Functional Aromatic Polyamides

44 Pages·2017·8.22 MB·English

polymers
Review
Functional Aromatic Polyamides
JoséA.RegleroRuiz ID,MiriamTrigo-López,FélixC.GarcíaandJoséM.García* ID
DepartamentodeQuímica,FacultaddeCiencias,UniversidaddeBurgos,PlazadeMisaelBañueloss/n,
09001Burgos,Spain;[email protected](J.A.R.R.);[email protected](M.T.-L.);[email protected](F.C.G.)
* Correspondence:[email protected];Tel.:[phone];Fax:[phone]
Received:13August2017;Accepted:1September2017;Published:5September2017
Abstract: Wedescribehereinthestateoftheartfollowingthelast8yearsofresearchintoaromatic
polyamides,whollyaromaticpolyamidesoraramids. Thesepolymersbelongtothefamilyofhigh
performancematerialsbecauseoftheirexceptionalthermalandmechanicalbehavior. Commercially,
theyhavebeentransformedintofibersmainlyforproductionofadvancedcomposites,paper,andcut
and fire protective garments. Huge research efforts have been carried out to take advantage of
thementionedcharacteristicsinadvancedfieldsrelatedtotransportapplications,opticallyactive
materials, electroactive materials, smart materials, or materials with even better mechanical and
thermalbehavior.
Keywords: aromatic polyamides; aramids; high-performance polymers; functional polymers;
advancedmaterials
1. Introduction
Aromatic polyamides, wholly aromatic polyamides, or the shorter form aramids, stand for
synthetic polyamides comprised >85% by amide groups (–CO–NH–) bound directly to two
aromaticrings[1]. Thesepolymersarecategorizedashigh-performancematerialsbecauseoftheir
outstanding mechanical strength and superior high thermal resistance. They are spun into fibers
foradvancedfabricssuchasadvancedsportandworkprotectiveclothing,bullet-proofbodyarmor,
advancedcompositesinarmamentandaerospaceindustries,incompositesasasbestossubstitutes,
high-temperatureinsulationpaper,tonamebutafew[2].
Thestructureofthearamidsisbasedontherigidaromaticamidelinkage,whichisresponsible
fortheoutstandingpropertiesofthesematerials. Highlydirectionalandefficientinterchainhydrogen
bondsareestablished,givingrisetomaterialswithhighcrystallizationtendencyandextremelyhigh
cohesiveenergydensity. Atthesametime,theyarealsoresponsibleoftheinsolubilityofthewholly
aromaticpolyamides,adrawbackthatimpairtheexpansionoftheapplicationfieldofthesematerials,
wheretheimprovementofthesolubilityisatopicofresearchinterest.
From a historical viewpoint, poly(p-benzamide) was commercialized about 50 years ago,
forashortperiod of time, under the tradename ‘Fiber B®’. It was an all-para oriented aramid,
anextremelyrigidrod-likemacromolecule, withimportanttransformationimpairments, thatwas
replacedonthemarketinthe1970decadebypoly(p-phenyleneterephthalamide)(PPTA),theunique
all-para oriented aramid commercialized nowadays. On the other hand, in 1967 was marketed
poly(m-phenylene isophthalamide) (MPIA), a less rigid and easily-transformable aramid with
impressive thermal resistance, only slightly underperforming the mechanical behavior of PPTA.
PPTAandMPIAwerediscoveredandinitiallycommercializedunderthetradenamesof‘Kevlar®’
and‘Nomex®’byDupont. Theyear1987sawthecommercializationofthethirdaramidmarketed
today, a copolymer with enhanced solubility prepared with terephthaloyl dichloride (TPC) and
p-phenylenediamine (PPD), like PPTA, and also with a diamine based on diaminodiphenyl ether
havingm-andp-orientedaminegroups(3,4(cid:48)-diaminodiphenylether(ODA)),givingrisetoanaramid
Polymers2017,9,414;doi:10.3390/polym9090414 www.mdpi.com/journal/polymers
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wwithithb obtohthm m--a anndd pp--oorriieenntteedd aarroommaattiicc rrininggs s(O(ODDAA/P/PPTPAT)A. I)t. wItaws paustp ount tohne tmhaermkeat rbkye tTebiyjinT ewijiitnh wthiet h
thteratdraedneanmaem “eT“ecThenchonrao®r”a.® T”h.eT shteruscttruurcetsu raensda snodmseo omf ethoef athraemaridam pridodpurcoedrus caerres sahroewsnh oinw TnaibnleT a1b. le1.
TTabablele1 .1.S Strturucctuturree,,a arraammididt tyyppee,, bbrraanndd nnaammeess aanndd ccoommppaannyy ooff ccoommmmeerrcciiaall aarraammididss. .

AArarmamididty tpyepe BraBnrdannda mnaemses CComompapnayny
PPPPTTAA MMPPIAIA ODOAD/PAP/TPAPTA
X Kevlar®
X Kevlar® DuPont, Wilmington, DE, United States
XX NoNmoemx®ex® DuPont,Wilmington,DE,UnitedStates
XX TwTarwoanr®on®
XX TeiTjineicjoinnceoxn®ex® TeTiejiinji,nA, Arnrhnehmem,t,h teheN Netehtehrelarlnadnsds
X X TecThencohrnao®ra®
XX HeHraecrraocnr®on® KKoloolnonIn Idnudsutsrtireise,sS, eSoeuolu,lK, Koroeraea
XX AlkAelxk®ex® HHyoysousnugn,gS, eSoeuolu,lK, Koroeraea
XX MeMtaeAtar aAmraidmYida rYna&rnT &h rTeharde®ad® SRSROOG Groruoupp,H, Heaetahtehrebrrbarea,eN, NewewS oSuotuhthW Walaelse,sA, Ausutsratrlaialia
XX TapTaarpaanr®anP®a rPaa-arar-aamraidmid YYanantatiaiT aTyahyohoA AdvdavnacnecdedM MataetreirailaslsC Co.o,.L, tLdt,dY, aYnatnatia,i,
XX NeNwestwars®taMr® eMtae-Atar-Aamraimdid ShSahnadnodnogn,gC, Chihniana
XX AraAwrainw®in® ToTroaryayC ChehmemiciaclaKl KoroeraeaIn Icn.,c.S, eSoeuolu,lK, Koroeraea
X Metaone Huvis,Seoul,Korea
X Metaone Huvis, Seoul, Korea
ThTehee xepxploloitiatatitoionno offt htheea abboovvee--mmeennttiioonneedd cchhaarraacctteerriissttiiccss ooff aarraammididss isis aa totoppici cofo fcucrurrernetn itnitnetreerset.s t.
ThTuhsu,sa, raormomataitcicp poolylyaammidideessa arreec cuurrrreennttllyy bbeeiinngg ssttuuddiieedd aass ffuunnccttiioonnaall aanndd ccuuttttiningg-e-eddggee mmaatetreirailasl sfofro r
eveevnenb ebtettetrert htheremrmaalllylya annddm meecchhaanniiccaallllyy rreessiissttaanntt ppoollyymmeerrss,, sseennssiinngg aanndd eexxttrraacctitoionn aapppplilciacatitoionns,s f,ifilmlms s
anadndm emmbermanbreasnfeosr trfaonrs potrratnaspppolircta tiaopnps,liocpattiiocanlsl,y aoctpitviecamllya teraiactlsiv,em atmeraitaelrsiawlsit, hemleactterroimalse chwaniticha l
oreleelcetcrotrmocehchroamnicicalp oror peelretciterso,chanrodmfiuc npcrtioopnearltieasr,a manidd sfuwnicthtiosnealel cateradmcihdesm wicitahl gsreoleucptesda nchdemlaitcearla l
stgrurocutuprse sa.nAd clcaoterrdailn sgtlryu,ctthuirserse. vAieccworfdoicnugsleys, othnisr erceevnietwa dfvocaunsceess ,ofnro rmece2n0t0 9a,divnandceessig, nfr,opmre 2p0a0r9a,t iionn ,
anddespigonte, nptrieaplaarpaptliiocna,t iaonnds poofttehnetsiaelm apaptelriciaaltsio.nPsr eovf itohuessed mevaetleorpiamlse. nPtrseivniotuhse dfieevldelwopemreesnutsm inm tahreiz feiedldb y
were summarized by Marchildon and by us in previously published reviews [2,3].
Marchildonandbyusinpreviouslypublishedreviews[2,3].
2.2S. ySnynththeseissisa annddP Prorocceessssiningg
2.21..1L. oLwowa nanddH HigighhT TemempepreartauturereS SoolulutitoionnS Syynntthheettiicc MMeetthhooddss
AArarmamididss aarree ssyynntthheessiizzeedd ata ta laabl asbcalsec ablye twbyo ptwroocedpurorcees:d luorwes a:ndlo hwigha ntedmhpiegrhatutreem spoeluratitounr e
somluettihoondsm. eTthheo dcosm. mTehreciaclo marmameirdcisa PlPaTraAm aindds MPPPTIAA aarned pMrepPaIAreda rfeollporwepinagr etdhef olollwo wteimngpetrhaetulroew
tesmolpuetrioantu mreestohloudt ifornomm ePtPhDod afnrdo mTPPCP,D ora nmd-pThPeCn,yolernmed-piahmeninyel e(nMePdDia)m ainnde (iMsoPphDt)haanlodyli sdoipchhltohraildoey l
di(cIPhClo)r, iduesi(nIgP C)a, upsoilnagr aapprootliacr saoplrvoetnict, sosulvcehn t,as suNch-maesthyNl--2m-peythrryoll-i2d-opnyer ro(lNidMonPe) (oNr MNP,)N-or
Nd,Nim-deitmhyeltahcyetlaamceitdaem (iDdMe A(D),M anAd), saanltds assa sltosluabsilistoyl upbroilmityoteprrso, msuocthe rass, LsiuCclh anads/oLri CClaaCnl2d. /AorromCaatCicl .
2
Adroiamciadtsic cadnia bceid ussceadn, inbseteuasde do,f itnhset emaodisotufrteh esemnsoitiisvtuityre dsieancisdit civhiltoyriddieasc, iudsicnhgl othried hesig,hu steinmgptehreatuhrige h
solution method, described by Yamazaki et al. [4]. These methods and the procedures followed for
temperaturesolutionmethod,describedbyYamazakietal.[4]. Thesemethodsandtheprocedures
the commercial preparation of aramid fibers are reported in our previous reviews and book chapters
followedforthecommercialpreparationofaramidfibersarereportedinourpreviousreviewsand
[2,5,6].
bookchapters[2,5,6].
2.22..2A. AltletrenrnataitvieveS SyynnththeteitcicM Meetthhooddss
From the organic chemistry viewpoint, the aromatic amide group can be prepared by a number
Fromtheorganicchemistryviewpoint,thearomaticamidegroupcanbepreparedbyanumber
of alternative reactions to prepare wholly aromatic polyamides [2,7–10]. However, only the
ofalternativereactionstopreparewhollyaromaticpolyamides[2,7–10]. However,onlythepreviously
previously described low and high temperature solutions methods have both demonstrated
described low and high temperature solutions methods have both demonstrated commercial and
commercial and laboratory viability in relation with the absence of side reaction and the quantitative
laboratoryviabilityinrelationwiththeabsenceofsidereactionandthequantitativeyieldrequiredfor
yield required for obtaining high molecular mass polymers. Nevertheless, among the time span
Polymers2017,9,414 3of44
obtaininghighmolecularmasspolymers. Nevertheless,amongthetimespancoveredbythisreview
andatlabscale,alternativeprocedurestotheconventionalcondensationofdiacidordiaciddichloride
and diamines have been reported. From the green chemistry viewpoint, Ueda et al. reported on
thesolid-statepreparationofaramids[11,12],andKobashietal. discussedthedirectcondensationof
aromaticdiacidsanddiaminesathightemperaturewithoutcondensationpromoters[13].
2.3. Processing
Commercialaromaticpolyamidesareprocessedintostaplefibers,continuousmultifilamentyarn,
staplefibersandpulpfromsolutionbywetspinning(MPIA,ODA/PPTAandPPTA),dryspinning
(MPIAandODA/PPTA)anddry-jetwetspinning(MPIAandODA/PPTA)[6].
3. SynthesisofFunctionalAromaticPolyamideswithControlledStructure
Forthesakeofsimplicity,itisgenerallyassumedthatallthefunctionalgroupsofthemonomers
andgrowingpolymerchainspresentsameorsimilarreactivity. Underthisassumption,conventional
polycondensation reactions occur on a step-growth manner according to Carother’s equation and
Flory’sstatisticaldescription[14]. Thecontroloverthemolecularmassandthepolymerendgroups
is difficult, and thus the molecular mass distribution approaches a value of 2 at high conversion.
However, when monomers with evident unequal reactivity are employed, or when a change of
reactivityisinducedinonefunctionalgroupbyreactionandbondformationduringpolymerizationof
otherfunctionalgroup,thepolymergrowthdonotobeytheseconventionalrules.Inordertosynthesize
a polymer with controlled molecular mass, a narrow molecular mass distribution and defined
chain-end functional groups, the condensation should proceed in a chain-growth polymerization
mannerinsteadofstep-growthpolycondensation. Thisisthecaseforso-calledlivingpolymerization.
3.1. Chain-GrowthPolycondensation
Someexperimentalresultsshowedthatitispossibletoobtainhighmolecularmasscondensation
polymers even at low conversions, contrary to Flory’s and Carother’s predictions. This opened
thewaytochain-growthpolycondensation. YokoyamaandYokozawapublishedadetailedreview
ofchain-growthpolycondensation[15,16],andamorerecentreviewaboutthelatestdevelopments
in the field [17]. Polyethers and aromatic polyamides are prepared using the unequal reactivity
inducedbyactivationoftheendgroupsofthepolymerchains. Theyfoundthatthepolycondensation
ofphenyl4-(octylamino)benzoate1a(Scheme1A,P1)andtheinitiatorphenyl4-nitrobenzoate2in
thepresenceofabaseyieldedwelldefinedaramidswithlowpolydispersity(M /M ≤1.1,where
w n
M and M are number-average and weight-average molecular masses, respectively). The fact
n w
that the M values increase with the monomer proportion can be attributed to the difference in
n
substituenteffectbetweenthemonomerandthepolymer,indicatingachain-growthpolycondensation
reaction. Theamideanion1a(cid:48),whichisformallyanABcondensationmonomer,donotpolymerize
becauseofthestrongelectron-donatingability(electron-donatinggroup—EDG)oftheamideanion.
Onthecontrary,theelectron-withdrawinggroup(EWG)nitrogroupactivatesthephenylestermoiety
in the initiator 2 through resonance effects. The reaction of 1a(cid:48) with 2 yields an amide, which is
aweakEDG,andsothemonomer1a(cid:48) reactsonlywiththemorereactivephenylesteroftheamideof
thegrowingpolymerchain,andnotwithitself. Therefore,thepolymerizationfollowsachain-growth
pattern. Goodresultswereobtainedbyusingastrongbase,suchaslithiumhexamethyldisilazide
(LiHMDS),andphenyl4-methylbenzoateastheinitiator[18]. However,whenthemonomerbears
atri(ethyleneglycol)monomethylether(TEG)sidechaininsteadofanalkylgroup,thepolymerization
isveryslowasaresultofthecoordinationoftheLicationtothenucleophilicnitrogenatomoftheside
chainandtheconcomitantreductionofthereactivityoftheamide. Thepolymerizationofthemethyl
estermonomergaveapolymerwithlowmolecularmassandbroadpolydispersity. Ontheotherhand,
themorereactivephenylestermonomeryieldedat−20◦Capolymerwithcontrolledstructure,i.e.,
controlledmolecularmassandlowpolydispersity(Scheme1B,P2)[19].
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Scheme 1. Aromatic polyamides with controlled polydispersity and mass obtained by chain-growth
Scheme1. Aromaticpolyamideswithcontrolledpolydispersityandmassobtainedbychain-growth
polycondensation. (A) polycondensation of phenyl 4-(octylamino)benzoate and the initiator phenyl
polycondensation.(A)polycondensationofphenyl4-(octylamino)benzoateandtheinitiatorphenyl
4-nitrobenzoate; (B) polycondensation of a monomer that bears a TEG sidechain; (C)
4-nitrobenzoate;(B)polycondensationofamonomerthatbearsaTEGsidechain;(C)polycondensation
polycondensation o 2,6-positions substituted naphthalenes.
o2,6-positionssubstitutednaphthalenes.
The resonance effects also work in the 1,5- or 2,6-positions of naphthalene, so Mikami et al.
The resonance effects also work in the 1,5- or 2,6-positions of naphthalene, so Mikami et al.
extended their work using this type of monomers (Scheme 1C, P3–P4) [20]. Well defined polymers
extendedtheirworkusingthistypeofmonomers(Scheme1C,P3–P4)[20]. Welldefinedpolymers
were obtained using the monomer with a 3,7-dimethyloctyl pendant group, whereas the monomer
wereobtainedusingthemonomerwitha3,7-dimethyloctylpendantgroup,whereasthemonomer
with the TEG moiety gave both chain-growth and step-growth polyamides, with self-condensation,
withtheTEGmoietygavebothchain-growthandstep-growthpolyamides,withself-condensation,
because an insufficient deactivation of the electrophilic ester moiety, rendering polymers with Mn
becauseaninsufficientdeactivationoftheelectrophilicestermoiety, renderingpolymerswithM
lower than the expected theoretical value. n
lowerthantheexpectedtheoreticalvalue.
Following this methodology, block copolymers were obtained exploiting the living-like
Following this methodology, block copolymers were obtained exploiting the living-like
polycondensation. Yokoyama et al. [21] reported a controlled synthesis of a diblock copolymer
polycondensation. Yokoyama et al. [21] reported a controlled synthesis of a diblock copolymer
composed of an aromatic polyamide and an aromatic polyether, consisting of N-alkylated poly(m-
composed of an aromatic polyamide and an aromatic polyether, consisting of N-alkylated
benzamide) and cyano and propyl substituted poly(1,4-phenylene oxide), by two successive chain-
poly(m-benzamide)andcyanoandpropylsubstitutedpoly(1,4-phenyleneoxide),bytwosuccessive
growth condensation polymerizations (Scheme 2, P5–P7). The synthetic route started with the
chain-growth condensation polymerizations (Scheme 2, P5–P7). The synthetic route started
polymerization of 3 from a monofunctional initiator, followed with the introduction of a
with the polymerization of 3 from a monofunctional initiator, followed with the introduction
fluorobenzophenone unit at the polymer terminal, and finished with the polymerization of the
of a fluorobenzophenone unit at the polymer terminal, and finished with the polymerization of
polyether monomer.
thepolyethermonomer.
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SScchheemmee 22.. BBlloocckk ppoollyymmeerrss oobbttaaiinneedd bbyy cchhaaiinn--ggrroowwtthh ppoollyyccoonnddeennssaattiioonn..
Scheme 2. Block polymers obtained by chain-growth polycondensation.
Regarding graft copolymers, Sugi et al. described a well-defined aramid grafted with
RReeggaarrddiinngg ggrraafftt ccooppoollyymmeerrss,, SSuuggii eett aall.. ddeessccrribibeedd aa wweellll--ddeeffiinneedd aarraammiidd ggrraafftteedd wwiitthh
poly(tetrahydrofuran) by chain growth polymerization of 4-aminobenzoic acid ester having a
ppoollyy((tteettrraahhyyddrrooffuurraann)) bbyy cchhaaiinn ggrroowwthth ppoolylymmeerirzizaatitoionn ofo f4-4a-maminionboebneznozioci cacaidci desetesrt erhahvainvgin ga
poly(tetrahydrofuran) residue 5a on the amino group [22]. The polymerization of monomer 5a at
apoployl(yte(ttreatrhayhdyrdorfuofruanra) nr)esriedsuideu 5ea5 oano nthteh aemaminoin ogrgoruopu p[22[2].2 ]T.hTe hpeoplyomlyemriezraitzioatni oonf omfomnoomnoemr e5ra 5aat
−10 °C was accompanied with self-polycondensation. However, polymerization of the methyl ester
a−t10− °1C0 ◦wCaws aacscaocmcopmanpiaendi ewdiwthi tshelsfe-lpf-oplyoclyocnodnednesnastaiotino.n H. Howoweveevre, rp,poolylymmeerirzizaatitoionn ooff tthhee mmeetthhyyll eesstteerr
monomer 5b at 10 °C occurred only in a chain growth manner to render a well-defined graft
mmoonnoommeerr 55bb aatt 1100 ◦°CC ooccccuurrrreedd oonnllyy iinn aa cchhaaiinn ggrroowwtthh mmaannnneerr ttoo rreennddeerr aa wweellll--ddeefifinneedd ggrraafftt
copolymer P8 with a narrow molecular mass distribution (Scheme 3, P8).
ccooppoollyymmeerr PP88 wwiitthh aa nnaarrrrooww mmoolleeccuullaarr mmaassss ddiissttrriibbuuttiioonn ((SScchheemmee 33,, PP88))..

Scheme 3. Well-defined aramid grafted with poly(tetrahydrofuran).
SScchheemmee 33.. WWeellll--ddeeffiinneedd aarraammiidd ggrraafftteedd wwiitthh ppoollyy((tteettrraahhyyddrrooffuurraann))..
Self-assembly of star polymers would also be a useful starting point to prepare nanoarchitecture
Self-assembly of star polymers would also be a useful starting point to prepare nanoarchitecture
of araSmelfi-dass,s demueb ltyo othfestiar rcpomolypmacetr sstwruocutuldrea, lgsolobbeualaur ssehfauples,t aarntidn glaprgoein stutorfapcree paarreea n[a2n3]o.a Orchhiistie cettu arle.
of aramids, due to their compact structure, globular shape, and large surface area [23]. Ohisi et al.
osyfnatrhaemsiizdesd, da usteatro ptohlyeimrecro mwipthac ctosnttrruocltluedre m, golloebcuullaarr mshaasps ea,nadn ldowla rpgoelysduirsfpaceersaitrye afo[l2lo3w].iOngh ias ichetaainl.
synthesized a star polymer with controlled molecular mass and low polydispersity following a chain
sgyronwthtehs iczoenddeanssatatironp osltyramteegryw uistihngc o3n-(tarloklyleldamminool)e-cbuelnazromic aascsida ensdtelros w(copnodlyendsisaptieorns imtyonfoolmloewr)i ning
growth condensation strategy using 3-(alkylamino)-benzoic acid esters (condensation monomer) in
athec hparinesegnrcoew othf pchonendyeln s4a-tviionnylbsternazteogayte u(scionngde3n-s(aaltkioynla miniintioa)to-bre, nvzioniyclica ccido-mesotnerosm(ecro) nadnedn sNat,iNon′-
the presence of phenyl 4-vinylbenzoate (condensation initiator, vinylic co-monomer) and N,N′-
mmoetnhoymleenre)binistahceryplraemseidncee (dofivpihneynl ycol4-m-voinnyolmbeenrz) o(Sactehe(cmone d4e, nPs9a–tPio1n5)i n[2it4ia].t or,vinylicco-monomer)and
Nm,eNth(cid:48)-ymleenthebyilseancerbyilsaamcriydlea m(diidvein(ydli vcion-ymlocnoo-mmoenr)o (mScehr)e(mSceh 4e,m Pe9–4P,1P59)– [P2145].) [24].
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Polymers 2017, 9, 414 6 of 42

SchSecmheem4e. 4S.t aSrtapr oploylmymeresrsp prerpeparaereddb byyc chhaaiinn--ggrroowwtthh ppoollyyccoonnddeennssaattiioonn//rardaidciacla clocpooplyomlyemriezraitziaotnio. n.
3.2. Constitutional Isomerism
3.2. ConstitutionalIsomerism
The different reactivity of condensation monomers arises from asymmetry (asymmetry of
The different reactivity of condensation monomers arises from asymmetry (asymmetry of
monomers or induced by reaction of one functional group). Asymmetry is due to chemically
monomers or induced by reaction of one functional group). Asymmetry is due to chemically
inequivalent functional groups on the monomer that exhibit different reaction rates or kinetics.
inequivalentfunctionalgroupsonthemonomerthatexhibitdifferentreactionratesorkinetics.
The study of the polyamides obtained from asymmetric diamines or diacid monomers (XabX)
Thestudyofthepolyamidesobtainedfromasymmetricdiaminesordiacidmonomers(XabX)has
has not been analyzed deeply. Polyamides based on asymmetrically substituted diamine monomers
notbeenanalyzeddeeply.Polyamidesbasedonasymmetricallysubstituteddiaminemonomerspresent
present unequal reactivity of functional groups, affecting thermal and mechanical properties, as
undeqesucarlibreedac tbiyv itHysoiafof uentc tailo. n[a2l5g].r oAulpsos,, aaf fgeoctoidn gdtehsecrrmipatiloann dofm theceh raenliactaiolnp rboeptewretieens ,caosndsteistucrtiibonedal by
Hsiisaoomeetrails.m[2 a5n].dA plshoy,saicgaol opdrodpeesrctireips tciaonn boef tfhoeunredl ainti othneb wetowreke onf cPoinnsot iettu atilo. n[2a6l]i.s Tohmise rwisomrka innddpichaytesdic al
prothpaetr ttihees cqaunanbteifficoautniodn ionf ththeew storrukctoufreP irneogueltaarlit.y[2 i6s] .dTefhinisedw ourskinign dthicea pterdobtahbaitlitthye oqf ufianndtiinfigca ttwioon-of
theadstjraucecntut rneorne-gsuymlarmiteytriisc duenfiitnse idn uas icnhgaitnh epopirnotbinagb iilnit ythoef sfianmdei ndgirtewctoio-and (jparcoebnatbniloitny- spyamrammeettreirc, us)n. its
inaThcehna,i na ppooliynctoinngdeinnstahteiosna mreeacdtiiorenc otifo tnw(op mroobnaobmilietrys,p sayrmammeetterric, sa)n.dT hneonn,-saypmomlyectorincd, ceanns aptrioodnurceea catnio n
ofitnwfionimte onnuommbeerr so,fs dyimsomrdeetrreidc paonldymnoerns-,s iynm wmhiecthr isc v,acraiens pbreotwdueecne 0a nanidn fi1.n Tithee nauutmhobresr aolsfod diessocrrdibeere d
poltywmo elrims,iitnedw ohridcehresdv astrriuesctbuertews eheenad0 taon tdai1l .(HTh-Te, as u=t h1)o arsndal hsoeadde tsoc rhibeaedtw/taoill itmo tiateild (Hor-dHe/rTe-dT,s str =u 0ct)u. res
headtoTthaeil r(eHac-Tti,osn= be1t)waenedn hXeaabdXt aonhde aYdcc/Yta pilrotodutaciels( Hsh-oHrt/ sTu-bT-,sstr=uc0t)u.res –acca–, –accb–, –bcca– and
–bccb– (–accb– and –bcca– are indistinguishable). Equation 1 describes the calculation of the
probability parameter s, of –accb– sub-structures, related to the other three possible structures.
Polymers2017,9,414 7of44
The reaction between XabX and YccY produces short sub-structures –acca–, –accb–, –bcca–
and –bccb– (–accb– and –bcca– are indistinguishable). Equation (1) describes the calculation of
Polymers 2017, 9, 414 7 of 42
theprobabilityparameters,of–accb–sub-structures,relatedtotheotherthreepossiblestructures.
[ ]
accb
ss==(([[aaccccaa]]++[[[aaaccccccbbb]]]++[[bbccccbb]])) (1)( 1)
RReecceennttlyly,,P Paalle etta al.l.[ [2277]]s sttuuddiieedd tthhee ccoonnssttiittuuttiioonnaall iissoommeerriissmm ooff aarroommaattiicc ppoollyyaammidideess ccoonntatainininingg
ppeennddaannttg grroouuppssb baasseedd oonn aassyymmmmeettrriiccaallllyy ssuubbssttiittuutteedd mm--pphheennyylleennee ddiiaammiinneess ((SScchheemmee 55, ,PP1166),) ,wwhheerere
ththee sseeqquueennccee ddiissttrriibbuuttiioonn ccaann bbee ananalaylzyezde danadn dprpedreicdtiecdte. dT.heT phoelypaomlyidames iwdeesrew seyrnethseysnizthedes bizye ldowby
lotewmtpeemrapteurraet uirnetienrtfearcfiaacl iaploplyoclyocnodnednesnastiaotnio noof f44--[[44--((11--mmeetthhyyll--11--pphheennyyleletthhyyl)lp)phheennooxxyy]-]1-1,3,3-d-diaiammininoo
bbeennzzeennee aanndd 44-{-4{4-[-([4(4--mmeetthhyyllpphheennyyll))ssuullpphhoonnyyll]]pphheennooxxyy}}--11,3,3--ddiaiammininoo bbeennzzeenne ewwitihth twtwoo aarroommaatitci c
ddiaiaccididc chhlolorridideess,,i issoopphhtthhaallooyyll cchhlloorriiddee aanndd tteerreepphhtthhaallooyyll cchhlloorriiddee.. TThheeyy oobbttaainineedd mmeeddiuiumm mmoolelecuculalar r
mmaassss,,e esssseennttiiaallllyy aammoorrpphhoouuss ppoollyymmeerrss,, wwiitthh ggllaassss--ttrraannssiittiioonn tteemmppeerraatuturreess inin ththee rraannggee 223377––22545 4°C◦C, ,
ggooooddt htheerrmmaall ssttaabbiilliittyy,, aanndd iimmpprroovveedd ssoolluubbiilliittyy.. TThhee ccoonnssttiittuuttiioonnaall iissoommeerriissmm wwaass ininvveesstitgigaatetded bbyy
1H1H aanndd 1133CC nnuucclleeaarr mmaaggnneettiicc rreessoonnaannccee ssppeeccttrroossccooppyy,, ffiinnddiinngg aa ccoonnssttitiututitoionnaal loordrdeer rs sinin ththee rraannggee
00.3.355––00.3.377..

SScchheemmee 55.. AArraammiidd ssuubb--ssttrruuccttuurreess oobbttaaiinneedd uussiinngg aann aassyymmmmeettrriicc AABB mmoonnoommeerr. .
The improvement of the solubility of the polyamides is still one of the main key points to
The improvement of the solubility of the polyamides is still one of the main key points to
overcome. In this sense, the main strategy consists of decreasing the rigidity of the polymer backbone,
overcome. Inthissense,themainstrategyconsistsofdecreasingtherigidityofthepolymerbackbone,
thus reducing the interchain interactions by the inhibition of the chain packing. The introduction of
thus reducing the interchain interactions by the inhibition of the chain packing. The introduction
molecular asymmetry, flexible units, or bulky pendant groups are some of them. In this regard,
ofmolecularasymmetry,flexibleunits,orbulkypendantgroupsaresomeofthem. Inthisregard,
Sadavarte et al. [28] described the phosphorylation condensation of 4-pentadecylbenzene-1,3-
Sadavarteetal.[28]describedthephosphorylationcondensationof4-pentadecylbenzene-1,3-diamine
diamine with four commercially available aromatic acids (biphenyl-4,4′dicarboxylic acid, 4,4′-
withfourcommerciallyavailablearomaticacids(biphenyl-4,4(cid:48)dicarboxylicacid,4,4(cid:48)-oxybisbenzoic
oxybisbenzoic acid, terephthalic acid and isophthalic acid). They obtained medium molecular mass
acid, terephthalic acid and isophthalic acid). They obtained medium molecular mass polymers,
polymers, showing constitutional isomerism, with improved solubility in organic solvents due to the
showingconstitutionalisomerism,withimprovedsolubilityinorganicsolventsduetothependant
pendant dodecyl chains.
dodecylchains.
Damaceanu et al. [29] also improved the solubility of polyamides by introducing asymmetry in
Damaceanuetal.[29]alsoimprovedthesolubilityofpolyamidesbyintroducingasymmetryin
the polymer structure. Their group produced high molecular mass polyamides, synthesized from
thepolymerstructure. Theirgroupproducedhighmolecularmasspolyamides, synthesizedfrom
asymmetric diamines with phenoxy-substituted benzophene segments, using some aromatic diacid
asymmetricdiamineswithphenoxy-substitutedbenzophenesegments,usingsomearomaticdiacid
chlorides containing ether, hexafluoroisopropylidene or diphenylsilane groups.
chloriAdelssoc,o pnrteavinioiunsglye,t hUeerd,ha e[x3a0]fl aunodro Giseonptriloep aynldid Seunteeor r[3d1i]p rheevnieywlseilda ntheeg croonusptsit.utional isomerism in
polyAamlsoid,ep rsetrvuioctuusrleys, Ureegdaard[3in0g] acnondsGtiteunttiiolenaaln odrdSeurt,e trh[e3o1r]yr,e avniedw peodlytahmeicdoen ssttriutucttiuornea. lisomerismin
polyamidestructuresregardingconstitutionalorder,theory,andpolyamidestructure.
3.3. Aromatic Polyamides with Spherical-Like Structures
Aromatic polyamides show outstanding mechanical, thermal, and chemical properties as a
result of their linear structure and their interchain hydrogen bonds, and thus they are considered
high performance polymers. However, they are also highly insoluble in organic solvents, intractable
and cannot be melt-processed. The inhibition of the amide-amide linkages to increase their solubility
and make them easier to melt can be achieved by means of introducing asymmetric or bulky pendant
groups, or by modification of the polymer architecture. The introduction of dendritic structure, or
Polymers2017,9,414 8of44
3.3. AromaticPolyamideswithSpherical-LikeStructures
Aromaticpolyamidesshowoutstandingmechanical,thermal,andchemicalpropertiesasaresult
of their linear structure and their interchain hydrogen bonds, and thus they are considered high
performancepolymers. However,theyarealsohighlyinsolubleinorganicsolvents,intractableand
cannotbemelt-processed. Theinhibitionoftheamide-amidelinkagestoincreasetheirsolubilityand
make them easier to melt can be achieved by means of introducing asymmetric or bulky pendant
groups, or by modification of the polymer architecture. The introduction of dendritic structure,
orsphere-likegeometry,inhibittheinterchaininteractions,leadingtoprocessablehighperformance
polymers of known molecular mass, spherical, defect free and monodisperse, with low solution
viscosity, poor mechanical properties, and good solubility [32]. These properties enable aromatic
polyamidestobeusedinbiologicalandmedicalapplications,andfornovelapplicationsrelatedto
theirencapsulationcharacteristics,chromatography,catalysis,orself-assembly.
Spherical-like aromatic polyamides can be obtained by different procedures. Dendrimers
are prepared either by convergent growth (reaction of preformed dendrons with a central core
molecule) or divergent growth (slow addition of building blocks of low molecular mass starting
fromapolyfunctionalmolecule,thecore)bytediousmultiple-stepsprocedures[33]. Thepreparation
ofhyperbranchedpolymersismucheasier,usuallyfollowingaone-potprocedureunderconventional
polymerization reactions; and they are neither monodisperse or defect-free. In addition to the
dendritic (D) and terminal (T) units present in perfect dendrimers, hyperbranched polymers also
havelinear(L)units,beingtheirstructuremonomer-dependent. Anoverviewaboutthesynthesis,
propertiesandapplicationsofthesetypesofaromaticpolyamideswaspublishedbyScholletal.[34]
andJikeiandKakimoto[32].
A more recent work by Matsumoto [35] reported the preparation of aromatic polyamide
dendrimers, using a divergent approach, up to the sixth generation with a polyhedral oligomeric
silsesquioxane(POSS).Aneight-functionalcorewaspreparedusingocta(n-propylamine)-POSSand
anAB buildingblockusing3,5-bis(trifluoroacetamido)benzoicacidanddeprotectedwithhydrazine
2
toyieldtheG1dendrimer. Therestofthedendrimers(synthesizedinasimilarway)wereobtainedin
highyieldswithouttediouspurification. Theseorganic-inorganichybridnanoparticleshavepotential
applicationinnanoscienceasfluorescentnanofillerswithcontrolledfunctionality,shapeandsize.
Tsushima and coworkers [36] also reported a much easier procedure to isolate dendrimers
comparedtotraditionalmethods.Theyperformedaone-potmultistepsynthesisbypreparingdendritic
aromaticpolyamidedendronsonaglycine-modifiedWangresinasthesolidsupport. Anyunreacted
chemicals can be removed by washing the resin with solvents, as the propagating dendrons are
attachedtotheinsolublesupport.
Aromatic and semiaromatic amine-terminated hyperbranched polyamides and carboxylic
acid-terminatedhyperbranchedpolyamide-estersweresynthesizedbyShabbirandcoworkers[37].
Theformerwerepreparedbylowtemperaturepolycondensationofanaromatictriamine(1,3,5-tris(4(cid:48)-
aminophenylcarbamoyl)benzene) (B monomer) with different A diacid chlorides (terephthaloyl
3 2
chloride, isophthaloyl chloride, sebacoyl chloride and adipoyl chloride) to render hyperbranched
polyamidessolubleinpolaraproticsolvents,withglasstransitiontemperatures(T )between138and
g
198◦Candmolecularmassesintherangeof1.3×104–2.7×104.
Fluorescentporoushyperbranchedaramidswithdifferentterminalfunctionalgroupsthrough
anA +B approachhavebeensynthesizedbyHu[38]. Heused1,3,5-tri(4-carboxylphenyl)benzene
2 3
and p-phenylenediamine to prepare polyamides with strong blue fluorescence with potential
applications in storage, separation, catalysis and light emitting. Examples of other applications
ofhyperbranchedpolyamidesaretheiruseinreverseosmosismembranes[39],(Scheme6,P17–P19),
in applications related to their magnetic properties due to the complexation of hyperbranched
polyamideswithametal[40],totheirelectrochromicpropertiesaftertheintroductionofelectroactive
units [41], or the improvement of thermal properties of composites grafted with hyperbranched
polyamides[42,43].
Polymers2017,9,414 9of44
Polymers 2017, 9, 414 9 of 42

SScchheemmee 66.. HHyyppeerrbbrraanncchheedd aarraammiiddss..
4. Aromatic Polyamides with Selected Properties and Applications
4. AromaticPolyamideswithSelectedPropertiesandApplications
44.1.1..P Poolylyaammidideessw wiitthh HHiigghh TThheerrmmaall SSttaabbiilliittyy aanndd FFllaammee--RReettaarrddaanntt PPrrooppeerrttiieess
AArarammididssa raerceo ncsoindseirdeedreadh iga hhpiegrhf orpmerafnocrmepaonlcyem perolmymainerly mfoaritnwlyo rfeoars otnwso, forreathsoenirso, uftosrt anthdeiinrg
outstanding mechanical performance and for their thermal stability and flame resistance. In this
mechanicalperformanceandfortheirthermalstabilityandflameresistance.Inthissection,wedescribe
section, we describe some of the novel structures reported in the literature during the last years.
some of the novel structures reported in the literature during the last years. Polymers with flame
Polymers with flame retardant properties usually contain halogens in their structure and some of
retardant properties usually contain halogens in their structure and some of them will also be
them will also be described later.
describedlater.
In a first group, several authors have studied the synthesis of good thermal stability fluorinated
In a first group, several authors have studied the synthesis of good thermal stability
polyamides. Jiang et al. [44] reported on the preparation of fluorine containing polyamides obtained
fluorinated polyamides. Jiang et al. [44] reported on the preparation of fluorine containing
from polycondensation of 2-(4-trifluoromethylphenoxy)terephthalic acid with four trifluoromethyl-
polyamidesobtainedfrompolycondensationof2-(4-trifluoromethylphenoxy)terephthalicacidwith
fosuubrsttirtiufltuedor aormometahtyicl- bsuisb(estthiteurt eadmianreo)ms (aStcihcebmise( e7t, hPe2r0)a. mPoinlyem)ser(sS chhaedm Tegs 7b,etPw2e0e)n. 18P9o alynmd e2r1s4 °hCa,d
Tansdb e1t0w%e emnas1s8 9losasn dtem21p4er◦aCtu,reasn dran1g0i%ngm fraosms lo47s5s ttoem 4p83e ra°Ctu. reGshareamngyi negt afrlo. m[454] 7d5estcori4b8e3 th◦eC .
g
preparation of a series of fluorescent anthraquinone-quinoxaline containing polyamides, prepared
Ghaemy et al. [45] describe the preparation of a series of fluorescent anthraquinone-quinoxaline
from an aromatic diamine, 2,3-bis(4-(4-amino-2-(trifluoromethyl) phenoxy)phenyl)naphtho[2,3-
containingpolyamides,preparedfromanaromaticdiamine,2,3-bis(4-(4-amino-2-(trifluoromethyl)
pfh]qeunionxoyx)aplhineen-y7,l1)n2-adpihontheo. [P2o,3l-yfa]qmuiidneosx halaidn eη-7in,h1 2b-edtwioeneen. 0.P3o9l yaanmd id0.e6s2 hdaLd/g,η Tgs bbeettwweeeenn 203.309 aanndd
inh
03.6223 d°LC/, ga,ndT 1s0%be mtwaeses nlo2s3s 0teamnpder3a2t3ur◦eCs ,ina nthde 1r0a%ngem oafs s36l2o stso t4e3m3 p°Cer aintu Nre2s. Sinhotchkerarvain egt ealo. f[4366]2
g
present a series of organic-soluble poly(ether-amide)s bearing sulfoxide and electron withdrawing
to 433 ◦C in N . Shockravi et al. [46] present a series of organic-soluble poly(ether-amide)s
trifluoromethyl 2group, starting from bis(ether-amide) monomer, 2,2′-sulfoxide-bis[4-methyl(2-
bearingsulfoxideandelectronwithdrawingtrifluoromethylgroup, startingfrombis(ether-amide)
trifluoromethyl)-4-aminophenoxy) phenyl ether], and several aromatic acids. The polymers could be
monomer,2,2(cid:48)-sulfoxide-bis[4-methyl(2-trifluoromethyl)-4-aminophenoxy)phenylether],andseveral
cast into flexible and tough films from DMA solutions, with Tgs between 160 and 220 °C. In addition,
aromaticacids. ThepolymerscouldbecastintoflexibleandtoughfilmsfromDMAsolutions,with
T10s%b emtwasese lnos1s6 t0emanpder2a2tu0r◦eCs .wIenrea dredciotirodne,d1 i0n% thme raasnsgleo sosf t4e0m0 ptoe r5a0t5u °rCes inw Ner2e anredc ofrrodmed 38in0 ttoh e48r0a n°Cge
ign air atmosphere. Also, Damaceanu et al. [47] prepared two different aromatic fluorinated
of 400 to 505 ◦C in N and from 380 to 480 ◦C in air atmosphere. Also, Damaceanuetal.[47]
polyamides. One of th2e polyamides contained in the main chain 1,3,4-oxadiazole and naphthalene
preparedtwodifferentaromaticfluorinatedpolyamides. Oneofthepolyamidescontainedinthemain
moieties. The other derived from an asymmetrycal diamine containing a phenoxy-substituted
chain1,3,4-oxadiazoleandnaphthalenemoieties. Theotherderivedfromanasymmetrycaldiamine
benzophenone. The obtained polyamide films showed excellent thermal stability, with starting
containingaphenoxy-substitutedbenzophenone. Theobtainedpolyamidefilmsshowedexcellent
decomposition temperatures above 400 °C. Finally, Jiang et al. [48] synthetized 9,9-bis[4-
thermal stability, with starting decomposition temperatures above 400 ◦C. Finally,Jiangetal. [48]
(chloroformylphenoxy)phenyl]xanthene, from which the authors obtained aromatic polyamides with
synthetized 9,9-bis[4-(chloroformylphenoxy)phenyl]xanthene, from which the authors obtained
ether and bulky xanthenes groups, by means of low temperature polycondensation with several
aromatic polyamides with ether and bulky xanthenes groups, by means of low temperature
aromatic diamines. Concerning thermal properties, the Tgs varied between 236 to 298 °C, with
pdoelycocomnpdoesnitsiaotnio tnemwpiethrastuevreesr aalt a1r0o%m mataiscsd loiasms binetews.eeCno 4n9c0e rannidn g53t5h e°Crm ina lNp2r, oapnedr tuieps t,ot h5e15T °gCs ivna Orie2.d
Polymers2017,9,414 10of44
between236to298◦C,withdecompositiontemperaturesat10%masslossbetween490and535◦Cin
NP2o,lyamnerds 2u0p17t, o9, 541145 ◦CinO2. 10 of 42
Polymers 2017, 9, 414 10 of 42

SScchheemmee 77.. FFlluuoorriinnaatteedd aarraammiiddss..
Scheme 7. Fluorinated aramids.
Another investigation line is focused in the use of substituted benzophenone in the main chain
AAnnootthheerr iinnvveessttiiggaattiioonn lliinnee iiss ffooccuusseedd iinn tthhee uussee ooff ssuubbssttiittuutteedd bbeennzzoopphheennoonnee iinn tthhee mmaaiinn cchhaaiinn
of aramids. As noted previously, Damaceanu et al. [29] prepared and characterized several aromatic
ooff aarraammiiddss.. AAss nnootteedd pprreevviioouussllyy,, DDaammaacceeaannuu eett aall.. [[2299]] pprreeppaarreedd aanndd cchhaarraacctteerriizzeedd sseevveerraall aarroommaattiicc
polyamides containing pendant phenoxy motifs in benzophenone sub-structure in the structural unit,
ppoollyyaammiiddeess ccoonnttaaiinniinngg ppeennddaanntt pphheennooxxyy mmoottiiffss iinn bbeennzzoopphheennoonnee ssuubb--ssttrruuccttuurree iinn tthhee ssttrruuccttuurraall uunniitt,,
wwwiittihhth tt hhtheeerrmrmmaaall lss tstaatabbbiilliiiltitytyy uu uppp t totoo 3 33888555 ◦ °°CCC aaannnddd TTTgggsss rrraaannngggiiinnnggg fffrrrooommm 222222555 tttooo 222555666 °°◦CCC (((SSSccchhheeemmmeee 888, ,,P PP222333)).) ..

Scheme 8. Aramids with substituted benzophenone in the main chain.
SScchheemmee 88.. AArraammiiddss wwiitthh ssuubbssttiittuutteedd bbeennzzoopphheennoonnee iinn tthhee mmaaiinn cchhaaiinn..
Patil et al. [49] prepared polymers reacting the monomer having aromatic–aliphatic amide and
ethePr altiinlk eatg aels. ,[ 4b9is]- [p(r4e-apmariendo bpeonlzyyml)e-r4s- breenazctaimngid teh]e e mthoenr,o wmiethr hdaifvfienrgen atr momolaet ipc–roaplioprhtaiotincs aomf iIdPeC a onrd
Patiletal.[49]preparedpolymersreactingthemonomerhavingaromatic–aliphaticamideand
eTthPeCr .l Dinikffaegreesn,t ibails -s[c(a4n-anminign ocableonrzimyle)-tr4y-b (eDnSzCam) aindael]y estihs eorf, twheitshe dpoiflfyearemnitd meso slhe opwroedp oTrgtsio inns t hoef IrPanCg oe r
etherlinkages,bis-[(4-aminobenzyl)-4-benzamide]ether,withdifferentmoleproportionsofIPCor
ToPfC 1.9 D7 itfof e2r0e4n °tiCa,l asncadn tnhienyg s chaolworeimd netor ym (aDssS Clo)s sa nbaellyoswis 3 o3f6 t°hCe swe hpeonl yaanmaliydzeesd s bhyo wtheedrm Togsg irna vtihme ertarny.g e
TPC.Differentialscanningcalorimetry(DSC)analysisofthesepolyamidesshowedT sintherangeof
g
of 197S thoa 2b0b4ir ° Cet, aanl.d [ t5h0e] yd sehsocrwibeed tnhoe mpaoslys cloonssd benelsoawtio 3n3 6o f° C4 -whyhdenro axnya-2ly,6z-eddia bmyi nthoeprymriomgirdaivniem wetirtyh.
197to204◦C,andtheyshowednomasslossbelow336◦Cwhenanalyzedbythermogravimetry.
diffeSrheanbt bdiria ceitd a cl.h l[o5r0i]d edse, stcor iboeb tathine speomlyiacroonmdaetnisca htiyopne robfr a4n-hchyeddro axnyd-2 ,c6a-rdbioaxmyilnico pacyirdim teidrminien awteidth
Shabbir et al. [50] describe the polycondensation of 4-hydroxy-2,6-diaminopyrimidine with
daifrfoemreantti cd piaoclyida mchidloe-reidsteesr,s .t oT hoeb toabinta isneemdi aarmoomrpathico uhsy ppoelrybmraenrcsh headd aηnindh rcaanrgbionxgy lbice twaceiden t e0r.2m1 indaLt/egd
different diacid chlorides, to obtain semiaromatic hyperbranched and carboxylic acid terminated
aaarroonmmd aa0tt.ii2cc8 p pdooLllyy/gaa mmaniidddee h--eeassdttee errxss..c eTTlhhleeen oto bbthttaaeiirnnmeedadl aasmmtaoborirplpithhyoo uwussit phpo o1lly0ym%m eemrrssa hshsaa dldo ηsηsi nah trr ataennmggipinneggr abbteuettrwwesee eefnrno 0m0..22 1314 dd6L Lt/o/gg
a5n0d8 0°.C28. AdsL /sge eann dp rheavdio uexsclye,l lSeandt atvhaerrtme aelt satla. b[i2li8t]y awlsiot ha n1a0l%yz mesa tshse l opsoisnl hyacto tnedmepnesraatitounre os ff rao dmia 3m4i6n eto
and 0.28 dL/g and had excellent thermal stability with 10% mass loss at temperatures from
5(0p8e n°Cta. dAecsy slebeenn zperneev-1io,3u-sdliya,m Siandea) vwairtthe deitf faelr.e [n2t8 c]o amlsmo earnciaally azreosm thaeti cp doilaycciodns dtoe nosbattaiionn a oraf ma iddsia wmiitnhe
346 to 508 ◦C. As seen previously, Sadavarte et al. [28] also analyzes the polycondensation of
(ppeenntdaadnetc pylebnetnadzeencyel- 1c,h3a-dinias.m Tihneer)m wailt hp rdoipffeerrteienst creopmomrteedrc iinalc laurdoem 1a0t%ic dmiaacsisd lso stos voabltuaeins aurpa mtoi d46s0 w °iCth
a diamine (pentadecylbenzene-1,3-diamine) with different commercial aromatic diacids to obtain
p(einn dNa2n),t hpiegnht afodre acyral mchidaisn cso. nTthaienrimnga la plirpohpaetricti echs arienpso, ratnedd Tingsc lvuadleu e1s0 v%a rmyiansgs bloestsw veaelnu 1e6s 9u tpo t2o1 54 6°0C .° C
aramidswithpendantpentadecylchains. Thermalpropertiesreportedinclude10%masslossvalues
u(ipn tNo24M),6 h0ali◦lgaChk p(fioonru Nar rea)t,m haiildg. sh[ 5cf1oo]nr etamarianpmilnoigyd esadlci opan hctaahtiiinrcai ncl hgdaaiialnicpsi,dh a,a nt(i2dcS cT)h-g5sa- i[vn4as-l(,u4a-enmsd evTtahryysliv-n2ag-lp ubheetsthwvaaleiremyniin d1gy69lbp eteotnw 2tea1en5no °y1Cl6-.9
aminMoa)blleankzpooyulra me2ti naol.] i[s5o1p]h etmhaplilco yaecdid ,a inch air aplo dlyicaocindd, e(n2sSa)t-i5o-n[4 p-(r4o-mceessthg wyli-t2h- pahlitphhaalitmic iadnydlp aernotmanaotyicl -
to215◦C.
admiiisnooc)ybaennaztoeys.l aTmhien op]oisloyapmhtihdaelsi co abctiadin, eind ap rpeoselyncteodn dienntesraetsiotinn gp rtohceersms awl ipthro paleirpthieast i(c5 %an dm aarsos mloastsic
Mallakpouretal.[51]employedachiraldiacid, (2S)-5-[4-(4-methyl-2-phthalimidylpentanoyl-
dtieismopcyearantautrees .u pT htoe 3p5o5l y°Cam inid Ne2s) . obtained presented interesting thermal properties (5% mass loss
amino)benzoylamino]isophthalic acid, in a polycondensation process with aliphatic and aromatic
Flame-retardancy polyamides were also analyzed by several authors. Also, the group of
temperature up to 355 °C in N2).
diisocyanates. The polyamides obtained presented interesting thermal properties (5% mass loss
Mallakpour et al. [52] describe the synthesis of aromatic polyamides with flame retardancy
Flame-retardancy polyamides were also analyzed by several authors. Also, the group of
tepmroppeerrattiuesr,e uupsintog 3c5o5n◦vCenintioNn2a)l. heating as well as microwave irradiation. The polymers were
Mallakpour et al. [52] describe the synthesis of aromatic polyamides with flame retardancy
pproreppearrtieeds ,u suisnign ga dcioancivde nmtoionnoaml ehr ewatiitnhg a La-sp hwenelyl laalsa nminiectreotrwaabvroem iorrpahdtihaatiloimn.i dTe hger opuopl.y mers were
To improve thermal resistance and flame retardancy properties, halogens as bromine and
prepared using a diacid monomer with a L-phenylalaninetetrabromophthalimide group.
chlorine are usually employed in the formulation of all kind of polymers, also in aromatic
To improve thermal resistance and flame retardancy properties, halogens as bromine and
polyamides. For example, Rafiee et al. [53] describe the preparation of flame-retardancy polyamides,
chlorine are usually employed in the formulation of all kind of polymers, also in aromatic
p olyamides. For example, Rafiee et al. [53] describe the preparation of flame-retardancy polyamides,