Ho bapisa li-Isocyanate le liraba tsa metsi tse arabelang HTPB le CTBN
Lintlha tsa Bohlokoa
- Kopanya lirabara tsa metsi tse seng tsa polar le li-isocyanate tse nkhang hamonate ho haha thepa e theko e tlase, e sa keneleng metsi e nang le matla a phahameng.
- Kopanya li-isocyanate tsa aliphatic le li-rubber tsa metsi ho etsa li-sealant tse hlakileng, tse sa keneng mochesong oa leholimo tse hanelang tšenyo ea letsatsi.
- Boloka ea hau Khemikhale ea NCO index pakeng tsa 1.02 le 1.08 ho netefatsa ho fola ka botlalo le ts'ebetso e matla.
'Mapa oa Khemistri le Ts'ebetso
Reactivity ea Sehlopha sa Terminal le Kinetics
O tlameha ho hokahanya lebelo la karabelo la isocyanate eo o e khethileng le lihlopha tse itseng tsa terminal tsa rabara ea hao ea metsi. Polybutadiene e fedisitsweng ke Hydroxyl (HTPB) e arabela hantle le diisocyanate, ha liraba tse felisitsoeng ke amine (ATBN) arabela hang-hang ho theha likhokahano tse matla tsa polyurea. Ha o theha diisocyanate tse sa lekanang joalo ka IPDI, li-catalyst tse itseng li fetola karabelo ea sehlopha. Mohlala, trifluoroacetic acid e kenya tšebetsong sehlopha sa mantlha sa isocyanate ho feta sa bobeli. Tlhaho ea lik'hemik'hale ea lihlopha tse haufi tsa lehlakore e khanna khetho ena ea kinetic ho fapana le tšitiso ea steric.
Ho bapisa diparamitha tsa Polarity le Tharollo
Ho bapisa li-Isocyanate le Reactive Liquid Rubber (HTPB khahlanong le CTBN) ho hloka tlhahlobo e hlokolosi ea liparamente tsa ho qhibiliha. Mekokotlo ea polybutadiene e seng polar e hanela ho kopana le li-isocyanate tse polar, tse nkhang hamonate. U ka sebelisa tataiso e latelang ho kopanya mekokotlo le lipheko:
| Mofuta oa Rabara ea Metsi | Sehlopha sa Ts'ebetso | Papali e Loketseng ea Isocyanate | Melemo ea Bohlokoa ea Tshebetso |
|---|---|---|---|
| Non-Polar (HTTPB) | -OH | TDI / MDI / IPDI | Phoso e Phahameng ea Hydrosicity |
| Polar (CTBN) | -COOH | MDI / Epoxy-Hybrids | Khanyetso e Phahameng ea Tšusumetso |
Jiometri ea Isocyanate le Sebopeho sa Karolo e Thata
Ho tšoana ha limolek'hule tsa Isocyanate ho etsa qeto ea ho kristalea ha likarolo tse thata le karohano ea mekhahlelo. Meaho e nang le monko o tšoanang joalo ka stack ea 4,4'-MDI e tiile, e theha libaka tse thata tse eketsang matla a mechini. Li-monomer tse sa lekanang joalo ka TDI kapa IPDI li sitisa ho paka haufi, li fokotsa viscosity ea resin le ho ntlafatsa ho tenyetseha ha mocheso o tlase. U ka ntlafatsa ho tiea ha polymer ka kakaretso ka ho leka-lekanya li-geometri tse tšoanang le tse sa lekanang.
Ho bapisa Li-Isocyanate le Liraba tsa Metsi a Reactive (Litsamaiso tsa HTPB)
Polybutadiene e fedisitsweng ke hydroxyl (HTPB) e na le mokokotlo wa hydrocarbon o sa thekeseleng haholo, o sa tshoseng metsi. O tlameha ho kgetha dipheko tse tsamaellanang ho thibela mongobo le ho boloka botsitso ba sebopeho. Ho bapisa di-Isocyanate le Diraba tsa Metsi tse Reactive (Ditsamaiso tsa HTPB di hloka ho sekaseka tshebetso ya dikhemikhale le ditlhoko tsa ho qetela tsa metjhini.
MDI le TDI bakeng sa Li-Elastomer tsa Hydrophobic
Diisocyanate tse nkhang hamonate joalo ka diphenylmethane diisocyanate (MDI) le toluene diisocyanate (TDI) e arabela ka potlako ka lihlopha tsa qetello tsa HTPB hydroxyl. Mefuta ena e nkhang hamonate e fana ka matla a 'mele a ikhethang le litšenyehelo tse tlase. MDI e etsa likarolo tse teteaneng, tse thata tse kang kristale haholo ka har'a marang-rang a elastomeric. Pakete ena e teteaneng e eketsa matla a ho taboha le ho eketsa ho hanyetsa ho taboha.
Lesapo la mokokotlo la HTPB (Le se nang polar) + MDI/TDI (Le monko o monate) ===> Elastomer ea Sebopeho sa Hydrophobic TDI e fana ka viscosity e tlase ea pele ho feta MDI. U ka tšela metsoako e thehiloeng ho TDI ka har'a liforomo tse rarahaneng habonolo. Leha ho le joalo, TDI e bontša khatello e phahameng ea mouoane. U tlameha ho sebetsana le TDI ka moea o kenang o eketsehileng ho sireletsa basebetsi.
| Mofuta oa Isocyanate | Boemo ba ho thothomela | Sekhahla sa Reaction | Molemo oa Bohlokoa |
|---|---|---|---|
| MDI | Mahareng - Holimo | Kapele | Matla a Phahameng a ho Tenyetseha le ho Hahola |
| TDI | Tlase Haholo | Ka Potlako Haholo | Ho Tlatsa Hlobo Habonolo |
Lithethefatsi tsena ka bobeli tse nkhang hamonate li boloka litšobotsi tsa tlhaho tsa HTPB tse thibelang metsi. Li sireletsa elastomer ea hau ea ho qetela khahlanong le ho monngoa ha metsi, li-acid tse fokolang le li-alkali tse metsi.
Hlokomela: Likarolo tse thata tse monko o monate lia senyeha tlas'a khanya ea ultraviolet (UV). Sebelisa MDI le TDI haholo-holo lits'ebetsong tse patiloeng, tse koahetsoeng, kapa tse ka tlung moo ho pepesehelang UV ho sa feleng.
IPDI le HDI bakeng sa Diforomo tse Tsitsitseng ka Leseli
Li-isocyanate tsa Aliphatic li rarolla mathata a botsofali ba mocheso le ho senyeha ha leseli. Isophorone diisocyanate (IPDI) le hexamethylene diisocyanate (HDI) li hanela mahlaseli a UV ka ho feletseng. Li thibela ho ba mosehla le ho petsoha ha bokaholimo nakong ea ho pepesehela kantle nako e telele.
IPDI e na le lihlopha tse peli tsa NCO tse sa lekanang. Sehlopha sa mantlha sa NCO se arabela butle, ha sehlopha sa bobeli sa NCO se arabela kapele tlas'a mocheso o phahameng. U ka sebelisa phapang ena ea kinetic ho laola bophelo ba hau ba pitsa le ts'ebetso ea ho lahla.
HDI e fana ka ho tenyetseha ho otlolohileng. Sebopeho sa yona sa aliphatic se lekanang se fokotsa mocheso wa karohano ya microphase, e leng se bolokang ho tenyetseha ho fihlela maemong a ka tlase ho lefela.
- Melemo ea IPDI: Bophelo bo bolelele ba pitsa, lipotoloho tse laolehang tsa ho folisa, botsitso bo phahameng ba mocheso.
- Melemo ea HDI: Ho tenyetseha ho phahameng ka mocheso o tlase, ho hanyetsa mahlaseli a kotsi a UV ho babatsehang, le ho ba le viscosity e tlase.
Ho bapisa Li-Isocyanate le Li-Reactive Liquid Rubber (HTPB le li-curative tsa aliphatic li hlahisa ho hlaka ha mahlo, botsitso ba 'mala, le li-sealant tse hanelang boemo ba leholimo.
Ho Hlophisa le ho Ntlafatsa Ts'ebetso ea Prepolymer le Stoichiometry
Ho kopanya ka ho toba ka ho qotsa hanngoe feela ho ka baka liketso tse sa laoleheng tsa exothermic le karohano ea mekhahlelo. U ka thibela mathata ana ka ho kopanya Prepolymer e felisitsoeng ke NCO pele. Ho hlophisoa ha prepolymer ho fokotsa tlhahiso yohle ya mocheso nakong ya ho phekolwa ha ho qetela mme ho fokotsa ho ntsha ha monomer e feto-fetohang.
- Tokisetso ea Karabelo: Tlatsa sehatsetsi sa hao ka resin e ommeng ya HTPB.
- Ho Tlosa Mongobo: Tlosa gas ka vacuum ho 90°C ho tlosa mongobo o setseng. Metsi a arabela le lihlopha tsa NCO, a etsa lipululana tsa carbon dioxide le lintlha tse fokolang tsa urea.
- Ho eketsa isocyanate: Kenya diisocyanate eo u e khethileng tlas'a kobo e omileng ea naetrojene.
- Katoloso ea Ketane e Laoloang: Boloka mocheso o pakeng tsa 70°C le 80°C ho fihlela dikahare tsa NCO di tsitsitse.
Mohato oa 1: Isocyanate e Feteletseng + HTPB ===> Prepolymer e Felisitsoeng ke NCO + Monomer e sa Lefelloeng Mohato oa 2: Prepolymer + Extender ea Chain ===> Marang-rang a Polyurethane a Folisitsoeng O tlameha ho bala stoichiometry ea hau ka hloko. Boloka index ea NCO ka kakaretso (karolelano e lekanang ea lihlopha tsa NCO ho OH) ka har'a moeli oa 1.03 ho isa ho 1.06.
$$\text{NCO Index} = \frac{\text{Kakaretso ya Dilekana tsa NCO}}{\text{Kakaretso ya Dilekana tsa OH}}$$
Index ea NCO e ka tlase ho 1.00 e siea liketane tsa HTPB tse sa arajoang. Limolek'hule tsena tsa metsi tse sa arajoang li sebetsa e le li-plasticizer tse sa batleheng, tse fokotsang modulus ea hau ea ho tensile le ho senya khanyetso ea lik'hemik'hale. Ka lehlakoreng le leng, index ea NCO e kaholimo ho 1.10 e baka ho hokahanya ho feteletseng. Li-crosslink tse ngata haholo li baka ho hloleha ho brittle tlas'a ho jara ha matla a matla. Stoichiometry e nepahetseng e tiisa ts'ebetso e phahameng ka ho fetisisa.
Maano a Khetho ea CTBN, ATBN, le HTBN
Lihlopha tsa terminal tsa Carboxyl, amine, le hydroxyl tse holim'a masapo a rabara a nitrile li hloka maano a kgetho a reretsoeng. U ka ntlafatsa haholo ho tiea ha ho robeha, ho hanyetsa lik'hemik'hale, le ts'ebetso ea mocheso ka ho kopanya liraba tsena tse sebetsang le li-isocyanate tse nepahetseng.
Mefuta e tsoakiloeng ea Epoxy-Polyurethane e nang le CTBN le MDI
Butadiene acrylonitrile (CTBN) e fedisitsweng ke carboxyl e na le dihlopha tsa terminal carboxylic acid (-COOH) le mokokotlo wa polar nitrile. Dikarabelo tse tobileng pakeng tsa di-carboxylic acid le diisocyanate di hlahisa dikamano tse sa tsitsang tsa anhydride mme di lokolla kgase ya carbon dioxide. O ka fedisa dipululana tsa kgase ka ho kopanya marangrang a epoxy-polyurethane hybrid ho ena le hoo.
CTBN + Epoxy Resin e Feteletseng ===> Epoxy-Terminated Rubber Prepolymer Epoxy Prepolymer + 4,4'-MDI + Chain Extender ===> Toughened Hybrid Matrix Taba ea pele, kopanya CTBN ka resin e ngata ea epoxy ho hlahisa rabara e felisitsoeng ke epoxy. Ka mor'a moo, eketsa 4,4'-MDI le extender ea ketane ea diol ho haha lesapo la mokokotlo la polyurethane le hokahaneng ho potoloha libaka tsa rabara.
Keletso ea Setsebi: Boloka dikahare tsa acrylonitrile (AN) kahare ho CTBN pakeng tsa 18% le 26%. Mofuta ona o ikhethileng oa AN o khothalletsa karohano ea mekhahlelo nakong ea ho fola. Libaka tse nyane tsa rabara tse boholo ba micron lia tsoa ka har'a matrix, li theha litšitiso tse sebetsang khahlanong le ho ata ha mapetso.
MDI e fana ka dikarolo tse thata tse monko o monate tse tlamang matrix ya polar. Ha kgatello e matla e fihla ho motsoako o phekotsweng, di-domain tsena tse hasaneng tsa CTBN di monya matla a tshusumetso. O fumana matla a ho robeha a phahameng ntle le ho senya botsitso ba mechini ya mocheso kapa modulus ya ho tensile.
Sebopeho sa Urea sa Amine-Isocyanate se tobileng se nang le ATBN
Butadiene acrylonitrile (ATBN) e fedisitsweng ke amine e na le dihlopha tsa pheletso tsa amine tsa mantlha kapa tsa bobedi tse arabelang (-NH2 kapa -NHR). Di-amine di arabela le diisocyanate hang-hang mochesong wa kamore. Di bopa dikgokelo tse matla tsa polyurea ntle le ho hloka di-catalyst tsa maiketsetso.
| Tekanyo ea Tshebetso | Polyurethane (HTPB/MDI) | Polyurea (ATBN/MDI) |
|---|---|---|
| Lebelo la Karabelo | E itekanetseng (Metsotso ho isa Lihora) | Ka Potlako e Phahameng (Metsotsoana ho isa Metsotso) |
| Moeli oa Thermal | 100°C - 120°C | 150°C - 180°C |
| Ho Kopanngoa ha Haedrojene | Litlamo tsa Urea/Urethane tse le 'Ngoe | Litlamo tsa Urea tse teteaneng tsa Bidentate |
| Ho ba le kutloelo-bohloko ha mongobo | Holimo (Kotsi ea ho thehoa ha khase) | Tlase (Amine e feta metsi) |
Ha o bapisa di-Isocyanate le dirubber tsa metsi tse arabelang (Mekhoa ea HTPB kapa mekhoa ea ATBN), o tlameha ho fetola disebediswa tsa hao tsa ho kopanya ho sebetsana le dipharologanyo tsena tsa kinetic. ATBN e arabela ka potlako hoo o tlamehang ho sebedisa dihlooho tse ikgethang tsa ho kopanya tse nang le kgatello e phahameng.
ATBN (Lipheletso tsa Amine) + Isocyanate (NCO) ===> Likarolo tse Thata tsa Polyurea (Kopanyo ea Bidentate) Libaka tse thata tsa polyurea tse hlahang li theha maqhama a matla a bidentate hydrogen. Lihokelo tsena tsa 'mele li phahamisa ntlha ea ho senyeha ha mocheso oa elastomer ea hau ka holimo ho 150°C. Hape u felisa mathata a ho utloa mongobo nakong ea ts'ebetso. Lihlopha tsa pheletso ea amine li arabela ka NCO kapele haholo ho feta metsi a tikolohong.
Ho lumellana ha HTBN ho Litsamaiso tse Hanelang Mafura
Butadiene acrylonitrile e fedisitsweng ke hydroxyl (HTBN) e kopanya ts'ebetso ea hydroxyl (-OH) le mokokotlo oa nitrile oa polar. Lirabara tse seng tsa polar li hlōleha kapele ha li pepesetsoa mafura a seng a polar, li-solvents tse nkhang hamonate, kapa maro a hydraulic. Lihlopha tsa acrylonitrile tsa polar ho HTBN li leleka li-hydrocarbon, li sireletsa elastomer ea hau khahlanong le ho ruruha ha li-solvent.
HTBN (Polar Backbone) + IPDI/MDI ===> Thibelo ea Hydrocarbon e Hanelang Mafura O tlameha ho bapisa HTBN le diisocyanate tse tsamaellanang ho haha litiiso tse tšoarellang, li-gasket le li-liner tsa litanka tsa mafura:
- Kopanya HTBN le MDI: U fihlella ho tiea ho hoholo ha mechini, ho hanyetsa meokho e mengata, le matla a matala a potlakileng bakeng sa li-gasket tsa indasteri.
- Kopanya HTBN le IPDI: U fumana lipente tsa tanka ea mafura tse tenyetsehang, tse tsitsitseng ka UV tse hanelang ho petsoha tlas'a liphetoho tse matla tsa mocheso.
O ka fetola dikahare tsa nitrile ho HTBN ho ntlafatsa kganyetso ya solvent. Maemo a phahameng a acrylonitrile a eketsa polarity le ho eketsa kganyetso ya mafura. Leha ho le jwalo, polarity e phahameng e boetse e eketsa viscosity ya resin ya pele. O lokela ho futhumatsa HTBN ho fihlela ho 50°C nakong ya ho tlosa khase ho fokotsa viscosity ya ho e sebetsana pele o hlahisa diisocyanate eo o e kgethileng.
Liparamitha tsa Bohlokoa tsa ho Theha le ho Sebetsa
Litekanyetso tsa Stoichiometric le Taolo ea Index ea NCO
O tlameha ho laola ka tieo karolelano ea stoichiometric pakeng tsa lihlopha tse mafolofolo tsa isocyanate le lihlopha tsa qetello tsa rabara. Shebana le index ea NCO pakeng tsa 1.02 le 1.08 ho netefatsa ho kopanya lik'hemik'hale ka botlalo. Index e ka tlase ho 1.00 e siea li-oligomer tse sa arajoang. Limolek'hule tsena tse lokolohileng li sebetsa e le li-plasticizer tse sa batleheng 'me li fokotsa botšepehi ba sebopeho. Ka lehlakoreng le leng, index e ka holimo ho 1.10 e baka ho kopanya ho feteletseng, e leng se etsang hore elastomer ea hau e phekotsoeng e be bonolo.
Sebopeho sa Sebaka le Karohano ea Microphase
Karohano ea microphase e laola ka ho toba ts'ebetso ea mechini ea matrix ea hau ea polymer e phekotsoeng. Mekokotlo ea rabara e seng ea polar ka tlhaho e leleka likarolo tse thata tsa urethane kapa urea. U ka lokisa ho se lumellane hona ha lik'hemik'hale ho khanna ho iketsa ha u ntse u lokisa. Libaka tse thata tse hasaneng li sebetsa e le lihokelo tsa 'mele ho eketsa matla a ho hula. Ho sa le joalo, libaka tse bonolo tsa rabara tse tsoelang pele li boloka ho tenyetseha ha mocheso o tlase le ho monya matla a tšusumetso e matla.
Ho Sebetsa Viscosity le Ntlafatso ea Bophelo ba Pitsa
Ha o bapisa di-Isocyanate le di-Reactive Liquid Rubber (di-formulations tsa HTPB, viscosity e phahameng ya pele hangata e sitisa ho tlatsa le ho ntša mosi ka katleho ka hlobo. Ditharollo tse sa arabeleng di fokotsa ho teneha, empa di baka dikgeo tse fokolang nakong ya mouwane. Ho ena le hoo, HTPB e boima ba dimolek'hule bo tlase haholo e sebetsa e le motswako o arabelang dibopehong tsa polymer, e dumella phokotso e sebetsang ya ho teneha ha e ntse e boloka thepa ya mantlha ya mechine le ya mmele ya thepa.
Keletso: Chesa rabara ea hao ea metsi ho fihlela ho 50°C pele u eketsa moriana ho eketsa bophelo ba pitsa le ho potlakisa ho lokolloa ha lipululana.
- Bapisa HTPB e seng polar le MDI kapa TDI ho eketsa ho se tshabe metsi le ho tenyetseha ha mocheso o tlase ka mokhoa o theko e tlase.
- Kopanya HTPB le aliphatic IPDI kapa HDI bakeng sa khanyetso e phahameng ea UV le bophelo bo bolelele ba pitsa.
- Sebelisa liraba tsa nitrile (CTBN, ATBN, HTBN) lits'ebetsong tsa polar ho eketsa ho tiea ha ho robeha le ho hanyetsa oli.
- Laola stoichiometry ea NCO ka tieo. Litekanyetso tse nepahetseng li thibela li-oligomer tse sa arajoang ho fokolisa elastomer ea hau.
LBH
U khetha joang pakeng tsa MDI le IPDI bakeng sa litsamaiso tsa HTPB?
Keletso e Potlakileng: Bapisa phekolo ea hau le tikoloho ea hau ea kopo.
Kgetha MDI ha o hloka matla a ho thaepa a phahameng le theko e tlase bakeng sa ditshebediso tsa ka tlung. Kgetha IPDI bakeng sa diforomo tsa kantle tse hlokang botsitso ba UV le bophelo bo bolelele ba pitsa.
Ke hobane'ng ha u lokela ho boloka index ea NCO pakeng tsa 1.02 le 1.08?
Karolelano ena e ikgethang e netefatsa ho kopanya ka botlalo dikhemikhale. E thibela rabara ya mokelikeli e sa arajoang ho nolofatsa matrix ya hao mme e thibela ho kopanya ho feteletseng ho hlahisang elastomer e brittle.
CTBN e ntlafatsa ho tiea ha ho robeha joang ho epoxy-polyurethane hybrids?
CTBN e kena libakeng tse nyane tsa rabara nakong ea ho fola. Likaroloana tsena tsa rabara tse nyenyane haholo li monya matla a tšusumetso 'me li thibela ho ata ha mapetso ho pholletsa le matrix ea hau ea polymer e folisitsoeng.