Raws li ib qho ntawm tsib yam tseem ceeb - lub hom phiaj engineering plastics, polycarbonate (PC) yog dav siv nyob rau hauv electronics, automotive manufacturing, thiab optical instruments vim nws siab transparency, zoo heev tej yam kev mob, thiab seem stability. Lub hauv paus ntawm nws cov txiaj ntsig kev ua tau zoo yog nyob rau hauv nws cov qauv molecular tshwj xeeb thiab cov nyhuv synergistic ntawm nws cov khoom tseem ceeb.
Lub hauv paus tseem ceeb ntawm PC yog lub siab molecular polymer synthesized los ntawm bisphenol A (BPA) thiab phosgene los yog diphenyl carbonate (DPC) los ntawm cov tshuaj tiv thaiv polycondensation. BPA yog qhov yooj yim monomer uas tsim cov pob txha molecular. Nws ob pawg phenolic hydroxyl tsim alternating linear segments nrog carbonate pawg, muab cov khoom rigidity thiab kub tsis kam. Lub xub ntiag ntawm carbonate bonds (-O-CO-O-) sib npaug rigidity los ntawm kev hloov pauv ntawm cov saw hlau molecular, muab PC ob qho tib si hardness thiab toughness. Qhov no "rigid- hloov tau" molecular tsim yog nws cov yam ntxwv tseem ceeb uas txawv nws ntawm cov yas zoo tib yam.
Los ntawm cov txheej txheem hluavtaws, txoj hauv kev tseem ceeb tau muab faib ua phosgene thiab tsis yog -phosgene txoj kev. Cov txheej txheem phosgene ib txwm siv cov tshuaj phosgene uas muaj kuab lom heev los ua cov khoom siv raw, ua cov khoom siab tshaj -purity tab sis ua rau muaj kev pheej hmoo ntawm ib puag ncig. Txoj kev tsis yog -phosgene siv cov tshuaj ntsuab xws li dimethyl carbonate los hloov phosgene, npaj cov khoom los ntawm transesterification, uas yog ntau nyob rau hauv txoj kab nrog kev txhim kho kom ruaj khov. Qhov sib txawv tseem ceeb ntawm ob txheej txheem yog nyob rau hauv kev tswj ntawm byproducts thiab kev nyab xeeb, tab sis lub ntsiab ntawm cov khoom kawg yog polycarbonate homopolymer los yog copolymer (xws li blended hloov nrog ABS los yog polyester).
Nws yuav tsum raug sau tseg tias PC feem ntau muaj cov lej ntawm cov khoom ntxiv los txhim kho kev ua haujlwm zoo lossis kev ua haujlwm zoo. Piv txwv li, cov hluav taws kub stabilizers tuaj yeem tiv thaiv qhov kub ntawm - kub degradation, antioxidants tuaj yeem ncua kev laus, thiab cov nplaim hluav taws tuaj yeem txhim kho hluav taws. Cov additives no feem ntau suav txog tsawg dua 1%, tab sis ua lub luag haujlwm tseem ceeb hauv kev ua haujlwm ntawm cov khoom siv. Nws yog ib qho tsim nyog sau cia tias bisphenol A (BPA), uas yog cov khoom siv tseem ceeb rau PC, tau ua rau muaj kev tsis sib haum xeeb ntawm zaub mov vim nws cov khoom tsiv teb tsaws chaw. Tam sim no, cov zaub mov tiv tauj qib PC tau txo cov khoom seem los ntawm kev txhim kho cov txheej txheem kom ua tau raws li cov kev cai tswj hwm.
Zuag qhia tag nrho, kev ua haujlwm siab ntawm PC stems los ntawm qhov tseeb piv ntawm BPA rau carbonate pawg thiab kev txiav txim ntawm cov saw hlau molecular. Nrog rau kev nce qib ntawm ntsuab synthesis thev naus laus zis, PC tab tom hloov zuj zus mus rau qhov cuam tshuam ib puag ncig qis thiab ntau- ua haujlwm tau zoo thaum tswj hwm nws cov txiaj ntsig tseem ceeb, txuas ntxiv txhim kho nws txoj haujlwm tsis tuaj yeem hloov pauv hauv qhov siab -kawg kev tsim khoom.