CHARACTERIZATION AND CORRELATION OF THE NETWORK CHAIN DENSITY TO THE PROPERTIES OF FLUOROELASTOMER RUBBER

2020 ◽  
Vol 93 (2) ◽  
pp. 274-285 ◽  
Author(s):  
M. Boyd ◽  
I. Therrien ◽  
Richard. J. Pazur
Keyword(s):  
Crosslink Density ◽  
Double Quantum ◽  
Steady Increase ◽  
Intensity Data ◽  
Network Chain ◽  
Elongation At Break ◽  
Compression Set ◽  
Low Field ◽  
Subsequent Application ◽  
Corrected Intensity

ABSTRACT The concentrations of triallyl isocyanurate (TAIC) in a peroxide-curable fluoroelastomer terpolymer containing 67 wt% of fluorine were varied to generate compounds of differing crosslink densities. Experimental analysis was undertaken using rheometry, hardness, stress–strain (Mooney–Rivlin), equilibrium solvent swell, and low-field nuclear magnetic resonance (NMR) using the double quantum (DQ) technique. Increasing the TAIC concentration caused a systematic rise in rheometry elastic torque, hardness, and tensile strength, whereas both elongation at break and swelling levels decreased. These results are concurrent with an enhanced overall level of crosslinking, which was confirmed by the steady increase of the Mooney–Rivlin C1 values. DQ NMR analysis using hydrogen and fluorine probes and subsequent application of fast Tikhonov regularization to the corrected intensity data were particularly useful in discerning the inhomogeneous nature of the compound morphology. The spatial distribution of the crosslink density suggests that the compound consists of small, highly crosslinked/entangled polymerized TAIC domains embedded within the elastic crosslinked matrix. A concentration of 3 phr of TAIC is optimal according to compression set testing.

HEAT AGING OF A BROMOBUTYL TIRE INNER LINER UNDER AEROBIC AND ANAEROBIC CONDITIONS

2021 ◽  
Author(s):  
M. Yerxa ◽  
C. Porter ◽  
R. J. Pazur
Keyword(s):  
Crosslink Density ◽  
Chain Scission ◽  
Double Quantum ◽  
Elongation At Break ◽  
Small Areas ◽  
Diffusion Limited ◽  
Low Field ◽  
Aging Conditions ◽  
Crosslinking Reactions ◽  
Aerobic And Anaerobic

ABSTRACT A bromobutyl tire inner liner compound was prepared and subjected to aerobic and anaerobic heat aging at a temperature of 100 °C for seven aging times up to 8 weeks. Hardness and mechanical properties were monitored, and the evolution of the crosslink density was followed using equilibrium solvent swell and low field double quantum (DQ) nuclear magnetic resonance (NMR). The hardness and the 300% tensile stress increased with heat aging, while both tensile strength and elongation at break dropped. Both chain scission and crosslinking reactions were taking place. Equilibrium swelling and DQ NMR results confirmed that a larger crosslink density increase was seen under aerobic versus anaerobic aging conditions. The network distribution consisting of a dominant low crosslinking zone and small areas of higher crosslinking slowly broadened and shifted toward higher crosslink densities upon heat aging. The compounds aged heterogeneously. Attenuated total reflectance–Fourier transform infrared spectroscopy confirmed the presence of an oxidized surface layer, and therefore diffusion-limited oxidation effects, but only under aerobic aging conditions. Reaction mechanisms are proposed to explain the net crosslink rise with heat aging.

Application of NR-Based Latex Reclaim: The Link Between Structure and Properties

2007 ◽  
Vol 80 (1) ◽  
pp. 40-60 ◽  
Author(s):  
W. K. Dierkes ◽  
V. V. Rajan ◽  
J. W. M. Noordermeer ◽  
R. Joseph
Keyword(s):  
Viscoelastic Properties ◽  
Crosslink Density ◽  
Virgin Material ◽  
Structure And Properties ◽  
Elongation At Break ◽  
Rubber Blends ◽  
Compression Set ◽  
Vulcanized Rubber ◽  
The Matrix ◽  
Property Profile

Abstract Natural rubber based waste latex rubber (WLR) that is reclaimed with diphenyldisulphide by a thermo-mechanical process is blended with virgin rubber in different proportion to study the change in mechanical and viscoelastic properties. Two types of WLR differing mainly in the amount of polysulfidic linkages are reclaimed and blended with a virgin rubber compound with and without adjustment of the curing system, the former in order to compensate for the extra input of sulfur and accelerators due to the addition of reclaim. The cure behavior, final crosslink density and distribution, mechanical properties and dynamic viscoelastic properties of the blends with reclaimed WLR are compared to the property profile of the virgin material. The morphology of the blends as well as sulfur distribution between the matrix and the reclaim particle is analyzed. With increasing concentrations of WLR reclaim, tensile strength, tear strength and elongation at break decrease, whereas modulus at 100% elongation, compression set and hardness show an increase. The storage modulus of the vulcanized rubber blends decreases with increasing WLR reclaim content in the blend. Swelling measurements show that the crosslink density is reduced for the adjusted cure system but increased for a fixed cure system. These influences of reclaimed WLR on the property profile of a virgin compound will be discussed fundamentally in terms of morphology and crosslink distribution.

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

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6045-6060
Author(s):  
Zafirah Zainal Abidin ◽  
Siti Nur Liyana Mamauod ◽  
Siti Salina Sarkawi ◽  
Nurshamimi Shahirah Binti Saimi
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Crosslink Density ◽  
Rubber Content ◽  
Elongation At Break ◽  
Cure Characteristics ◽  
Compression Set ◽  
Roll Mill ◽  
Mooney Viscosity

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.

Tensile Strength of Gum and Reinforced EPR and SBR Vulcanizates

1964 ◽  
Vol 37 (4) ◽  
pp. 818-825 ◽  
Author(s):  
T. J. Dudek ◽  
F. Bueche
Keyword(s):  
Tensile Strength ◽  
Temperature Dependence ◽  
Crosslink Density ◽  
Tensile Force ◽  
Creep Rupture ◽  
Rate Dependence ◽  
Degree Of Cure ◽  
Equilibrium Conditions ◽  
Network Chain ◽  
Elongation At Break

Abstract The tensile strength and elongation at break of EPR and SBR gum vulcanizates were determined as a function of network chain density. A large viscous contribution to the tensile force was found at low crosslink density, and the maximum in the tensile strength versus chain density curve decreased as more nearly equilibrium conditions were approached. The rate dependence of tensile strength of black-filled EPR was studied by creep rupture experiments. The temperature dependence of the tensile strength of filled EPR and SBR was studied and compared. The same limiting degree of cure was obtained for both filled and gum vulcanizates of EPR.

Role of Hydroxyl-Terminated Polybutadiene in Changing Properties of EPDM/ENR Blends

2013 ◽  
Vol 844 ◽  
pp. 349-352 ◽  
Author(s):  
Sarawut Prasertsri ◽  
Passakorn Amnuay ◽  
Khanitta Sripan ◽  
Pranee Nuinu
Keyword(s):  
Thermal Aging ◽  
Crosslink Density ◽  
Aging Treatment ◽  
Elongation At Break ◽  
Compression Set ◽  
The Poor ◽  
Cure Time ◽  
Ethylene Propylene Diene Rubber ◽  
Diene Rubber

In this research, the effect of hydroxyl-terminated polybutadiene (HTPB) on processability, mechanical properties, thermal aging and oil resistance of 80/20 ethylene-propylene diene rubber/epoxidized natural rubber (EPDM/ENR) blend was investigated. The amount of HTPB used was varied from 0-4 parts per hundred of rubber (phr). The results revealed that addition of HTPB into EPDM/ENR blend decreased the compound viscosity, while scorch time and cure time slightly increased with increasing HTPB content. Furthermore, hardness, tensile and tear strengths of the blend decreased due to the poor dispersion of fillers in the presence of HTPB. After thermal aging treatment, the crosslink density of all EPDM/ENR blends increased leading to increasing in 100% modulus, tensile strength and swelling resistance, as well as reducing in elongation at break. However, it had additional plus features that high resilience with low compression set was achieved in the blend containing 2 phr of HTPB.

scholarly journals The effects of alkanolamide addition on cure characteristics, swelling behaviour and tensile properties of silica-filled natural rubber (NR) / chloroprene rubber (CR) blends

2018 ◽  
Vol 34 ◽  
pp. 01030 ◽  
Author(s):  
Indra Surya ◽  
Syahrul Fauzi Siregar ◽  
Hanafi Ismail
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Crosslink Density ◽  
Tensile Modulus ◽  
Palm Stearin ◽  
Swelling Behaviour ◽  
Elongation At Break ◽  
Cure Characteristics ◽  
Chloroprene Rubber

Effects of alkanolamide (ALK) addition on cure characteristics, swelling behaviour and tensile properties of silica-filled natural rubber (NR)/chloroprene rubber (CR) blends were investigated. The ALK was synthesized from Refined Bleached Deodorized Palm Stearin (RBDPS) and diethanolamine, and incorporated into the silica-filled NR/CR blends as a non-toxic rubber additive. The ALK loadings were 0.0, 1.0, 3.0, 5.0 and 7.0 phr. It was found that the ALK exhibited shorter scorch and cure times and higher elongation at break of the silica-filled NR/CR blends. The ALK also exhibited higher torque differences, tensile modulus and tensile strength at a 1.0 phr of ALK loading and then decreased with further increases in the ALK loading. The swelling measurement proved that the 1.0 phr loading of ALK caused the highest degree in crosslink density of the silica-filled NR/CR blends.

scholarly journals Curing and mechanical properties of chlorosulphonated polyethylene rubber blends

2011 ◽  
Vol 17 (3) ◽  
pp. 315-321 ◽  
Author(s):  
Gordana Markovic ◽  
Vojislav Jovanovic ◽  
Suzana Samarzija-Jovanovic ◽  
Milena Marinovic-Cincovic ◽  
Jaroslava Budinski-Simendic
Keyword(s):  
Mechanical Properties ◽  
Crosslink Density ◽  
Hydraulic Press ◽  
Elongation At Break ◽  
Rubber Blends ◽  
Tensile Tester ◽  
Roll Mill ◽  
Cure Time ◽  
Chlorosulphonated Polyethylene ◽  
Scanning Electron

In this paper the curing and mechanical properties of two series of prepared blends, i.e., chlorosulphonated polyethylene (CSM)/isobutylene-co-isoprene (IIR) rubber blends and chlorosulphonated polyethylene (CSM)/chlorinated isobutylene-co-isoprene (CIIR) rubber blends were carried out. Blends were prepared using a two roll-mill at a temperature of 40-50?C. The curing was assessed by using a Monsanto Oscillating Disc Rheometer R-100. The process of vulcanization accelerated sulfur of pure rubbers and their blends was carried out in an electrically heated laboratory hydraulic press under a pressure of about 4 MPa and 160?. The stress-strain experiments were performed using tensile tester machine (Zwick 1425). Results indicate that the scorch time, ts2 and optimum cure time, tc90 increase with increasing CSM content in both blends. The values of modulus at 100% and at 300% elongation and tensile strength increases with increasing CSM content, whereas elongation at break shows a decreasing trend. The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement and scanning electron microscopy studies of the rubber blends fractured surfaces.

Effect of Ground Vulcanizate Modification Methods on Properties of Oil-Petroleum-Resistant Rubber

2021 ◽  
Vol 903 ◽  
pp. 127-133
Author(s):  
Vadim Myadelets ◽  
Vjaceslavs Lapkovskis ◽  
Andrey V. Kasperovich
Keyword(s):  
Chemical Nature ◽  
Nitrile Rubber ◽  
Rubber Crumb ◽  
Elongation At Break ◽  
Compression Set ◽  
Peg 400 ◽  
Peg 4000 ◽  
Modification Method ◽  
Resistant Rubber ◽  
Set Up

In this paper, the influence of the modification method applied to ground vulcanizate (GV) on the properties of elastomeric compositions based on nitrile rubber is discussed. Modified GV has been mixed with the elastomeric composition, which is used for the manufacturing of oil-petroleum-resistant rubber products.The work takes into consideration two types of GV with different chemical nature. The first GV type is rubber crumb produced from end-of-life tires. The second GV type was obtained from rubber wastes based on nitrile rubber. Three methods of the modification are compared in the research: mechanical activation in a planetary ball mill, swelling in a Polyethylene glycol (PEG-400) medium, and the mechano-chemical transformation of GV with PEG-4000. It is shown that depending on the dosage addition of GV modified with PEG-4000 reduce the compression set up for (16.1±0.7%), the strength decreases only by 2.1–8.3%, and the elongation at break increases by 0.8–10.3% compared to rubber without additives.

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