Styrene Butadiene Roj Hmab

Styrene-butadiene lossis styrene-butadiene roj hmab (SBR) piav txog cov tsev neeg ntawm cov roj hmab hluavtaws muab tau los ntawm styrene thiab butadiene (tus qauv tsim los ntawm Goodyear hu ua Neolite. Cov ntaub ntawv no muaj kev puas tsuaj zoo thiab kev laus zoo thaum muaj kev tiv thaiv los ntawm cov khoom ntxiv. Hauv xyoo 2012, ntau dua. Ntau tshaj 5.4 lab tonnes ntawm SBR tau ua tiav thoob ntiaj teb Kwv yees li 50% ntawm lub tsheb log tsheb yog tsim los ntawm ntau hom SBR Cov styrene / butadiene piv cuam tshuam rau cov khoom ntawm cov khoom siv polymer: nrog cov ntsiab lus siab styrene, cov roj hmab muaj zog thiab tsawg dua SBR Nws tsis yog yuav tsum tsis meej pem nrog cov thermoplastic elastomer, styrene-butadiene thaiv copolymer, txawm tias tau muab los ntawm tib lub monomers.
Hom ntawm SBR
SBR yog muab los ntawm ob monomers, styrene thiab butadiene. Kev sib xyaw ntawm ob lub monomers yog polymerized los ntawm ob txheej txheem: los ntawm kev daws (S-SBR) lossis ua ib qho emulsion (E-SBR). E-SBR tau siv ntau dua.
Emulsion polymerization
E-SBR tsim los ntawm emulsion polymerization yog pib los ntawm cov dawb radicals. Cov hlab ntsha tshwm sim feem ntau raug them nrog ob lub monomers, lub tshuab hluav taws xob dawb radical, thiab cov saw hlau hloov pauv xws li alkyl mercaptan. Radical pib muaj xws li potassium persulfate thiab hydroperoxides ua ke nrog ferrous ntsev. Emulsifying agents muaj ntau yam xab npum. Los ntawm "capping" cov organic radicals loj hlob, mercaptans (xws li dodecylthiol), tswj qhov hnyav molecular ntawm cov khoom. Feem ntau, polymerizations raug tso cai rau mus rau ca. 70%, ib txoj kev hu ua "short stopping". Nyob rau hauv txoj kev no, ntau yam additives yuav raug tshem tawm ntawm lub polymer.
Kev daws teeb meem polymerization
Solution-SBR yog tsim los ntawm cov txheej txheem anionic polymerization. Polymerization yog pib los ntawm alkyl lithium compounds. Dej thiab oxygen tsis suav nrog. Cov txheej txheem yog homogeneous (tag nrho cov Cheebtsam yog yaj), uas muab ntau dua kev tswj ntawm cov txheej txheem, cia tailoring ntawm lub polymer. Lub organolithium compound ntxiv rau ib qho ntawm cov monomers, tsim cov carbanion uas tom qab ntawd ntxiv rau lwm cov monomer, thiab lwm yam. Rau kev tsim cov log tsheb, S-SBR tau txais txiaj ntsig ntau dua vim tias nws muaj kev txhim kho ntub dej thiab txo qis kev ua haujlwm, uas txhais tau tias muaj kev nyab xeeb ntau dua thiab kev lag luam roj zoo dua, raws li kev ua haujlwm ntawm lub log tsheb.