Aramid fiber yog cov ntawv luv ntawm aromatic polyamide fiber, muaj ob pawg tseem ceeb: ib qho yog polyterephthalyl-p-phenylenediamine (PPDA) fiber, xws li Kevlar-49 ntawm DuPont ntawm Tebchaws Meskas, TwaronHM ntawm Enka Tuam Txhab ntawm Netherlands , aramid 1414 ntawm Tuam Tshoj, thiab lwm yam.; Lwm hom yog polyparabenamide (PBA) fibers, xws li Kevlar-29, aramid 14, thiab lwm yam. Kevlar-49 yog cov organic fiber ntau tsim los ntawm DuPont nyob rau hauv lub lig 60s ntawm lub xyoo pua 20th thiab ua lag luam nyob rau hauv lub 70s. ntawm lub xyoo pua 20th. Qhov no yog ib yam tshiab ntawm cov khoom siv zoo heev xws li lub zog siab, siab modulus, kub tsis kam thiab tsis tshua muaj siab. Kevlar{11}} fiber ntau yog siv rau hauv cov khoom sib xyaw xws li aviation, aerospace, shipbuilding, khoom siv kho mob thiab cov khoom ua si. Vim nws qhov kev ua tau zoo heev thiab qhov tshwj xeeb ntawm daim ntawv thov ntau yam, daim ntawv thov daim teb yuav txuas ntxiv mus.
Cov khoom ntawm aramid fibers txawv ntawm lwm cov organic fibers nyob rau hauv uas lawv tensile zog thiab thawj modulus yog siab, thaum lawv elongation yog tsawg. Aramid fiber ntau muaj cov khoom zoo heev hauv cov organic fibers. Cov saw hlau molecular ntawm aramid yog tsim los ntawm benzene rings thiab amide pawg tau teem rau hauv ib txoj cai lij choj. Txoj hauj lwm ntawm cov pab pawg amide yog nyob rau hauv txoj hauj lwm ncaj nraim ntawm lub nplhaib benzene, yog li cov polymer no muaj kev ua haujlwm zoo, ua rau muaj qhov siab ntawm crystallinity ntawm aramid fibers. Cov saw hlau agglomerated molecular no nruj heev taw qhia nyob rau hauv fiber ntau axial kev taw qhia, thiab cov hydrogen atoms ntawm cov molecular saw yuav ua ke nrog carbonyl pawg ntawm amide khub ntawm lwm cov molecular saw los tsim hydrogen bonds, ua ib tug transverse link ntawm polymer molecules.
Nws tseem tuaj yeem pom tau tias Kevlar-49 thiab aramid 1414 cov khoom sib xyaw muaj qhov zoo ntawm cov iav fiber reinforced composites ntawm qhov ntom thiab lub zog. Tsis tas li ntawd, thaum Kevlar -49 thiab aramid 1414 unidirectional composites raug sim nyob rau hauv qhov nro, qhov kev ntxhov siab-strain nkhaus tau txais ua ntej tawg yog ib txoj kab ncaj nraim, tab sis nyob rau hauv qhov kev ntsuam xyuas compression, lawv yog elastic nyob rau hauv tsis tshua muaj kev nyuaj siab thiab yas nyob rau hauv high stress. , Kevlar-49 thiab aramid 1414 cov ntaub ntawv sib xyaw Cov cuab yeej tshwj xeeb compression no zoo ib yam li cov tawv tawv ntawm cov hlau thiab muaj qee qhov tseem ceeb hauv kev ua haujlwm tshwj xeeb.
Aramid fibers thiab lwm cov organic fibers, zoo li iav fibers, tau yooj yim woven rau hauv ntau yam ntaub. Kev siv cov ntaub no coj tau yooj yim rau cov txheej txheem molding, thiab aramid staple fibers feem ntau yog siv los ntxiv dag zog rau cov thermoplastic composites los txhim kho lub zog tawg ntawm cov thermoplastic composites. Staple fiber reinforced thermoplastic composites, feem ntau yog los ntawm rub cov staple fibers los ntawm cov khoom siv matrix. Thaum cov ntsiab lus fiber ntau me me, cov khoom siv hluav taws xob tuaj yeem ua rau hauv cov khoom sib txuas. Raws li cov ntsiab lus fiber ntau nce, qhov toughness ntawm cov khoom sib xyaw nce. Raws li cov ntaub ntawv tshaj tawm, thaum cov khoom siv matrix muaj 20% aramid fiber ntau, nws tuaj yeem txhim kho cov khoom siv ntawm cov khoom sib xyaw.
Aramid composites muaj cov khoom tsis zoo compressive, txog ib nrab ntawm cov iav fiber ntau. Yog tias lwm cov fiber ntau ntxiv los ua ib qho kev sib xyaw ua ke, nws cov compressive kuj tuaj yeem txhim kho tau zoo. Vim hais tias cov coefficient ntawm thermal expansion ntawm aramid fibers thiab carbon fibers yog ze heev, cov ob fibers yog tshwj xeeb tshaj yog haum rau tov siv nyob rau hauv sib txawv proportions. Cov ntaub ntawv sib xyaw ua ke nrog aramid thiab graphite tuaj yeem kov yeej cov teeb meem tseem ceeb ntawm tus nqi siab ntawm graphite composites thiab qhov tawg tam sim ntawd vim tsis muaj zog. Aramid yog sib xyaw nrog iav fiber ntau, uas tuaj yeem kov yeej qhov tsis zoo ntawm qhov tsis zoo ntawm cov iav fiber ntau. Thaum ntsib kev siv tshwj xeeb, muaj ntau txoj hauv kev sib xyaw thiab siv cov ntaub ntawv sib xyaw, uas tuaj yeem ua kom haum raws li kev xav tau ntawm kev siv.
Tsis tas li ntawd, kev sib xyaw ntawm aramid thiab carbon, boron thiab lwm cov high-modulus fibers tuaj yeem tau txais lub zog compressive xav tau rau daim ntawv thov qauv, thiab nws cov khoom tshwj xeeb yog qhov sib piv nrog lwm cov khoom siv fiber ntau. Piv txwv li, cov khoom siv hybrid uas muaj 50% aramid fiber ntau thiab 50% siab zog carbon fiber nrog epoxy resin muaj lub zog khoov ntau dua 620MPa. Qhov cuam tshuam lub zog ntawm cov khoom sib xyaw tom qab sib xyaw yog kwv yees li ob zaug ntawm cov pa roj carbon fiber ntau ib leeg, thiab yog tias cov khoom siv high-modulus graphite sib xyaw, qhov cuam tshuam lub zog yuav zoo dua.