Thermoplastics ang lo takin elastomer te hi a tlangpuiin temperature hrang hrangah an hmang a, an glass transition temperature (TG) aia sang zawkah an hmang bawk. Elastomer te hian thermoplastics aiin an thatna chu tensile state atanga an dam leh theihna (high elasticity), chubakah an generalized elasticity, low hardness leh low modulus property te an neih theihna a ni. Elastomers te hi room temperature aia hniam zawka hman an nih chuan hardness a sang a, modulus a sang a, elasticity a tlahniam bawk. Elastomers te hi room temperature aia hniam zawka hman a nih chuan hardness tihpun duhna, modulus tihpun duhna, elasticity tlahniam (low tensile) leh compression set tihpun tendency a awm. Elastomer-a harsatna awm dan azirin thil thleng pahnih chu a rualin a awm thei - glass hardening leh partial crystallization - CR, EPDM, NR te hi crystallization lantir thei elastomer entirnan thenkhat an ni.
1. Temperature hniam test dan tlangpui .
Brittleness, compression permanent deformation, retraction, hardening leh cryogenic hardening te hi kum tam tak chhung chu temperature hniam zawka polymer property te characterize nan an hmang tawh a ni. Compressive stress relaxation hi a thar deuh a, boruak dinhmun hrang hrang hnuaia hun engemaw chen chhunga material pakhat sealing force hriatfiahna lam a ngaihtuah a ni.
2. A brittleness temperature .
ASTM D 2137 chuan brittleness temperature chu vulcanized rubber-in impact conditions tarlan hnuaia fracture emaw rupture emaw a lantir lohna temperature hniam ber a ni tih a sawi. Rubber specimen panga, pre-determined shape siam, chamber emaw liquid medium-a dah, set temperature set-a 3±0.5min-a dah, chutah chuan impact velocity 2.0±0.2m/s pek a ni. Specimen te chu lakchhuah a ni a, impact emaw rupture test emaw an nei thin. Specimen chu lakchhuah a ni a, impact emaw fracture emaw a awm leh awm loh test a ni a, chu zawng zawng chu chhiatna awm lovin a ni. Test chu brittleness temperature thlengin an ti leh a - fracture hmuh lohna temperature hniam ber chu 1°C hnaih tak a ni.
3. Temperature hniam compression set leh temperature a harh lohna tur .
Test procedure for low-temperature compression set chu standard compression set atan chuan a hnaih hle a, chu chu temperature chu energy method thenkhat hmanga control a nih loh chuan, dry ice, liquid nitrogen, emaw mechanical methods te ang chi a ni a, a value chu preset temperature ± 1°C chhungah a awm a ni. Fixture atanga recovery hnuah specimen chu preset low temperature-ah dahin, diameter 29 mm leh thickness 12.5 mm-ah an mold bawk. Low-temperature compression set hi indirect method a ni a, a sawi tur compound hmanna tur sealing 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) hmangin an teh tlangpui a, mahse low temperature control-ah an test leh a, chu chu compression set-a awm ang chiah a ni a, chutah chuan an set temperature nen a inang leh a ni. Hardening leh low-temperature compression set hi cooling-in direct-in a nghawng a, mahse polymer-in crystallize a duhna avang pawhin, crystallization rate chu temperature-ah a innghat a, eg, CR crystallize-ah chuan -10°C velin a tlahniam a, chutah chuan temperature hniam zawkah a tlahniam a, chu chu polymer chain segment-te immobility vang a ni ber (molecular chains-te chu rearrangement hmaa freeze an ni).
4. Gehman a hniam lam a harh dawn.
ASTM D 1053 chuan low-temperature hardening method chu hetiang hian a sawi a: elastic polymer specimen series chu wire-ah torsional constant hriat tawhah a innghat a, wire tawp dang chu torsion head-ah a inzawm a, chu chu wire chu twist theihna tur a ni. Specimen te chu heat transfer medium ah chuan temperature bik bik ah chuan a tlangpui hnuaiah an thun a, chutih lai chuan torsion head chu 180° in an twist a, chutah chuan specimen te chu specimen te flexibility leh stiffness inverse ah a innghat a, chu chu a zat (180° aia tlem) in an twist a ni. Chumi hnuah chuan goniometer zat hmangin specimen twist zat, angle of twist leh rubber material hardness te chu teh rawh. Hetiang dinhmunah hian system temperature chu a sang chho zauh zauh a, temperature leh temperature nena inzawm angle of twist plot a awm bawk. Modulus-in T2, T10, leh T100 a thlen theihna temperature chu room temperature-a modulus value nen a inang tlangpui.
5. Temperature hniam zawka kalpui (TR test) .
TR test hmang hian compressive permanent deformation leh compressive stress relaxation tihfel a nih chuan compressive stress hmanga teh a nih chuan tensile state-a specimen awm theihna tehna atan hman a ni. A hmaa kan sawi tawh ang khan NR leh PVC ang polymer tam tak chu temperature hniam takah chuan an crystallize ang a, mahse stretching pawh a crystallize thei bawk a, hei hian temperature hniam property en hian factor dang a thlen thei bawk. Exhaust suspension ang chi evaluation application atan chuan TR under tension hi a remchang hle a, hman fo thin a ni. He test-ah hian specimen chu a sei (a tam zawk chu 50% emaw 100% emaw) a ni a, elongated state-ah chuan a frozen a ni. Specimen chu a chhuak a, chutih lai chuan specimen recovery tehna tur rate ruat sain a sang a, a shrinkage sei zawng chu teh a ni a, a sei zawng chu record a ni. Specimen 10%, 30%, 50%, leh 70% te a tlahniam thin temperature te hi TR10, TR30, TR50, leh TR70 anga ngaih a ni tlangpui. TR10 hi brittleness temperature nen a inzawm a; TR70 hi low-temperature compression-a specimen-te permanent deformation nen a inzawm a; leh TR10 leh TR70 inkar danglamna chu specimen crystallization tehna atan hman a ni (a danglamna a tam poh leh crystallize duhna a sang zawk).
6 . Temperature hniam compressive stress relaxation (CSR) .
CSR test hmang hian sealing materials performance leh life chungchangah prediction siam theih a ni. Elastomeric compound chu a inthlak danglam reng a nih chuan, chakna inzawmkhawm siam a ni a, chu thil chuan he chakna hi environment range engemaw zat chhunga a vawn reng theihna chuan a seal theihna a teh a ni. Physical leh chemical mechanism pahnih hian stress relaxation a thlen a, hun leh temperature a zirin, factor pakhat chu a thunun ang a, temperature hniam takah physical relaxation hmuh a ni ang 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 a let leh theih 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 inthlak danglam thei lo a, chu chuan chain breakage leh cross-linking reaction a thlen thin. Temperature cycling emaw temperature sang nghal emaw hian elastomers-a stress relaxation-ah nghawng a nei thei a ni. CSR test neih chhung hian test specimen chu dah a ni .
CSR test lai hian test specimen chu temperature sang tak a nih chuan stress relaxation a sang chho thin. Test tir lamah stress relaxation a awm chuan additional relaxation a tam zawk a, cycle hmasa berah value sang ber a nei a ni. Gasket sample siam chhuahna tur test piece tensile lian takah (19mm outer diameter, inner diameter of 15mm), elastic fixture nei chu specimen-ah an room temperature thickness 25%-ah an compress ang a, 25 °C-ah environmental test chamber-ah an compress ang a, 24h, leh a hnuah 24h, leh a hnuah 24h, leh a hnuaia mi ang -20 ~ 110 °C cycle 24h, test hun chhung zawng zawng test temperature, test temperature, continuous force determination. Force measurement hi test hun chhung zawngin test temperature-ah tih chhunzawm zel a ni.
7. Ethylene awm zat a nghawng dan .
7.1 Ethylene awm zat hian EPDM polymer-te temperature hniam performance-ah nghawng a nei lian ber a ni. Ethylene awm zat 48% atanga 72% inkar polymer te chu high quality sealing formulations hmangin an zirchiang a. An vai hian Mooney viscosity danglamna tihtlem an tum a, heng polymer hrang hrangah hian ENB an rawn luh tir a ni.
EPDM rubber hi ethylene/propylene ratio a inang a, polymer chain a monomer pahnih distribution chu random a nih chuan amorphous a ni. EPDM 48% leh 54% ethylene awm zat chu room temperature emaw a aia sang emaw a crystallize lo. Ethylene content 65% a thlen chuan ethylene sequences te chu a number leh a sei zawng a sang tan a, crystal a siam thei a, chu chu DSC curves 40°C vel a crystallization peaks ah hmuh theih a ni. DSC peaks a lian chuan crystals a lo awm tam zawk thin.
7.2 Ethylene content-in a hnu lama kan sawi tur temperature low temperature property-a nghawng a neih bakah hian crystallite size hian crystal awmna compound mixing leh processing awlsamna a nghawng a ni. Crystallite size a lian chuan mixing stage-ah heat leh shear work tam zawk a ngai a, chu chuan polymer chu component dangte nen a blend kim vek a ni. EPDM compounds raw rubber strength chu ethylene a pun zel chuan a sang chho zel a. Sealing formulations-ah chuan ethylene content-in nghawng a neih dan tehnaah chuan ethylene awm zat 50% atanga 68%-a tihpun a nih chuan rubber chakna chu a let li talin a pung a ni. Room-temperature hardness pawh ethylene a pun zel chuan a pung zel bawk. Amorphous polymer adhesive-a shore a hardness chu 63° a ni a, chutih laiin shore-ah chuan ethylene tam ber polymer-a hardness chu 79° a ni thung. Hei hi ethylene sequence a san vang te, adhesive-a crystallization a pun vang te, a inmil tur thermoplastic polymer te vang a ni.
7.3 Hardness chu temperature hniam taka teh a nih chuan, ethylene tamna polymer-te nen a danglamna chu, amorphous polymer-te chuan hardness-ah danglamna an lantir tlem zawk a, chutih laiin ethylene tam zawk awmnaah chuan hardness inthlak danglamna chuan linear pattern a lantir lo va, room temperature-ah chuan hardness chu a sang reng a, chutiang chuan ethyne tam zawk awmna polymer-te chuan temperature sang ber an nei chhunzawm zel a ni.
7.4 Compression set hi test temperature-ah a innghat nasa hle. 175°C-a test a nih chuan polymer pakhat mahah compression set-ah danglamna a awm lo (set hi compound design leh vulcanization system thlan danin a nghawng a ni). Ethylene crystals a hmin hnuah polymer chuan amorphous form a lantir a, ethylene awm zat a nghawng dan enfiah nan 23°C ah test an nei bawk. Ethylene content sang zawk nei polymer te hian permanent deformation sang zawk an nei tih a chiang a (a let hnih aia tam), ethylene content hian -20°C leh -40°C-a test a nih chuan a nghawng a lian zawk hle. Polymer 60% aia tam ethylene awm zat chu permanent deformation sang tak (>80%) a ni a; -40°C ah chuan fully amorphous polymers chauh hian permanent deformation hniam (17%) an nei a ni.
7.5 Gehman test atanga low temperature hardening-a ethylene awm zatin nghawng a neih dan. Temperature pek a nih chuan corner a san chuan stiffness a san (or modulus tihpun) a hniam zawk. Temperature hniam takah chuan stiffness modulus chu ethylene a pun zel chuan nasa takin a pung a ni. Amorphous polymer tan chuan T2 hi -47°C a ni a, ethylene content polymer sang ber chu T2 -16°C chauh a ni thung.
7.6TR Measuring Specimens recovery Extension freezing hnua recovery ethylene content hian test method-ah nghawng lian tak a nei a, hei hi Gehman test nen a inang leh a ni.
Hei hi Gehman test nen a inang hle. Polymer hrang hrang shrinkage (%) chu 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 a nih chuan ethylene content a san avangin recovery a tlahniam a ni.
Recovery a tlahniam. TR10 value hi amorphous polymers tan -53°C atanga ethylene tamna polymer tan -28°C thleng a ni.
7.7 Compressive Stress Relaxation (CSR) cycle 1000 a awm a.
Thirsakawr. Compound te chu compress la, 25°C ah 24 h chhung relax turin dah la, chutah chuan -20°C atanga 110°C thleng 24 h chhung chu a inkar ah dah rawh. A vawi khatna atana compress a nih chuan, equilibration period hnuah, crystalline polymer E hian amorphous polymer aiin stress a hloh sang 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 dah leh a nih chuan, crystalline polymer-a sealing force la awm chu a hlutna 20% aia tlem a ni a, chu chu a tlangpuiin hmanna tam zawk atan chuan a hniam lutuk nia ngaih a ni a, amorphous polymer chuan a sealing force 50% aia tam a vawng reng a, amorphous polymer chuan crystalline aiin recovery a nei sang leh a ni. Cycle dang pawhin chutiang bawka thutlukna a siam ve bawk. Amorphous polymers hi sealing application atan a tha zawk tih a chiang a, chutah chuan temperature sang leh hniam performance a ngai a ni.
8. Diolefin awm zat a nghawng dan .
Vulcanization atana mamawh unsaturated point pek tur chuan ethylene propylene polymer-ah hian non-conjugated diolefins ENB, HX leh DCPD te an dah tel a ni. Double bond pakhat chu polymer matrix-ah a inrem a, a pahnihna chu polymerized molecular chain nena inzawm angin a thawk a, sulfur yellow vulcanization atana vulcanization point a pe bawk. ENB-in nghawng a neih 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 nasa takin a tlahniam thung. Hardness a sang a, compression set pawh a sang chho zel a, temperature a sang chho zel bawk. Enb content a san chuan charring time pawh a tawi deuh deuh thin.
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 chiah chiah polymer te chu hmuh theih a ni a, ENB-a content sang zawk chuan low-temperature property a ti tha zawk a ni. Room temperature-ah chuan enb content sang zawk chuan crosslink density a tha zawk 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-a test-a nghawng a neih dan chuan polymer-te inkara brittleness temperature-ah danglamna lian tham a awm lo a, Gehman-a test leh TR test-na atan chuan polymer tin hian enb content tihpun rualin low-temperature property-ah hmasawnna an lantir a ni.
9. Mooney viscosity hian temperature hniam property a nghawng dan .
Mooney viscosity (molecular mass) hian elastomers-te processing behavior-ah nghawng lian tak a nei tih chu hriat lar tak a ni. Extrusion leh molding application-ah chuan extrusion leh molding application-ah chuan Mooney viscosity value tling tak nei compound thlan a pawimawh hle. Mooney viscosity, Mooney viscosity nei polymer 30, 60, leh 80 nei polymer te enfiah nan monomer pathumna, ENB, low-temperature property-a nghawng zir chianna formulation ang chiah hmangin, polymer-te Mooney viscosity hman a nih chuan Mooney viscosity chu a pung a ni. Mooney viscosity a san chhoh zel chuan tensile strength, modulus, leh raw rubber strength a sang chho zel a. EPDM temperature hniam property-a Mooney viscosity-in nghawng a neih 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 a ni. Mahse, room temperature, -20°C leh -40°C-a compression set chu molecular mass a san chuan a danglam bik lo a, chutih laiin compression set-ah chuan temperature sang (175°C)-ah chuan EPDM adhesives-a Mooney viscosities sang zawk tan danglamna engemaw zat a awm thung.
10. Thutawp .
Ethylene leh diolefin awm zat hian temperature hniam taka hmanna hmuna EPDM elastomers te hnathawh danah nghawng lian tak a nei a, ethylene content hniam tak nei polymer te chuan an thawk tha a, polymer ethylene portion tihbuai avangin diolefin content sang tak nei polymer te pawh an tha chho hle. Low ethylene content polymer hi temperature hniam performance a tihkhawtlai a nih chuan hman tur a ni.
