ENHANCEMENT OF ELECTRICAL CONDUCTIVITY AND FILLER DISPERSION OF CARBON NANOTUBE FILLED NATURAL RUBBER COMPOSITES BY LATEX MIXING AND IN SITU SILANIZATION

2016 ◽  
Vol 89 (2) ◽  
pp. 272-291 ◽  
Author(s):  
Yeampon Nakaramontri ◽  
Charoen Nakason ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Threshold Concentration ◽  
Attenuated Total Reflection ◽  
Rubber Matrix ◽  
Melt Mixing ◽  
In Situ Functionalization

ABSTRACT Carbon nanotube (CNT)-filled natural rubber (NR) composites were prepared by melt and by latex mixing methods. Also in situ functionalization of CNTs with a silane coupling agent, namely bis(triethoxysilylpropyl)tetrasulfide (TESPT), was done to improve the filler–rubber interactions between CNT surfaces and rubber molecules. The grafting of TESPT molecules on CNT surfaces was confirmed by attenuated total reflection (ATR)–Fourier transform infrared (FTIR) spectroscopy and by the improvement of composite properties. Tensile properties were determined to assess the reinforcement efficiency of the CNTs in the composites. Also, electrical conductivity of the composites was measured to assess the formation of CNT networks (or connected conductive CNT pathways) in the rubber matrix. The results indicate that the composites prepared by latex mixing, in particular with the TESPT, had better tensile properties and electrical conductivities than the composites made by melt mixing. The lowest percolation threshold concentration, about 0.55 phr of CNTs, was observed in the latex–CNT composites, and three-dimensional network formations of CNTs in the rubber matrix were found with added TESPT, used by in situ functionalization. The improvement of filler–rubber interactions with the addition of TESPT was also examined by temperature scanning stress relaxation measurements, revealing the relaxation modulus, the relaxation spectrum, and an estimate of the cross-link density.

INFLUENCE OF MODIFIED NATURAL RUBBER ON PROPERTIES OF NATURAL RUBBER–CARBON NANOTUBE COMPOSITES

2015 ◽  
Vol 88 (2) ◽  
pp. 199-218 ◽  
Author(s):  
Yeampon Nakaramontri ◽  
Charoen Nakason ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Natural Rubber ◽  
Functional Groups ◽  
Relaxation Modulus ◽  
Threshold Value ◽  
Attenuated Total Reflection ◽  
Homogeneous Distribution ◽  
Roll Mill ◽  
Nanotube Composites

ABSTRACT Carbon nanotube (CNT)–filled natural rubber (NR) composites were prepared by using an internal mixer and a two-roll mill. Various types of NR, including unmodified NR, epoxidized NR (ENR), and maleated NR (MNR), were used. The chemical reactions between rubber molecules and functional groups on the CNT surface were characterized by attenuated total reflection Fourier transform infrared spectroscopy. Cure characteristics, tensile properties, relaxation behavior, and electrical conductivity of the various gum rubbers and the CNT-filled rubber composites were investigated. It was found that the addition of CNTs significantly affected the composite properties. This is due not only to the excellent properties of the CNT itself but also to the physical and chemical interactions between modified rubber molecules and CNT surfaces. On comparison between the three types of NR, it was observed that the ENR-CNT composite showed the highest values of delta torque, tensile strength, and initial relaxation modulus. This confirms the homogeneous distribution of CNT particles in the ENR matrix, which in turn resulted from enhanced interactions of functional groups on CNT surfaces and epoxide groups in ENR molecules. Furthermore, electrical conductivity as a function of CNT content was examined to estimate the electrical percolation threshold value and to determine the state of dispersion of CNTs.

scholarly journals Combination of Self-Healing Butyl Rubber and Natural Rubber Composites for Improving the Stability

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 443
Author(s):  
Kunakorn Chumnum ◽  
Ekwipoo Kalkornsurapranee ◽  
Jobish Johns ◽  
Karnda Sengloyluan ◽  
Yeampon Nakaramontri
Keyword(s):  
Natural Rubber ◽  
Dynamic Mechanical Properties ◽  
Attenuated Total Reflection ◽  
Rubber Matrix ◽  
Self Healing ◽  
Mechanical And Electrical Properties ◽  
Natural Rubber Composites ◽  
Tan Δ ◽  
The Stability ◽  
Physical And Chemical

The self-healing composites were prepared from the combination of bromobutyl rubber (BIIR) and natural rubber (NR) blends filled with carbon nanotubes (CNT) and carbon black (CB). To reach the optimized self-healing propagation, the BIIR was modified with ionic liquid (IL) and butylimidazole (IM), and blended with NR using the ratios of 70:30 and 80:20 BIIR:NR. Physical and chemical modifications were confirmed from the mixing torque and attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR). It was found that the BIIR/NR-CNTCB with IL and IM effectively improved the cure properties with enhanced tensile properties relative to pure BIIR/NR blends. For the healed composites, BIIR/NR-CNTCB-IM exhibited superior mechanical and electrical properties due to the existing ionic linkages in rubber matrix. For the abrasion resistances, puncture stress and electrical recyclability were examined to know the possibility of inner liner applications and Taber abrasion with dynamic mechanical properties were elucidated for tire tread applications. Based on the obtained Tg and Tan δ values, the composites are proposed for tire applications in the future with a simplified preparation procedure.

scholarly journals A Green Approach for Preparing High-Loaded Sepiolite/Polymer Biocomposites

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 46 ◽  
Author(s):  
Barbara Di Credico ◽  
Irene Tagliaro ◽  
Elkid Cobani ◽  
Lucia Conzatti ◽  
Massimiliano D’Arienzo ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Rubber Matrix ◽  
Renewable Materials ◽  
Melt Mixing ◽  
Global Industry ◽  
Green Approach ◽  
Filler Network ◽  
Mechanical Performances ◽  
Synthetic Approaches

Global industry is showing a great interest in the field of sustainability owing to the increased attention for ecological safety and utilization of renewable materials. For the scientific community, the challenge lies in the identification of greener synthetic approaches for reducing the environmental impact. In this context, we propose the preparation of novel biocomposites consisting of natural rubber latex (NRL) and sepiolite (Sep) fibers through the latex compounding technique (LCT), an ecofriendly approach where the filler is directly mixed with a stable elastomer colloid. This strategy favors a homogeneous dispersion of hydrophilic Sep fibers in the rubber matrix, allowing the production of high-loaded sepiolite/natural rubber (Sep/NR) without the use of surfactants. The main physicochemical parameters which control Sep aggregation processes in the aqueous medium were comprehensively investigated and a flocculation mechanism was proposed. The uniform Sep distribution in the rubber matrix, characteristic of the proposed LCT, and the percolative filler network improved the mechanical performances of Sep/NR biocomposites in comparison to those of analogous materials prepared by conventional melt-mixing. These outcomes indicate the suitability of the adopted sustainable procedure for the production of high-loaded clay–rubber nanocomposites with remarkable mechanical features.

Investigation of the Crack Propagation Behavior of the Multiwalled Carbon Nanotube/Graphite/Natural Rubber Hybrid Nanocomposites Using Digital Image Correlation Technique

2019 ◽  
Vol 14 (12) ◽  
pp. 1766-1770
Author(s):  
Hasan Kasim ◽  
Ahmad Naser Aldeen ◽  
Yücel Can ◽  
Murat Yazici
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Digital Image Correlation ◽  
Crack Propagation ◽  
Natural Rubber ◽  
Digital Image ◽  
Multiwalled Carbon Nanotube ◽  
Hybrid Nanocomposites ◽  
Image Correlation ◽  
Multiwalled Carbon

In the presented study, a hybrid Natural Rubber (NR) based semiconductive nanocomposites was examined to obtain better electrical and mechanical properties. The hybrid nanocomposite produced by incorporation of the Multiwalled Carbon Nanotube (MWCNT) and graphite nanoparticles into the NR. The conventional curing additives also included in the compound. A functionalized MWCNT (1, 2 and 3 phr's) with 3 phr graphite quotas were studied to produce the NR nanocomposites. The MWCNT/Graphite and NR mixed homogeneously to advance the interfacial interaction with the matrix. The graphite nano-particulates added to obtain 3D electrical connectivity network in the hybrid nanocomposites by becoming bridging points between multiwalled carbon nanotubes. Nanocomposites were produced as 3 mm sheets in a steel mold by vulcanizing at 165 °C for 10 min under pressure. The single-edge notched tension specimens were subjected to estimate crack propagation and electrical resistance relation. Digital Image Correlation (DIC) technique was used to observe the crack resistivity function. The results evaluated to clarify the relationship between crack length, MWCNT filler ratio, and electrical conductivity properties. MWCNTs are generally preferred as the reinforcements for their very high aspect ratio and excellent specific surface area properties. However, the electrical conductivity of the nanocomposites is owing to the constitution of a continuous conductive 3D network of MWCNT and Graphite in the NR matrix.

scholarly journals 3D Printed Thermoelectric Polyurethane/Multiwalled Carbon Nanotube Nanocomposites: A Novel Approach towards the Fabrication of Flexible and Stretchable Organic Thermoelectrics

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2879 ◽  
Author(s):  
Lazaros Tzounis ◽  
Markos Petousis ◽  
Sotirios Grammatikos ◽  
Nectarios Vidakis
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Seebeck Coefficient ◽  
Morphological Characteristics ◽  
Multiwalled Carbon Nanotube ◽  
Melt Mixing ◽  
Multiwalled Carbon ◽  
Fused Deposition ◽  
3D Printed

Three-dimensional (3D) printing of thermoelectric polymer nanocomposites is reported for the first time employing flexible, stretchable and electrically conductive 3D printable thermoplastic polyurethane (TPU)/multiwalled carbon nanotube (MWCNT) filaments. TPU/MWCNT conductive polymer composites (CPC) have been initially developed employing melt-mixing and extrusion processes. TPU pellets and two different types of MWCNTs, namely the NC-7000 MWCNTs (NC-MWCNT) and Long MWCNTs (L-MWCNT) were used to manufacture TPU/MWCNT nanocomposite filaments with 1.0, 2.5 and 5.0 wt.%. 3D printed thermoelectric TPU/MWCNT nanocomposites were fabricated through a fused deposition modelling (FDM) process. Raman and scanning electron microscopy (SEM) revealed the graphitic nature and morphological characteristics of CNTs. SEM and transmission electron microscopy (TEM) exhibited an excellent CNT nanodispersion in the TPU matrix. Tensile tests showed no significant deterioration of the moduli and strengths for the 3D printed samples compared to the nanocomposites prepared by compression moulding, indicating an excellent interlayer adhesion and mechanical performance of the 3D printed nanocomposites. Electrical and thermoelectric investigations showed that L-MWCNT exhibits 19.8 ± 0.2 µV/K Seebeck coefficient (S) and 8.4 × 103 S/m electrical conductivity (σ), while TPU/L-MWCNT CPCs at 5.0 wt.% exhibited the highest thermoelectric performance (σ = 133.1 S/m, S = 19.8 ± 0.2 µV/K and PF = 0.04 μW/mK2) among TPU/CNT CPCs in the literature. All 3D printed samples exhibited an anisotropic electrical conductivity and the same Seebeck coefficient in the through- and cross-layer printing directions. TPU/MWCNT could act as excellent organic thermoelectric material towards 3D printed thermoelectric generators (TEGs) for potential large-scale energy harvesting applications.

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