Theoretical Explanation of Vulcanisation of Latex of Landolphia Owariensis (P. Beauv) Using Sodium Sulphite (Na2SO3) Solution Under low Temperature (original) (raw)
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Vulcanization Kinetics of Natural Rubber Based On Free Sulfur Determination
Indonesian Journal of Chemistry, 2013
The determination of free sulfur in the rubber vulcanizates provided significant representation of vulcanization reaction. In this research, the effects of vulcanization temperature, the mixing method of carbon black into rubber, the ingredients mixing sequence and the type of carbon black were studied on masticated and milled natural rubber in which the reaction was observed by un-reacted sulfur determination. The results showed that higher vulcanization temperature provided faster vulcanization reaction and greater reaction rate constant. Similarly, the mixing sequence of ingredient and carbon black into rubber influenced the rate of vulcanization reaction. The subsequent ingredients mixing sequence, in this case, resulted in higher vulcanization rate compared to that of the simultaneous one. However, the mixing method of carbon black into rubber brought small effect on the rate of vulcanization reaction. The type of carbon black applied was observed to influence the reaction rate...
Express Polymer Letters, 2021
This work presents a simple processing way to vulcanize natural rubber (NR) using glutaraldehyde (GA) as a curing agent at low temperature. The effect of different protein contents of NR latex on the resulting properties of the NR vulcanizates is examined in this paper. The protein contents in different NR latex, including creamed-NR (CreNR), centrifuged-NR (CenNR), and synthetic-NR (SynNR) latexes, were successfully analyzed. It was found that CreNR has the highest protein content, followed by CenNR and SynNR, respectively. The influence of protein contents in NR latex on crosslink density, mechanical properties, and thermal stability of the cured NR were investigated and compared. Temperature scanning stress relaxation (TSSR) technique was used to examine the crosslinking among GA and protein molecules, which has inter-particle interactions with NR molecular chain. This was compared with the conventional swelling experiments used in determining the swelling ratio. It is found that the mechanical properties, thermal stability, and the crosslinking density data are strongly related to the protein content in the NR latex, i.e., CreNR > CenNR >Syn NR. This is attributed to the protein strong contacts of the protein content to the NR chain and its ability to propagate chemical crosslinking with GA molecules. Therefore, the protein causes new linkages between rubber molecules through GA.
A REVIEW PAPER ON VULCANIZATION OF RUBBER AND IT’S PROPERTIES
Natural rubber is composed of long polymer molecules and is sticky in nature. It is obtained from trees in the form of latex. Elasticity as well as tensile strength of natural rubber is low. So, vulcanization is done to enhance the properties of natural rubber. Generally Sulphur along with additives is added to rubber and heated up. This will increase the properties of rubber. Vulcanized rubber gets application in various industries and products such as conveyor belts, pulleys, tires, vehicle mats, etc. This paper appraises the data regarding the process of vulcanization which improves desirable properties of rubber. Keywords: Natural Rubber, Vulcanization, Rubber.
Preparation and Properties of Organokaolin Natural Rubber Latex Base Vulcanisate
Advances in Materials, 2015
Natural rubber (NR) latex-organokaolin compounds have been investigated. The intercalated kaolin (100% CEC-CTAB of clay) was used in aqueous rubber latex dispersion, from which a coagulum was obtained. The coagulum was used in natural rubber compounds and evaluated for its cure: scorch; t s 1, optimum cure; t 90 min, minimum (ML) and maximum (MH) torque and mechano-physical properties viz: M100, M300, EB (%), hardness and abrasion in mg/1000 rev. The scorch and optimum cure indicated a progressive drop with addition of organokaolin in natural rubber latex based compounds. Vulcanisate mechanical properties generally showed increase as organokaolin loading increased. A correlation between the measure of extent of vulcanization (MH-ML) and properties such as tensile strength, elongation at break, abrasion and hardness showed that the extent of crosslinking as a result of rubber-filler interaction of the natural rubber based compounds increased as organokaolin loading increased.
Advances in Materials Science and Engineering, 2016
Maillard reaction in Natural Rubber (NR) latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2) in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and attenuated total reflection infrared (ATR-IR) spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (P0), plasticity retention index (PRI), Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out.
Natural Rubber Latex - Origin, Specification and Application
IntechOpen eBooks, 2023
The chapter contains information about the origin of natural rubber latex (NRL) (Hevea brasiliensis) and the processing of field latex, considering quality changes occurring during the preparation of raw materials for distribution. The main types of concentrated natural rubber latex are described. A specification of natural rubber latex (NRL) in terms of key parameters tested by manufacturers and customers is presented. Test methods for verifying if the material meets the requirements of ISO 2004 and internal specifications are described based on standards and commonly used techniques. The next subject touched in the chapter is prevulcanization as the processing of concentrated latex with a change of its properties. One of the main industrial applications of NRL as prevulcanized latex (PV) is the production of dipped goods like gloves or balloons. Currently, some trends and challenges relate to sustainability issues are presented (carbon footprint, FSC).
A study on the impact of the bark camel's foot " Piliostigmathonningii " on the physico-mechanical properties of natural rubber vulcanizate when used as filler has been carried out. Laboratory scale two roll mill was used to compound five different formulations of the natural rubber and the camel's foot bark filler according to the following ratios in grams: 100/0, 70/30, 60/40, 50/50, and 40/60 respectively. From the compounded formulations; test samples were prepared using the laboratory scale hydraulic press machine. Each prepared composite sample was tested for tensile-strength, elongation at break, hardness, abrasion and compression properties, and the result obtained showed that the tensile strength of the vulcanizate increased with increase in filler loading up till 50% of the natural rubber content but decreased when the filler is beyond that. The elongation at break decreased with the control sample having the highest elongation. The hardness of thevulcanizate increased with increase in filler loading. The abrasion resistance did not follow any consistent trend in particular. The compression-set was found to be decreasing with increase in filler loading.
Effect of Stearic Acid Level on the Physical Properties of Natural Rubber Vulcanisate
An investigation was carried out comparing seven different natural rubber formulations, in each case stearic acid level used varied from 0.00 pphr to 6.00 pphr. Vulcanizing at a temperature of 165 0 C for 5 minutes at a pressure of 300 psi, the various compounded formulations were cured. The physical properties viz: hardness, tensile strength, modulus, compression set, elongation at break and abrasion resistance were evaluated. The results obtained are of the view that hardness and compression set increased with an increase in stearic acid levels. Tensile strength and modulus also show an increase with stearic acid level only up to a level of 4.0 pphr. Above this, there is a noticeable drop in both properties. Abrasion resistance decreases with an increase in stearic acid level up to a level of 3.0 pphr, but above this there is a remarkable increase in abrasion resistance. The various results show that stearic acid has a remarked effect on the physical properties of natural rubber vulcanisate. (
Design and analysis of experiments in silica filled natural rubber compounds—effect of castor oil
Polymer Testing, 2003
The potential of castor oil fatty acid as an activator for the vulcanization reaction in silica filled natural rubber (NR) compounds was investigated. Design and analysis of experiments were carried out by keeping constant the concentrations of silica and the other ingredients while the amounts of stearic acid, castor oil and poly(ethylene glycol) were varied. A conventional vulcanization system (CV) was chosen and cure studies were carried out on a TI-100 oscillating disk rheometer at 150, 160 and 170°C. The overall rates and the apparent activation energies for the vulcanization process were calculated for each compound, assuming that vulcanization follows first-order kinetics. The results show that the simple addition of castor oil does not significantly change the vulcanization process.