Kev txiav txim siab cov ntsiab lus ntawm polycarbonate diols feem ntau yog tsom rau kev soj ntsuam cov khoom purity thiab muaj pes tsawg leeg, yog li muab cov khoom siv raw khoom tsis zoo rau cov khoom siv polyurethane tom ntej. Raws li polycarbonate diols yog cov polymers tshwj xeeb los ntawm kev faib tawm qhov hnyav ntawm molecular, lawv feem ntau tsis tuaj yeem txiav txim siab ncaj qha los ntawm qhov hnyav yooj yim lossis titration, tsis zoo li qis -molecular- hnyav compounds. Yog li ntawd, kev soj ntsuam cov tswv yim suav nrog kev ntsuam xyuas tag nrho ntawm cov khoom muaj pes tsawg leeg thiab kev ua tau zoo raws li cov yam ntxwv ntawm cov qauv thiab cov kev xav tau ntawm kev siv, siv cov ntsuas xws li tus nqi hydroxyl, qhov hnyav molecular, noo noo cov ntsiab lus, thiab cov kua qaub. Ntawm cov no, tus nqi hydroxyl yog qhov tseem ceeb ntawm qhov ntsuas; los ntawm kev ntsuas cov ntsiab lus hydroxyl ib chav tsev loj ntawm cov qauv, nws tsis ncaj qha cuam tshuam qhov nruab nrab molecular hnyav thiab reactivity ntawm polycarbonate diol.
Kev txiav txim siab tus nqi Hydroxyl feem ntau siv tshuaj titration. Cov txheej txheem no suav nrog kev cuam tshuam cov pawg hydroxyl hauv cov qauv nrog cov reagents tshwj xeeb, ntsuas cov reagent noj ntawm titration, thiab xam cov nqi hydroxyl los ntawm cov txiaj ntsig. Cov txheej txheem yuav tsum tau ntsuas tus qauv kom raug thiab nruj me ntsis tswj cov tshuaj tiv thaiv kom ntseeg tau tias cov tshuaj tiv thaiv ua tiav. Tom qab ntawd, titration yog ua nrog rau ib qho kev xeem dawb paug rau lub hom phiaj calibration. Tus nqi hydroxyl ntawm polycarbonate diol yog xam raws li tus qauv loj, titrant concentration, thiab qhov sib txawv ntawm titrant ntim ntawm cov qauv thiab qhov kev kuaj dawb paug. Rau cov khoom uas muaj qhov zoo-txhais cov qauv thiab qhov hnyav molecular, qhov nruab nrab molecular hnyav thiab muaj pes tsawg leeg tuaj yeem txheeb xyuas ntxiv los ntawm kev sib piv theoretical hydroxyl qhov tseem ceeb nrog rau kev sim.
Ntxiv nrog rau kev txiav txim siab tus nqi hydroxyl, cov txheej txheem ntxiv cov yam ntxwv- xws li ¹H-NMR (proton nuclear magnetic resonance) spectroscopy, infrared (IR) spectroscopy, thiab gel permeation chromatography (GPC)- tuaj yeem ua haujlwm. IR spectroscopy lees paub cov qauv tshuaj los ntawm kev txheeb xyuas cov yam ntxwv ntawm kev nqus cov peaks txuam nrog carbonate thiab hydroxyl pawg; GPC txiav txim tus lej- qhov nruab nrab qhov hnyav molecular, qhov hnyav- nruab nrab qhov hnyav molecular, thiab qhov hnyav molecular faib; thiab NMR spectroscopy enables cov ncauj lus kom ntxaws tsom xam ntawm molecular saw lug thiab cov proportions ntawm ntau yam structural units. Hauv kev tswj xyuas qhov ua tau zoo, kev sib xyaw ntawm cov tshuaj lom neeg thiab ntsuas ntsuas feem ntau yog siv los muab kev ntsuam xyuas dav dav ntawm polycarbonate diol cov ntsiab lus thiab cov khoom zoo.