Thermoplastics ang lo takin elastomer hi temperature hrang hrangah leh an glass transition temperature (Tg) aia sang zawkah hman a ni tlangpui. Thermoplastics aiin elastomers thatna chu tensile state (high elasticity) atanga a lo harh chhuah vek theihna te, chubakah generalized elasticity, hardness hniam leh modulus property hniam te a ni. Elastomer hi room temperature hnuai lama hman a nih chuan a hardness a sang a, modulus a sang a, elasticity a tlahniam bawk. Room temperature hnuai lama elastomer hman a nih chuan hardness a sang a, modulus a sang a, elasticity a tlahniam (low tensile) a, compression set a sang bawk. Elastomer chungchanga harsatna awm dan azirin a rualin thil pahnih a thleng thei - glass hardening leh partial crystallization - CR, EPDM, NR te hi crystallization lantir thei elastomer entirnan thenkhat an ni.
1. Temperature hniam testing chungchang tlangpui
Temperature hniam takah polymer property characterize nan kum tam tak chhung chu Brittleness, compression permanent deformation, retraction, hardening leh cryogenic hardening te hi hman a ni tawh a. Compressive stress relaxation hi thil thar tak a ni a, boruak hrang hrang hnuaia hun engemaw chen chhunga thil pakhat sealing force tehna a ni.
2. Brittleness Temperature a ni
ASTM D 2137 chuan brittleness temperature chu vulcanized rubber-in impact condition bik hnuaia fracture emaw rupture emaw a lantir lohna temperature hniam ber tihna a ni. Rubber specimen panga, a pianzia ruat lawk tawh siamin, chamber emaw liquid medium emaw-ah dahin, temperature ruat saah 3±0.5min chhung dah a ni a, chutah chuan impact velocity 2.0±0.2m/s pek a ni. Specimen te hi lakchhuah niin impact emaw rupture test emaw an nei thin. Specimen hi lakchhuah a ni a, impact emaw fracture emaw test a ni a, a chhe vek lo. Test hi brittleness temperature thlengin an ti leh a - a hniam berna hmuna fracture hmuh lohna chu 1°C hnaih tak a ni.
3. Temperature hniam Compression Set leh Temperature hniam Hardening
Low-temperature compression set-a test dan hi standard compression set-a test dan nen a inhnaih hle a, chu chu temperature chu energy method engemaw, dry ice, liquid nitrogen, emaw mechanical method hmanga control a nih loh chuan, a value chu preset temperature atanga ± 1°C chhungah a awm a ni. Fixture atanga a lo chhuah hnuah pawh specimen chu preset low temperature-ah dahin, diameter 29 mm leh thickness 12.5 mm-ah molded a ni bawk. Low-temperature compression set hi indirect method a ni a, chu chu compound sawi tur a hman dan sealing nan a ni. Compressive stress relaxation hi direct method a ni a, a hnuah kan sawi leh ang. Low temperature hardening pawh hi vulcanized compression set specimen (29mm x 12.5mm) hmanga hriat a ni tlangpui a, mahse low temperature control-ah test leh a ni a, chu chu compression set-a hman ang chiah a ni a, chutah chuan an set temperature ang chiah khan test leh a ni. Hardening leh low-temperature compression set hi cooling hian direct-in a nghawng a, mahse polymer crystallize duhna hian a nghawng bawk a, crystallization rate chu temperature-ah a innghat a, eg, CR hi -10°C velin a crystallize rang ber a, chutah chuan temperature hniam zawkah a tlahniam a, a chhan ber chu polymer chain segment-te immobility vang a ni ber (molecular chain-te chu a freeze hmain siamthat leR hi -10°C velin a crystallize rang ber a, chutah chuan temperature hniam zawkah a tlahniam a, a chhan ber chu polymer chain segment-te immobility vang a ni ber (molecular chain-te chu a freeze hmain siamthat lehna).
4. Gehman Low Temperature a tiharh theih
ASTM D 1053 chuan low-temperature hardening method chu hetiang hian a sawi a: elastic polymer specimen series chu torsional constant hriat tawh wire-ah fixed-in an inzawm a, wire tawp dang chu wire chu twisted theihna tur torsion head-ah an dah bawk. Specimen te chu heat transfer medium-ah temperature pangngai aia hniam takah an thun a, chutih lai chuan torsion head chu 180° in an twist a, chutah chuan specimen te chu specimen flexibility leh stiffness inverse-a innghat zat (180° aia tlem) in an twist a ni. Tichuan goniometer zat hmangin specimen twist zat, twist angle leh rubber material hardness te chu hriat theih a ni. Hetih lai hian system temperature chu a sang zauh zauh a, angle of twist against temperature plot siam a ni. Modulus-in T2, T10, leh T100 a thlenna temperature chu room temperature-a modulus value nen a inang tih record a ni tlangpui.
5. Temperature hniam tak hnutchhiah (TR Test) .
TR test hi specimen pakhatin tensile state-a a theihna tehna atan hman a ni a, chu chu compressive permanent deformation leh compressive stress relaxation hmanga compressive stress atanga teh compressive stress relaxation hmanga temperature hniam effects hriat theihna tur a ni. A hmaa kan sawi tawh ang khan NR leh PVC ang chi polymer tam tak chu temperature hniam takah an crystallize ang a, mahse stretching hian a crystallize thei bawk a, hei hian temperature hniam property en hian thil dang a thlen thei a ni. Exhaust suspension ang chi evaluation application atan chuan TR under tension hi a remchang hle a, hman fo a ni. He test-ah hian specimen chu a sei (a tam zawkah chuan 50% emaw 100%) a ni a, a sei zawngin a vawt (frozen) a ni. Specimen chu chhuah a ni a, chutih lai chuan specimen lo chhuah lehna tehna tur rate ruat saah temperature tihsan a ni a, a shrinkage sei zawng teh a ni a, elongation record a ni. Specimen 10%, 30%, 50%, leh 70% a tlahniamna temperature chu TR10, TR30, TR50, leh TR70 tia chhinchhiah a ni tlangpui. TR10 hi brittleness temperature nen a inzawm a; TR70 hi low-temperature compression-a specimen-a permanent deformation nen a inzawm a; leh TR10 leh TR70 inthlauhna chu specimen crystallization tehna atan hman a ni (a danglamna a tam poh leh crystallize duhna a sang zawk).
6 . A rilru a buai em em a, a rilru a hah em em bawk a. .
CSR test hmang hian sealing materials te hnathawh dan leh an dam chhung tur hrilhlawkna siam theih a ni. Elastomeric compound chu constant deformation pek a nih chuan combined force a siam a, chu material chuan he force hi environment range engemaw zat chhunga a vawn theihna hian a seal theihna a teh a ni. Physical leh chemical mechanism pahnih hian stress relaxation a siam a, hun leh temperature a zirin factor pakhatin a thunun ang a, physical relaxation hi temperature hniam takah hmuh a ni a, stress pek a nih hnu lawkah, chu chuan chain rearrangement leh rubber-filler leh filler-filler surface-a inthlak danglamna a thlen a, stress removal system relaxation chu reversible a ni. Temperature sang zawkah chuan chemical composition hian relaxation rate a tichiang a, chutih lai chuan physical process te chu a tlem tawh a, chemical relaxation chu a let leh thei lo a, chu chuan chain breakage leh cross-linking reaction a thlen thin. Temperature cycling emaw temperature sang nghal hian elastomer-a stress relaxation-ah nghawng a nei thei a ni. CSR test neih chhung hian test specimen chu dah a ni
CSR testing neih chhung hian test specimen chu temperature sang zawka dah a nih chuan stress relaxation a tipung a ni. Test tir lamah stress relaxation a awm chuan additional relaxation a tam hmasa ber a, cycle hmasa berah value sang ber a nei bawk. Gasket sample siamna tur tensile lian test piece-ah (19mm pawn lam diameter, chhung lam diameter 15mm), elastic fixture neiin specimen-ah an room temperature thickness 25% thlengin compress a ni ang a, 25 °C-ah environmental test chamber-ah, temperature 25 °C-ah 24h vawng reng turin, chutah chuan -20 °C-ah tihhniam a ni ang a, chu chu dah chhunzawm zel a ni ang 24h, chumi hnuah -20 ~ 110 °C cycle 24h inkar temperature dang, test temperature-a test hun zawng zawng, test temperature, continuous force determination. Force tehna hi test hun chhung zawngin test temperature-ah tih chhunzawm zel a ni.
7. Ethylene Content-in nghawng a neih dan
7.1 Ethylene awm zat hian EPDM polymer-te temperature hniam performance-ah nghawng lian ber a nei a ni. Ethylene content 48% atanga 72% inkar polymer te chu quality tha tak sealing formulations hmangin an zirchiang a. An vai hian heng polymer hrang hrangah hian ENB dahin mooney viscosity danglamna tihtlem an tum vek a ni.
EPDM rubber hi ethylene/propylene ratio a inang a, polymer chain chhunga monomer pahnih distribution chu random a nih chuan amorphous a ni. EPDM 48% leh 54% ethylene awmna chu room temperature emaw a aia sang emaw-ah a crystallize lo. Ethylene content 65% a thlen chuan ethylene sequence te chu a tam leh sei zawng a pung tan a, crystal a siam thei a, chu chu DSC curve 40°C vel a crystallization peaks-ah hmuh a ni. DSC peaks a lian poh leh crystal lo piang chu a lian zawk thin.
7.2 A hnua kan sawi tur temperature hniam property-a ethylene content-in nghawng a neih bakah hian crystallite size hian crystal awmna compound mix leh process awlsamna a nghawng a ni. Crystallite size a lian chuan mixing stage-ah polymer chu component dangte nen a inzawm kim theih nan heat leh shear work a ngai tam zawk a ni. EPDM compound raw rubber strength hi ethylene a tam chuan a sang chho zel a ni. Ethylene awm zat nghawng tehna hmuna sealing formulation-ah chuan ethylene awm zat 50% atanga 68% a tihpun chuan rubber chakna chu a let li tal a tipung a ni. Ethylene a tam chuan room-temperature hardness pawh a sang chho zel bawk. Amorphous polymer adhesive-a Shore A hardness chu 63° a ni a, chutih laiin ethylene tamna ber polymer-a Shore A hardness chu 79° a ni thung. Hei hi ethylene sequence a san vang te, adhesive-a crystallization a pun vang te, leh a inmil thermoplastic polymers a pun vang te a ni.
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7.4 Compression set hi test temperature-ah a innghat nasa hle. 175°C-a test a nih chuan polymer zingah compression set-ah danglamna a awm lo (set hi compound design leh vulcanization system thlan danin a nghawng a ni). Ethylene crystals te chu a hmin hnuah polymer hian amorphous form a lantir a, ethylene content-in nghawng a neih dan enfiah nan 23°C-ah test an nei a ni. Ethylene tamna polymer-te hian permanent deformation sang zawk (a let hnih aia tam) an nei tih a chiang a, -20°C leh -40°C-a test a nih chuan ethylene awm zat nghawng chu a lian zawk a ni. Polymer 60% aia tam ethylene awmnaah hian permanent deformation sang tak (>80%) a awm a; -40°C-ah chuan fully amorphous polymer chauh hian permanent deformation hniam (17%) an nei a ni.
7.5 Gehman Test atanga Low Temperature Hardening-a Ethylene Content-in nghawng a neih dan. Temperature pek a nih chuan corner a san chuan stiffness tihpun (or modulus tihpun) a hniam zawk. Temperature hniam takah chuan ethylene awm zat a san chuan stiffness modulus chu nasa takin a pung a ni. Amorphous polymer tan chuan T2 chu -47°C a ni a, ethylene tamna ber polymer chuan T2 chu -16°C chauh a nei thung.
7.6TR Extension freezing hnua specimen-te shrinkage recovery tehnaah hian ethylene awm zat hian test method-ah nghawng lian tak a nei a, hei hi Gehman test nen a inang leh ta a ni.
Hei hi Gehman test nen a inang hle. Polymer hrang hrangte shrinkage (%) hi temperature a zirin a danglam a, amorphous polymer te hian temperature hniam takah shrinkage recovery sang ber an nei a mahse, sawi lawk angin, temperature pek tawhah ethylene awm zat a san chuan recovery chu a chhe ta hle.
dam lehna a chhe ta hle. TR10 hlutna hi amorphous polymer tan -53°C atanga ethylene tamna polymer tan -28°C thlengin a inang lo.
7.7 Compressive stress relaxation (CSR) cycle hmanga tihchhuah a ni
Thirsakawr. Compound te hi compress la, 25°C ah 24 h chhung relax turin dah la, chutah chuan -20°C atanga 110°C inkar temperature cycle ah 24 h chhung intermittent takin dah rawh. A vawi khatna atana compress a nih chuan equilibration period hnuah crystalline polymer E hian amorphous polymer aiin stress a hloh nasa zawk a, -20°C-a tihhniam a nih chuan polymer pahnih sealing force a tlahniam a, amorphous polymer A erawh chuan stress retention sang tak a nei thung (F/F0 sang zawk). Compound chu 110°C-a tihlum chuan a sealing force chu a siam ṭha leh a, -20°C-a tihhniam leh a nih chuan crystalline polymer-a sealing force la awm chu a hlutna aṭanga 20% aia tlem a ni a, hei hi a tlangpuiin hmanna tam zawkah chuan a hniam lutuk nia ngaih a ni a, amorphous polymer hian a sealing force 50% aia tam a vawng reng a, amorphous polymer chuan a sealing force 50% aia tam a vawng reng a, amorphous polymer chuan a aia recovery sang zawk a nei leh ta a ni crystalline polymer a ni. A cycle dang pawhin hetiang bawk hian thutlukna a siam ta a ni. Temperature sang leh hniam performance mamawhna hmuna sealing application atan amorphous polymers hi a tha zawk tih a chiang hle.
8. Diolefin Content-in nghawng a neih dan
Vulcanization atana mamawh unsaturated point pe turin ethylene propylene polymer-ah hian non-conjugated diolefins ENB, HX leh DCPD te dah a ni. Double bond pakhat chu polymer matrix-ah a inrem a, a pahnihna chu polymerized molecular chain-a complement angin a thawk a, sulfur yellow vulcanization atan vulcanization point a pe bawk. ENB hian a nghawng dan chu windshield (rain) bar profile-ah an zirchiang a. polymer 2%, 6% leh 8% ENB awmna te chu khaikhin a ni.ENB dah belh hian vulcanization characteristic leh crosslink density ah nghawng lian tak a nei a ni. Modulus a pung a, elongation erawh a tlahniam hle thung. Temperature sang chhoh lai hian hardness a sang a, compression set pawh a tha zawk bawk. ENB content a san chuan charring hun a tawi chho zel bawk.
ENB hi amorphous material a ni a, polymer backbone-a dah a nih chuan polymer-a ethylene portion crystallization a tibuai a, chutiang chuan ethylene content inang polymer a awm thei a, ENB tam zawk chuan low-temperature property a ti tha zawk a ni. Room temperature-ah chuan ENB content sang zawk hian crosslink density a that avangin compression set a ti tha deuh hlek a ni. Mahse, temperature hniam takah chuan ENB content sang zawk nei polymer te compression set chu 2% ENB content nei polymer te aiin a tha zawk tih a chiang hle. ENB content-in brittleness temperature, temperature retraction, leh Gehman’s test-a nghawng a neih danah chuan polymer-te zingah a tlangpuiin brittleness temperature-ah danglamna lian tham a awm lo a, Gehman’s test leh TR test-ah chuan polymer tin hian ENB content a san chuan low-temperature property-ah hmasawnna a lantir a ni.
9. Mooney Viscosity hian Low Temperature Properties a nghawng dan
Mooney viscosity (molecular mass) hian elastomer-te processing behavior-ah nghawng lian tak a nei tih hriat lar tak a ni. Extrusion leh molding hmannaah Extrusion leh molding hmannaah chuan Mooney viscosity value tling tak nei compound thlan a pawimawh hle. Mooney viscosity enfiahna atana monomer pathumna ENB-in low-temperature property-a nghawng a neih dan zirchianna atana hman ang chiah formulation hmangin Mooney viscosity 30, 60, leh 80 nei polymer-te chu khaikhin a ni a, polymer hmante Mooney viscosity a san chuan compound-te Mooney viscosity a sang chho zel a ni. Mooney viscosity a san chuan tensile strength, modulus leh raw rubber strength te chu a sang chho zel a ni. Mooney viscosity hian EPDM temperature hniam property a nghawng dan chu a langsar lo hle. Mahse, room temperature, -20°C leh -40°C-a compression permanent deformation chu molecular mass a san chuan a pung zel a ni. Mahse, room temperature, -20°C leh -40°C-a compression set chu molecular mass a san chuan a danglam vak lo a, chutih laiin temperature sang (175°C)-a compression set chuan EPDM adhesives-a mooney viscosities sang zawk tan danglamna engemaw zat a lantir thung.
10. Thutawp
Ethylene leh diolefin awm zat hian EPDM elastomer-te hnathawh danah nghawng lian tak a nei a, temperature hniam zawka hmanna polymer-te chuan an thawk tha hle a, diolefin eed04838b3c9=MPU Compound hi China siamtu Herchy siam a ni . Tunah hian MPU Compound quality tha tak lei rawh!
