Txheej txheem cej luam ntawm PVC cob
Polyvinyl chloride (PVC) yog ib qho ntawm cov khoom lag luam ntxov tshaj plaws nyob hauv lub ntiaj teb, PVC yas yog ib qho ntawm tsib lub hom phiaj tseem ceeb ntawm cov khoom siv hluavtaws. Tam sim no nws yog lub ntiaj teb thib ob hom yas loj tshaj plaws tom qab polyethylene, suav txog 29 feem pua ntawm lub ntiaj teb tag nrho cov khoom siv hluavtaws. Txij li xyoo 2004, nws cov khoom siv hauv tsev tau tshaj li ntawm polyethylene thiab polypropylene, dhia mus rau thawj qhov chaw, thiab kev loj hlob sai.
PVC resin yog cov hmoov dawb los yog cov khoom, particle loj 60 ~ 250μm, pom meej ntom 0.40 ~ 0.60g/cm3, ntom ntawm 1.35 ~ 1.45 g/cm3, refractive index ntawm 1.544 (20 degree), dej nqus tsawg dua lossis sib npaug li 0.5 feem pua. Insoluble hauv dej, cawv, roj av, tuaj yeem yaj lossis yaj hauv ether, ketone, chlorinated aliphatic hydrocarbons thiab muaj ntxhiab hydrocarbons. Muaj zog acid kuj nyob rau hauv chav tsev kub, resistant rau tej concentration ntawm hydrochloric acid, sulfuric acid hauv qab no 90 feem pua, 50 feem pua rau 60 feem pua ntawm nitric acid thiab caustic soda daws hauv qab 20 feem pua, ruaj khov rau ntsev. Nws tuaj yeem hlawv ntawm nplaim taws thiab tua thaum nws tawm ntawm cov nplaim taws. Zoo dielectric rwb thaiv tsev.
PVC resin yog ua los ntawm 200 ~ 500nm thawj cov khoom (tseem hu ua cov qauv hauv cheeb tsam) sib sau ua ke rau hauv 1 ~ 2µm thawj cov khoom (tseem hu ua cov khoom nruab nrab), thiab tom qab ntawd sib sau los ntawm thawj cov khoom rau hauv 50 ~ 250µm resin particles.The crystallinity ntawm PVC yog hais txog. 5 ~ 10 feem pua , thiab cov qauv txiav txim feem ntau muaj nyob hauv nruab nrab ntawm cov qauv hauv cheeb tsam.
PVC cob yog non-crystalline, polar polymer, thermoplastic. Nws cov iav hloov pauv kub yog 75 ~ 105 degree nyob ntawm qhov hnyav molecular. Nws cov softening kub thiab melting kub yog siab, ntshiab PVC cob yuav plasticized thiab ua tiav tsuas yog thaum nws yog feem ntau 160 mus rau 210 degree, vim lub ncov qaumteb qabte daim ntawv cog lus ntawm cov macromolecules thiaj li hais tias PVC qhia nyuaj thiab nkig zog. Ntxiv mus, PVC molecules muaj cov tshuaj chlorine, thaum kub txog 120 degree, ntshiab PVC uas yog pib ntawm dehydrogen chloride cov tshuaj tiv thaiv, uas yuav ua rau thermal degradation ntawm PVC. Yog li ntawd, nyob rau hauv kev ua yuav tsum tau ntxiv rau stabilizers, plasticizers thiab lwm yam additives, hloov mus ua ntau yam ntawm PVC khoom.
PVC cov khoom nyob ntawm seb cov ntsiab lus ntawm cov yas yas tuaj yeem muab faib ua cov khoom muag thiab tawv, cov ntsiab lus ntawm cov yas yas ntawm 0 mus rau 5 qhov chaw rau cov khoom tawv, 5 mus rau 25 qhov chaw rau cov khoom ib nrab, ntau tshaj 25 qhov chaw rau cov khoom muag muag.
PVC yas siv tau rau extrusion, txhaj tshuaj molding, calendering, compression molding thiab tshuab moulding thiab lwm yam kev ua. Txawm li cas los xij, thaum ua tiav, yuav tsum tau ua ntej kneaded, kom ntau yam additives thiab PVC resin ntawm 90 ~ 110 degree sib tov sib npaug. Piv nrog rau lwm cov khoom siv dav dav, cov qauv kev ua haujlwm thiab kev siv tshuab ua haujlwm yog qhov nyuaj.
PVC yas muaj lub cev zoo thiab cov khoom siv kho tshuab, tuaj yeem siv rau kev tsim cov khoom siv hauv tsev, cov khoom ntim, cov khoom siv hluav taws xob, cov khoom siv, thiab lwm yam, dav siv hauv kev lag luam, kev ua liaj ua teb, kev tsim kho, kev thauj mus los, hluav taws xob thiab kev sib txuas lus thiab ntim khoom thiab lwm yam. . Tuam Tshoj tus PVC noj yog tsuas yog muab faib ua ob qhov loj, ib qho yog cov khoom muag muag, feem ntau suav nrog cov xov hlau thiab cables, ntau lub hom phiaj ntawm cov yeeb yaj kiab, cov ntaub ntawv paving, ntaub txheej, tawv tawv, ntau hom hoses, hnab looj tes, cov khoom ua si, khau yas, xws li nrog rau qee qhov tshwj xeeb coatings thiab sealants. Qhov thib ob yog cov khoom tsis sib xws, feem ntau suav nrog ntau yam profiles, raj, daim hlau, cov nplooj ntawv nyuaj, lub raj mis thiab cov thawv hollow.
