Mooney Viscosity Research Articles

Influence of filler system on the cure characteristics and mechanical properties of butyl reclaimed rubber

This research aimed to elucidate the effect of black and non-black filler systems on the cure characteristics and mechanical properties of butyl reclaimed rubber (BRR). In this study, BRR800 was the BRR investigated. Since reclaimed rubber is not entirely 100% rubber, actually being a mixture of rubber, carbon black, oil, zinc oxide, stearic acid and other compounding ingredients used in the original compounds, the reclaimed rubber content in each system was fixed at 161 parts per hundred (pphr). Each mixture was mixed using a two-roll mill. The fillers used in this study were carbon black and calcium carbonate. The Mooney viscosity, cure characteristics, crosslink density, and mechanical properties, such as hardness, abrasion resistance, compression set, tear strength, rebound resilience, and the tensile properties of the vulcanizates were investigated. The results showed that the Mooney viscosity of BRR800 filled with carbon black was increased effectively and had a faster curing time and higher crosslink density than BRR filled with calcium carbonate. In addition, except for compression set and elongation at break, the mechanical properties of BRR800 with a black filler system were higher than those of BRR800 with a non-black filler system.

The effect of mastication time on the physical properties and structure of natural rubber

The effect of mastication time in an internal mixer on the physical properties and microstructure of natural rubber (NR) was studied. The Mooney viscosity, plasticity, and complex viscosity reduced with increases in the mastication time due to the molecular breakdown of the rubber. The microstructural changes in the NR were studied using small-angle X-ray scattering. The results revealed that a reduction in the physical properties correlated with the structural changes, which occurred due to mastication. Increases in mastication time affected the distribution and size of the nonrubber component aggregations and the uniformity of the molecular structure of the NR.

Reducing and stabilizing the viscosity of natural rubber by using sugars: Interference of the Maillard reaction between proteins and sugars

AbstractThis work is an extension of previous work elucidating the reduction and stabilization of solid natural rubber (NR) viscosity by using sugars. Various amounts of glucose, fructose, sucrose, and maltose were incorporated into fresh NR (FNR), deproteinized NR (DPNR), and synthetic polyisoprene (IR) latexes. The results revealed that all sugars cannot decrease the Mooney viscosity of FNR, while only monosaccharides, that is, glucose and fructose, can significantly decrease the Mooney viscosity of both DPNR and IR by way of a lubrication mechanism. The proteins in FNR can diminish the capability of glucose and fructose to decrease the Mooney viscosity. Furthermore, glucose was found to reduce the occurrence of storage hardening in DPNR by interacting with polar groups of phospholipids at the rubber chain ends. Measurements of browning intensity as well as analysis of Maillard reaction products together with the NR protein–glucose model compound were utilized to confirm that the reduction and stabilization of the viscosity of NR using monosaccharides were interfered by the Maillard reaction between the proteins in NR and the monosaccharides.

Facile exfoliation method for improving interfacial compatibility in montmorillonite-natural rubber nanocomposites: A novel charge inversion approach

Montmorillonite (Mt) is a widely researched nano-filler in rubber compounds. Although, many methods have been reported to disperse Mt at nanoscale, up-to-date obtaining highest interfacial properties between the rubber matrix and the inorganic filler remains a challenge due to the lack of suitable preparation method to make stable dispersions of Mt. This study reports a novel, scalable and simple method to reinforce natural rubber (NR) with Mt achieving the highest degree of exfoliation and subsequently, offering high surface area for interactions between the filler and the rubber matrix. Stable cationic latex of NR was prepared by a charge inversion approach where NR latex was first treated with a quaternary ammonium surface active substance, n-hexadecyltrimethylammonium bromide (CTAB). Cationic NR latex thus prepared was directly coagulated using Mt aqueous dispersion as the coagulant. This coagulation approach facilitated the in-situ formation of a Mt-NR nanocomposite containing exfoliated and intercalated clay mineral platelets. Interfacial and stress-stain behavior of the un-vulcanized nanocomposite were further studied and compared with those of a nanocomposite prepared by the conventional latex compounding method (LCM). The results of powder X-ray diffraction (PXRD) and transmission electron microscopic (TEM) imaging of Mt-NR nanocomposite prepared via this process, confirmed that Mt platelets are exfoliated with in the rubber matrix. Further studies carried out using Mooney viscosity and green strength measurements proved that the interfacial interaction between the cationic latex and Mt was significantly improved compared to those of the nanocomposites prepared via latex compounding method.

Characterization of blends of virgin nitrile rubber and compounded nitrile rubber latex waste reclaimed with urea. Part 1: Cure characteristics

The objectives of this study were to develop a cost-effective, environmental-friendly, mechanochemical reclaiming process for compounded nitrile rubber (NBR) latex waste generated from the dipping and treatment plants of the glove manufacturing process and evaluate properties of reclaimed NBR and virgin NBR/reclaimed NBR blend compounds. Initially, compounded NBR latex waste containing NBR latex mixed with compounding ingredients was dried and reclaimed mechanically by varying the milling time from 0 min to 12.5 min at 2.5-min time interval. Properties such as initial plasticity, Mooney viscosity, swelling, and cross-link density of the mechanically reclaimed NBR samples were evaluated. Also, a series of mechanochemically reclaimed NBR samples were produced using urea and varying its amount from 0 phr to10 phr at 2 phr intervals and milling according to the selected milling time. The mechanochemically reclaimed NBR samples were also tested for the above properties. Finally, a reclaimed NBR sample was prepared by applying the best urea loading and the optimum milling time. Further, a series of virgin NBR/reclaimed NBR blend compounds was prepared by varying the reclaimed NBR from 0% to 70% at 10% interval. Cure characteristics of the above blend compounds were evaluated and compared with those of the 100% virgin NBR (control) compound. Initial plasticity and Mooney viscosity of mechanochemically reclaimed NBR revealed that urea is effective as a reclaiming agent for dried compounded NBR latex waste. Results in overall indicated that 5 min is the optimum milling time and 6 phr is the optimum loading of urea required to produce the best reclaimed NBR in terms of properties and energy consumption. Minimum torque and cure time of the 50:50 virgin NBR/reclaimed rubber blend compound were higher compared to the control, whereas scorch time, maximum torque, and cure rate index of the former were lower compared to the latter.

Effect of Gear Pump Extrusion Processing on the Properties of Fiber Reinforced Rubber Composites.

Short fiber reinforced rubber composites have been widely used in rubber products attributed to their excellent wear resistance. However, there are still some serious problems in the processing of short fiber reinforced rubber composites, such as Mooney viscosity increasing, temperature and extrusion pressure rising, and unstable extrusion quality. In particular, short fibers need to be extruded in a specific direction during the molding process, and the problems in this process are particularly prominent. In this manuscript, the influence of gear pump assisted extrusion on the properties of short fiber rubber composites is studied. The experimental results show that the application of a gear pump to assist extrusion could significantly increase the die pressure, reduce the extrusion temperature of the blend, and improve the extrusion efficiency and stability of the blend. Furthermore, it could improve the vulcanization efficiency, increase the tensile strength and tear strength of the compound, reduce wear, and guarantee the quality of extrusion products.

Unvulcanized Rubber Tape Made from Natural Rubber and Synthetic Polyisoprene Modified with Rosin as a Tackifier

This presented work was to study mechanical and tack properties of unvulcanized rubber tapes made from STR 20 and IR 2200 with various amount of carbon black and rosin as reinforcing agent and tackifier, respectively. Mixing process of solid rubbers and all chemicals was carried out by two roll mill machine. All rubber compounds were subjected to increasing the stickiness by aging under hot air at 150°C for 3 hours. From the experiment, green strength of the sticky rubber tape mixed with carbon black and rosin showed higher than that of the commercial rubber tape. The formulation exhibited the highest tensile stress at 400% strain is STR 20 mixed with 15 and 5 phr of carbon black and rosin, respectively. Mooney viscosity of the rubber tape made from STR 20 and IR 2200 was also reduced with the higher content of rosin. Although Mooney viscosity of the adhesive rubber tape normally decreased after heating under hot air, its tack property investigeted by rolling ball test on the surface predominantly became increased. Moreover, Mooney viscosity of the rubber tape made from IR 2200 would be remarkably enhanced by blending with only 20% of STR 20.

Ensemble Just-In-Time Learning-Based Soft Sensor for Mooney Viscosity Prediction in an Industrial Rubber Mixing Process

The lack of online sensors for Mooney viscosity measurement has posed significant challenges for enabling efficient monitoring, control, and optimization of industrial rubber mixing process. To obtain real-time and accurate estimations of Mooney viscosity, a novel soft sensor method, referred to as multimodal perturbation- (MP-) based ensemble just-in-time learning Gaussian process regression (MP-EJITGPR), is proposed by exploiting ensemble JIT learning. This method employs perturbations on similarity measure and input variables for generating the diversity of JIT learners. Furthermore, a set of accurate and diverse JIT learners are built through an evolutionary multiobjective optimization by balancing the accuracy and diversity objectives explicitly. Moreover, all base JIT learners are combined adaptively using a finite mixture mechanism. The proposed method is applied to an industrial rubber mixing process for Mooney viscosity prediction, and the experimental results demonstrate its effectiveness and superiority over traditional soft sensor methods.

Effect of Stabilizer States (Solid Vs Liquid) on Properties of Stabilized Natural Rubbers.

The main objective of this work is to study the effect of hydroxylamine sulfate or stabilizer states (solid vs liquid) on the storage hardening of natural rubber (NR). Several types of natural rubber samples were prepared: unstabilized NR samples and stabilized NR samples: (i) dry NR with 0.2 and 2.0 parts per hundred rubber (phr) of dry hydroxylamine sulfate, and (ii) natural latex with 0.2 and 2.0 phr of liquid hydroxylamine sulfate. The samples were characterized immediately (time 0) and after 12 weeks of storage at room temperature, respectively. We found that the Mooney viscosity, gel content, and Wallace plasticity of NR without a stabilizer increases with storage hardening for 12 weeks. However, two types of stabilized NR samples represent constant values of those three parameters, because hydroxylamine sulfate inhibits network and gel formation in NR. Interestingly, the mixing states (solid vs liquid) between natural rubber and the stabilizer affect the properties of stabilized NR. This could be explained by the better dispersion and homogeneous nature of liquid stabilizers in natural latex (liquid state), and thus the higher loading of the stabilizer in the liquid state. This is important, as the stabilization of NR properties as a function of time is required by rubber industry. This study is a utilization model from theory to application.

ENHANCING PERFORMANCE OF SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS BY APPLYING ORGANOCLAY AS SECONDARY FILLER

ABSTRACT Silica-reinforced natural rubber (NR) tire tread compounds are investigated using organoclay (OC) as secondary filler. By varying mixer temperature settings at a silica/OC ratio of 45/10 phr, dump temperatures are reached of approximately 120, 140, 150, and 160 °C. The increased dump temperature leads to a better silanization reaction resulting in lower mixing torque, Mooney viscosity, and Payne effect. The optimum mixing dump temperature was found to be around 150 °C. By varying the loadings of OC in the silica-filled NR compounds from 0 to 36 wt% relative to total filler amount, the increased OC loadings decreased the Payne effect and compound viscosities, significantly shortened scorch and cure times, and raised the tan delta at −20 and 0 °C as indications for ice traction and wet skid resistance of tire treads made therefrom. The optimum loading of OC of 9 wt% relative to total filler content shows better Payne effect, cure rate index, tan delta at −20 and 60 °C indicative for rolling resistance, and DIN (German Institute of Standardization) abrasion resistance index. The results indicate that the use of this hybrid filler may provide tires with better wet traction and lower rolling resistance and wear resistance compared with the pure silica-filled system.

Plasticization Effect of Bio-Based Plasticizers from Soybean Oil for Tire Tread Rubber.

Modified soybean oil (MSO) is synthesized from soybean oil (SO) and sulfur, aiming to reduce the double bond quantity of SO and avoid harmful effects on the crosslink density and mechanical properties of rubber. MSO modified with different weight percentages of sulfur is then used to plasticize tire tread rubber (TR). It is found that the crosslink density and modulus of MSO- plasticized rubber are significantly improved compared with that of SO-plasticized TR. MSO modified with 6 wt % sulfur (MSO-6%) exhibits the best plasticization effect on TR, thus, the plasticization effect of MSO-6% on TR was further studied by adjusting its additive content. Thereafter, the Mooney viscosity, Payne effect, mechanical property of different amount of MSO-6% plasticized TR are studied to investigate their plasticization effect. At the same additive content of plasticizer, the plasticization effect of MSO-6% and a commonly used aromatic hydrocarbon plasticizer (AO) is compared to determine the potential application of MSO on tire tread rubber. It is found MSO shows similar plasticization effect on TR compared with AO. More important, the aging resistance property and wear resistance property of MSO-6% plasticized rubber are better than those of AO-plasticized rubber. Therefore, MSO-6% is a promising bio-based plasticizer for tire tread rubber.

Effect of radiation-crosslinked polyester particles on wet mixing coprecipitated rubber for green tire

Solving the problems involved in processing wet mixing coprecipitated rubber is of great importance to develop high-performance green tires. In this work, the concept of polyester ball plasticized rubber is proposed to eliminate these processing difficulties using novel radiation-crosslinked polyester particles (REP). This paper describes a study of the effects of REP on the processability of wet mixing coprecipitated rubber compound and the mechanical properties of vulcanized rubber composites. Results indicate that REP lubrication untangles the rubber macromolecule during coprecipitated rubber processing; thus, reducing the Mooney viscosity and improving processability. Using 200 nm REP, the Mooney viscosity is reduced by 24% and the processing energy consumption is reduced by 10%. Additionally, REP can improve vulcanization efficiency and the mechanical properties of the vulcanized rubber composites. The application of REP in plasticizing coprecipitated rubber and reinforcing vulcanized rubber composites has theoretical importance in solving the problems of processing coprecipitated rubber and addressing the challenge of silica dispersal in tire tread composites for green tires.

Study of rubber/calcium carbonate composites

Fillers have been widely used in the rubber industry for many applications such as tile floor, vehicle tire, etc. Calcium carbonate (CaCO3) is one of the important inorganic powders and it is widely used as filler in order to reduce the cost in rubber industry. The objective of this study is to investigate physical and mechanical properties of the rubber composites with CaCO3 powder. We studied the CaCO3 additive in natural rubber (NR) with 25, 50, 75 and 100 parts per hundred rubber (phr). The effect of CaCO3 on the properties of rubber composite, such as Mooney viscosity, bound rubber, Mullins effect and Payne effect, was investigated. The result of Mullins effect of rubber composite filled with CaCO3 is in good agreement with the result of bound rubber: higher bound rubber leads to higher stress to pull the rubber composites. The Payne effect shows that the value of different storage moduli (ΔG’) of rubber compound filled with 25 phr CaCO3 is the lowest due to weaker filler network. While, the NR supplemented with 100 phr CaCO3 represents more significant ΔG’ with the strain increasing. This type of material could be applied for tailoring the properties of rubber products.

Effect of acrylonitrile butadiene rubber on the properties of silica-reinforced natural rubber

The effect of acrylonitrile butadiene rubber (NBR) as a compatibilizer in silica-reinforced natural rubber (NR) is studied. NBR, Emulcril 3380 with 32-34%, was various at 5, 10, 15, 20 and 25 part per hundred parts of rubber (phr) to be used as a compatibilizer for silica-filled NR. The use of NBR as a compatiblizer can improve cure time (T90), cure rate index (CRI), and Mooney viscosity of silica-filled NR compounds, but the re-agglomeration of filler still observes. The use of NBR does not show significantly effect on bound rubber contents. However, tensile strength, reinforcement index and tear strength are increased with increasing amount of NBR contents due to a presence of some rubber-filler interaction through acrylonitrile groups of NBR and silanol groups on the silica surface. It leads to observe more surface roughness on tensile fractured surfaces.

The effect of hydroxylamine sulfate on the storage hardening of natural rubber

Natural rubber (NR) consists of rubber and non-rubber components, which is mostly cis-1, 4-polyisoprene. The main non-rubber components are proteins and phospholipids which are attached at each end of the NR chains. If we store NR for prolong period, the proteins and phospholipids promote formation of a NR network. This causes the gel formation with increasing the Mooney viscosity of NR, and this is called storage hardening. The objective of this work is to study the effect of hydroxylamine sulfate on the storage hardening of natural rubber. Three types of natural rubber sample were prepared: pure NR, NR with 0.2 phr of hydroxylamine sulfate, and NR with 2.0 phr of hydroxylamine sulfate. Samples were characterized immediately (time 0) and after 12 weeks of storage at room temperature. We found that gel content and Mooney viscosity of NR without hydroxylamine sulfate are increased with the storage hardening for 12 weeks. However, both NR samples with hydroxylamine sulfate represent constant viscosity values because hydroxylamine sulfate inhibits the network and gel formation in NR. This is important as the stabilization of NR properties in the function of time is required by rubber industry.

Effect of alternative filler from glass industry on the selected properties of friction polymer matrix in automotive industry

This paper is focused on the preparation of polymer blends with addition of alternative filler from glass industry in various granularity (>40 µm, 40–32 µm, 32–25 µm, 25–0 µm). The polymer matrix (PMX3) consists of melamine resin, phenolic resin and nitrile rubber. This polymer matrix composition is commonly applied in friction composite systems in automotive industry. The surface activity of various filler fractions was studied. The rheological properties, such as minimum torque, maximum torque, optimum vulcanization time and scorch time of prepared friction polymer matrix were tested, using the PRPA 2000 rheometer. Mooney viscosity of new prepared polymer matrix was studied with help of Mooney Viscosimetr 91.03 Gottert testing machine.

Robust Soft Sensor with Deep Kernel Learning for Quality Prediction in Rubber Mixing Processes.

Although several data-driven soft sensors are available, online reliable prediction of the Mooney viscosity in industrial rubber mixing processes is still a challenging task. A robust semi-supervised soft sensor, called ensemble deep correntropy kernel regression (EDCKR), is proposed. It integrates the ensemble strategy, deep brief network (DBN), and correntropy kernel regression (CKR) into a unified soft sensing framework. The multilevel DBN-based unsupervised learning stage extracts useful information from all secondary variables. Sequentially, a supervised CKR model is built to explore the relationship between the extracted features and the Mooney viscosity values. Without cumbersome preprocessing steps, the negative effects of outliers are reduced using the CKR-based robust nonlinear estimator. With the help of ensemble strategy, more reliable prediction results are further obtained. An industrial case validates the practicality and reliability of EDCKR.

The curing characteristics and tear properties of phenolic resin on chloroprene rubber vulcanizate

Chloroprene rubber (CR) is synthetic rubber widely used for seal, joint, and also adhesive. For making rubber product, additives are needed and it can influence the properties of vulcanizates. This study aims to determine the curing characteristics and mechanical properties of chloroprene vulcanizate. The chloroprene vulcanizates were prepared by compounding with the two-roll mill and vulcanizing with the hydraulic press. Phenolic resin used as additives were varies i.e: 0, 10, 20, and 30 phr. The curing characteristics of the CR vulcanizates were studied by rheometer at 140 °C, 150 °C, and 160 °C. The tear properties of the CR vulcanizates were studied by tensile strength tester. The phenolic resin improves the mooney viscosity, scorch time and optimum curing time. The compound without phenolic resin gives the highest mooney viscosity and optimum curing time. The 10 phr phenolic resin give the best mooney viscosity, optimum curing time, constant rate, activation energy and also tear strength. The suitable curing temperature for CR compound is at 150 °C and the proper additive for CR vulcanizate is 10 phr phenolic resin.

Elastomeric Compounds with Fine-Grained Carbonic Additives

The influence of three different nanomaterials (nonfunctionalized and functionalized with amino and oxygencontaining groups) forming a part of elastomeric compounds based on a natural SMR-10 rubber and a butadienenitrile BNKS-18 rubber on the interfacial interactions of these rubbers with an active and a semiactive carbons blacks added to them was investigated. For the purpose of estimating the action of the indicated nanomaterials incorporated into the composition of a rubber on its properties and the interaction of the rubber with a carbon black introduced into the compound, investigations have been performed on determination of the bound rubber in such a compound, the qualitative characteristics of the distribution of an extender in it (the modulus of elasticity and the shear modulus of the compound in the cases of its small and large deformations, respectively, and the difference between these moduli representing the complex dynamic modulus of the compound), and its Mooney viscosity.

Влияние пластикации изопренового каучука на вязкость по Муни резиновой смеси на его основе

Влияние пластикации изопренового каучука на вязкость по Муни резиновой смеси на его основе