Into ebizwai-polyurethanesisishunqulelo se-polyurethane, esakhiwe yi-reaction ye-polyisocyanates kunye ne-polyols, kwaye iqulethe amaqela amaninzi aphindaphindiweyo amino ester (- NH-CO-O -) kwikhonkco le-molecular.Kwiintsika ze-polyurethane ezenziweyo ngokwenene, ukongeza kwiqela le-amino ester, kukho amaqela afana ne-urea kunye ne-biuret.Iipolyols zezeamolekyuli ze-long-chain kunye namaqela e-hydroxyl ekugqibeleni, abizwa ngokuba "ngamacandelo e-soft chain", ngelixa i-polyisocyanates ibizwa ngokuba "ngamacandelo anzima".
Phakathi kwee-resin ze-polyurethane ezenziwe ngamacandelo athambileyo kwaye aqinile, ipesenti encinci kuphela i-amino acid esters, ngoko ke kungenakufaneleka ukubiza ngokuba yi-polyurethane.Ngengqiqo ebanzi, i-polyurethane i-additive ye-isocyanate.
Iindidi ezahlukeneyo ze-isocyanates zisabela kunye neekhompawundi ze-polyhydroxy ukuvelisa izakhiwo ezahlukahlukeneyo ze-polyurethane, ngaloo ndlela zifumana izinto ze-polymer ezineempawu ezahlukeneyo, njengeeplastiki, irabha, i-coatings, i-fibers, i-adhesives, njl.
Irabha ye-polyurethane yeyohlobo olukhethekileyo lwerabha, eyenziwa ngokuphendula i-polyether okanye i-polyester ene-isocyanate.Kukho iintlobo ezininzi ngenxa yeentlobo ezahlukeneyo zemathiriyeli ekrwada, iimeko zokusabela, kunye neendlela zokudibanisa.Ukususela kumbono wesakhiwo sekhemikhali, kukho i-polyester kunye ne-polyether iintlobo, kwaye ukusuka kwindlela yokucubungula, kukho iintlobo ezintathu: uhlobo lokuxuba, uhlobo lokuphosa, kunye nohlobo lwe-thermoplastic.
Irabha ye-Synthetic ye-polyurethane idla ngokudityaniswa ngokuphendula i-polyester yomgama okanye i-polyether ene-diisocyanate ukuze yenze i-prepolymer yobunzima bemolekyuli ephantsi, ethi emva koko iphantsi kolwandiso lolwandiso lwekhonkco ukuvelisa i-polymer yobunzima bemolekyuli ephezulu.Emva koko, ii-agent ezinqamlezileyo ezifanelekileyo zongezwa kwaye zifudunyezwe ukunyanga, zibe yirabha ehlanjululweyo.Le ndlela ibizwa ngokuba yi-prepolymerization okanye indlela yamanyathelo amabini.
Kwakhona kunokwenzeka ukusebenzisa indlela yesinyathelo-nye - ukuxuba ngokuthe ngqo i-polyester yomgca okanye i-polyether ene-disocyanates, i-chain extenders, kunye ne-crosslinking agents ukuqalisa ukusabela kunye nokuvelisa irabha ye-polyurethane.
I-A-segment kwiimolekyuli ze-TPU yenza ukuba i-macromolecular chains ibe lula ukujikeleza, inika irabha ye-polyurethane ene-elasticity elungileyo, ukunciphisa indawo yokuthambisa kunye nenqanaba lesibini lenguqu yepolymer, kunye nokunciphisa ubunzima bayo kunye namandla omatshini.I-B-segment iya kubopha ukujikeleza kwamaketanga e-macromolecular, okubangela ukuba i-softening point kunye ne-second transition point ye-polymer inyuke, okubangelwa ukwanda kobunzima kunye namandla omatshini, kunye nokuncipha kwe-elasticity.Ngokulungelelanisa umlinganiselo we-molar phakathi kwe-A kunye ne-B, ii-TPU ezineempawu ezahlukeneyo zomatshini zinokuveliswa.Isakhiwo sokudibanisa i-TPU akufunekanga siqwalasele i-primary cross-linking, kodwa kunye ne-second cross-linking eyenziwe ngamabhondi e-hydrogen phakathi kwama-molecule.Ibhondi ephambili yokudibanisa i-polyurethane ihluke kwisakhiwo se-vulcanization ye-rubber ye-hydroxyl.Iqela layo le-amino ester, iqela le-biuret, iqela le-urea ye-formate kunye namanye amaqela asebenzayo ahlelwe kwinqanaba eliqhelekileyo kunye nesithuba sekhonkco eliqinileyo, elikhokelela kwisakhiwo esiqhelekileyo sothungelwano lwerabha, enokumelana nokunxiba okugqwesileyo kunye nezinye iimpawu ezigqwesileyo.Okwesibini, ngenxa yobukho bamaqela amaninzi asebenza ngokudibeneyo afana ne-urea okanye amaqela e-carbamate kwirabha ye-polyurethane, iibhondi ze-hydrogen ezenziwe phakathi kwamatyathanga eemolekyuli zinamandla amakhulu, kwaye i-second crosslinking bonds eyenziwe ngamabhondi e-hydrogen nawo anempembelelo enkulu kwiipropati irabha yepolyurethane.Ukudityaniswa komnqamlezo okwesibini kwenza irabha ye-polyurethane ibe neempawu ze-thermosetting elastomers kwelinye icala, kwaye kwelinye icala, oku kudityaniswa komnqamlezo akuqhagamshelwanga ngokwenene, kuyenza ibe yinto edibanisayo.Imeko yokudibanisa i-cross-link ixhomekeke kwiqondo lokushisa.Njengoko iqondo lobushushu lisanda, le cross-linking iyancipha ngokuthe ngcembe kwaye iphele.I-polymer ine-fluidity ethile kwaye inokuthi ifakwe phantsi kwe-thermoplastic processing.Xa amaqondo obushushu ehla, le cross-linking ngokuthe ngcembe ibuyela kwaye kwakheka kwakhona.Ukongezwa kwexabiso elincinci lokuzalisa kwandisa umgama phakathi kweeamolekyu, kunciphisa amandla okwenza i-hydrogen bond phakathi kwama-molecule, kwaye kukhokelela ekunciphiseni okubukhali kwamandla.Uphando lubonise ukuba umyalelo wokuzinza kwamaqela ahlukeneyo asebenzayo kwirabha ye-polyurethane ukusuka phezulu ukuya ephantsi: i-ester, i-ether, i-urea, i-carbamate, kunye ne-biuret.Ngexesha lenkqubo yokuguga yerabha ye-polyurethane, isinyathelo sokuqala kukuqhawula amabhondi okudibanisa phakathi kwe-biuret kunye ne-urea, kulandelwa ukuphulwa kwe-carbamate kunye ne-urea bonds, oko kukuthi, ukuphulwa kwekhonkco.
01 Ukuthamba
I-polyurethane elastomers, njengezinto ezininzi ze-polymer, zithambisa kumaqondo aphezulu kunye nokuguquka ukusuka kwi-elastic state ukuya kwi-viscous flow flow, okukhokelela ekunciphiseni ngokukhawuleza kwamandla omatshini.Ngokwembono yekhemikhali, ubushushu obuthambileyo be-elasticity ubukhulu becala buxhomekeke kwizinto ezifana nokwakheka kweekhemikhali, ubunzima bemolekyuli, kunye nokuxinana kokudibanisa.
Ngokuqhelekileyo, ukwandisa ubunzima be-molecular weight, ukwandisa ukuqina kwecandelo elinzima (njengokungenisa i-benzene ring kwi-molecule) kunye nomxholo wecandelo elinzima, kunye nokunyusa ukuxinana kwe-crosslinking konke kunenzuzo ekunyuseni ukufudumala kweqondo lokushisa.Kwii-elastomers ze-thermoplastic, ulwakhiwo lwe-molekyuli ubukhulu becala lumgca, kwaye ubushushu obuthambileyo be-elastomer buyanda xa ubunzima bemolekyuli bonyuka.
Kwii-elastomers ze-polyurethane ezinqamlezileyo, ukuxinana kwe-crosslink kunempembelelo enkulu kunobunzima bemolekyuli.Ke ngoko, xa kusenziwa ii-elastomers, ukonyusa ukusebenza kwee-isocyanates okanye ii-polyols kunokwenza inethiwekhi ezinzileyo yekhemikhali edibanisa i-cross-linking structure kwezinye iimolekyuli ezinwebekayo, okanye zisebenzisa i-isocyanate ratios ezigqithisileyo ukwenza i-isocyanate ezinzileyo yokudibanisa umnqamlezo kumzimba we-elastic. indlela enamandla yokuphucula ukumelana nobushushu, ukuxhathisa kwe-solvent, kunye namandla omatshini we-elastomer.
Xa i-PPDI (p-phenyldiisocyanate) isetyenziswa njengento ekrwada, ngenxa yokunxibelelana ngokuthe ngqo kwamaqela amabini e-isocyanate kwiringi ye-benzene, icandelo eliqinileyo elibunjiweyo linomxholo ophezulu we-benzene, ophucula ukuqina kwecandelo eliqinileyo kwaye ngaloo ndlela liphucula. ukumelana nobushushu kwe-elastomer.
Ukusuka kumbono womzimba, ubushushu obuthambileyo be-elastomers buxhomekeke kwiqondo lokuhlukana kwe-microphase.Ngokweengxelo, iqondo lokushisa elithambileyo le-elastomers elingenalo ukwahlukana kwe-microphase liphantsi kakhulu, kunye neqondo lokushisa elimalunga ne-70 ℃ kuphela, ngelixa i-elastomers edlula ukuhlukana kwe-microphase inokufikelela kwi-130-150 ℃.Ke ngoko, ukonyusa inqanaba lokuhlukana kwe-microphase kwii-elastomers yenye yeendlela ezisebenzayo zokuphucula ukuxhathisa ubushushu.
Iqondo lokuhlukana kwe-microphase ye-elastomers inokuphuculwa ngokutshintsha ukusabalalisa ubunzima bemolekyuli yamacandelo ekhonkco kunye nomxholo wamacandelo ekhonkco eliqinileyo, ngaloo ndlela kwandisa ukuxhathisa ubushushu.Uninzi lwabaphandi bakholelwa ukuba isizathu sokuhlukana kwe-microphase kwi-polyurethane kukungahambelani kwe-thermodynamic phakathi kwamacandelo athambileyo kunye anzima.Uhlobo lwe-chain extender, icandelo elinzima kunye nomxholo walo, uhlobo lwecandelo elithambileyo, kunye ne-hydrogen bonding zonke zinempembelelo enkulu kuyo.
Xa kuthelekiswa nezandisi ze-diol chain, izandisi ze-diamine chain ezifana ne-MOCA (3,3-dichloro-4,4-diaminodiphenylmethane) kunye ne-DCB (3,3-dichloro-biphenylenediamine) zenza amaqela amaninzi e-amino ester kwi-elastomers, kunye neebhondi ze-hydrogen ezingaphezulu yenziwe phakathi kwamacandelo anzima, ukwandisa ukusebenzisana phakathi kwamacandelo anzima kunye nokuphucula iqondo lokuhlukana kwe-microphase kwi-elastomers;Izandiso zekhonkco eliqholiweyo elifana ne-p, i-p-dihydroquinone, kunye ne-hydroquinone ziluncedo kwi-normalization kunye nokupakishwa okuqinileyo kwamacandelo anzima, ngaloo ndlela kuphuculwa ukwahlulwa kwe-microphase yeemveliso.
Amacandelo e-amino ester aqulunqwe yi-aliphatic isocyanates anokuhambelana kakuhle kunye namacandelo athambileyo, okubangela ukuba amacandelo anzima ngakumbi anyibilike kumacandelo athambileyo, ukunciphisa iqondo lokuhlukana kwe-microphase.Amacandelo e-amino ester enziwe ngama-isocyanates anuka kamnandi awahambelani kakuhle namacandelo athambileyo, ngelixa iqondo lokuhlukana kwe-microphase liphezulu.I-Polyolefin i-polyurethane inokwakheka kokwahlukana kwe-microphase ephantse iphelele ngenxa yokuba icandelo elithambileyo alizenzi iibhondi ze-hydrogen kwaye iibhondi ze-hydrogen zinokwenzeka kuphela kwicandelo elilukhuni.
Impembelelo ye-hydrogen bonding kwindawo yokuthambisa ye-elastomers nayo ibalulekile.Nangona i-polyethers kunye ne-carbonyls kwi-soft segment ingenza inani elikhulu le-hydrogen bond kunye ne-NH kwicandelo elinzima, likwanyusa ubushushu obuthambileyo be-elastomers.Kuye kwaqinisekiswa ukuba iibhondi ze-hydrogen zisagcina i-40% kwi-200 ℃.
02 Ukubola kobushushu
Amaqela e-amino ester afumana oku kubola kulandelayo kumaqondo obushushu aphezulu:
- RNHCOOR – RNC0 HO-R
- RNHCOOR – RNH2 CO2 ene
- RNHCOOR – RNHR CO2 ene
Kukho iindlela ezintathu eziphambili zokubola kwe-thermal yezixhobo ezisekelwe kwi-polyurethane:
① Ukwenza ii-isocyanates zoqobo kunye neepolyols;
② α— Ibhondi ye-oksijini kwisiseko se-CH2 iyaphuka kwaye idibanise nebhondi enye ye-hydrogen kwi-CH2 yesibini ukwenza i-amino acids kunye ne-alkenes.Ii-amino acids zibola zibe yi-amine yokuqala kunye ne-carbon dioxide:
③ Ifom yoku-1 ye-amine yesibini kunye ne-carbon dioxide.
Ukubola kwe-thermal yesakhiwo se-carbamate:
Aryl NHCO Aryl, ~ 120 ℃;
N-alkyl-NHCO-aryl, ~ 180 ℃;
Aryl NHCO n-alkyl, ~ 200 ℃;
N-alkyl-NHCO-n-alkyl, ~ 250 ℃.
Ukuzinza kwe-thermal ye-amino acid esters ihambelana neentlobo zezixhobo zokuqala ezifana ne-isocyanates kunye ne-polyols.I-aliphatic isocyanates iphezulu kune-isocyanates enevumba elimnandi, ngelixa ii-alcohols ezinamafutha ziphezulu kune-alcohols enuka kamnandi.Nangona kunjalo, ingxelo yoncwadi inika ingxelo yokuba iqondo lobushushu lokubola kwe-aliphatic amino acid esters liphakathi kwe-160-180 ℃, kunye ne-amino acid ester enevumba elimnandi liphakathi kwe-180-200 ℃, engahambelaniyo nale datha ingasentla.Isizathu sinokunxulumana nendlela yokuvavanya.
Enyanisweni, i-aliphatic CHDI (i-1,4-cyclohexane diisocyanate) kunye ne-HDI (i-hexamethylene diisocyanate) inokumelana nobushushu obungcono kune-MDI kunye ne-TDI esetyenziswa ngokuqhelekileyo.Ngokukodwa i-trans CHDI ene-symmetrical structure iye yaqatshelwa njengeyona isocyanate ekwazi ukumelana nobushushu.I-polyurethane elastomers ezilungiselelwe ukusuka kuyo zinokusetyenzwa kakuhle, ukumelana ne-hydrolysis okugqwesileyo, ubushushu obuphezulu bokuthambisa, ubushushu obuphantsi beglasi, i-hysteresis ephantsi ye-thermal, kunye nokumelana okuphezulu kwe-UV.
Ukongeza kwiqela le-amino ester, i-polyurethane elastomers inamanye amaqela asebenzayo afana ne-urea formate, i-biuret, i-urea, njl.
NHCONCOO – (aliphatic urea formate), 85-105 ℃;
- NHCONCOO – (aromatic urea formate), kwiqondo lobushushu 1-120 ℃;
- I-NHCONCONH - (i-aliphatic biuret), kwiqondo lokushisa ukusuka kwi-10 ° C ukuya kwi-110 ° C;
I-NHCONCONH – (i-aromatic biuret), 115-125 ℃;
NHCONH – (aliphatic urea), 140-180 ℃;
- NHCONH – (urea enuka kamnandi), 160-200 ℃;
Umsesane we-Isocyanurate>270 ℃.
Iqondo lokushisa lokubola kwe-biuret kunye ne-urea esekelwe kwi-formate iphantsi kakhulu kune-aminoformate kunye ne-urea, ngelixa i-isocyanurate inozinzo olungcono lwe-thermal.Kwimveliso yee-elastomers, ii-isocyanates ezigqithisileyo zinokuphinda ziqhubele phambili nge-aminoformate eyenziweyo kunye ne-urea ukuze zenze i-urea esekwe kwifomati kunye ne-biuret edibeneyo edibeneyo.Nangona zinokuphucula iipropathi zoomatshini ze-elastomers, azinzanga ngokugqithisileyo ekutshiseni.
Ukunciphisa amaqela e-thermal angazinzanga njenge-biuret kunye ne-urea formate kwi-elastomers, kuyimfuneko ukuqwalasela umlinganiselo wabo wezinto eziluhlaza kunye nenkqubo yokuvelisa.Kufuneka kusetyenziswe umlinganiselo ogqithisileyo we-isocyanate, kwaye ezinye iindlela kufuneka zisetyenziswe kangangoko kunokwenzeka ukwenza kuqala imisesane ye-isocyanate engaphelelanga kwimathiriyeli ekrwada (ingakumbi i-isocyanates, i-polyols, kunye ne-chain extender), kwaye emva koko waziswe kwi-elastomer ngokweenkqubo eziqhelekileyo.Le iye yaba yeyona ndlela isetyenziswa kakhulu ekuveliseni i-polyurethane elastomers ekwaziyo ukumelana nobushushu kunye nelangatye.
03 I-Hydrolysis kunye ne-thermal oxidation
I-polyurethane elastomers iyakwazi ukubola kwi-thermal kumacandelo abo anzima kunye nokutshintsha kweekhemikhali ezihambelanayo kumacandelo azo athambileyo kumaqondo aphezulu.I-polyester elastomers azikwazi ukumelana namanzi kunye notyekelo oluqatha lokusebenzisa i-hydrolyze kumaqondo obushushu aphezulu.Ubomi benkonzo ye-polyester/TDI/diamine inokufikelela kwiinyanga ezi-4-5 kwi-50 ℃, iiveki ezimbini kuphela kwi-70 ℃, kunye neentsuku ezimbalwa kuphela ngaphezulu kwe-100 ℃.Iibhondi ze-Ester zinokubola zibe ziiasidi ezihambelanayo kunye neealkoholi xa zisesichengeni samanzi ashushu kunye nomphunga, kwaye amaqela e-urea kunye ne-amino ester kwi-elastomers nawo anokusabela kwi-hydrolysis:
RCOOR H20- → RCOOH HOR
Ester utywala
Enye i-RNHCONHR enye H20- → RXHCOOH H2NR -
Ureamide
Enye RNHCOOR-H20- → RNCOOH HOR -
Amino formate ester Amino formate utywala
I-polyether esekelwe kwi-elastomers inozinzo olubi lwe-thermal oxidation, kunye ne-ether esekelwe kwi-elastomers α- I-hydrogen kwi-athomu ye-carbon i-oxidized ngokulula, yenze i-hydrogen peroxide.Emva kokubola ngakumbi kunye nokuqhekeka, ivelisa i-oxide radicals kunye ne-hydroxyl radicals, ethi ekugqibeleni ibole ibe yifomathi okanye i-aldehydes.
Iipolyester ezahlukeneyo zinempembelelo encinci ekuxhathiseni ubushushu be-elastomers, ngelixa iipolyester ezahlukeneyo zinempembelelo ethile.Xa kuthelekiswa ne-TDI-MOCA-PTMEG, i-TDI-MOCA-PTMEG inereyithi yokugcina amandla e-tensile angama-44% kunye nama-60% ngokulandelelanayo xa ineminyaka eyi-121 ℃ iintsuku ezisi-7, kwaye le yokugqibela ingcono kakhulu kuneyangaphambili.Isizathu sinokuthi iamolekyu ze-PPG zinamatyathanga e-branched, angahambelani nokulungelelaniswa okuqhelekileyo kweeamolekyuli ze-elastic kunye nokunciphisa ukuxhathisa ukushisa komzimba.I-thermal stability order yeepolyethers yile: PTMEG>PEG>PPG.
Amanye amaqela asebenzayo kwii-polyurethane elastomers, ezifana ne-urea kunye ne-carbamate, nazo zingena kwi-oxidation kunye ne-hydrolysis reactions.Nangona kunjalo, iqela le-ether lelona li-oxidized ngokulula, ngelixa iqela le-ester lelona li-hydrolyzed ngokulula.Umyalelo wokumelana ne-antioxidant kunye ne-hydrolysis yile:
Umsebenzi we-Antioxidant: esters>urea>carbamate>ether;
Ukumelana ne-Hydrolysis: i-ester
Ukuphucula ukuxhathisa kwe-oxidation ye-polyether polyurethane kunye nokumelana ne-hydrolysis ye-polyester polyurethane, izongezo zongezwa, njengokongeza i-1% ye-phenolic antioxidant Irganox1010 kwi-PTMEG i-polyether elastomer.Amandla e-tensile yale elastomer anganyuswa ngamaxesha angama-3-5 xa kuthelekiswa ngaphandle kwe-antioxidants (iziphumo zovavanyo emva kokuguga kwi-1500C kwiiyure ze-168).Kodwa ayizizo zonke i-antioxidant ezinefuthe kwi-polyurethane elastomers, kuphela i-phenolic 1rganox 1010 kunye ne-TopanOl051 (i-phenolic antioxidant, i-hindered amine light stabilizer, i-benzotriazole complex) ineempembelelo ezibalulekileyo, kwaye eyona nto yangaphambili yeyona nto ingcono, mhlawumbi ngenxa yokuba i-phenolic antioxidants inokuhambelana kakuhle ne-elastomers.Nangona kunjalo, ngenxa yendima ebalulekileyo yamaqela e-phenolic hydroxyl kwindlela yokuzinzisa ye-phenolic antioxidants, ukuze uthintele ukuphendula kunye "nokusilela" kweli qela le-phenolic hydroxyl elinamaqela e-isocyanate kwinkqubo, umlinganiselo we-isocyanates kwii-polyols awufanele ube. inkulu kakhulu, kwaye i-antioxidants kufuneka yongezwe kwii-prepolymers kunye ne-chain extenders.Ukuba yongezwa ngexesha lokuveliswa kwe-prepolymers, iya kuchaphazela kakhulu umphumo wokuzinza.
Izongezo ezisetyenziselwa ukuthintela i-hydrolysis ye-polyester polyurethane elastomers ubukhulu becala ziikhompawundi ze-carbodiimide, ezithi zisebenze kunye ne-carboxylic acids eveliswa yi-ester hydrolysis kwiimolekyuli ze-polyurethane elastomer ukuvelisa i-acyl urea derivatives, ukuthintela ukuqhubekeka kwe-hydrolysis.Ukongezwa kwe-carbodiimide kwiqhekeza elikhulu le-2% ukuya kwi-5% kunokunyusa ukuzinza kwamanzi e-polyurethane ngamaxesha angama-2-4.Ukongeza, i-tert butyl catechol, i-hexamethylenetetramine, i-azodicarbonamide, njl.
04 Iimpawu eziphambili zokusebenza
I-polyurethane elastomers ziqhelekileyo ii-block copolymers, ezinamatyathanga emolekyuli akhiwe ngamacandelo aguqukayo aneqondo lobushushu leglasi elingaphantsi kweqondo lobushushu begumbi kunye namacandelo aqinileyo anobushushu beglasi obungaphezulu kunobushushu begumbi.Phakathi kwazo, iipolyoli ze-oligomeric zenza amacandelo aguquguqukayo, ngelixa i-disocyanates kunye ne-molekyuli encinci yezandiso zenza amacandelo aqinileyo.Ulwakhiwo oludityanisiweyo lwamacandelo athambileyo kunye noluqilima lumisela ukusebenza kwawo okwahlukileyo:
(1) Ubunzima berabha eqhelekileyo ngokuqhelekileyo phakathi kwe-Shaoer A20-A90, ngelixa ubunzima beplastiki bumalunga neShaoer A95 Shaoer D100.I-polyurethane elastomers inokufikelela ezantsi njenge-Shaoer A10 kwaye iphakame njenge-Shaoer D85, ngaphandle kwesidingo soncedo lokuzalisa;
(2) Amandla aphezulu kunye nokunwebeka kusenokugcinwa ngaphakathi koluhlu olubanzi lobulukhuni;
(3) Ukuxhathisa okugqwesileyo kokunxiba, amaxesha angama-2-10 erabha yendalo;
(4) Ukuxhathisa okugqwesileyo kumanzi, ioli, kunye nemichiza;
(5) Ukuxhathisa impembelelo ephezulu, ukuxhathisa ukukhathala, kunye nokuxhatshazwa kwe-vibration, efanelekileyo kwizicelo zokugoba eziphezulu;
(6) Ukumelana kakuhle nobushushu obuphantsi, kunye nobushushu obuphantsi brittleness ngaphantsi -30 ℃ okanye -70 ℃;
7
(8) I-biocompatibility efanelekileyo kunye neempawu ze-anticoagulant;
(9) Ukugquma kombane okugqwesileyo, ukumelana nokungunda, kunye nokuzinza kwe-UV.
I-polyurethane elastomers inokusekwa kusetyenziswa iinkqubo ezifanayo njengerabha eqhelekileyo, efana neplastiki, ukuxuba, kunye ne-vulcanization.Zisenokubunjwa ngendlela yerabha engamanzi ngokugalela, ukubumba i-centrifugal, okanye ukutshiza.Zisenokwenziwa kwakhona zibe yimathiriyeli yegranular kwaye zenziwe kusetyenziswa inaliti, i-extrusion, i-rolling, i-blow molding, kunye nezinye iinkqubo.Ngale ndlela, ayiphuculi nje ukusebenza kakuhle, kodwa ikwaphucula ukuchaneka komgangatho kunye nenkangeleko yemveliso.
Ixesha lokuposa: Dec-05-2023