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Cut and chip resistance

Authors:
Radek Stocek at PRL Polymer Research Lab, Czechia, Zlin
Radek Stocek
  • PRL Polymer Research Lab, Czechia, Zlin
William Mars at Endurica, LLC
William Mars
  • Endurica, LLC
Christopher G Robertson at Polymer Technology Services LLC
Christopher G Robertson
  • Polymer Technology Services LLC
Reinhold Kipscholl at coesfeld GmbH & Co. KG
Reinhold Kipscholl
  • coesfeld GmbH & Co. KG
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tread compound candidates.
The CC phenomenon is complex, yet traditional CC test meth-
ods for the rubber laboratory employ simple, non-instrumented
devices where sample weight loss is the only measurement (refs.
1-4). This article describes a new laboratory instrument for char-
acterization of CC behavior which has several test conditions that
can be independently controlled. It measures multiple force and
displacement data channels during testing of rubber specimens.
The testing principle and typical results for model rubber com-
pounds that are typical of tire tread applications will be discussed.
In particular, the methodology which can predict actual CC rank-
ings for tires from laboratory testing of tread compounds will be
highlighted.
Experimental details
Polymers used in this study were natural rubber (NR; SMR CV
60) and high cis butadiene rubber (BR; Buna CB 24 from Ar-
lanxeo). The reinforcing filler was an N339 grade of carbon black
(CB). All other ingredients were rubber grade chemicals. The
rubber formulations are given in table 1.
Rubber compounds were prepared in two mixing stages. For
the first stage, all ingredients except CBS accelerator and sulfur
were mixed for five minutes in an internal mixer (SYD-2L from
Everplast, Taiwan) at 50 rpm with a chamber wall temperature of
80°C. The CBS and sulfur curatives were added in the second
mixing stage on a two-roll mill at a temperature of 60°C.
Curing properties were determined by a moving die rheometer
(MDR 3000 Basic, MonTech, Germany) according to ASTM
6204 at 160°C. Rubber specimens with an outer diameter of 55
mm and thickness of 13 mm (see geometry shown in figure 2)
were cured in a heated press (LaBEcon 300, Fontijne Presses,
Netherlands) at 160°C according to the curing time t90 + 1 minute
per 1 mm of the thickness (13 minutes total added for specimen
thickness of 13 mm).
Laboratory chip and cut testing was performed on the rubber
specimens using an instrumented chip and cut analyzer (ref. 5)
(ICCATM) manufactured by Coesfeld GmbH, Germany (figure
2), and distributed in the Americas by Endurica LLC, USA. The
Characterizing rubber's resistance against
chip and cut behavior
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Cutting and chipping of tread rubber is a significant concern for
tires that are used in off-road or poor road conditions, where the
tires are in contact with gravel, rocks and uneven road surfaces.
Some examples of cut and chip (CC) damage to tire treads are
illustrated in figure 1. Due to the usual difficulty in predicting CC
resistance of tire treads from laboratory testing of rubber com-
pounds, it is often necessary to resort to expensive development
programs involving iterative tire building and field testing of new
38 RUBBERWORLD.COM JANUARY 2018
Figure 2 - photograph of instrumented chip
and cut analyzer (ICCA) showing expanded
view of impacting device and sample (left)
and diagram of rubber sample geometry
with 55 mm outer diameter and 13 mm
thickness (right)
Ø 26
Ø 55
Figure 1 - examples of various extents of
chip and cut damage to the treads of: TBR/
heavy truck tires (a) and (b); OTR/
construction vehicle tire (c); and mud-
terrain light truck tire (d)
(a)
(b)
(c)
(d)
Table 1 - rubber formulations
NR
BR
CB (N339)
Zinc oxide
Stearic acid
IPPD(a)
CBS(b)
Sulfur
NR/BR 50CB
75
25
50
3
1
1.5
2.5
1.7
NR/BR 65CB
75
25
65
3
1
1.5
2.5
1.7
(a) N-isopropyl-N’-phenyl-p-phenylenediamine
(b) N-cyclohexyl-2-benzothiazole sulfonamide
ed rotation speed and striking the sample with a stainless steel
impactor at a given frequency. The impact is produced using a
pneumatic cylinder, where the impact normal force, frequency
and contact (sliding) time with the rubber surface can all be sepa-
rately controlled. A schematic of the impacting device is shown in
figure 3, the impactor geometry is described in figure 4, and an
example of the data generated for each impact event is presented
in figure 5. The types of parameter inputs and outputs, along with
their ranges, are summarized in table 2, which emphasizes the
highly instrumented and flexible nature of the testing equipment.
One key characterization factor that is evaluated from the
multi-channel data acquisition is the chip and cut propensity, P.
The parameter P is determined from integrating the fluctuations in
friction force, related to roughness of the damaged surface, over a
number of impact cycles. The P value of tread compounds was
proven to be a very good predictor of actual tire cut and chip field
test results for a variety of agricultural tires, truck and bus radial
(TBR) tires, and light truck tires. The details cannot be shared due
to confidentiality considerations with major tire manufacturers.
The cut and chip behavior as a function of number of impact
ICCA equipment and test-
ing approach will be fur-
ther described in the next
section. Samples were
tested at a rotation speed
of 150 rpm, normal force
of 125 N, impact frequen-
cy of 5 Hz, and sliding
time of 30 ms for a varied
number of cycles.
Results and discussion
The principle of measure-
ment for the instrumented
chip and cut analyzer in-
volves rotating the round
rubber sample at a select-
FOLLOW US ON TWITTER @rubberworld 39
Figure 3 - schematic of ICCA measuring
principle, with: pneumatic actuator (1); two-
axis load cell (2); holder plus impactor (3);
and round rubber test sample (4)
Ff
Fn
ai
Z
123 4
Figure 5 - general graph showing multi-
channel data collection for one impact
loading cycle of ICCA measurement
Time of sliding, ts
Time
Normal force, fn
Force
Normal force
Friction force
Table 2 - list of parameters for the instrumented chip and cut analyzer
(ICCA)
Parameter
Rotation speed, Ȧ
Impact frequency, f
Number of impact cycles, n
Time of sliding, ts
Normal force, Fn
Friction force, Ff
Resulting force, Fc
Depth of indentation, ai
Friction distance, af
Normal energy, En
Friction energy, Ef
Friction coefficient, cf
Chip and cut propensity, P
Range
100 to 1,500
0 to 10
0 to undefined
20 to permanent
0 to 500
0 to 900
Calculated
0 to 20
Measured
Calculated
Calculated
Calculated
Calculated
Unit
rpm
Hz
-
ms
N
N
N
mm
mm
J
J
-
N/cycle
Defined
¥
¥
¥
¥
¥
Parameter type
Measured
¥
¥
¥
¥
¥
¥
¥
¥
Controlled
¥
¥
¥
¥
¥
Calculated
¥
¥
¥
¥
¥
Figure 4 - geometry of the stainless steel
impactor tool; the width of the impactor is
6.35 mm,which strikes the middle of the
13 mm thick rubber sample
Ra 0.8
Ra 0.8
R5
R2.5
Ra 0.8
60°
9.61
R0.8
16.55
R1
Ra 0.8
19.05
6.35
cycles was compared for two blend compounds: NR/BR 50CB
and NR/BR 65CB (see formulations in table 1). The results are
presented in figures 6 and 7. The slope of the P versus n data
shows very distinct values for the two materials. A greater slope
is associated with less CC resistance. Inspection of the rubber
specimen surfaces and the flat response of P with increasing num-
ber of cycles for the NR/BR 65CB compound both show that no
significant chipping of rubber was evident for this material which
was reinforced with a significantly higher amount of carbon black
compared to the NR/BR 50CB compound, which showed clear
CC damage.
The development of cutting patterns on the rubber surfaces,
and the related chipping away of material that follows, show dis-
tinct characteristics that depend on normal load (not shown here),
number of impact cycles, and especially the rubber formulation
(figure 6). Along with the P values, such differences in visual
damage responses from cyclic impact reveal that the ICCA can
effectively distinguish the CC behavior of different rubber com-
pounds.
Conclusion
The instrumented chip and cut analyzer is a new test device for
the rubber laboratory that controls and records multiple applied
loads and displacements during cyclic impact to mimic and quan-
tify the cut and chip damage experienced by tire tread compounds
on rough terrain. The surface roughness characteristics of the
rubber specimens, created from the repetitive impacting process,
produce fluctuations in the friction force that are quantified using
the P parameter, thus allowing evaluation of the CC tendency of
rubber compounds in the laboratory to predict CC behavior of tire
treads in service.
Abrasion of rubber involves both mechanical fracture and
thermal-oxidative effects (aging/degradation) (ref. 6). Consider-
ing the latter, impact-induced localized temperature increases of
the rubber during ICCA testing are of interest, and a study was
conducted to investigate this using a high speed, thermal imaging
camera. These preliminary results were shown during the presen-
tation of this paper at the 192nd Meeting of the Rubber Division,
ACS, in October 2017.
In addition to cyclic impact, the ICCA can also be used in full
contact mode as a friction and wear measurement device. This is
an area of ongoing research with this flexible instrument.
References
1. J. Beatty and B. Miksch, “A laboratory cutting and chipping
tester for evaluation of off-the-road and heavy duty tire treads,”
Rubber Chem. Technol. 55, 1,531 (1982).
2. C. Nah, B.W. Jo and S. Kaang, “Cut and chip resistance of
NR-BR blend compounds,” J. Appl. Polym. Sci. 68, 1,537 (1998).
3. M. Scherbakov and M.R. Gurvich, “A method of wear charac-
terization under cut, chip and chunk conditions,” J. Elastom.
Plast. 35, 73 (2003).
4. J.-H. Ma, Y.-X. Wang, L.-Q. Zhang and Y.-P. Wu, “Improvement
of cutting and chipping resistance of carbon black-filled styrene
butadiene rubber by addition of nanodispersed clay,” J. Appl.
Polym. Sci. 125, 3,484 (2012).
((XFKOHU + 0LFKDHO0*HKGH2 .UDWLQD 56WRþHN5
Kipscholl and J.-M. Bunzel, “Wear of technical rubber materials
under cyclic impact loading conditions,” Kautsch. Gummi
Kunstst. 69, 22 (2016).
6. A.N. Gent and C.T.R. Pulford, “Mechanisms of rubber abra-
sion,” J. Appl. Polym. Sci. 28, 943 (1983).
40 RUBBERWORLD.COM JANUARY 2018
Figure 6 - topology of the abraded surfaces
for the NR/BR 65CB and NR/BR 50CB
compounds after testing using loading
conditions described in the text for the
indicated number of impact cycles
Number of impact cycles, n
1,000
2,500
5,000
10,000
15,000
20,000
30,000
40,000
1,000
2,500
5,000
NR/BR 65CB NR/BR 50CB
Figure 7 - effect of number of impact cycles
on P for the NR/BR 65CB and NR/BR 50CB
compounds using conditions described in
the text
Parameter P (N/cycles)
16
14
12
10
8
6
4
2
0
0 10,000 20,000 30,000 40,000
Cycles, n
NR/BR 65CB
NR/BR 50CB
Coming March 2018
Annual Custom Mixing & Custom Services Issue
... However, in the case of off-the-road tires, this contradicts the latest scientific findings reported in [14][15][16][17] that NR is the most resistant material to cutting wear due to its crystallisation at high strains. Thus, while for tires operating on smooth road surfaces, where the treads are loaded with low local deformations causing low local stresses in the tread material, the wear trends for the base polymers are quite clear, i.e. in terms of fatigue abrasion resistance BR > SBR > NR, the abrasion trends for these base polymers have been found to be exactly opposite NR > SBR > BR for tires operating in hard terrain [14,18], which was also confirmed by the tire field test [19]. In [16], the total fatigue crack growth (visualised in Fig. 3 and described later in the chapter) for pure NR and binary NR/SBR mixture from fatigue threshold to ultimate strength was first correlated with CC behaviour. ...
... The following test conditions have been applied for the ICCA analysis: The complete ICCA analyses have been performed in accordance with the testing protocol described in detail previously in Refs. [17][18][19]. If different loads or normal forces are applied, it must be remembered that the low values of load correspond to very low abrasion, called fatigue abrasion, where medium values correspond to abrasive wear and high values correspond to cutting wear. ...
Degradation of Tires During Intended Usage
Chapter
  • Aug 2022
  • ADV POLYM SCI
There are several factors that influence the wear behaviour and service life of tires. Three of them are closely interrelated. They are the tire design, the operating conditions and the rubber material from which the tire is made. One of these factors is of utmost importance and less tangible. It is the choice of the appropriate elastomer, fillers, additives and also vulcanising agents to meet the specific requirements for a particular tire. There are expectations for noise, grip, rolling resistance and comfort, stability as well as safety at the limit (braking, cornering). Alongside this, the biggest challenge in tire development is to extend the lifetime of the tire by increasing resistance to tire degradation, which leads to cracking and wear, as much as possible to reduce overall costs and pollution and to increase sustainability to save resources. All these challenges are the focus of scientists and engineers as long as rubber is used for transport and locomotion of cars, trucks, etc. Moreover, it is difficult to establish correlations between available laboratory tests and real tire tests in the field. Therefore, this chapter gives a brief introduction to the theory of fracture mechanics of rubber leading to wear and shows why analyses with long known laboratory equipment predict a different wear behaviour of rubber than that of a tire in service. Finally, a broad overview is given of novel, high-performance technical measuring equipment with which very reliable experimental results could be obtained that correspond very well to the theory of fracture mechanics and much better to the real tire wear behaviour in service. The recent experimental research impressively demonstrates what a huge step has been taken in the meantime to improve the prediction of wear under specific operating conditions and the design and production for tailor-made tires.KeywordDegradationInstrumented chip & cut analyserIntrinsic strength analyserLifetimeRubberTear and fatigue analyserTireWear
View
... E.g., in Ref. [28], it was reported that the rubber compound rating obtained by means of simple CC test method showed a completely opposite trend to that from the field test. Therefore, an advanced testing method and fully instrumented equipment labelled Instrumented Chip&Cut Analyser (ICCA, Coesfeld GmbH & Co. KG, Germany) has been introduced by Stoček et al. [30,31]. The ICCA method is now successfully integrated as a standard lab method in the rubber respective tyre industry. ...
... In Refs. [30][31][32][33][34], it is shown that the type of rubber polymers and the rubber blend composition significantly influence the CC behaviour over the varied range of applied normal forces. A study comparing the CC behaviour of tyres in the field with laboratory tests has been carried out [32], and laboratory investigations studying the CC behaviour of studied rubber close to tyre application have also been carried out, but without direct comparison to field tests [35,36]. ...
The Effect of Apparent Cross-Link Density on Cut and Chip Wear in Natural Rubber
Chapter
  • Jul 2022
  • ADV POLYM SCI
Natural rubber is a polymer that, by inducing crystallization at a certain level of stress, contributes significantly to reducing cut and chip (CC) damage to rubber articles when exposed to harsh conditions. This unique property is dependent on several factors, including the processing conditions, the cross-linking system and the type of additives used, resulting in varying apparent cross-link density (CLD) of the cross-linked CB filled rubber. Therefore, this work focuses on the systematic investigation of CC phenomena as a function of CLDs represented by conventional (CV), semi-efficient (SEV) and efficient (EV) cross-linking systems. Rubber samples based on different cross-linking systems were prepared by varying the concentration of the accelerator N-tert-butylbenzothiazolesulfonamide (TBBS) at a constant concentration of 2.5 phr sulfur as a cross-linking agent. The different CLDs were achieved by different concentration ratios (A/S) between accelerator (A) and sulfur (S), using A/S = 0.1, 0.3, 0.6 for the CV system, A/S = 0.7, 1.0, 1.5, 2.0, 2.5 for the SEV system and A/S = 3.0 for the EV system. First, the basic mechanical behaviour was presented as a function of CLD, with the optimal behaviour found in the range of 181–241 μmol × cm−3. The CC resistance is independent of the CLD when the rubber specimens are loaded with a normal force of 100 N. However, at higher load, the optimal range of CLD decreases rapidly from 136 to 241 μmol × cm−3. Furthermore, a significant influence of SIC on CC resistance was confirmed in the range of CLD from 181 to 241 μmol × cm−3. Moreover, in the range of CLD from 181 to 241 μmol × cm−3 the predominant effect of NR on CC resistance was observed. Finally, an effect of degradation of cross-link network on CC properties due to rubber curing in the reversion has been discussed.KeywordsAcceleratorsCross-link densityCut and chip wearLaboratory testingNatural rubberRubberStrain induced crystallizationSulfur
View
... Such simple CC test methods show for certain specimen geometries and loading conditions how the rate of abrasion can be predicted only in a qualitatively approximate manner. Therefore, an advanced testing method and fully instrumented equipment labelled Instrumented Chip and Cut Analyser (ICCA, Coesfeld GmbH, Germany) has been introduced by Stoček et al. [11,12]. The ICCA method is now successfully integrated as a standard lab method in the rubber industry. ...
... We refer to recent references [11][12][13]20] regarding the impacting device, the impactor geometry and the description of the independent control of the impact frequency and the sliding time. ...
Cut & chip wear of rubbers in a range from low up to high severity conditions
Article
Full-text available
  • Dec 2021
The development of cut and chip (CC) resistant rubber articles, composed of rubber blends, requires a detailed understanding and a controlled estimation of the CC behavior of each separate rubber component within the blend in a wide range of severity conditions. This study is focused on comparative CC investigations of NR, SBR and NR/SBR (50:50) rubber blends using an Instrumented Chip and Cut Analyser (ICCA, Coesfeld GmbH, Germany) in a broad range of loading conditions. We show the results for the CC effects dependant on the applied normal forces from 90 to 200 N during cyclic impact damaging and the evolution of the temperature on the surface of the damaged specimen. We find significant differences between the used rubbers regarding dependence on the damage parameters and temperature on the normal load which determines the severity to which the rubber is exposed. In the case of NR evolving the CC damage and temperature goes through a maximum at critical values of the impacting normal load. This effect is briefly discussed in the context of the appearance of strain-induced crystallization (SIC) in the NR during cyclic impacts above a critical level. The results impressively explain the empirical preference for NR or NR-blends in practice when it comes to minimizing CC wear.
View
... Refs. [12,13,30,34,35]. Testing with the ICCA involves rotating the rubber sample at a selected rotational speed and impacting the sample with a stainless steel tool with specified frequency. ...
... The inside specific geometry of the sample is purposefully designed for assuring exact fixing of the sample in the device for maintaining constant position and prevention against the slippage during the dynamic impact. More details on impacting device, impactor geometry and description of the independent control of impact frequency and sliding time can be found in recent references [12,13,30,34,35]. ...
Fatigue Crack Growth vs. Chip and Cut Wear of NR and NR/SBR Blend-Based Rubber Compounds
Chapter
  • Nov 2020
  • ADV POLYM SCI
Tyre tread directly comes in contact with various road surfaces ranging from very smooth roads up to riding on rough road surfaces (e.g. gravel roads, roots, stalks) and is prone to damage due to cut from sharp asperities during service. As tyre experiences millions of fatigue cycles in its service life, these cuts propagate continuously and lead to varied fracture processes from simple abrasion, crack growth up to catastrophic failure. In this paper firstly the complete fatigue crack growth (FCG) characteristics of rubbers from the endurance limit up to the ultimate strength and, finally, compared the data with a fast laboratory testing method determining the Chip and Cut (CC) behaviour. The study is focussed on investigation of pure natural rubber (NR) and natural rubber/styrene butadiene rubber (NR/SBR) blends, based on industrial compound formulations used for tyre tread applications. These rubbers have well-established FCG characteristics in field performance of tyre treads, with NR exhibiting the higher FCG resistance at high region of tearing energies, whereas the advantage of SBR over NR can be realized in terms of the higher fatigue threshold for SBR occurring in the low range of tearing energies. The same trend was found from the FCG analyses consisting of the complete Paris-Erdogan curve from endurance limit up to ultimate strength as well as CC behaviour determined with a laboratory Instrumented Chip and Cut Analyser (ICCA) which operates under realistic practice-like conditions and quantifies the CC behaviour using a physical parameter.
View
... Cut and chip wear testing has been performed in the field for scientific research. Some experiments [3,4,[7][8][9][10] showed similar cut and chip resistance ranking to comparable materials tested in the laboratory while a few [11] did not show correlation between the field and laboratory tests. Performing cut and chip wear testing in the field can be costly and it is also difficult to perform controlled, repeatable tests. ...
View
... Testing device and principles of the testing procedures are described in [36][37][38][39][40] and the complete ICCA analyses have been performed in accordance to the testing protocol described in detail previously in [6,10]. ...
View
... Cut and chip wear testing has been performed in the field for scientific research. Some experiments [3,4,[7][8][9][10] showed similar cut and chip resistance ranking to comparable materials tested in the laboratory while a few [11] did not show correlation between the field and laboratory tests. Performing cut and chip wear testing in the field can be costly and it is also difficult to perform controlled, repeatable tests. ...
View
... Moreover, this phenomenon is also observed with highway commercial truck as well as all-season passenger car and touring moto-bike tires. To avoid intensive field tests of tires, Stoček et al. introduced an advanced testing method and fully instrumented equipment labelled Instrumented Chip&Cut Analyzer (ICCA, Coesfeld GmbH & Co. KG, Germany) [32,33]. The ICCA method is meanwhile successfully integrated as a standard lab method in the rubber respective tire industries. ...
Basic Mechanisms and Predictive Testing of Tire-Road Abrasion
Chapter
  • Mar 2022
  • ADV POLYM SCI
The chapter provides a brief overview of the abrasion mechanisms occurring on automotive tires. Particular attention is paid to fatigue abrasion, which is especially the cause of mass loss in passenger car tires in public road traffic. The framework of the paper is a very simple physical model (Resnikowskij, Kautschuk Gummi Kunststoffe 9:33–37, 1960) of the relationship between abrasion and friction work during Hertzian contact and sliding friction of rubber over the periodical roughness of a road. Essential physical quantities of the rubbers determined in the laboratory, such as modulus, tensile elongation, coefficient of friction, and a Woehler-like fatigue parameter, give an expression for laboratory fatigue wear that correlates very well with tire wear under an outdoor test program commonly used by tire companies on public highways. This result also makes it clear why tire wear under moderate severity conditions cannot be described by abrasive wear tests in the laboratory, e.g. with DIN-Abrader.
View
... Laboratory chip and cut testing was performed on the rubber specimens using the instrumented chip and cut analyser [7,8] (ICCA TM ) manufactured by Coesfeld GmbH, Germany and distributed in the Americas by Endurica LLC, USA. Continuous improvements of this equipment since the prototype was described in 2013 [9] have led to the current fully-instrumented version that will be further described in the next section. ...
Characterisation of cut and chip behaviour for NR, SBR and BR compounds with an instrumented laboratory device
Article
  • May 2018
Understanding the cut and chip (CC) effect in rubber is important for successful product development for tires used in off-road or poor road conditions and for other demanding applications of rubber. This research describes a laboratory testing method for characterising the CC fracture behaviour of rubber using a device that controls and records multiple applied loads and displacements during cyclic impact to the surface of a solid rubber specimen to mimic and quantify the CC damage experienced by tire tread compounds. To study the capabilities of the instrument, three model compounds were studied that are based on carbon black reinforced compounds of common elastomers used in tire treads: natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). These polymers have well-established CC tendencies in field performance of tire treads, with NR exhibiting the best CC resistance followed by SBR and finally BR. The same trend was found with the rubber impact testing approach that allowed the CC behaviour to be quantified using a new physical parameter which is the CC propensity (P). The relative ranking for CC resistance for the three compounds followed the fatigue crack growth resistances of the materials but was exactly opposite to the ranking of DIN abrasion resistance. This provides evidence that CC damage from impact by mm-scale asperities and abrasion of rubber against μm-scale asperities exhibit distinct characteristics in rubber.
View
A Method of Wear Characterization Under Cut, Chip and Chunk Conditions
Article
Full-text available
  • Jan 2003
A new experimental method and corresponding analytical model were proposed to characterize cut, chip and chunk wear for elastomeric materials. According to the model, the wear is considered as a time-dependent nonlinear process. Experimental verification of the proposed model was conducted for four typical elastomers. It was shown that the amount of wear loss may be accurately described by the model, based on two independent material parameters. The effect of each parameter on cut, chip and chunk wear resistance was analyzed in detail. High statistical reliability was shown for the proposed material parameters and corresponding analytical predictions. The proposed method may be recommended as a robust predictor of cut, chip and chunk wear processes for rubber and, potentially, other polymer materials.
View
A Laboratory Cutting and Chipping Tester for Evaluating off-the-Road and Heavy-Duty Tire Treads
Article
  • Nov 1982
A laboratory cutting and chipping test for off-the-road, (OTR) and heavy duty, (HD) tires has been developed that predicts service performance with reasonable speed and accuracy. Cutting and chipping has been defined, and an analysis of the factors thought to be involved in cutting and chipping has been attempted so the necessary criteria for a test could be developed. The data discussed show that the necessary physical properties for superior OTR treads are not easily or simply defined. It was found that the reinforcing blacks improve cutting and chipping resistance in approximately the order of their improvement of road test abrasion on a tire. High hysteresis or tan delta is desirable, but must be reduced or compromised for treads of tires where high temperature generation is encountered, such as long, fast hauls with OTR tires.
View
Improvement of cutting and chipping resistance of carbon black‐filled styrene butadiene rubber by addition of nanodispersed clay
Article
  • Sep 2012
AbstractA novel, effective approach to improve the cutting and chipping resistance (CCR) of carbon black (CB)‐filled styrene butadiene rubber (SBR) composite was reported in this study. CCR of SBR was dramatically improved more than 30% by addition of 4 phr nanodispersed clay (NC), while not decreasing the stress at 100% and the Shore A hardness of the composite. The curing characteristics, loss tangent (tan δ), and the strength of filler network of the composites were further measured by a Disk Oscillating Rheometer and a rubber processing analyzer, respectively. It was found that the addition of NC led to a slightly lower crosslink density, higher tan δ, and stronger filler network, which contributed to the higher CCR. Therefore, the novel layered NC is more efficient in improving CCR when compared with CB. The results are expected to promote the application of NC in rubber industry. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
View
Cut and chip resistance of NR–BR blend compounds
Article
The laboratory cut and chip resistance of natural rubber/polybutadiene rubber (NR-BR) blends was determined using B.F. Goodrich cut and chip tester. The resistance to cut and chip of the BR was considerably higher than that of NR. The hardness, stress at 300% elongation, and stress at break were observed to decrease with increasing BR content. The frictional coefficient of carbon black-filled NR (FNR) was about two times higher than that of carbon black-filled BR (FBR), indicating that higher frictional energies were subjected to the FNR specimen. The rebound of the blend increased with increasing BR content.
View
Mechanisms of rubber abrasion
Article
In the reported experiments, rates of wear have been determined for several elastomer materials, using a razor-balde abrading apparatus based on one described by Champ, Southern, and Thomas. Measurements have been carried out at different levels of frictional power input, corresponding to different severities of wear, at both ambient temperature and at 100 degree C, and both in air and in an inert atmosphere. It is concluded that wear occurs as a result of two processes: local mechanical rupture (tearing) and general decomposition of the molecular network to a low-molecular-weight material (smearing). Marked differences were shown by different elastomers. Carbon-black-filled natural rubber, SBR (styrene-butadiene copolymer) and EPR (ethylene-propylene copolymer) were particularly susceptible to decomposition and smearing but for natural rubber and SBR the decomposition process was not observed in an inert atmosphere. Several observations suggest that wear, even in the absence of smearing, is not fully correlated with mechanical fatigue: the markedly lower wear rates for carbon-black-filled materials, the anomalous rankings of unfilled materials, and the relatively small effects of raising the test temperature to 100 degree C. It is concluded that abrasive wear by small-scale tearing is not accounted for solely by the crack growth properties of the material but involves other failure processes as well.
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Wear of technical rubber materials under cyclic impact loading conditions
  • Jan 2016
  • 22
  • J.-M Kipscholl
  • Bunzel
Kipscholl and J.-M. Bunzel, "Wear of technical rubber materials under cyclic impact loading conditions," Kautsch. Gummi Kunstst. 69, 22 (2016).