Plasticizers nyob rau hauv cov txheej txheem txheej
Cov yas yas yog siv los tswj cov txheej txheem tsim cov yeeb yaj kiab ntawm cov txheej txheem raws li lub cev kom qhuav zaj duab xis tsim cov ntaub ntawv. Tsim kom zoo zaj duab xis yog qhov tseem ceeb kom ua tau raws li qhov xav tau ntawm cov txheej txheem tshwj xeeb xws li cov yeeb yaj kiab qhuav, substrate adhesion, elasticity, ua ke nrog cov qib siab hardness tib lub sijhawm.
Plasticizers ua hauj lwm los ntawm kev txo cov zaj duab xis tsim kub thiab elasticize lub txheej; plasticizers ua hauj lwm los ntawm embedding lawv tus kheej ntawm cov chains ntawm polymers, sib nrug los ntawm lawv sib nrug (nce "dawb ntim"), thiab yog li txo tus iav hloov kub rau lub polymer thiab ua rau nws softer.
Cov molecules nyob rau hauv polymeric zaj duab xis tsim cov ntaub ntawv, xws li nitrocellulose (NC), feem ntau qhia tsis tshua muaj saw mus, piav qhia los ntawm muaj zog molecular kev sib raug zoo (piav qhia los ntawm van der Waals rog) ntawm lub polymer chains. Lub luag haujlwm ntawm plasticizer yog txo lossis tag nrho tiv thaiv kev tsim ntawm cov ntawv cog lus txuas ntxiv. Nyob rau hauv cov ntaub ntawv ntawm hluavtaws polymers no yuav ua tau tiav los ntawm kev sib txuas elasticizing ntu los yog monomers sterically hinder molecular kev sib raug zoo; Cov txheej txheem kev hloov kho tshuaj no yog hu ua "plasticization puab". Rau natural cov khoom lossis cov polymers nyuaj ntawm kev ua haujlwm tsis zoo, qhov kev xaiv yog siv sab nraud plasticizers hauv txheej txheej txheej
Plasticizers cuam tshuam lub cev nrog lub polymer binder molecule, tsis muaj tshuaj lom neeg cov tshuaj tiv thaiv thiab tsim ib homogeneous system. Kev sib cuam tshuam yog ua raws li cov qauv tshwj xeeb ntawm cov yas yas, feem ntau muaj cov polar thiab non-polar moieties, thiab ua rau txo cov iav kub (Tg). Txhawm rau kom muaj kev ua haujlwm siab, lub plasticizer yuav tsum muaj peev xwm nkag mus rau hauv cov resin ntawm zaj duab xis tsim.
Classic plastizers yog cov khoom hnyav molecular, xws li phthalate esters. Txawm li cas los xij, tsis ntev los no cov khoom lag luam phthalate dawb nyiam dua vim tias kev siv phthalate esters raug txwv vim muaj kev txhawj xeeb txog kev nyab xeeb ntawm cov khoom.