TYPE O iginal Resea ch
PUBLISHED 06 Feb ua y 2024
DOI 10.3389/ ma s.2024.1348265
OPEN ACCESS
EDITED BY
Na ayan L,
Sa ee ha Uni e si y, India
REVIEWED BY
Ji end a Kuma Ka iya ,
SRM Ins i u e o Science and Technology,
India
Sa hish Kuma Palaniappan,
King Mongku ’s Uni e si y o Technology
No h Bangkok, Thailand
Felix Sahaya aj A,
Kalaigna ka unanidhi Ins i u e o Technology
(KIT), India
Chand asekha a Sas y C,
Indian Ins i u e o In o ma ion Technology
Design and Manu ac u ing, India
*CORRESPONDENCE
Mi hul Naidu,
[email p o ec ed]
RECEIVED 02 Decembe 2023
ACCEPTED 11 Janua y 2024
PUBLISHED 06 Feb ua y 2024
CITATION
Naidu M, Bhosale A, Gaikwad M, Salunkhe S,
Čep R and Abouel Nas E (2024), T ibological
in es iga ions o hemp ein o ced NAO b ake
ic ion polyme composi es wi h a ying
pe cen age o esin loading.
F on . Ma e . 11:1348265.
doi: 10.3389/ ma s.2024.1348265
COPYRIGHT
© 2024 Naidu, Bhosale, Gaikwad, Salunkhe,
Čep and Abouel Nas . This is an open-access
a icle dis ibu ed unde he e ms o he
C ea i e Commons A ibu ion License (CC
BY). The use, dis ibu ion o ep oduc ion in
o he o ums is pe mi ed, p o ided he
o iginal au ho (s) and he copy igh owne (s)
a e c edi ed and ha he o iginal publica ion
in his jou nal is ci ed, in acco dance wi h
accep ed academic p ac ice. No use,
dis ibu ion o ep oduc ion is pe mi ed
which does no comply wi h hese e ms.
T ibological in es iga ions o
hemp ein o ced NAO b ake
ic ion polyme composi es wi h
a ying pe cen age o esin
loading
Mi hul Naidu1*, Aji Bhosale2, Mahesh Gaikwad3,
Sachin Salunkhe4, Robe Čep5and Emad Abouel Nas 6
1Depa men o Mechanical Enginee ing, Sh ima i Kashibai Na ale College o Enginee ing, Sa i ibai
Phule Pune Uni e si y, Pune, India, 2Depa men o Mechanical Enginee ing, MKSSS’s Cummins
College o Enginee ing o Women, Pune, India, 3Depa men o Mechanical Enginee ing, JSPM’S
Jayawan ao Sawan College o Enginee ing, Pune, India, 4Depa men o Mechanical Enginee ing,
Gazi Uni e si y, Anka a, Tu key, 5Depa men o Machining, Assembly and Enginee ing Me ology,
Facul y o Mechanical Enginee ing, VSB-Technical Uni e si y o Os a a, Os a a, Czechia,
6Depa men o Indus ial Enginee ing, College o Enginee ing, King Saud Uni e si y, Riyadh, Saudi
A abia
NAO b ake ic ion ma e ials wi h 4%, 5%, and 6% (w/ ) sodium hyd oxide ea ed
hemp ibe ein o cemen ha ing 25% w . ibe loading and ixed pe cen age o
phenol o maldehyde esin con en (20% w .) along wi h o he ille s ha e been
s udied and epo ed by he au ho s ea lie . Howe e , he e ec o a ia ions in
he esin con en on he ibological pe o mance has been s udied and epo ed
in he p esen pape . Fi e a ian s we e p epa ed wi h a ying pe cen ages o
phenol o maldehyde esin om 12% w . o 22% w . wi h inc emen al s eps o
2% w , along wi h he op imum o 6% (w/ ) sodium hyd oxide ea ed hemp
ibe s and o he ille s. The p epa ed es a ian s’ ibological cha ac e iza ion
was done using Taguchi’s L25 o hogonal a ay on a pin-on-disc expe imen al
se up, as pe ASTM G99, a oom empe a u e and compa ed wi h he bes o
he ea lie s udied ic ion composi e. Fade and eco e y es s o he bes o he
ea lie s udied and p esen ones we e pe o med on a chase ibology es e
pe SAE J661 s anda ds. The esul s e ealed mode a e coe icien o ic ion o
0.4496, lowe wea a e o 0.57gm, and be e ade eco e y o he HF25P20
a ian compa ed o i s coun e pa s s udied he e.
KEYWORDS
hemp ibe s, phenol o maldehyde, ade- eco e y, ano a, Taguchi, Scanning elec on
mic oscopy
1 In oduc ion
B ake pads a e pa o he b ake sys em componen s along wi h he mas e cylinde ,
wheel cylinde , and hyd aulic con ol sys em. B ake pads ha e a ac ed much esea ch
in e es due o hei na u e and impac on he en i onmen (Naidue al., 2023). Binde s,
ic ion modi ie s, ille s, and ein o cemen s a e ou ca ego ies o ma e ials used in
he manu ac u e o b ake pads (A angana han and Bijwe, 2016;IbukunOlabisi, 2016;
Mu lu, 2009). Biomass om ag icul u al ac i i ies like ege ables, animal exc emen ,
F on ie s in Ma e ials 01 on ie sin.o g
Naidu e al. 10.3389/ ma s.2024.1348265
ag icul u al esidue, lea es, s ems, ui s, seeds, g asses, and eeds
a e ending ma e ials o p oducing comme cially accep ed b ake
pads ha a e en i onmen ally iendly. Palm ke nel shells, bamboo,
co n s alks, suga cane bagasse, banana, cashew nu shell, coi
(coconu shell), ice s aw, pineapple, ice husks, hemp, e c. o m
he ein o cing agen s. F ic ion modi ie s o ille s in na u al ib e
ic ion ma e ials (Joshie al., 2023). The p esen au ho s p epa ed
and in es iga ed he p ope ies o b ake ic ion ma e ial wi h 4,5%
and 6% (w/ ) NaOH- ea ed hemp ibe ein o cemen s ha ing 25%
w . ibe loading and wi h 20% w . o phenol o maldehyde esin
con en , along wi h o he ille s, in o de o unde s and he e ec
o he a ia ion in he concen a ion o sodium hyd oxide (NaOH)
on he ibological pe o mance o 20% w . phenol o maldehyde
binde con ained ic ion ma e ial (Naidue al., 2023). The esul s
e ealed be e p ope ies o he ic ion ma e ial wi h 6% (w/ )
NaOH- ea ed hemp ibe s. Howe e , o u he unde s and he
in luence o g adual inc emen o he esin con en be ween 10% and
20% w ., whe ein esul s wi h 10% w . we e al eady a ailable wi h he
au ho s, he p esen pape ocuses on s udying he e ec o phenol
o maldehyde esin con en a ia ion on he 6% (w/ ) NaOH-
ea ed hemp ibe s ein o ced ic ion composi e wi h simila ille
con en s. Fi e a ian s we e p epa ed wi h a ying pe cen ages
o phenol o maldehyde esin om 12% w . o 22% w . wi h
inc emen al s eps o 2% w and 6% (w/ ) NaOH- ea ed hemp ibe s
and o he ille s. T ibological cha ac e iza ion o p ope ies, namely,
Speci ic Wea Ra e (SWR) and Coe icien o F ic ion (COF) o he
p epa ed es a ian s was done using a pin-on-disc expe imen al
se up, as pe ASTM G99, a oom empe a u e and compa ed wi h
he bes o he ea lie s udied ic ion composi e, namely, HF25P20
(ea lie named HF6P20) ha ing SWR o 3.5417 × 10−5mm3/Nm
and COF o 0.4496. Fade and eco e y es s o he bes o he
ea lie s udied ic ion composi e, namely, HF25P20 and he p esen
one, we e pe o med on a chase ibology es e as pe SAE J661
s anda ds. The esul s e ealed mode a e COF (wi hin accep able
s anda d limi s), lowe wea a e, and be e ade eco e y o he
HF25P20 a ian compa ed o i s coun e pa s s udied he e.
2 Ma e ials and me hods
2.1 Fab ica ion o composi es
Hemp ibe s we e sou ced om Hemp A ai P . L d. in
Va anasi and unde wen a chemical ea men o 24h using sodium
hyd oxide (NaOH) aqueous solu ion wi h a concen a ion o 6%
(w/ ). Following his ea men , hey we e ho oughly insed wi h
dis illed wa e and d ied unde sunligh o 10h. The hemp ibe s
we e cu in o leng hs anging om 3 o 5mm Table1 displays
he componen s’ p opo ions used in c ea ing he es composi es.
These componen s include ba ium sul a e as a non- unc ional
ille , hemp ibe s o ein o cemen , phenol- o maldehyde se ing
as a binde , g aphi e ac ing as a d y lub ican , and e miculi e
and alumina se ing as p ope y modi ie s (Naidue al., 2023;
Rajake al., 2019;Singhe al., 2019). Howe e , o unde s and he
in luence o g adual inc emen o he esin con en be ween 10%
and 20% w ., whe ein 10% w . esul s we e al eady a ailable wi h
he au ho s; he inc emen o esin was done om 12% w . onwa ds.
Inc emen s eps o 2% w . was selec ed as i was unde s ood ha
a leas 2% w . s ep was equi ed o obse e he in luence o he
esin a ia ions on he ibological pe o mance o he ic ion
composi es.
Fi e composi ions ( a ian s) we e de eloped using he
ing edien s shown in Table1, HF25P12, wi h 12%w . phenol
o maldehyde (PF) esin, HF25P14–wi h 14%w . PF esin,
HF25P16–wi h 16%w . PF esin, HF25P18–wi h 18%w . PF esin
and HF25P22–wi h 22%w . PF esin. 6% (w/ ) alkali p e- ea ed
hemp ibe s wi h 25%w . ibe loading was used o all hese
composi ions. The PF con en compensa ed o he ba ium sulpha e
con en . HF25P20 was al eady ab ica ed and es ed in he au ho s’
ea lie wo k (Naidue al., 2023), which was hen e med HF6P20;
hence, i was no e ab ica ed he e.
All he componen s we e me iculously measu ed using a digi al
scale (Wensa ®e al.: 0–220g, Leas Coun : 0.01g). The chopped
ibe s and he phenolic powde o mula ions we e subjec ed o a d y
mixing p ocess o 15mina a o a ional speed anging om 250
o 500 e olu ions pe minu e ( pm) using a mechanical s i e o
a ain a uni o m blend. Figu e1A illus a es ha he mix u es we e
hen subjec ed o comp ession in a comp ession molding machine
(Manu ac u e : San ec). The mixes we e cu ed o 10min, wi h
ou b ea hings o applied p essu e a 15MPa and a empe a u e
o 155°C. Fo 3h, a pos -cu ing p ocess was ca ied ou in a
ho ai o en (Manu ac u e : A hena Technology), as depic ed in
Figu e1B, a 170°C. This s ep was pe o med o elimina e mois u e
and elease any apped gases ha may ha e o med du ing he
polyme iza ion p ocess o he ma ix cons i uen s, he eby elie ing
induced comp essi e s esses (Singhe al., 2019).
Pla es o i e di e en composi ions, iden i ied as HF25P12,
HF25P14, HF25P16, HF25P18, and HF25P22, wi h dimensions
measu ing 100 × 100 × 10mm in hickness, we e ab ica ed u ilizing
he comp ession molding me hod. F om each ype o composi ion,
specimens o conduc ing a pin-on-disc es by ASTM G 99 and a
ade and eco e y es as ou lined in SAE J661 we e ex ac ed om
hese 100 × 100 × 10mm pla es. Th ee es specimens o each ype
we e ex ac ed. A sample o his is illus a ed in Figu e2.
2.2 T ibological cha ac e iza ion
2.2.1 Design o expe imen s using o hogonal
a ay
T ibological p ope ies, pa icula ly speci ic wea a e (SWR)
and coe icien o ic ion (COF) we e analyzed using he Taguchi
expe imen design. Taguchi’s expe imen design conside s ac o s
i e ms as “signals,” which con ol he p ocess esponse e alua ed
a di e en le els. Composi ion, no mal (b aking) load, and sliding
eloci y in luenced SWR and COF. The alues o he sliding
eloci ies and he no mal loads we e decided om ea lie li e a u e
(Rashide al., 2017a;Shanmughasunda am, 2017). Table2 shows
he ac o s and le els selec ed o he ic ion composi es.
2.2.2 Expe imen al p ocedu e
To assess he ibological pe o mance o SWR and COF o he
p epa ed hemp/PF ic ion bio-composi es a oom empe a u e,
hey we e es ed on a pin-on-disc expe imen al se up (DUCOM™
TR-20LE)aspe ASTMG99s anda ds, asshown in Figu e3.A ack
diame e o 100mm o a 5,000m sliding dis ance was selec ed.
F on ie s in Ma e ials 02 on ie sin.o g
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TABLE 1 Ma e ial composi ion.
Ma e ials Weigh con ibu ion (%)
HF25P12 HF25P14 HF25P16 HF25P18 HF25P22
Hemp ibe s 25 25 25 25 25
Phenol o maldehyde 12 14 16 18 22
G aphi e powde 5 5 5 5 5
Ve miculi e 5 5 5 5 5
Alumina 5 5 5 5 5
Ba ium sulpha e 48 46 44 42 38
To al 100 100 100 100 100
FIGURE 1
(A) Comp ession moulding machine (B) Ho ai o en.
TABLE 2 Fac o s and le els.
Fac o s Uni s Le el 1 Le el 2 Le el 3 Le el 4 Le el 5
Composi ion - HF25P12 HF25P14 HF25P16 HF25P18 HF25P22
Load N 30 50 70 90 110
Sliding Veloci y m/s 2.6 3.9 5.2 6.5 7.8
The es ials we e conduc ed pe Taguchi L25 o hogonal a ay
combina ions, whe ein h ee ac o s we e e alua ed o i e le els,
as shown in Table2.
Speci ica ions o he pin-on disc se up used.
Make: DUCOM™ TR-20LE.
➢ Disc speed: 200 pm–2000 pm (in s ep o 1 pm)
➢ Disc size: Dia.165 × 8mm hick
➢ Disc ma e ial: J431 (22–24 HRC, g ound o 1.6 Ra
su ace oughness)
➢ No mal load: 2kg–20kg (s ep o 0.5kg by dead weigh s)
➢ F ic ion o ce: 0–200N (leas coun : 0.1N)
➢ Wea : 0–2000 mic ons (leas coun : 1 mic on)
F on ie s in Ma e ials 03 on ie sin.o g
Naidu e al. 10.3389/ ma s.2024.1348265
FIGURE 2
Sample specimen o pin on disc es .
FIGURE 3
Pin-on-Disc Expe imen al se up.
Mass loss a ising om ubbing o he es specimens agains
he o o o he pin-on disc se up was measu ed using an analy ical
weighing balance (Wense make, model MAB 201) wi h an accu acy
o 0.1mg. The mass loss so ob ained o h ee di e en es
specimens o each ype o composi ion we e used o calcula e hei
espec i e SWR using he ela ion (a).
Fade and eco e y analysis o he composi es pe o ming be e
a oom empe a u e amongs hose in es iga ed we e done on
a Chase dynamome e ollowing SAE J661 s anda ds a Indian
F ic ion Ma e ial Enginee ing Company, Noida, India. A Chase
dynamome e comp ises a spinning d um wi h a 25.4-mm-squa e
ic ion pad p essed agains i s inne ci cum e ence using an ai
p essu e mechanism. A mino po ion o he ic ion ma e ial
con ac s he d um o collec in o ma ion ega ding ic ion and wea
(Akincioğlue al., 2021).
3 Resul s and discussion
Taguchi Design o Expe imen s (D.O.E.) was conduc ed wi h
h ee ac o s - composi ion, load and sliding eloci y, and each
ac o wi h i e a ying le els as shown in Table2. L25 o hogonal
a ay was sugges ed by Taguchi design o expe imen me hod o
h ee ac o s and i e le els. The de i ed expe imen s we e used o
ibological es ing on a Pin-on-Disc ibo-machine (as pe ASTM
G99) a oom empe a u e. Subsequen ly, Speci ic Wea Ra e (SWR)
and Coe icien o F ic ion (COF) we e ob ained using he Eqs1,2as
shown below and analyzed using S/N a ios o decide he op imum
pa ame e s.
SWR =∆m
ρLD (1)
COF =F
L(2)
Whe e,
∆m=massloss
ρ=densi y
L= applied load.
D= sliding dis ance.
F= ic ional o ce.
3.1 Signal- o-noise a io
The SWR and COF alues we e ans o med in o Signal- o-
Noise (S/N) a ios, wi h he goal o minimizing bo h o hem,
making use o he “Smalle is Be e ” quali y cha ac e is ic. The
o mula o compu ing he co esponding S/N a io is ep esen ed
by Eq.3as shown.
S
N a io =−10log10 {1
n∑n
i=1y2
i}(3)
Whe e, y = SWR o COF n= Numbe o ials.
The pu pose is o compu e he highes signal- o-noise a io
which means he e a e minimum andom ac o s (noise) a ec ing
he equi ed pa ame e s. The alues o S/N a ios a e abula ed in
Table3.
3.2 Va ia ion o ic ion o ce (F), SWR and
COF wi h espec o no mal load
Va ia ion o ic ion o ce wi h espec o ime we e eco ded o
all i e composi ions a 30N, 50N, 70N, 90N, and 110N no mal
loads as shown in Figu es4A–E o HF25P12, HF25P14, HF25P16,
HF25P18 and HF25P22 espec i ely.
The esul s ypically showed wo ic ion egimes, ini ially
a unning-in pe iod ollowed by a s eady-s a e pe iod simila
o hose epo ed in ea lie li e a u e o sliding ic ion cases
(Chand and Fahim, 2008). These egimes we e due o he highe
F on ie s in Ma e ials 04 on ie sin.o g
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TABLE 3 Speci ic wea a e (SWR) and coe icien o ic ion (COF) using L25 o hogonal a ay wi h 3 eplica es.
Load (N) Sliding eloci y (m/s) Composi ion SWR (mm3/Nm) × 10–5 COF S/N o SWR S/N o COF
30 2.6 H25P12 9.5645 0.65 −20.20302982 3.522693814
30 2.6 H25P12 10.2365 0.67 ∗ ∗
30 2.6 H25P12 11.3658 0.7 ∗ ∗
50 3.9 H25P12 7.3265 0.58 −18.76558992 4.436974992
50 3.9 H25P12 8.6752 0.6 ∗ ∗
50 3.9 H25P12 9.3658 0.62 ∗ ∗
70 5.2 H25P12 7.2956 0.55 −18.3139049 4.753932734
70 5.2 H25P12 8.2356 0.58 ∗ ∗
70 5.2 H25P12 9.3658 0.62 ∗ ∗
90 6.5 H25P12 6.3545 0.53 −17.89285537 5.104755259
90 6.5 H25P12 7.8459 0.56 ∗ ∗
90 6.5 H25P12 8.3568 0.52 ∗ ∗
110 7.8 H25P12 6.9568 0.51 −17.05642879 5.39727992
110 7.8 H25P12 7.1256 0.54 ∗ ∗
110 7.8 H25P12 8.3654 0.58 ∗ ∗
30 2.6 H25P14 7.3548 0.57 −18.61531406 4.436974992
30 2.6 H25P14 8.5264 0.6 ∗ ∗
30 2.6 H25P14 9.3265 0.63 ∗ ∗
50 3.9 H25P14 6.6598 0.52 −17.22291882 5.03623946
50 3.9 H25P14 7.2635 0.56 ∗ ∗
50 3.9 H25P14 8.6589 0.59 ∗ ∗
70 5.2 H25P14 5.1415 0.51 −16.32296928 5.30720322
70 5.2 H25P14 6.5486 0.54 ∗ ∗
70 5.2 H25P14 7.3568 0.57 ∗ ∗
90 6.5 H25P14 4.6959 0.49 −15.50244732 5.661578537
90 6.5 H25P14 5.9583 0.52 ∗ ∗
90 6.5 H25P14 6.3659 0.54 ∗ ∗
110 7.8 H25P14 4.4897 0.48 −15.41026554 5.863938059
110 7.8 H25P14 5.8954 0.51 ∗ ∗
110 7.8 H25P14 6.3569 0.54 ∗ ∗
30 2.6 H25P16 6.3698 0.55 −17.8691319 4.779494966
30 2.6 H25P16 7.8245 0.58 ∗ ∗
30 2.6 H25P16 8.3365 0.62 ∗ ∗
(Con inued on he ollowing page)
F on ie s in Ma e ials 05 on ie sin.o g

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TABLE 3 (Con inued) Speci ic wea a e (SWR) and coe icien o ic ion (COF) using L25 o hogonal a ay wi h 3 eplica es.
Load (N) Sliding eloci y (m/s) Composi ion SWR (mm3/Nm) × 10–5 COF S/N o SWR S/N o COF
50 3.9 H25P16 5.1256 0.51 −15.74339806 5.352124804
50 3.9 H25P16 6.1259 0.54 ∗ ∗
50 3.9 H25P16 7.6959 0.59 ∗ ∗
70 5.2 H25P16 4.1256 0.48 −14.52769707 5.644926136
70 5.2 H25P16 5.3258 0.52 ∗ ∗
70 5.2 H25P16 5.6895 0.55 ∗ ∗
90 6.5 H25P16 4.2635 0.46 −13.15812779 6.018862909
90 6.5 H25P16 4.5489 0.5 ∗ ∗
90 6.5 H25P16 5.6329 0.54 ∗ ∗
110 7.8 H25P16 3.2639 0.46 −12.33077053 6.180139358
110 7.8 H25P16 4.1356 0.49 ∗ ∗
110 7.8 H25P16 5.2635 0.52 ∗ ∗
30 2.6 H25P18 6.1254 0.49 −17.09765387 5.460568326
30 2.6 H25P18 7.1595 0.53 ∗ ∗
30 2.6 H25P18 8.1265 0.57 ∗ ∗
50 3.9 H25P18 4.1256 0.48 −14.5920421 5.679933127
50 3.9 H25P18 5.3654 0.52 ∗ ∗
50 3.9 H25P18 6.6359 0.57 ∗ ∗
70 5.2 H25P18 3.9256 0.47 −12.28781894 6.020599913
70 5.2 H25P18 4.1152 0.5 ∗ ∗
70 5.2 H25P18 4.5364 0.54 ∗ ∗
90 6.5 H25P18 2.1154 0.43 −10.43740023 6.460643714
90 6.5 H25P18 3.3256 0.48 ∗ ∗
90 6.5 H25P18 4.3679 0.53 ∗ ∗
110 7.8 H25P18 2.5556 0.43 −9.416438991 6.697765258
110 7.8 H25P18 2.9568 0.46 ∗ ∗
110 7.8 H25P18 3.9246 0.5 ∗ ∗
30 2.6 H25P22 5.3249 0.47 −15.74297268 5.980736437
30 2.6 H25P22 6.1256 0.5 ∗ ∗
30 2.6 H25P22 7.3659 0.53 ∗ ∗
50 3.9 H25P22 3.1258 0.46 −13.15755494 6.158932699
50 3.9 H25P22 4.5486 0.49 ∗ ∗
50 3.9 H25P22 5.2359 0.52 ∗ ∗
(Con inued on he ollowing page)
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TABLE 3 (Con inued) Speci ic wea a e (SWR) and coe icien o ic ion (COF) using L25 o hogonal a ay wi h 3 eplica es.
Load (N) Sliding eloci y (m/s) Composi ion SWR (mm3/Nm) × 10–5 COF S/N o SWR S/N o COF
70 5.2 H25P22 2.2369 0.46 −9.892830206 6.532208436
70 5.2 H25P22 3.1235 0.47 ∗ ∗
70 5.2 H25P22 4.3215 0.51 ∗ ∗
90 6.5 H25P22 2.052 0.43 −6.550039451 7.068004966
90 6.5 H25P22 2.1257 0.44 ∗ ∗
90 6.5 H25P22 3.3469 0.49 ∗ ∗
110 7.8 H25P22 2.0007 0.41 −7.792534479 5.560491968
110 7.8 H25P22 2.4526 0.46 ∗ ∗
110 7.8 H25P22 3.3215 0.49 ∗ ∗
TABLE 4 ANOVA o S/N a io o speci ic wea a e.
Sou ce DOF Seq. SS Adj. SS Adj. MS F Value p-Value Con ibu ion (%)
Load 4 105.619 105.619 26.405 23.27 0.000 33.15
Sliding eloci y 4 9.240 9.240 2.310 2.04 0.153 2.90
Composi ion 4 190.045 190.045 47.511 41.86 0.000 59.66
E o 12 13.619 13.619 1.135 - -
To al 24 318.523 - - - -
Seq. SS, sequen ial sum o squa es, Adj; SS , adjus ed sum o squa es, Adj; MS , adjus ed mean squa e.
ini ial adhesi e o ces be ween he es ma e ials and he me al
o o , ollowed by a s eady s a e showing consis en ic ion o ces
conce ning ime o all h ee no mal load condi ions obse ed in
HF25P12, HF25P14, HF25P16, HF25P18, and HF25P22 as shown
in Figu es4A–E espec i ely. F ic ion o ce ends show a di ec
ela ion o he applied no mal loads. As e iden om hese igu es,
ic ion o ces inc eased wi h he inc ease in no mal loads. Mean
alues o SWR and COF we e plo ed a i e di e en load alues:
30N, 50N, 70N, 90N, and 110N, as shown in Figu e5,6,
espec i ely. The sliding eloci y was no conside ed in his case
becauseo i snegligiblein luenceon he esponsebeha io ,asshown
in Tables4,5.
Figu e5 shows highe Speci ic Wea Ra e (SWR) alues
o HF25P12 ollowed successi ely by HF25P14, HF25P16, and
HF25P18, and lowes o HF25P22. This migh be due o an
imp o ed pe cen age in he phenol o maldehyde esin, as a esul
o which imp o ed in e acial bonding be ween ib es and ma ix
migh ha e o med (Chand and Fahim, 2008). The d op in he
SWR wi h he ise in he no mal load om 30N o 110N is
expec ed, as seen o mos o he composi ions he e. This is
because, as pe equa ion (a), SWR is in e sely p opo ional o
he no mal load, and also, he wea ype a he ini ial s age is
likely o be adhesi e ype, which g adually changes o ab asi e
ype wi h an inc ease in he aspe i y con ac empe a u es a
he in e ace o he ic ion composi es and he me al coun e
ace (Ka hikeyane al., 2017). Fu he , i is obse ed ha beyond
90N load, SWR inc eases o HF25P22. This is a ibu ed o he
o e loading o he phenol- o maldehyde esin con en beyond he
sugges ed ange o 20–25% ol, which is app oxima ely 20–21%w .
o phenolic esins, as sugges ed in he ea ly epo ed li e a u e
(Blau, 2001).
In Figu e6, COF alues o HF25P12 a e highe , ollowed
successi ely by HF25P14, HF25P16, HF25P18, and lowes o
HF25P22. Also, all i e composi ions show a dec easing end wi h
he inc ease in he no mal load om 30N o 110N, ollowing he
ma hema ical ela ion shown in equa ion (b). This migh be due
o wo n su ace modi ica ion due o a ans e laye ha migh
ha e o med on he ic ion su ace. Also, he ise in aspe i y
con ac empe a u e a highe loads could be ano he possible eason
o he d op in COF (Chand and Fahim, 2008). Amongs hese
composi ions, HF25P22 shows lowe and mo e s able alues o
COF up o 90N, which migh be due o a highe pe cen age o
phenol o maldehyde esin making be e ibe –ma ix bonding
compa ed o i s coun e pa s s udied he e. Howe e , beyond 90N,
F on ie s in Ma e ials 07 on ie sin.o g
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FIGURE 4
(A) F ic ion o ce /s ime o HF25P12. (B) F ic ion o ce /s ime o HF25P14. (C) F ic ion o ce /s ime o HF25P16. (D) F ic ion o ce /s ime o
HF25P18. (E) F ic ion o ce /s ime o HF25P22.
TABLE 5 ANOVA o S/N a io o coe icien o ic ion.
Sou ce DOF Seq. SS Adj. SS Adj. MS F Value p-Value Con ibu ion (%)
Load 4 4.9054 4.9054 1.22634 8.56 0.002 31.95
Sliding eloci y 4 0.3479 0.3479 0.08698 0.61 0.665 2.27
Composi ion 4 8.3755 8.3755 2.09386 14.61 0.000 54.56
E o 12 1.7199 1.7199 0.14333 - -
To al 24 15.3487 - - - -
Seq. SS, sequen ial sum o squa es, Adj; SS, adjus ed sum o squa es, Adj; MS, adjus ed mean squa e.
F on ie s in Ma e ials 08 on ie sin.o g
Naidu e al. 10.3389/ ma s.2024.1348265
FIGURE 5
Va ia ion o speci ic wea a e (SWR) wi h espec o no mal load.
FIGURE 6
Va ia ion o coe icien o ic ion (COF) wi h espec o no mal load.
a ise in he COF alue is seen, which migh be due o he
o e loading o he PF con en beyond 20 %w . as epo ed by ea lie
li e a u e (Blau, 2001).
3.3 Analysis o a iance
Analysis o a iance (ANOVA) is a s a is ical p ocess o
acqui e he con ibu ion o composi ion, load, and eloci y in
he pe o mance cha ac e is ics iz SWR and COF. Tables4,5
show he SWR and COF’s ANOVA esul s, espec i ely. The
pe cen age con ibu ion o ac o s is he a io o he Sum o
Squa es o he ac o o he o al Sum o Squa es. Fo SWR,
composi ion plays he mos signi ican ole (59.66%), ollowed
by no mal load (33.15%) and inally by sliding eloci y o
he disc (2.90%).
Whe eas o COF, composi ion has highes con ibu ion
(54.56%), ollowed by he no mal load (31.95%) andlas ly he sliding
eloci y (2.27%).
TABLE 6 Op imum ac o s as pe main e ec plo s o S/N a io.
Pa ame e Load (N) Veloci y (m/s) Composi ion
SWR 110 5.2 HF25P22
COF 90 7.8 HF25P22
3.4 Op imiza ion o ac o s
The op imum le els sugges ed by Taguchi’s op imum design
o Speci ic Wea Ra e and Coe icien o F ic ion ac o s we e
ob ained om espec i e main e ec s plo s o S/N a ios. Figu e7,
8 ep esen op imum ac o le els o SWR and COF, espec i ely.
Figu e7 shows he composi ion o HF25P22, an applied load
o 110N, and a sliding eloci y o 5.2m/s as he combina ion
o op imum SWR. In con as , Figu e8 shows he composi ion
o HF25P22, an applied load o 90N, and a sliding eloci y o
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Naidu e al. 10.3389/ ma s.2024.1348265
FIGURE 16
(A–G) Fade eco e y pe o mance o HF25P22 ic ion composi e.
is essen ial o ensu ing he b ake pad can egain i s p e ious
ic ional pe o mance. Du ing his s age, HF25P20 success ully
eco e ed i s p e ious ic ion coe icien , which emained wi hin
he s anda d ange, as shown in Figu e15C. In con as , i was he
i s eco e y pe o mance o HF25P22, which showed a decline in
he eco e y cu e, as e iden in Figu e16C. Following he ini ial
h ee s ages, he wea beha io was assessed o e 100 pedaling
cycles a a ela i ely cons an empe a u e. As depic ed in Figu e15G
and 16G, he ic ion coe icien du ing he wea s age emained
wi hin he s anda d de ini ion ange, simila o he o he s ages.
The i s h ee s ages we e epea ed o con i m bo h b ake pads’
ic ion and wea p ope ies: a second baseline, a second ade, and
a second eco e y. Subsequen ly, he sample was weighed again,
esul ing in a loss o mass o 0.57gm. ou o an ini ial 4.710gm.
o HF25P20 and 0.66gm. ou o an ini ial 4.810gm o HF25P22.
Thus, he wea a e o HF25P22 was g ea e han HF25P20 by
1.62%. Acco ding o SAE J661 s anda ds, a b ake pad’s mass loss
a e unde going se en wea s ages should be below 1.230g, which
bo h HF25P20 and HF25P22 ha e obeyed. HF25P20 ecei ed a
classi ica ion o “GG” because he eco ded no mal and ho ic ion
coe icien alues we e 0.474 and 0.451, espec i ely, and HF25P22
ecei ed a classi ica ion o “GG,” as he eco ded no mal and ho
ic ion coe icien alues we e 0.493 and 0.452, as au oma ically
eco ded by he ic ion machine. The b ake ic ion pads o
comme cial ehicleswi hgood ic ion a high andlow empe a u es
usually belong o he “FF” classi ica ion and abo e (Ak ami a d
and Ghasemi, 2016).
4 Conclusion
Fi e di e en o mula ions we e c ea ed, each con aining
a ying pe cen ages o phenol o maldehyde esin, anging om
12% w . o 22% w . in 2% w . Inc emen s. The ic ion, wea , and
ade- eco e y pe o mance o he bes o he p esen ly o mula ed
ic ion composi e, namely, HF25P22, in compa ison o he au ho ’s
F on ie s in Ma e ials 16 on ie sin.o g

Naidu e al. 10.3389/ ma s.2024.1348265
ea lie bes - epo ed HF25P20 (HF6P20) ic ion composi e, e eals
he ollowing:
• The SWR a oom empe a u e o HF25P20 is less han ha o
HF25P22 by nea ly 6%. A lowe SWR is usually desi ed o any
good ic ion ma e ial.
• The ac ual (op imized) COF o HF25P20 and HF25P22 a oom
empe a u e a e 0.4496 and 0.4650, espec i ely, which a e in
line wi h hose du ing he ade and eco e y s ages o he same,
espec i ely and also wi hin he ecommended limi s o 0.3–0.5
o comme cial ehicles as pe SAE J661 s anda ds.
• The ade eco e y o HF25P20 is be e han ha o HF25P22.
• HF25P20 and HF25P22 ha e been a ed wi h he “GG”
ic ion ma e ial by SAE J661 s anda ds, which a e sui able o
comme cial au omo i e applica ions.
• Thus, he b ake ic ion composi e, namely, HF25P20, which
was in es iga ed and epo ed by he au ho s ea lie as HF6P20,
s ill p o ed o be a be e -pe o ming b ake ic ion ma e ial
han all i s coun e pa s, which a e s udied and epo ed in he
p esen explo a ion.
This s udy hus shows con i ma ion o ea lie epo ed
pe cen age o phenol o maldehyde esin con en (Blau, 2001)
(20%–21% w .) which is also ue o hemp (na u al) ib e ein o ced
b ake ic ion ma e ials.
Howe e , u u e explo a ions on he use o na u al esins like
s a ch, p o eins, na u al gums, e c. as binde s in ic ion ma e ials
needs a en ion, in o de o p o ide s ill be e g eene al e na i es
o exis ing comme cial b ake ic ion ma e ials.
Da a a ailabili y s a emen
The o iginal con ibu ions p esen ed in he s udy a e included in
he a icle/Supplemen a y ma e ial, u he inqui ies can be di ec ed
o he co esponding au ho s.
Au ho con ibu ions
MN: Concep ualiza ion, Da a cu a ion, Me hodology, P ojec
adminis a ion, Resou ces, W i ing–o iginal d a , W i ing– e iew
and edi ing. AB: Fo mal Analysis, In es iga ion, Me hodology,
P ojec adminis a ion, Resou ces, Supe ision, W i ing– e iew
and edi ing. MG: Da a cu a ion, Fo mal Analysis, In es iga ion,
P ojec adminis a ion, Resou ces, W i ing– e iew and edi ing. SS:
In es iga ion, P ojec adminis a ion, Supe ision, Visualiza ion,
W i ing– e iew and edi ing. RC: In es iga ion, Me hodology,
P ojec adminis a ion, Resou ces, W i ing– e iew and edi ing.
EA: Da a cu a ion, Funding acquisi ion, In es iga ion, P ojec
adminis a ion, Resou ces, W i ing– e iew and edi ing.
Funding
The au ho (s) decla e inancial suppo was ecei ed o he
esea ch, au ho ship, and/o publica ion o his a icle. The au ho s
also hank King Saud Uni e si y o unding his wo k h ough
Resea che s Suppo ing P ojec numbe (RSP2024R164), King Saud
Uni e si y, Riyadh, Saudi A abia.
Acknowledgmen s
The au ho s exp ess hei hanks o MKSSS’s Cummins
College o Enginee ing o Women, Pune, o p o iding hei
composi e ma e ial p ocessing acili y o Composi e Ma e ial
Labo a o y Sponso ed by AICTE MODROB Scheme (9-
166/RFID/MODROB/Policy-1/2017-18) o his wo k. The au ho s
hank King Saud Uni e si y o unding his wo k h ough he
Resea che s Suppo ing P ojec numbe (RSP2024R164), King Saud
Uni e si y, Riyadh, Saudi A abia.
Con lic o in e es
The au ho s decla e ha he esea ch was conduc ed in he
absence o any comme cial o inancial ela ionships ha could be
cons ued as a po en ial con lic o in e es .
Publishe ’s no e
All claims exp essed in his a icle a e solely hose o he
au ho s and do no necessa ily ep esen hose o hei a ilia ed
o ganiza ions, o hose o he publishe , he edi o s and he
e iewe s. Any p oduc ha may be e alua ed in his a icle, o claim
ha may be made by i s manu ac u e , is no gua an eed o endo sed
by he publishe .
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