Influence of Curing Agents on Rubber-to-Textile and Rubber-to-Steel Cord Adhesion

1973 ◽  
Vol 46 (4) ◽  
pp. 981-998 ◽  
Author(s):  
K.-D. Albrecht
Keyword(s):  
The Other ◽  
Complete Wetting ◽  
Bonding Agents ◽  
Pull Out ◽  
Steel Cord ◽  
Sulfur Level ◽  
Curing Agents ◽  
Reinforcing Material ◽  
Heat History ◽  
Pull Out Strength

Abstract The results presented in this paper show that the dosage of sulfur greatly influences rubber-to-textile and rubber-to-steel cord adhesion. As far as rubber-to-textile adhesion is concerned, the pull-out strength is reduced when the sulfur level falls below 2 phr, the extent of the reduction depending on the type of fiber and the bonding process. With steel cord the lower limit for sulfur is as high as 3 phr. This is discouraging because it shows that the use of efficient and semi-efficient vulcanization in the manufacture of goods reinforced with fabrics or steel cord is, to say the least, highly problematical. On the other hand, it is often desirable to reduce the proportion of sulfur in order, for instance, to increase resistance to aging and reversion and to reduce compression set and heat build-up. The choice of accelerators also has an important influence on adhesion. A sufficiently long scorch time is required to allow complete wetting of the reinforcing material by the rubber compound. If curing starts before complete wetting of the textile or steel cord has occurred, adhesion cannot be built up. For example, unsatisfactory or no rubber-to-textile and rubber-to-steel cord adhesion is obtained, when ultra-accelerators are used. As the scorch time increases, adhesion improves. Best results are obtained with sulfenamides, but sulfenamides showing increasing scorch time give no improvement in rubber-to-textile bonding. However, DCBS gave much better results for rubber-to-steel cord adhesion than the other sulfenamides and thus appears particularly suitable. Although the results given by the other sulfenamides can be somewhat improved by the addition of a retarder, pull-out strength values do not reach those given by DCBS. Any decrease of scorch time of a compound deteriorates adhesion whether scorch time is reduced by compounding ingredients or by heat history imposed by processing. MBI, used as an antioxidant, which reduces scorch time drastically, causes complete loss of rubber-to-steel cord adhesion and also impairs rubber-to-textile adhesion. Most of the antioxidants, however, have a beneficial effect on mbber-to-steel cord adhesion. For zinc-plated steel cord antioxidants of the amine type give results inferior to those of the phenolic type. To obtain optimal rubber-to-textile and rubber-to-steel cord adhesion the compounder primarily has to consider the efficacy of the bonding agents but in addition he has to take into account the effects which may be exerted by compounding ingredients and processing conditions.

scholarly journals Experimental Study of Post Installed Rebar Anchor Systems for Concrete Structure

2020 ◽  
Vol 16 (2) ◽  
pp. 308-319
Author(s):  
Haidar H. Haidar ◽  
Faten I. Mussa ◽  
Abbas O. Dawood ◽  
Ahmed A. Ghazi ◽  
Rassel A. Gabbar
Keyword(s):  
Experimental Study ◽  
Bond Strength ◽  
Hole Diameter ◽  
The Other ◽  
Bonding Agents ◽  
Pull Out ◽  
Varied Chemical ◽  
Anchor Systems ◽  
Cylindrical Samples ◽  
Concrete Interface

AbstractThis study investigated the effectiveness of several types of adhesives used in post-installed rebar connections as a bonding agent between steel reinforcement bars and old concrete under pull out test. The experimental samples were; cylindrical samples of (150 mm dia. × 300 mm high) with anchors rebar of varying diameter (12 and 16 mm), different embedded length (100 and 150) mm with different holes’ diameters. The strategy of control were cast-in-place rebar concrete specimens while other samples are post-installed rebar concrete specimens of varied chemical adhesives as bonding agents, namely KUT EPOXY ANCHOR ‘NS’ and SIKAFLOOR169. The output showed that the different adhesives yielded closed pull-out load values. It is found that the pull-out capacity (bond strength) is increased by increasing the embedded length, the diameter of the rebar and slightly with the diameter of the hole. In addition, the failure mode of post-installed rebar concrete was governed by the embedded length and the area of contact with the adhesives. On the other hand, the larger diameter of rebar favors splitting or failure of concrete due to higher strength in binder-rebar interface compare to the binder-concrete interface. The results showed that the pull-out load was increased by (26 % and 32 %) as the rebar diameter increased from 12 mm to 16 mm for KUT “NS” and SIKAFLOOR respectively. The hole diameter had slightly effect of the pull out load where the average of increment was only 6 %. Finally, the bonding strength is considerably depended on the embedded length and less affected by the type of epoxy.

A Study on Heat History of Organic Accelerators in Rubber Stock (BR Base)

1970 ◽  
Vol 43 (4) ◽  
pp. 799-828
Author(s):  
I. Imase
Keyword(s):  
The Other ◽  
Frictional Heat ◽  
Rubber Matrix ◽  
Rubber Compound ◽  
Incremental Effect ◽  
Rubber Compounds ◽  
History Of ◽  
Curing Agents ◽  
Heat History ◽  
Rubber Stock

Abstract Rubber with some exceptions must generally undergo such processes as mastication, mixing, warming-up, extrusion, spreading, calendering, etc. prior to vulcanization under heat to obtain cured articles. Consequently the rubber matrix receives a heat history caused by mechanical frictional heat or the heat which cannot be avoided during these processes. On the other hand, when an uncured rubber compound, ready for vulcanization, containing such curing agents as sulfur, such activators as zinc oxide, and organic accelerators is heated during the processes or during storage between individual processes, each incremental effect of heat is accumulated with time. It is a well-known fact that this accumulation of heat can lead to the trouble of scorching, etc. As a cause for the trouble, organic accelerators seem to play the most important role. A few reports have been published on the action of accelerators under heat, but, to my knowledge, no report is available on the behavior of accelerators in rubber stocks, namely, on the change of the properties of uncured rubber compounds and on its influence on the properties of vulcanizates. This paper shall report these problems, though it describes only the results of the tests carried out under specific conditions.

In vitro comparison of the holding power of 1.2 mm, 1.5 mm, and 2.0 mm orthopaedic screws in canine radii

2002 ◽  
Vol 15 (02) ◽  
pp. 78-84 ◽  
Author(s):  
R. B. Fitch ◽  
G. E. Pluhar ◽  
M. D. Salman ◽  
S. T. Kudnig
Keyword(s):  
The Other ◽  
Testing System ◽  
Screw Insertion ◽  
Holding Power ◽  
Pull Out ◽  
External Thread ◽  
Thread Diameter ◽  
Pull Out Strength ◽  
In Vitro Comparison

SummaryThe holding power of miniscrews in canine bone has not been investigated. This report compares the holding power of four different miniscrew types. The screw types tested were: 1.2 mm self-tapping screws, 1.5 mm tapped screws, 2.0 mm self-tapping screws and 2.0 mm tapped screws. They were randomly allocated to canine radius screw sites and screw pull-out strength was determined using a Mechanical Testing System (MIS) machine. The 1.2 mm self-tapping screw had a significantly weaker holding power than the other three screw types. Based upon these findings, the use of the 1.2 mm self-tapping screw cannot be recommended for use in thick cortical bone. There were not any significant differences in holding power of the other three screw types. The performance of the 1.5 mm tapped screws, versus the 2.0 mm tapped screws, was comparable and suggests that the 1.5 mm tapped screw can provide adequate holding power in miniscrew applications. The results were consistent with a linear relationship between the external thread diameter and the holding power.The hypothesis of this study is that these are not any significant differences in the holding power of different miniscrews. We hypothesized that the effects of tapping prior to screw insertion, or using miniscrews of greater external thread diameter, would not provide any increase in the holding power of the screw.

scholarly journals The effect of tissue culture on suture holding strength and degradation in canine tendon

2009 ◽  
Vol 34 (5) ◽  
pp. 643-650 ◽  
Author(s):  
H. OMAE ◽  
C. ZHAO ◽  
Y.-L. SUN ◽  
M. E. ZOBITZ ◽  
S. L. MORAN ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Tensile Load ◽  
Flexor Digitorum Profundus ◽  
Tendon Suture ◽  
Pull Out ◽  
Culture Model ◽  
Static Tensile ◽  
Tissue Culture Model ◽  
Flexor Digitorum ◽  
Pull Out Strength

The purpose of this study was to assess tendon metabolism and suture pull-out strength after simple tendon suture in a tissue culture model. One hundred and twelve flexor digitorum profundus tendons from 28 dogs were cultured for 7, 14, or 21 days with or without a static tensile load. In both groups increased levels of matrix metalloproteinase (MMP) mRNA was noted. Suture pull-out strength did not decrease during tissue culture. While the presence of a static load had no effect on the pull-out strength, it did affect MMP mRNA expression. This tissue culture model could be useful in studying the effect of factors on the tendon-suture interface.

Investigation of the tensile performance and failure mechanism of carbon–aramid hybrid fibers/epoxy sandwich structure laminates using the UV-thermal synergetic curing mechanism: Experimentation and simulation

2018 ◽  
Vol 22 (8) ◽  
pp. 2582-2603
Author(s):  
Jiaojiao Xi ◽  
Xiaoyan Liu ◽  
Zhiqiang Yu
Keyword(s):  
Finite Element ◽  
Failure Mechanism ◽  
Sandwich Structure ◽  
Experimental Results ◽  
Tensile Failure ◽  
Hybrid Fibers ◽  
Pull Out ◽  
Tensile Performance ◽  
Hybrid Laminates ◽  
Curing Agents

The tensile failure mechanism of carbon–aramid hybrid fibers/epoxy sandwich structure laminates was investigated by using experimental and finite element methods. Double curing agents, triarylsulfonium hexafluoroantimonates and triethylene tetramine with a mass ratio of 4:15 were introduced into the laminates. Sandwich structure laminates, with different proportions of hybrid fibers, were cured by UV-initiated anion/cationic dual curing technique. The results showed that the synergetic curing effects of two curing agents were observed under UV irradiation, leading to the better curing of the system, which further plays a positive influence on the mechanical performance. The tensile properties and failure mechanism of the laminates depended on the stacking sequence and fiber volume fractions of the layer structures. The interplay hybrid laminates, containing three alternate plies with fiber contents of 67.7 vol%, presented the optimal tensile performance, and its tensile strength and modulus were 0.82 GPa and 22.09 GPa, respectively. The fracture morphologies revealed that pull-out and debonding of fibers were the main failure mechanism of hybrid laminates. The performance of sandwich structure laminates was determined by the load-carrying capacity of carbon fiber and load-transferring capacity of the aramid fiber and adhesive. The finite element model based on experiments was established to simulate the stress state and failure mechanism of sandwich laminates. The results demonstrated that the stress was better transferred into carbon fibers from the aramid fibers and adhesive, and the relative error rate of maximum stress from finite element analysis and experimental results was less than 5%, which were in reasonable agreement with the experimental results.

scholarly journals PULL-OUT STRENGTH OF STEEL RODS BONDED INTO MENGKULANG (TARRIETIA JAVANICA) GLULAM AT FIVE DIFFERENT ANGLES TO THE GRAIN

2018 ◽  
Vol 30 (1) ◽  
pp. 67-74
Author(s):  
Mohamad WNN ◽  
Suliman NH ◽  
Kamarudin MK ◽  
Mohd-Amin N ◽  
Hassan R
Keyword(s):  
Pull Out ◽  
Pull Out Strength
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