Thermal Properties Of Natural Rubber Research Articles

Synergistic effects of soap nut extract and glutaraldehyde on the properties of natural rubber: A waste to wealth approach

This study aimed at the extraction of soap nut fruit to blend with natural rubber as a natural additive. The effectiveness of blending at various blend ratios has been studied in detail. The effects of soap nut extract on the tensile properties, thermal stability, glass transition and crystalline melting temperatures, solvent transport properties, morphology and antibacterial properties were investigated. FTIR was employed to confirm the presence of functional groups and the interaction between both the blend constituents. Enhancement in the tensile and thermal properties of natural rubber was noticed upon the incorporation of soap nut extract. The increased glass transition and crystalline melting temperatures suggests the miscibility of both blend components. Solvent transport study in benzene showed an increasing trend upon the addition of soap nut extract into natural rubber. SEM microphotographs showed a fine and continuous surface morphology in case of the blend when compared to pure natural rubber. Antibacterial studies revealed that the incorporation of soap nut extract makes natural rubber more stable. The blend with 5 % soap nut extract exhibited superior properties than that of the other blend components.

Natural rubber and copper alumina nanocomposite‐based flexible elastomer‐inorganic hybrid systems

AbstractThis work investigates the effect of different loading of copper alumina nanoparticles (Cu‐Al2O3) on the processing characteristics, crystalline, morphological, mechanical, and thermal properties of natural rubber (NR). The effective reinforcement of Cu‐Al2O3 nanoparticles into NR was carried out using a simple and efficient two roll mill mixing technique and the structural changes were systematically analyzed by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscope (SEM), high‐resolution transmission electron microscope (HR‐TEM), differential scanning calorimetry, and thermogravimetric analysis. The FTIR and XRD of NR/Cu‐Al2O3 showed the characteristic absorption bands and the crystalline peaks of Cu‐Al2O3 in the prepared composites. SEM and HR‐TEM showed the uniform distribution of nano Cu‐Al2O3 in the NR matrix. The processing time of the nanocomposites was significantly decreased with the addition of metal oxide nanoparticles, which indicated the reduction in the cost of the fabrication of elastomer product using Cu‐Al2O3 nanoparticles. Mechanical properties such as modulus, tensile strength, hardness, heat build‐up, glass transition temperature, tear properties, abrasion, and thermal stability were greatly enhanced by the reinforcement of Cu‐Al2O3 into the NR matrix. The swelling behavior of composite with respect to different loading of nano‐filler was also investigated in various aromatic solvents. The addition of nanoparticles reduces the solvent uptake of the composite and the maximum solvent resistance was noted for the composite with 5 phr loading.

Grafting of various acrylic monomers on to natural rubber: Effects of glutaraldehyde curing on mechanical and thermo-mechanical properties

Natural rubber (NR) grafted with different acrylic-monomers, namely butyl acrylate (BA), methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA), were prepared via redox polymerization. This aims to enhance the mechanical and thermal properties of pristine NR by using a novel curing system of glutaraldehye (GA). Grafting of acrylic-monomers onto NR molecular chains was clarified using ATR-FTIR and 1H-NMR. It was found that the grafted-NR vulcanizates effectively improved the mechanical properties. Here, NR-g-PBMA showed enhancement in moduli, tensile strength and elongation at break of approximately 100, 280, and 40 %, respectively, when compared to the one without modification. It was also observed that, all the grafted-NR vulcanizates exhibited an improved crosslinking. This was elucidated through the engine oil swelling and the TSSR (i.e. Temperature Scanning Stress Relaxation) measurements. The latter test was also first proposed for characterizing the grafted-NR in terms of mechanical and thermo-mechanical interpretations. The thermogram clearly exhibited that the thermal properties of NR were significantly improved after graft copolymerization owing to the presence of functional groups on the molecular chain which enhanced the intermolecular attraction of the grafted-NR molecules. It can be summarized that two possibilities of interaction were observed: (I) the chemical interaction of GA-Rubber through the CC bonds and through the active ester groups of grafted-NR molecules, and (II) the physical polar-polar interaction through the presence of carbonyl groups of grafted-NR molecules. Thus, the present work is found to be beneficial to the future applications of NR which requires high specific modulus and thermal stability at low strain in case of flexible actuators and sensors. Furthermore, the newly curing technique can be easily used to fabricate article at low temperature with greater ease of processing.

SURFACE MODIFICATION OF NANO TITANIUM DIOXIDE (TiO2) BY CATIONIC SURFACTANTS AND INVESTIGATION OF ITS EFFECT ON THE PROPERTIES OF NATURAL RUBBER (NR) NANOCOMPOSITES

ABSTRACT We investigate the reinforcing effects of both unmodified and surface modified nano titanium dioxide (TiO2) on the cure, mechanical, and thermal properties of natural rubber (NR) nanocomposites. The surface of nano TiO2 is modified by cationic surfactants cetyltrimethylammonium bromide (CTAB) and tetraethylammonium bromide (TEAB). The surface modification of nano TiO2 is characterized by Fourier transform infrared (FTIR) spectra and Field emission scanning electron microscopy (FESEM). The result reveals that surface modified nano TiO2 is much more efficient in improving the resulting properties of NR nanocomposites in comparison with unmodified nano TiO2. The excellent improvement in the properties of surface modified nano TiO2/NR composites is due to the better hydrophobicity and uniform dispersion of modified nano TiO2 within the NR matrix, as confirmed from morphological analysis. CTAB is much more effective than TEAB with respect to the properties of nano TiO2 based NR composites.

Preparation of composites from natural rubber and oil palm empty fruit bunch cellulose: Effect of cellulose morphology on properties

Rubber tree and oil palm are industrial crops cultivated in the same climate and environment. These plants are used to prepare nanocomposites of natural rubber and cellulose from empty fruit bunches, an abundant residue in the palm oil industry. For this study, the cellulose particles were extracted from the bunches and subjected to enzymatic hydrolysis or microfibrillation to produce nanostructured particles. The nanoparticles were blended with natural rubber latex in an aqueous medium, and the mixture was dried. The properties of the nanocomposites were compared to those of pure natural rubber and unprocessed cellulose composites. The mechanical properties of the natural rubber can be modified by the cellulose content and morphology. As a consequence, it is possible to modulate the material properties by changing only the filler morphology. The use of microfibrillated cellulose had stronger reinforcement effects. The thermal properties of natural rubber were not affected by the addition of cellulose.

Preparation of composites from natural rubber and oil palm empty fruit bunch cellulose: Effect of cellulose morphology on properties

Rubber tree and oil palm are industrial crops cultivated in the same climate and environment. These plants are used to prepare nanocomposites of natural rubber and cellulose from empty fruit bunches, an abundant residue in the palm oil industry. For this study, the cellulose particles were extracted from the bunches and subjected to enzymatic hydrolysis or microfibrillation to produce nanostructured particles. The nanoparticles were blended with natural rubber latex in an aqueous medium, and the mixture was dried. The properties of the nanocomposites were compared to those of pure natural rubber and unprocessed cellulose composites. The mechanical properties of the natural rubber can be modified by the cellulose content and morphology. As a consequence, it is possible to modulate the material properties by changing only the filler morphology. The use of microfibrillated cellulose had stronger reinforcement effects. The thermal properties of natural rubber were not affected by the addition of cellulose.

Natural Rubber-Whisker Alumina Fiber Composite Materials for Mechanical and Thermal Insulation Applications

Alumina fiber is a ceramic material used as a dispersed phase or filler to reinforce the mechanical and improve thermal properties of natural rubber via vulcanization process at curing temperature 150°C. The amount of alumina fiber added in natural rubber was varied from 0 to 50 phr on 100 phr of natural rubber in a sulfur curing system. Adding 10 phr alumina fiber affects to obtain the best natural rubber composite samples having good mechanical and thermal properties. Tensile strength, elongation at break, Young’s modulus and thermal conductivity of adding 10 phr whisker alumina fiber encoded NR-Al-10 are equal to 14.38±1.95 MPa, 1038.4±41.45%, 545.63±25.67 MPa and 0.2376±0.0003 W/m.K, respectively, better than those of pure natural rubber compounds without adding alumina fiber. Tensile strength, elongation at break, Young’s modulus and thermal conductivity of natural rubber without adding alumina fiber are equal to 14.06±6.03 MPa, 949.41±52.15%, 496.32±8.54 MPa and 0.2500±0.0003 W/m.K, respectively.

The effect of high purity rice husk silica synthesised using solvent-thermal extraction method on the properties of natural rubber compounds

This work highlights the synthesis of high purity silica from rice husks and the effect of rice husk silica (RHS) loading on the mechanical, physical, and thermal properties of natural rubber (NR) compounds. The RHS was synthesised using the solvent-thermal extraction method, which was adopted from TAPPI T204 (2007) and TAPPI T264 (1997) standards with some modifications. The treatment successfully produced high purity RHS particles, with 99.9% SiO2 content between 100 to 300 nm in size. The high purity RHS was then incorporated in NR compounds at 2, 4, 6, 8, and 10 parts per hundred rubber (phr). Even without any surface modification, the high purity RHS-filled NR compounds showed tremendous improvements in strength-related properties at the optimum loading of 4 phr. In addition, the thermal stability of the NR compounds was remarkably improved with the addition of RHS.

Novel Approaches of Using of Spirulina Platensis in Natural Rubber Based Composites

The aim of this work was to investigate the influence of Spirulina (Spirulina platensis) as a natural filler on the curing characterization, morphology and mechanical, thermomechanical and thermal properties of natural rubber... | Find, read and cite all the research you need on Tech Science Press

Synthesis and thermal properties of natural rubber grafted with poly(2-hydroxyethyl acrylate)

A novel modified natural rubber with grafted poly(2-hydroxyethyl acrylate) (NR-g-PHEA) was synthesized by emulsion polymerization in latex stage. Cumene hydroperoxide and tetraethylene pentamine were used as redox initiators (1:1 M ratio). The influences of reaction temperature, reaction time, initiator concentration and monomer concentration on percent grafting and grafting efficiency were investigated. Transmission electron microscopy was used to observe the NR-g-PHEA particles, which exhibited core-shell morphology. Chemical structure of purified NR-g-PHEA was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The thermal properties were examined by thermogravimetric analysis and by differential scanning calorimetry. The modified NR had improved thermal stability, and the NR-g-PHEA also presented slightly higher glass transition temperature than virgin NR.

Influence of poly(methyl methacrylate) grafted multiwalled carbon nanotubes on the mechanical and thermal properties of natural rubber nanocomposites

In this study, we describe the preparation and characterization of natural rubber nanocomposites filled with poly (methyl methacrylate) grafted multiwalled carbon nanotube. The use of various filler loadings (1, 2, 3, and 5 wt %) and melt blending method was employed. From the results, nanocomposite with 1 phr filler loading showed the optimal tensile strength of 4.92 MaP, while that of the carbon black N330 filled natural rubber with similar filler loading found to be 2.48 MaP. The nanocomposite with optimal tensile strength exhibited a good filler dispersion in the natural rubber matrix, which was depicted by the field emission scanning electron microscopy images. The thermal degradation temperature of the vulcanized neat natural rubber composite was increased from 380℃ to 462℃ with 1 phr filler loading. The polymer modified multiwalled carbon nanotube improved the mechanical and thermal properties of natural rubber, suggesting its potential as reinforcement filler in rubber industry.

PALS and DSC measurements in 8 MeV electron irradiated natural rubber filled with different fillers

The effect of high energy electron irradiation on the microstructure and thermal properties of natural rubber (NR) filled with different fillers at different concentrations are studied. The samples are irradiated with 8 MeV electron beam to a total dose of 100 KGy. The change in free volume size and specific heat due to addition of fillers and irradiation are studied using positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimetry (DSC) respectively. The Positron lifetime spectra are de-convoluted into two components. The longer lived component [Formula: see text] signifies the pick-off annihilation of ortho-positronium (o-Ps) at free volume site which may be related to the radius of the free volume holes. It is observed that the specific heat [Formula: see text] and free volume size are all affected by both irradiation and addition of fillers.

Monitoramento das Propriedades Térmicas das Borrachas Naturais de Novos Clones: IAC 301 e IAC 303

Natural rubber (NR) tapped from three clones of the rubber tree [Heveabrasiliensis (Willd. ex Adr. de Juss. Muell.-Arg.)] over a seven month period was obtained by coagulation of lattices with 10% acid acetic and dried at 65 °C. TG-DTG curves were used to monitor thermal properties of NR. The TG-DTG results indicated very small differences among the clones and tappings, except in the value of Tf-T0, which indicated that the IAC 301 clone suffered the fastest thermal degradation, during decomposition of the dried, raw NR. There was no significant difference in Tg values among clones and tappings.

Processing–Morphology–Property Relationships and Composite Theory Analysis of Reduced Graphene Oxide/Natural Rubber Nanocomposites

Dispersion of reduced graphene oxide (RG-O) into natural rubber (NR) was found to dramatically enhance the mechanical, electrical, and thermal properties of NR. However, property improvements were strongly dependent upon the processing history and nanocomposite morphology. Co-coagulating a stable RG-O suspension with NR latex afforded a weblike morphology consisting of platelet networks between the latex particles, while two-roll mill processing broke down this structure, yielding a homogeneous and improved dispersion. The physical properties of RG-O/NR vulcanizates with both morphologies were compared over a range of loadings; it was found that the network morphology was highly beneficial for thermal and electrical conductivity properties and greatly increased stiffness but was detrimental to elongation. A detailed comparative analysis of composite models found the Guth equation gave excellent fit to modulus data of the milled samples when taking the shape factor as equal to the platelet aspect ratio qua...

THERMAL DEGRADATION OF NATURAL RUBBER/STYRENE BUTADIENE RUBBER LATEX BLENDS BY THERMOGRAVIMETRIC METHOD

Thermal properties of natural rubber (NR)/styrene butadiene rubber (SBR) latex blends made from latex blending have been investigated using thermogravimetric analysis. It was found that the initial degradation temperature of NR is lower than SBR, and on addition of SBR, the degradation temperature is increased, indicating increased thermal stability of the blend. The main degradation products of NR contain isoprene and dipentene and that of SBR contains a large number of products like 4-vinyl cyclohexene, styrene, methylbenzene, and so forth. In addition to that, the temperature at which 50% and 75% degradation of NR occurs is increased upon the addition of SBR. Vulcanization increased the thermal stability of NR/SBR blends slightly. The activation energies for the degradation of the blends are higher than that of the homopolymers.

Thermal properties of natural rubber versus temperature and pressure

The thermal conductivity λ and the heat capacity per unit volume ρcp were determined by the transient hot-wire method at pressures up to 1.0 GPa and in the temperature range 130–340 K. Specimens were cold-pressed pure rubber and hot-pressed rubber containing 3.7% sulphur. The vulcanized variety was found to have a higher glass transition temperature Tg at all pressures. Our value of Tg at atmospheric pressure is higher by 23 K than the previously reported values from quasistatic experiments, which can be accounted for by the relaxation time of the excitation mode. The derivative of the transition temperature ∂Tg/∂P was found to decrease with increasing pressure for both samples, as predicted by a recent theory. The thermal-expansion coefficient was determined under pressure from the temperature response to adiabatic pressurization using the heat-capacity data.

Calorific and Thermal Properties of Natural Rubber in the Oriented and Non-Oriented States

Abstract The structural characteristics of high polymers and the sharp dependence of their properties on the physical state create a need for a detailed study of these materials in the region where their physical state undergoes a qualitative change. Besides, a study of the phase transitions of high polymers which crystallize is of independent interest. The study of the transition of natural rubber from the oriented crystalline state to the non-oriented amorphous state was the problem of this work. The determination of calorific and thermal properties in the transition region was adopted as the method of investigation. It should be noted that, for rubbers, these properties have been studied to a much lesser extent than have the other thermodynamic properties, particularly the mechanical properties. In order to obtain crystalline rubber, strips of smoked sheet were subjected to repeated rapid stretching at 50°, followed by cooling of the stretched samples to 12–14° C. The stress applied to the rubber during stretching overcomes the deorienting effect of the thermal motion, which impedes the crystallization of non-deformed rubber. At the same time, the heating employed promotes a more complete straightening of the chains since, during heating, intermolecular action diminishes and the chaotically-grouped oriented portions of the macromolecules present in the samples are disrupted. Rapid cooling of the oriented rubber, obtained under such conditions, to temperatures below the melting point of the crystals which formed led to the preservation of the physical state, which was distinguished by an increase of the crystalline phase content, and by a higher degree of orientation, compared with the state of rubber crystallized during the same time by lowering the temperature without stretching. On an average, the extent of stretching amounted to 1400 per cent of the original length.