applied
sciences
A icle
E ec o Ha sh En i onmen al Condi ions on he Impac
Response o Ca bon Composi es wi h Filled Ma ix by
Co k Powde
Ma co P. Sil a 1,* , Paulo San os 1, João Pa en e 1, Sa a Val ez 1and Paulo N. B. Reis 2


Ci a ion: Sil a, M.P.; San os, P.;
Pa en e, J.; Val ez, S.; Reis, P.N.B.
E ec o Ha sh En i onmen al
Condi ions on he Impac Response
o Ca bon Composi es wi h Filled
Ma ix by Co k Powde . Appl. Sci.
2021,11, 7436. h ps://doi.o g/
10.3390/app11167436
Academic Edi o : Valen ino
Paolo Be a di
Recei ed: 15 July 2021
Accep ed: 9 Augus 2021
Published: 12 Augus 2021
Publishe ’s No e: MDPI s ays neu al
wi h ega d o ju isdic ional claims in
published maps and ins i u ional a il-
ia ions.
Copy igh : © 2021 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license (h ps://
c ea i ecommons.o g/licenses/by/
4.0/).
1C-MAST, Depa men o Elec omechanical Enginee ing, Uni e si y o Bei a In e io , Calçada Fon e do
Lamei o, 6201-100 Co ilhã, Po ugal; paulo.se [email p o ec ed] (P.S.); [email p o ec ed] (J.P.);
[email p o ec ed] (S.V.)
2CEMMPRE, Depa men o Mechanical Enginee ing, Uni e si y o Coimb a, 3030-788 Coimb a, Po ugal;
[email p o ec ed]
*Co espondence: ma [email p o ec ed]
Abs ac :
Composi es a e used in a wide ange o enginee ing applica ions, as a esul , exposu e o
hos ile en i onmen s is a he common and i s mechanical p ope ies deg ada ion is una oidable. I
is necessa y o ha e a comple e unde s anding o he impac o hos ile en i onmen s on mechanical
pe o mance, namely c i ical solici a ions as low eloci y impac s. The e o e, his wo k in ends
o analyse he low eloci y impac esponse o a ca bon ib e/epoxy composi e, and a simila
a chi ec u e wi h an epoxy ma ix illed wi h co k, a e imme sion in o di e en solu ions: diesel,
H
2
SO
4
, HCl, NaOH, dis illed wa e , seawa e , and seawa e a 60
◦
C. These solu ions signi ican ly
a ec ed he impac p ope ies. In his con ex , he maximum load, maximum displacemen , and
es o ed ene gy beha iou we e s udied o unde s and he in luence o exposu e ime. I was possible
o conclude ha such impac pa ame e s we e signi ican ly a ec ed by he solu ions, whe e he
exposu e ime p o ed o be de e minan . The bene i s o co k on he pe o a ion h eshold we e
in es iga ed, and his pa ame e inc eased when he epoxy ma ix was illed wi h co k. Finally,
co k illed epoxy lamina es also show less a ia ion in maximum load and eco e ed ene gy han
ca bon/epoxy lamina es.
Keywo ds: composi e lamina es; hos ile solu ions; expe imen al es s; low eloci y impac
1. In oduc ion
Fib e- ein o ced composi es ha e been used in a a ie y o enginee ing ields such
as ai c a , space, au omo i e, spo , ma ine indus ies, and mili a y applica ions due o
hei excellen pe o mance in e ms o high speci ic s eng h and s i ness, good s a ic and
dynamic p ope ies, good co osion esis ance, adjus able p ope ies, compe i i e cos , and
as manu ac u e [
1
–
4
]. Ca bon ib es, o example, ha e g ea s eng h and ha dness, as
well as excellen empe a u e esis ance, chemical esis ance, and low he mal expansion.
They a e ideal candida es o use in he ae ospace/ae onau ical, au omo i e, cons uc ion,
mili a y, and spo s indus ies due o hei ad an ages [1,3,5–9].
Nume ous s udies ha e been conduc ed o inc ease in e acial adhesion wi h he
ma ix [
10
–
14
], as a consequence o he low su ace ene gy and chemically ine su ace o
some ib es. On he o he hand, li e a u e epo s ha he addi ion o low concen a ions o
nanopa icles o he ma ix is an excellen solu ion o imp o e he mechanical pe o mance
o composi e lamina es wi hou comp omising hei densi y, oughness o manu ac u -
ing p ocess [
4
,
15
,
16
]. Nowadays, o easons o en i onmen al sus ainabili y, composi es
inco po a ing na u al ein o cemen s ha e gained popula i y due o hei low densi y,
abundance, ab asi eness du ing p ocessing, low cos , enewable, and biodeg adable p op-
e ies [
17
]. In his con ex , co k has unique cha ac e is ics, and i s powde , which is a
by-p oduc o ag icul u e, is a iable op ion o use in polyme ic composi es. Fo example,
Appl. Sci. 2021,11, 7436. h ps://doi.o g/10.3390/app11167436 h ps://www.mdpi.com/jou nal/applsci
Appl. Sci. 2021,11, 7436 2 o 17
li e a u e epo s ha , compa ed o lamina es wi h nea ma ices, polyme composi es
con aining co k powde ha e highe abso bed impac ene gy and glass ansi ion empe a-
u e, p omo e less damage a eas and ha e he bes elas ic eco e y pe o mance. A he
same ime, i became clea ha co k powde inc eases he pene a ion
h eshold [17–19]
.
The e o e, high ole ance o damage om impac loads, wea and i e esis ance, low
he mal conduc i i y, and excellen damping a e impo an cha ac e is ics o he use o
co k in composi es used in ha sh en i onmen s [20–23].
The open li e a u e epo s se e al s udies on he e ec o hos ile en i onmen s on
he mechanical p ope ies o composi e ma e ials. Fo example, he e ec s o alkaline
(NaOH) and acid (HCl) solu ions in ib e- ein o ced polyme composi es we e s udied
by Ama o e al. [
24
] and, acco ding o he au ho s, alkaline solu ions p o ed o be mo e
ha m ul han acid solu ions, esul ing in lowe lexu al s eng h and modulus. Ano he
s udy showed ha lexu al s eng h is insensi i e up o 30 days a e imme sion in HCl,
a e which he e is a 10% dec ease [
25
]. Kawada and S i as a a [
26
] s udied he exposu e
o a composi e lamina e o a co osi e en i onmen and obse ed ha sha p c acks begin
o de elop and sp ead when he acid weakens he ib es, esul ing in e y low s eng h
and highly la ac u e wi h low ailu e s ess. The esins used as ma ix in lamina ed
composi es, acco ding o Banna e al. [
27
], ha e a conside able in luence on he inal
mechanical pe o mance. When subjec ed o highe empe a u es o o longe pe iods o
ime, au ho s conclude ha polyes e esin has a lowe modulus han bisphenol A epoxy
inyl es e . Due o he impo ance o he ma ix o he composi e s uc u al in eg i y, he
epoxy esin’s abili y o deal wi h p og essi ely ad e se condi ions will de e mine he
composi e’s sui abili y o speci ic applica ions [27].
Acco ding o he li e a u e, composi e lamina es a e s ong in he in-plane loading
di ec ion, bu e y weak in he ou -o -plane loading di ec ion [
28
]. Impac damage is
belie ed o be he main sou ce o composi e delamina ion in se ice, which is qui e dan-
ge ous because i signi ican ly a ec s he pe o mance o hese ma e ials [
8
,
9
,
29
] and,
simul aneously, is di icul o iden i y isually [
30
]. Howe e , he e is a lack o esea ch
ha inco po a es impac loads and ha sh en i onmen al condi ions, in pa icula in ol ing
composi es ein o ced wi h co k. The e o e, he main goal o his wo k is o in es iga e
he bene i o co k powde on low eloci y impac s eng h in ca bon/epoxy composi es
a e imme sion in o hyd ochlo ic acid (HCl), sodium hyd oxide (NaOH), sulphu ic acid
(H2SO4), diesel, dis illed wa e , and seawa e .
2. Ma e ial and Expe imen al P ocedu e
Nine ply lamina es o ca bon ib e bidi ec ional plain wea e ab ic ( a e a wea e wi h
160 g/cm
2
), all in he same di ec ion, and an Amp eg 22 epoxy esin wi h an Amp eg 22
ha dene s anda d, bo h supplied by Gu i , we e used o p oduce composi e lamina es.
Pla es wi h o e all dimensions o 330
×
330
×
2.4
±
0.1 (mm
3
) we e p oduced by he
hand lay-up p ocess. This sys em was placed inside a acuum bag and a load o 2.5 kN
was applied o 48 h o main ain a cons an ib e olume ac ion and a uni o m lamina e
hickness. Du ing he i s 10 h he bag emained a ached o a acuum pump o elimina e
any ai bubbles exis ing in he composi e. The pos -cu e was ca ied ou in an o en a
45 ◦C o 48 h.
Using he same manu ac u ing p ocess, composi e lamina es wi h epoxy ma ix illed
wi h co k powde we e also p oduced. The bulk densi y o he co k powde used is
abou 0.11 g
·
cm
−3
and he pa icles’ size, in e ms o pe cen ile, is d(0.1) = 18.6
µ
m,
d(0.5) = 78.9 µm
and d(0.9) = 208.3
µ
m. Mo e de ails can be ound in [
17
]. The co k powde
was d ied in an o en (He aus, model UT 6060) a abou 120
◦
C du ing 2 h and d ied in
a desicca o un il use. Epoxy esin and co k powde we e mixed a 900 pm o 2 h and,
a same ime, subjec ed o ul asonic ba h sonica o . Finally, he mix u e was degassed
in a acuum o en, ollowed by addi ion o he ha dene wi h special ca e o a oid he
p esence o ai bubbles. The ille con en was 3 w .% o he epoxy esin-ha dene mix u e
as epo ed in [19].
Appl. Sci. 2021,11, 7436 3 o 17
The samples used in his s udy we e cu om hese pla es o squa e specimens wi h
100 mm side, which we e comple ely subme ged in o di e en solu ions and di e en
imme sion imes, bo h summa ized in Table 1. All solu ions ha e a concen a ion o 10%
by weigh (w .%), which co esponds o a pH o 13.0 o NaOH and 1.5 o acids. Excep
o seawa e a 60
◦
C, all he o he solu ions in which he specimens we e imme sed a e
a oom empe a u e. Finally, he samples we e washed wi h clean wa e and d ied a
oom empe a u e.
Table 1. Di e en solu ions and imme sion imes used in his s udy.
Solu ions Imme sion Time (Days)
Diesel 15, 30 and 45
Sulphu ic acid (H2SO4), pH = 1.5 10, 20 and 30
Hyd ochlo ic acid (HCl), pH = 1.5 10, 20 and 30
Sodium hyd oxide (NaOH), pH = 13.0 10, 20 and 30
Dis illed wa e 15, 30, 60 and 90
Seawa e a oom empe a u e 15, 30, 60 and 90
Seawa e a 60 ◦C 15, 30 and 45
Low- eloci y impac es s we e pe o med using a d op weigh es ing machine
IMATEK-IM10. Mo e de ails o he impac machine can be ound in [
31
]. An impac o
diame e o 20 mm wi h a mass o 3.005 kg was used. The es s we e pe o med on squa e
sec ion samples o dimensions 75
×
75 mm and he impac o s oke a he cen e o he
samples ob ained by cen ally suppo ing he 100
×
100 mm specimens. Impac ene gies
o 2, 4, 8, 10, 12, 16, 20 and 24 J we e used o analyse he impac s eng h and he e ec o
co k powde on he impac s eng h. The e ec o hos ile solu ions on he impac s eng h
was e alua ed o he ene gy o 12 J. Fo each condi ion/en i onmen , i e specimens we e
es ed, and he esul s p esen ed in e ms o a e age alues.
3. Resul s
The bene i s ob ained wi h co k powde we e e alua ed by impac es s ca ied ou
o di e en impac ene gies. Figu e 1shows ypical load and ene gy e sus ime cu es
o con ol samples and lamina es wi h esin illed wi h 3% o co k powde es ed o an
impac ene gy o 2 J.
Figu e 1. Fo an impac ene gy o 2 J, ypical: (a) load e sus ime cu es; (b) ene gy e sus ime cu es.
Appl. Sci. 2021,11, 7436 4 o 17
Bo h cu es shown in Figu e 1 ep esen he ypical p o ile o all es s and a e in good
ag eemen wi h he li e a u e [
8
,
32
–
34
]. The oscilla ions in he load-displacemen cu es
(Figu e 1a) a e caused by he elas ic wa e and he ib a ions o he samples [
35
]. In de ail,
he load-displacemen cu es show ha he load ises un il i eaches a maximum alue,
and hen d ops ab up ly a e eaching i s maximum alue. A non-pe o a ing impac was
iden i ied because he impac ene gy was insu icien o comple ely pene a e he sample.
In ac , he impac o s uck in o he sample and always ebounded. The e o e, he beginning
o he pla eau in he ene gy- ime cu es (Figu e 1b) co esponds o he loss o con ac
be ween he s ike and he specimen [
19
,
36
], so his ene gy is he one abso bed by he
specimen. Finally, in bo h igu es i is possible o obse e he in luence o he esin illed
wi h co k powde on he impac beha iou o he composi e. Fo example, Figu e 1a shows
an inc ease in displacemen wi h he p esence o co k powde , while Figu e 1b shows less
abso bed ene gy and longe con ac ime.
In de ail, he e ec o he co k powde is shown in Figu e 2in e ms o maximum load,
maximum displacemen , and es o ed ene gy o all impac ene gies. Symbols ep esen
a e age alues. This igu e shows how hese pa ame e s e ol e wi h impac ene gy, while
Table 2summa izes all a e age alues and hei espec i e s a is ical a ia ions in e ms o
s anda d de ia ion.
Figu e 2. Fo di e en impac ene gies: (a) maximum load, (b) maximum displacemen , (c) es o ed ene gy.
Table 2. Summa y o all pa ame e s ob ained om he impac es s and espec i e s anda d de ia ion.
Impac Ene gy (J) Maximum Load (kN) Maximum Load (mm) Con ac Time (ms) Res o ed Ene gy (%)
A e age S d De A e age S d De A e age S d De A e age S d De
Ca bon Lamina es
2 1.56 0.21 3.0 0.3 7.24 0.29 60.8 2.1
4 2.29 0.18 3.3 0.5 7.07 0.46 48.5 2.3
8 2.67 0.20 5.4 0.3 7.73 0.35 28.6 1.4
10 2.82 0.22 5.7 0.6 7.93 0.36 24.3 1.9
12 3.16 0.23 6.6 0.3 8.04 0.31 21.4 1.2
16 3.12 0.19 9.0 0.3 8.55 0.35 17.8 1.6
20 2.93 0.17 10.6 0.7 9.77 0.64 15.1 1.3
24 3.21 0.24 11.9 0.4 10.49 0.67 13.9 1.1
Ca bon Lamina es wi h Co k
2 1.56 0.21 3.0 0.2 7.55 0.32 64.2 3.2
4 1.89 0.23 4.5 0.2 8.51 0.29 31.0 3.9
8 2.22 0.19 6.6 0.3 9.31 0.37 20.7 3.5
10 2.27 0.22 7.8 0.3 10.38 0.24 19.1 2.7
12 2.44 0.19 8.8 0.5 10.17 0.43 16.6 2.8
16 2.27 0.17 10.8 0.6 10.95 0.39 14.4 3.6
20 2.44 0.19 12.8 0.2 11.89 0.31 12.2 3.1
24 2.41 0.24 17.2 0.3 15.68 0.37 10.3 3.0
Appl. Sci. 2021,11, 7436 5 o 17
Rega ding he maximum load (Figu e 2a and Table 2), and ega dless o he impac
ene gy, i is possible o obse e highe alues o composi es wi h nea esin han o
composi es wi h esin illed wi h co k powde . On he o he hand, o bo h lamina es,
highe impac ene gies p omo ed highe maximum loads up o 12 J, a e which he
maximum impac load seems o emain cons an . While he maximum load inc eased
a ound 56.4% be ween 2 J and 12 J o composi es wi h co k powde , his alue was abou
102.6% (a ound wice highe ) o composi e lamina es wi h nea esin.
In ac , li e a u e epo s ha he maximum load inc eases wi h inc easing impac
ene gy [
16
,
19
,
31
,
37
], and his end can be obse ed in his s udy up o 12 J o bo h
lamina es. Acco ding o Gus in e al. [
38
] he di e ences obse ed in he maximum loads
a e a consequence o he di e en ailu e modes in oduced in he lamina e and, in his
con ex , i is possible o no e ha o impac ene gies highe han 12 J he se e i y o he
damage is so signi ican ha he e ec is no isible in e ms o maximum load. Simila
beha iou was obse ed by Reis e al. [
37
], as well as he non-linea i y also obse ed in
Figu e 2a and ha acco ding o Hosu e al. [
39
], he maximum load should inc ease almos
linea ly wi h he inc ease o he impac ene gy. This pa ame e is con olled by he impac
ene gy and e lec s he maximum load ha he composi e lamina e can ole a e be o e
se e e damage occu s [37].
The bene i s ob ained wi h he co k powde and espec i e in luence o impac ene gy
on he displacemen is shown in Figu e 2b and Table 2. Independen ly o he impac ene gy,
he a e age esul s show ha lamina es wi h co k powde ha e he highes displacemen s.
Fo he s udied ene gy ange, o example, displacemen s inc eased a ound 298% and 476%
o lamina es wi h nea esin and lamina es wi h epoxy illed by co k powde , espec i ely.
Consequen ly, as shown in Table 2, he con ac ime is highe o lamina es wi h co k
powde . Unde comp essi e loading du ing he impac , when co k de o ms, he cell
walls bend and buckle and can unde go la ge s ain de o ma ion. The e o e, his explains
he highe displacemen s and he lowes maximum loads obse ed in composi es ha
inco po a e co k powde . On he o he hand, when cell walls bend and buckle, hey can
abso b la ge amoun s o ene gy wi h high iscoelas ic e u n. This means ha , a e an
impac , he capaci y o he co k o con inue o abso b ene gy is almos unchanged due o
i s elas ic de o ma ion [
40
,
41
]. The bene i s epo ed a e exp essed in Figu e 2c, whe e he
lowe es o ed ene gy o lamina es wi h co k powde is a consequence o he highe ene gy
abso p ion capaci y. Fo ca bon/epoxy lamina es, i is possible o obse e a dec ease in
he elas ic eco e y a ound 53%, be ween 2 and 8 J, bu his alue d ops d as ically o 77%
be ween 2 and 24 J. When he co k powde is added o he esin, he beha iou is simila ,
bu in his case wi h alues a ound 68% and 84%, espec i ely.
F om Figu e 2c i is possible o obse e ha he elas ic ene gy is ne e equal o ze o,
which means ha he abso bed ene gy is ne e equal o he impac ene gy. The e o e, he
pene a ion h eshold was no eached because he excess ene gy is used o ebound he im-
pac o [
42
,
43
]. In his con ex , i he elas ic ene gy e sus impac ene gy is plo ed and he
da a i ed by polynomial equa ions, he pene a ion h esholds can be
de e mined [19,43]
.
Figu e 3shows he me hodology used o ob ain he pene a ion h eshold o all lami-
na es, and alues o 34.5 J and 37.6 J we e ound o con ol lamina es and co k- illed
lamina es, espec i ely.

Appl. Sci. 2021,11, 7436 6 o 17
Figu e 3. Pene a ion h eshold o lamina es wi h nea esin and ma ix illed wi h co k powde .
The e ec o hos ile solu ions on he impac s eng h was e alua ed o he ene gy
o 12 J. Fo each condi ion, i e specimens we e used, and he esul s p esen ed in e ms
o a e age alues. The in luence o he exposu e ime on he maximum load, maximum
displacemen and es o ed ene gy we e analysed and he esul s shown in
Figu es 4–6
,
espec i ely. In hese ep esen a ions, each esul was dimensionless/di ided by he espec-
i e alue ob ained wi h he con ol specimens (wi hou imme sion in any solu ion). The
a e age esul s and espec i e s anda d de ia ions will be summa ized in o m
o ables.
The e o e. he bene i achie ed wi h he in oduc ion o co k powde in he esin
is no o ious, which p omo es an inc ease in he pene a ion h eshold abou 9% highe
han ha o he con ol samples. This is a consequence o he signi ican amoun o ene gy
abso bed by co k associa ed wi h he high iscoelas ic e u n [
40
,
41
]. A simila bene i
was ob ained by Reis e al. [
19
] o Ke la lamina es, when he epoxy ma ix was illed
wi h co k powde . In his case, he pene a ion h eshold was a ound 30.9 J o he con ol
samples, while o lamina es wi h co k powde his alue was abou 34.8 J, p omo ing, in
his case, a bene i a ound 12.6%. Howe e , he g ea es bene i obse ed by he au ho s in
ela ion o ha ob ained in he p esen s udy is due o Ke la ib es being mo e ole an o
damage han ca bon ib es.
Figu e 4. Con .
Appl. Sci. 2021,11, 7436 7 o 17
Figu e 4.
In luence o solu ion ype and exposu e ime on he maximum impac load a e imme sion in o: (
a
) diesel;
(b) H2SO4, (c) HCl, (d) NaOH, (e) dis illed wa e and seawa e ; ( ) seawa e a oom empe a u e and a 60 ◦C.
Figu e 5. Con .
Appl. Sci. 2021,11, 7436 8 o 17
Figu e 5.
In luence o solu ion on he displacemen a e imme sion in o: (
a
) diesel; (
b
) H
2
SO
4
, (
c
) HCl, (
d
) NaOH,
(e) dis illed wa e and seawa e ; ( ) seawa e a oom empe a u e and a 60 ◦C.
Figu e 6. Con .
Appl. Sci. 2021,11, 7436 9 o 17
Figu e 6.
In luence o solu ion ype and exposu e ime on he es o ed ene gy a e imme sion in o: (
a
) diesel; (
b
) H
2
SO
4
,
(c) HCl, (d) NaOH, (e) dis illed wa e and seawa e ; ( ) seawa e a oom empe a u e and a 60 ◦C.
F om Figu e 4, i is possible o obse e ha , o all ha sh en i onmen s, lamina es
wi h nea esin a e much mo e sensi i e o exposu e o such solu ions han ca bon lam-
ina es wi h ma ix illed wi h co k. I is also no iced ha he maximum load dec eases
when he samples a e exposed o di e en en i onmen s and his endency is highly de-
penden on he exposu e ime. This e idence ag ees wi h he s udies epo ed in he
open
li e a u e [24,44,45]
. Al hough he alues a e always lowe han hose obse ed in
specimens no exposed o hos ile en i onmen s, Table 3also shows ha he beha iou o
lamina es wi h ma ix illed wi h co k powde always e ealed a maximum impac load
lowe han ha obse ed in con ol lamina es.
Fo example, compa ing he maximum impac load ob ained o 30 days o imme sion
in o di e en solu ions and he alue ob ained o he espec i e lamina es wi hou any
deg ada ion (no imme sion in such solu ions), i is possible o assess he se e i y o
ha sh en i onmen s in his pa ame e (maximum impac load). This e ec is summa ized
in Table 4, in which he dec ease obse ed o he di e en solu ions is p esen ed in
pe cen age e ms.
Appl. Sci. 2021,11, 7436 16 o 17
16.
Iqbal, K.; Khan, S.U.; Muni , A.; Kim, J.K. Impac damage esis ance o CFRP wi h nanoclay- illed epoxy ma ix. Compos. Sci.
Technol. 2009,69, 1949–1957. [C ossRe ]
17.
Reis, P.N.B.; Fe ei a, J.A.M.; Sil a, P.A.A. Mechanical beha iou o composi es illed by ag o-was e ma e ials. Fibe s Polym.
2011
,
12, 240–246. [C ossRe ]
18.
Reis, P.N.B.; Fe ei a, J.A.M.; Cos a, J.D.M.; San os, M.J. Fa igue pe o mance o Ke la /epoxy composi es wi h illed ma ix by
co k powde . Fibe s Polym. 2012,13, 1292–1299. [C ossRe ]
19.
Reis, P.N.B.; Fe ei a, J.A.M.; San os, P.; Richa dson, M.O.W.; San os, J.B. Impac esponse o Ke la composi es wi h illed epoxy
ma ix. Compos. S uc . 2012,94, 3520–3528. [C ossRe ]
20. Rosa, M.; Fo es, M. De o ma ion and ac u e o co k in ension. J. Ma e . Sci. 1991,26, 341–348. [C ossRe ]
21. Rosa, M.E.; Fo es, M. Wa e abso p ion by co k. Wood Fibe Sci. 1993,25, 339–348.
22. Mano, J.F. The iscoelas ic p ope ies o co k. J. Ma e . Sci. 2002,37, 257–263. [C ossRe ]
23.
Sil a, S.P.; Sabino, M.A.; Fe nandes, E.M.; Co elo, V.M.; Boesel, L.F.; Reis, R.L. Co k: P ope ies, capabili ies and applica ions. In .
Ma e . Re . 2005,50, 345–365. [C ossRe ]
24.
Ama o, A.M.; Reis, P.N.B.; Ne o, M.A.; Lou o, C. E ec s o alkaline and acid solu ions on glass/epoxy composi es. Polym. Deg ad.
S ab. 2013,98, 853–862. [C ossRe ]
25.
Mahmoud, M.K.; Tan awi, S.H. E ec o s ong acids on mechanical p ope ies o glass/polyes e GRP pipe a no mal and high
empe a u es. Polym. Plas . Technol. Eng. 2003,42, 677–688. [C ossRe ]
26.
Kawada, H.; S i as a a, V.K. The e ec o an acidic s ess en i onmen on he s ess-in ensi y ac o o GRP lamina es. Compos.
Sci. Technol. 2001,61, 1109–1114. [C ossRe ]
27.
Banna, M.H.; Shi oko , J.; Molgaa d, J. E ec s o wo aqueous acidic solu ions on polyes e and bisphenol A epoxy inyl es e
esins. Ma e . Sci. Eng. A 2011,528, 2137–2142. [C ossRe ]
28.
Richa dson, M.; Wishea , M. Re iew o low- eloci y impac p ope ies o composi e ma e ials. Compos. Pa A Appl. Sci. Manu .
1996,27, 1123–1131. [C ossRe ]
29.
Ama o, A.M.; Reis, P.N.; De Mou a, M.F. Residual s eng h a e low eloci y impac in ca bon-epoxy lamina es. In Ma e ials
Science Fo um; T ans Tech Publ.: S a a-Zu ich, Swi ze land, 2006; Volume 514, pp. 624–628.
30.
Ama o, A.M.; Reis, P.N.B.; De Mou a, M.F.S.F.; San os, J.B. Damage de ec ion on lamina ed composi e ma e ials using se e al
NDT echniques. Insigh -Non-Des . Tes . Cond. Moni . 2012,54, 14–20. [C ossRe ]
31.
Ama o, A.M.; Reis, P.N.B.; Magalhães, A.G.; De Mou a, M.F.S.F. The in luence o he bounda y condi ions on low- eloci y impac
composi e damage. S ain 2011,47, e220–e226. [C ossRe ]
32.
Hosu , M.; Adbullah, M.; Jeelani, S. S udies on he low- eloci y impac esponse o wo en hyb id composi es. Compos. S uc .
2005,67, 253–262. [C ossRe ]
33.
Ama o, A.M.; Reis, P.N.B.; De Mou a, M.F.S.F.; Ne o, M.A. In luence o mul i-impac s on GFRP composi es lamina es. Compos.
Pa B Eng. 2013,52, 93–99. [C ossRe ]
34.
Reis, P.N.B.; Fe ei a, J.A.M.; Zhang, Z.Y.; Benameu , T.; Richa dson, M.O.W. Impac esponse o Ke la composi es wi h nanoclay
enhanced epoxy ma ix. Compos. Pa B Eng. 2013,46, 7–14. [C ossRe ]
35.
Schoeppne , G.A.; Ab a e, S. Delamina ion h eshold loads o low eloci y impac on composi e lamina es. Compos. Pa A Appl.
Sci. Manu . 2000,31, 903–915. [C ossRe ]
36.
Gómez-del Rıo, T.; Zae a, R.; Ba be o, E.; Na a o, C. Damage in CFRPs due o low eloci y impac a low empe a u e. Compos.
Pa B Eng. 2005,36, 41–50. [C ossRe ]
37.
Reis, P.N.B.; San os, P.; Fe ei a, J.A.M.; Richa dson, M.O.W. Impac esponse o sandwich composi es wi h nano-enhanced epoxy
esin. J. Rein . Plas . Compos. 2013,32, 898–906. [C ossRe ]
38.
Gus in, J.; Joneson, A.; Mahin alah, M.; S one, J. Low eloci y impac o combina ion Ke la /ca bon ibe sandwich composi es.
Compos. S uc . 2005,69, 396–406. [C ossRe ]
39.
Hosu , M.V.; Chowdhu y, F.; Jeelani, S. Low-Veloci y Impac Response and Ul asonic NDE o Wo en Ca bon/Epoxy—Nanoclay
Nanocomposi es. J. Compos. Ma e . 2007,41, 2195–2212. [C ossRe ]
40.
Fe nandes, F.A.O.; Pascoal, R.J.S.; Al es de Sousa, R.J. Modelling impac esponse o agglome a ed co k. Ma e . Des.
2014
,58,
499–507. [C ossRe ]
41.
Oli ei a, V.; Rosa, M.E.; Pe ei a, E. Va iabili y o he comp ession p ope ies o co k. Wood Sci. Technol.
2014
,48, 937–948.
[C ossRe ]
42.
Shim, V.P.W.; Tan, V.B.C.; Tay, T.E. Modelling de o ma ion and damage cha ac e is ics o wo en ab ic unde small p ojec ile
impac . In . J. Impac Eng. 1995,16, 585–605. [C ossRe ]
43.
Ak a¸s, M.; A as, C.; ˙
Iç en, B.M.; Ka akuzu, R. An expe imen al in es iga ion o he impac esponse o composi e lamina es.
Compos. S uc . 2009,87, 307–313. [C ossRe ]
44.
Ama o, A.M.; Reis, P.N.B.; Ne o, M.A.; Lou o, C. E ec o di e en acid solu ions on glass/epoxy composi es. J. Rein . Plas .
Compos. 2013,32, 1018–1029. [C ossRe ]
45.
Mo as, N.; E , O.; Reis, P.N.B.; Fe ei a, J.A.M. E ec o co osi e solu ions on composi es lamina es subjec ed o low eloci y
impac loading. Compos. S uc . 2014,108, 205–211. [C ossRe ]
46.
A un, K.V.; Basa a ajappa, S.; She iga a, B.S. Damage cha ac e isa ion o glass/ ex ile ab ic polyme hyb id composi es in sea
wa e en i onmen . Ma e . Des. 2010,31, 930–939. [C ossRe ]

Appl. Sci. 2021,11, 7436 17 o 17
47.
S ameno i´c, M.; Pu i´c, S.; Rakin, M.; Medjo, B.; ˇ
Cika a, D. E ec o alkaline and acidic solu ions on he ensile p ope ies o
glass–polyes e pipes. Ma e . Des. 2011,32, 2456–2461. [C ossRe ]
48.
Ray, B.C. Tempe a u e e ec du ing humid ageing on in e aces o glass and ca bon ibe s ein o ced epoxy composi es. J. Colloid
In e ace Sci. 2006,298, 111–117. [C ossRe ]
49.
Abdel-Magid, B.; Ziaee, S.; Gass, K.; Schneide , M. The combined e ec s o load, mois u e and empe a u e on he p ope ies o
E-glass/epoxy composi es. Compos. S uc . 2005,71, 320–326. [C ossRe ]
50.
Pa an, A.; Dayananda, P.; Vijaya, K.M.; Hegde, S.; Hosagade, P.N. In luence o seawa e abso p ion on ib a ional and ensile
cha ac e is ics o quasi-iso opic glass/epoxy composi es. J. Ma e . Res. Technol. 2019,8, 1427–1433. [C ossRe ]
51.
Ga gano, A.; Pingka awa , K.; Picke d, V.; Delaney, T.; Das, R.; Mou i z, A.P. E ec o seawa e imme sion on he explosi e blas
esponse o a ca bon ib e-polyme lamina e. Compos. Pa A Appl. Sci. Manu . 2018,109, 382–391. [C ossRe ]
52.
Tual, N.; Ca e e, N.; Da ies, P.; Bonnemains, T.; Loli e, E. Cha ac e iza ion o sea wa e ageing e ec s on mechanical p ope ies
o ca bon/epoxy composi es o idal u bine blades. Compos. Pa A Appl. Sci. Manu . 2015,78, 380–389. [C ossRe ]
53.
Boisseau, A.; Pey ac, C. Long e m du abili y o composi es in ma ine en i onmen : Compa a i e s udy o a igue beha io .
P ocedia Eng. 2015,133, 535–544. [C ossRe ]
54.
Ka odya, I.; Xian, G.; Li, H. Du abili y s udy o pul uded CFRP pla es imme sed in wa e and seawa e unde sus ained bending:
Wa e up ake and e ec s on he mechanical p ope ies. Compos. Pa B Eng. 2015,70, 138–148. [C ossRe ]
55.
Jes hi, D.K.; Nayak, R.K. Imp o emen o mechanical p ope ies o hyb id composi es h ough in e ply ea angemen o glass
and ca bon wo en ab ics o ma ine applica ion. Compos. Pa B Eng. 2019,168, 467–475. [C ossRe ]
56.
Hu, Y.; Li, X.; Lang, A.W.; Zhang, Y.; Nu , S.R. Wa e imme sion aging o polydicyclopen adiene esin and glass ibe composi es.
Polym. Deg ad. S ab. 2016,124, 35–42. [C ossRe ]
57. Gil, L. Co k Composi es: A Re iew. Ma e ials 2009,2, 776–789. [C ossRe ]
58.
Ca alho, R.; Fe nandes, M.; Fanguei o, R. The in luence o co k on he he mal insula ion p ope ies o home ex iles. P ocedia
Eng. 2017,200, 252–259. [C ossRe ]
59.
Ama o, A.M.; Reis, P.N.B.; De Mou a, M.F.S.F. Delamina ion E ec on Bending Beha iou in Ca bon–Epoxy Composi es. S ain
2011,47, 203–208. [C ossRe ]
60.
Ama o, A.M.; Reis, P.N.B.; De Mou a, M.; San os, J.B. In luence o he specimen hickness on low eloci y impac beha io o
composi es. J. Polym. Eng. 2012,32, 53–58. [C ossRe ]
61.
Da id-Wes , O.S.; Nash, D.H.; Banks, W.M. An expe imen al s udy o damage accumula ion in balanced CFRP lamina es due o
epea ed impac . Compos. S uc . 2008,83, 247–258. [C ossRe ]