Ihe a na-akpọpolyurethanebụ mkpọbiri nke polyurethane, nke a na-emepụta site na mmeghachi omume nke polyisocyanates na polyols, ma nwee ọtụtụ otu amino ester ugboro ugboro (- NH-CO-O -) na yinye molekul. Na resin polyurethane emepụtara n'ezie, na mgbakwunye na otu amino ester, enwere otu dịka urea na biuret. Polyols so na molekul ogologo nwere otu hydroxyl na njedebe, nke a na-akpọ "ngalaba yinye dị nro", ebe a na-akpọ polyisocyanates "ngalaba yinye siri ike".
N'ime resin polyurethane nke akụkụ yinye dị nro na nke siri ike na-emepụta, naanị obere pasentị bụ amino acid esters, yabụ ọ nwere ike ọ gaghị adabara ịkpọ ha polyurethane. N'ụzọ sara mbara, polyurethane bụ ihe mgbakwunye nke isocyanate.
Ụdị isocyanates dị iche iche na-emeghachi omume na polyhydroxy compounds iji mepụta ụdị polyurethane dị iche iche, si otú a na-enweta ihe polymer nwere ihe dị iche iche, dị ka plastik, roba, mkpuchi, eriri, ihe nrapado, wdg.
Rubber polyurethane bụ nke ụdị rọba pụrụ iche, nke a na-eme site na iji polyether ma ọ bụ polyester megharịa ya na isocyanate. E nwere ọtụtụ ụdị dị iche iche n'ihi ụdị ihe eji arụ ọrụ dị iche iche, ọnọdụ mmeghachi omume, na ụzọ njikọta. Site na echiche nhazi kemịkalụ, e nwere ụdị polyester na polyether, sitekwa na echiche usoro nhazi, e nwere ụdị atọ: ụdị ngwakọta, ụdị nkedo, na ụdị thermoplastic.
A na-ejikarị polyester linear ma ọ bụ polyether eme ihe na diisocyanate iji mepụta prepolymer dị obere, nke a na-etinye n'ime usoro ịgbatị agbụ iji mepụta polima dị arọ molekul. Mgbe ahụ, a na-agbakwunye ihe ndị na-ejikọta ihe kwesịrị ekwesị ma kpoo ọkụ iji gwọọ ya, na-aghọ roba vulcanized. A na-akpọ usoro a prepolymerization ma ọ bụ usoro nzọụkwụ abụọ.
O nwekwara ike iji otu ụzọ - ịgwakọta polyester linear ma ọ bụ polyether ozugbo na diisocyanates, ihe ndọtị agbụ ígwè, na ihe ndị na-ejikọ ọnụ iji malite mmeghachi omume ma mepụta roba polyurethane.
Nkewa A dị na molekul TPU na-eme ka agbụ ígwè macromolecular dị mfe ịtụgharị, na-enye roba polyurethane ezigbo ike, na-ebelata ebe dị nro na ebe mgbanwe nke abụọ nke polima, ma na-ebelata ike ya na ike igwe. Nkewa B ga-ejikọta ntụgharị nke agbụ ígwè macromolecular, na-eme ka ebe dị nro na ebe mgbanwe nke abụọ nke polima dịkwuo elu, na-ebute mmụba na ike na ike igwe, yana mbelata na ike. Site na ịgbanwe oke molar dị n'etiti A na B, enwere ike ịmepụta TPU nwere ihe dị iche iche nke mechanical. Nhazi njikọ nke TPU agaghị atụle njikọ mbụ, kamakwa njikọ nke abụọ nke njikọ hydrogen mepụtara n'etiti molekul. Njikọ njikọ nke polyurethane dị iche na nhazi vulcanization nke roba hydroxyl. A na-ahazi otu amino ester ya, otu biuret, otu urea formate na otu ọrụ ndị ọzọ na ngalaba agbụ ígwè siri ike na nke dị n'otu oge, na-ebute nhazi netwọk nkịtị nke roba, nke nwere ezigbo ike iyi na ihe ndị ọzọ dị mma. Nke abụọ, n'ihi ọnụnọ nke ọtụtụ otu ọrụ dị iche iche dịka urea ma ọ bụ otu carbamate na roba polyurethane, njikọ hydrogen nke e guzobere n'etiti agbụ molekul nwere ike dị elu, njikọ njikọta nke abụọ nke njikọ hydrogen mepụtara nwekwara mmetụta dị ukwuu na njirimara nke roba polyurethane. Njikọ njikọta nke abụọ na-eme ka roba polyurethane nwee njirimara nke elastomers thermosetting n'otu aka, n'aka nke ọzọ, njikọ njikọta a abụghị njikọ njikọta n'ezie, na-eme ka ọ bụrụ njikọ njikọta mebere emebe. Ọnọdụ njikọ njikọta dabere na okpomọkụ. Ka okpomọkụ na-abawanye, njikọ njikọta a na-ebelata nwayọ ma na-apụ n'anya. Polymer nwere ụfọdụ mmiri mmiri ma enwere ike itinye ya na nhazi thermoplastic. Mgbe okpomọkụ na-ebelata, njikọ njikọta a na-agbake nwayọ nwayọ ma na-etolite ọzọ. Mgbakwunye nke obere ihe na-ejupụta na-eme ka anya dị n'etiti molekul dịkwuo elu, na-ebelata ikike ịmepụta njikọ hydrogen n'etiti molekul, ma na-eduga na mbelata dị nkọ na ike. Nnyocha egosila na usoro nkwụsi ike nke otu ọrụ dị iche iche na roba polyurethane site na elu ruo ala bụ: ester, ether, urea, carbamate, na biuret. N'oge usoro ịka nká nke roba polyurethane, nzọụkwụ mbụ bụ imebi njikọ dị n'etiti biuret na urea, wee mebie njikọ carbamate na urea, ya bụ, mgbawa nke isi yinye.
01 Ime ka ọ dị nro
Elastomers nke polyurethane, dịka ọtụtụ ihe polymer, na-eme ka ọ dị nro ma na-agbanwe site na ọnọdụ elastic gaa na ọnọdụ mmiri viscous, nke na-ebute mbelata ngwa ngwa na ike mekaniki. Site na echiche kemịkalụ, okpomọkụ dị nro nke elasticity na-adaberekarị na ihe ndị dị ka ihe mejupụtara kemịkalụ ya, ibu molekul dị n'otu, na njupụta njikọta.
N'ozuzu, ịbawanye ibu molekul dị n'otu, ịbawanye ike nke akụkụ siri ike (dịka itinye mgbanaka benzene n'ime molekul) na ọdịnaya nke akụkụ siri ike, na ịbawanye njupụta njikọta niile bara uru maka ịbawanye okpomọkụ na-eme ka ọ dị nro. Maka elastomers thermoplastic, nhazi molekul bụ nke kwụ ọtọ, okpomọkụ na-eme ka elastomer dị nro na-abawanyekwa mgbe a mụbara ibu molekul dị n'otu.
Maka polyurethane elastomers jikọtara ọnụ, njupụta njikọ na-enwe mmetụta dị ukwuu karịa ibu molekul dị n'otu. Ya mere, mgbe ị na-emepụta elastomers, ịbawanye ọrụ nke isocyanates ma ọ bụ polyols nwere ike ịmepụta nhazi njikọ kemịkalụ netwọkụ kwụsiri ike na ụfọdụ molekul elastic, ma ọ bụ iji oke isocyanate mepụta nhazi njikọ isocyanate kwụsiri ike na ahụ elastic bụ ụzọ dị ike isi melite iguzogide okpomọkụ, iguzogide mgbaze, na ike igwe nke elastomer.
Mgbe ejiri PPDI (p-phenyldiisocyanate) mee ihe dị ka ihe e ji arụ ọrụ, n'ihi njikọ kpọmkwem nke otu isocyanate abụọ na mgbanaka benzene, akụkụ siri ike e guzobere nwere ọdịnaya mgbanaka benzene dị elu, nke na-eme ka ike nke akụkụ siri ike ka mma ma si otú a na-eme ka iguzogide okpomọkụ nke elastomer dịkwuo mma.
Site n'echiche anụ ahụ, okpomọkụ dị nro nke elastomers dabere na oke nkewa microphase. Dịka akụkọ si kwuo, okpomọkụ dị nro nke elastomers ndị na-anaghị agafe oke microphase dị obere nke ukwuu, yana okpomọkụ nhazi nke naanị ihe dị ka 70 ℃, ebe elastomers ndị na-agafe oke microphase nwere ike iru 130-150 ℃. Ya mere, ịbawanye ogo nkewa microphase na elastomers bụ otu n'ime ụzọ dị irè iji melite iguzogide okpomọkụ ha.
Enwere ike imeziwanye ogo nkewa microphase nke elastomers site na ịgbanwe nkesa oke molekul nke akụkụ yinye na ọdịnaya nke akụkụ yinye siri ike, si otú a na-eme ka iguzogide okpomọkụ ha ka mma. Ọtụtụ ndị nchọpụta kwenyere na ihe kpatara nkewa microphase na polyurethane bụ enweghị nkwekọ thermodynamic n'etiti akụkụ dị nro na nke siri ike. Ụdị nkewa yinye, akụkụ siri ike na ọdịnaya ya, ụdị akụkụ dị nro, na njikọ hydrogen niile nwere mmetụta dị ukwuu na ya.
Ma e jiri ya tụnyere ihe ndọtị nke diol chain, ihe ndọtị nke diamine chain dị ka MOCA (3,3-dichloro-4,4-diaminodiphenylmethane) na DCB (3,3-dichloro-biphenylenediamine) na-etolite ọtụtụ otu amino ester polar na elastomers, enwere ike ịmepụta njikọ hydrogen karịa n'etiti akụkụ siri ike, na-eme ka mmekọrịta dị n'etiti akụkụ siri ike dịkwuo elu ma na-eme ka ọkwa nkewa microphase dị mma na elastomers; Ihe ndọtị nke a na-esi ísì ụtọ dị ka p, p-dihydroquinone, na hydroquinone bara uru maka nhazi na njikota nke akụkụ siri ike, si otú a na-eme ka nkewa microphase nke ngwaahịa dịkwuo mma.
Akụkụ amino ester nke aliphatic isocyanates mepụtara nwere ezigbo ndakọrịta na akụkụ dị nro, na-eme ka akụkụ siri ike karị na-agbaze na akụkụ dị nro, na-ebelata ogo nkewa microphase. Akụkụ amino ester nke aromatic isocyanates mepụtara enweghị ndakọrịta zuru oke na akụkụ dị nro, ebe ogo nkewa microphase dị elu. Polyolefin polyurethane nwere nhazi nkewa microphase zuru oke n'ihi eziokwu ahụ bụ na akụkụ dị nro anaghị emepụta njikọ hydrogen na njikọ hydrogen nwere ike ime naanị na akụkụ siri ike.
Mmetụta nke njikọ hydrogen na ebe dị nro nke elastomers dịkwa oke mkpa. Ọ bụ ezie na polyethers na carbonyls dị na mpaghara dị nro nwere ike ịmepụta ọtụtụ njikọ hydrogen na NH na mpaghara siri ike, ọ na-emekwa ka okpomọkụ dị nro nke elastomers dịkwuo elu. A kwadoro na njikọ hydrogen ka na-ejigide 40% na 200 ℃.
02 Njedebe okpomọkụ
Otu amino ester na-emebi ihe ndị a na oke okpomọkụ:
- RNHCOOR – RNC0 HO-R
- RNHCOOR – RNH2 CO2 ene
- RNHCOOR – RNHR CO2 ene
E nwere ụzọ atọ isi nke mmebi okpomọkụ nke ihe ndị dabere na polyurethane:
① Ịmepụta isocyanates na polyols mbụ;
② α— Njikọ oxygen dị na ntọala CH2 na-agbaji ma jikọta ya na otu njikọ hydrogen na CH2 nke abụọ iji mepụta amino acid na alkenes. Amino acid na-agbaze ghọọ otu amine mbụ na carbon dioxide:
③ Ụdị 1 nke abụọ amine na carbon dioxide.
Mmebi okpomọkụ nke nhazi carbate:
Aryl NHCO Aryl,~120 ℃;
N-alkyl-NHCO-aryl,~180 ℃;
Aryl NHCO n-alkyl,~200 ℃;
N-alkyl-NHCO-n-alkyl, ~250 ℃.
Nkwụsi ike okpomọkụ nke amino acid esters metụtara ụdị ihe mmalite dịka isocyanates na polyols. Aliphatic isocyanates dị elu karịa aromatic isocyanates, ebe abụba alcohols dị elu karịa aromatic alcohols. Agbanyeghị, akwụkwọ akụkọ na-akọ na okpomọkụ nke aliphatic amino acid esters dị n'etiti 160-180 ℃, na nke aromatic amino acid esters dị n'etiti 180-200 ℃, nke na-ekwekọghị na data dị n'elu. Ihe kpatara ya nwere ike ịbụ njikọ na usoro nnwale ahụ.
N'eziokwu, aliphatic CHDI (1,4-cyclohexane diisocyanate) na HDI (hexamethylene diisocyanate) nwere ike iguzogide okpomọkụ karịa aromatic MDI na TDI a na-ejikarị eme ihe. Karịsịa trans CHDI nke nwere nhazi symmetrical a matala dị ka isocyanate kachasị anabata okpomọkụ. Polyurethane elastomers nke e si na ya kwadebe nwere ike nhazi dị mma, ezigbo iguzogide hydrolysis, okpomọkụ dị nro, obere okpomọkụ mgbanwe iko, obere hysteresis okpomọkụ, na nnukwu iguzogide UV.
Na mgbakwunye na otu amino ester, polyurethane elastomers nwekwara otu ọrụ ndị ọzọ dịka urea formate, biuret, urea, wdg. Otu ndị a nwere ike ịgafe okpomọkụ na oke okpomọkụ:
NHCONCOO – (ụdị urea aliphatic), 85-105 ℃;
- NHCONCOO – (urea na-esi ísì ụtọ), na oke okpomọkụ nke 1-120 ℃;
- NHCONCONH – (aliphatic biuret), na okpomọkụ dị site na 10 ° C ruo 110 ° C;
NHCONCONH – (ihe na-esi ísì ụtọ), 115-125 ℃;
NHCONH – (uria aliphatic), 140-180 ℃;
- NHCONH – (urea na-esi ísì ụtọ), 160-200 ℃;
Mgbanaka Isocyanurate> 270 ℃.
Okpomọkụ nke biuret na urea dabere na ya dị ala karịa nke aminoformate na urea, ebe isocyanurate nwere nkwụsi ike okpomọkụ kachasị mma. N'ime mmepụta nke elastomers, oke isocyanates nwere ike imeghachi omume na aminoformate na urea kpụrụ iji mepụta ụdị formate na biuret jikọtara ọnụ. Ọ bụ ezie na ha nwere ike imeziwanye ihe onwunwe nke elastomers, ha adịghị eguzosi ike nke ukwuu iji kpoo ọkụ.
Iji belata otu ndị na-anaghị ekpo ọkụ dịka biuret na urea formate na elastomers, ọ dị mkpa ịtụle oke ihe ha na-emepụta na usoro mmepụta ha. A ga-eji oke isocyanate eme ihe, a ga-ejikwa ụzọ ndị ọzọ mee ihe dịka o kwere mee iji mepụta mgbanaka isocyanate nke akụkụ n'ime ihe ndị e ji emepụta (karịsịa isocyanates, polyols, na ihe ndọtị agbụ), wee tinye ha n'ime elastomer dịka usoro nkịtị si dị. Nke a aghọọla ụzọ a na-ejikarị eme ihe maka imepụta polyurethane elastomers na-anaghị ekpo ọkụ ma na-anaghị ekpo ọkụ.
03 Mmiri na oxidation okpomọkụ
Elastomers Polyurethane na-adịkarị mfe ire ere okpomọkụ n'akụkụ siri ike ha na mgbanwe kemịkalụ kwekọrọ na akụkụ dị nro ha na okpomọkụ dị elu. Elastomers Polyester anaghị eguzogide mmiri nke ọma ma na-enwe ike ịgbaze hydrolyze n'oge okpomọkụ dị elu. Ndụ ọrụ nke polyester/TDI/diamine nwere ike iru ọnwa 4-5 na okpomọkụ 50 ℃, naanị izu abụọ na okpomọkụ 70 ℃, naanị ụbọchị ole na ole karịa 100 ℃. Njikọ Ester nwere ike ịgbaze ka ọ bụrụ asịd na mmanya ndị kwekọrọ mgbe a na-ekpughe ya na mmiri ọkụ na uzuoku, otu urea na amino ester dị na elastomers nwekwara ike ịgafe mmeghachi omume hydrolysis:
RCOOR H20- → RCOOH HOR
Mmanya Ester
Otu RNHCONHR otu H20- → RXHCOOH H2NR -
Ureamide
Otu RNHCOOR-H20- → RNCOOH HOR -
Amino formate ester Amino formate alcohol
Elastomers ndị e ji polyether mee anaghị enwe ike iguzogide okpomọkụ, ha na elastomers ndị e ji ether mee na-emekwa ka hydrogen dị na atọm carbon dị ngwa ngwa, na-emepụta hydrogen peroxide. Mgbe ha gbasasịrị ma kewaa ya ọzọ, ọ na-emepụta radicals oxide na hydroxyl radicals, nke na-emesịa ghọọ ụdị ma ọ bụ aldehydes.
Polyester dị iche iche enweghị mmetụta dị ukwuu na iguzogide okpomọkụ nke elastomers, ebe polyether dị iche iche nwere mmetụta ụfọdụ. Ma e jiri ya tụnyere TDI-MOCA-PTMEG, TDI-MOCA-PTMEG nwere ọnụego njigide ike nke 44% na 60% n'otu n'otu mgbe ọ dị afọ na 121 ℃ ruo ụbọchị 7, ebe nke ikpeazụ ka mma karịa nke mbụ. Ihe kpatara ya nwere ike ịbụ na molekul PPG nwere agbụ alaka, nke na-adịghị mma maka nhazi nkịtị nke molekul elastic ma na-ebelata iguzogide okpomọkụ nke ahụ elastic. Usoro nkwụsi ike okpomọkụ nke polyethers bụ: PTMEG>PEG>PPG.
Ndị otu ọrụ ndị ọzọ dị na polyurethane elastomers, dị ka urea na carbamate, na-enwetakwa mmeghachi omume oxidation na hydrolysis. Agbanyeghị, otu ether bụ nke a na-eme ka ọ dị mfe oxidation, ebe otu ester bụ nke a na-eme ka ọ dị mfe hydrolyzed. Usoro nke iguzogide antioxidant na hydrolysis ha bụ:
Ọrụ antioxidant: esters> urea> carbamate> ether;
Nguzogide Hydrolysis: ester
Iji melite iguzogide oxidation nke polyether polyurethane na iguzogide hydrolysis nke polyester polyurethane, a na-agbakwụnyekwa ihe mgbakwunye, dị ka ịgbakwunye 1% phenolic antioxidant Irganox1010 na PTMEG polyether elastomer. Ike nrụgide nke elastomer a nwere ike ịbawanye site na ugboro 3-5 ma e jiri ya tụnyere na-enweghị antioxidants (nsonaazụ nnwale mgbe ịka nká na 1500C ruo awa 168). Mana ọ bụghị antioxidant ọ bụla nwere mmetụta na polyurethane elastomers, naanị phenolic 1rganox 1010 na TopanOl051 (phenolic antioxidant, hindered amine light stabilizer, benzotriazole complex) nwere mmetụta dị mkpa, nke mbụ bụkwa nke kacha mma, ikekwe n'ihi na antioxidants phenolic nwere ezigbo ndakọrịta na elastomers. Agbanyeghị, n'ihi ọrụ dị mkpa nke otu phenolic hydroxyl na usoro nkwụsi ike nke antioxidants phenolic, iji zere mmeghachi omume na "ọdịda" nke otu phenolic hydroxyl a nwere otu isocyanate na sistemụ ahụ, oke nke isocyanates na polyols ekwesịghị ịdị oke ibu, a ga-agbakwunyekwa antioxidants na prepolymers na ndị na-agbatị yinye. Ọ bụrụ na etinyere ya n'oge mmepụta nke prepolymers, ọ ga-emetụta mmetụta nkwụsi ike nke ukwuu.
Ihe mgbakwunye e ji egbochi hydrolysis nke polyester polyurethane elastomers bụkarị ihe ndị na-eme ka carbodiimide dị na carboxylic acid nke ester hydrolysis mepụtara na molekul polyurethane elastomer iji mepụta ihe ndị sitere na acyl urea, na-egbochi hydrolysis ọzọ. Mgbakwunye nke carbodiimide na oke nke 2% ruo 5% nwere ike ime ka mmiri polyurethane kwụsie ike ugboro 2-4. Na mgbakwunye, tert butyl catechol, hexamethylenetetramine, azodicarbonamide, wdg nwekwara ụfọdụ mmetụta anti hydrolysis.
04 Njirimara arụmọrụ bụ isi
Polyurethane elastomers bụ ihe ndị a na-ahụkarị dịka multiblock copolymers, ha nwere agbụ molekul nke nwere akụkụ ndị na-agbanwe agbanwe nwere okpomọkụ mgbanwe iko dị ala karịa okpomọkụ ụlọ na akụkụ siri ike nke nwere okpomọkụ mgbanwe iko dị elu karịa okpomọkụ ụlọ. N'ime ha, oligomeric polyols na-etolite akụkụ ndị na-agbanwe agbanwe, ebe diisocyanates na obere molekul chain extenders na-etolite akụkụ siri ike. Nhazi nke akụkụ yinye na-agbanwe agbanwe na nke siri ike na-ekpebi arụmọrụ pụrụ iche ha:
(1) Oke ike nke rọba nkịtị dị n'etiti Shaoer A20-A90, ebe oke ike nke rọba dị ihe dị ka Shaoer A95 Shaoer D100. Elastomers Polyurethane nwere ike iru ala dịka Shaoer A10 ma dị elu dịka Shaoer D85, na-enweghị mkpa enyemaka maka ihe ndozi;
(2) Ike na nrịgharị dị elu ka nwere ike ịnọgide na-enwe ike n'ime ọtụtụ ụdị siri ike;
(3) Nguzogide iyi dị mma, nke okpukpu abụọ ruo iri karịa nke roba eke;
(4) Ọ dị mma iguzogide mmiri, mmanụ, na kemịkalụ;
(5) Nguzogide mmetụta dị elu, ike ọgwụgwụ, na iguzogide mkpọtụ, nke dabara adaba maka ngwa mgbagọ ugboro ugboro;
(6) Ezigbo iguzogide obere okpomọkụ, yana obere mgbawa okpomọkụ dị n'okpuru -30 ℃ ma ọ bụ -70 ℃;
(7) O nwere arụmọrụ mkpuchi dị mma, n'ihi obere ike okpomọkụ ya, ọ nwere mmetụta mkpuchi ka mma ma e jiri ya tụnyere roba na plastik;
(8) Ezigbo nkwekọ bio na ihe ndị na-egbochi ọbara ọgbụgba;
(9) Ọ dị mma maka mkpuchi eletriki, iguzogide ebu, na nkwụsi ike UV.
Enwere ike iji otu usoro dị ka roba nkịtị mepụta polyurethane elastomers, dịka ime ka ọ dị ọcha, ịgwakọta ihe, na ịgbawa ihe. Enwere ike ịkpụzi ha n'ụdị roba mmiri site na ịwụsa ihe, ịkpụ ihe n'ime centrifugal, ma ọ bụ ịgbasa ihe. Enwere ike ime ha ka ha bụrụ ihe granular ma mepụta ha site na iji ọgwụ ntụtụ, extrusion, rolling, flushing molding, na usoro ndị ọzọ. N'ụzọ dị otu a, ọ bụghị naanị na ọ na-eme ka arụmọrụ ọrụ ka mma, kamakwa ọ na-eme ka izi ezi na ọdịdị nke ngwaahịa ahụ ka mma.
Oge ozi: Disemba-05-2023