Ci a ion: Co , M.; Mijas, G.;
P ie o-Fuen es, R.; Riba-Moline , M.;
Cayuela, D. The In luence o Ti anium
Dioxide (TiO2) Pa icle Size and
C ys alline Fo m on he
Mic os uc u e and UV P o ec ion
Fac o o Polyes e Subs a es.
Polyme s 2024,16, 475. h ps://
doi.o g/10.3390/polym16040475
Academic Edi o : Ya osla O.
Mezhue
Recei ed: 17 Decembe 2023
Re ised: 19 Janua y 2024
Accep ed: 2 Feb ua y 2024
Published: 8 Feb ua y 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/).
polyme s
A icle
The In luence o Ti anium Dioxide (TiO2) Pa icle Size and
C ys alline Fo m on he Mic os uc u e and UV P o ec ion Fac o
o Polyes e Subs a es
Ma ía Co 1, Gab iela Mijas 1,2,3 , Remedios P ie o-Fuen es 1, Ma a Riba-Moline 1,2 and Diana Cayuela 1,2,*
1Te assa Ins i u e o Tex ile Resea ch and Indus ial Coope a ion (INTEXTER), Uni e si a Poli ècnica de
Ca alunya (UPC), 08222 Te assa, Spain
2Depa men o Ma e ials Science and Enginee ing (CEM), Uni e si a Poli ècnica de Ca alunya (UPC),
08222 Te assa, Spain
3Fundación Asociación de Beca ios Re o nados EC (ABREC), Qui o 170518, Ecuado
*Co espondence: [email p o ec ed]
Abs ac : The inclusion o pa icles in a polyme ic subs a e o achie e ce ain p ope ies is a well-
known p ac ice. In he case o ex ile subs a es, his p ac ice may deeply a ec he s uc u e o he
p oduced ya ns, as e en a ilamen wi h no ex ile applica ions can be ob ained. In his manusc ip ,
i anium dioxide (TiO
2
) pa icles we e inco po a ed in o polyes e (PET) chips and he in luence
o hese ille s on he p ope ies o ya n and ab ic, and he ul a iole p o ec ion ac o (UPF) was
assessed. Fo his pu pose, u ile and ana ase c ys alline o ms o TiO
2
, as well as he size o he
pa icles, we e e alua ed. Mo eo e , pa ame e s such as mechanical p ope ies, o ien a ion o he
mac omolecules and he mal beha io we e analyzed o ensu e ha he ex ile g ade is main ained
h oughou he p oduc ion p ocess. The esul s showed ha he inclusion o mic o- and nanopa icles
o TiO
2
dec eases he molecula weigh and enaci y o PET. Also, al hough o ien a ion and c ys allini y
a ied du ing he ex ile p ocess, he esul ing hea se ab ics did no p esen impo an di e ences in
hose pa ame e s. Finally, he a ainmen o ex ile-g ade PET-TiO
2
ab ics wi h UPF indexes o 50+
wi h bo h u ile and ana ase and mic o- and nano-sized TiO2 o ms was demons a ed.
Keywo ds: ul a iole p o ec ion ac o (UPF); i anium dioxide (TiO
2
); ana ase; u ile; polye hylene
e eph hala e (PET); POY mul i ilamen ; di e en ial scanning calo ime e (DSC); c ys allini y; kni ed
ab ic
1. In oduc ion
In ecen yea s, he e has been a signi ican su ge in he applica ion o nano echnology
wi hin he ex ile indus y, pa icula ly in he ealm o inco po a ing subs ances o enhance
unc ionali y [
1
]. Fo example, sil e nanopa icles ha e been used o p o ide an ibac e ial
p ope ies [
2
], i anium dioxide (TiO
2
) o block UV ays [
3
], and zinc oxide (ZnO) o
sel -cleaning [
4
]. The con en ional me hods used o apply hese subs ances ha e been
su ace ea men s, which p o ide ab ics wi h di e en p ope ies in a sa is ac o y mode
bu , occasionally, hey do no ha e pe manen e ec s, and he subs a es lose hei unc ion
a e washing o a ce ain usage ime. In mos cases, nanopa icles ha e been added as a
inishing p ocess in he ex ile chain, al hough a emp s ha e been made o inco po a e
hem in ea lie s ages, such as spinning, using he wis ing o ibe s in he ya n o e ain he
nanopa icles inside. Va ious publica ions ha e discussed he applica ion o nanopa icles
by deposi ing hem on he su ace o ibe s o modi y some o hei p ope ies [
5
–
9
]. The
inclusion o ille s du ing he p oduc ion o polye hylene e eph hala e (PET) ya n by a mel
spinning p ocess imp o es he quali y o he composi e, wi h he possibili y o p o iding
mo e pe manen mul i unc ional p ope ies o ex ile ma e ials. The size o hose pa icles
is a c ucial pa ame e ha de e mines he inal p ope ies o he sys em. As he size o
Polyme s 2024,16, 475. h ps://doi.o g/10.3390/polym16040475 h ps://www.mdpi.com/jou nal/polyme s
Polyme s 2024,16, 475 2 o 13
he pa icles dec eases, he e is a g ea e endency o agglome a ion and, simul aneously,
an inc ease in speci ic su ace a ea, leading o he modynamic ins abili y [
10
]. To achie e
uni o m dispe sions and a oid agg ega ion, i is essen ial o egula e hese pa ame e s
when inco po a ing pa icles in o a polyme ic ma ix. The use o dispe sing agen s is
c ucial in ensu ing homogenei y h oughou he p ocess [11,12].
Mos o he applica ions discussed in he li e a u e ocus on he u iliza ion o ce amic
nanopa icles in polyme ic ma ices, ypically in he o m o ilms o subs a es p oduced
h ough injec ion o molding p ocesses. The p oduc ion o ilamen -shaped composi es,
which exhibi unique s uc u es and p ope ies, is limi ed [
4
,
13
–
15
]. Ne e heless, he
p og ess in unc ional ibe de elopmen plays a pi o al ole in he ad ancemen o ex iles
o echnical applica ions.
Ti anium dioxide (TiO
2
) is an ino ganic, non- oxic compound, chemically s able agains
exposu e o bo h ele a ed empe a u es and UV ays, abundan , and ela i ely cheap [
16
,
17
].
Addi ionally, TiO
2
can be ob ained in a ious c ys alline o ms, such as u ile, ana ase and
b ooki e, wi h he i s wo being he mos widely used a he indus ial le el. Mo eo e ,
he ca aly ic ac i i y o TiO
2
is g ea ly enhanced when he pa icle size is lowe han
20 nm. Un o una ely, ew syn hesis echniques allow o he p oduc ion o such small
sizes (mainly pa icles < 10 nm) in a ep oducible way, limi ing he ange o he pa icles
cu en ly s udied [17,18].
P e ious s udies ha e p ima ily ocused on explo ing he dispe sion, he mal p ope ies,
mechanical p ope ies, ul a iole p o ec ion, an ibac e ial p ope ies, and o he ele an
ac o s associa ed wi h he inclusion o TiO
2
pa icles du ing he mel spinning o PET
[13–15]
.
Howe e , i is impo an o e alua e he in luence o pa icle size and polymo phism on
he a o emen ioned p ope ies. On an indus ial scale, he esul s o his s udy a e ele an
because TiO2is used as a ma ing agen in he syn hesis o plas ics and ex ile ibe s [16].
In his s udy, TiO
2
was applied o ex ile ibe s o p oduce PET ab ics ha block UV
ays, hus ob aining adia ion-p o ec i e ex iles ac oss a wide ange o wa eleng hs. Fo
his, TiO
2
was inco po a ed du ing PET spinning and he c ys alline o ms o u ile and
ana ase we e conside ed o s udy he e ec o polymo phism, ollowed by he e alua ion
o size e ec using mic o- and nano-sized pa icles. The mechanical p ope ies, o ien a ion,
c ys allini y, and he mal beha io o he ya ns p oduced we e e alua ed. Finally, kni ed
ab ics we e p oduced and he UPF and UPF index we e analyzed.
2. Expe imen al Sec ion
2.1. Ma e ials
Ti anium dioxide (TiO
2
) pa icles, la e inco po a ed in he spinning o POY PET ya ns,
we e u ile and ana ase c ys alline o ms in mic o- and nanome ic sizes supplied by Zeus
Química, S.A. (Ba celona, Spain). The cha ac e is ics o he pa icles, as p o ided by he
manu ac u e s [
19
–
22
], a e shown in Table 1and TEM images a e a ailable in a p e ious
wo k [23].
Table 1. Cha ac e is ics o TiO2pa icles.
RN RM AN AM
Comme cial e e ence
MT-500HD Tayca Co po a ion
KRONOS 2360 AMT-600 Tayca Co po a ion KRONOS 1071
Pa icle size (nm) 30 190 30 220
C ys alline o m Ru ile Ru ile Ana ase Ana ase
Speci ic su ace a ea (m
2
/g)
48 13–17 52 9–11
Composi ion
(%)
TiO2: 85
Al2O3: 1–15
Z O2: 1–10
TiO2≥92
Al2O3: 3–3.8
SiO2: 2.4–3
C: 0.18–0.2
TiO2: 80–98
TiO2≥96
Al2O3: 1–1.2
SiO2: 0.5–0.7
P2O5: 0.3–0.4
C: 0.15–0.25
Polyme s 2024,16, 475 3 o 13
The dispe sing agen used was LICOWAX E (Cla ian )( (San Joan Despí, Spain), an
es e o mon anic acids wi h mul i unc ional alcohols (MAWMA), which was ound o be
sui able o dispe sing TiO2pa icles in a PET ma ix in a p e ious wo k (Table 2) [24,25].
Table 2. Cha ac e is ics o MAWMA dispe sing agen .
Cha ac e is ics Value
Appea ance Pale yellow pelle s
Acid Index (mg KOH/g) 15–20
Saponi ica ion index (mg KOH/g) 140–160
Viscosi y (mPa·s) ~20
Densi y (23 ◦C) (g/cm3)~1.02
Pa ially o ien ed ya ns (POY) o PET mul i ilamen (48 ilamen s) con aining TiO
2
pa icles we e manu ac u ed by IQAP Mas e ba ch G oup S.L. (Masies de Roda, Spain) by
mel spinning using an ex usion empe a u e o 295
◦
C, a p essu e o 80 ba , and a winde
collec ion speed o 3000 m/min. The composi ion o hese POY including TiO
2
pa icles is
p esen ed in Table 3. In a p e ious s udy, a discon inui y in he ex usion ou low o some
mix u es wi h concen a ions o 3% TiO
2
was ound o be caused by a dec ease in iscosi y,
which p e en ed he spinning o he ya ns. Consequen ly, he p epa a ion o he ya ns had
a maximum concen a ion limi o 2% TiO
2
[
26
]. I should be no ed ha he concen a ion
o TiO
2
nanopa icles in he ya n con aining RN pa icles is lowe compa ed o ha o he
o he ya ns. This is due o he ac ha hese pa icles caused a dec ease in he iscosi y o
he PET ma ix. Consequen ly, he quan i y o nanopa icles had o be sligh ly educed in
o de o main ain he app op ia e low o polyme and ensu e he con inui y equi ed o
ya n p oduc ion.
Table 3. P ope ies o manu ac u ed POY PET ya ns.
Sample TiO2(%) Dispe sing
Agen (%)
Linea Densi y o
Non-D awn Ya n ( ex)
Linea Densi y o
D awn Ya n ( ex)
RN 1.8 1.8 26.9 17.6
RM 2 2 23.7 14.1
AN 2 2 27.4 18.3
AM 2 2 27.7 17.0
PET -- -- 28.9 15.8
2.2. T ea men s
A e spinning, he ya ns we e d awn wi h a s e ch a io o 1:2 a 190
◦
C. This
pos -spinning s e ching was applied o o ien a e he ilamen s in he di ec ion o he
ibe axis and o gi e a p ope c ys allini y, making he ya ns sui able o use as ex ile
ibe s. A e wa ds, plain kni ed ab ics we e p oduced using a ci cula kni ing machine
(90 mm and 167 needles). The a e aged cha ac e is ics o he p oduced ab ics we e as
ollows: s i ch leng h 3.23 mm/s i ch; hickness 2.24
±
0.011 mm, 16.1
±
1.0 cou ses/cm,
10.8 ±0.58 wales/cm, and 0.89 ±0.01 g/m2.
Finally, he ab ics we e hea se o he mally s abilize he subs a e. The p ocess was
pe o med in a s en e E ns Benz AG (Zü ich, Swi ze land). The hea se ing condi ions
we e a empe a u e o 190 ◦C o 1 min wi hou ension.
Polyme s 2024,16, 475 4 o 13
2.3. Cha ac e iza ion
Scanning Elec on Mic oscopy (SEM)
Mic og aphs o he ya ns we e ob ained wi h aPhenomWo ld (Eindho en,
The Ne he lands
)
800-03103-02 scanning elec on mic oscope. Samples we e p e iously Au/Pd coa ed.
Molecula weigh de e mina ion
The de e mina ion o he molecula weigh was pe o med by gel pe mea ion ch o-
ma og aphy (GPC) on a Pe kin Elme (No walk, CN, USA) 200 High Pe o mance Liquid
Ch oma og aph equipped wi h an Agilen PLgel 5
µ
m Mixed-D column 300
×
7.5 mm
p eceded by an Agilen (S ockpo , UK) Oligopo e column 6
µ
m 300
×
7.5 mm. The sys em
was calib a ed wi h Wa e s (Mil o d, CN, USA) polys y ene s anda ds, wi h an a e age
molecula weigh in he ange o 2350–200,000 g/mol. Then, 3 mg o washed ya n we e
placed in a es ube wi h 0.2 mL o o-chlo ophenol (>99%, Sigma-Ald ich, S einheim,
Ge many). A e dissol ing he ya n and cooling he ubes, 1.8 mL o chlo o o m (HPLC
g ade, s abilized wi h amylene, app ox. 150 ppm, Scha lau, Ba celona, Spain) was added
and he mix u e was s i ed. The esul ing solu ion was hen il e ed (PTFE il e , 0.45
µ
m)
and ans e ed o a ial. Analyses we e conduc ed a 40
◦
C wi h chlo o o m (HPLC
g ade, Scha lau, Ba celona, Spain) as he mobile phase a a low a e o 1 mL/min. The
To alCh om Na iga o –Tu boSEC . 6.3.1.0504 so wa e (Pe kin Elme , No walk, CN, USA)
was used o calcula e he molecula weigh in numbe , he molecula weigh in weigh ,
and polydispe si y.
Ya ns and ab ic pa ame e s
P e ious o cha ac e iza ion, he samples we e condi ioned o 48 h a 20
±
2
◦
C and
ela i e humidi y 65 ±4% acco ding o he ISO 139:2005 s anda d [27].
The linea densi y o he ya ns was de e mined acco ding o he ISO 2060:1996 s an-
da d [
28
], he su ace mass was ob ained acco ding o he UNE-EN 12127:1998 s anda d [
29
],
and he hickness was calcula ed acco ding o he ISO 5084:1997 s anda d [
30
] using a
p essu e o 100 g/cm
2
in an Adamel Lhoma gy C euso -Loi e (Le C euso , F ance) com-
p ession me e .
Dynamome ic es s we e ca ied ou in a Us e (Us e , Swi ze land) TensoKid au o-
ma ic PE 4056 equipmen , ollowing he ISO 2062:2010 s anda d [
31
] wi h a gauge leng h
o 250 mm, a es speed o 250 mm/min, p e ension o 0.5 CN/ ex, a b eaking s eng h o
80%, and 50 samples pe ya n.
De e mina ion o he o ien a ion o he molecules (sonic modulus)
Sonic modulus de e mines he molecula o ien a ion along he ibe axis. By measu ing
he speed o sound a eling longi udinally h ough he ibe , and, la e , by calcula ing he
sound modulus be o e and a e d awing he ya ns, he inc ease in molecula o ien a ion
along he ibe axis was de e mined [
32
]. A HM Mo gan Co., Inc. (Camb idge, MA, USA)
Dynamic Modulus Tes e PPM–5R was used o ha pu pose.
Di e en ial Scanning Calo ime y (DSC)
The DSC echnique was employed o de e mine he c ys allini y o he samples. A
Pe kin Elme (No walk, CN, USA) DSC7/TAC7 calo ime e was used, and he condi ions
o he expe imen we e as ollows: holding a 40
◦
C o 5 min, i s hea ing om 40
◦
C
o 300
◦
C a 20
◦
C/min, holding a 300
◦
C o 5 min, and cooling om 300
◦
C o 40
◦
C a
20 ◦C/min. Ni ogen (2 kg/cm2) was used as he pu ge gas.
In he DSC s eps, he i s hea ing was used o e alua e he mic os uc u e o he
non-d awn and d awn ya ns and o he hea se ab ics, and o de e mine he c ys allini y
om he mel ing en halpies o he samples. This i s hea ing was also used o elimina e
he he mal his o y o he polyme and, so, he s udy o he c ys alliza ion p ocess, which
solely depended on he blend and no he s uc u e, was conduc ed by ob aining cooling
he mog ams in all ins ances. To calcula e he o al mel ing en halpies (
∆HT)
and a oid
baseline e o s, he me hodology de ailed by Cayuela e al. [
33
] was applied. A pu e PET
Polyme s 2024,16, 475 5 o 13
he mog am was sub ac ed om he he mog am ob ained om each o he samples con-
aining pa icles and he esul ing he mog am was analyzed. Subsequen ly, he calcula ed
en halpy was added o he en halpy o he pu e polyes e subs a e in o de o ob ain
he o al mel ing en halpy (
∆HT
). Fu he mo e, he c ys allini y o ya ns was calcula ed
ollowing Equa ion (1).
α(%) = ∆HT
117.6·100 (1)
whe e 117.6 J/g is he en halpy o a pe ec polyes e c ys al. In all cases, he pe cen age o
polyes e in each blend was conside ed.
UPF de e mina ion
The UPF (UV p o ec ion ac o ) o he ab ics was measu ed on a Labsphe e (No h
Su on, NH, USA) UV T ansmi ance Analyze (UPF) and e alua ed wi h he speci ic
p og am o UV-1000F ab ics, acco ding o he AS/NZS 4399:1996 s anda d [
34
]. The
spec al ange o he ins umen was se om 250 o 450 nm wi h a 10 mm iewing beam
diame e . The e e ence o he sola spec um used was he spec al i adiance acco ding o
CIE No. 85 measu ed in Albuque que a noon on 3 July.
3. Resul s and Discussion
Ini ially, mic og aphs o he d awn ya ns we e cap u ed o de e mine whe he any
a ia ions could be iden i ied among he samples (Figu e 1).
Polyme s 2024, 16, x FOR PEER REVIEW 5 o 13
calcula ed en halpy was added o he en halpy o he pu e polyes e subs a e in o de o
ob ain he o al mel ing en halpy (∆𝐻). Fu he mo e, he c ys allini y o ya ns was calcu-
la ed ollowing Equa ion (1).
𝛼 (%) = ∆𝐻
117.6 · 100 (1)
whe e 117.6 J/g is he en halpy o a pe ec polyes e c ys al. In all cases, he pe cen age o
polyes e in each blend was conside ed.
UPF de e mina ion
The UPF (UV p o ec ion ac o ) o he ab ics was measu ed on a Labsphe e (No h
Su on, NH, USA) UV T ansmi ance Analyze (UPF) and e alua ed wi h he speci ic p o-
g am o UV-1000F ab ics, acco ding o he AS/NZS 4399:1996 s anda d [34]. The spec al
ange o he ins umen was se om 250 o 450 nm wi h a 10 mm iewing beam diame e .
The e e ence o he sola spec um used was he spec al i adiance acco ding o CIE No.
85 measu ed in Albuque que a noon on July 3.
3. Resul s and Discussion
Ini ially, mic og aphs o he d awn ya ns we e cap u ed o de e mine whe he any
a ia ions could be iden i ied among he samples (Figu e 1).
Figu e 1. SEM images o (a) PET, (b) PET-RN, (c) PET-RM, (d) PET-AN, and (e) PET-AM.
No no iceable a ia ions we e obse ed be ween he plain polyes e and he polyes e
con aining TiO2 pa icles. This sugges s ha he pa icles we e e enly dis ibu ed wi hin
he ibe , indica ing he effec i e ole o he MAWMA dispe sing agen . Con e sely, he
a e age molecula weigh in numbe (𝑀




), in weigh ( 𝑀




), and he polydispe si y
(𝑀




/𝑀




) o he ya ns we e measu ed o assess any changes in he polyme ic subs a e
(Table 4).
Table 4. Values o 𝑴𝒏




, 𝑴𝒘





and polydispe si y o he ya ns.
Sample 𝑴𝒏




(kg/mol)
𝑴𝒘





(kg/mol)
Polydispe si y
(𝑴𝒘





/𝑴𝒏




)
PET-RN 21.0 42.9 2.0
PET-RM 23.0 45.1 2.0
Figu e 1. SEM images o (a) PET, (b) PET-RN, (c) PET-RM, (d) PET-AN, and (e) PET-AM.
No no iceable a ia ions we e obse ed be ween he plain polyes e and he polyes e
con aining TiO
2
pa icles. This sugges s ha he pa icles we e e enly dis ibu ed wi hin he
ibe , indica ing he e ec i e ole o he MAWMA dispe sing agen . Con e sely, he a e age
molecula weigh in numbe (
Mn
,
in
weigh (
Mw
), and he polydispe si y (
Mw
/
Mn
) o
he ya ns we e measu ed o assess any changes in he polyme ic subs a e (Table 4).
The esul s showed ha he inco po a ion o ce amic pa icles caused a dec ease in
he molecula weigh o he subs a e. Fo he same manu ac u ing p ocess, PET nanocom-
posi es show a educ ion in hei in insic iscosi y and, consequen ly, in hei molecula
weigh compa ed o he pu e polyme , which means ha hese ma e ials a e mo e sensi i e
o deg ada ion as a esul o hea ing, high shea a es and esidence imes du ing he
ex usion p ocess [
35
,
36
]. Compa ing he TiO
2
-con aining ya ns, PET-RM, PET-AM and

Polyme s 2024,16, 475 6 o 13
PET-AN exhibi ed e y simila
Mn
alues. In con as , he PET-RN sample had he lowes
alues o
Mn
and
Mw
. Du ing he p oduc ion o he composi es, a dec ease in iscosi y was
obse ed, leading o a necessa y dec ease in he concen a ion o u ile- ype nanopa icles
in he mix u e. The polydispe si y alues o all samples we e ound o be 2.0, which is in
acco dance wi h he in o ma ion a ailable in he bibliog aphy [35,37].
Table 4. Values o Mn,Mwand polydispe si y o he ya ns.
Sample Mn
(kg/mol)
Mw
(kg/mol)
Polydispe si y
(Mw/Mn)
PET-RN 21.0 42.9 2.0
PET-RM 23.0 45.1 2.0
PET-AN 23.3 46.7 2.0
PET-AM 23.2 44.4 2.0
PET 27.6 51.5 2.0
The he mal beha io o he samples was assessed using he Di e en ial Scanning
Calo ime y (DSC) echnique. This analysis is c ucial in es ablishing he e ec i e empe -
a u e ange o p ocessing pu poses. By examining he he mog ams ob ained om all
samples, he empe a u e o c ys alliza ion (T
c
) and he en halpy o c ys alliza ion (
∆
H
c
)
we e de e mined using he me hodology de eloped by Cayuela e al. [33] (Table 5).
Table 5. Tempe a u e and en halpy o c ys alliza ion om mel ing o mix u es.
Sample Tc
(◦C)
∆Hc
(J/g)
PET-RN 202.8 −52.4 ±0.2
PET-RM 205.3 −52.7 ±1.2
PET-AN 206.3 −52.9 ±0.4
PET-AM 206.3 −54.7 ±0.4
PET 200.3 −48.4 ±0.3
Many impo an p ope ies o polyes e s depend on he nuclea ion p ocess, in which
he p ima y nuclei o he c ys al a e o med. This phenomenon can be homogeneous i he
molecula mo emen s o he polyme in he mol en s a e cause he alignmen o a su icien
numbe o segmen s o he chain o ollow a mo e s able o m; o he e ogeneous i he
nuclei a e o med om he simple con ac o he subs ance wi h he con aine o om
insoluble mic oscopic pa icles andomly dis ibu ed in he ma e ial [
38
]. In he p esen
case, TiO
2
pa icles ac ed as he e ogeneous c ys alliza ion nuclei, shi ing he c ys alliza ion
empe a u e owa ds highe alues. In his con ex , he ana ase o m showed a highe
c ys alliza ion empe a u e, which mean a g ea e nuclea ion powe compa ed o he u ile
o m. Conc e ely, PET-AM was he sample wi h he highes alue, wi h a c ys alliza ion
empe a u e o 206.3 ◦C and a c ys alliza ion en halpy o −54.7 ±0.4 J/g.
The mechanical p ope ies equi ed o a ibe o ha e ex ile quali ies a e achie ed
h ough he d awing p ocess. Hence, dynamome ic es s we e conduc ed on he ya ns
be o e and a e his p ocess (Table 6).
In all ins ances, a educ ion in he alues o lineal densi y was obse ed a e he
d awing p ocess. Ne e heless, no co ela ion could be es ablished among he size, he
polymo phism o he pa icles and he men ioned pa ame e , p obably due o he e ec o
he dispe sing agen , which p o ides a plas icizing e ec o he mac omolecula chains. In
gene al, he enaci y and elonga ion sligh ly dec eased a e he inco po a ion o pa icles.
A mo e comp ehensi e unde s anding o hese changes was ob ained by examining he
s ess–s ain cu es (Figu e 2).
Polyme s 2024,16, 475 7 o 13
Table 6. Lineal densi y and enaci y alues o non-d awn and d awn ya ns.
Sample Lineal Densi y ( ex) Tenaci y (cN/d ex) Elonga ion (%)
Non-D awn D awn Non-D awn D awn Non-D awn D awn
PET-RN 26.9 17.6 1.14 ±0.12 1.4 ±0.2 150.9 ±9.2 20.6 ±3.9
PET-RM 23.7 14.1 1.25 ±0.11 2.8 ±0.2 140.1 ±7.2 17.5 ±2.4
PET-AN 27.4 18.3 1.32 ±0.12 1.8 ±0.3 148.7 ±6.1 27.2 ±4.7
PET-AM 27.7 17.0 1.18 ±0.10 2.6 ±0.2 140.3 ±6.2 21.5 ±2.1
PET 28.9 15.8 1.73 ±0.11 3.5 ±0.1 149.5 ±8.2 27.6 ±2.3
Polyme s 2024, 16, x FOR PEER REVIEW 7 o 13
PET 28.9 15.8 1.73 ± 0.11 3.5 ± 0.1 149.5 ± 8.2 27.6 ± 2.3
In all ins ances, a educ ion in he alues o lineal densi y was obse ed a e he
d awing p ocess. Ne e heless, no co ela ion could be es ablished among he size, he
polymo phism o he pa icles and he men ioned pa ame e , p obably due o he effec
o he dispe sing agen , which p o ides a plas icizing effec o he mac omolecula chains.
In gene al, he enaci y and elonga ion sligh ly dec eased a e he inco po a ion o pa i-
cles. A mo e comp ehensi e unde s anding o hese changes was ob ained by examining
he s ess–s ain cu es (Figu e 2).
Figu e 2. S ess–s ain cu es o (a) non-d awn and (b) d awn ya ns.
When compa ed o he es , he ya n wi hou pa icles exhibi ed a highe modulus
and g ea e ensile s eng h. The inclusion o he pa icles dec eased he esis ance o he
ya n, al hough he elonga ion was almos he same. Fu he mo e, i was obse ed ha
ya ns wi h ana ase TiO2 had be e esis ance p ope ies han ya ns wi h u ile pa icles.
The ya ns subjec ed o he d awing p ocess dec eased in esis ance wi h espec o he
non-d awn ya ns. The dec ease in magni ude was mo e signi ican when nano-sized pa -
icles we e p esen a he han mic o-sized pa icles ega dless o he c ys alline o m. In
addi ion, he p esence o nanopa icles esul ed in a highe elonga ion a b eak. This can
be a ibu ed o he smalle sizes o hese pa icles, which caused a educed obs acle effec
compa ed o he mic opa icles.
In gene al, he enaci y o he ya ns wi h pa icles was ound o be lowe compa ed
o he enaci y o pu e PET ya n. P e ious in es iga ions ha e indica ed ha when he
quan i y o ce amic pa icles, speci ically TiO2, in Nylon ya ns exceeds 0.33%, he e is a
dec ease in he ensile s eng h. This educ ion can be a ibu ed o he p esence o high
pa icle concen a ions, in his case anging om 1.8 w .% o 2 w .%, which could lead o
in e ac ions and agglome a ions. Consequen ly, he con ac su ace be ween he pa icles
and he ma ix is educed. Fu he mo e, hese pa icles can also se e as si es o s ess
concen a ion. As a esul , when he ma e ial is subjec ed o ensile de o ma ion, he la ge
pa icles induce highe s ess concen a ions in he ma ix, leading o a dec ease in impac
ene gy. This ul ima ely causes he ma e ial o b eak ea lie han expec ed [39–41].
The enaci y alues o he ya ns wi h mic opa icles we e highe han hose o ya ns
wi h nanopa icles, wi h hese diffe ences being mo e e iden a e d awing. This inding
was co ela ed wi h he p e iously obse ed dec ease in molecula weigh alues in he
p esence o pa icles. Despi e he dec ease in he mechanical p ope ies, he enaci y al-
ues we e s ill sui able o ex ile applica ions.
The ya ns con aining mic opa icles exhibi ed g ea e enaci y alues in compa ison
o he ya ns con aining nanopa icles. The dispa i ies be ween hese wo ypes o ya ns
became mo e appa en a e unde going he d awing p ocess. This ou come can be
Figu e 2. S ess–s ain cu es o (a) non-d awn and (b) d awn ya ns.
When compa ed o he es , he ya n wi hou pa icles exhibi ed a highe modulus and
g ea e ensile s eng h. The inclusion o he pa icles dec eased he esis ance o he ya n,
al hough he elonga ion was almos he same. Fu he mo e, i was obse ed ha ya ns wi h
ana ase TiO
2
had be e esis ance p ope ies han ya ns wi h u ile pa icles. The ya ns
subjec ed o he d awing p ocess dec eased in esis ance wi h espec o he non-d awn
ya ns. The dec ease in magni ude was mo e signi ican when nano-sized pa icles we e
p esen a he han mic o-sized pa icles ega dless o he c ys alline o m. In addi ion, he
p esence o nanopa icles esul ed in a highe elonga ion a b eak. This can be a ibu ed
o he smalle sizes o hese pa icles, which caused a educed obs acle e ec compa ed o
he mic opa icles.
In gene al, he enaci y o he ya ns wi h pa icles was ound o be lowe compa ed
o he enaci y o pu e PET ya n. P e ious in es iga ions ha e indica ed ha when he
quan i y o ce amic pa icles, speci ically TiO
2
, in Nylon ya ns exceeds 0.33%, he e is a
dec ease in he ensile s eng h. This educ ion can be a ibu ed o he p esence o high
pa icle concen a ions, in his case anging om 1.8 w .% o 2 w .%, which could lead o
in e ac ions and agglome a ions. Consequen ly, he con ac su ace be ween he pa icles
and he ma ix is educed. Fu he mo e, hese pa icles can also se e as si es o s ess
concen a ion. As a esul , when he ma e ial is subjec ed o ensile de o ma ion, he la ge
pa icles induce highe s ess concen a ions in he ma ix, leading o a dec ease in impac
ene gy. This ul ima ely causes he ma e ial o b eak ea lie han expec ed [39–41].
The enaci y alues o he ya ns wi h mic opa icles we e highe han hose o ya ns
wi h nanopa icles, wi h hese di e ences being mo e e iden a e d awing. This inding
was co ela ed wi h he p e iously obse ed dec ease in molecula weigh alues in he
p esence o pa icles. Despi e he dec ease in he mechanical p ope ies, he enaci y alues
we e s ill sui able o ex ile applica ions.
The ya ns con aining mic opa icles exhibi ed g ea e enaci y alues in compa ison
o he ya ns con aining nanopa icles. The dispa i ies be ween hese wo ypes o ya ns be-
Polyme s 2024,16, 475 8 o 13
came mo e appa en a e unde going he d awing p ocess. This ou come can be a ibu ed
o he dec ease in molecula weigh alues ha we e p e iously obse ed when pa icles
we e p esen . Despi e he decline in mechanical p ope ies, he enaci y alues emained
sui able o use in ex ile applica ions.
The sonic module echnique enables he de e mina ion o he speed a which sound o
a pulse passes longi udinally h ough a ibe . This is use ul o de e mine he o ien a ion o
molecules since a highe speed co esponds o a g ea e o ien a ion and alue o he sonic
module (Table 7).
Table 7. Sonic modulus and c ys allini y o s udied ya ns.
Sample Sonic Modulus C ys allini y (%)
Non-D awn D awn Non-D awn D awn Hea se Fab ic
PET-RN 28.4 ±0.2 86.2 ±0.5 6.5 50.9 52.0
PET-RM 27.4 ±1.5 106.6 ±6.7 6.0 47.4 51.0
PET-AN 28.0 ±2.0 91.0 ±4.6 7.7 51.0 52.0
PET-AM 28.1 ±0.8 106.7 ±7.2 11.7 49.7 54.9
PET 26.1 ±0.7 106.2 ±6.1 8.0 47.1 53.5
The esul s indica ed ha ega dless o he p esence and ype o pa icles, he non-
d awn ya ns exhibi ed simila o ien a ion alues. Ne e heless, he d awn ya ns demon-
s a ed wo dis inc beha io s: he o iginal PET and he mic opa icle-con aining ya ns
displayed simila o ien a ion alues, which we e highe han hose o he nano-sized
coun e pa s. These indings can be linked o he alues ob ained om he dynamome ic
assay, pa icula ly he g ea e elonga ion esponse obse ed in ya ns con aining nano-
sized pa icles. The nanome ic size o he pa icles po en ially led o a highe deg ee
o in e locking wi hin he polyme ic ma ix, consequen ly hinde ing he o ien a ion o
molecules o a g ea e ex en . Mo eo e , his esul was consis en wi h he obse ed
enaci y, indica ing ha ya ns wi h mic opa icles exhibi ed highe enaci y compa ed o
ya ns wi h nanopa icles.
Rega ding he c ys allini y o non-d awn ya ns (Table 7), no ably, all he subs a es ex-
amined showed no signi ican a ia ions, excep o he PET-AM sample, which displayed
a highe le el o c ys allini y. I is wo h no ing ha he mog ams o und awn ibe s gene -
ally exhibi ed dis inc he mal ansi ions. The i s ansi ion is cha ac e ized by a change
in hea lux (hea capaci y, c
p
) co esponding o he glass ansi ion (Tg) egion. This egion
is associa ed wi h he empe a u e a which he mobili y o he polyme mac omolecules
begins in he amo phous zone o he ibe . This ansi ion co esponds o he amo phous
ac ion in a iphasic model o he ibe . Subsequen ly, an exo he mic peak is obse ed,
indica ing cold c ys alliza ion. This peak is ela ed o he mesophase o he model, which
ep esen s he ac ion o mac omolecules ha a e o de ed. By applying ene gy in he o m
o empe a u e, hese mac omolecules can c ys allize due o hei mo emen caused by
he mal agi a ion. Finally, he mel ing endo he m obse ed in he non-d awn polyes e
he mog ams indica es he mel ing o bo h he o iginal c ys alli es and hose o med du ing
he cold c ys alliza ion ansi ion.
The he mog ams o he d awn samples did no display any dis inc egions co e-
sponding o he glass ansi ion empe a u e (Tg) o cold c ys alliza ion (Figu e 3). The
p ocess o d awing he ibe leads o he alignmen o mac omolecules along he ibe
axis, he eby inducing a c ys alliza ion p ocess. As a esul , he in ensi y o he mal ansi-
ions associa ed wi h he amo phous po ion o he polyme dec eases. Addi ionally, his
alignmen o mac omolecules in an ex ended s a e may acili a e he app oxima ion o in e -
mac omolecula chains and he o ma ion o bonds be ween g oups. Consequen ly, he
d awn ya ns exhibi signi ican ly highe c ys allini y ( i e o eigh imes highe , depending
Polyme s 2024,16, 475 9 o 13
on he case) compa ed o hei p ecu so s, in acco dance wi h he inc eased o ien a ion
indica ed by he sonic modulus esul s.
Polyme s 2024, 16, x. h ps://doi.o g/10.3390/xxxxx www.mdpi.com/jou nal/polyme s
Figu e 3. The mog ams co esponding o (le ) he mal ansi ions o und awn ibe s and ( igh ) d awn
ibe s.
Once he p oduc ion p ocess was comple ed, he kni ed ab ics unde wen hea se
(Figu e 4). The e alua ion o he impac o hea se ing on c ys allini y (Table 7) indica ed
no signi ican a ia ions among he di e en samples. This sugges s ha he he mome-
chanical ea men s applied o he ibe s, such as sh inkage and hea se ing, in o de o
con e ex ile p ope ies o he TiO
2
-con aining ya ns, esul ed in a inal p oduc wi h
equi alen ex ile p ope ies. Consequen ly, he inclusion o TiO
2
pa icles du ing he
spinning p ocess al e ed he mic os uc u e o he ini ial ya ns, bu hese di e ences we e
elimina ed du ing subsequen p oduc ion p ocesses, leading o he a ainmen o ab ics
wi h compa able s uc u es ha can be dyed and inished unde s anda d condi ions o
con en ional polyes e .
Polyme s 2024, 16, x FOR PEER REVIEW 9 o 13
Figu e 3. The mog ams co esponding o (le ) he mal ansi ions o und awn ibe s
and ( igh ) d awn ibe s.
Once he p oduc ion p ocess was comple ed, he kni ed ab ics unde wen hea se
(Figu e 4). The e alua ion o he impac o hea se ing on c ys allini y (Table 7) indica ed
no signi ican a ia ions among he diffe en samples. This sugges s ha he he mome-
chanical ea men s applied o he ibe s, such as sh inkage and hea se ing, in o de o
con e ex ile p ope ies o he TiO2-con aining ya ns, esul ed in a inal p oduc wi h
equi alen ex ile p ope ies. Consequen ly, he inclusion o TiO2 pa icles du ing he
spinning p ocess al e ed he mic os uc u e o he ini ial ya ns, bu hese diffe ences we e
elimina ed du ing subsequen p oduc ion p ocesses, leading o he a ainmen o ab ics
wi h compa able s uc u es ha can be dyed and inished unde s anda d condi ions o
con en ional polyes e .
Figu e 4. Kni ed ab ics a he en ance o he s en e .
The UPF and UPF index o kni ed ab ic we e de e mined, and he co esponding
esul s a e p esen ed in Table 8.
Table 8. UPF alues o he hea se ab ics.
Fab ic UPF UPF Index
PET-RN 108 50+
PET-RM 165 50+
PET-AN 66 50+
PET-AM 105 50+
PET 33 30
All ab ics wi h pa icles exhibi ed a signi ican imp o emen in he UPF alue com-
pa ed o he alue o pu e PET ab ic. I was ound ha he ab ic wi h PET-RM had he
highes UPF alue, sugges ing ha he u ile o m had a g ea e p o ec i e effec han he
Figu e 4. Kni ed ab ics a he en ance o he s en e .
The UPF and UPF index o kni ed ab ic we e de e mined, and he co esponding
esul s a e p esen ed in Table 8.
Table 8. UPF alues o he hea se ab ics.
Fab ic UPF UPF Index
PET-RN 108 50+
PET-RM 165 50+
PET-AN 66 50+
PET-AM 105 50+
PET 33 30