Yam khoom muaj polypropylene muaj
Vim muaj cov polypropylene muaj cov qib siab ntawm stereoscopic regularization, nws muaj crystallinity zoo, thiab nws cov crystallinity feem ntau yog 50-70%, qee zaus txog li 80% .Cov siab dua qhov isometric degree, zoo dua cov crystallinity thiab qhov ntau dua qhov ntom ntub.Kom ntom ntawm polypropylene feem ntau yog 0.90 ~ 0.91g / cm3.Polypropylene muaj ntau cov crystalline daim ntawv.Qhov kev mob ntawm crystallization (xws li cov txheej txheem cua txias) sib txawv, ua cov ntaub ntawv sib txawv ntawm cov ntxhuav ua ntej, yog li cuam tshuam rau lub hardness, rigidity, qhov muaj zog thiab qhov kaj. yog li 164 ~ 170 ℃, melting point of polypropylene thiab polyethylene, muaj cua kub zoo, thiab nws cov khoom tuaj yeem siab tshaj 100 ℃, tsis tshua muaj peev xwm yuav siv hauv 110 ℃ nruam thiab siv sib xyaw ntsuas kub txog 120 ℃, 150 ℃, tab sis vim pp molecular saw methyl nyob ua ke, cov polyethylene molecular saw rigidity, siab iav hloov qhov kub (- 10 ℃ los yog li ntawd) txias resi stance yog poorer, kub kub embrittlement.Tag nrho ua ke tsawg kub uas siv cov kev txwv kub ntawm polypropylene feem ntau - 20 ℃ mus rau 15 ℃. Nyob ze ze 0 ℃, polypropylene me ntsis ntawm crisp. Polypropylene tensile zog, yield zog, rigidity, hardness yog siab dua polyethylene.Nws molecular hnyav ntxiv (cov qauv ntawm cov tawv nqaij txo), lub zog tensile thiab elongation nce, tab sis raws li qhov tsis haum molecular hnyav, cov crystallization slows down, yield lub zog, rigidity thiab hardness yau me ntsis.Lub siab dua cov isotropy ntawm polypropylene, lub siab dua yielding, rigidity thiab hardness yuav tsum.Qhov lub zog lub zog ntawm polypropylene tsawg tsawg, tshwj xeeb tshaj yog thaum tus molecular luj yog tsawg thiab cov isoparametric degree siab.Cov kom txhim kho tej yam kuj ua thiab kom txo tau cov kev kub hnyiab , copolymerized polypropylene (feem ntau yog ua los ntawm copolymerization ntawm propylene nrog me me ntawm ethylene) yuav siv, los yog txoj kev ntawm cov kev hloov kho blending yuav siv tau rau toughen polypropylene.Qhov mechanical zog ntawm polypropylene yog characterized zoo flexural qaug zog, tshwj xeeb tshaj yog cov oriented polypropylene, uas muaj peev xwm ntau ntau tshaj li ib lab bends.Yog siv no feature, peb yuav tsim ib lub npov nkaus pob khawm nrog qab hau.Electrical cov khoom ntawm polypropylene thiab polyethylene zoo sib xws, nrog hluav taws xob zoo hluav taws xob, ntim resistivity Ω. > 1016 cm, dielectric qhov (2.2 ~ 2.6) thiab dielectric poob (0.0004 ~ 0.001) tsawg heev, thiab cuam tshuam los ntawm qhov tsawg ntawm me me.Qhov yooj yim tshuaj lom neeg ntawm polypropylene yog zoo li polyethylene thiab ruaj khov rau feem ntau cov xov xwm. alkali los yog ntsev dlaws, ntxiv rau qhov oxidation ntawm rendering, nyob rau hauv 100 ℃ rau PP yuav luag tsis muaj kev puas tsuaj.Los kua dissolves polypropylene thaum sov chav tsev.Thaum kub nce, qee cov kua, xws li aromatics thiab chlorinated hydrocarbons, polypropylene.Thaum 80 ℃, polypropylene tau yaj hauv aromatics thiab chlorinated hydrocarbons, xws li xylene, decalin, carbon tetrachloride, thiab lwm yam.Thaum ntawm kev hloov ntawm cov kab mob tertiary ntawm lub ntsiab saw ntawm polypropylene, polypropylene yog sensitive pa thiab yog nws sov oxygen kev laus thiab photochygen kev laus. Kev laus zuj zus yog ceev npaum li polyethylene.Copper ions muaj cov nyhuv catalytic rau cov laus ntawm polypropylene.Yog li, rau cov khoom polypropylene uas tau raug kub kub ntev los yog siv sab nraum zoov, anti-laus system nyob rau hauv lub faib. Nyob rau hauv cov ntaub ntawv ntawm hluav taws xob rwb thaiv tsev ntawm tooj liab hu, tooj liab inhibitor yuav tsum tau ntxiv los yog tooj liab-ua polypropylene resin nrog toojper inhibitor yuav tsum tau xaiv.The polarities ntawm polypropylene yog tsis-polymer, thiab nws cov dej txaus tus nqi yog tsawg heev. Feem ntau, nws tsis tas yuav qhuav los ua ntej txoj kev ua tiav. Thaum tsim nyog, nws yuav tsum nyob rau hauv 80 ~ 100 ℃ drying 3 ~ 4 teev. Lub qhov cub ua kom sov yog 210 ~ 250 ℃ .Tau siab kub los yog lub sijhawm sov so ntev, txo obviously vim thermal degradation, ua rau cov neeg ploj tsis zoo.Qhov kev peev xwm ntawm polypropylene hloov zoo heev nyob rau hauv txoj kev ua cov txheej txheem ntawm thermal shrinkage thiab crystallization.Rau cov tshuaj molding khoom, npuas thiab indentations yog ib qho yooj yim uas yuav ua nyob rau hauv lub thawv qhov, reinforcing tuav , cov chaw nyob ze thiab cov cheeb tsam uas muaj cov phab ntsa loj nyob rau hauv. Qee qhov chaw muaj qhov siab tshaj plaws, nws yog qhov zoo uas yuav tsum tau xaiv hloov qis tsawg polypropylene.Polypropylene yaj crystallization nyob rau hauv lub cev ua hauj lwm yuav txo cov najlub najlei vim qeeb nucleation ntawm lub siab , yog li ntawd nws yog ib qho yooj yim kom tsim spherulites loj loj, uas ua rau muaj zog feem thiab tsis pluag transparency.Ntawm ntxiv ntawm zoo crystalline nu cleating tus neeg sawv cev yuav ua rau kom cov naj npawb siv lead ua, ua kom zoo dua qhov siv lead ua, ua kom lub zog zoo dua thiab txhim kho cov ntawv pom zoo.Qhov ntxiv, uas ua polypropylene pob tshab, tau tau commercialized nyob rau hauv xyoo tsis ntev los no.Thaum dhau los ntawm nucleating tus neeg sawv cev, qhov loj ntawm lub spherulites tsis tshua muaj kev cuam tshuam los ntawm qhov kub thiab txias, uas tuaj yeem txo cov cwj pwm tsis sib xws los ntawm qhov tsis sib npaug ntawm cov khoom siv sib txig sib npaug ntawm qhov tsis sib npaug.Thaum dhau los, tom qab ntxiv tus neeg sawv cev nucleating, tus nqi siab tshaj ntawm crystallization kub mus rau 140 ℃ (feem ntau polypropylene crystallization tus nqi ntawm 120 ~ 130 ℃), qhov ceev yog ceev nrawm, crystallinity nce, txo cov crystallization thiab shrinkage deformation ntawm molding khoom.