Blends Of NR Research Articles

Optimizing natural rubber blends for examination gloves: Vacuum radiation for mechanical strength and solvent barrier

AbstractNatural rubber (NR) is emblematic of sustainability compared to synthetic rubber. However, the tradition of adding sulfur as a vulcanization ingredient results in the release of toxic substances and the potential for health issues. In this study, a feasible strategy was proposed to replace sulfur and discover a safe bulk modification process for NR films. The results have shown that the NR particle size was disintegrated to below 10 nm by gamma irradiation. High tension strength up to 24.45 MPa was observed in the vulcanized NR blend film, which could be elongated up to 800% strain after exposure to an optimum dose of 14 kGy. In comparison to commercial NR latex and nitrile gloves, the vulcanized NR/ SIS films exhibited better chemical resistance ability against hexane, methanol, toluene, and acetone, as revealed by the permeation test. The appearance of amorphous regions and highly oriented NR crystallites was observed through transmission electron microscopy. Findings from this study propose the vacuum radiation strategy that can replace conventional vulcanization methods, resulting in NR films with high mechanical and barrier performance. Furthermore, the emission of toxic substances is reduced by this green process, making it practically useful for potential chemical‐resistant examination glove applications.

Chemical structure of rubber powder on the compatibility of rubber powder asphalt

The sedimentation problem of waste rubber powder in asphalt not only restricts the engineering application of rubber powder asphalt, but also impedes the recycling of waste rubber. To solve this industry malady, this study designs and prepares three different chemical structures of rubber powder, and systematically investigates the influence of the chemical structure of rubber powder on the compatibility of rubber powder asphalt by cigar tube test, dynamic shear rheology test, microscopic characterization analysis, and molecular dynamics method. The microstructure results indicate that new characteristic peaks (such assulfonic acid groups, thiol groups, and amino groups) appeared in the infrared spectra of each of the modified rubber powder. The elemental analysis further proves that the sulfur and hydrogen contents of the mechanochemical modified rubber powder (AR) have been reduced, the carbon and hydrogen contents of the sulfonated modified rubber powder (SR) have been reduced, and the nitrogen contents of the tetraethylenepentamine with mechanochemical co-modified rubber powder (NR) have been increased. These facts indicate that different chemically structured rubber powder have been successfully prepared. The macroscopic results show that NR and asphalt blends has a lower softening point difference (2.1 ℃) and segregation index (12%), followed by SR and AR, and waste rubber powder (WR) and asphalt blends is the highest in softening point difference (6.3 ℃) and segregation index (35%). Microscopic characterization results show that NR, SR, and AR can form a fuzzy phase interface with asphalt, and further quantitative analysis finds that NR has the highest compatibility index with asphalt (80%), followed by SR and AR, and WR has the lowest compatibility index with asphalt (36%). Molecular dynamics simulation indicates that the solubility parameter of NR and asphalt is the closest and its difference is the smallest (0.4 (J/cm3) 1/2) as well as the strongest intermolecular interactions (-563.93 kJ/mol), followed by SR, AR, and WR. All the above results reveal that the order of compatibility between four types of chemical structure rubber powder and asphalt is NR > SR > AR > WR. Furthermore, based on macroscopic, microscopic, and molecular dynamics simulation, the compatibility mechanism of different chemically structured rubber powder with asphalt could be that the acidic groups in SR and the thiol functional groups in AR can be dissolved with the acidic groups in asphalt based on the principle of similar solubility, which improves the compatibility of the rubber powder with asphalt. The NR contains strong polar alkaline groups, which can be combined with the acidic components of asphalt based on the principle of acid-base neutralization reaction, thereby improving the compatibility of the rubber powder with asphalt. In view of the above, it is not difficult to see that the combination of tetraethylenepentamine and mechanochemically co-modified rubber powder and asphalt has a promising application in the future construction of pavement engineering and recycling of waste tire resource.

Development of NR/SBR Based Rubber Compounds with Low Hysteresis and High Durability for Transmission V-Belts Applications

Power transmission by the belts is defined as, the transmission of power by a moving pulley to one or more driven machines through a flexible non-metallic member. There are different types of V-belts available,and Transmission Belts are one of them. Transmission V-Belt is the first invented non-metallic belts. Nowadays V-belts are used in various conditions, especially high-power transmission. These V-belts are finding their importance in many heavy industries. One of the good features of this type belt is no slippage occurs during the run. NR and SBR have used elastomers and can act as a base rubber material for this purpose. This study includes the compounding improvement for transmission V-Belts with NR and SBR rubber blends. There were so many numbers of failures in different ways during the initial research. Product failure methods and effect analysis (PFMA) have done by testing the belts multiple times and it has found that the major factors for the failure and less durability were excessive heat build-up (HBU) and poor fatigue resistance, poor crack initiation and growth, the resistance of the materials. So, initially reduction of HBU has successfully made in many steps by studying the properties of various compounds with a different type of fillers combinations, rubber combinations, curing systems variations etc. We have also improved the adhesion strength with cord and fabrics. Initially, we have taken one compound showing better properties in all aspects and have taken Belt Trial. And after some more improvement, we have found a compound showing better properties in all the cases than first trial and regular trials.By using that compound, we have developed Belts and showing better durability than earlier experiments and regular production.

Mechanical and Thermal Properties of Natural Rubber/Poly Lactic Acid /dioctadecyldimethylammonium bromide Modified Clay Nanocomposites

This paper tackles a me1t blend of po1y(lactic acid)/ natura1 rubber with dioctadecyldimethylammonium bromide(DODAB) modified clay. The study investigated mechanical, therma1 and morpho1ogical properties of poly(lactic acid)/ natural rubber and nanocomposites. The paper also examined Montmori1lonite clay with alky1 ammonium ion of (DODAB). the studied parameters, PLA/ NR nanocomposites revealed 1arger enhancements in mechanical properties in comparison to PLA/ NR blend because of high polymer blend matrix shear forces exerted on clay aggregated during mixing po1ymer-clay. The original MMT with Na+ action leads to weak improvements in mechanica1 properties in comparison to organoclays. It is noted that the strength of tensile, modulus, and the nanocomposite samples can be improved with 4% of clay loading. The optimum samp1e morphology and chemical structure were tested by X-ray diffraction and FT-IR spectroscopy respectively. This paper denotes that poly(lactic acid)/ natural rubber-toughened nanocomposites with a higher modulus and in this way, thermal stability could be made.

Properties of natural rubber latex-compatibilized natural rubber/recycled chloroprene rubber blends

The effect of natural rubber latex (NRL) on the properties of natural rubber/recycled chloroprene rubber (NR/rCR) blends was investigated. The properties of NR/rCR-NRL blends were compared with those of NR/rCR blends without the NRL. The addition of NRL showed an improvement in tensile strength, elongation at break, fatigue life, and swelling resistance with respect to those rubber blends without NRL. However, the gel content and glass transition of NR/rCR blends were not significantly affected by NRL. The scanning electron microscopic images showed better rCR dispersion in NR/rCR-NRL blends, indicating that the interfacial adhesion between NR and rCR blends was enhanced. A single tan δ is observed from the dynamic mechanical analysis supported that NRL can be used as compatibilizer in the NR-rich blend.

Reologi, sifat aging, termal, dan swelling dari campuran EPDM/NR dengan bahan pengisi carbon black N220

The blends of EPDM and NR are immiscible in nature and incompatible. Introducing maleic anhydride as a compatibilizer into the blends was expected to produce compatible blends with balanced mechanical properties. The purpose of this research was to determine the effect of EPDM/NR ratio on the rheological, aging, thermal and swelling properties of the blends. The variation of EPDM/NR ratio were 100/0, 80/20, 70/30, 60/40, 50/50, and 40/60 phr. The blends were mixed using two roll mill. The results showed that the addition of NR affects the maximum torque, scorch time, and optimum vulcanization time. In the blends, EPDM plays an important role in improving aging, swelling, thermal properties.

Study of Waste Rubber Powder Blend Mechanical Properties of NR

The study of the mixing method, mixing time, waste rubber powder as the amount of waste rubber powder by resorcinol (R) and six methyl four amine (H) effect on the mechanical properties of waste rubber powder /NR blend modified. The results show that, with effect of blending method, mixing time and waste rubber powder content on mechanical properties of blend vulcanizate; through modification, can greatly improve the mechanical properties of waste rubber powder blend vulcanizates, as the modifier of resorcinol and six methyl four amine mass ratio was 1/0.5, glue the material mechanical properties are the best, the tensile strength is 17.03 MPa.

Rubber bound phenolic antioxidant and its application in thermoplastic elastomer

Natural rubber bound phenolic antioxidant, 2,6-di-tert-butyl-4-vinylphenol (2,6-DBVP), was prepared from natural rubber and 2,6-DBVP in both solution and melt state. The 2,6-DBVP had been synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and methyltriphenylphosphonium iodide (MePPh3I) by Wittig reaction (0°C for 2 hrs, N2 atmosphere). The conditions for preparation of natural rubber bound 2,6-DBVP (NR-DBVP) were optimized for both solution state (1 phr BPO and 8 phr 2,6-DBVP at 70°C for 2 hrs) and for melt state (1 phr BPO and 8 phr 2,6-DBVP at 70°C for 10 mins, with rotor speed of 60 rpm). A thermoplastic vulcanizate was obtained using a compatibilizer, polypropylene modified with phenolic resin (PhHRJ-PP), in a closed mixer (180°C for 3 mins, rotor speed 60 rpm). The antioxidant properties of vulcanized NR-DBVP, using phenolic as the vulcanization system, were similar to NR with the conventional antioxidant BHT. In addition, the antioxidant, water leaching property of the thermoplastic vulcanizate of NR-DBVP/PP were good in comparison to a NR blend with BHT; the morphologies of these thermoplastic vulcanizates were similar.

Rapid and nondestructive quantitative analysis of natural rubber blends regardless of geographical origin and harvest time of the natural rubber

ABSTRACTNatural rubber (NR) blends are widely used in many industries because of their excellent integrated properties. However, a simple, easily operational, nondestructive, and accurate method for their quantitative analysis remains as a challenge. This has been always an important issue in the related industries, particularly for their daily quality control tests. One main reason is that NR ingredients vary according to their geographical origin and the harvest time, which renders it hard to set up a versatile analytical protocol for all NRs. Another reason is owing to the defects of the established methods themselves as having been revealed in those relying on TGA, Py‐GC/MS, FTIR, and ATR‐FTIR. In this study, a simple and feasible method based on near infrared spectroscopy combined with chemometric is proposed to solve this problem for the first time. NR/SBR (styrene‐butadiene rubber) rubber blend, the most widely used NR blend, is selected as a typical research subject. Spectral calibration region, factor, and several different pretreatment methods are applied on the spectra data to optimize calibration models. The result shows the optimized calibration model provides a good accuracy (0.135 wt %), intraday precision (0.121 wt %) and interday precision (0.132 wt %) for 3 months. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41423.

Evaluation of Effect of Various Nanofillers on Technological Properties of NBR/NR Blend Vulcanized Using BIAT-CBS System

Owing to processing ease and resistance to oils and chemicals, NBR is widely used in many industries. But since neat NBR has only poor tensile properties, it is better to use suitable blends of NR and NBR after incorporating appropriate nanoingredients before vulcanization. It is well established that nanoparticles can be easily dispersed in a more uniform pattern in polymer matrix, thereby enhancing the technological properties of the elastomer vulcanizate. Since there are no systematic comparative studies on technological properties of NBR/NR blend containing different nanoingredients, efforts have been made in this study to investigate cure and technological properties like tensile properties, tear resistance, compression set, hardness, abrasion loss and swelling value of NBR/NR (80/20) blend vulcanizates containing stearic acid-coated nano-zinc oxide (ZOS), nano-BIAT, nano-silicate-coated CaCO3, PEO-coated calcium silicate, and surface-modified carbon nanotubes (CNT). XRD and electron microscopy have been used for morphological analysis. The nano ingredients were effective in enhancing the technological properties of the vulcanizates. Among the nanofillers, modified CNT was found to impart superior properties to NBR/NR blend due to more intercalation.

Bentonite as a reinforcing and compatibilizing filler for natural rubber and polystyrene blends in latex stage

Bentonite clay was used as a reinforcing and compatibilizing filler for natural rubber/polystyrene (NR/PS) blend via latex blending process. The reinforcing and compatibilizing performance of bentonite clay in the NR/PS blends were evaluated. The improvement of the mechanical properties of NR/PS blends with the weight ratios of 90/10, 80/20, and 70/30 was found with the addition of 3 and 5 parts per hundred rubber (phr) clay. The characterization by using Fourier transform infrared spectroscopy and X-ray diffraction (XRD) gave the evidence that the silicate layer was intercalated by NR and PS molecular chains. The morphology of tensile fracture surface by scanning electron microscope showed the separated phase boundaries of PS and NR blend and gradual disappearance with the bentonite content. This could be implied that the bentonite contributes to the compatibilization between PS and NR. The compatibilization action of the bentonite clay was also reflected by the shift of glass transition temperature (Tg) of NR to higher temperatures than those of the blends. These results suggested that the tensile and tear properties of the blends were controlled by compatibility between NR and PS. The most enhanced properties of blends were found with the addition of 3 phr bentonite clay. POLYM. ENG. SCI., 54:1436–1443, 2014. © 2013 Society of Plastics Engineers

Thermoplastic Natural Rubber Based on Blending of Co-Polyester: Effect of Amount of Epoxide Groups in Epoxidized Natural Rubber on Preperties

TPNRs based on blending of co-polyester (i.e., PBT/PC) and epoxidized natural rubber (ENR) with various epoxide content (i.e., 10, 20, 30, 40 and 50 mol% epoxide) were prepared by dynamic vulcanization. It was found that the co-polyester/ENR blends gave better properties (i.e., mechanical, dynamic mechanical, morphological and oil resistant properties) than that of co-polyester/unmodified NR blend. It was also found that co-polyester/ENR with 50 mol% epoxide exhibited the highest tensile strength, elongation at break, modulus at 100% elongation, hardness, storage modulus, complex viscosity and oil resistant properties but showed the lowest tension set value. This indicates the highest elasticity. Moreover, it was found that size of vulcanized rubber domains dispersed in thermoplastic matrix decreased with increasing the epoxide content in ENR molecules.

Trial Production Study of All-Steel TBR Tire Using Homogeneous Rare Earth IR

Mooney viscosity, cure characteristics, tensile properties, tear strength, rolling resistance property, abrasion resistance ,dynamic cutting property and other properties of the homogeneous rare earth IR/NR blend were investigated, and compare to Russian SKI-3/NR blend, SKI-5/NR blend and NR. The results showed homogeneous rare earth IR/NR blend has similar or even better properties compare to SKI-3/NR blend, SKI-5/NR blend and NR. The tire products made by these rubbers have similar performance. The tires passed the China National Quality Supervision and Inspection Center of rubber tire certification, which met the requirements of all-steel TBR tire. The homogeneous rare earth IR prepared by Petro China Jilin Petrochemical Company could part instead of NR using in all-steel TBR tire.

Silica Transfer in Ternary Rubber Blends: Calculation and Experimental Determination

AbstractA novel model is presented for predicting the phase selective filler localization in an equilibrium state for ternary rubber blends of SBR, NBR, and NR. It is based on surface tension data of the rubber components and the filler. Phase‐selective filler localization in ternary rubber blends is determined experimentally by means of FTIR spectroscopy on the basis of the wetting concept. It is found that by preparation of ternary blends with certain silica loadings, pre‐mixed in each blend phase using the masterbatch technology, silica transfer processes between blend phases take place until the equilibrium filler distribution is reached. The sequence of the silica transfer processes can be explained by taking into consideration the formation of a phase‐in‐phase morphology of the ternary blend.magnified image

Study and Application of Homogeneous Rare Earth IR/NR Blends in Tread Compound of All-Steel TBR Tire

The homogeneous rare earth IR/NR blend applied in tread compound of all-steel TBR tire was investigated,and compare to Russian SKI-3, SKI-5/NR blends and NR.The results showed homogeneous rare earth IR/NR blend had similar vulcanization characteristics, dynamic mechanical properties and heat-aging resistance or even better. It was inspected that the appearance, balance, air bubbles, X-ray and homogeneity inspection test of the tires produced by homogeneous rare earth IR/NR blend by the tire factory,all the indicators were qualified. The tires passed the China National Quality Supervision and Inspection Center of rubber tire certification. The tires met the requirements of all-steel TBR tire.The homogeneous rare earth IR prepared by Petro China Jilin Petrochemical Company could 40 phr instead of NR using in tread compound of all-steel TBR tire,which could extend tire life and reduce tire material costs.

Novel dynamic vulcanization of polyethylene and ozonolysed natural rubber blends: Effect of curing system and blending ratio

AbstractDynamic vulcanization was studied in terms of the change in α‐relaxation temperatures of the LDPE matrix, morphology, and mechanical properties of LDPE/ozonolysed NR blends which were vulcanized at various blend ratios and with different curing systems, i.e., peroxide and sulfur systems. The ozonolysed NR with Mw = 8.30 × 105 g mol−1 and Mn = 2.62 × 105 g mol−1, prepared by the in situ ozonolysis reaction of natural rubber latex, was used in this study. The significant change in the α‐relaxation temperature of LDPE in the LDPE/ozonolysed NR, dynamically vulcanized using the sulfur system, suggested that sulfur vulcanization of the blend gave a higher degree of crosslink density than using peroxide and corresponded with the improved damping property and homogenous phase morphology. However, the peroxide cured blends of LDPE/ozonolyzed NR gave more improvement of tensile strength and elongation at break than the sulfur cured system. Furthermore, the mechanical properties of tensile strength, elongation at break, and damping were improved by increasing the ozonolyzed natural rubber content in both DCP and sulfur cured blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Preparation and self‐assembly of polyaniline nanorods and their application as electroactive actuators

AbstractTo improve the performance of ion‐exchange polymer–metal composite (IPMC) actuators, an electrical pathway material for enhancing the surface adhesion between the membrane and the metal electrodes of the IPMC was studied. As an efficient electrical pathway material, polyaniline nanorods (PANI‐NRs) doped with p‐toluene sulfonic acid (TSA) were synthesized with a template‐free method. The factors affecting polyaniline morphology were studied with various dopant concentrations and oxidant feeding rates. Highly conductive PANI‐NRs were formed when they were synthesized with ammonium persulfate at a 5.0 mL/min oxidant feeding rate and doped with 0.125M TSA. The conductivity of the PANI‐NRs was 1.15 × 10−1 S/cm, and their diameters and lengths were 120–180 nm and 0.6–2 μm, respectively. To apply the membrane as an actuator, perfluorosulfonated ionomer (Nafion)/PANI‐NR blends were prepared by solution blending and casting. The actuating ability of the three‐layered membrane consisting of Nafion/PANI‐NR blends was then examined and compared with that of Nafion only. The actuating ability of the IPMC was improved when Nafion/PANI‐NRs were used as electrical pathways. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Thermoplastic natural rubber based on oil extended NR and HDPE blends: Blend compatibilizer, phase inversion composition and mechanical properties

The oil extended natural rubber (OENR) and HDPE blends with different rubber–plastic components (i.e., OENR/HDPE=0/100, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, 80/20 and 100/0) were prepared by a melt mixing process at 160 °C. Effect of blend compatibilizer (i.e., phenolic modified polyethylene, PhHRJ-PE) and proportions of OENR/HDPE in the blend on rheological, tensile, morphological and hardness properties were investigated. It was found that the blend with compatibilizer exhibited higher flow and viscosity curves as well as mechanical properties in terms of 100% modulus, tensile strength and elongation at break. SEM micrographs and rheological properties indicated that the blends of OENR/HDPE are two-phase systems (i.e., separation of rubber and plastic phases). The component with the lower proportion was found to be a dispersed phase in the major continuous matrix phase. Co-continuous phase morphology was also observed in the blend with the blend ratios of OENR/HDPE=50/50 and 60/40, where the materials behave as thermoplastic elastomers. The predictions using various models found that the phase inversion composition was in agreement with the experimental results. It was also found that the tensile strength, elongation at break, tension set and hardness properties were strongly dependent on the blend proportions.

Radical polymerization of methyl methacrylate in the presence of biodegradable poly(L-lactic acid). Preparation of blends, chemical-physical characterization and morphology

Poly(L-lactic) (PLLA)-based blends containing poly(methyl methacrylate) (PMMA) as dispersed phase are reported in the present paper. The blends are prepared by reactive (R-type blends) as well as non reactive (NR-type blends) methodologies, according to the preparation of the blends either polymerizing the acrylic monomer in the presence of PLLA or melt mixing the two polymers (PLLA and PMMA) in bulk. Thermal as well as morphological studies performed on both R and NR blends have revealed an intimate dispersion of PLLA and PMMA. Unlikely previous studies carried out on different aliphatic polyesters but following similar chemical approach, mechanical tests on the PLLA-based blends gave no satisfactory response for reactive-type blends. The results are interpreted on the basis of extensive cross-linking of the system caused by the high sensitivity of PLLA to radical attack. The copolymeric phase formed during the reactive blending is isolated and characterised by NMR technique.

Sorption and diffusion of aromatic penetrants into natural rubber blends

Sorption and diffusion of aromatic hydrocarbon penetrants through different NR blends such as NR/BIIR, NR/CIIR, NR/neoprene, NR/EPDM, NR/polybutadiene and NR/SBR have been studied. The diffusion coefficient ( D) of aromatic penetrants range from 6.8 to 84.3 × 10 −8 cm 2/s at a temperature range of 25–60°C. Transport data are affected by the nature of the interacting solvent molecule rather than its size and also by the structural variations of the elastomers blended with NR. Chlorobenzene and bromobenzene have shown higher transport data compared to nitrobenzene penetrant. The temperature dependence of the transport coefficient has been used to estimate the activation parameters from the Arrhenius plots. The activation parameters for the diffusion of aromatic penetrants range from 4.16 to 30.48 kJ/mol.