  
Marcin Masłowski ◽  
Przemysław Rybiński ◽  
Krzysztof Strzelec

Increasingly, raw materials of natural origin are used as fillers in polymer composites. Such biocomposites have satisfactory properties. To ensure above-average functional properties, modifications of biofillers with other materials are also used. The presented research work aimed to produce and characterize elastomeric materials with a straw-based filler and four different types of montmorillonite. The main research goal was to obtain improved functional parameters of vulcanizates based on natural rubber. A series of composites filled with straw and certain types of modified and unmodified nano-clays in various ratios and amounts were prepared. Then, they were subjected to a series of tests to assess the impact of the hybrids used on the final product. It has been shown that the addition of optimal amounts of biofillers can, inter alia, increase the tensile strength of the composite, improve damping properties, extend the burning time of the material and affect the course of vulcanization or cross-linking density.


Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 447
Author(s):  
Miguel Alfonso Quiñones-Reveles ◽  
Víctor Manuel Ruiz-García ◽  
Sarai Ramos-Vargas ◽  
Benedicto Vargas-Larreta ◽  
Omar Masera-Cerutti ◽  
...  

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. & Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p < 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.


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