A Low Modulus, High Fatigue Life Elastomer Compound for Suspension Applications

1981 ◽  
Vol 54 (2) ◽  
pp. 347-365 ◽  
Author(s):  
Paul C. Killgoar ◽  
Marvin A. Lemieux ◽  
Ronald J. Tabar
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Natural Rubber ◽  
Temperature Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Compression Set ◽  
High Fatigue ◽  
Current Production ◽  
Low Modulus ◽  
New Compounds

Abstract Soft elastomeric suspension bushing compounds have been developed which are based on natural rubber/polybutadiene (NR/BR) blends which have been softened with polyisobutylene (IM). The new compounds have a Shore A hardness of 45 and a fatigue life of 97 kc and 80 kc for the urethane cured and semi-EV cured compounds respectively. This compares with a fatigue life of 62 kc for the current production compound (Shore A 65). It appears that the mechanical behavior, i.e. resistance to crack growth, of natural rubber based compounds is unaffected by the addition of IM. Fatigue life, compression set and retention of physical properties after heat aging of the new compounds are also superior to the production compound. The dynamic mechanical properties of the new compounds were evaluated and found to have a slightly greater temperature sensitivity than the production compounds.

Low Modulus, High Damping, High Fatigue Life Elastomer Compounds for Vibration Isolation

1984 ◽  
Vol 57 (4) ◽  
pp. 792-803 ◽  
Author(s):  
Marvin A. Lemieux ◽  
Paul C. Killgoar
Keyword(s):  
Fatigue Life ◽  
Vibration Isolation ◽  
Fatigue Properties ◽  
Copolymer Blends ◽  
High Fatigue ◽  
Low Modulus ◽  
Shelf Life Stability ◽  
Cure Temperature ◽  
New Compounds ◽  
Good Heat

Abstract NR/BR/NIR copolymer blends were found to be too stiff at low temperatures for many potential isolation applications. Soft compounds have been developed which exhibit high damping, long fatigue life, and good heat resistant properties. These compounds are based on NR/BIIR blends with IM as a diluent. The new compounds are cured with a semi-EV cure system. The morphology appears to be an important factor controlling the fatigue properties of the blends. Fatigue life can be affected by the cure temperature, molecular weight of the IM used, and by the use of amine anti-oxidants. For improved processing and shelf-life stability, the use of amine anti-oxidants is not recommended.

Calophyllum Inophyllum Oil as Plasticizer in Natural Rubber Compounds

2009 ◽  
Vol 25 (2) ◽  
pp. 113-128 ◽  
Author(s):  
P. Raju ◽  
V. Nandanan ◽  
Sunil K.N. Kutty
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Thermal Studies ◽  
Calophyllum Inophyllum ◽  
Compression Set ◽  
Peak Rate ◽  
Rubber Compounds ◽  
Cure Time ◽  
Calophyllum Inophyllum Oil ◽  
Control Compound

Mechanical properties and the thermal degradation characteristics of natural rubber compounds with calophyllum inophyllum oil were compared to that of the control compound containing naphthenic oil. The compounds containing calophyllum inophyllum oil showed improved tensile strength, tear strength, modulus, compression set, abrasion resistance and resilience. Cure time was higher than the naphthenic oil mixes. Thermal studies showed an increase of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in temperature at which the peak rate of degradation occurred. The peak rate of degradation was comparable to the control mix containing naphthenic oil.

Development of a High Strength Mg-Zn-Y-Zr Wrought Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 1701-1706
Author(s):  
Rong Shi Chen ◽  
Wei Neng Tang ◽  
Dao Kui Xu ◽  
En Hou Han
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Fatigue Life ◽  
Deformation Behavior ◽  
Fatigue Behavior ◽  
High Strength ◽  
Zn Content ◽  
High Fatigue ◽  
Content Range ◽  
Zr Alloy

The effects of Y addition to the Mg-Zn-Y-Zr alloy on the change of the microstructure and the mechanical properties (with the Y content range of 1 to 3 wt%) have been investigated. It shows that when Zn content is constant (5.65wt%), the alloys with Y content between 1.17 and 1.72wt% nearly reach its highest strength. With the composition near the optimums, the extruded Mg-6%Zn-1%Y-Zr alloy shows high strength and excellent ductility. The deformation behavior of this new alloy at high temperature has also been studied. Moreover, the super-long fatigue behavior of the Mg-6%Zn-1%Y-Zr alloy has also been tested, the results show the alloy with a high fatigue strength of about 85-90MPa in the super-long fatigue life regime of 1×109 cycles.

Effect of Ashes as Biomass in Silica Filled Natural Rubber

2017 ◽  
Vol 735 ◽  
pp. 153-157
Author(s):  
Wasinee Pinpat ◽  
Wirunya Keawwattana ◽  
Siree Tangbunsuk
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Rice Husk Ash ◽  
Silica Content ◽  
Elongation At Break ◽  
Compression Set ◽  
Cure Time ◽  
Oil Palm Ash ◽  
Reinforcing Filler

Silica has been used as reinforcing filler in natural rubber for a period of time as it results in excellent properties for NR vulcanizes. Rice husk ash (RHA), bagasse ash (BA), and oil palm ash (OPA) obtained from agricultural wastes are mainly composed of silica in the percentage of 80.00%, 57.33%, and 40.20% by weight, respectively. The effect of these fillers on cure characteristics and mechanical properties of natural rubber materials at fixed silica content at 35 parts per hundred of rubber (phr) were investigated. The results indicated that ashes showed greater cure time compared to that of the silica. The incorporation of ashes into natural rubber gradually improved compression set but significantly decreased tensile strength, elongation at break, and resilience. Moreover, young's modulus increased, while hardness showed no significant change with the addition of ashes. Overall results indicated that ashes could be used as cheaper fillers for natural rubber materials where improved mechanical properties were not critical.

ARAMID–NYLON 6.6 HYBRID CORDS AND INVESTIGATION OF THEIR PROPERTIES

2012 ◽  
Vol 85 (2) ◽  
pp. 180-194 ◽  
Author(s):  
Berrin Yilmaz
Keyword(s):  
Mechanical Properties ◽  
Linear Density ◽  
Thermally Stable ◽  
High Modulus ◽  
Synthetic Yarn ◽  
Product Property ◽  
High Fatigue ◽  
High Elongation ◽  
Low Modulus ◽  
Twist Level

Abstract Hybrid cords of two different polyamide yarns, poly(p-phenylene terephthalamide; aramid) and poly(hexamethylene adipamide; nylon 6.6) have been investigated. Aramid is a high-tenacity, high-modulus, low-elongation, and thermally stable yarn material. Nylon 6.6 is a high-elongation, low-modulus, high-fatigue-resistant, and good adhering synthetic yarn. The combination of these two different synthetic yarns enables hybrid cords with a diversified range of mechanical properties. The hybrid cord product property diversification is achieved by proper combination of different cord-forming properties of individual plies, such as linear densities, twist levels, ply numbers, treating conditions, and so forth. The effect of linear densities, twist level of plies, and twist level of cabled cord and ply number on the cord properties and also cord performance have been summarized. Aramid yarn having an 1100 linear density has been combined with nylon 6.6 yarn with a different linear density, ranging from 940 to 2100, to form hybrid cord structures. Twisting of aramid and nylon 6.6 yarns has been kept between 150 and 450 twists per meter, while the ply number of aramid and nylon 6.6 yarns has been varied as one and two plies by keeping the total ply number of the cord as three.

scholarly journals Dynamic Mechanical Properties of Vietnam Modified Natural Rubber via Grafting with Styrene

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
T. A. Dung ◽  
N. T. Nhan ◽  
N. T. Thuong ◽  
D. Q. Viet ◽  
N. H. Tung ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Graft Copolymer ◽  
Graft Copolymerization ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Tert Butyl Hydroperoxide ◽  
Wide Range ◽  
Redox Initiator ◽  
Tetraethylene Pentamine

The dynamic mechanical behavior of modified deproteinized natural rubber (DPNR) prepared by graft copolymerization with various styrene contents was investigated at a wide range of temperatures. Graft copolymerization of styrene onto DPNR was performed in latex stage using tert-butyl hydroperoxide (TBHPO) and tetraethylene pentamine (TEPA) as redox initiator. The mechanical properties were measured by tensile test and the viscoelastic properties of the resulting graft copolymers at wide range of temperature and frequency were investigated. It was found that the tensile strength depends on the grafted polystyrene; meanwhile the dynamic mechanical properties of the modification of DPNR meaningfully improved with the increasing of both homopolystyrene and grafted polystyrene compared to DPNR. The dynamic mechanical properties of graft copolymer over a large time scale were studied by constructing the master curves. The value of bT has been used to prove the energetic and entropic elasticity of the graft copolymer.

scholarly journals Proper Blends of Biodegradable Polycaprolactone and Natural Rubber for 3D Printing

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2416
Author(s):  
Thossapit Wissamitanan ◽  
Charoenyutr Dechwayukul ◽  
Ekwipoo Kalkornsurapranee ◽  
Wiriya Thongruang
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Natural Rubber ◽  
Shape Recovery ◽  
Fused Deposition Modeling ◽  
Melt Flow ◽  
Melt Flow Rate ◽  
Fused Deposition ◽  
Compression Set ◽  
Deposition Modeling

Flexible thermoplastic elastomers (TPE) were prepared for fused deposition modeling (FDM) or 3D printing. These materials can be used for medical purposes such as disposable soft splints and other flexible devices. Blends of 50% epoxidized natural rubber (ENR-50) and block rubber (Standard Thai Rubber 5L (STR5L)) with polycaprolactone (PCL) were produced and compared. The purpose of this study was to investigate the properties of natural rubber (NR) and PCL in simple blends with PCL contents of 40%, 50%, and 60% by weight (except at 75% for morphology study) in the base mixture (NR/PCL). The significant flow factors for FDM materials, such as melting temperature (Tm) and melt flow rate (MFR), were observed by differential scanning calorimetry (DSC) and via the melt flow index (MFI). In addition, the following mechanical properties were also determined: tensile strength, compression set, and hardness. The results from DSC showed that the melting temperature changed slightly (1–2 °C) with amount of PCL used, and there was a suspicious point in the 50/50 blends with both types of rubber. The lowest melting enthalpy of both blends was found at the 50/50 blended composition. The MFI results showed that PCL significantly affected the melt flow rate of both blends. The ENR-50/PCL blend flowed better than the STR5L/PCL blend. The conclusion was that this was due to the morphology of its phase structure having better uniformity than that of the STR5L/PCL blend. In compression set testing or measuring shape recovery, rubber directly influenced the recovery in all blends. The ENR-50/PCL blend had less recovery than the STR5L/PCL blend, probably due to the functional effects of epoxide groups and polarity mismatch. The hard phase PCL significantly affected the hardness of samples but improved shape recovery of the material. The ENR-50/PCL blend had better tensile properties than the STR5L/PCL blend. The elongation at break of both blends improved with a high rubber content. Hence, the ENR-50/PCL blend was superior to STR5L/PCL for printing purposes due to its better miscibility, uniformity, and flow, which are the keys to success for optimizing the fused deposition modeling conditions as well as the overall mechanical properties of products. Most blends in this study were only slightly different, but the 50/50 blend of ENR-50/PCL seemed to be near optimal for 3D printing.

Kinetics of Peroxide Vulcanization of Natural Rubber

2012 ◽  
Vol 28 (4) ◽  
pp. 201-220 ◽  
Author(s):  
Rejitha Rajan ◽  
Siby Varghese ◽  
K.E. George
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Crosslinking Agent ◽  
Decomposition Reaction ◽  
Dominant Factor ◽  
Compression Set ◽  
Cure Time ◽  
Minimum Residual ◽  
Vulcanization Kinetics ◽  
Kinetics Of

This study was undertaken to optimize the vulcanization conditions and explore the effect of residual peroxide in the peroxide vulcanization of natural rubber. The study was followed through the kinetics of the vulcanization reaction at various temperatures viz. 150,155,160 and 165°C. Dicumyl peroxide (DCP) was used as the crosslinking agent. The Monsanto Rheometer was used to investigate the different crosslinking stages and vulcanization kinetics. The thermal decomposition of peroxide followed a first order free radical decomposition reaction. Half-lives at various temperatures were determined. The percentage of residual peroxide was calculated from the cure kinetic data. The effect of residual peroxide on mechanical properties was studied at various peroxide levels and also by extending the cure time (from t90 to t95 and then to t100). Mechanical properties such as tensile strength, elongation at break, modulus and compression set (70 and 100°C) were measured. Excess peroxide was found to cause a high compression set at elevated temperature and the cure time was selected to achieve minimum residual peroxide in the product. Results indicate that peroxide concentration is the dominant factor controlling the crosslink density and hence the properties of the vulcanizates.

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