Study on Thermal Oxidative Aging of Nitrile Rubber

2013 ◽  
Vol 299 ◽  
pp. 199-202 ◽  
Author(s):  
Xiao Gang Li ◽  
Yu Long Zhang ◽  
Ming Yuan Yang
Keyword(s):  
Tensile Strength ◽  
Accelerated Aging ◽  
Tensile Fracture ◽  
Oxidative Aging ◽  
Polymer Fracture ◽  
Hot Air ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Fracture Appearance ◽  
Thermal Oxidative Aging

This paper studies the changing regularity of hardness and tensile strength, through accelerated aging test of NBR in hot air. The tensile fracture appearance of test samples aging for different time is observed. The results indicate that NBR’s hardness increases firstly and then decreases and finally increases again, tensile strength presents escalating trend and the change of tensile fracture corresponds with polymer fracture mechanism of elastic material.

Aging of Rubber in the Oxygen Bomb at Room Temperature

1943 ◽  
Vol 16 (4) ◽  
pp. 924-925
Author(s):  
J. R. Scott
Keyword(s):  
Tensile Strength ◽  
Oxygen Concentration ◽  
Room Temperature ◽  
Accelerated Aging ◽  
Natural Aging ◽  
Tensile Tests ◽  
Oxygen Bomb ◽  
Vulcanized Rubber ◽  
Accelerated Aging Test ◽  
Aging Test

Abstract The work described below was carried out as a first step in determining whether an oxygen-bomb test at room temperature could be used as an accelerated aging test for unvulcanized rubber compositions, e.g., as used on surgical and adhesive plasters and for combining shoe fabrics, because a high-temperature test is unsatisfactory in such cases, owing to the melting of the compositions. The only infallible way of assessing the value of an accelerated test for such compositions is by comparison with natural aging, but as this is a very lengthy process and as the deterioration is difficult to measure quantitatively, it was decided to make preliminary tests on the effect of high oxygen concentration at room temperature by using vulcanized rubber. Although the results proved to be negative so far as the original purpose of the work was concerned, it is considered of interest to place them on record in view of the prominence given in some papers on aging to the relationship between oxygen concentration and rate of oxidation and deterioration of rubber. A mix composed of rubber 100, sulfur 3, zinc oxide 5, stearic acid 1, and diphenylguanidine 0.75, was vulcanized for 30 minutes at 153° C. Tensile tests, using standard ring-specimens and the Schopper machine, were made on unaged specimens and on specimens that had been aged (1) in an oxygen bomb at 300 lb. per sq. in. oxygen pressure and at room temperature (about 10° C), (2) in a Geer oven at 70° C. Four rings were used for each test, the tensile strength and breaking elongation figures quoted being the average for the two rings giving the highest tensile strength, and the figures for the elongations at constant loads the average of all four rings.

Prediction of Lifetime of Nylon 66 as an Airbag Material

2011 ◽  
Vol 332-334 ◽  
pp. 1709-1713 ◽  
Author(s):  
Ge Chen ◽  
Jia Lu Li
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Service Life ◽  
Accelerated Aging ◽  
Test Results ◽  
Nylon 66 ◽  
Oxidative Aging ◽  
Thermal Oxidative Aging ◽  
Aging Parameter

Through the earlier accelerated aging tests (oven aging) of Nylon 66 yarns used in automobile airbags at the temperatures ranging from 60°C to 150°C, we have established a dynamics equation of tensile strength and aging time, and predicted the storage lifetime of this material in 25°C based on Arrhenius methodology and extrapolation method. Besides, the activation energy and thermal-oxidative aging parameter of Nylon 66 have been worked out from the test results. The study has showed that Nylon 66 airbag material has great thermal stability at high temperatures, and its storage lifetime under normal temperature is 4 times of its expected lifetime by design. The prediction results can be referenced for planning the service life of SRS or selecting airbag fabrics.

scholarly journals Genetic diversity for physiological quality of seeds from corn (Zea mays L.) intervarietal crossbreeds

2013 ◽  
Vol 35 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Daniele Nerling ◽  
Cileide Maria Medeiros Coelho ◽  
Rubens Onofre Nodari
Keyword(s):  
Genetic Diversity ◽  
Zea Mays L ◽  
Accelerated Aging ◽  
Genetic Contribution ◽  
Percentage Germination ◽  
Canonical Variables ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Physiological Quality

The physiological quality is based on the genotype and may be accompanied since the first stages of selection through the study of genetic diversity. The purpose of this study was to evaluate the parental genetic contribution in the seed physiological quality in corn intervarietal crossbreeds. The intervarietal crossbreeds were performed using landraces genotypes, open pollinated varieties and commercial hybrids. The seeds obtained from the crossbreed, their equivalents and parentals were evaluated regarding their water percentage, germination, germination speed rate, accelerated aging, field emergence and electrical conductivity. The seeds obtained in the crossbreed are viable and vivid with heterosis when compared with the parentals. The accelerated aging test was more effective for selecting the strongest genotypes. The canonical variables were useful to group the genotypes that presented similar physiological characteristics. The genotypes MPA 01 x Pixurum 05, MPA 01 x AS1565, MPA 01 x SJC5886, SJC5886 x Pixurum 05 and Fundacep 35 x SCS 154 Fortuna were the best crossbreeds regarding the production of better physiological quality seeds.

scholarly journals Accelerated aging test in amaranth (Amaranthus cruentus L.) seeds

2018 ◽  
Vol 12 (03) ◽  
pp. 444-448
Author(s):  
Andréa Bicca Noguez Martins ◽  
◽  
Caroline Jácome Costa ◽  
Fernanda da Motta Xavier ◽  
André Pich Brunes ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Amaranthus Cruentus ◽  
Accelerated Aging Test ◽  
Aging Test

scholarly journals Electrical conductivity and accelerated aging in amaranth (Amaranthus crueentus L.) seeds

2018 ◽  
Vol 40 (1) ◽  
pp. 44-51
Author(s):  
Thaís D’Avila Rosa ◽  
Ariele Paula Nadal ◽  
Henrique Roberto Maldaner ◽  
Vanessa Nogueira Soares ◽  
Gizele Ingrid Gadotti ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Accelerated Aging ◽  
Water Volume ◽  
Amaranthus Cruentus ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Immersion Period ◽  
Amaranth Seed

Abstract: The objective of this study was to determine adequate conditions of water volume, seed quantity and immersion period to perform the electrical conductivity test, and to analyze the parameters of the accelerated aging test and its correlation with the the physiological potential of amaranth seeds. Five lots of amaranth seeds (Amaranthus cruentus), cultivar BRS Alegria, were used. The initial evaluation of the quality of these lots comprehended the following tests: water content, germination, first germination count, accelerated aging (traditional method, and modified versions, using unsaturated and saturated saline solution for the periods of 24, 48 and 72 h), electrical conductivity in different periods (2, 4, 6, 8 and 24 h), different quantities of water (25, 50 and 75 mL), different seed quantities (100 and 150), and field emergence. It could be concluded that the accelerated aging test at 41 °C, for 72 h, using unsaturated NaCl solution was efficient in the classification of amaranth seed lots in levels of vigor. The electrical conductivity test performed for 8 hours with 25 mL of water and 100 seeds was efficient in the classification of amaranth seeds as to their physiological potential.

scholarly journals INTEMPERISMO ARTIFICIAL DE QUATRO REVESTIMENTOS APLICADOS EM MADEIRAS DE DUAS ESPÉCIES FLORESTAIS

Nativa ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 313 ◽  
Author(s):  
Aline Krolow Soares ◽  
Roberto Lessa Pereira ◽  
Pedro Henrique Gonzalez de Cademartori ◽  
Henrique Weber Dalla Costa ◽  
Darci Alberto Gatto
Keyword(s):  
Morphological Changes ◽  
Eucalyptus Grandis ◽  
Accelerated Aging ◽  
Surface Wettability ◽  
Forest Species ◽  
Artificial Weathering ◽  
Color Changes ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Weathering Resistance

O presente estudo teve como objetivo investigar a resistência ao intemperismo artificial de quatro revestimentos aplicados nas madeiras de duas espécies florestais. Para tal, foram utilizadas seis árvores de Eucalyptus grandis e três árvores de Tetrorchidium rubrivenium as quais foram desdobradas para confecção de 50 amostras para cada espécie, com dimensões de 5,0x7,0x1,0cm (largura, comprimento e espessura, respectivamente). A superfície das madeiras foi revestida com quatro acabamentos: polistein, verniz marítimo, tinta branca base óleo e tinta branca base água. As amostras sem revestimento e revestidas foram submetidas ao ensaio de envelhecimento acelerado durante 480 horas. A resistência ao intemperismo artificial foi avaliada por meio das modificações colorimétricas e morfológicas ao longo da exposição das madeiras e em função da molhabilidade superficial. Os principais resultados mostraram que a superfície das madeiras  tendeu a tons opacos após exposição de 480 horas. Foi observado que os revestimentos não evitaram o aumento da molhabilidade superficial. Após todo o período de exposição, as madeiras não apresentaram modificações morfológicas tais como rachaduras e descascamento dos revestimentos, o que denota importante característica de proteção à madeira.Palavras-chave: Eucalyptus, canemaçu, modificação da superfície, envelhecimento acelerado, durabilidade da madeira. ARTIFICIAL WEATHERING OF FOUR COATINGS APPLIED ON WOODS OF TWO FOREST SPECIES ABSTRACT:The present study aimed to investigate the resistance to artificial weathering of four coatings applied on wood from two forest species. Six trees of Eucalyptus grandis and three trees of Tetrorchidium rubrivenium were cut to produce 50 wood samples for each species with dimensions of 5.0x7.0x1.0 cm (width, length and thickness, respectively). Wood surface was coated with four finishing products: polistein, marine varnish, oil-based white paint and water-based white paint. The uncoated and coated wood samples were subjected to accelerated aging test for 480h. The artificial weathering resistance was evaluated by color changes and surface wettability. The main results showed the coated woods tend to opaque tones after the exposure for 480h. The coatings did not avoid the increase of the surface wettability. After the exposure, both woods did not present morphological changes, such as cracks and peeling into the coatings, which represent relevant characteristics for wood protection.Keywords: Eucalyptus, canemaçu, surface modification, accelerated aging, wood durability. DOI:

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