Potential Use of Petroleum-based Sulfur in Rubber Industry

AbstractPotential use of petroleum-based sulfur generally classified as a by-product from refinery process is investigated as vulcanizing agent in rubber, and compared with commercial rhombic sulfur. Styrene-butadiene rubber (SBR) and nitrile rubber (NBR) are used as rubber matrices. Results obtained show that, between 2 types of sulfurs, the SBR system reveals similarity in cure behaviors whereas the NBR system demonstrates faster cure behavior when vulcanized by petroleum-based sulfur. However, rheological properties, mechanical properties, and dynamic mechanical properties of both rubbers show comparable results regardless of sulfur type. The results suggest the strong potential utilization of petroleum-based sulfur as vulcanizing agent as an alternative to the commercial rhombic sulfur usually used in rubber vulcanization

Influence of Carbon Black/Silica Hybrid Ratio on Properties of Passenger Car Tire Sidewall

Influence of carbon black (CB)/precipitated silica (SiO2) hybrid ratio on properties of a passenger car tire (PCT) sidewall based on natural rubber (NR) and butadiene rubber (BR) blend was investigated. Rubbers filled with various hybrid filler ratios at a constant loading of 50 phr were prepared and tested. The filler reinforcement efficiency in association with crucial properties of the tire sidewall were of interest. Results show the enhanced rubber–filler interaction with increasing SiO2 fraction leading to the improvement in many vulcanizate properties including hardness, tensile strength, tear strength and fatigue resistance, at the expense of cure efficiency and hysteretic behaviors (i.e., reduced heat build-up resistance and increased dynamic set). The results also suggest the improvement in tire sidewall performance of the NR/BR vulcanizates reinforced with CB/SiO2 hybrid filler, compared to that of the CB-filled vulcanizate

Effects of Blend Ratio and SBR Type on Properties of Carbon Black-Filled and Silica-Filled SBR/BR Tire Tread Compounds

This work aimed at investigating the effects of blend ratio between styrene butadiene rubber (SBR) and butadiene rubber (BR) and SBR type (E-SBR and S-SBR) on properties of SBR/BR tire tread compounds. Influences of these parameters on properties of the tread compounds reinforced by 80 parts per hundred rubber (phr) of carbon black (CB) and silica were also compared. Results reveal that hardness, strengths, and wet grip efficiency were impaired whereas rolling resistance was improved with increasing BR proportion. Surprisingly, the presence of BR imparted poorer abrasion resistance in most systems, except for the CB-filled E-SBR system in which an enhanced abrasion resistance was observed. Obviously, S-SBR gave superior properties (tire performance) compared to E-SBR, particularly obvious in the silica-filled system. Compared with CB, silica gave comparable strengths, better wet grip efficiency, and lower rolling resistance. Carbon black, however, offered greater abrasion resistance than silica

Measurement and modelling of the influence of hysteresis on the internal temperature rise of rubber components

Finite element analysis (FEA) is a numerical analysis method which is used widely to obtain approximate solutions in many fields of engineering. With sophisticated computer hardware and software. FEA has recently become an effective tool in the design of rubber components. [Continues.

Reinforcement of Multiwalled Carbon Nanotube in Nitrile Rubber: In Comparison with Carbon Black, Conductive Carbon Black, and Precipitated Silica

The properties of nitrile rubber (NBR) reinforced by multiwalled carbon nanotube (MWCNT), conductive carbon black (CCB), carbon black (CB), and precipitated silica (PSi) were investigated via viscoelastic behavior, bound rubber content, electrical properties, cross-link density, and mechanical properties. The filler content was varied from 0 to 15 phr. MWCNT shows the greatest magnitude of reinforcement considered in terms of tensile strength, modulus, hardness, and abrasion resistance followed by CCB, CB, and PSi. The MWCNT filled system also exhibits extremely high levels of filler network and trapped rubber even at relatively low loading (5 phr) leading to high electrical properties and poor dynamic mechanical properties. Although CCB possesses the highest specific surface area, it gives lower level of filler network than MWCNT and also gives the highest elongation at break among all fillers. Both CB and PSi show comparable degree of reinforcement which is considerably lower than CCB and MWCNT

New Vegetable Oils with Different Fatty Acids on Natural Rubber Composite Properties

Owing to the toxicity of polycyclic aromatic (PCA) oils, much attention has been paid to the replacement of PCA oils by other nontoxic oils. This paper reports comparative study of the effects of new vegetable oils, i.e., Moringa oil (MO) and Niger oil (NO), on rheological, physical and dynamic properties of silica–filled natural rubber composite (NRC), in comparison with petroleum–based naphthenic oil (NTO). The results reveal that MO and NO exhibit higher thermal stability and better processability than NTO. Cure characteristics of the rubber compounds are not significantly affected by the oil type. It is also found that the NRCs containing MO or NO have better tensile strength and lower dynamic energy loss than the NRCs containing NTO. This may be because both MO and NO improve filler dispersion to a greater extent than NTO as supported by storage modulus and scanning electron microscopy results. Consequently, the present study suggests that MO and NO could be used as the alternative non–toxic oils for NRC without any loss of the properties evaluated

Effects of chitosan contents on latex properties and physical properties of natural rubber latex/chitosan composites

RMUTP Research Journal, Vol. 12, No. 1, (Jan-Jun. 2018), p. 172-182In this study, natural rubber latex/chitosan (NRL/CT) composites were prepared by latex mixing. The effects of chitosan on latex properties and physical Properties of NRL/CT composite films were focused. It was found that there was no significant change in the latex properties with increasing CT content. Increasing CT contents of 0.5 to 8.0 phr caused the rising of 300 % modulus of the NRL/CT composite whereas the opposite trend was found for tensile strength and elongation at break. The antimicrobial efficacy of the chitosan-incorporated rubber was slightly enhanced from that of the non-chitosan rubber. By comprehensive consideration, CT content suitable for antibacterial gloves according to Thai industrial standards (TIS 1056-1: 2013) was 1 phr. For other latex products that require high modulus and antibacterial activity such as tubing, pillow foam, rubber nipple and catheter, CT could be used at higher contents from 2 to 4 phr.Rajamangala University of Technology Phra Nakho

Application of Tamarind Shell as a Green Additive in Natural Rubber

The feasibility of using tamarind shell as an eco-friendly additive in natural rubber (NR) was studied. Tamarind shell powder (TSP) was prepared with different particle size ranges before being characterized by various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), elemental analysis, etc. The results of the FTIR and elemental analysis confirmed that TSP was mainly composed of amino acids (proteins), celluloses, and tannins. The thermal analysis revealed that TSP contained approximately 9% moisture, and its main constituents were stable up to 200 °C, which is higher than the normal processing temperature of rubber products. The addition of TSP to NR led to reductions in scorch time and cure time due to the presence of moisture and proteins. This phenomenon was more obvious with the decrease in TSP’s particle size. Even though the small addition of TSP (≤10 phr) did not cause any change in hardness, it significantly impaired the mechanical properties of the rubber vulcanizates, particularly tensile strength, elongation at break, and abrasion resistance. Such deterioration depended greatly on the TSP particle size, i.e., the finest particles (S-TSP) showed the least deterioration of mechanical properties. In summary, TSP can be considered a low-cost, eco-friendly bio-additive for rubbers. Nevertheless, it must be used with great care to avoid undesirable impacts on mechanical properties

Film and latex forms of silica-reinforced natural rubber composite vulcanized using electron beam irradiation

A thorough study was undertaken of the synthesis of natural rubber-silica treated with bis-(3-triethoxysilylpropyl) tetrasulfane (NR/TSi) vulcanized using electron beam irradiation (EB) and sulfur by varying the EB dose. The surface treatment of silica was confirmed using Fourier-transform infrared spectroscopy and scanning electron microscopy images. Composites were cast and vulcanized in film and latex forms compared with sulfur vulcanization. Investigation covered the mechanical properties, thermal stability, swelling resistance, and degradation under heat and humidity testing of the NR/TSi composites. It was found that the TSi had great dispersal in the NR matrix. TSi in NR matrix had a positive effect on mechanical properties, swelling in water and toluene, and thermal stability. Increasing the radiation intensity up to 250 kGy led to superior mechanical properties but for further increase in the radiation intensity, the tensile strength dropped. Degradation under thermal and humidity testing showed that the un-vulcanized composite had higher physical degradation than the vulcanized samples. Therefore, NR/TSi vulcanized using 200 kGy EB vulcanized in latex form had the greatest mechanical properties for various applications without producing any residual vulcanizing agent