Kevlar - yog ib tug hluavtaws fiber, lub scientific lub npe yog "aramid, polyparaphenylene terephthalamide." Nyob rau hauv 1965, nws tsim lub US lub tuam txhab DuPont. Vim nws siab zog (3620 MPa), ib tug tshwj xeeb kev tiv thaiv zog, lub teeb yuag thiab ductility, Kevlar tau lug siv nyob rau hauv ntau yam teb. Qhov no cov ntaub ntawv uas yog tau withstand ntev-lub sij hawm tej yam thiab lwm yam loads, nws tsis yog deformed.
1970-x kev nyab xeeb thiab txhim khu kev qha nyob rau hauv huab mob Kevlar muab coj mus muag ntau lawm. Txawm li cas los, nyob rau hauv thaum pib nws tau tsim rau lub cuab lub zog ntawm lub tsheb log tsheb, nyob rau hauv thiaj li yuav ua rau kom lawv lub dag lub zog thiab txo phaus. Tam sim no ntxiv rau kev vam meej kev xyaum raws li tam fiber optic thiab tooj liab cables los mus tiv thaiv lawv kev sib tawg thiab tensile mixed fabrics - impart kuj mus rau txiav thiab abrasive influences. Nyob rau hauv kev, xws fabrics uas ua los tiv thaiv padding nyob rau hauv cov khaub ncaws ntawm ncaws pob thiab cov tub rog nyiam thiab Kevlar hnab looj tes. Tub rog ntawm ntau lub teb chaws nyob rau hauv lub ntiaj teb no tau txais thiab Kevlar, siv nws txhua yam khoom, yog siv koom nyob rau hauv tub rog cov khoom thiab kev ruaj ntseg cov kev pab cuam. Ib tug prime piv txwv txog tej kev siv yog cov mos txwv ntawv pov thawj vests.
Tag nrho cov khoom yog Kevlar muaj siab thaum tshav kub kub kuj thiab kuj mus acids thiab alkalis. Rau yav tom ntej cov tshuaj yog ntaub hnab looj tes nrog Kevlar: nyob rau hauv tej manufacturing, uas yog txuam nrog lub peevxwm ntawm qhov nqaij ntuag iav los yog daim ntawv hlau, tas mus li kev sib cuag nrog liab-kub khoom (txog li 100 ° C), nyob rau hauv cov zaub mov kev lag luam, mechanical engineering, tsheb thauj mus los ntawm cov iav thiab lwm yam ntawm lawv ua si irreplaceable. Kevlar hnab looj tes cia li tsim los tiv thaiv lub ob txhais tes ntawm kev txiav nyiaj thaum lub sij hawm, rau Piv txwv li, loj tej ntses, nqaij qaib, nqaij, txiv hmab txiv ntoo thiab zaub. Lawv yog cov khaub-ncaws nyias thiab nyiam - nyob rau hauv lawv txhais tes, "ua pa", saj zawg zog txaus kom cov rhiab heev ntawm lub ob txhais tes thiab cia mus ua hauj lwm nrog me me lus, raws li tau zoo raws li muab zoo heev tuav - ntub dej (oiled) thiab qhuav. Cov hnab looj tes yog manufactured tsis muaj ib leeg thiab nyob rau hauv ntau ntau thiab tsawg, yog li txhua leej txhua tus yuav tau txais ib tug yooj yim tshuaj. Kevlar cov hnab looj tes yuav tsum siv tsis tau tsuas yog raws li ib tug dog dig hnab looj tes, tab sis kuj raws li ib tug hauv ob sab phlu, thiab raws li kev. Lawv tsis yuav tsum tau tshwj xeeb kev kho mob. Ntxuav lawv yuav ua tau ntawm 40 ° C nrog ib tug nruab nrab xab npum, thiab qhov yuav tsum tau mus rau qhuav ntawm chav tsev kub. Koj muaj peev xwm coj lawv mus rau hauv lub qhuav rau tsev ntxhua khaub ncaws Yog hais tias koj xav. Tom qab rov siv thiab ntxuav cov hnab looj tes (hnab looj tes) Kevlar khaws lawv cov kev tiv thaiv zog, zoo lawm thiab tsos, thiab yog li lawv lifespan yog loj txaus.
Zoo pov thawj nyob rau hauv ntau yam kev ua Kevlar yog siv nyob rau hauv cov kev ua si. Caij ski, racers, maus taus racers thiab baseball players zoo siab siv Kevlar hnab looj tes. Lawv nruj, tej yam kuj thiab tshav kub tsis kam yuav txo tus naj npawb ntawm kev raug mob los yog txawm tsis txhob rau lawv.
Tab sis Kevlar nrog rau cov undeniable zoo muaj ib co tsis zoo. Thaum sufficiently siab kub (430-480 ° C) nws decomposes, tiam sis thaum ib kub siab tshaj 150 ° C loses nws lub zog. Cov cua kub npaum li cas thiab ntev, ntawm chav kawm, ua si ib tug luag hauj lwm. Yog li, tshaj 70 teev ntawm raug mus rau ib tug kub ntawm txog 250 ° C Kevlar hnab looj tes poob 50% ntawm nws lub zog. Thaum uas tsis muaj kub (-190 ° C), on qhov tsis tooj, lub dag lub zog thiab elasticity yog khaws cia. Tab sis nyob rau hauv lub neej txhua hnub nws yog tsis yooj yim sua kom tsim ib qho chaw uas yuav rhuav lub molecular qauv ntawm Kevlar.