ORIGIN OF ENERGETIC ELASTICITY AND ENTROPIC ELASTICITY OF NATURAL RUBBER WITH NANODIAMOND NANOMATRIX STRUCTURE

2021 ◽  
Author(s):  
Asangi Gannoruwa ◽  
Yuanbing Zhou ◽  
Kenichiro Kosugi ◽  
Yoshimasa Yamamoto ◽  
Seiichi Kawahara
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Complex Modulus ◽  
Three Dimensional ◽  
Dynamic Mechanical Properties ◽  
Scanning Calorimetry ◽  
Electron Microscopies ◽  
Entropic Elasticity ◽  
Bound Rubber ◽  
Nanomatrix Structure

ABSTRACT The origin of energetic elasticity in conjunction with the entropic elasticity for natural rubber with a nanodiamond nanomatrix structure was investigated in terms of bound rubber formed between nanodiamonds, based on the interaction between natural rubber and nanodiamonds inside the nanomatrix. The natural rubber with a nanodiamond nanomatrix structure was prepared by reacting nanodiamonds with deproteinized natural rubber in the presence of tert-butylhydroperoxide/tetraethylenepentamine at 30 °C in the latex stage followed by drying. Morphology of the products was observed by two-dimensional and three-dimensional transmission electron microscopies. The effect of bound rubber on the mechanical properties of the products was investigated by measurements of the dynamic mechanical properties and differential scanning calorimetry. The contribution of bound rubber was estimated by combining the Takayanagi equation and modified Guth–Gold equation. A significant increase in complex modulus was attributed to the effect of the bound rubber.

Mechanochemical Devulcanization of Vulcanized Gum Natural Rubber

2005 ◽  
Vol 21 (3) ◽  
pp. 183-199
Author(s):  
G.K. Jana ◽  
C.K. Das
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Three Dimensional ◽  
Elongation At Break ◽  
Tear Strength ◽  
Vulcanized Rubber ◽  
Dimensional Network ◽  
Polymeric Chains ◽  
Cure Time

De-vulcanization of vulcanized elastomers represents a great challenge because of their three-dimensional network structure. Sulfur-cured gum natural rubbers containing three different sulfur/accelerator ratios were de-vulcanized by thio-acids. The process was carried out at 90 °C for 10 minutes in an open two-roll cracker-cum-mixing mill. Two concentrations of de-vulcanizing agent were tried in order to study the cleavage of the sulfidic bonds. The mechanical properties of the re-vulcanized rubber (like tensile strength, modulus, tear strength and elongation at break) were improved with increasing concentrations of de-vulcanizing agent, because the crosslink density increased. A decrease in scorch time and in optimum cure time and an increase in the state of cure were observed when vulcanized rubber was treated with high amounts of de-vulcanizing agent. The temperature of onset of degradation was also increased with increasing concentration of thio-acid. DMA analysis revealed that the storage modulus increased on re-vulcanization. From IR spectroscopy it was observed that oxidation of the main polymeric chains did not occur at the time of high temperature milling. Over 80% retention of the original mechanical properties (like tensile strength, modulus, tear strength and elongation at break) of the vulcanized natural rubber was achieved by this mechanochemical process.

scholarly journals Dynamic Mechanical Properties of Vietnam Modified Natural Rubber via Grafting with Styrene

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
T. A. Dung ◽  
N. T. Nhan ◽  
N. T. Thuong ◽  
D. Q. Viet ◽  
N. H. Tung ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Graft Copolymer ◽  
Graft Copolymerization ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Tert Butyl Hydroperoxide ◽  
Wide Range ◽  
Redox Initiator ◽  
Tetraethylene Pentamine

The dynamic mechanical behavior of modified deproteinized natural rubber (DPNR) prepared by graft copolymerization with various styrene contents was investigated at a wide range of temperatures. Graft copolymerization of styrene onto DPNR was performed in latex stage using tert-butyl hydroperoxide (TBHPO) and tetraethylene pentamine (TEPA) as redox initiator. The mechanical properties were measured by tensile test and the viscoelastic properties of the resulting graft copolymers at wide range of temperature and frequency were investigated. It was found that the tensile strength depends on the grafted polystyrene; meanwhile the dynamic mechanical properties of the modification of DPNR meaningfully improved with the increasing of both homopolystyrene and grafted polystyrene compared to DPNR. The dynamic mechanical properties of graft copolymer over a large time scale were studied by constructing the master curves. The value of bT has been used to prove the energetic and entropic elasticity of the graft copolymer.

Thermal stability and dynamic mechanical behavior of functional multiphase boride ceramics/epoxy composites

2019 ◽  
Vol 39 (6) ◽  
pp. 508-514
Author(s):  
Yannan He ◽  
Zhiqiang Yu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Element Analysis ◽  
Reaction Heat ◽  
Dynamic Mechanical

Abstract The thermal and dynamic mechanical properties of epoxy composites filled with zirconium diboride/nano-alumina (ZrB2/Al2O3) multiphase particles were investigated by means of differential scanning calorimetry, dynamic thermo-mechanical analysis, and numerical simulation. ZrB2/Al2O3 particles were surface organic functional modified by γ-glycidoxypropyltrimethoxysilane for the improvement of their dispersity in epoxy matrix. The results indicated that the curing exotherm of epoxy resin decreased significantly due to the addition of ZrB2/Al2O3 multiphase particles. In comparison to the composites filled with unmodified particles, the modified multiphase particles made the corresponding filling composites exhibit lower curing reaction heat, lower loss modulus, and higher storage modulus. Generally speaking, the composites filled with 5 wt% modified multiphase particles presented the best thermal stability and thermo-mechanical properties due to the better filler-matrix interfacial compatibility and the uniform dispersity of modified particles. Finite element analysis also suggested that the introduction of modified ZrB2/Al2O3 multiphase particles increased the stiffness of the corresponding composites.

Morphology and Mechanical Properties of NiZn Ferrite/Thermoplastic Natural Rubber Composite

2014 ◽  
Vol 925 ◽  
pp. 308-312 ◽  
Author(s):  
Mou'ad A. Tarawneh ◽  
Sahrim Haji Ahmad ◽  
Yu Li Jiun ◽  
Radwan Dweiri ◽  
Ibrahim N. Hassan
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Mechanical Test ◽  
Polymer Nanocomposite ◽  
Dynamic Mechanical Properties ◽  
Filler Loading ◽  
Rubber Matrix ◽  
Dynamic Mechanical ◽  
Blending Method ◽  
Thermoplastic Natural Rubber

In this paper the polymer nanocomposite of nickel zinc (NiZn) ferrite nanoparticles incorporated into the thermoplastic natural rubber nanocomposite (TPNR) were prepared via melt blending method. The effect of different NiZn loading (2-10 wt%) on morphology, tensile and dynamic mechanical properties of the obtained composites was investigated. It was found that NiZn ferrite is well dispersed in the thermoplastic natural rubber matrix. The tensile results indicated that filler loading has improved the tensile strength and Youngs modulus of the nanocomposite. However, the elongation at break decreased with increasing the percentage of NiZn. Dynamic mechanical test showed that the highest storage modulus is at 8 wt% filler. Any further increment of the filler content leads to the formation of agglomerate hence affecting the properties. The Scanning electron micrograph (SEM) micrographs reveal aspect ratio and filler orientation in the TPNR matrix also strongly promoted interfacial adhesion between the filler and the matrix to control its properties.

scholarly journals Study on dynamic mechanical properties of a nylon-like polyester tire cord

2019 ◽  
Vol 14 ◽  
pp. 155892501986880 ◽  
Author(s):  
Liyong Tian ◽  
Di Wang ◽  
Qufu Wei
Keyword(s):  
Mechanical Properties ◽  
Complex Modulus ◽  
Nylon 6 ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Vital Role ◽  
Tire Cord ◽  
Synthetic Fibers ◽  
Dynamic Mechanical ◽  
Polyester Cord

Tires might be the first technically significant composite out of rubber and play a vital role in the overall performance of a car. The essential functions of a tire rely to a great extent on the properties of tire cords. Polyester and nylon cords make up the majority of synthetic fibers used in tires. A new kind of polyester cord has been developed combining the performance characteristics of both polyester and nylon cords. This article examines the dynamic mechanical properties of this nylon-like polyester tire cord by adopting dynamic mechanical analysis, Instron, and DISC fatigue experiments, as well as its dynamic adhesion property using flex fatigue experiment. It demonstrated that the dynamic complex modulus of the nylon-like polyester cord was higher than that of nylon 6 cord but lower than that of standard polyester cord, which was a favorable characteristic when it came to replacing nylon 6 cord with nylon-like polyester cord in tires. Under cyclic loading, hysteresis loss of nylon 6 cord > nylon 66 cord > nylon-like polyester cord > standard polyester cord was observed. In the DISC experiment, nylon-like polyester had a similar compression resistance property to that of nylon 6 cord. At a temperature below 85°C, nylon-like polyester cord maintained roughly the same level of residual ratio of dynamic adhesion, but beyond this temperature point, nylon 6 exhibited a better performance.

The Structure of the System: Filler Rubber. An Electron-Microscopic Study

1954 ◽  
Vol 27 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Friedrich Endter
Keyword(s):  
Natural Rubber ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Three Dimensional ◽  
Electron Microscopic ◽  
Rubber Mixture ◽  
Dimensional Network ◽  
Bound Rubber ◽  
Microscopic Investigations

Abstract Electron microscopic investigations of the benzene-extraction residues of filler-natural rubber mixtures which are used for the determination of bound rubber, give a pattern of a three-dimensional network consisting of filler and bound rubber. The unchanged benzene-soluble rubber is present in the interstices of the network in the untreated filler-rubber mixture.

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