Characterization of the Reversion Process in Accelerated Sulfur Curing of Natural Rubber

1981 ◽  
Vol 54 (4) ◽  
pp. 734-750 ◽  
Author(s):  
C. H. Chen ◽  
J. L. Koenig ◽  
J. R. Shelton ◽  
E. A. Collins
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Structural Basis ◽  
Rubber Vulcanizate ◽  
Chemically Induced ◽  
Vulcanization Process ◽  
Sulfur Curing

Abstract From studies of a series of accelerated sulfur vulcanizations of natural rubber, the structural basis of the reversion in macroscopic physical-mechanical properties has been determined. The amount of chemically induced trans-methine butadiene-like structure increases as the reversion process proceeds. When there is no observable reversion, there is no detectable trans-methine butadiene-like structure. The presence of the trans-methine butadiene-like structure is detrimental to the properties of the natural rubber vulcanizate. The vulcanization process involves two competing processes, namely, crosslinking and desulfuration. The latter process produces the trans-methine structure which is responsible for the reversion in properties.

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.

Preparation and Characterization of Nanocrystalline Cellulose/Natural Rubber (NCC/Nr) Composites

2013 ◽  
Vol 712-715 ◽  
pp. 111-114 ◽  
Author(s):  
Tian Ming Gao ◽  
Mao Fang Huang ◽  
Rui Hong Xie ◽  
Hong Lian Chen
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Nanocrystalline Cellulose ◽  
Rubber Latex ◽  
Dynamic Mechanical ◽  
Surface Modified

Surface modified nanocrystalline cellulose (NCC) was prepared by silicon-69, and then blended into natural rubber latex to prepare nanocomposites. The nanocomposites properties of tensile properties, tear strength, morphology and thermal dynamic mechanical properties were measured by mechanical property testing, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA), respectively. The results showed that modified NCC is homogeneously distributed throughout NR matrix, which leads to the enhancement on mechanical properties. Moreover, the storage modulus (E) of modified nanocellulose filled NR is higher than unmodified nanocellulose filled NR, and the tanδ is reversed.

Effects of Tourmaline Concentration on Natural Rubber Foam

2019 ◽  
Vol 801 ◽  
pp. 127-132
Author(s):  
Phittinun Chayaphan ◽  
Rapeephun Dangtungee
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Skin Temperature ◽  
Natural Rubber Latex ◽  
High Density ◽  
Temperature Analysis ◽  
Rubber Latex ◽  
Potassium Oleate ◽  
Sulfur Curing ◽  
Batch Foaming

Natural rubber foam/tourmaline composite was prepared from natural rubber latex and vulcanized by sulfur curing system. Tourmaline powder was dispersed in potassium oleate before foaming production. The batch foaming production was used in this research. In order to investigate the effects of tourmaline concentration in natural rubber foam, mechanical properties, microstructure, and thermal skin temperature analysis were performed. Increasing of tourmaline concentration affected on high density and small microstructure of natural rubber foam, and the increasing of skin temperature. EDS result confirmed the good distribution of tourmaline powder in natural foam.

Properties of Thermoplastic Natural Rubber (TPNR): Influence of Polypropylene Grades on TPNR Properties

2013 ◽  
Vol 844 ◽  
pp. 127-130 ◽  
Author(s):  
Chanida Manleh ◽  
Charoen Nakason ◽  
Natinee Lopattananon ◽  
Azizon Kaesaman
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Rubber Particle ◽  
Complex Viscosity ◽  
Morphological Properties ◽  
Dynamic Vulcanization ◽  
Thermoplastic Natural Rubber ◽  
Pp Blends ◽  
Vulcanization Process

Thermoplastic vulcanizate (TPV) based on natural rubber (NR) and polypropylene (PP) blends were successfully prepared through a dynamic vulcanization process using Brabender Plastograph EC Plus with a rotor speed of 60 rpm at 180°C. Sulfur vulcanization system was used to cure rubber phase in the TPVs. Three grades of PP (i.e., PP700J, HP553R and HP544T) were used to blend with NR at a fixed blend ratio of NR/PP = 60/40. The mechanical properties, crosslink density, complex viscosity and morphological properties of the blends were examined. The results revealed that the dynamically cured NR/PP700J samples showed the best mechanical properties because of higher crosslink density and smaller rubber particle size when compared with those of the blends combined with HP553R and HP544T. Furthermore, the complex viscosity of the TPVs was highest for the blends with PP700J.

Effects of Thermal Aging on The Mechanical Properties of Natural Rubber

2003 ◽  
Vol 76 (4) ◽  
pp. 785-802 ◽  
Author(s):  
Joseph T. South ◽  
Scott W. Case ◽  
Kenneth L. Reifsnider
Keyword(s):  
Mechanical Properties ◽  
Thermal Degradation ◽  
Natural Rubber ◽  
Thermal Aging ◽  
Master Curve ◽  
Dynamic Mechanical Properties ◽  
Rubber Compound ◽  
Dynamic Mechanical ◽  
Rubber Vulcanizate

Abstract The focus of this research was to investigate the effect of thermal degradation upon the mechanical properties of a natural rubber compound. We examined both the quasi-static and dynamic mechanical properties of a natural rubber vulcanizate which had been subjected to isothermal, anaerobic aging. The thermal aging was conducted between the temperatures of 80 °C and 120 °C for times ranging from 3 to 24 days. The effect of thermal degradation was measured using the changes in the crosslink distribution of the vulcanizates as functions of time at temperature. A master curve relationship between the crosslink distribution of the vulcanizates due to thermal degradation and the static and dynamic mechanical properties has been developed. It was found that the both the quasi-static and dynamic mechanical properties correlated with the percentage of poly and monosulfidic crosslinks, where in general higher levels of polysulfidic crosslink gave rise to the highest mechanical properties.

scholarly journals Development and Characterization of Bacterial Cellulose Reinforced with Natural Rubber

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2323 ◽  
Author(s):  
Kornkamol Potivara ◽  
Muenduen Phisalaphong
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Bacterial Cellulose ◽  
Polar Solvents ◽  
High Mechanical Strength ◽  
Elongation At Break ◽  
Hydrocarbon Polymer ◽  
Structural Networks ◽  
Film Characteristics

Films of bacterial cellulose (BC) reinforced by natural rubber (NR) with remarkably high mechanical strength were developed by combining the prominent mechanical properties of multilayer BC nanofibrous structural networks and the high elastic hydrocarbon polymer of NR. BC pellicle was immersed in a diluted NR latex (NRL) suspension in the presence of ethanol aqueous solution. Effects of NRL concentrations (0.5%–10% dry rubber content, DRC) and immersion temperatures (30–70 °C) on the film characteristics were studied. It was revealed that the combination of nanocellulose fibrous networks and NR polymer provided a synergistic effect on the mechanical properties of NR–BC films. In comparison with BC films, the tensile strength and elongation at break of the NR–BC films were considerably improved ~4-fold. The NR–BC films also exhibited improved water resistance over that of BC films and possessed a high resistance to non-polar solvents such as toluene. NR–BC films were biodegradable and could be degraded completely within 5–6 weeks in soil.

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