Mechanical Properties Of Natural Rubber Research Articles

Combustion and mechanical properties of natural rubber based on carboxyl modified carbon nanotubes and intumescent flame retardant

ABSTRACT The flame retardant natural rubber (NR) composites were prepared using carboxyl modified multi-walled carbon nanotubes (CMCNTs) and traditional intumescent flame retardant with the ratio among ammonium polyphosphate (APP), melamine (MEL), and pentaerythritol (PER) of 3/1/1. The flame retardancy and thermal stability, and mechanical properties of NR composites were investigated by the LOI test, UL-94 test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), and tensile test, respectively. The results showed that NR/IFR3/2.0CMCNT had good flame retardancy and past the UL-94 test V-2 rating. The peak of heat release rate (pHRR), the peak of smoke production rate (pSPR), and the total smoke production (TSP) of NR/IFR3/2.0CMCNT were lower than those of NR/IFR3, which were reduced by 4.4%, 12.1%, and 26.3%, respectively. In addition, CMCNTs can improve the elongation at the break of NR composites with the increase of CMCNTs under the condition of low load CMCNTs.

Study of Aquilaria crassna Wood as an Antifungal Additive to Improve the Properties of Natural Rubber as Air-Dried Sheets.

Fungal growth on rubber sheets confers inferior properties and an unpleasant odor to raw natural rubber (NR) and products made from it, and it causes environmental concerns. The purpose of the present work was to investigate the effects of Aquilaria crassna wood (ACW) on the antifungal, physical and mechanical properties of NR as air-dried sheets (ADS) and ADS filled with ACW. The results show that the ACW-filled ADS had an increased Mooney viscosity, initial plasticity (PO), and high thermo-oxidation plasticity (i.e., high plasticity retention index PRI). Additionally, superior green strength was observed for the ACW-filled ADS over the ADS without additive because of chemical interactions between lignin and proteins in NR molecules eliciting greater gel formation. A significant inhibition of fungal growth on the NR products during storage over a long period (5 months) was observed for ACW-filled ADS. Thus, it can be concluded that ACW could be applied as an antifungal additive that reduces fungal growth. This is a practically important aspect for the rubber industry, as fungal growth tends to spoil and cause the loss of NR sheets during storage. Moreover, the ACW is active as an incense agent, reducing negative impacts from odors that fungi, on rubber surfaces, release. Therefore, these filled intermediate NR products provide added value through, an environmentally friendly approach, this is pleasant to customers.

Nanocomposite of Fullerenes and Natural Rubbers: MARTINI Force Field Molecular Dynamics Simulations.

The mechanical properties of natural rubber (NR) composites depend on many factors, including the filler loading, filler size, filler dispersion, and filler-rubber interfacial interactions. Thus, NR composites with nano-sized fillers have attracted a great deal of attention for improving properties such as stiffness, chemical resistance, and high wear resistance. Here, a coarse-grained (CG) model based on the MARTINI force field version 2.1 has been developed and deployed for simulations of cis-1,4-polyisoprene (cis-PI). The model shows qualitative and quantitative agreement with the experiments and atomistic simulations. Interestingly, only a 0.5% difference with respect to the experimental result of the glass transition temperature (Tg) of the cis-PI in the melts was observed. In addition, the mechanical and thermodynamical properties of the cis-PI-fullerene(C60) composites were investigated. Coarse-grained molecular dynamics (MD) simulations of cis-PI-C60 composites with varying fullerene concentrations (0–32 parts per hundred of rubber; phr) were performed over 200 microseconds. The structural, mechanical, and thermal properties of the composites were determined. The density, bulk modulus, thermal expansion, heat capacity, and Tg of the NR composites were found to increase with increasing C60 concentration. The presence of C60 resulted in a slight increasing of the end-to-end distance and radius of the gyration of the cis-PI chains. The contribution of C60 and cis-PI interfacial interactions led to an enhancement of the bulk moduli of the composites. This model should be helpful in the investigations and design of effective fillers of NR-C60 composites for improving their properties.

Preparation and characterization of Kaolinite supported lanthanum-hydroxide and its improvements for natural rubber composites

Kaolinite supported lanthanum-hydroxide was successfully prepared via a deposition method and used to improve the mechanical properties of natural rubber (NR) composite. A series of techniques including X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the samples. The XRD, FT-IR, and EDS results show that lanthanum-hydroxide was successfully loaded on the surface of Kao and may interact with the inner surface hydroxyls. The surface and edge of Kaolinite gradually become rougher, and the lamellar structure had defects due to the loading of lanthanum hydroxide. The resulting material had a uniform dispersion in the natural rubber composite. The scorch time (t10) and curing time (t90) of the filled NR composites decreased simultaneously relative to pure NR, and decreased when compared to that of raw Kao. The tear strength reached at 57.35 kN/m, which increased by 54% relative to that of pure NR. The thermal stability of the prepared composites improved with loading of lanthanum-hydroxide. The reinforcement of the mechanical properties of the filled NR composite is attributed to the fine dispersion of lamellar-like particles in a rubber matrix with restrictions on rubber chain motion via trapping rubber chains and improvements in the incorporation between rubber molecules and filler particles due to the complexation between the rare earth element on the surface of Kao and the double-bond in rubber chains.

Effect of flame retardant on the physical and mechanical properties of natural rubber and sugarcane bagasse composites

Effect of flame retardant on the physical and mechanical properties of natural rubber and sugarcane bagasse composites

Enhanced Mechanical Properties of Natural Rubber by Block Copolymer-Based Porous Carbon Fibers

Enhanced Mechanical Properties of Natural Rubber by Block Copolymer-Based Porous Carbon Fibers

Morphological, thermal, and mechanical properties of natural rubber reinforced with cellulose nanofibers from oil palm empty fruit bunch

Morphological, thermal, and mechanical properties of natural rubber reinforced with cellulose nanofibers from oil palm empty fruit bunch

Influences of porous reduction graphene oxide/molybdenum disulfide as filler on dielectric properties, thermal stability, and mechanical properties of natural rubber

AbstractA ternary composite system consisting of natural rubber (NR), porous reduced graphene oxide (rPGO), and molybdenum disulfide (MoS2) was introduced for applying in the dielectric field, of which rPGO and MoS2 hybrid conductive filler (rPGM) was prepared by an effective and environmentally friendly method‐microwave reduction. And the well‐dispersed NR composites (NGM) were made by the latex co‐precipitation method. Due to the large specific surface area of rPGM itself and the synergistic dispersion of rPGO and MoS2, it formed many stable interface structures with the NR matrix, which not only made the blend exhibit high elasticity and withstood large deformation as NR but also greatly improved the dielectric, mechanical and thermal stability of the NR matrix. Compared with neat NR, the dielectric constant of nanocomposite increased by 11 times in the presence of rPGM conductive filler, and the leakage current generated by direct contact of fillers was reduced due to the attachment of MoS2 to the surface of rPGO; when 2% rPGM was added, the NR exhibited the highest tensile strength (21.3 MPa), elongation at break (495%), and abrasion resistance (0.165 cm−3); in addition, the thermal stability of the nanocomposite was also improved. These phenomena indicate that rPGM had great potential in conductive fillers and provided a reliable way for NR applications in the field of dielectric elastomers.

Effect of 〖TiO〗_2 on the mechanical properties of natural rubber (SMR 30) and X-Ray penetration resistance.

The natural rubber (SMR 30) was reinforced with micro particle powder TiO_2 with different ratio of (20 – 100) pphr also study the effect of TiO_2 on mechanical properties in different ratio. The tensile, modulus and hardness was increasing while elongation was decreasing. X-Ray penetration resistance for the sample of rubber composite with TiO_2 at (100) pphr was week at 20 KV so the TiO_2 was giving the composite rubber white color.

The effect of carbon black on the curing and mechanical properties of natural rubber/ acrylonitrile- butadiene rubber composites

The present work investigates the effect of the amount of carbon black on curing and mechanical properties such as tensile strength, elongation at break, hardness and abrasion resistance of the natural rubber (NR)/ acrylonitrile-butadiene rubber (NBR) blend. For that purpose, a blend composed of 65% NR and 35% NBR filled with different content of carbon black N330 was used. The curing results indicate that the viscosity and the crosslink density of rubber composites increase and the scorch and curing times decrease with increasing the filler content. Mechanical properties such as tensile modulus and hardness of the CB filled NR/NBR blend were remarkably improved, indicating the inherent reinforcing potential of CB. Regarding tensile strength and abrasion resistance, they increase with the addition of carbon black, up to 50 phr. After that, these properties decrease slightly with filleraddition.

Comparative analysis of latex transcriptomes reveals the potential\xa0mechanisms\xa0underlying\xa0rubber molecular weight variations\xa0between the Hevea brasiliensis clones RRIM600 and Reyan7-33\u201397

BackgroundThe processabilities and mechanical properties of natural rubber depend greatly on its molecular weight (MW) and molecular weight distribution (MWD). However, the mechanisms underlying the regulation of molecular weight during rubber biosynthesis remain unclear.ResultsIn the present study, we determined the MW and particle size of latex from 1-year-old virgin trees and 30-year-old regularly tapped trees of the Hevea clones Reyan7-33–97 and RRIM600. The results showed that both the MW and the particle size of latex varied between these two clones and increased with tree age. Latex from RRIM600 trees had a smaller average particle size than that from Reyan7-33–97 trees of the same age. In 1-year-old trees, the Reyan7-33–97 latex displayed a slightly higher MW than that of RRIM600, whereas in 30-year-old trees, the RRIM600 latex had a significantly higher MW than the Reyan7-33–97 latex. Comparative analysis of the transcriptome profiles indicated that the average rubber particle size is negatively correlated with the expression levels of rubber particle associated proteins, and that the high-MW traits of latex are closely correlated with the enhanced expression of isopentenyl pyrophosphate (IPP) monomer-generating pathway genes and downstream allylic diphosphate (APP) initiator-consuming non-rubber pathways. By bioinformatics analysis, we further identified a group of transcription factors that potentially regulate the biosynthesis of IPP.ConclusionsAltogether, our results revealed the potential regulatory mechanisms involving gene expression variations in IPP-generating pathways and the non-rubber isoprenoid pathways, which affect the ratios and contents of IPP and APP initiators, resulting in significant rubber MW variations among same-aged trees of the Hevea clones Reyan7-33–97 and RRIM600. Our findings provide a better understanding of rubber biosynthesis and lay the foundation for genetic improvement of rubber quality in H. brasiliensis.

Production of Bacterial Cellulose from Food Industrial Waste and its Application on Natural Rubber

Bacterial cellulose (BC) is high purity and several current potential uses in industries. Liquid byproduct of sweet corn canning process (SC) contains fermentable sugars which could be utilized to get higher economic benefits. Therefore, this research aimed to produce BC from SC by Gluconacetobacter xylinus under static condition and use it to improve mechanical properties of natural rubber. The ratio of SC to coconut juice for cellulose production was studied. The result revealed that production yield, water holding capacity and tensile strength of BC produced from the medium containing coconut juice to SC at a ratio of 75:25 (w/w) supplemented with 1% acetic acid, 1% ammonium sulfate and 5% sucrose (w/w) was not significant different from BC obtained from a coconut juice medium. The FTIR spectra of BC showed the characteristics of cellulose. The morphology of BC exhibited high fibril network. BC is showed reinforcement in natural rubber composites due to enhance the stress value, whereas reduce the strain value.

Optimization of mechanical properties of CNT-rubber nanocomposites

Rubber nanocomposites were prepared by adding required amount of Multiwall carbon nanotubes (MWCNT) in varying proportions (0.5, 1, 1.5, 2 and 2.5 wt%) as nano reinforcement and carbon black in varying proportion (0, 10, 20, 30 and 40 phr) as filler. The chemicals were added in the following order (Natural Rubber, Antioxidant: 1 phr, Oil: 5 phr, Zinc Oxide: 4 phr, Stearic Acid: 2 phr, Accelerator: 1 phr, Sulfur: 2phr) in double roll mill to process rubber nanocomposites. The result revealed that the incorporation of Multiwall carbon nanotube (MWCNT) has significantly improved the mechanical properties of natural rubber. In this work an attempt has been used to find rubber nanocomposite system which posses best combined mechanical by TOPSIS Method.

Morphological and Mechanical Properties of Natural Rubber Compound/Poly(butylene succinate) Blend

Biodegradable poly(butylene succinate) (PBS)/natural rubber compound (NRC) blend was melt mixed using a two-roll mill. A weight ratio of PBS/NRC was 100/0, 90/10, 80/20, 70/30, 60/40 and 50/50. Morphological and mechanical properties were investigated. The results showed that the elongation at break increased with an increase of NRC content until the ratio of 80/20. While the tensile strength continuously decreased with an increasing amount of NRC. Moreover, the impact strength of the PBS/NRC blend increased until the ratio of 80/20 and tended to decrease in the further ratios. Morphology of PBS/NRC blend showed that NRC had good dispersion in PBS matrix up to 80/20. When the amount of NRC was increased, it became a larger particle due to an agglomeration, resulting in the mechanical properties.

Physical and mechanical properties of natural rubber modified cement paste

Cemented materials have high compressive strength but low toughness and flexural strength. This research evaluated improvement of toughness and flexural strength of cemented materials with the addition of natural rubber (NR), based on the results from extensive testing of the cemented pastes. While mixing with cement (C), Sodium dodecyl sulfate (SDS) was used as a surfactant admixture to provide stability to the NR particles. The natural rubber modified cement (NRMC) pastes were prepared by varying the influence factors, namely: SDS/C ratio, SDS to dry rubber content (SDS/DRC) ratio, and DRC/C ratio at the same water to cement (W/C) ratio of 0.55. The DRC/C ratios were varied in the range of 0–50%. The role of the influence factors on bulk density, setting time, temperature of setting paste, compressive and flexural strengths, and toughness of NRCM pastes were also studied in this research. Scanning electron microscopy (SEM) images and energy dispersive spectrometry (EDS) were carried out on the NRCM pastes to confirm on the presence of NR films and air bubble in the NRMC pastes. The bulk density was found to decrease in proportion to the increases in the SDS/C and DRC/C ratios. The addition of NR latex was found to improve the flexural strength and toughness, whilst retarding the setting time and hydration. The flexural strength was found to be increased with increasing DRC/C, up to the optimal value. Beyond this optimal value, the flexural strength decreased but with higher flexural deflection. The optimum SDS/DRC ratio of 10% and DRC/C ratio of 10 provided the highest compressive and flexural strengths of NMPC paste. The knowledge gained from this study provides useful information for further research and practice in infrastructure engineering applications such as earthquake-resistant lightweight cement wall and impact-resistance products.

Study on Mechanical Properties of Natural Rubber by Carbon Black/Graphene/White Carbon Black

Graphene (GE) and white carbon black (SiO2) were added to natural rubber (NR) to partially replace carbon black (CB). The effects of different filling ratios of CB/GE/SiO2 on the mechanical properties of NR were investigated. The data were processed by orthogonal experiment. The results showed that when the mass fraction of CB was 41g, the mass fraction of GE was 4g, and the mass fraction of SiO2 was 1g, the maximum true strain in the mechanical properties of NR was 139.8%. The maximum true stress is 85.695 MPa, and it is indicated that41g CB, 4 g GE, and 1 g SiO2 are added to the NR as the optimum filling ratio.

Rubberwood sawdust filled natural rubber composites: effects of filler loading and zinc oxide content

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) and zinc oxide contents on mechanical properties of natural rubber (NR)/RWS composites. The curing characteristics of the composites were determined and the composites were vulcanized at 150°C for 10 min and a pressure of 1000 psi using a hot press machine. The properties of the composites such as tension, hardness and morphology were characterized. The increasing additions of RWS in range of 20-100 phr increased the minimum torque (ML), maximum torque (MH) and hardness of NR/RWS composites, but tensile strength and elongation at break of the composites decreased. Further, an increment of zinc oxide contents in range of 3-5 phr into the composites slightly affected the ML, MH, hardness and tensile properties. Therefore, the addition of zinc oxide 3 phr is recommended to achieve the properties of NR/RWS composites as well as saving cost.

The effects of nano-sized montmorillonite on rheological and mechanical properties of natural rubber

A semi EV curing system was applied for studying the effects of nano-sized montmorillonite on rheological and mechanical properties of natural rubber (NR) composites. The montmorillonite as a nano-sized filler which was added into NR at 2.0, 4.0, 6.0, 8.0 and 10.0 parts per hundred rubber (phr). It was found that the montmorillonite functioned as a co-curing agent and reinforcing filler. It decreased the scorch and cure times of the NR composites. The higher the montmorillonite loading, the shorter the scorch and cure times were. It also increased the torque difference, tensile modulus and hardness but decreased the elongation at break. The tensile strength was improved up to an 8.0 phr. of montmorillonite loading.

Study to enhance the mechanical properties of natural rubber by using the carbon black (N550)

Natural rubber is one of the important material in the manufacturing industry with applications varying from footwear to an aircraft industries. An investigation was conducted on the nature of material so as to increase its effectiveness in its function in cleaning off water, dust and other impediments of the windscreen of automobiles. A research has been conducted on various compositions of rubber by adding various fillers to improve the properties. The main objective of this work is to enhance the mechanical properties of the natural rubber used in the windshield wiper blade using Carbon black (N550) in two different compositions. Abrasion test, hardness test, tensile and tear tests were conducted on the specimen.

Styrenated phenol modified nanosilica for improved thermo-oxidative and mechanical properties of natural rubber

The present work aims to prepare thermal and oxidation resistant Natural Rubber (NR) composites using antioxidant-modified nanosilica (MNS). The thermo-oxidative aging performance of the composites was evaluated by the variations in mechanical properties after aging at 100 °C for 24 h. The performance was further monitored through Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy, Thermogravimetric Analysis, and Dynamic Mechanical Analysis. NR nanocomposite with 1–7.5 phr nanosilica (NS) and 3 phr MNS were prepared and its rheological properties were studied. A comparative study of the theoretical models yielded that modified Guth-Gold equation predicted Young's modulus better than other models. Thermal stability of natural rubber MNS composite was improved by 10 °C with pre-eminent mechanical properties like tensile strength and heat build-up. A linear relationship of compression set with modulus of all composites were also established. Equilibrium swelling test revealed improved crosslink density in NR MNS composite. The strong interaction between antioxidant and nanosilica enabled low migration of antioxidant in NR MNS composite. Hence its protective function after aging showed more effective than NR NS composites. These versatile functional properties of NR MNS composite suggest its potential application in electrical, electronic and high performance rubber products.