Ngokungafani ne-thermoplastics, ama-elastomer ajwayele ukusetshenziswa emazingeni okushisa anhlobonhlobo futhi ngaphezu kwezinga lokushisa lokushintsha kwengilazi (Tg). Izinzuzo zama-elastomers ngaphezu kwe-thermoplastics yikhono lawo lokululama cishe ngokuphelele esimweni esiqinile (ukunwebeka okuphezulu), kanye nokunwebeka kwawo okujwayelekile, ubulukhuni obuphansi kanye nezakhiwo eziphansi ze-modulus. Lapho ama-elastomers esetshenziswa ngaphansi kwezinga lokushisa legumbi, abonisa ukwanda kokuqina, ukwanda kwe-modulus, nokuncipha kokunwebeka. Uma ama-elastomer esetshenziswa ngaphansi kwezinga lokushisa legumbi, kunokuthambekela kokuqina kokuqina, i-modulus ukwanda, ukunwebeka ukuze kwehle (i-tensile ephansi) nokuminyanisa kusethelwe ukwanda. Kuye ngenkinga nge-elastomer, izenzakalo ezimbili zingenzeka ngesikhathi esisodwa - ukuqina kwengilazi kanye ne-crystallization eyingxenye - i-CR, i-EPDM, i-NR izibonelo ezithile zama-elastomers abonisa i-crystallization.
1. Uhlolojikelele lokuhlolwa kwezinga lokushisa eliphansi
I-Brittleness, i-compress deformation unomphela, ukuhlehlisa, ukuqina kanye nokuqina kwe-cryogenic kusetshenziswe iminyaka eminingi ukuze kubonakale izakhiwo ze-polymer emazingeni okushisa aphansi. Ukuphumula kwengcindezi ecindezelayo kusha futhi kugxile ekunqumeni amandla okuvalwa kwento ethile esikhathini esithile ngaphansi kwezimo ezihlukahlukene zemvelo.
2. I-Brittleness Temperature
I-ASTM D 2137 ichaza izinga lokushisa le-brittleness njengezinga lokushisa eliphansi kakhulu lapho irabha ethintekile ingeke ibonise ukuphuka noma ukuphuka ngaphansi kwezimo ezithile zomthelela. Izibonelo zenjoloba ezinhlanu zomumo onqunywe kusengaphambili ziyalungiswa, zibekwe ekamelweni noma endaweni ewuketshezi, ngaphansi kwezinga lokushisa elimisiwe elingu-3±0.5min, bese linikezwa isivinini somthelela esingu-2.0±0.2m/s. Ama-specimens asusiwe futhi angaphansi kokuhlolwa komthelela noma ukuphuka. Isifanekiso siyasuswa futhi sihlolelwe umthelela noma ukuphuka, konke ngaphandle kokulimala. Ukuhlolwa kwaphindwa kwaze kwafika emazingeni okushisa okonakala - izinga lokushisa eliphansi kakhulu lapho kungatholwanga ukuphuka kwakusondele kakhulu ku-1°C.
3. Isethi Yokucindezelwa Kwezinga Eliphansi kanye Nokuqina Kwezinga Lokushisa Eliphansi
Inqubo yokuhlola yesethi yokuminyanisa kwezinga lokushisa eliphansi iseduze kakhulu naleyo yesethi yokuminyanisa okujwayelekile, ngaphandle kokuthi izinga lokushisa lilawulwa indlela ethile yamandla, njengeqhwa elomile, i-nitrogen ewuketshezi, noma izindlela zemishini, futhi inani lingaphakathi kuka-± 1°C wezinga lokushisa elisethiwe. Ngemva kokululama endaweni, isifanekiso siphinde sibekwe ezingeni lokushisa eliphansi esethiwe futhi sibunjwe sibe ububanzi obungu-29 mm nogqinsi luka-12.5 mm. Isethi yokucindezela kwezinga lokushisa eliphansi iyindlela engaqondile yokuvala izinhlelo zokusebenza zenkomponi okukhulunywa ngayo. Ukuphumula kokucindezeleka okucindezelayo kuyindlela eqondile futhi kuzoxoxwa ngayo kamuva. Ukuqina kwezinga lokushisa eliphansi nakho kuvame ukunqunywa kusetshenziswa isifanekiso sesethi yokucindezela (29mm x 12.5mm), kodwa sihlolwe kabusha ekulawuleni izinga lokushisa eliphansi, okufana nalokhu kwesethi yokuminyanisa, bese futhi kumazinga okushisa afanayo nezinga lawo lokushisa elimisiwe. Ukuqina nokushisa okuphansi kwesethi yokucindezela kuthinteka ngokuqondile ngokupholisa, kodwa futhi nokuthambekela kwe-polymer ukucwebezela, ngezinga le-crystallization lincike ekushiseni, isb, i-CR icwebezela ngokushesha cishe -10 ° C, bese yehla emazingeni okushisa aphansi, ikakhulukazi ngenxa yokunganyakazi kwezingxenye ze-polymer chain (i-molecular chain frize).
4. Gehman Low Temperature Ukuqina
I-ASTM D 1053 ichaza indlela yokuqina kwezinga lokushisa eliphansi ngale ndlela elandelayo: uchungechunge lwezibonelo ze-polymer ezinwebekayo zixhunywe ngokuqinile ocingweni olune-torsional constant eyaziwayo, kanti enye ingxenye yocingo ixhunywe ekhanda le-torsion elikwazi ukuvumela ucingo ukuba lusonte. Ama-specimens acwiliswa endaweni yokudlulisa ukushisa ezingeni lokushisa elithile elingaphansi kokujwayelekile, ngaleso sikhathi ikhanda le-torsion lisonteka ngo-180 °, bese ama-specimens esontwa inani (elingaphansi kuka-180 °) elincike ekuphambeni kokuguquguquka nokuqina kwesifanekiso. Bese usebenzisa inani le-goniometer ukuze unqume inani le-specimen twist, i-engeli ye-twist kanye nokuqina kwento yerabha. Izinga lokushisa lesistimu liyenyuka kancane kancane kuleli phuzu, futhi isiqephu se-angle ye-twist ngokumelene nokushisa sitholakala. Amazinga okushisa lapho i-modulus ifinyelela ku-T2, T10, ne-T100 ngokuvamile aqoshwa njengalingana nenani le-modulus ekamelweni lokushisa.
5. Ukuhoxiswa Kwezinga Lokushisa Eliphansi (Ukuhlolwa kwe-TR)
Ukuhlolwa kwe-TR kusetshenziselwa ukuhlola ikhono lesifanekiso esimweni sokushuba lapho ukuguquguquka okungapheli okucindezelayo kanye nokuphumula kwengcindezi ecindezelayo okunqunywe ingcindezi yokucindezela kusetshenziswa ukunquma imiphumela ephansi yezinga lokushisa. Njengoba kuveziwe ngaphambili, ama-polymer amaningi afana ne-NR ne-PVC azocwebezela emazingeni okushisa aphansi, kodwa ukwelula kungase futhi kucwebezele, okuholela ezicini ezengeziwe lapho ubheka izakhiwo zokushisa eziphansi. Kuzinhlelo zokusebenza zokuhlola ezifana nokumiswa kwe-exhaust, i-TR ngaphansi kwe-tension ifaneleka kakhulu futhi isetshenziswa njalo. Kulokhu kuhlolwa, isifanekiso sinwetshwa (ngokuvamile ngo-50% noma 100%) futhi siqandiswe esimweni esibude. Isifanekiso siyakhululwa, ngaleso sikhathi izinga lokushisa liphakanyiswa ngezinga elinqunyiwe ukuze kulinganiswe ukubuyiswa kwesifanekiso, ubude bokuncipha buyalinganiswa futhi ukwelulwa kuyarekhodwa. Amazinga okushisa lapho isifanekiso sincipha ngo-10%, 30%, 50%, no-70% ngokuvamile siphawulwa ngokuthi TR10, TR30, TR50, kanye TR70. I-TR10 ihlobene nezinga lokushisa elibi; I-TR70 ihlobene nokuguqulwa unomphela kwesifanekiso ekucindezelweni kwezinga lokushisa eliphansi; futhi umehluko phakathi kwe-TR10 ne-TR70 isetshenziselwa ukukala ukucwebezela kwesifanekiso (uma umehluko omkhulu, ukuthambekela kokucwebezela kukhulu).
6 . I-Low Temperature Compressive Stress Relaxation (CSR)
Ukuhlolwa kwe-CSR kungasetshenziswa ukwenza izibikezelo mayelana nokusebenza nempilo yezinto zokuvala. Lapho inhlanganisela ye-elastomeric inikezwa ukuguqulwa okuqhubekayo, amandla ahlangene ayakhiwa, futhi ikhono lempahla yokugcina la mandla ngaphakathi kohla oluthile lwezemvelo lilinganisa ikhono layo lokuvala. Zombili izindlela ezingokomzimba nezamakhemikhali zifaka isandla ekuphumuleni kwengcindezi, ngokusekelwe esikhathini namazinga okushisa, into eyodwa izobusa, ukuphumula ngokomzimba kubonakala emazingeni okushisa aphansi, ngokushesha ngemva kokucindezeleka okunikeziwe, okuholela ekuhleleni kabusha kwamaketanga kanye nezinguquko endaweni yokugcwalisa irabha kanye ne-filler-filler, futhi ukuphumula kwesistimu yokususa ukucindezeleka kuyabuyiselwa emuva. Emazingeni okushisa aphezulu, ukwakheka kwamakhemikhali kunquma izinga lokuphumula, lapho izinqubo zomzimba sezivele zizincane futhi ukukhululeka kwamakhemikhali kungenakuhlehliswa, okuholela ekuqhekekeni kweketango kanye nokusabela okuxhumanisayo. Ukuhamba ngebhayisikili okunezinga lokushisa noma ukunyuka kwezinga lokushisa okungazelelwe kungaba nomthelela ekuphumuleni kwengcindezi kuma-elastomer. Ngesikhathi sokuhlolwa kwe-CSR, isampula yokuhlola ifakwa
Phakathi nokuhlolwa kwe-CSR, ukukhululeka kwengcindezi kuyakhuphuka lapho isifanekiso sokuhlola singaphansi kwamazinga okushisa aphakeme. Uma ukuphumula kwengcindezi kwenzeka ekuqaleni kokuhlolwa, inani lokuphumula okwengeziwe liyakhuphuka kuqala futhi linenani eliphakeme phakathi nomjikelezo wokuqala. Engxenyeni enkulu yokuhlola ukukhiqiza amasampula e-gasket (ububanzi obungu-19mm obungaphandle, ububanzi obungaphakathi obuyi-15mm), ngokulungiswa okunwebekayo kuzocindezelwa esibonelweni ukuze izinga lokushisa lasekamelweni libe ngu-25%, bese kuthi ngo-25 ℃ lingene egumbini lokuhlola imvelo, izinga lokushisa libe ngu-25 ℃ ukugcina u-24h, bese lehla liye ku-2h, bese lehle liye ku-2h, ligcinwe ngo-20h, ligcinwe ngokulandelayo. -20 ~ 110 ℃ umjikelezo we-24h, sonke isikhathi sokuhlola ezingeni lokushisa lokuhlola, izinga lokushisa lokuhlola, ukuzimisela okuqhubekayo kwamandla. Isilinganiso samandla senziwa ngokuqhubekayo phakathi nesikhathi sokuhlola ezingeni lokushisa lokuhlola.
7. Umthelela Wokuqukethwe Kwe-Ethylene
7.1 Okuqukethwe kwe-ethylene kunomthelela omkhulu ekusebenzeni okuphansi kwezinga lokushisa kwama-polymers e-EPDM. Ama-polymers anokuqukethwe kwe-Ethylene kusuka ku-48% kuya ku-72% ahlolwe ngaphansi kokwakhiwa kokuvala uphawu okuphezulu. Konke kuhloswe ukunciphisa ukuhluka kwe-mooney viscosity ngokwethula i-ENB kulawa ma-polymer ahlukene.
Irabha ye-EPDM iyi-amorphous uma isilinganiso se-ethylene/propylene silingana futhi ukusatshalaliswa kwama-monomer amabili ochungechungeni lwe-polymer kungenangqondo. I-EPDM eno-48% kanye no-54% wokuqukethwe kwe-ethylene ayicwebezeli kukushisa kwegumbi noma ngaphezulu. Lapho okuqukethwe kwe-ethylene kufinyelela ku-65%, ukulandelana kwe-ethylene kuqala ukwanda ngenombolo nobude futhi kungakha amakristalu, abonwa eziqongweni zecrystallization kumajika e-DSC azungeze u-40°C. Uma iziqongo ze-DSC ziba nkulu, amakristalu akhayo aba makhulu.
7.2 Ngokungeziwe kumthelela wokuqukethwe kwe-ethylene ezicini zokushisa eziphansi okuxoxwe ngazo kamuva, usayizi we-crystallite uthinta ukukhululeka kokuxuba nokucutshungulwa kwezinhlanganisela eziqukethe amakristalu. Uma usayizi we-crystallite mkhulu, kudingeka ukushisa okwengeziwe nomsebenzi wokugunda esigabeni sokuxuba ukuze kuhlanganiswe ngokugcwele i-polymer nezinye izingxenye. Amandla enjoloba angahluziwe wezinhlanganisela ze-EPDM ayanda ngokuqukethwe kwe-ethylene okukhulayo. Ekwakhekeni kokuvala lapho umphumela wokuqukethwe kwe-ethylene ukalwe, ukwanda kokuqukethwe kwe-ethylene kusuka ku-50% kuya ku-68% kubangele okungenani ukwanda okuphindwe kane kumandla enjoloba. Ukuqina kwezinga lokushisa kwegumbi nakho kuyanda ngokukhula kokuqukethwe kwe-ethylene. I-Shore A ubulukhuni be-amorphous polymer adhesive ingu-63°, kanti u-Shore A ubulukhuni bepolymer enokuqukethwe okuphezulu kwe-ethylene kungu-79°. Lokhu kungenxa yokwanda kokulandelana kwe-ethylene, ukwanda kwe-crystallization ku-adhesive, kanye nokwanda okuhambisanayo kwama-polymers we-thermoplastic.
7.3 Uma ukuqina kukalwa emazingeni okushisa aphansi, ngokungafani nama-polymers ane-ethylene ephezulu, ama-polymers amorphous abonisa ushintsho oluncane lobulukhuni, kuyilapho ukuguqulwa kokuqina kokuqukethwe kwe-ethylene ephakeme akubonisi iphethini yomugqa futhi ukuqina kuhlala kuphezulu ekamelweni lokushisa, ukuze ama-polymers aqukethe okuqukethwe okuphezulu kwe-ethylene aqhubeke nokuba nobulukhuni obuphakeme kakhulu.
7.4 Isethi yokucindezela incike kakhulu ezingeni lokushisa lokuhlola. Uma ihlolwe ku-175 ° C, akukho mehluko ekucindezelweni okusethiwe phakathi kwanoma yimaphi ama-polymers (isethi ithonywa ukuklama kwe-compound kanye nokukhetha kwesistimu ye-vulcanization). Ngemva kokuncibilika kwamakristalu e-ethylene, i-polymer ibonisa ifomu le-amorphous, futhi ukuze kuhlolwe umphumela wokuqukethwe kwe-ethylene, ukuhlolwa kwenziwa ku-23 ° C. Ama-polymers anokuqukethwe okuphezulu kwe-ethylene ngokusobala ane-deformation ephakeme ehlala njalo (engaphezu kokuphindwe kabili), futhi umphumela wokuqukethwe kwe-ethylene mkhulu nakakhulu uma ihlolwe ku -20°C naku-40°C. Ama-polymer anokuqukethwe kwe-ethylene okungaphezu kuka-60% anokuguqulwa okuhlala njalo okuphezulu (>80%); ku--40°C, kuphela ama-polymer a-amorphous ngokugcwele anokuguqulwa okuphansi okungapheli (17%).
7.5 Umthelela Wokuqukethwe Kwe-Ethylene Ekuqineni Kwezinga Lokushisa Eliphansi Okuvela Ekuhlolweni Kwe-Gehman. Uma kubhekwa izinga lokushisa, ukuphakama kwekhona, kwehla ukwanda kokuqina (noma ukwanda kwe-modulus). Emazingeni okushisa aphansi, i-modulus yokuqina ikhula kakhulu ngokukhula kokuqukethwe kwe-ethylene. Kuma-polymers amorphous, i-T2 ingu--47°C, kuyilapho i-polymer yokuqukethwe kwe-ethylene ephakeme kakhulu ine-T2 engu -16°C kuphela.
7.6TR Ilinganisa ukubuyiselwa kokushwabana kwezifanekiso ngemva kokuqhwaza okunwetshiwe, okuqukethwe kwe-ethylene kunomthelela obalulekile endleleni yokuhlola, ephinda ifane nokuhlolwa kwe-Gehman.
Lokhu kufana nokuhlolwa kukaGehman. Ukuncipha (%) kwama-polymer ahlukahlukene kuyahlukahluka njengokusebenza kwezinga lokushisa, kanti ama-amorphous polymers ane-recovery ephezulu kakhulu yokuncipha emazingeni okushisa aphansi; Nokho, njengoba kubikezelwe, ukululama kuyawohloka njengoba okuqukethwe kwe-ethylene kukhula ngezinga lokushisa elinikeziwe.
ukululama kuyawohloka. Inani le-TR10 liyahlukahluka kusuka ku--53°C kuma-amorphous polymers kuya ku--28°C kuma-polymers ane-ethylene ephezulu.
7.7 Umjikelezo we-Compressive stress relaxation (CSR).
Umjikelezo. Cindezela ama-compounds, uwavumele aphumule ku-25°C amahora angu-24, bese uwabeka emjikelezweni wamazinga okushisa asukela ku -20°C kuya ku-110°C ngezikhathi ezithile amahora angu-24. Lapho icindezelwa okokuqala, ngemva kwesikhathi sokulinganisa, i-crystalline polymer E inokulahlekelwa okukhulu kokucindezeleka kune-amorphous polymer, futhi lapho yehliswa ku--20 ° C amandla okuvala ama-polymers amabili ayancipha, kuyilapho i-amorphous polymer A inokugcinwa okuphezulu kokucindezeleka (i-F / F0 ephezulu). Ukushisisa inhlanganisela ibe ngu-110°C kubuyisele amandla ako okuvala, futhi lapho kubuyiselwa phansi ku--20°C, amandla okuvala asele e-polymer ecwebezelayo ayengaphansi kuka-20% yenani layo, ngokuvamile elibhekwa njengeliphansi kakhulu uma lisetshenziswa kakhulu, lapho i-amorphous polymer igcina ngaphezu kuka-50% wamandla ayo okuvala, futhi ibe ne-amorphous recovery polymer futhi ibe ne-amorphous recovery polymer. Umjikelezo olandelayo uveze iziphetho ezifanayo. Kuyacaca ukuthi ama-amorphous polymers angcono kakhulu ekuvaleni izinhlelo zokusebenza lapho izinga lokushisa eliphezulu neliphansi liyadingeka.
8. Umthelela Wokuqukethwe kwe-Diolefin
Ukuze kuhlinzekwe ngephoyinti elingagcwalisiwe elidingekayo ukuze kwenziwe i-vulcanization, ama-diolefin angahlanganisiwe afana ne-ENB, HX kanye ne-DCPD engezwa kuma-ethylene propylene polymers. Ibhondi eyodwa ekabili isabela ku-matrix ye-polymer, kuyilapho eyesibili isebenza njengomphelelisi weketango lemolekyuli eyenziwe nge-polymerized futhi ihlinzeka ngendawo yokuvuvuka kwe-vulcanization ephuzi nesibabule. Umthelela we-ENB uhlolwe kumaphrofayela ebha ye-windshield (imvula). Ama-Polymers aqukethe u-2%, 6% no-8% ENB aqhathaniswa.Ukungezwa kwe-ENB kube nomthelela omkhulu ezicini ze-vulcanization kanye nokuminyana kwe-crosslink. I-modulus yenyukile ngenkathi ubude behla kakhulu. Ukuqina kwanda futhi isethi yokucindezela yaba ngcono ngesikhathi sokukhuphuka kwezinga lokushisa. Njengoba okuqukethwe kwe-ENB kwanda, isikhathi sokushaja siba sifushane.
I-ENB iyinto ye-amorphous, futhi uma yengezwa kumgogodla we-polymer, iphazamisa i-crystallization yengxenye ye-ethylene ye-polymer, ukuze ama-polymers anokuqukethwe okufanayo kwe-ethylene angatholakala, futhi okuqukethwe okuphezulu kwe-ENB kuthuthukisa izakhiwo eziphansi lokushisa. Ezingeni lokushisa legumbi, okuqukethwe okuphezulu kwe-ENB kuthuthukisa kancane isethi yokuminyanisa ngenxa yokuminyana okuthuthukisiwe kwe-crosslink. Kodwa-ke, emazingeni okushisa aphansi, isethi yokuminyanisa yama-polymers anokuqukethwe okuphezulu kwe-ENB ingcono kakhulu kunaleyo yama-polymers anokuqukethwe okungu-2% kwe-ENB. Umthelela wokuqukethwe kwe-ENB ku-brittleness lokushisa, ukuhoxiswa kwezinga lokushisa, nokuhlolwa kuka-Gehman akuzange kubonise umehluko obalulekile ku-brittleness lokushisa phakathi kwama-polymers ngokuvamile, futhi ekuhlolweni kwe-Gehman nokuhlolwa kwe-TR, i-polymer ngayinye ibonise ukuthuthuka kwezakhiwo zezinga lokushisa eliphansi ngokuqukethwe okwandayo kwe-ENB.
9. Umthelela we-mooney Viscosity Ezimpahleni Zezinga Lokushisa Eliphansi
Kwaziwa kahle ukuthi i-mooney viscosity (isisindo samangqamuzana) inomthelela omkhulu ekuziphatheni kokucubungula kwama-elastomer. Kuzinhlelo zokusebenza ze-extrusion kanye nokubumba Kuzinhlelo zokusebenza ze-extrusion kanye nokubumba, kubalulekile ukukhetha inhlanganisela enenani elifanele le-Money viscosity. Kusetshenziswa ukwakheka okufanayo okwasetshenziselwa ukuphenya umthelela we-monomer yesithathu, i-ENB, ezindaweni ezisezingeni eliphansi ukuze kuhlolwe i-Mooney viscosity, ama-polymer ane-Mooney viscosity engu-30, 60, no-80 aqhathaniswa, futhi i-money viscosity yezinhlanganisela yanda njengoba i-viscosity ye-Moneyy yama-polymers asetshenzisiwe yanda. Amandla aqinile, i-modulus, namandla enjoloba aluhlaza akhuphuka ngokukhula kwe-Mooney viscosity. Umthelela we-Mooney viscosity ezicini zokushisa eziphansi ze-EPDM wawungabalulekile. Nokho, ukucindezelwa unomphela deformation ekamelweni lokushisa, -20°C no -40°C iyanda ngokwanda kwamangqamuzana. Kodwa-ke, ukucindezela okubekwe ekamelweni lokushisa, -20 ° C kanye -40 ° C akuzange kushintshe kakhulu ngokukhula kwesisindo samangqamuzana, kuyilapho ukucindezela okubekwe emazingeni okushisa aphakeme (175 ° C) kubonisa izinguquko ezithile ze-mooney viscosities ephakeme ye-adhesive EPDM.
10. Isiphetho
Okuqukethwe kwe-ethylene ne-diolefin kunomthelela omkhulu ekusebenzeni kwe-EPDM elastomers ekusetshenzisweni kokushisa okuphansi, nama-polymers anokuqukethwe okuphansi kwe-ethylene enza kahle futhi ama-polymers anokuqukethwe okuphezulu kwe-diolefin athuthukayo ngenxa yokuphazamiseka kwe-crystallization yengxenye ye-ethylene ye-polymer. Ama-polymers wokuqukethwe kwe-ethylene ephansi kufanele asetshenziswe lapho ukusebenza kwezinga lokushisa eliphansi kuwumkhawulo.
