Influence of thermal-oxidative aging on the mechanical performance and structure of cold-mixed epoxy asphalt

2022 ◽  
pp. 130482
Author(s):  
Jingjing Si ◽  
Junyan Wang ◽  
Xin Yu ◽  
Gongying Ding ◽  
Wei Ruan ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Oxidative Aging ◽  
Epoxy Asphalt ◽  
Thermal Oxidative Aging

EV Systems for NR. II. Further Development of Curing Systems and Vulcanizate Properties

1969 ◽  
Vol 42 (2) ◽  
pp. 418-440 ◽  
Author(s):  
R. M. Russell ◽  
T. D. Skinner ◽  
A. A. Watson
Keyword(s):  
Thermal Stability ◽  
Zinc Oxide ◽  
Fatigue Cracking ◽  
Oxide System ◽  
Oxidative Aging ◽  
Thermal Oxidative Aging ◽  
Further Development ◽  
Resistance To Heat ◽  
Thermal Stability Of ◽  
Simple Network

Abstract It was shown in Part I that the use of EV systems in NR provides a simple network in which the crosslinks are mainly monosulfidic. Part II describes in some detail the properties of vulcanizates obtained by the use of EV systems and their relationship to conventional and TMTD-zinc oxide cured vulcanizates. The disadvantages of short scorch time and heavy bloom which accompany the TMTD-zinc oxide system are overcome by the new EV systems. The monosulfidic network obtained by the use of EV systems confers on NR good overall physical properties together with much improved resistance towards thermal and thermal oxidative aging. The thermal stability of this type of network is reflected in the outstanding resistance of the vulcanizates to set and reversion, and their good resistance to heat build-up under dynamic conditions. Vulcanizates derived from EV systems have increased resistance to thermal oxidative aging due to the inherent thermal stability of the networks and good response to antioxidant protection. This increased resistance results in much better retention of tensile properties, tear resistance and fatigue cracking resistance on aging, relative to that of conventionally cured vulcanizates.

Effects of thermal cycling on phenylethynyl-terminated PMDA-type asymmetric polyimide composites

2018 ◽  
Vol 31 (7) ◽  
pp. 861-871
Author(s):  
Yixiang Zhang ◽  
Masahiko Miyauchi ◽  
Steven Nutt
Keyword(s):  
Thermal Cycling ◽  
Mechanical Degradation ◽  
Thermal Cycles ◽  
Oxidative Aging ◽  
Short Beam ◽  
Beam Shear ◽  
Thermally Driven ◽  
The Matrix ◽  
Service Environments ◽  
Thermal Oxidative Aging

The effects of thermal cycling on a polymerized monomeric reactant (PMR) type polyimide (TriA X) reinforced with carbon fibers were investigated. Composite specimens were subjected to 2000 thermal cycles between −54°C and 232°C. At 400-cycle intervals, laminates were inspected for microcracks, and glass transition temperature ( T g) and short-beam shear (SBS) strength were measured. The composites did not exhibit microcracks after thermal cycling, although after 2000 thermal cycles, mechanical properties of the matrix declined slightly. The matrix degradation decreased the resistance to microcracking upon further loading. No effects of thermal oxidative aging were observed from thermal cycling, and thermally driven fatigue and creep were identified as the primary and secondary factors inducing mechanical degradation of the matrix. T g of the composites exhibited no change after 2000 cycles, while the SBS strength decreased slightly (3–9%). The results highlight the potential for use of TriA X composites as long-term structural components in high-temperature service environments.

scholarly journals Thermal Degradation Studies of a Polyurethane Propellant Binder

2000 ◽  
Vol 73 (4) ◽  
pp. 678-693 ◽  
Author(s):  
M. Celina ◽  
A. C. Graham ◽  
K. T. Gillen ◽  
R. A. Assink ◽  
L. M. Minier
Keyword(s):  
Tensile Elongation ◽  
Polymer Network ◽  
Nmr Relaxation ◽  
Oxidative Aging ◽  
Oxidation Rates ◽  
Highly Sensitive ◽  
Arrhenius Diagram ◽  
Network Properties ◽  
Dominant Process ◽  
Thermal Oxidative Aging

Abstract The thermal oxidative aging of a crosslinked hydroxy-terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) based polyurethane rubber, used as a polymeric binder in solid propellant grain, was investigated at temperatures from 25 to 125 °C. The changes in tensile elongation, polymer network properties and chain dynamics, mechanical hardening and density were determined with a range of techniques including modulus profiling, solvent swelling, NMR relaxation and O2 permeability measurements. We critically evaluated the Arrhenius methodology that is commonly used with a linear extrapolation of high temperature aging data using extensive data superposition and highly sensitive oxygen consumption experiments. The effects of other constituents in the propellant formulation on aging were also investigated. We conclude that crosslinking is the dominant process at higher temperatures and that the degradation involves only limited hardening in the bulk of the material. Significant curvature in the Arrhenius diagram of the oxidation rates was observed. This is similar to results for other rubber materials.

Thermal-oxidative aging behavior of nitrile-butadiene rubber/functional LDHs composites

2016 ◽  
Vol 133 ◽  
pp. 219-226 ◽  
Author(s):  
Xianru He ◽  
Tianxiang Li ◽  
Zhengren Shi ◽  
Xin Wang ◽  
Fei Xue ◽  
...  
Keyword(s):  
Butadiene Rubber ◽  
Aging Behavior ◽  
Oxidative Aging ◽  
Nitrile Butadiene Rubber ◽  
Thermal Oxidative Aging

Experimental Research of Thermal-Oxidative Aging on the Mechanics of Aero-NBR

2014 ◽  
Vol 42 (3) ◽  
pp. 20130001 ◽  
Author(s):  
Y. Wu ◽  
D. Wang ◽  
W. Zhang ◽  
J. Zhang
Keyword(s):  
Experimental Research ◽  
Oxidative Aging ◽  
Thermal Oxidative Aging

Effect of Thermal-Oxidative Aging on the Mechanical Properties of Carbon Fiber Reinforced Bis-Maleimide Composites

2010 ◽  
Vol 152-153 ◽  
pp. 829-833 ◽  
Author(s):  
Xin Ying Lv ◽  
Rong Guo Wang ◽  
Wen Bo Liu ◽  
Long Jiang
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Aging Time ◽  
Testing Temperature ◽  
Fiber Reinforced ◽  
Oxidative Aging ◽  
Fiber Reinforced Polymer Composites ◽  
Carbon Fiber Reinforced ◽  
Thermal Oxidative Aging

Bis-maleimide (BMI) resins are widely applied in carbon fiber reinforced polymer composites in aerospace fields, for their excellent thermal and mechanical properties. The effects of thermo-oxidative aging on mechanical properties of carbon fiber reinforced BMI composites were investigated by SEM with the combination of flexural strength test and inter-laminar shear strength (ILSS) test. The results indicated that the thermal-oxidative aging had some effects on mechanical properties of carbon fiber/BMI composites; however the testing temperature or service temperature had much more effects than aging time. With aging time increased, the flexural strength at 150 oC and the ILSS at 25 oC slightly increased, while the ILSS at 150 oC decreased gradually. Both test results of mechanical properties and fracture models of damaged flexural specimens by SEM indicated that the matrix resin in the composites showed some viscoelastic behaviors that resulted in the remarkable dependence of mechanical properties of the composites on temperature. Therefore, the carbon fiber reinforced BMI composites had lower flexural strength and ILSS at 150 oC than that at 25 oC.

Investigation of physical properties and morphology of compatibilized EPDM/EVA blends

2017 ◽  
Vol 31 (3) ◽  
pp. 376-391 ◽  
Author(s):  
Aman I Khalaf ◽  
Azza A Ward ◽  
Nehad N Rozik
Keyword(s):  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Elongation At Break ◽  
Oxidative Aging ◽  
Itaconic Anhydride ◽  
Aging Resistance ◽  
Before And After ◽  
Time Periods ◽  
Poly Ethylene ◽  
Thermal Oxidative Aging

The main aim is to investigate the effect of adding of 5% hydrolyzed poly (ethylene-co-vinyl acetate) (EVAOH), itaconic anhydride (naturally obtained during fermentation of sugars (It.anhydride)), and mercapto-modified ethylene-co-vinyl acetate (EVASH) as compatibilizers on the mechanical properties before and after thermal oxidative aging at 90°C for different time periods up to 7 days, electrical properties, and morphology of ethylene propylene diene monomer/ethylene vinyl acetate (EPDM/EVA) blends of different compositions (75/25, 60/40, 50/50, and 25/75, respectively). Stress at yield, tensile strength, and elongation at break of EPDM/EVA were improved markedly by the addition of 5% compatibilizers (EVAOH, It.anhydride, and EVASH). The micrographs of fractured surfaces obtained from the scanning electron microscope demonstrated further the enhancement of compatibility between EPDM and EVA by the addition of reactive compatibilizers. Further, the blends permittivity ε′ and dielectric loss ε″ have been measured at specific temperatures. The dielectric properties revealed that It.anhydride and EVASH/EPDM/EVA compositions are promising materials for insulation purposes. Finally, aging resistance was improved by the use of compatibilizers.

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