Properties of Hard Rubber. XXI. Influence of Vulcanization Temperature

1947 ◽  
Vol 20 (4) ◽  
pp. 1039-1053
Author(s):  
H. F. Church ◽  
H. A. Daynes
Keyword(s):  
Impact Strength ◽  
Power Factor ◽  
Present Report ◽  
Small Samples ◽  
Test Results ◽  
Plastic Yield ◽  
Different Temperatures ◽  
Similar Materials ◽  
The Times ◽  
The Impact

Abstract In previous reports the properties of hard rubber made from rubber and sulfur were studied with particular reference to the effects of varying the rubber-sulfur ratio and vulcanization time. In the present report, a continuation of this investigation, the influence of temperature of vulcanization of similar materials is studied. Materials having rubber-sulfur ratios of 65/35 and 70/30 were vulcanized in a press at three different temperatures, namely, 165°, 155°, and 135° C, the times of vulcanization employed being estimated to be equivalent to 5 hours at 155° C. As a check on the estimate of the equivalent times, small samples of the same materials were vulcanized for various shorter and longer periods and were tested for plastic yield temperature and percentage of free sulfur. The main materials were tested for the following properties by the methods described in the previous report : Combination of sulfur, density, cross-breaking strength and elongation, impact strength, plastic-yield temperature, permittivity and power factor at audio and radio frequencies, and surface discoloration in sunlight. Certain anomalous figures were obtained in the impact test results which were thought to be due to the necessity of carrying out the longer vulcanization processes in stages. Arrangements were made accordingly to conduct the vulcanization continuously in such cases. This procedure brought about a considerable improvement in the results. These results confirmed the conclusion reached in the previous report that impact strength is very sensitive to untraced variables in manufacture. The results of the permittivity and power factor tests are discussed at some length, since they afford useful information on a number of other variables, principally rubber-sulfur ratio, frequency, and temperature of test. In a general discussion of the results, the choice of the best vulcanization temperature is examined. It is concluded that the selection of the best temperature involves compromise between opposing tendencies in the different properties.

A Four Novel Energy Pattern Factor Method for Computation of Weibull Parameter in Impact Strength Reliability of Fibre-Reinforced Concrete

2018 ◽  
Vol 7 (3.12) ◽  
pp. 272
Author(s):  
Gayathri R ◽  
Murali. G ◽  
Parthiban Kathirvel ◽  
Haridharan M.K ◽  
Karthikeyan. K
Keyword(s):  
Reinforced Concrete ◽  
Impact Strength ◽  
Shape Parameter ◽  
Failure Strength ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Weibull Parameter ◽  
Impact Failure ◽  
Novel Method ◽  
The Impact

Impact strength data is a noteworthy factor for designing airport pavements, civilian and military structures etc and it is ought to be modelled precisely. In order to achieve an appropriate modelling data, it is important to select a suitable estimation method. One such commonly used statistical tool is the two parameter Weibull distribution for modelling impact failure strength accurately besides the variations in test results. This study statistically commandsthe variations in the impact failure strength (number of blows to induce failure) of fibre reinforced concrete (FRC) subjected to drop hammer test. Subsequently, a four-different novel method for the computation of Weibull parameter (Shape parameter) based on the earlier researchers test results has been proposed. The accuracy of the proposed four novel method is demonstrated by comparing with power density method and verified with goodness of fit test. Finally, the impact failure strength of FRC is offered in terms of reliability. The proposed four NEPFM is very suitable and efficient to compute the shape parameter in impact failure strength applications. 

A Four Novel Energy Pattern Factor Method for Computation of Weibull Parameter in Impact Strength Reliability of Fibre-Reinforced Concrete

2018 ◽  
Vol 7 (3.12) ◽  
pp. 272
Author(s):  
Gayathri R ◽  
Murali. G ◽  
Parthiban Kathirvel ◽  
Haridharan M.K ◽  
Karthikeyan. K
Keyword(s):  
Reinforced Concrete ◽  
Impact Strength ◽  
Shape Parameter ◽  
Failure Strength ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Weibull Parameter ◽  
Impact Failure ◽  
Novel Method ◽  
The Impact

Impact strength data is a noteworthy factor for designing airport pavements, civilian and military structures etc and it is ought to be modelled precisely. In order to achieve an appropriate modelling data, it is important to select a suitable estimation method. One such commonly used statistical tool is the two parameter Weibull distribution for modelling impact failure strength accurately besides the variations in test results. This study statistically commandsthe variations in the impact failure strength (number of blows to induce failure) of fibre reinforced concrete (FRC) subjected to drop hammer test. Subsequently, a four-different novel method for the computation of Weibull parameter (Shape parameter) based on the earlier researchers test results has been proposed. The accuracy of the proposed four novel method is demonstrated by comparing with power density method and verified with goodness of fit test. Finally, the impact failure strength of FRC is offered in terms of reliability. The proposed four NEPFM is very suitable and efficient to compute the shape parameter in impact failure strength applications. 

scholarly journals ADDITION OF RICE HUSK NANOCELLULOSE TO THE IMPACT STRENGTH OF RESIN BASE HEAT CURED

2021 ◽  
Vol 4 (3) ◽  
pp. 119
Author(s):  
Muhammad Aditya Ramadhan Hasran ◽  
Dian Noviyanti Agus Imam ◽  
Bambang Sunendar
Keyword(s):  
Impact Strength ◽  
Mechanical Strength ◽  
Rice Husk ◽  
Acrylic Resin ◽  
Control Group ◽  
P Value ◽  
Test Results ◽  
Nano Cellulose ◽  
Reinforcing Material ◽  
The Impact

Background: One of the materials for denture bases is heat-cured acrylic resin (PMMA). This material still lacks impact strength as a mechanical strength property. The addition of reinforcing material is known to increase the mechanical strength of PMMA. One of the reinforcing materials added to PMMA is nano cellulose from rice husks, one of the wastes from agricultural products. Purpose: This study aims to determine rice husk nano cellulose's addition to the PMMA denture base's impact strength. Method:  The research sample consisted of six groups, each group consisting of 8 samples selected by simple random. The PI, P2, P3, P4, P5, and K groups were PMMA with 1%, 2%, 3%, 4%, 5% nano cellulose, and without nano cellulose. Result: Mean impact strength test results were 41.50 x 10-3 ± 3.891 J / mm2 for P1, 44.13 x 10-3 ± 3,980 J / mm2 for P2, 45.63 x 10-3 ± 4,438 J / mm2 for P3, 46.87 x 10-3 ± 4,824 J / mm2 for P4, 49.12 x 10-3 ± 4.016 J / mm2 for P5 and 36.25 x 10-3 ± 1.982 J / mm2 for K. One way Anova test results with p-value of 0.000 indicates differences in the six groups (p<0.05). Conclusion: This study concludes that the impact strength value of PMMA with the addition of rice husk nano cellulose has increased compared to the control group without the addition of rice husk nano cellulose.

EFFECT OF ANTIBIOTICS AUGMENTATION AND STORAGE CONDITION ON IMPACT RESISTANCE OF ORTHOPEDIC BONE CEMENT

2017 ◽  
Vol 17 (01) ◽  
pp. 1750019
Author(s):  
MARYAM KALANTARI ◽  
ATA HASHEMI
Keyword(s):  
Impact Strength ◽  
Bone Cement ◽  
Storage Temperature ◽  
Impact Resistance ◽  
Storage Condition ◽  
Four Point Bending ◽  
Pmma Bone Cement ◽  
Different Temperatures ◽  
Aging Conditions ◽  
The Impact

Antibiotic-impregnated poly(methyl methacrylate) (PMMA) bone cement has been successfully used to treat infected joint arthroplasties and surgeons have advocated the use of antibiotic-treated bone cement to prevent possible infections in joint replacement surgeries. However, there is a concern that this addition may adversely affect the mechanical properties of the bone cement. In most cases, the addition of antibiotics to bone cement has been reported to lower its mechanical strength. The uniaxial, biaxial and three/four point bending tests of antibiotic-impregnated bone cement have been extensively performed and well documented. However, only a few documents have focused on the impact strength of bone cement. The present study reports the impact tests of control and antibiotic loaded bone cements at different temperatures and aging conditions. According to the results, the addition of gentamicin or vancomycin significantly reduced the samples' impact strength. Moreover, the samples aged in saline at 23[Formula: see text]C were more resistant than the samples aged in air at 23[Formula: see text]C. Furthermore, raising the storage temperature from 23[Formula: see text]C to 37[Formula: see text]C significantly lowered the bone cement's impact strength in both control and antibiotic loaded samples.

Properties of Hard Rubber. XI. Experiments on Aging

1944 ◽  
Vol 17 (4) ◽  
pp. 913-922 ◽  
Author(s):  
H. F. Church ◽  
H. A. Daynes
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Short Distance ◽  
Prolonged Exposure ◽  
Breaking Strength ◽  
The Other ◽  
Rapid Loss ◽  
Test Pieces ◽  
Plastic Yield ◽  
The Impact

Abstract Tests have been carried out to find how the mechanical properties of hard rubber change with age. On prolonged exposure of the whole specimen to air at 70° C, the impact strength of notched and unnotched test-pieces may fall by 50 per cent or more. On the other hand, the plastic yield temperature increases appreciably with 200 days' exposure. The conditions affecting the improvement in such an important property are worthy of further serious study. When certain faces of the specimen are protected from the air, the rapid loss of impact strength does not take place, and cross-breaking strength may remain unimpaired for as long as 200 days. The deterioration on aging appears to be confined within a very short distance of the surface, the bulk of the material retaining its full strength for very long periods. The retention of strength when certain faces are protected may have an important bearing on questions of design. Examination of old samples of hard rubber shows that the mechanical properties remain good under ordinary conditions of storage for periods of 20–30 years, but that weakness may be caused at surfaces which are severely exposed to sunlight.

scholarly journals The Effect Of Heating Acrylic Resin Of Various Types With Different Temperatures On Impact Strength

2021 ◽  
Vol 12 (2) ◽  
pp. 141-148
Author(s):  
Didik Marsigid
Keyword(s):  
Impact Strength ◽  
Base Material ◽  
Acrylic Resin ◽  
Type A ◽  
Transverse Resistance ◽  
Different Temperatures ◽  
Experimental Laboratory ◽  
The Impact ◽  
Unstable Temperature

Resin polymerization which is affected by unstable temperature causes the resin to break easily. The strength of the base material is affected by the forces acting in the mouth, such as transverse forces, other resistance or fatigue, and flexibility. Fracture of denture caused by masticatory loads and is affected by forces acting in the mouth, including transverse, resistance or fatigue, and flexural forces. Experimental Laboratory total of 72 samples consisting of 18 samples of  type A, B and C cured at normal temperature, 100oC, 200oC, and 300oC. Types A, B and C have the effect of heating with the addition of temperature on the impact strength of acrylic resin, because the value of sig = 0.001 < 0.05, so H0 is rejected. An effect with the addition of temperature on the impact strength of the resin types A, B and C, because sig = 0.001 < 0.05, so H0 is rejected, which means that the average results are significantly different due to differences in temperature.

scholarly journals Using the Plate-Creep test to determine the impact strength properties of concrete

2021 ◽  
Author(s):  
Murat Gökçe ◽  
Keyword(s):  
Impact Strength ◽  
Creep Test ◽  
Impact Test ◽  
Impact Resistance ◽  
Strength Properties ◽  
Test Results ◽  
Test Device ◽  
Concrete Mixtures ◽  
Repetitive Impact ◽  
The Impact

The paper aims to design a concrete against repetitive impact and abrasion resistance. Macro/micro steel fibers and two types of crushed stone based on limestone and corundum as aggregate were used in concrete mixtures. Impact test device has been modified, designed and used for impact strength testing of concrete. The usability of the plate creep test in determining the impact strength of concrete was also investigated. According to the test results, a high correlation was found between the abrasion, impact resistance tests and the creep test.

Properties of Hard Rubber. XXII. Development of Proof Impact Test for Insulating Materials. Comparison of Pendulum and Falling-Weight Machines

1947 ◽  
Vol 20 (4) ◽  
pp. 1054-1076
Author(s):  
E. H. Dock ◽  
J. R. Scott
Keyword(s):  
Impact Strength ◽  
Excess Energy ◽  
Test Results ◽  
Root Radius ◽  
Advantages And Disadvantages ◽  
Test Pieces ◽  
Pendulum Test ◽  
Falling Weight ◽  
The Impact ◽  
Two Machines

Abstract A comparison has been made of impact tests by the pendulum machine (Izod) and by the falling-weight machine (Izod and Charpy), using fabric board, paper board, molded resin (Bakelite), and ebonite, each in four types of test-pieces; unnotched, saw-cut notch, V-notch with 1 mm. root radius, and V-notch with 0.5 mm. root radius. The effect of notching on impact strength varies from one material to another, and may alter their order of merit. Saw-cut and V-notches with the same root radius nearly always give about the same results, and reducing the root radius usually (but not always) reduces the impact strength. The pendulum machine always gives higher results than the falling weight-machine in Izod tests, and the ratio varies with the material, though not sufficiently to alter the order of merit. Under the conditions used in the present tests with the falling-weight machine, Charpy tests (70 mm. between supports) nearly always give higher values than Izod tests (22 mm. striking distance), but both arrange the materials in the same order of merit. Standard errors are worked out for the pendulum test results; V-notched specimens appear to give, if anything, the best accuracy. The sources of variability in test results, and hence of errors in the final value, are discussed in an attempt to compare the accuracies of the two machines. Although an exact comparison could not be made, there appears to be no great difference between the two machines as regards the accuracy of the result obtained with a given number of test-pieces. The four types of test-piece differ very little, on the whole, in this respect. With the falling-weight machine, the Charpy test appears to give rather better accuracy than the Izod test. There is no definite evidence that the amount of excess energy in the pendulum test influences the result, except perhaps with Bakelite. The variability of all four materials tested is such that a maximum excess energy limit of 25 per cent cannot be adhered to without excluding either the weakest or the strongest specimens and so obtaining a false mean. In Izod tests on the pendulum machine a 20 mm. striking distance gives higher values for fabric board than a 35 mm. striking distance; the former has the advantage that no incomplete breaks occur, as happens with the longer striking distance. Attention is drawn to certain advantages and disadvantages of the two types of machine, and to the necessity for defining a “break” in the case of laminated materials, where cracks or incomplete breaks are frequent.

scholarly journals The Influence of Selected Test Conditions on the Impact Strength of Adhesively Bonded Connections

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1320 ◽  
Author(s):  
Jan Godzimirski ◽  
Andrzej Komorek
Keyword(s):  
Aluminum Alloy ◽  
Impact Strength ◽  
Experimental Research ◽  
Test Results ◽  
Adhesively Bonded ◽  
Elastic Deformations ◽  
Epoxy Adhesives ◽  
Test Conditions ◽  
Adhesive Connections ◽  
The Impact

The conditions of adhesive connections testing can significantly affect the recorded findings. The standards, under which the investigations are conducted, do not take into account numerous factors that can greatly influence the outcome of the tests. Moreover, the research parameters in the standards are not specified. It is not defined in what manner their change, or any failure to comply with the standards, will affect test results. This article presents the results of experimental research, completed with numerical simulations, designed to test to what extent the recorded impact strength of adhesive connections is affected by the stiffness of the test stand, and the speed and energy of the impactor. In the experimental research, the authors used block samples whose substrates were made of an aluminum alloy. The elements of the samples were bonded by means of three different epoxy adhesives. The models used in numerical calculations were built on the basis of the real dimensions of the specimens used in this experimental research. As a result of the performed tests and conducted calculations, it was found that the use of test stands of lesser stiffness resulted in an increased registered impact strength due to an increased energy value of elastic deformations.

scholarly journals Effect of High Temperatures on the Impact Strength of Concrete Based on Recycled Aggregate Made of Heat-Resistant Cullet

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 465 ◽  
Author(s):  
Aleksandra Powęzka ◽  
Jacek Szulej ◽  
Paweł Ogrodnik
Keyword(s):  
Compressive Strength ◽  
Impact Strength ◽  
Testing Procedure ◽  
Recycled Aggregate ◽  
Test Results ◽  
Heat Resistant ◽  
Temperature Impact ◽  
The Impact ◽  
Average Compressive Strength ◽  
By Products

The article presents results obtained during testing of concrete based on CEM I 42.5R Portland cement, fine and coarse aggregate, glass, volatile ash, and superplastifier. The concrete mixture was modified using filler consisting of bromosilicate heat resistant cullet. Recycled aggregate was added to the batch. Samples for the need of testing were produced as (100 × 100 × 100) mm cubes. Before commencing proper tests, samples have been heated within the temperature range of 20–800 °C. Tests carried out during the proper testing procedure included tests of compressive strength, elevated temperature, impact strength, as well as macroscopic tests of the contact area. The obtained test results have provided proof of there being a possibility of producing special concrete, modified by products obtained from heat resistant cullet. This type of is generally characterized by satisfactory performance parameters. The average compressive strength for concrete modified by a 10% of heat resistant cullet was determined as 43.6 MPa and 48.3 MPa respectively after 28 and 180 days of curing.

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