Poly(carboxylated ether)s as Cement Additives: The Effect of the Addition Method on Hydration Kinetics

Ci a ion: Belda ain, S.; Go acci, G.; S.
Dolado, J.; Ba que o, A.; Leiza, J.R.
Poly(ca boxyla ed e he )s as Cemen
Addi i es: The E ec o he Addi ion
Me hod on Hyd a ion Kine ics.
Ma e ials 2024,17, 5343. h ps://
doi.o g/10.3390/ma17215343
Academic Edi o : Geo Paul
Recei ed: 19 Sep embe 2024
Re ised: 23 Oc obe 2024
Accep ed: 29 Oc obe 2024
Published: 31 Oc obe 2024
Copy igh : © 2024 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/).
A icle
Poly(ca boxyla ed e he )s as Cemen Addi i es: The E ec o he
Addi ion Me hod on Hyd a ion Kine ics
Sa a Belda ain 1, Guido Go acci 2, Jo ge S. Dolado 2, Ai o Ba que o 1,* and Jose Ramon Leiza 1,*
1POLYMAT, Kimika Aplika ua Saila, Kimika Fakul a ea, Uni e si y o he Basque Coun y, UPV/EHU, Joxe
Ma i Ko a Zen oa, Tolosa Hi ibidea 72, 20018 Donos ia-San Sebas ián, Spain; [email p o ec ed]
2Cen o de Física de Ma e iales (CSIC, UPV/EHU) Ma e ials Physics Cen e (MPC), Paseo Manuel de
La dizabal 5, 20018 Donos ia-San Sebas ián, Spain; [email p o ec ed] (G.G.); [email p o ec ed] (J.S.D.)
*Co espondence: ai o .ba que [email p o ec ed] (A.B.); [email p o ec ed] (J.R.L.)
Abs ac : Polyca boxyla e e he (PCE) supe plas icise s ha e been widely used in cemen o mula-
ions. Howe e , i is no un il ecen ly ha se e al s udies ha e analysed he ela ionship be ween he
p ope ies and he molecula s uc u e. In he p esen wo k, PCEs wi h di e en side chain leng hs
and cha ge densi ies syn hesised h ough ee adical copolyme isa ion a e used o analyse he e ec
hey ha e on he hyd a ion o o dina y Po land cemen (OPC). I was ound ha he addi ion me hod
o hese PCEs o he OPC signi ican ly a ec s he hyd a ion kine ics o he cemen pas e. When
PCEs a e added h ough he di ec addi ion me hod, a linea dependency be ween he e a da ion
o hyd a ion and he mic os uc u e o he used PCEs is obse ed. On he con a y, when PCEs a e
added h ough he delayed addi ion me hod (PCEs a e added o he cemen pas e 5 min a e wa e ),
no e a da ion in hyd a ion is obse ed, bu he a e o hyd a ion is educed.
Keywo ds: hyd a ion kine ics; PCE supe plas icize ; di ec addi ion; delayed addi ion; o dina y
po land cemen
1. In oduc ion
I is easonable o s a e ha he ad ancemen o polyca boxyla e e he /es e (PCE) su-
pe plas icise s and conc e e echnology is happening concu en ly [
1
]. PCEs a e he newes
class o supe plas icise s ha ha e eplaced olde chemis ies based on lignosul ona es
(LS), polynaph halene sul ona es (PNS), o polymelamine sul ona es (PMS) [
2
] because o
hei excep ional capaci y o educe wa e . PCEs ha e comb-like s uc u es, wi h anionic
ca boxylic g oups o ming he backbone and non-ionic polye hylene glycol (PEG) uni s ac -
ing as pendan g oups (side chain) (Figu e 1a). One o he ad an ages o hese PCEs is hei
molecula e sa ili y [
3
], as hei mic os uc u e can be easily a ied by changing s uc u al
pa ame e s like he leng h o he side chains [
4
,
5
], backbone leng h [
6
], he a io be ween
he ca boxylic acid and side chains [
7
], e c. Due o hei a ie y and capaci y o educing
wa e , good wo kabili y [
8
] can be achie ed a e y low wa e - o-cemen a ios. This makes
PCEs indispensable in ad anced conc e e o mula ions, such as ul a-high-pe o mance
conc e e (UHPC) [9] o sel -compac ing conc e e (SCC) [10].
The knowledge o PCEs’ pe o mance was based on a ial and e o app oach un il
ecen ly, when Fla e al., in ending o unde s and he mic os uc u e–p ope y co ela ion,
s a ed o a ionalise hese ela ionships [
11
–
13
]. They de ined a model epea ing uni
(Figu e 1b), which desc ibes he molecula s uc u e o he PCE wi h only h ee cha ac e is ic
s uc u al pa ame e s: he numbe o e hylene glycol uni s in he side chain (P), he numbe
o monome uni s in he epea ing uni (N), and he numbe o epea ing uni s in he
chain (n).
Ma e ials 2024,17, 5343. h ps://doi.o g/10.3390/ma17215343 h ps://www.mdpi.com/jou nal/ma e ials
Ma e ials 2024,17, 5343 2 o 12
Ma e ials 2024, 17, x FOR PEER REVIEW 2 o 12
(a) (b)
Figu e 1. Schema ic illus a ion o (a) ypical PCE s uc u e and (b) he epea ing uni o a comb-
shaped copolyme conside ed by Fla e al. [11]. The comb copolyme con ains n segmen s, each
con aining N backbone monome s and a side chain o P e hylene oxide uni s.
In a la e wo k, Ma chon e al. [3] deeply analysed he effec ha PCEs ha e on ce-
men hyd a ion. In hei wo k, hey examined he mic os uc u e o PCEs syn hesised by
es e i ica ion wi h hyd a ion e a da ion in specially designed model cemen . In said
wo k, he au ho s analysed he hyd a ion kine ics using calo ime ic measu emen s, ex-
amining wo diffe en me hods o adding he PCE: di ec and delayed addi ion. In di ec
addi ion, he PCEs we e di ec ly added o he wa e be o e mixing i wi h he cemen o
o m he cemen pas e. In delayed addi ion, on he o he hand, pu e wa e was mixed wi h
he cemen i s , and he PCEs we e added i e minu es a e he cemen pas e was o med.
They disco e ed ha he hyd a ion e a da ion caused by he supe plas icise s was line-
a ly p opo ional o he o al numbe o ca boxyla e uni s dosed ia he PCE, and his
dependence was he same o bo h addi ion me hods. The excep ion was ha o di ec
addi ion, below a h eshold PCE dosage (c*), he e was e y li le hyd a ion e a da ion,
and he ela ionship was no ul illed. The ac ha he obse ed e a da ion in hyd a ion
o bo h addi ion me hods showed a simila dependence on he PCEs’ mic os uc u es
sugges ed ha e a da ion was caused by he same mechanism in bo h cases. The au ho s
ob ained quan i a i e exp essions ha co ela e he e a da ion in he maximum o he
hyd a ion peak (Δ ) wi h he mic os uc u es o he PCEs (de ined as a unc ion o he
cha ac e is ic pa ame e s) o bo h addi ion me hods. Thus, Equa ions (1) and (2) a ion-
alised he dependence o he hyd a ion e a da ion on PCEs’ molecula s uc u es, ex-
plaining his dependence as he esul o he numbe o epea ing uni s, 𝑛
 o
(𝑛
 −𝑛
), and he blocking capaci y o each o hem, 󰇡
⁄

⁄󰇢
⁄, which depends on he
elec ic ield induced by he polyme on he su ace.
Delayed addi ion: ∆𝑡 ∝ 𝑛
 󰇡
⁄

⁄󰇢
⁄ (1)
Di ec addi ion: ∆𝑡 ∝ (𝑛
 −𝑛
)󰇡
⁄

⁄󰇢
⁄ (2)
whe e Δ is he e a da ion o he maximum o he hyd a ion measu ed using calo ime y
(in hou s), 𝑛
 =
 is he numbe o epea uni s dosed in he sys em, 𝑛
 is he num-
be o epea uni s adso bed in e ingi e, 𝑐 is he concen a ion o PCE (in
µgPCE·gOPC−1), 𝑀 is he mola mass o a epea ing uni de ined in Equa ion (3) (in
g·mol−1), and 𝐶𝐸
⁄ (o N − 1) is he mola a io be ween ca boxyla e and es e g oups in
he PCE.
𝑀 =𝑃·𝑀
 +(𝐶 𝐸
⁄+1)·𝑀
 (3)
n
1 N2
1
P
2
…
…
Figu e 1. Schema ic illus a ion o (a) ypical PCE s uc u e and (b) he epea ing uni o a comb-
shaped copolyme conside ed by Fla e al. [
11
]. The comb copolyme con ains nsegmen s, each
con aining Nbackbone monome s and a side chain o Pe hylene oxide uni s.
In a la e wo k, Ma chon e al. [
3
] deeply analysed he e ec ha PCEs ha e on cemen
hyd a ion. In hei wo k, hey examined he mic os uc u e o PCEs syn hesised by es e i i-
ca ion wi h hyd a ion e a da ion in specially designed model cemen . In said wo k, he
au ho s analysed he hyd a ion kine ics using calo ime ic measu emen s, examining wo
di e en me hods o adding he PCE: di ec and delayed addi ion. In di ec addi ion, he
PCEs we e di ec ly added o he wa e be o e mixing i wi h he cemen o o m he cemen
pas e. In delayed addi ion, on he o he hand, pu e wa e was mixed wi h he cemen i s ,
and he PCEs we e added i e minu es a e he cemen pas e was o med. They disco e ed
ha he hyd a ion e a da ion caused by he supe plas icise s was linea ly p opo ional o
he o al numbe o ca boxyla e uni s dosed ia he PCE, and his dependence was he same
o bo h addi ion me hods. The excep ion was ha o di ec addi ion, below a h eshold
PCE dosage (c*), he e was e y li le hyd a ion e a da ion, and he ela ionship was no
ul illed. The ac ha he obse ed e a da ion in hyd a ion o bo h addi ion me hods
showed a simila dependence on he PCEs’ mic os uc u es sugges ed ha e a da ion
was caused by he same mechanism in bo h cases. The au ho s ob ained quan i a i e
exp essions ha co ela e he e a da ion in he maximum o he hyd a ion peak (
∆
) wi h
he mic os uc u es o he PCEs (de ined as a unc ion o he cha ac e is ic pa ame e s) o
bo h addi ion me hods. Thus, Equa ions (1) and (2) a ionalised he dependence o he
hyd a ion e a da ion on PCEs’ molecula s uc u es, explaining his dependence as he
esul o he numbe o epea ing uni s,
n o
RU
o
n o
RU −nE
RU
, and he blocking capaci y o
each o hem,
C/E
C/E+13/2
, which depends on he elec ic ield induced by he polyme on
he su ace.
Delayed addi ion : ∆ ∝n o
RUC/E
C/E+13/2
(1)
Di ec addi ion : ∆ ∝n o
RU −nE
RUC/E
C/E+13/2
(2)
whe e
∆
is he e a da ion o he maximum o he hyd a ion measu ed using calo ime y
(in hou s),
n o
RU =cPCE
MRU
is he numbe o epea uni s dosed in he sys em,
nE
RU
is he numbe
o epea uni s adso bed in e ingi e,
cPCE
is he concen a ion o PCE (in
µ
g
PCE·
g
OPC
−1
),
MRU
is he mola mass o a epea ing uni de ined in Equa ion (3) (in g
·
mol
−1
), and
C/E
(o N −1) is he mola a io be ween ca boxyla e and es e g oups in he PCE.
MRU =P·MSC +(C/E+1)·MBB (3)
whe e
P
is he side chain leng h,
MSC
is he mola mass o he side chain (e hylene oxide,
44.05 g
·
mol
−1
),
(C/E+1)
is he numbe o monome uni s in he epea ing uni , and
MBB
is he mola mass o he backbone monome (me hac ylic acid, 86.06 g·mol−1).
Ma e ials 2024,17, 5343 3 o 12
As men ioned, Ma chon e al. ca ied ou hei esea ch using PCEs syn hesised
h ough he es e i ica ion o a poly ac ylic acid backbone wi h me hyl poly(e hylene oxide),
as hey claim ha his ou e o e s he bes con ol on he mic os uc u e o he polyme .
None heless, he e is an al e na i e syn hesis me hod wi h wide use in indus y, which is
he ee adical copolyme isa ion o me hac ylic acid and polye hylene glycol me hac yla e
(PEGMA) mac omonome (see Figu e 2). Emaldi e al. p o ed ha when he chain leng h
o he PEGMA was long enough o make i soluble in acidic media, copolyme s wi h
well-con olled molecula s uc u es and homogeneous composi ions could be achie ed by
ollowing semi-ba ch polyme isa ion s a egies [
14
–
16
]. This app oach is he mos common
me hod due o i s simple expe imen al p ocess and cos -e ec i eness [2].
Ma e ials 2024, 17, x FOR PEER REVIEW 3 o 12
whe e 𝑃 is he side chain leng h, 𝑀 is he mola mass o he side chain (e hylene oxide,
44.05 g·mol
−1
), (𝐶 𝐸
⁄+1) is he numbe o monome uni s in he epea ing uni , and 𝑀
is he mola mass o he backbone monome (me hac ylic acid, 86.06 g·mol
−1
).
As men ioned, Ma chon e al. ca ied ou hei esea ch using PCEs syn hesised
h ough he es e i ica ion o a poly ac ylic acid backbone wi h me hyl poly(e hylene ox-
ide), as hey claim ha his ou e offe s he bes con ol on he mic os uc u e o he poly-
me . None heless, he e is an al e na i e syn hesis me hod wi h wide use in indus y,
which is he ee adical copolyme isa ion o me hac ylic acid and polye hylene glycol
me hac yla e (PEGMA) mac omonome (see Figu e 2). Emaldi e al. p o ed ha when he
chain leng h o he PEGMA was long enough o make i soluble in acidic media, copoly-
me s wi h well-con olled molecula s uc u es and homogeneous composi ions could be
achie ed by ollowing semi-ba ch polyme isa ion s a egies [14–16]. This app oach is he
mos common me hod due o i s simple expe imen al p ocess and cos -effec i eness [2].
Figu e 2. Mechanism o he ee adical copolyme isa ion me hod o p oduce M-PEG- ype PCEs.
The au ho s also s udied he effec o PCEs p oduced by ee adical copolyme isa-
ion on he hyd a ion kine ics o comme cial o dina y Po land cemen (OPC). Thei e-
sul s show ha he hyd a ion kine ics o he PCE added using he di ec addi ion me hod
o comme cial OPC ollow he same ends desc ibed by Ma chon e al. [3].
In ou p e ious wo k, we expanded he s udy p esen ed by Emaldi e al. wi h a wide
ange o PCEs, pa icula ly ocusing on ha ing diffe en composi ions ( a ying N and P
pa ame e s) [17]. The e, we obse ed a linea co ela ion be ween he hyd a ion delay and
he s uc u e o he PCEs when he addi ion me hod o he PCE was di ec addi ion. In he
p esen wo k, a new se o expe imen s we e ca ied ou o in es iga e he effec o delay-
ing he addi ion o he PCE o 5 min a e mixing he cemen and he wa e on he e a -
da ion o cemen hyd a ion. To ensu e ha he condi ions we e he same, he OPC and
PCEs we e om he same ba ch as hose used in ou p e ious wo k. We show ha , su -
p isingly, he esul s o he delayed addi ion a e signi ican ly diffe en om hose o di ec
addi ion. Indeed, no hyd a ion e a da ion is obse ed, bu a educ ion o hyd a ion is
obse ed.
2. Expe imen al P ocedu e
2.1. Ma e ials
Two PCE se ies (M and L) we e used wi h diffe en e hylene oxide (EO) uni s (22.5
and 45) and con aining diffe en me hac ylic acid/poly(e hylene glycol me hac yla e)
(MAA/PEGMA) mol a ios (0.67/1, 1/1, 3/1, and 6/1). The PCEs we e syn hesised wi h ee
adical semi-ba ch aqueous solu ion polyme isa ion in wa e , wi h KPS as he ini ia o a
80 °C. A de ailed desc ip ion o he syn hesis and cha ac e isa ion o hese PCEs can be
Figu e 2. Mechanism o he ee adical copolyme isa ion me hod o p oduce M-PEG- ype PCEs.
The au ho s also s udied he e ec o PCEs p oduced by ee adical copolyme isa ion
on he hyd a ion kine ics o comme cial o dina y Po land cemen (OPC). Thei esul s
show ha he hyd a ion kine ics o he PCE added using he di ec addi ion me hod o
comme cial OPC ollow he same ends desc ibed by Ma chon e al. [3].
In ou p e ious wo k, we expanded he s udy p esen ed by Emaldi e al. wi h a wide
ange o PCEs, pa icula ly ocusing on ha ing di e en composi ions ( a ying N and P
pa ame e s) [
17
]. The e, we obse ed a linea co ela ion be ween he hyd a ion delay and
he s uc u e o he PCEs when he addi ion me hod o he PCE was di ec addi ion. In
he p esen wo k, a new se o expe imen s we e ca ied ou o in es iga e he e ec o
delaying he addi ion o he PCE o 5 min a e mixing he cemen and he wa e on he
e a da ion o cemen hyd a ion. To ensu e ha he condi ions we e he same, he OPC
and PCEs we e om he same ba ch as hose used in ou p e ious wo k. We show ha ,
su p isingly, he esul s o he delayed addi ion a e signi ican ly di e en om hose o
di ec addi ion. Indeed, no hyd a ion e a da ion is obse ed, bu a educ ion o hyd a ion
is obse ed.
2. Expe imen al P ocedu e
2.1. Ma e ials
Two PCE se ies (M and L) we e used wi h di e en e hylene oxide (EO) uni s (22.5
and 45) and con aining di e en me hac ylic acid/poly(e hylene glycol me hac yla e)
(MAA/PEGMA) mol a ios (0.67/1, 1/1, 3/1, and 6/1). The PCEs we e syn hesised wi h
ee adical semi-ba ch aqueous solu ion polyme isa ion in wa e , wi h KPS as he ini ia o
a 80
◦
C. A de ailed desc ip ion o he syn hesis and cha ac e isa ion o hese PCEs can
be ound in Sec ion S1 o he Supplemen a y Ma e ials. A summa y o he mos ele an
cha ac e is ics o he syn hesised PCEs is shown in Table 1.
Ma e ials 2024,17, 5343 4 o 12
Table 1. Cha ac e is ic s uc u al pa ame e s o he used PCEs as de ined by Fla e al. [11].
Name o PCE MMA/PEGMA Ra io (mol/mol) —–
Mn(kg/mol) P N n
0.67/1 M 0.67/1 40.5
22.5
1.67 38
1/1 M 1/1 27.6 2 25
3/1 M 3/1 24.4 4 19
6/1 M 6/1 24.5 7 16
0.67/1 L 0.67/1 27.2
45
1.67 13
1/1 L 1/1 29.0 2 14
3/1 L 3/1 20.5 4 9
6/1 L 6/1 17.2 7 7
The cemen used was CEM ype I 52.2R o dina y Po land cemen (OPC), which was
kindly supplied by Lemona Cemen s S.A. (Lemoa, Spain). I s mine alogical composi ion
and speci ic su ace a ea can be ound in Sec ion S2 o he Supplemen a y Ma e ials.
2.2. Hyd a ion Kine ics o he OPC
The hyd a ion kine ics we e ca ied ou in a TAM ai conduc ion calo ime e a oom
empe a u e o 48 h, wi h wa e as e e ence ma e ial. Cemen pas es wi h a o al mass o
5 g we e p epa ed wi h a 0.4 wa e - o-cemen a io. The componen s we e mixed using a
o ex mixe . Di e en concen a ions (be ween 1 and 4 mg
PCE
/g
OPC
) o he syn hesised
PCEs we e added o he cemen pas es ollowing wo di e en addi ion me hods: di ec
and delayed addi ion.
In di ec addi ion, he PCEs we e i s mixed wi h he wa e ha la e was added o
he cemen . As soon as he wa e and PCE mix u e was added o he cemen , he sys em
was mixed as ollows: 90 s a 800 pm, 60 s o pause, and 90 s a 800 pm. In delayed
addi ion, he PCEs we e added o he mix u e 5 min a e mixing he wa e and he cemen .
Fo his me hod, nea wa e was mixed wi h cemen ollowing he same mixing p ocedu e
desc ibed o di ec addi ion. A e 5 min, a PCE aqueous solu ion (a he concen a ion ha
was p oduced) was added, and he cemen pas e was mixed o an ex a 60 s a 800 pm.
The same OPC wi hou PCEs was used as a e e ence sample. The s a ing ime o he
measu emen was aken as he momen when he OPC and he wa e we e mixed.
The hyd a ion kine ics we e s udied by measu ing he eleased hea when he cemen
was mixed wi h wa e and PCEs. The added PCEs had di e en MAA/PEGMA a ios (N)
and di e en side chain leng hs (P) and we e added a di e en dosages using di ec and
delayed addi ion.
3. Resul s and Discussion
3.1. Hyd a ion Kine ics: Di ec s. Delayed Addi ion
In he le column, Figu e 3shows he hyd a ion kine ics when he PCE is added using
di ec addi ion o he PCEs o se ies M (see Table 1) a di e en doses, and he hyd a ion
kine ics o delayed addi ion a e shown on he igh . The same esul s o se ies L can be
ound in Figu e S1 in he Supplemen a y Ma e ials.
The esul s on he le side (di ec addi ion) we e adap ed and ep in ed wi h pe mis-
sion om ou p e ious publica ion [
17
]. The e, i can be obse ed ha o any MAA/PEGMA
a io, as he PCE concen a ion inc eases, he hyd a ion peak is mo e e a ded. No ably,
he o e all shape o he plo is he same, bu i is displaced o longe imes. As i was
discussed, he e a da ion in hyd a ion (
∆
) was ound o be p opo ional o he ca boxy-
la e dosage, and all PCEs i in a mas e cu e, p o ing ha he mic os uc u e o PCEs
could be co ela ed o he hyd a ion delay o he OPC. These esul s a e compa able o he
delayed addi ion da a published by Ma chon e al. [
3
]. I is belie ed ha his disc epancy
is due o he con en o C
3
A and he educed ole o e ingi e in compe ing o he PCE
adso p ion [17,18].
Ma e ials 2024,17, 5343 5 o 12
Ma e ials 2024, 17, x FOR PEER REVIEW 5 o 12
o he ca boxyla e dosage, and all PCEs i in a mas e cu e, p o ing ha he mic os uc-
u e o PCEs could be co ela ed o he hyd a ion delay o he OPC. These esul s a e com-
pa able o he delayed addi ion da a published by Ma chon e al. [3]. I is belie ed ha
his disc epancy is due o he con en o C
3
A and he educed ole o e ingi e in compe -
ing o he PCE adso p ion [17,18].
The esul s on he igh side o Figu e 3 co espond o he expe imen s in which PCEs
we e added acco ding o he delayed addi ion me hod. When his me hod is used, he
o e all shape o he plo signi ican ly changes. Ins ead o only a e a da ion o he hyd a-
ion, a dec ease in he in ensi y o he main hyd a ion peak is obse ed, bu he posi ion
o he maximum o he peak is he same. This educ ion o he peak becomes mo e signi -
ican when he MAA/PEGMA a io o PCE concen a ion is inc eased. A e a da ion o
he peak is only obse ed a he highe PCE doses. As a esul o his beha iou , i only
he posi ion o he maximum is conside ed, he e a da ion (∆𝑡) would be conside ed ze o
in mos cases. Thus, he analysis o his beha iou canno be conduc ed as a unc ion o
∆𝑡.
As men ioned, a educ ion in hyd a ion in delayed addi ion occu s du ing he i s
hou s (<20 h) o hyd a ion. In e es ingly, he o al eleased hea a 48 h (analysis ime, see
Figu e 4) is compa able o ha o he sys ems in which he PCEs we e added using di ec
addi ion due o he appea ance o a second peak a longe hyd a ion imes (>20 h). Because
o his, we p opose o base he analysis o he impac o hese PCEs in he hyd a ion kine -
ics o he OPC on he educed hea o hyd a ion o he main peak (compa ed o he e e -
ence), which is de ined as ∆𝑄 = 𝑄 −𝑄
. Thus, ∆𝑄 will be used in he same way
ha ∆𝑡 was used in he pionee ing wo k o Ma chon e al. [3].
MAA/PEGMA
mol a io
Hyd a ion kine ics
Di ec addi ion Delayed addi ion
0.67/1
1/1
Ma e ials 2024, 17, x FOR PEER REVIEW 6 o 12
3/1
6/1
Figu e 3. Released hea o hyd a ion o e ime o PCEs o se ies M and diffe en MAA/PEGMA
mola a ios (0.67/1, 1/1, 3/1, and 6/1) a diffe en PCE dosages (blue—1 mg
PCE
/g
OPC
; ed—2
mg
PCE
/g
OPC
; g een—3 mg
PCE
/g
OPC
; pu ple—4 mg
PCE
/g
OPC
). Black line belongs o he e e ence sample,
o which no PCE was added. Da a aken om e e ence [17].
Figu e 4 shows he hea o hyd a ion (𝑄) o e ime o he PCE 3/1 M a diffe en
dosages using di ec (con inuous g ey line) and delayed addi ion (dashed g ey line) as an
example. The es o he sys ems show a simila end and a e p esen ed in Figu e S2 in
he Supplemen a y Ma e ials.
3/1 M
1 mg
PCE
/g
OPC
2 mg
PCE
/g
OPC
3 mg
PCE
/g
OPC
4 mg
PCE
/g
OPC
Re e ence 1 mgPCE/gOPC 2 mgPCE/gOPC 3 mgPCE/gOPC 4 mgPCE/gOPC
Figu e 3. Released hea o hyd a ion o e ime o PCEs o se ies M and di e en MAA/PEGMA
mola a ios (0.67/1, 1/1, 3/1, and 6/1) a di e en PCE dosages (blue—1 mg
PCE
/g
OPC
; ed—2
mg
PCE
/g
OPC
; g een—3 mg
PCE
/g
OPC
; pu ple—4 mg
PCE
/g
OPC
). Black line belongs o he e e ence
sample, o which no PCE was added. Da a aken om e e ence [17].
The esul s on he igh side o Figu e 3co espond o he expe imen s in which
PCEs we e added acco ding o he delayed addi ion me hod. When his me hod is used,
he o e all shape o he plo signi ican ly changes. Ins ead o only a e a da ion o he
hyd a ion, a dec ease in he in ensi y o he main hyd a ion peak is obse ed, bu he
posi ion o he maximum o he peak is he same. This educ ion o he peak becomes mo e

Ma e ials 2024,17, 5343 6 o 12
signi ican when he MAA/PEGMA a io o PCE concen a ion is inc eased. A e a da ion
o he peak is only obse ed a he highe PCE doses. As a esul o his beha iou , i only
he posi ion o he maximum is conside ed, he e a da ion (
∆
) would be conside ed ze o
in mos cases. Thus, he analysis o his beha iou canno be conduc ed as a unc ion o
∆
.
As men ioned, a educ ion in hyd a ion in delayed addi ion occu s du ing he i s
hou s (<20 h) o hyd a ion. In e es ingly, he o al eleased hea a 48 h (analysis ime, see
Figu e 4) is compa able o ha o he sys ems in which he PCEs we e added using di ec
addi ion due o he appea ance o a second peak a longe hyd a ion imes (>20 h). Because
o his, we p opose o base he analysis o he impac o hese PCEs in he hyd a ion kine ics
o he OPC on he educed hea o hyd a ion o he main peak (compa ed o he e e ence),
which is de ined as
∆Q=Q e −Qsample
. Thus,
∆Q
will be used in he same way ha
∆
was used in he pionee ing wo k o Ma chon e al. [3].
Ma e ials 2024, 17, x FOR PEER REVIEW 6 o 12
3/1
6/1
Figu e 3. Released hea o hyd a ion o e ime o PCEs o se ies M and diffe en MAA/PEGMA
mola a ios (0.67/1, 1/1, 3/1, and 6/1) a diffe en PCE dosages (blue—1 mg
PCE
/g
OPC
; ed—2
mg
PCE
/g
OPC
; g een—3 mg
PCE
/g
OPC
; pu ple—4 mg
PCE
/g
OPC
). Black line belongs o he e e ence sample,
o which no PCE was added. Da a aken om e e ence [17].
Figu e 4 shows he hea o hyd a ion (𝑄) o e ime o he PCE 3/1 M a diffe en
dosages using di ec (con inuous g ey line) and delayed addi ion (dashed g ey line) as an
example. The es o he sys ems show a simila end and a e p esen ed in Figu e S2 in
he Supplemen a y Ma e ials.
3/1 M
1 mg
PCE
/g
OPC
2 mg
PCE
/g
OPC
3 mg
PCE
/g
OPC
4 mg
PCE
/g
OPC
Re e ence 1 mgPCE/gOPC 2 mgPCE/gOPC 3 mgPCE/gOPC 4 mgPCE/gOPC
Ma e ials 2024, 17, x FOR PEER REVIEW 7 o 12
Figu e 4. To al hea o hyd a ion o e ime o he PCE o se ies M and an MMA/PEGMA mola
a io o 3/1 added o he sys em h ough di ec (con inuous g ey line) and delayed addi ion (dashed
g ey line). Black line belongs o he e e ence sample, o which no PCE was added.
I is no ewo hy ha he slope o he e e ence sample is simila o he slope o he
di ec addi ion samples, meaning ha he a e o hyd a ion is he same, e en i a e a da-
ion is occu ing. On he o he hand, when PCEs we e added h ough delayed addi ion,
he hyd a ion a e was slowe (lowe slope). Ne e heless, he o al educ ion o hyd a ion
is simila o bo h addi ion me hods. In e es ingly, he hyd a ion a es o he di ec and
delayed sys ems become compa able when high PCE dosages a e used.
3.2. Co ela ion o he To al Hea o Hyd a ion wi h he Mic os uc u e o he PCEs
Du ing he las ew yea s, se e al g oups ha e been wo king on a ionalising he e -
ec o he mic os uc u e o comb-shaped copolyme s, such as he PCEs used in his wo k,
in he p ope ies o cemen pas es [3,11,16,17,19]. As p e iously men ioned, Ma chon e
al. [3] we e able o linea ly co ela e he mic os uc u e and dosage o he PCEs used in a
model clinke wi h i s hyd a ion e a da ion. La e , he equa ions used in ha wo k o a
delayed addi ion we e alida ed in a comme cial OPC o di ec addi ion [17]. In he p e-
ious sec ion, we could obse e ha when he same PCEs we e added o he same OPC
using a delayed addi ion, no e a da ion occu ed. As his sys em shows a slowe hyd a-
ion a e, he eleased hea du ing he main hyd a ion peak (co esponding o he com-
bined C
3
S and C
3
A hyd a ion) was analysed by applying he equa ions de eloped by Ma -
chon e al. [3]
In Figu e 5, he o al eleased hea a e 48 h is p esen ed o e he ca boxyla e dosage.
This pa ame e , named X
0
is he numbe o ca boxyla e g oups added o he sys em and
can be calcula ed using Equa ion (4) and has a dependence on he PCE dosage (𝑐), mo-
la a io o MAA/PEGMA (𝐶/𝐸), and mola mass o he epea ing uni (𝑀, Equa ion
(3)).
𝑋=𝑐
 ·/


(4)
Di ec addi ion Delayed addi ion
M
y = -2.70x + 216.2
R² = 0.76
0
50
100
150
200
250
0 5 10 15 20
Q o (J/g)
X0 (AU)
y = -3.35x + 214.9
R² = 0.87
0
50
100
150
200
250
0 5 10 15 20
Q o (J/g)
X0 (AU)
Figu e 4. To al hea o hyd a ion o e ime o he PCE o se ies M and an MMA/PEGMA mola
a io o 3/1 added o he sys em h ough di ec (con inuous g ey line) and delayed addi ion (dashed
g ey line). Black line belongs o he e e ence sample, o which no PCE was added.
Figu e 4shows he hea o hyd a ion (
Q
) o e ime o he PCE 3/1 M a di e en
dosages using di ec (con inuous g ey line) and delayed addi ion (dashed g ey line) as an
example. The es o he sys ems show a simila end and a e p esen ed in Figu e S2 in he
Supplemen a y Ma e ials.
I is no ewo hy ha he slope o he e e ence sample is simila o he slope o he
di ec addi ion samples, meaning ha he a e o hyd a ion is he same, e en i a e a da ion
is occu ing. On he o he hand, when PCEs we e added h ough delayed addi ion, he
hyd a ion a e was slowe (lowe slope). Ne e heless, he o al educ ion o hyd a ion
is simila o bo h addi ion me hods. In e es ingly, he hyd a ion a es o he di ec and
delayed sys ems become compa able when high PCE dosages a e used.
Ma e ials 2024,17, 5343 7 o 12
3.2. Co ela ion o he To al Hea o Hyd a ion wi h he Mic os uc u e o he PCEs
Du ing he las ew yea s, se e al g oups ha e been wo king on a ionalising he e ec
o he mic os uc u e o comb-shaped copolyme s, such as he PCEs used in his wo k, in
he p ope ies o cemen pas es [
3
,
11
,
16
,
17
,
19
]. As p e iously men ioned, Ma chon e al. [
3
]
we e able o linea ly co ela e he mic os uc u e and dosage o he PCEs used in a model
clinke wi h i s hyd a ion e a da ion. La e , he equa ions used in ha wo k o a delayed
addi ion we e alida ed in a comme cial OPC o di ec addi ion [
17
]. In he p e ious
sec ion, we could obse e ha when he same PCEs we e added o he same OPC using a
delayed addi ion, no e a da ion occu ed. As his sys em shows a slowe hyd a ion a e,
he eleased hea du ing he main hyd a ion peak (co esponding o he combined C
3
S and
C3A hyd a ion) was analysed by applying he equa ions de eloped by Ma chon e al. [3]
In Figu e 5, he o al eleased hea a e 48 h is p esen ed o e he ca boxyla e dosage.
This pa ame e , named X
0
is he numbe o ca boxyla e g oups added o he sys em and
can be calcula ed using Equa ion (4) and has a dependence on he PCE dosage (
cPCE
), mola
a io o MAA/PEGMA (C/E), and mola mass o he epea ing uni (MRU, Equa ion (3)).
X0=cPCE·C/E
MRU
(4)
Ma e ials 2024, 17, x FOR PEER REVIEW 7 o 12
Figu e 4. To al hea o hyd a ion o e ime o he PCE o se ies M and an MMA/PEGMA mola
a io o 3/1 added o he sys em h ough di ec (con inuous g ey line) and delayed addi ion (dashed
g ey line). Black line belongs o he e e ence sample, o which no PCE was added.
I is no ewo hy ha he slope o he e e ence sample is simila o he slope o he
di ec addi ion samples, meaning ha he a e o hyd a ion is he same, e en i a e a da-
ion is occu ing. On he o he hand, when PCEs we e added h ough delayed addi ion,
he hyd a ion a e was slowe (lowe slope). Ne e heless, he o al educ ion o hyd a ion
is simila o bo h addi ion me hods. In e es ingly, he hyd a ion a es o he di ec and
delayed sys ems become compa able when high PCE dosages a e used.
3.2. Co ela ion o he To al Hea o Hyd a ion wi h he Mic os uc u e o he PCEs
Du ing he las ew yea s, se e al g oups ha e been wo king on a ionalising he e -
ec o he mic os uc u e o comb-shaped copolyme s, such as he PCEs used in his wo k,
in he p ope ies o cemen pas es [3,11,16,17,19]. As p e iously men ioned, Ma chon e
al. [3] we e able o linea ly co ela e he mic os uc u e and dosage o he PCEs used in a
model clinke wi h i s hyd a ion e a da ion. La e , he equa ions used in ha wo k o a
delayed addi ion we e alida ed in a comme cial OPC o di ec addi ion [17]. In he p e-
ious sec ion, we could obse e ha when he same PCEs we e added o he same OPC
using a delayed addi ion, no e a da ion occu ed. As his sys em shows a slowe hyd a-
ion a e, he eleased hea du ing he main hyd a ion peak (co esponding o he com-
bined C
3
S and C
3
A hyd a ion) was analysed by applying he equa ions de eloped by Ma -
chon e al. [3]
In Figu e 5, he o al eleased hea a e 48 h is p esen ed o e he ca boxyla e dosage.
This pa ame e , named X
0
is he numbe o ca boxyla e g oups added o he sys em and
can be calcula ed using Equa ion (4) and has a dependence on he PCE dosage (𝑐), mo-
la a io o MAA/PEGMA (𝐶/𝐸), and mola mass o he epea ing uni (𝑀, Equa ion
(3)).
𝑋=𝑐
 ·/


(4)
Di ec addi ion Delayed addi ion
M
y = -2.70x + 216.2
R² = 0.76
0
50
100
150
200
250
0 5 10 15 20
Q o (J/g)
X0 (AU)
y = -3.35x + 214.9
R² = 0.87
0
50
100
150
200
250
0 5 10 15 20
Q o (J/g)
X0 (AU)
Ma e ials 2024, 17, x FOR PEER REVIEW 8 o 12
L
Figu e 5. To al hea o hyd a ion, 𝑄

, as a unc ion o he dosage o ca boxylic g oups, 𝑥

, o
cemen pas es p epa ed h ough he di ec and delayed addi ion o PCEs wi h diffe en side chain
leng hs (M and L se ies).
The o al eleased hea o hyd a ion a e 48 h plo ed o e he ca boxyla e dosage o
PCEs om diffe en se ies (M and L) and diffe en addi ion me hods (di ec and delayed)
showed ha he o al hea o hyd a ion dec eases when he ca boxyla e dosage inc eases.
I bo h se ies a e compa ed, a mo e nega i e slope is obse ed when M se ies a e used.
Independen ly o he se ies, he slope becomes mo e nega i e when delayed addi ion is
used.
Howe e , as ∆𝑡 was he analysed pa ame e in p e ious wo ks, ∆𝑄 was calcula ed
o a mo e exhaus i e s udy by conside ing he hea eleased du ing he hyd a ion o C
3
S
and C
3
A a he same ime. ∆𝑄 was calcula ed using Equa ion (5).
∆𝑄 = 𝑄 −𝑄 (5)
whe e ∆𝑄 is he diffe ence in he hea eleased du ing he main hyd a ion peak be ween
he e e ence (𝑄) and each sys em (𝑄). The main hyd a ion peak was conside ed
om poin 1 o poin 2, as shown in Figu e 6.
Figu e 6. Rep esen a ion o he a eas used o ΔQ calcula ion conside ing he a eas om he induc-
ion pe iod (poin 1) o he minimum o in lec ion poin (poin 2) o he e e ence and sys ems
con aining PCEs added using he delayed addi ion me hod. The black line ep esen s he hyd a ion
calo ime y o he OPC wi h no PCE, and he g een line he hyd a ion calo ime y o he OPC wi h
he PCE added by delayed addi ion me hod.
The uppe g aphs shown in Figu e 7 p esen he e a da ion o he maximum o he
hyd a ion (∆𝑡) cu e plo ed as a unc ion o he numbe o ca boxyla e g oups (X
0
) calcu-
la ed using Equa ion (4) o he di ec addi ion me hod. In ag eemen wi h he esul s o
Ma chon e al. [3], he e a da ion o he hyd a ion o he main peak inc eases linea ly
wi h he amoun o ca boxyla e g oups added o he sys em. In addi ion, o he same
y = -1.68x + 212.2
R² = 0.41
0
50
100
150
200
250
0246810
Q o (J/g)
X0 (AU)
y = -2.83x + 209.8
R² = 0.87
0
50
100
150
200
250
0246810
Q o (J/g)
X0 (AU)
Figu e 5. To al hea o hyd a ion,
Q o
, as a unc ion o he dosage o ca boxylic g oups,
x0
, o cemen
pas es p epa ed h ough he di ec and delayed addi ion o PCEs wi h di e en side chain leng hs (M
and L se ies).
The o al eleased hea o hyd a ion a e 48 h plo ed o e he ca boxyla e dosage o
PCEs om di e en se ies (M and L) and di e en addi ion me hods (di ec and delayed)
showed ha he o al hea o hyd a ion dec eases when he ca boxyla e dosage inc eases.
I bo h se ies a e compa ed, a mo e nega i e slope is obse ed when M se ies a e used.
Independen ly o he se ies, he slope becomes mo e nega i e when delayed addi ion
is used.
Howe e , as
∆
was he analysed pa ame e in p e ious wo ks,
∆Q
was calcula ed o
a mo e exhaus i e s udy by conside ing he hea eleased du ing he hyd a ion o C
3
S and
C3A a he same ime. ∆Qwas calcula ed using Equa ion (5).
∆Q=Q e −Qsample (5)
Ma e ials 2024,17, 5343 8 o 12
whe e
∆Q
is he di e ence in he hea eleased du ing he main hyd a ion peak be ween
he e e ence (
Q e
) and each sys em (
Qsample
). The main hyd a ion peak was conside ed
om poin 1 o poin 2, as shown in Figu e 6.
Ma e ials 2024, 17, x FOR PEER REVIEW 8 o 12
L
Figu e 5. To al hea o hyd a ion, 𝑄

, as a unc ion o he dosage o ca boxylic g oups, 𝑥

, o
cemen pas es p epa ed h ough he di ec and delayed addi ion o PCEs wi h diffe en side chain
leng hs (M and L se ies).
The o al eleased hea o hyd a ion a e 48 h plo ed o e he ca boxyla e dosage o
PCEs om diffe en se ies (M and L) and diffe en addi ion me hods (di ec and delayed)
showed ha he o al hea o hyd a ion dec eases when he ca boxyla e dosage inc eases.
I bo h se ies a e compa ed, a mo e nega i e slope is obse ed when M se ies a e used.
Independen ly o he se ies, he slope becomes mo e nega i e when delayed addi ion is
used.
Howe e , as ∆𝑡 was he analysed pa ame e in p e ious wo ks, ∆𝑄 was calcula ed
o a mo e exhaus i e s udy by conside ing he hea eleased du ing he hyd a ion o C
3
S
and C
3
A a he same ime. ∆𝑄 was calcula ed using Equa ion (5).
∆𝑄 = 𝑄 −𝑄 (5)
whe e ∆𝑄 is he diffe ence in he hea eleased du ing he main hyd a ion peak be ween
he e e ence (𝑄) and each sys em (𝑄). The main hyd a ion peak was conside ed
om poin 1 o poin 2, as shown in Figu e 6.
Figu e 6. Rep esen a ion o he a eas used o ΔQ calcula ion conside ing he a eas om he induc-
ion pe iod (poin 1) o he minimum o in lec ion poin (poin 2) o he e e ence and sys ems
con aining PCEs added using he delayed addi ion me hod. The black line ep esen s he hyd a ion
calo ime y o he OPC wi h no PCE, and he g een line he hyd a ion calo ime y o he OPC wi h
he PCE added by delayed addi ion me hod.
The uppe g aphs shown in Figu e 7 p esen he e a da ion o he maximum o he
hyd a ion (∆𝑡) cu e plo ed as a unc ion o he numbe o ca boxyla e g oups (X
0
) calcu-
la ed using Equa ion (4) o he di ec addi ion me hod. In ag eemen wi h he esul s o
Ma chon e al. [3], he e a da ion o he hyd a ion o he main peak inc eases linea ly
wi h he amoun o ca boxyla e g oups added o he sys em. In addi ion, o he same
y = -1.68x + 212.2
R² = 0.41
0
50
100
150
200
250
0246810
Q o (J/g)
X0 (AU)
y = -2.83x + 209.8
R² = 0.87
0
50
100
150
200
250
0246810
Q o (J/g)
X0 (AU)
Figu e 6. Rep esen a ion o he a eas used o
∆
Q calcula ion conside ing he a eas om he induc ion
pe iod (poin 1) o he minimum o in lec ion poin (poin 2) o he e e ence and sys ems con aining
PCEs added using he delayed addi ion me hod. The black line ep esen s he hyd a ion calo ime y
o he OPC wi h no PCE, and he g een line he hyd a ion calo ime y o he OPC wi h he PCE added
by delayed addi ion me hod.
The uppe g aphs shown in Figu e 7p esen he e a da ion o he maximum o
he hyd a ion (
∆
) cu e plo ed as a unc ion o he numbe o ca boxyla e g oups (X
0
)
calcula ed using Equa ion (4) o he di ec addi ion me hod. In ag eemen wi h he esul s
o Ma chon e al. [
3
], he e a da ion o he hyd a ion o he main peak inc eases linea ly
wi h he amoun o ca boxyla e g oups added o he sys em. In addi ion, o he same
MAA/PEGMA mola a io, he esul s o bo h se ies can be i ed o he same plo (as
demons a ed in Figu e 8o ou p e ious publica ion [17]).
On he o he hand, he bo om g aphs in Figu e 7show he educ ion o he hea o
he main hyd a ion peak (
∆Q
) o e he numbe o ca boxyla e g oups (X
0
) added o he
sys em o he delayed addi ion me hod. When se ies M is analysed, a linea dependence
is obse ed, which is a unc ion o he MAA/PEGMA mola a io as in he case o
∆
in
di ec addi ion. Ne e heless, se ies L di e s signi ican ly om he esul s analysed so
a . When PCEs wi h low MAA/PEGMA mola a ios a e used, almos no educ ion in
hyd a ion is obse ed, e en i a di e ence was obse ed when analysing he hyd a ion
cu es (see Figu e 3and Figu e S1 in he Supplemen a y Ma e ials). Mo eo e , i he slopes
o PCEs wi h he same MAA/PEGMA mola a ios and di e en se ies a e compa ed, a
signi ican di e ence is obse ed. The e o e, we can in e ha
∆Q
has a dependency on
he side chain leng h (P). Because he sys em does no show any e a da ion in hyd a ion
and he hea eleased is P-dependen , he analysis p oposed by Ma chon e al. [
3
] and
applied o a di ec addi ion sys em when he same PCEs and OPCs we e used [
17
] canno
be pu sued u he .
Ma e ials 2024,17, 5343 9 o 12
Ma e ials 2024, 17, x FOR PEER REVIEW 9 o 12
MAA/PEGMA mola a io, he esul s o bo h se ies can be i ed o he same plo (as
demons a ed in Figu e 8 o ou p e ious publica ion [17]).
On he o he hand, he bo om g aphs in Figu e 7 show he educ ion o he hea o
he main hyd a ion peak (∆𝑄) o e he numbe o ca boxyla e g oups (X0) added o he
sys em o he delayed addi ion me hod. When se ies M is analysed, a linea dependence
is obse ed, which is a unc ion o he MAA/PEGMA mola a io as in he case o ∆𝑡 in
di ec addi ion. Ne e heless, se ies L diffe s signi ican ly om he esul s analysed so a .
When PCEs wi h low MAA/PEGMA mola a ios a e used, almos no educ ion in hyd a-
ion is obse ed, e en i a diffe ence was obse ed when analysing he hyd a ion cu es
(see Figu es 3 and S1 in he Supplemen a y Ma e ials). Mo eo e , i he slopes o PCEs
wi h he same MAA/PEGMA mola a ios and diffe en se ies a e compa ed, a signi ican
diffe ence is obse ed. The e o e, we can in e ha ∆𝑄 has a dependency on he side
chain leng h (P). Because he sys em does no show any e a da ion in hyd a ion and he
hea eleased is P-dependen , he analysis p oposed by Ma chon e al. [3] and applied o
a di ec addi ion sys em when he same PCEs and OPCs we e used [17] canno be pu sued
u he .
M se ies L se ies
Di ec addi ion
Delayed addi ion
Figu e 7. Re a da ion o hyd a ion o he main peak in di ec addi ion ( op g aphs) and educ ion
o hyd a ion hea o he main peak in delayed addi ion (bo om g aphs) as a unc ion o dosage o
ca boxylic g oups o PCEs o se ies M (le side) and L ( igh side) wi h diffe en MAA/PEGMA
mol a ios.
3.3. Unde s anding he Diffe ences Be ween Di ec and Delayed PCE Addi ion
Du ing Hyd a ion
The lack o p esence o PCE in he i s 5 min o mixing cemen wi h wa e is espon-
sible o a signi ican change in he hyd a ion cu es due o a change in he hyd a ion a e
y = 4.5317x
R² = 0.9882
y = 3.3821x
R² = 0.9889
y = 2.1528x
R² = 0.9951
y = 1.7964x
R² = 0.9929
0
5
10
15
20
25
30
0 5 10 15 20
Δ (h)
x0(AU)
0.67/1 M 1/1 M
3/1 M 6/1 M
y = 4.8434x
R² = 0.968
y = 3.6108x
R² = 0.9748
y = 1.9253x
R² = 0.9909
y = 1.4333x
R² = 0.9956
0
5
10
15
20
25
30
0246810
Δ (h)
x0(AU)
0.67/1 L 1/1 L
3/1 L 6/1 L
y = 66.702x - 48.9
R² = 0.9638
y = 35.968x - 20.9
R² = 0.7093
y = 15.125x - 11.55
R² = 0.7661
y = 8.0846x - 7.1
R² = 0.862
-10
20
50
80
110
140
170
0 5 10 15 20
ΔQ (J/g)
x0(AU)
0.67/1 M 1/1 M 3/1 M 6/1 M
y = 6.0289x - 5.95
R² = 0.2391
y = 11.418x - 5.7
R² = 0.1702
y = 34.897x - 19.2
R² = 0.7862
y = 18.666x - 18.67
R² = 0.7417
-10
20
50
80
110
140
170
0246810
ΔQ (J/g)
x0(AU)
0.67/1 L 1/1 L
3/1 L 6/1 L
Figu e 7. Re a da ion o hyd a ion o he main peak in di ec addi ion ( op g aphs) and educ ion
o hyd a ion hea o he main peak in delayed addi ion (bo om g aphs) as a unc ion o dosage o
ca boxylic g oups o PCEs o se ies M (le side) and L ( igh side) wi h di e en MAA/PEGMA
mol a ios.
Ma e ials 2024, 17, x FOR PEER REVIEW 10 o 12
(see Figu e 3 and slopes in Figu e 4). This diffe ence may be ela ed o he change in su -
ace a ea ha occu ed be o e he addi ion o he PCE in delayed addi ion. I is known
ha when C
3
S o C
3
A come in o con ac wi h wa e , pi s a e p oduced on he su ace [20–
22], esul ing in an inc ease in he o al su ace a ea as i is displayed in Figu e 8. This was
con i med in his wo k by measu ing he BET su ace a ea o he OPC as ecei ed and
a e blending he OPC and wa e o 30 min and quenching hyd a ion and measu ing he
su ace a ea again. The su ace a ea inc eased by 35% a e 30 min o hyd a ion. Due o
his inc ease, he same amoun o PCE will ha e mo e a ea o co e in delayed addi ion.
The e o e, he hea eleased du ing he hyd a ion expe imen s unde delayed addi ion do
no show a delay, bu hey show a educed hyd a ion a e because no all he pi s a e
blocked; hence, hyd a ion occu s, bu a a lowe a e because he e a e less si es a ailable
o hyd a ion. Due o he ela i ely sho delay ime (5 min), i is likely ha he C
3
A phase
was signi ican ly mo e hyd a ed han he C
3
S phase; howe e , as he C
3
A con en in he
OPC used in his wo k is much lowe han he C
3
S con en (6.8% s. 48%), he con ibu ion
o bo h mine al phases should be conside ed.
Figu e 8. Schema ic ep esen a ion o a C
3
S c ys al and i s hyd a ion when PCEs a e p esen om
he beginning o hyd a ion (di ec addi ion) and when PCEs we e added a e hyd a ion s a s (de-
layed addi ion).
4. Conclusions
In his wo k, he effec s o wo diffe en PCE addi ion me hods (di ec and delayed)
we e analysed and compa ed in e ms o he hyd a ion o a comme cial OPC. As pub-
lished p e iously, a linea dependency be ween he e a da ion o hyd a ion and he mi-
c os uc u e o he used PCEs was obse ed when PCEs we e added h ough a di ec ad-
di ion me hod. Con e sely, when PCEs we e added h ough a delayed addi ion me hod,
no e a da ion in hyd a ion was no iced. Howe e , he a e o hyd a ion was dec eased,
gi ing a educ ion in hyd a ion. Due o he educed hea o hyd a ion o he C
3
S peak, ∆𝑄
was used in he same way ha ∆𝑡 was used in he li e a u e [3]. ∆𝑄 was de ined as he
eleased hea diffe ence o he i s hyd a ion peak be ween he samples wi h and wi hou
a PCE addi ion.
The educ ion o he hea o he C
3
S peak was analysed o e he ca boxyla e dosage,
whe e diffe en esul s we e obse ed o bo h se ies. While he M se ies showed a linea
dependence in all he MAA/PEGMA mola a ios, in he L se ies almos no educ ion in
hyd a ion was seen, al hough a diffe ence was obse ed in he hyd a ion kine ics. Conse-
quen ly, ∆𝑄 canno be used o a ionalise he effec s ha PCEs wi h diffe en mic os uc-
u es ha e on hyd a ion.
The ac ha hyd a ion is no affec ed by he addi ion mode o he PCE in a model
cemen [3], and on he con a y, he hyd a ion is subs an ially affec ed in comme cial OPC
Figu e 8. Schema ic ep esen a ion o a C
3
S c ys al and i s hyd a ion when PCEs a e p esen om
he beginning o hyd a ion (di ec addi ion) and when PCEs we e added a e hyd a ion s a s
(delayed addi ion).