The objective of the present study was to promote a better understanding of the rubber yield of young progenies of Hevea brasiliensis evaluating the stability and the repeatability of early rubber yield test employed in a genetic breeding programme. The genetic material consisted of 30 open pollination progenies evaluated in the Colina county, São Paulo state, Brazil, in a randomised block design.

Natural rubber (NR) contains cis-1,4-polyisoprene as well as a small quantity of non-rubber components, affecting the physical properties of NR, especially the storage hardening via gel formation. The free and/or linked non-rubber components were removed from NR by various treatments. The origin of gel formation in NR mainly resulted from proteins, which could be removed by enzymatic deproteinisation

Investigation of Maillard reaction in natural rubber (NR) latex was carried out using two reducing sugars, glucose and ribose. Both reducing sugars together with a 1:1 mixture were added as 5 wt% solution to concentrated NR latex preserved with ammonia in a 1:1 ratio and preheated at 27, 70 and 90 °C for 2 h. The changes in the latex due to the reaction were characterised using pH and L values for

Natural rubber (NR) is the most preferred raw material for both tyre and non-tyre applications, which require good adhesion performance. It has a naturally sticky character to provide green tack. However, it has limitations to improve adhesion further due to its relatively low reactivity. In this study, epoxidised natural rubber (ENR) has been evaluated as an adhesion promoter for NR based model tyre

In this research, a framework for modelling and simulation of hyper-elastic materials is proposed. The framework explains how to employ strain energy functions as a constitutive model, standard loading test data, and a powerful optimisation method to determine a mathematical function for explaining the mechanical behaviour of a hyper-elastic material using minimum types of loading test data. In the

The effects of a cerium oxide (CeO2) filler on the fatigue properties of heat-aged vulcanised natural rubber (NR) were tested and analysed. The vulcanised NR specimens, filled and unfilled with CeO2, were heat-treated for 24 h. Uniaxial fatigue tests were performed on the two specimens under different strain amplitudes, and the microstructures of the fracture surfaces of the specimens were analysed

To obtain an efficient performance of the natural rubber/graphene oxide nanocomposites, it is essential to enhance the interfacial interaction between the filler and the polymeric matrix. The present study aims to improve the interfacial interaction between natural rubber (NR) and graphene oxide (GO) by modifying GO with zinc oxide nanoparticles (ZGO) using the coprecipitation method. The structural

Partial degradation of high ammonia natural rubber (HANR) in the latex stage was successfully carried out in the presence of periodic acid as a water-soluble degrading agent at ambient temperatures, i.e. 30 °C. The number average molecular weight (Mn), weight average of molecular weight (Mw), gel content and Mooney viscosity were decreased as the periodic acid concentrations increased. The polydispersity

Biocomposites comprising acidified chitosan (CTS) encapsulated in partially cross-linked natural rubber (NR) matrices (CTS-e-NR) were prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FE-SEM). The results of FT-IR, TGA and FE-SEM revealed that CTS was merely encapsulated within partially cross-linked

Dialysed latex C-serum supernatant (DCS) sub-fraction from the rubber tree (Hevea brasiliensis) was reported to exert significant anti-proliferative effect on specific cancer cell lines, especially in human triple negative breast cancer (MDA-MB-231) and human liver carcinoma (HepG2) cells. In the present study, two human non-cancer origin cell lines, MCF-10A (human breast epithelial cells) and HDFa

The rubber tree (Hevea brasiliensis)–cassava (Manihot esculenta) intercropping system is one of the most popular intercropping patterns for small-holder rubber planters. However, this practice is not recommended in some rubber-producing countries, since it is believed that the rubber tree and cassava share some identical pathogens and that the intercropping system will deplete soil fertility. The effects

Used rubber powder was reinforced by corn stalk cellulose to prepare corn stalk cellulose/used rubber powder composites, and the coupling agents 3-mercaptopropyl trimethoxysilane (KH590), r-aminopropyltriethoxysilane (KH550), isopropyl dioleic (dioctylphosphate) titanate (HY101) and bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si69) were used to modify the interphase between used rubber powder and corn

Rigidoporus microporus is a causal agent of white root rot disease of rubber trees. Chemical control is commonly used against this disease but it is expensive, causes environmental pollution and fungal resistance. Silicon is a beneficial element which enhances plant growth and disease resistance but mostly present in insoluble forms. Silicate solubilizing bacteria (SSB) can solubilize the insoluble

Calcium carbonate (CaCO3) is an important filler, widely used rubber industries, particularly in natural rubber latex dipped such as gloves. The main advantages are cost reduction and product improvement. With the development of technology in superfine filler production, the use of CaCO3 as a non-reinforcing filler has gained much attention as it could help to improve natural rubber (NR) product properties

The objective of this paper is to present the study of density parameter in a disk made of orthotropic material and rubber by using Seth’s transition theory. This theory includes classical macroscopic solving problems in plasticity, creep relaxation, and semi-empirical yield conditions. It has been observed that disk made of rubber material requires higher angular speed to yield at the internal surface

The use of recycled crumb rubber (CR) in asphalt pavements could be an essential step towards ensuring a more sustainable future in addition to opening a new investment opportunity for global investors. Asphalt modifiers have the ability to enhance the performance of flexible pavements and contribute towards ensuring a more sustainable environment. The utilization of CR produced from end-of-life tires

The functionalized multi-walled carbon nanotubes (F-MWCNTs) filled polyethylene oxide (PEO) nanocomposites were prepared by casting technique and characterized by scanning electron microscopy (SEM), polarized optical microscopy (POM), thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The MWCNTs were functionalized by Friedel–Crafts acylation, which introduced aromatic amine

A total of 76 Corynespora cassiicola isolates collected from 16 rubber clones in several geographic regions of Vietnam, were studied for genetic diversity by ribosomal DNA internal transcribed spacer (rDNA-ITS) sequences and sequence-related amplified polymorphism (SRAP) techniques. Results of rDNA-ITS sequence analysis indicated 2 nucleotide polymorphisms at the 135th (cytosine/thymine) and 474th

Chopped basalt fibre (BF)-reinforced silicone rubber/fluorine rubber composites were investigated to improve their mechanical and thermal properties, in which the blend of silicone rubber (MVQ) and fluorine rubber (FKM) was used as a matrix of the composites, the BF was used as a reinforcement, and the coupling agents of KH550 (3-amino propyltriethoxysilane), KH590 (3-mercaptopropyl trimethoxysilane)

The laminated natural rubber bearings (NRBs) used in offshore or sea-crossing bridges, are subjected to marine environments over an extended period and therefore vulnerable to the effect of alternating ageing and sea corrosion caused by weather conditions such as temperature, rain, sun, sea winds, waves etc. In addition, there are no systematic theories about the tension capability for NRBs now. Therefore

Corynespora cassiicola is a cosmopolitan fungus with a broad host range. One of the hosts often severely impacted is the rubber tree, Hevea brasiliensis on which it causes devastating leaf defoliation. To date, control of the disease is mainly focused on the application of fungicides, but this only provides short-term solution. Functional genomics through transformation allows evaluation of the disease

Field latex is an important raw material in Thailand, produced by a large number of smallholders and handled by numerous local traders. This diversity of stakeholders involved along the production and marketing chain could result in the variability of the latex quality delivered to the factories. Latex processing industries need a raw material with consistently specified properties. Therefore, it is

Certain materials such as wax, when incorporated into rubber formulations, bloom and form a surface barrier layer against ozone attack. The ozone resisting film results in an unpleasant appearance on the rubber surface. In tyres, sidewalls are more susceptible to ozone attack leading to degradation both in dynamic and static conditions. Also, tyre appearance is an important factor in quality control

Isolators have become more attractive to researchers and industries alike over the past decade. Nonlinear stiffness for the rubber isolator is designed in the floating slab system to obtain or maintain the desired natural frequency. According to the vibration mechanics theory, the natural frequency formula can be deduced backward to obtain the function of stiffness. This then yields a simple integral

The present paper presents numerical and experimental comparative studies between the conventional bending process (bending using punch and V-die) and bending with a rubber-pad cushion. In fact, a finite-element method is introduced to compare these two procedures used to bend AA1050-H14 Aluminum thin sheet. An elastoplastic constitutive model with quadratic yield criterion of Hill 48 and isotropic

Carbon black is the prime component used in tyre manufacturing. Normally, 40–60 phr of carbon black is added in rubbers to enhance their physico-mechanical properties. Utilisation of high amounts of carbon black during tyre manufacturing will certainly lead to more fly loss, which may create several health hazards to humans involved in the mixing operation. This research work aims to partially replace

The purpose of this paper is to present a study of elastoplastic deformation in an isotropic material disk with shaft subjected to variable density and load using Seth’s transition theory. This theory includes classical macroscopic solving problems in plasticity, creep and relaxation and assumes semi-empirical yield conditions. It has been observed that the values of angular speed decreased with increases

TiO2/sericite (Ser) was prepared by depositing a nano-TiO2 film onto a carrier composed of sericite, an inorganic and nonmetallic mineral. Ultraviolet-resistant and antibacterial layers were then separately loaded onto the nano-TiO2 film, forming a multifunctional composite. The obtained functional TiO2/Ser composite was used as a filler and introduced into a rubber composite. It was indicated that

AbstractIn this work, a noble method is used to develop clay–polymer nanocomposite (CPN) with improved dispersion of bentonite clay (as reinforcing filler) in a nano-Styrene Butadiene Rubber/Natural Rubber blend system. The tendency of the clay particles to agglomerate has been reduced to a great extent. The observed increase in tensile modulus and the storage modulus of the ultimate CPN is attributed

Waste rubber with three-dimensional structure is insoluble and non-melting, which creates recycling problem. The technique called “high-pressure high-temperature sintering” (HPHTS) can convert vulcanized rubber powder into usable rubber products. However, reversion occurs when vulcanizates are exposed to a prolonged treatment at high temperature. This reversion results in the decrease of mechanical

The rubber tree (Hevea brasiliensis) is the world’s major source of natural rubber. An expedition to the Amazonas and Para states by the Rubber Research Institute of Malaysia (RRIM) in 1995 led to the successful collection of more than 50,000 genotypes from different locations of the states to broaden the existing gene pool. Realising the severe limitations faced with large germplasm, a core collection

The incorporation of prevalent industrial wastes (i.e. residues) from sugar industries as reinforcing fillers in rubber composites has emerged as a viable solution, enabling improvements in the environment, and getting rid of bagasse waste has also resulted in cost reduction of the final rubber products. In this study, the use of maleic anhydride was proposed to improve the interfacial adhesion between

This article investigates the effect of swelling temperature on palmitic acid-based shape memory natural rubber (SMNR). SMNR has high storage modulus and excellent energy absorption capability which is suitable to replace the electronic parts in the lightweight machine. Although the swelling process increased the trigger temperature of palmitic acid-based SMNR, high thermal energy in swelling process

Many researchers believe that the adhesion failure between rubber and cement paste is one of the main reasons the strength of concrete containing these aggregates drops sharply. This paper provides strength and durability experiment results which reveal the effect of pre-coating rubber granules with crushed dune sand in terms of their mechanical performance, these tests aimed to enhance the durability

High cis-polybutadiene (HCBR) was epoxidized by using in situ formed formic acid and hydrogen peroxide in the absence and presence of Tween 20 at 50 °C at different reaction times. Epoxidized HCBR (EHCBR) with degree of epoxidation from 3.7 to 38.8% was obtained. Low degree epoxidation EHCBR are semi-crystalline rubbers presenting lower crystallization temperatures than the non-epoxidized rubber on

Full-length cDNA libraries (< 1 kb, 1–2 kb, 2–3 kb, 3–6 kb size ranges) were generated from latex of a Hevea brasiliensis tree clone, RRIM 600, for PacBio Iso-Seq sequencing. The total number of high-quality consensus sequences obtained from nearly 20 Gb of raw reads was 207,943 having an average length of 1823 bp and N50 of 2538 bp. Mapping of high-quality consensus sequences to the published Reyan

To date, epoxidized natural rubber (ENR) latex is still far from being commercially available for the production of dipped latex goods although the process was reported in 1922. Therefore, the objective of this work is to establish an understanding on the colloidal properties of ENR latex and relate them to coagulation and film formation. To do so, ENR latex was first prepared from low ammonia preserved

In this study, response surface methodology and desirability function approach (DFA) were used to optimise the vulcanisation process of elastomeric bearings to obtain better quality products. For this purpose, compressive stiffness and vertical deflection under maximum load were determined as response variables with a target at 198 kN/mm and 3.46 mm, respectively, in accordance with customer’s request

In this work, a novel self-healing natural rubber was developed, and the concepts of mixing both covalent and reversible ionic crosslinks bonds were proposed. The developed materials have the capability of repairing themselves and recovering functionality when they are damaged without the need for detection. Evidence that covalent and reversible ionic crosslinks bonds had occurred was determined by

The original version unfortunately contained mistakes. The institution of the author Jitladda Sakdapipanich was wrong.

Our aim was to study the association between the rubber accelerators and predisposing factors of irritant contact dermatitis (ICD) among the semiconductor factory workers. The research design was a historical cohort study. The study population was divided into two groups: (1) the rubber accelerator exposure group, including workers who wore natural rubber finger cots containing 2,2 dibenzthiazyl disulfide

During the last 21 year period from 1996–2016, the total value of imports of rubber and rubber products grew at a rate of 17.66% compared to 14.18% growth rate in the value of exports. As a result of higher growth in imports and lower growth in exports, in the last 10 years, external trade in this segment had shown negative balance of trade consistently. In 2016–2017, the country had a negative balance

Wear and high–low temperature resistance composites with enhanced mechanical and thermal properties were preparation by carbon fiber (CF) reinforced silicone rubber (MVQ)/fluorine rubber (FKM), the coupling agent was used as a compatibilizer. The effect of coupling agent type and content on mechanical properties of CF/MVQ/FKM composites was investigated, the interaction between coupling agent and composites

Vulcanisation is the key process for determining the final properties of elastomers due to the relationship between curing condition and viscoelastic behaviour. This study focuses on the variations in the dynamic behaviour of silica-filled natural rubber caused by crosslinking. The rubber samples with different degrees of curing (DOC) are prepared by thermal quenching during the crosslinking process

In this work, plasma and surface coating technologies were combined and used in the modification of room-temperature-vulcanisated silicone rubber (RTV), and their properties were characterised and compared. First, the surface of pure RTV was cured by different plasmas to improve its roughness and hydrophilicity. The plasmas used was nitrogen, oxygen, and atmosphere plasmas. Then, a type of silicone

This paper describes the utilisation of urea as a single chemical agent to obtain deproteinised high ammoniated natural rubber latex (HA-NRL). The role of urea in HA-NRL deproteinisation was further investigated by employing two different concentrations of urea solution which are low (0.01–0.05%) and high (1.0–5.0%) concentrations. The study assessed the potential usage of urea as a single denaturing

The current practice of concentrated natural rubber latex production includes the reduction of magnesium ion (Mg2+) with the addition of diammonium phosphate (DAP) before being transferred to undergo concentration by a centrifugation process. But in this process, the chemical reaction between Mg2+ and DAP produces a sludge waste. In this research, cationic exchange resins are used to prevent the formation

The use of base isolation to protect a structure and its contents from earthquake damage has proven to be an effective anti-seismic strategy during past earthquakes. Modelling of the isolation system is one of the key steps in understanding the response of the structure and more importantly to evaluate the effectiveness of the isolation system. This paper presents a study on the effect of damping in

Various types of chemical ingredients are needed in the rubber compounding process to obtain desired properties for a commercially useful application. To content with this, Plackett–Burman design (PBD) provides an efficient way of dealing with a large number of variables and identifying the most important parameter. This study reviews the exploitation of PBD to screen the significant effect of different

To evaluate the ablation/erosion resistance of the silicone rubber composites, a new method based on multi-phase flow produced by oxygen–kerosene ablation test device was put forward and a new kind of particle was applied in the test. The phase transition characteristics of B2O3 particles and Al2O3 particles in high-temperature flame jet were investigated and compared. On this basis, the ablation tests

In this work, the interaction between PCC in NR latex and physical properties of the resulting films were studied. PCC dispersion was first prepared and its colloidal properties together with the colloidal properties of prevulcanised natural rubber (PV-NR) latex were investigated using particle size analysis, zeta potential and rheology. PCC dispersion and PV-NR latex were then mixed together and their

In recent years, various types of elastomeric isolators are used for seismic isolated buildings globally. International standards for elastomeric seismic-protection isolators, ISO 22762 were first developed in 2005, and this standard has been revised through a systematic review to issue the 3rd edition now (3rd edition was issued in October 2018). This paper describes breaking test results of elastomeric

The microdispersion of silica in filled elastomer vulcanisates was evaluated by transmission electron microscopy (TEM)—network visualisation analysis. In this study, the silica is modified with a wide range of coupling and non-coupling silanes. The silica-filled elastomer samples were microtomed using a glass knife. The resulting TEM micrographs were interpreted and characterised based on aggregates

High ammonia (HA) natural rubber latex (NRL) is generally very sensitive at lower temperature and will form big rubber lumps after the freezing and thawing processes. The growth of ice crystals in an aqueous medium during freezing causes the rubber particles to move closer together and thus disrupts the protein cloud surrounding the latex particles. The broken protein cloud causes rubber particles

Flex life of three different grades of polybutadiene rubber (BR) with highly linear chains, linear chains and long-branched chains was measured. The rubbers were reinforced with a precipitated silica nanofiller, the surface of which had been pre-treated with sulphur-bearing bis(3-triethoxysilylpropyl-)-tetrasulphane (TESPT) coupling agent. The rubbers were cured by reacting the sulphur in TESPT with

The original form of Natural Rubber (NR) has limited usage despite its excellent elasticity and reversible deformability. Further improvement of its undesired properties, i.e. low hardness, durability and tear resistance will allow for application of NR on a broader scale. Traditional reinforcing materials such as carbon black have indicated improvement in NR-based composites. However, the increasing

The use of kenaf has been extensively explored since its introduction in 1999 by the Malaysian government. However, its lacking application in rubber latex motivates the present study on preparation of kenaf bast fibre dispersions for the latex based industry. The fibres were first dry ground using four stainless steel sieve rings with different trapezoidal perforated diameters. This was followed by

The synthesis of polyisoprene (isoprene rubber) in latex form was carried out by conventional emulsion polymerisation and by miniemulsion polymerisation using hexadecanol as a hydrophobe and the two methods compared. The influence of an emulsion system, monomer and surfactant concentration on conversion, particle size, gel content and coagulation were investigated. Molecular characteristics, thermal

In this study, deproteinised natural rubber (DPNR) latex has been used to fabricate three prototypes of DPNR slow-recovery latex foam, which are latex foam mattress, shoe insoles and wheelchair cushion. The uniqueness of the DPNR slow-recovery latex foam is its ability to conform to the body shape according to both body weight and pressure, and thereafter to recover slowly from the impression made

Ethylene propylene diene polymethylene (EPDM) rubber is one of the fastest growing synthetic rubbers in the market. It is widely used in many fields due to its easy processing and high resistance against outdoor conditions compared to other rubber types. However, like all organic compounds, over time it is degraded under weathering conditions such as radiation, heat, ozone and chemical media, all of