Lub sijhawm kub kub rau kev sib xyaw ntawm polyvinyl cawv (PVA) thiab dej nyob ntawm qhov piv ntawm cov khoom. Feem ntau, thaum qhov piv ntawm PVA rau dej yog 1: 1, lub sijhawm boiling yog 30 feeb.
Cov txheej txheem rau boiling PVA- dej sib tov yog raws li nram no:
1. Ua ntej, sib tov cov PVA thiab dej ua ke hauv qhov sib piv 1: 1.
2. Tom ntej no, muab cov sib tov tso rau hauv lub lauj kaub thiab ua kom sov tshaj qhov nruab nrab kub kom txog thaum nws nce mus txog qhov kub.
3. Thaum boiling, yaug qhov sib tov nrog dej sov kom tshem tawm tej impurities.
4. Thaum kawg, hloov cov sib tov rau hauv ib lub thawv thiab tsau rau hauv dej sov, tswj cov txheej txheem boiling rau 30 feeb.
Lub hauv paus ntsiab lus tom qab boiling ib PVA - dej sib tov yog raws li nram no: Polyvinyl cawv yog ib tug polar molecule uas muaj peev xwm tsim tsis muaj zog hydrogen bonds nrog dej molecules. Thaum sib tov yog rhuab mus rau ib tug tej yam kub, cov hydrogen bonds raug cuam tshuam, ua rau cov sib tov rau boil.