Inkqubela phambili yoPhando kwi-Non-Isocyanate Polyurethanes
Ukusukela ekuqalisweni kwabo ngo-1937, izixhobo ze-polyurethane (PU) zifumene izicelo ezibanzi kumacandelo ahlukeneyo abandakanya ezothutho, ukwakhiwa, iikhemikhali zepetroli, amalaphu, ubunjineli bomatshini kunye nombane, i-aerospace, ukhathalelo lwezempilo kunye nezolimo. Ezi zixhobo zisetyenziswa kwiifom ezifana neeplastiki zogwebu, iifayibha, ii-elastomers, ii-agent zokungangeni manzi, ii-synthetic leathers, i-coatings, i-adhesives, i-paving materials kunye nezixhobo zonyango. I-PU yesiNtu idityaniswe ikakhulu ukusuka kwi-isocyanates ezimbini okanye ngaphezulu kunye ne-macromolecular polyols kunye nezandiso ezincinci zemolekyuli. Nangona kunjalo, ubuthi bendalo be-isocyanates bubeka umngcipheko omkhulu kwimpilo yabantu kunye nokusingqongileyo; ngaphezu koko ngokuqhelekileyo zithathwe kwi-phosgene-i-precursor enetyhefu kakhulu-kunye nezixhobo ze-amine ezihambelanayo.
Ngokubhekiselele kwishishini lemichiza langoku lokufuna uphuhliso oluluhlaza kunye noluzinzileyo, abaphandi baye bagxila ngakumbi ekutshintsheni i-isocyanates ngemithombo ehambelana nokusingqongileyo ngelixa behlola iindlela zenoveli ze-non-isocyanate polyurethanes (NIPU). Eli phepha lazisa iindlela zokulungiselela i-NIPU ngelixa liphonononga ukuqhubela phambili kwiindidi ezahlukeneyo ze-NIPU kunye nokuxoxa ngamathemba abo exesha elizayo ukubonelela ngereferensi yophando olongezelelweyo.
I-1 Synthesis ye-Non-Isocyanate Polyurethanes
I-synthesis yokuqala ye-low molecular weight carbamate compounds usebenzisa i-monocyclic carbonates edityaniswe ne-aliphatic diamines yenzeke ngaphandle kwe-1950s-iphawula umzuzu obalulekileyo malunga ne-non-isocyanate polyurethane synthesis. Okwangoku kukho iindlela ezimbini eziphambili zokuvelisa i-NIPU: Eyokuqala ibandakanya ukusabela okongeziweyo okuhamba ngamanyathelo phakathi kwebinary cyclic carbonates kunye nebinary amines; eyesibini ibandakanya iimpendulo zepolycondensation ezibandakanya idiurethane intermediates ecaleni kwediols eziququzelela utshintshiselwano lwesakhiwo ngaphakathi kwecarbamates. I-diamarboxylate intermediates inokufumaneka ngeendlela ze-cyclic carbonate okanye ze-dimethyl carbonate (DMC); ngokusisiseko zonke iindlela zisabela ngamaqela e-carbonic acid avelisa ukusebenza kwe-carbamate.
La macandelo alandelayo achaza iindlela ezintathu ezahlukeneyo zokudibanisa i-polyurethane ngaphandle kokusebenzisa isocyanate.
1.1Indlela ye-Binary Cyclic Carbonate
I-NIPU inokwenziwa ngokongezwa ngokwenyathelo elibandakanya ibhinary cyclic carbonate edityaniswa nebinary amine njengoko kubonisiwe kuMfanekiso 1.
Ngenxa yamaqela amaninzi e-hydroxyl akhoyo ngaphakathi kweeyunithi eziphindaphindayo kunye nesakhiwo sayo esiphambili le ndlela ivelisa oko kubizwa ngokuba yi-polyβ-hydroxyl polyurethane (PHU). I-Leitsch et al., iphuhlise uthotho lwee-PHUs ze-polyether ezisebenzisa ii-polyethers ze-cyclic carbonate-terinated ecaleni kwebinary amines kunye ne-molecule ezincinci ezithathwe kwibinary cyclic carbonates-ithelekisa ezi ngokuchasene neendlela zemveli ezisetyenziselwa ukulungisa ii-polyether PUs. Iziphumo zabo zibonise ukuba amaqela e-hydroxyl ngaphakathi kwe-PHUs enza lula iibhondi ze-hydrogen kunye ne-nitrogen / i-athomu yeoksijini ebekwe ngaphakathi kwamacandelo athambileyo / anzima; ukwahluka phakathi kwamacandelo athambileyo kukwaphembelela indlela yokuziphatha kwe-hydrogen bonding kunye ne-microphase yokwahlula idigri ezithi emva koko zichaphazele iimpawu zokusebenza ngokubanzi.
Ngokuqhelekileyo iqhutywe ngaphantsi kwamaqondo obushushu angaphezu kwe-100 °C le ndlela ivelisa akukho mveliso ngexesha leenkqubo zokuphendula iyenza ingabi naluvelwano malunga nokufuma ngelixa ivelisa iimveliso ezizinzileyo ezingenakukhathazeka okongeziweyo kodwa zidinga izinyibilikisi zendalo ezibonakaliswe yi-polarity eqinile njenge-dimethyl sulfoxide (DMSO), N, N-dimethylformamide yandisa amaxesha amaninzi usuku olunye njalo njalo. Zinike ubunzima obuphantsi bemolekyuli rhoqo sisiwa mfutshane ngaphantsi kwe-30k g/mol inika umngeni wemveliso enkulu ngenxa yokuba ubukhulu becala ibalelwa kwiindleko eziphezulu ezinxulumene noko kunye nokungonelanga kwamandla abonakaliswe yi-PHUs ngaphandle kwezicelo ezithembisayo ezithatha imimandla yemathiriyeli ebumba inkumbulo yakha imixube yokuncamathelisa njl njl.
1.2Indlela yeMonocylic Carbonate
I-Monocylic carbonate iphendula ngokuthe ngqo ne-diamine ebangela ukuba i-dicarbamate inamaqela okugqibela e-hydroxyl ethi emva koko iqhube unxibelelwano olukhethekileyo lwe-transesterification/polycondensation ecaleni kwe-diols ekugqibeleni ivelise i-NIPU ngokwesakhiwo efana nabalingane bemveli ababoniswe ngokubonakalayo kwiSazobe sesi-2.
Iintlobo ezahlukeneyo ze-monocylic eziqhelekileyo ezisetyenziswayo ziquka i-ethylene kunye ne-propylene carbonated substrates apho iqela lika-Zhao Jingbo kwiYunivesithi yaseBeijing ye-Chemical Technology libandakanye iidiamine ezahlukeneyo ezisabela kuzo ngokuchasene namaqumrhu ashicileleyo ekuqaleni afumana amacandelo ahlukeneyo e-dicarbamate intermediaries ngaphambi kokuba aqhubele phambili kwizigaba ze-condensation usebenzisa i-polyculitis okanye i-polyminediol Ukwenziwa kwemigca yemveliso eyahlukeneyo ebonisa iimpawu ezichukumisayo ezishushu/zoomatshini ezifikelela kwiindawo ezinyukayo zokunyibilika zijikeleza kuluhlu olwaba malunga ne-125 ~ 161°C amandla okuzibamba afikelela incopho kufutshane ne-24MPa amazinga obude asondele kwi-1476%. Wang et al., indibaniselwano efanayo enempembelelo equka iDMC edityaniswe ngokulandelelanayo w/hexamethylenediamine/cyclocarbonated precursors synthesizing hydroxy-terinated derivatives later subjected biobased dibasic acids like oxalic/sebacic/acids adipic-acid-terephtalics okuphumelela 3 iziphumo zokugqibela Amandla e-tensile aguquguquka9 ~ 17 Ubude beMPa bohluka35% ~ 235%.
Ii-ester ze-Cyclocarbonic zisebenzisana ngokufanelekileyo ngaphandle kokufuna ii-catalysts phantsi kweemeko eziqhelekileyo ezigcina ubude bobushushu obumalunga nama-80° ukuya kwi-120°C emva kokuguqulelwa kwe-transesterification ngokuqhelekileyo zisebenzisa iisistim ze-catalytic ezisekwe kwi-organotin eziqinisekisa ukusetyenzwa kweyona ndlela ilungileyo ayigqithi kuma-200°. Ngaphaya kweenzame zokuxinanisa ezijolise kwigalelo le-diolic elikwaziyo ukuzenzela i-polymerization/deglycolysis phenomena eququzelela isizukulwana seziphumo ezinqwenelekayo inika indlela yokusebenza eco-friendly kakhulu ivelisa intsalela yemethanol/imolekyuli encinci-diolilic ngoko ke inika iindlela ezinokusetyenziswa eziya phambili.
1.3Indlela yeDimethyl Carbonate
I-DMC imele i-ecologically sound/non-toxic alternative equka izinto ezininzi ezisebenzayo ezibandakanya imethyl/methoxy/carbonyl configurations ephucula iprofayili yereactivity evumela ngokubonakalayo iindibano zokuqala apho iDMC inxibelelana ngokuthe ngqo w/diamines zenza abalamli abancinci be-methyl-carbamate banqunyanyiswa kulandele emva koko ukunyibilika kwezenzo zokunyibilika. ikhonkco elincinci-i-extender-diolics/i-polyol enkulu ekhokelela ekuveleni okufunwayo emva kwezakhiwo zepolymer ezibonisiweyo ngokufanelekileyo ngeFigure3.
I-Deepa et.al yenziwe imali enkulu kumandla asele ekhankanyiwe ngasentla asebenzisa i-sodium methoxide catalysis eququzelela ulwakhiwo oluphakathi olwahlukeneyo emva koko lubandakanya izandiso ezijoliswe kuluhlu olufikelela kuvuthondaba olulinganayo lwecandelo elinzima lokuqamba ukufikelela kubunzima beemolekyuli malunga (3 ~20) x10^3g/spamol iglasi yotshintsho-0 ° C1 iglasi yokutshintsha-2 ° C. I-Pan Dongdong ikhethe ukudityaniswa kobuchule okubandakanya i-DMC i-hexamethylene-diaminopolycarbonate-polyalcohols eqonda iziphumo eziphawulekayo ezibonisa i-tensile-strengt metrics oscillating10-15MPa umlinganiselo wobude obusondela kwi-1000% -1400%. Izinto eziphandayo ezijikeleze iimpembelelo ezahlukeneyo zokwandisa ityathanga zibonakalise ukhetho olulungele ukulungelelanisa i-butanediol/i-hexanediol xa inani leatom-inombolo ligcina ulungelelwano lukhuthaza ukuphuculwa kwekristale okuyalelweyo okubonwa kuwo wonke amatyathanga. at230℃ .Uphononongo olongezelelweyo olujolise ekufumaneni i-non-isocyante-polyureas leveraging diazomonomer uthethathethwano olulindelekileyo usetyenziso lwepeyinti olunokubakho oluvelayo oluluncedo oluthelekisekayo ngaphezu kwezixhobo ze-vinyl-carbonaceous eziqaqambisa ukusebenza kweendleko/iindlela ezibanzi zokukhangela ezikhoyo.Kufuneka inkuthalo efunekayo ngokunxulumene neendlela ezininzi zobuchule obuqhelekileyo. ubushushu obuphezulu/indawo efunxayo ezichasayo iimfuno zokunyibilikisa ngokwenza oko kuncitshiswe imijelo yenkunkuma ethintelwa ubukhulu becala kuphela ukungcola kwemethanol/imolekyuli encinci-diolic eseka iiparadigms eziluhlaza zizonke.
2 Izahlulo ezithambileyo ezahlukeneyo ze-non-isocyanate polyurethane
2.1 Polyether polyurethane
I-Polyether polyurethane (PEU) isetyenziswa ngokubanzi ngenxa yamandla ayo aphantsi okudityaniswa kweebhondi ze-ether kwicandelo elithambileyo lokuphinda iiyunithi, ukujikeleza okulula, ukuguquguquka okubalaseleyo kobushushu obuphantsi kunye nokumelana ne-hydrolysis.
Kebir et al. i-polyether polyurethane eyenziwe nge-DMC, i-polyethylene glycol kunye ne-butanediol njengezinto eziluhlaza, kodwa ubunzima be-molecular yayiphantsi (7 500 ~ 14 800g / mol), i-Tg yayingaphantsi kwe-0℃, kunye nendawo yokunyibilika nayo yayiphantsi (38 ~ 48 ℃), kwaye amandla kunye nezinye iimpawu zokusetyenziswa kwakunzima ukuhlangabezana neemfuno. Iqela lophando likaZhao Jingbo lasebenzisa i-ethylene carbonate, i-1, i-6-hexanediamine kunye ne-polyethylene glycol ukuze idibanise i-PEU, enobunzima be-molecular 31 000g / mol, amandla obunzima be-5 ~ 24MPa, kunye nobude bekhefu kwi-0.9% ~ 1 388%. Ubunzima bemolekyuli yoluhlu oluhlanganisiweyo lwe-polyurethanes enuka kamnandi yi-17 300 ~ 21 000g/mol, i-Tg yi-19 ~ 10 ℃, indawo yokunyibilika yi-102 ~ 110℃, amandla okuqina yi-12 ~ 38MPa, kunye nereyithi ye-elastic yokubuyisela i-9% 20% ubude be-9% 20% ende.
Iqela lophando likaZheng Liuchun kunye noLi Chuncheng balungiselela i-1 ephakathi, i-6-hexamethylenediamine (BHC) kunye ne-dimethyl carbonate kunye ne-1, i-6-hexamethylenediamine, kunye ne-polycondensation kunye ne-polycondensation eneemolekyuli ezincinci ze-straight chain diols kunye ne-polytetrahydrofuranediols (Mn = 2 000). Uchungechunge lwe-polyether polyurethanes (NIPEU) kunye nomzila we-non-isocyanate zalungiswa, kwaye ingxaki yokudibanisa i-intermediates ngexesha lokuphendula yasonjululwa. Ubume kunye neepropati ze-polyether polyurethane yendabuko (HDIPU) elungiselelwe yi-NIPEU kunye ne-1, i-6-hexamethylene diisocyanate yafaniswa, njengoko kuboniswe kwiThebhile 1.
| Isampulu | Icandelo elinzima iqhezu lobunzima/% | Ubunzima bemolekyuli/(g·mol^(-1)) | Isalathisi sokusabalalisa ubunzima bemolekyuli | Amandla okuqina/MPa | Ukwandiswa ngexesha lekhefu/% |
| NIPEU30 | 30 | 74000 | 1.9 | 12.5 | 1250 |
| NIPEU40 | 40 | 66000 | 2.2 | 8.0 | 550 |
| HDIPU30 | 30 | 46000 | 1.9 | 31.3 | 1440 |
| HDIPU40 | 40 | 54000 | 2.0 | 25.8 | 1360 |
Uluhlu loku-1
Iziphumo kwiThebhile 1 zibonisa ukuba ukungafani kwesakhiwo phakathi kwe-NIPEU kunye ne-HDIPU ikakhulu ngenxa yecandelo elinzima. Iqela urea eveliswe yi reaction yecala le-NIPEU ifakwe ngokungenamkhethe kwicandelo elinzima le-molecular chain, liqhekeza icandelo elinzima ukwenza iibhondi ze-hydrogen eziyalelweyo, okukhokelela kwiibhondi ze-hydrogen ezibuthathaka phakathi kwamatyathanga e-molecular yecandelo elinzima kunye ne-crystallinity ephantsi yecandelo elinzima, okubangela ukuhlukana kwesigaba esiphantsi se-NIPEU. Ngenxa yoko, iipropathi zayo zemishini zibi kakhulu kune-HDIPU.
2.2 Polyester Polyurethane
I-Polyester polyurethane (PETU) ene-polyester diols njengamacandelo athambileyo ane-biodegradability elungileyo, i-biocompatibility kunye ne-mechanical properties, kwaye ingasetyenziselwa ukulungiselela i-scaffolds yobunjineli beethishu, eyimathiriyeli ye-biomedical enethemba elikhulu lokusebenzisa. Iipolyester diols eziqhele ukusetyenziswa kumacandelo athambileyo yi-polybutylene adipate diol, i-polyglycol adipate diol kunye ne-polycaprolactone diol.
Ngaphambili, uRokicki et al. iphendule i-ethylene carbonate kunye ne-diamine kunye ne-diols ezahlukeneyo (i-1, i-6-hexanediol, i-1, i-10-n-dodecanol) ukufumana i-NIPU eyahlukileyo, kodwa i-NIPU edibeneyo yayinobunzima obuphantsi be-molecular kunye ne-Tg ephantsi. UFarhadian et al. ilungiswe i-polycyclic carbonate isebenzisa i-oyile yembewu kajongilanga njengemathiriyeli ekrwada, emva koko ixutywe ne-bio-based polyamines, igqunywe epleyitini, kwaye yanyangwa nge-90 ℃ ngeyure ezingama-24 ukufumana ifilimu ye-thermosetting polyester polyurethane, ebonisa ukuzinza okuhle kwe-thermal. Iqela lophando likaZhang Liqun osuka kwiYunivesithi yaseChina yeTekhnoloji yaseSouth China lenze uthotho lweediamines kunye necyclic carbonates, kwaye emva koko zajikwa nge-biobased dibasic acid ukufumana i-biobased polyester polyurethane. Iqela lophando Zhu Jin kwi Ningbo Institute of Materials Research, Chinese Academy of Sciences walungisa diaminodiol hard segment usebenzisa hexadiamine kunye vinyl carbonate, kwaye emva koko polycondensation kunye bio-based unsaturated dibasic acid ukufumana uthotho polyester polyurethane, enokusetyenziswa njengepeyinti emva kokunyanga ultraviolet [23]. Iqela lophando likaZheng Liuchun kunye noLi Chuncheng basebenzisa i-adipic acid kunye ne-aliphatic diols ezine (i-butanediol, i-hexadiol, i-octanediol kunye ne-decanediol) ngamanani ahlukeneyo e-carbon athomu ukulungiselela i-polyester diols ehambelanayo njengamacandelo athambileyo; Iqela le-non-isocyanate polyester polyurethane (PETU), elibizwa ngokuba yinani le-athomu ye-carbon ye-aliphatic diols, yafunyanwa ngokunyibilika kwe-polycondensation kunye ne-hydroxy-sealed hard segment prepolymer elungiselelwe yi-BHC kunye ne-diols. Iimpawu zomatshini zePETU zibonisiwe kwiTheyibhile yesi-2.
| Isampulu | Amandla okuqina/MPa | Imodyuli ye-elastic/MPa | Ukwandiswa ngexesha lekhefu/% |
| PETU4 | 6.9±1.0 | 36±8 | 673±35 |
| PETU6 | 10.1±1.0 | 55±4 | 568±32 |
| PETU8 | 9.0±0.8 | 47±4 | 551±25 |
| PETU10 | 8.8±0.1 | 52±5 | 137±23 |
Itheyibhile 2
Iziphumo zibonisa ukuba icandelo elithambileyo le-PETU4 linobuninzi be-carbonyl ephezulu, i-hydrogen bond eyomeleleyo kunye necandelo elinzima, kunye nenqanaba elisezantsi lokuhlukana. Icrystallization yawo omabini amacandelo athambileyo kunye anzima anqunyelwe, abonisa indawo yokunyibilika ephantsi kunye namandla okuqina, kodwa olona bude buphezulu ngexesha lekhefu.
2.3 I-Polycarbonate polyurethane
I-Polycarbonate polyurethane (PCU), ingakumbi i-PCU ye-aliphatic, inokumelana ne-hydrolysis ebalaseleyo, ukuxhathisa i-oxidation, uzinzo olulungileyo lwebhayoloji kunye nokuhambelana kwezinto eziphilayo, kwaye inethemba elihle lokusetyenziswa kwintsimi ye-biomedicine. Okwangoku, uninzi lwe-NIPU elungisiweyo isebenzisa i-polyether polyols kunye ne-polyester polyols njengamacandelo athambileyo, kwaye kukho iingxelo ezimbalwa zophando kwi-polycarbonate polyurethane.
I-non-isocyanate polycarbonate polyurethane elungiselelwe liqela lophando likaTian Hengshui kwiYunivesithi yaseSouth China yeTekhnoloji inobunzima bemolekyuli obungaphezulu kwe-50 000 g / mol. Impembelelo yeemeko zokusabela kwi-molecular weight ye-polymer ifundwe, kodwa iimpawu zayo zomatshini azizange zichazwe. Iqela lophando likaZheng Liuchun kunye noLi Chuncheng balungiselela i-PCU isebenzisa i-DMC, i-hexanediamine, i-hexadiol kunye ne-polycarbonate diols, kwaye yathiywa ngokuba yi-PCU ngokwenxalenye yobunzima beyunithi ephindaphindayo yecandelo elinzima. Iimpawu zoomatshini zibonisiwe kwiThebhile yesi-3.
| Isampulu | Amandla okuqina/MPa | Imodyuli ye-elastic/MPa | Ukwandiswa ngexesha lekhefu/% |
| PCU18 | 17±1 | 36±8 | 665±24 |
| PCU33 | 19±1 | 107±9 | 656±33 |
| PCU46 | 21±1 | 150±16 | 407±23 |
| PCU57 | 22±2 | 210±17 | 262±27 |
| PCU67 | 27±2 | 400±13 | 63±5 |
| PCU82 | 29±1 | 518±34 | 26±5 |
Itheyibhile 3
Iziphumo zibonisa ukuba i-PCU inobunzima obuphezulu be-molecular, ukuya kuthi ga kwi-6 × 104 ~ 9 × 104g/mol, indawo yokunyibilika ukuya kuthi ga kwi-137 ℃, kunye namandla okuqina ukuya kuthi ga kwi-29 MPa. Olu hlobo lwe-PCU lunokusetyenziswa mhlawumbi njengeplastiki eqinile okanye njenge-elastomer, enethuba elihle lokufaka isicelo kwintsimi ye-biomedical (njenge-scaffolds yobunjineli bomntu okanye izixhobo ze-cardiovascular implant).
2.4 I-Hybrid non-isocyanate polyurethane
I-Hybrid non-isocyanate polyurethane (i-hybrid NIPU) kukuqaliswa kwe-epoxy resin, i-acrylate, i-silica okanye amaqela e-siloxane kwisakhelo se-molecular polyurethane ukwenza i-network interpenetrating, ukuphucula ukusebenza kwe-polyurethane okanye ukunika i-polyurethane imisebenzi eyahlukeneyo.
Feng Yuelan et al. yasabela bio-based epoxy ioyile yesoya kunye CO2 ukudibanisa pentamonic cyclic carbonate (CSBO), kwaye yazisa bisphenol A diglycidyl ether (epoxy resin E51) kunye namacandelo chain engqongqo ngakumbi ukuphucula NIPU eyenziwe CSBO yaqina ngeamine. Ikhonkco yemolekyuli iqulethe icandelo elide eliguquguqukayo le-oleic acid / linoleic acid. Ikwanayo namacandelo ekhonkco aqinileyo, ukuze abe namandla omatshini aphezulu kunye nokuqina okuphezulu. Abanye abaphandi baye badibanisa iintlobo ezintathu ze-NIPU prepolymers kunye namaqela okuphela kwe-furan ngokusebenzisa isantya sokuphendula i-diethylene glycol bicyclic carbonate kunye ne-diamine, emva koko basabela nge-polyester engaxutywanga ukuze balungiselele i-polyurethane ethambileyo kunye nomsebenzi wokuziphilisa, kwaye baqonda ngempumelelo ukusebenza kakuhle kokuziphilisa kwe-NIPU ethambileyo. I-Hybrid NIPU ayinayo kuphela iimpawu ze-NIPU ngokubanzi, kodwa inokuba ne-adhesion engcono, i-asidi kunye ne-alkali ukumelana nokugqwala, ukuxhathisa kwe-solvent kunye namandla omatshini.
3 Ukujonga
I-NIPU ilungiselelwe ngaphandle kokusetyenziswa kwe-isocyanate enetyhefu, kwaye ngoku ifundwa ngendlela ye-foam, i-coating, i-adhesive, i-elastomer kunye nezinye iimveliso, kwaye inoluhlu olubanzi lwamathemba okusebenza. Nangona kunjalo, uninzi lwazo lusakhawulelwe kuphando lwebhubhoratri, kwaye akukho mveliso inkulu. Ukongezelela, ngokuphuculwa kwemigangatho yokuphila kwabantu kunye nokukhula okuqhubekayo kwemfuno, i-NIPU enomsebenzi omnye okanye imisebenzi emininzi iye yaba yikhokelo yophando ebalulekileyo, njenge-antibacterial, self-repair, memory memory, i-flame retardant, ukumelana nokushisa okuphezulu kunye nokunye. Ngoko ke, uphando lwexesha elizayo kufuneka luqonde indlela yokuqhawula kwiingxaki eziphambili ze-industrialization kunye nokuqhubeka nokuphonononga isikhokelo sokulungiselela i-NIPU esebenzayo.
Ixesha lokuposa: Aug-29-2024