Horumarka Cilmi-baarista ee Polyurethane aan Isocyanate ahayn
Tan iyo markii la bilaabay 1937, polyurethane (PU) agabku waxay heleen codsiyo badan oo dhinacyo kala duwan ah oo ay ku jiraan gaadiidka, dhismaha, kiimikooyinka batroolka, dharka, farsamada iyo injineernimada korantada, hawada hawada, daryeelka caafimaadka, iyo beeraha. Agabkaan waxaa loo isticmaalaa qaabab ay ka mid yihiin balaastikada xumbo, fiilooyinka, balaastikada, walxaha biyaha celinaya, haragga synthetic, dahaarka, xabagta, alaabta laamiyada iyo sahayda caafimaadka. PU-dhaqameedka ayaa ugu horrayn laga soo saaray laba ama in ka badan oo isocyyanates ah oo ay la socdaan polyols makromolecular iyo fidiyeyaasha silsiladaha kelliyada yar yar. Si kastaba ha noqotee, sunta dabiiciga ah ee isocyanates waxay halis weyn u tahay caafimaadka aadanaha iyo deegaanka; Intaa waxaa dheer waxay caadi ahaan ka soo jeedaan fosgene-oo ah horudhac aad u sun ah-iyo alaabta ceeriin ee aminiga ah.
Marka la eego raadinta warshadaha kiimikada casriga ah ee ku dhaqanka cagaarka iyo horumarka waara, cilmi-baarayaashu waxay si sii kordheysa diiradda u saarayaan beddelka isocyanates ee kheyraadka deegaanka u saaxiibka ah iyadoo sahaminta dariiqyada isku-dhafka cusub ee polyurethanes-ka aan isocyanate (NIPU). Warqadani waxay soo bandhigaysaa dariiqooyinka u diyaargarowga NIPU iyadoo dib u eegis lagu sameynayo horumarka noocyada kala duwan ee NIPU-yada lagana hadlayo rajada mustaqbalka si ay u bixiyaan tixraac cilmi baaris dheeraad ah.
1 Qalabaynta Polyurethane aan Isocyanate ahayn
Isku-dubaridkii ugu horreeyay ee xeryahooda carbmate ee culeyska hooseeya iyadoo la adeegsanayo karbonada monocyclic oo ay weheliso diamines aliphatic ayaa ka dhacay dibedda 1950-meeyadii - taasoo calaamad u ah daqiiqad muhiim ah oo ku wajahan isku-dhafka polyurethane ee aan isocyanate. Hadda waxa jira laba hab oo asaasi ah oo lagu soo saaro NIPU: Midda kowaad waxay ku lug leedahay falcelinta isugeynta ee u dhexeeya karbonnada wareegga ah ee binary iyo amines binary; Midda labaad waxa ay keenaysaa falcelinta kondensation-ka ee ku lug leh dhexdhexaadiyeyaasha diurethane oo ay weheliyaan diols-ka fududeeya is-weydaarsiga qaab-dhismeedka carrabamates. Dhexdhexaadiyeyaasha Diamarboxylate waxaa laga heli karaa mid ka mid ah waddooyinka carbonate cyclic ama dimethyl carbonate (DMC); Asal ahaan hababka oo dhan waxay uga falceliyaan kooxaha kaarbooniga ah ee ka soo baxa carbamate functionalities.
Qaybaha soo socdaa waxay sharraxayaan saddex hab oo kala duwan oo lagu soo saaro polyurethane iyada oo aan la isticmaalin isocyanate.
1.1 Waddada meertada meertada ah
NIPU waxaa lagu soo saari karaa iyada oo loo marayo isugeyn si tartiib tartiib ah oo ku lug leh kaarboonayt wareegtada binary oo ay weheliso amine binary sida lagu muujiyey sawirka 1.
Sababo la xiriira kooxo badan oo hydroxyl ah oo ku dhex jira unugyo soo noqnoqda oo ay la socdaan qaab dhismeedka silsiladda ugu weyn habkani guud ahaan waxa uu keenaa waxa loo yaqaan polyβ-hydroxyl polyurethane (PHU). Leitsch et al., Waxay soo saareen taxane PHU-yada polyeter-ka ah oo shaqaaleysiiyay polyeter-ka-soo-baxa kaarboonaysiinta oo ay weheliyaan amines binary iyo molecules yaryar oo laga soo qaatay carbonates-cyclic binary-iyado kuwan isbarbar dhigaya hababka dhaqameed ee loo isticmaalo diyaarinta polyether PUs. Natiijooyinkoodu waxay muujiyeen in kooxaha hydroxyl ee ku jira PHU-yada ay si sahal ah u sameeyaan curaarta hydrogen oo leh atamyada nitrogen/oxygen ee ku dhex yaal qaybo jilicsan/ adag; kala duwanaanshaha qaybaha jilicsan ayaa sidoo kale saameeya habdhaqanka isku xidhka hydrogen iyo sidoo kale heerarka kala soocida microphase taas oo markaa saameynaysa sifooyinka waxqabadka guud.
Sida caadiga ah waxaa lagu qabtaa heerkul ka hooseeya 100 °C dariiqan ma soo saaro wax soo saar leh inta lagu jiro hababka falcelinta taasoo ka dhigaysa mid aan dareen lahayn qoyaanka iyada oo la soo saarayo alaabooyin deggan oo aan lahayn walaac isbeddel ah si kastaba ha ahaatee waxay u baahan yihiin dareerayaasha organic ee lagu garto polarity xooggan sida dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) iwm . oo ay weheliso awood aan ku filnayn oo ay soo bandhigtay PHU-yada natiijo ahaan, in kasta oo ay jiraan codsiyo ballaadhinaya oo ku saabsan qaybaha walxaha qoyaanka ah ee qaabeeya xusuusta waxay dhistaa qaab-dhismeed dhejisyo ah oo daahan xalalka xumbo iwm.
1.2 Jidka Carbonate monocylic
Kaarboonka monocylic wuxuu si toos ah ula falgalaa diamine taasoo keentay dicarbamate haysashada kooxaha dhamaadka hydroxyl ka dibna la maro isdhexgalka transesterification/polycondensation gaar ah oo ay weheliso diols aakhirka soo saara NIPU qaab-dhismeed dhaqameed la mid ah oo muuqaal ahaan lagu sawiray sawirka 2.
Kala duwanaanshaha monocylic ee sida caadiga ah loo shaqeeyo waxaa ka mid ah ethylene & propylene carbonated substrates halkaas oo kooxda Zhao Jingbo ee Jaamacadda Beijing ee Tiknoolajiyada Kiimikada ay ku hawlan yihiin diamines kala duwan iyaga oo ka soo horjeeda hay'adaha wareegtada waxay markii hore heleen dhexdhexaadin qaabdhismeedka dicarbamate ee kala duwan ka hor intaanay sii wadin marxaladaha isku-dhafka ah ee isticmaalka polytetetradiol-hydropolye-guul leh. khadadka alaabada kala duwan ee soo bandhigaya guryaha kulaylka/farsamada cajiibka ah oo gaadhay kor u kacaya dhibco dhalaalid ah oo dul wareegaya qiyaas ahaan 125 ~ 161°C awoodaha xajinta ee ugu saraysa 24MPa heerka dhererka dhererka ee ku dhow 1476%. Wang et al., Isku darka la midka ah ee leveraged oo ka kooban DMC oo la isku daray siday u kala horreeyaan w/hexamethylenediamine/cyclocarbonated horudhacyada soosaaraya hydroxy-la joojiyay ka dib waxaa la keenay asiidh dibasic biobased sida oxalic/sebacic/acids adipic-acid-terephtalics gaadhista natiijada kama dambaysta ah ee muujinaysa heerka cabbirka Awoodaha xajinta ee isbedbeddelaya9 ~ 17 MPa elongations kala duwanaansho 35% ~ 235%.
Cyclocarbonic esters waxay si wax ku ool ah u hawlgalaan iyaga oo aan u baahnayn kicinta xaaladaha caadiga ah iyaga oo ilaalinaya dhererka heerkulka qiyaastii 80 ° ilaa 120 ° C transesterifications-ka xiga sida caadiga ah waxay shaqaaleeyaan nidaamyada organotin-ku salaysan ee hubinta habka ugu fiican ee aan dhaafin 200 °. Marka laga reebo dadaallada uumiga oo kaliya ee lagu beegsanayo agabka diolic ee karti u leh is-polymerization/ ifafaale deglycolysis fududeynaya jiilka natiijooyinka la rabo ayaa keenaya habka dabiiciga ah ee saaxiibtinimo-eco-saaxiibtinimo oo inta badan dhalisa hadhaaga methanol/yar-molecule-diolic taasoo soo bandhigaysa beddelka warshadaha ee hore u socda.
1.3 Dimethyl Carbonate Route
DMC waxay matalaysaa deegaan ahaan dhawaaq/bedel aan sun ahayn oo muujinaya unugyo firfircoon oo badan oo ay ku jiraan qaabaynta methyl/methoxy/carbonyl oo kor u qaadaysa muuqaalada falcelinta taas oo DMC ay si toos ah ula falgasho iyo diamines samaynta dhexdhexaadiyayaal yar yar oo methyl-carbamate ah oo la joojiyay ka dib marka lagu daro ficilada dhalaalka Silsilad-yar-yar oo dheeraad ah-diolics/ka kooban-polyol-weyn oo horseeda soo ifbaxa ugu dambaynta ee la raadsado qaab-dhismeedka polymerka oo si waafaqsan sawirka3.
Deepa et.al waxay ka faa'iidaysteen dhaqdhaqaaqyada aan kor ku soo sheegnay oo ka faa'iideysanaya soodhiyam methoxide catalysis abaabulida qaabab kala duwan oo dhexdhexaad ah ka dibna ka qaybqaata kordhinta bartilmaameedka ah ee soo afjaraya taxane u dhigma qaybo adag oo gaadhaya miisaanyo qiyaas ah (3 ~ 20) x10 ^ 3g / molning 0 galaas °C). Pan Dongdong wuxuu doortay lammaane istiraatijiyadeed oo ka kooban DMC hexamethylene-diaminopolycarbonate-polyalcohols isagoo garwaaqsanaya natiijooyin xusid mudan oo muujinaya cabbiraadaha xummaanta-xoogga oscillating10-15MPa saamiga dhererka ee ku soo wajahan 1000%-1400%. Dabagalka baadhista ee ku xeeran saamaynta silsilado-fidinta ee kala duwan ayaa daaha ka qaaday doorbidyada si wanaagsan isu waafajinaya xulashada butanediol/hexanediol marka tirada atomikada ay ilaaliso sinnaanta kor u qaadida kor u qaadida kristalinity ee la amray ee lagu arkay silsiladaha oo dhan. Sahaminta dheeraadka ah ee loogu talagalay soo saarista non-isocyant-polyureas ka-qaybgalka diazomonomer ee la filayo codsiyada rinjiga ee suurtogalka ah ee soo baxaya faa'iidooyinka isbarbardhigga ah ee vinyl-carbonaceous ee muujinaya waxtarka-wax-ku-oolnimada/ballaarinta waddooyinka la heli karo ka-hortagga shuruudaha dareeraha si loo yareeyo qulqulka qashinka inta badan xaddidan oo keliya methanol/ dareeraha-molecule-yar-yar oo aasaasi u ah isku-dhafka cagaaran guud ahaan.
2 Qaybaha jilicsan ee kala duwan ee polyurethane aan isocyanate ahayn
2.1 Polyether polyurethane
Polyether polyurethane (PEU) ayaa si weyn loo isticmaalaa sababtoo ah tamarta isku xirnaanta hoose ee ether bonds ee qaybta jilicsan ee cutubyada soo noqnoqda, wareeg sahlan, dabacsanaan heerkul hooseeya oo heer sare ah iyo caabbinta hydrolysis.
Kebir iyo al. polyether polyurethane la sameeyay oo leh DMC, polyetylen glycol iyo butanediol sida alaabta ceeriin, laakiin miisaanka kelli wuu hooseeyaa (7 500 ~ 14 800g / mol), Tg wuxuu ka hooseeyaa 0 ℃, barta dhalaaliduna sidoo kale way hoosaysay (38 ~ 48 ℃) , iyo xoogga iyo tilmaamayaasha kale way adkeyd in la daboolo baahiyaha isticmaalka. Kooxda cilmi-baarista ee Zhao Jingbo waxay adeegsadeen ethylene carbonate, 1, 6-hexanediamine iyo polyetylen glycol si ay u abuuraan PEU, kaas oo leh miisaan kelli ah oo ah 31 000g / mol, xoogga jilicsan ee 5 ~ 24MPa, iyo dhererka jebinta 0.9% ~ 1 388%. Miisaanka kelli ee taxanaha isku dhafan ee polyurethane caraf udgoon waa 17 300 ~ 21 000g / mol, Tg waa -19 ~ 10 ℃, barta dhalaalidu waa 102 ~ 110 ℃, xoogga xajinta waa 12 ~ 38MPa, iyo heerka soo kabashada laastikada of 200% elongation joogto ah waa 69% ~ 89%.
Kooxda cilmi-baarista ee Zheng Liuchun iyo Li Chuncheng waxay diyaariyeen dhexdhexaadiyaha 1, 6-hexamethylenediamine (BHC) oo leh dimethyl carbonate iyo 1, 6-hexamethylenediamine, iyo polycondensation oo leh unugyo yaryar oo kala duwan oo silsilad toosan ah iyo polytetrahydrofuranediols (Mn = 2 000). Taxane ah polyether polyurethane (NIPEU) oo leh dariiq aan isocyanate ahayn ayaa la diyaariyey, iyo dhibaatada isku dhafka ah ee dhexdhexaadiyeyaasha inta lagu jiro falcelinta ayaa la xalliyey. Qaab dhismeedka iyo sifooyinka polyether-ka dhaqameed (HDIPU) ee ay diyaarisay NIPEU iyo 1, 6-hexamethylene diisocyanate ayaa la barbardhigay, sida ku cad shaxda 1.
| Tusaale | Jajabka tirada adag ee qaybta adag/% | Miisaanka molecular/(g·mol^ (-1)) | Tusaha qaybinta miisaanka molecular | Xoog xajin/MPa | Kordhinta wakhtiga nasashada/% |
| 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 |
Shaxda 1
Natiijooyinka shaxda 1 waxay muujinayaan in kala duwanaanshaha qaabdhismeedka u dhexeeya NIPEU iyo HDIPU ay inta badan sabab u tahay qaybta adag. Kooxda urea ee ay dhaliso falcelinta dhinaca NIPEU waxay si aan kala sooc lahayn ugu dhex jirtaa silsiladda unugyada adag ee qaybta adag, jebinaysa qaybta adag si ay u samayso curaarta hydrogen ee la amray, taasoo keentay curaarta hydrogen daciifka ah ee u dhexeeya silsiladaha molecular ee qaybta adag iyo crystallinity hoose ee qaybta adag. , taasoo keentay kala soocida heerka hoose ee NIPEU. Natiijo ahaan, sifooyinkiisa makaanikada ayaa aad uga xun HDIPU.
2.2 Polyester Polyurethane
Polyester polyurethane (PETU) oo leh diol polyester sida qaybaha jilicsan ayaa leh biodegradability wanaagsan, biocompatibility iyo sifooyin farsamo, waxaana loo isticmaali karaa in lagu diyaariyo muraayadaha injineernimada unugyada, taas oo ah walxo biomedical ah oo leh rajooyin codsi oo weyn. Diolyada Polyester-ka ee sida caadiga ah loo isticmaalo qaybaha jilicsan waa polybutylene adipate diol, polyglycol adipate diol iyo polycaprolactone diol.
Markii hore, Rokicki et al. ka falceliyay carbonate ethylene leh diamine iyo diols kala duwan (1, 6-hexanediol,1, 10-n-dodecanol) si loo helo NIPU kala duwan, laakiin NIPU-da la isku daray ayaa miisaankeedu hooseeyo iyo Tg hoose. Farhadian iyo al. karbonateet polycyclic ah oo la diyaariyey iyadoo la adeegsanayo saliid abuur gabbaldayaha ah sida walxo ceeriin ah, ka dibna lagu qaso polyamines-ku saleysan bio, oo lagu dahaadhay saxan, laguna daaweeyay 90 ℃ 24 h si loo helo filim heerkulbeeye polyester polyurethane ah, taas oo muujisay xasillooni heerkuleed oo wanaagsan. Kooxda cilmi-baarista ee Zhang Liqun oo ka socota Jaamacadda Teknolojiyadda Koonfurta Shiinaha waxay soo saareen taxane diamines ah iyo kaarboonaydhyo wareeg ah, ka dibna lagu ururiyey dibasic acid biobased si ay u helaan polyester polyurethane biobased. Kooxda cilmi-baarista ee Zhu Jin ee Machadka Ningbo ee Cilmi-baarista Qalabka, Akademiyada Shiinaha ee Sayniska waxay diyaarisay diaminodiol qayb adag iyadoo la adeegsanayo hexadiamine iyo vinyl carbonate, ka dibna polycondensation leh dibasic acid unsaturated bio-based si loo helo taxane polyester polyurethane, kaas oo loo isticmaali karo rinjiga ka dib. daaweynta ultraviolet [23]. Kooxda cilmi-baarista ee Zheng Liuchun iyo Li Chuncheng waxay isticmaaleen adipic acid iyo afar diols aliphatic (butanediol, hexadiol, octanediol iyo decanediol) oo leh nambarada atomiga kaarboon ee kala duwan si ay u diyaariyaan diolyada polyester-ka ee u dhigma qaybo jilicsan; Koox ka mid ah polyester polyester-ka (PETU), oo lagu magacaabo ka dib tirada atamka kaarboon ee diols aliphatic, ayaa lagu helay dhalaalidda polycondensation oo leh qaybta adag ee hydroxy-sealed prepolymer ay diyaariyeen BHC iyo diols. Qalabka farsamada ee PETU waxa lagu muujiyay shaxda 2.
| Tusaale | Xoog xajin/MPa | modules laastikada/MPa | Kordhinta wakhtiga nasashada/% |
| 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 |
Shaxda 2
Natiijooyinku waxay muujinayaan in qaybta jilicsan ee PETU4 ay leedahay cufnaanta ugu sarreysa ee karbonyl, dammaanadda hydrogen ugu xooggan ee qaybta adag, iyo heerka ugu hooseeya ee kala-soocidda. Karistaleynta labada qaybood ee jilicsan iyo kuwa adag waa mid xaddidan, oo muujinaya dhibic dhalaalaysa oo hooseeya iyo xoogga jilicsanaanta, laakiin dhererka ugu sarreeya ee nasashada.
2.3 polycarbonate polyurethane
Polycarbonate polyurethane (PCU), gaar ahaan aliphatic PCU, waxay leedahay caabbinta hydrolysis heer sare ah, iska caabin oksaydh, xasilooni bayooloji wanaagsan iyo biocompatibility, waxayna leedahay rajooyin codsi oo wanaagsan oo ku saabsan biomedicine. Waqtigan xaadirka ah, inta badan NIPU-da la diyaariyey waxay isticmaashaa polyeter polyols iyo polyester polyols sida qaybo jilicsan, waxaana jira warbixino cilmi baaris oo yar oo ku saabsan polycarbonate polyurethane.
Polyurethane-ka polycarbonate-ka ee aan isocyyanate-ka ah ee ay diyaariyeen kooxda Tian Hengshui ee Tian Hengshui ee Jaamacadda Tignoolajiyada ee Koonfurta Shiinaha waxay leedahay miisaan kelli ah oo ka badan 50 000 g/mol. Saamaynta xaaladaha falcelinta ee miisaanka molecular ee polymer ayaa la darsay, laakiin sifooyinkiisa makaanikada ah lama soo sheegin. Zheng Liuchun iyo kooxda cilmi baarista Li Chuncheng waxay diyaariyeen PCU iyaga oo isticmaalaya DMC, hexanediamine, hexadiol iyo polycarbonate diols, waxaana loo magacaabay PCU iyadoo loo eegayo jajabka tirada badan ee qaybta adag ee ku celcelinta. Qalabka farsamada waxa lagu muujiyay shaxda 3.
| Tusaale | Xoog xajin/MPa | modules laastikada/MPa | Kordhinta wakhtiga nasashada/% |
| 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 |
Shaxda 3
Natiijooyinku waxay muujinayaan in PCU uu leeyahay miisaan sare oo unugyo ah, ilaa 6 × 104 ~ 9 × 104g/mol, barta dhalaalaysa ilaa 137 ℃, iyo xoogga xajinta ilaa 29 MPa. PCU-ga noocaan ah waxaa loo isticmaali karaa sidii caag adag ama elastomer ahaan, kaas oo leh rajo wanaagsan oo ku saabsan goobta biomedical (sida qalabka injineernimada unugyada bini'aadamka ama qalabka la geliyo xididdada wadnaha).
2.4 Hybrid polyurethane aan isocyanate ahayn
Hybrid non-isocyanate polyurethane ( hybrid NIPU) waa soo bandhigida resin epoxy, acrylate, silica ama kooxaha siloxane qaabdhismeedka molecular polyurethane si ay u sameeyaan shabakad isku xiran, hagaajinta waxqabadka polyurethane ama siiso polyurethane hawlo kala duwan.
Feng Yuelan iyo al. waxay ka falcelisay saliid soybean ah oo ku salaysan bio-ku-salaysan CO2 si ay u soo saarto pentamonic cyclic carbonate (CSBO), waxayna soo bandhigtay bisphenol A diglycidyl ether (epoxy resin E51) oo leh qaybo silsilado adag ah si loo sii wanaajiyo NIPU ay samaysay CSBO oo lagu xoojiyay amine. Silsiladda molecular waxay ka kooban tahay silsilad dabacsan oo dheer oo ah oleic acid/linoleic acid. Waxa kale oo ay ka kooban tahay qaybo silsilado adag oo adag, si ay u yeelato awood farsamo oo sare iyo adag tahay. Cilmi-baarayaasha qaarkood ayaa sidoo kale soo saaray saddex nooc oo prepolymers NIPU ah oo leh kooxaha dhamaadka furan iyada oo loo marayo falcelinta heerka furitaanka ee diethylene glycol bicyclic carbonate iyo diamine, ka dibna waxay ku falceliyeen polyester unsaturated si ay u diyaariyaan polyurethane jilicsan oo leh shaqo is-bogsiin, oo si guul leh u ogaaday is-xakamaynta sare. -wax ku oolnimada bogsashada ee NIPU jilicsan. Hybrid NIPU ma aha oo kaliya in uu leeyahay sifooyinka NIPU guud, laakiin sidoo kale waxa laga yaabaa in ay leeyihiin adhesion ka fiican, acid iyo alkali iska caabin daxalka, caabin dareere iyo xoogga farsamada.
3 Muuqaalka
NIPU waa la diyaariyaa iyada oo aan la isticmaalin isocyanate sun ah, waxaana hadda lagu bartaa qaabka xumbo, dahaarka, dhejiska, elastomer iyo alaabooyin kale, waxayna leedahay rajooyin badan oo codsi ah. Si kastaba ha ahaatee, intooda badani wali waxay ku kooban yihiin cilmi-baarista shaybaarka, mana jiraan wax soo saar ballaaran. Intaa waxaa dheer, iyada oo la hagaajinayo heerarka nolosha dadka iyo koritaanka joogtada ah ee baahida, NIPU oo leh hal shaqo ama hawlo badan ayaa noqday jihada cilmi-baarista ee muhiimka ah, sida bakteeriyada, is-dayactirka, xusuusta qaabka, ololka dabka, caabbinta kulaylka sare iyo sidaas oo kale. Sidaa darteed, cilmi-baarista mustaqbalka waa in ay fahmaan sida loo jebiyo dhibaatooyinka muhiimka ah ee warshadaynta oo ay sii wadaan sahaminta jihada diyaarinta NIPU-da shaqeyneysa.
Waqtiga boostada: Agoosto-29-2024