UBUHANZI
UBWIZA N'UBUZIMA
UBUKORIKORI
UMUCO N'AMATEKA
IMYIDAGADURO
IBIDUKIKIJE
IBIRIBWA N'IBINYOBWA
UBWUBATSI BUSUBIRA INYUMA
UBUMENYI
SIPORO
IKORANABUHANGA
IBYAMBARWA
PVA Wood Glue by Emulsion Polymerisation
White wood glue is polyvinyl acetate (PVAc) dispersed in water. It is made by emulsion polymerisation: vinyl acetate monomer is stirred into water with a stabiliser, here polyvinyl alcohol, and a water-soluble initiator such as a persulfate, which splits into radicals above about 50 °C and starts chains that link the monomer into polymer. The water carries away the heat, so the reaction stays under control. More monomer is usually fed in slowly as the particles grow. What comes out is a milky dispersion, and for glue that dispersion is the product. Vinyl acetate itself is made from ethylene, acetic acid and oxygen over a palladium catalyst.
Hejuru
Hours per batch (industrial)
Amabwiriza
1
1
Charge the reactor
Charge the reactor
Fill the jacketed reactor with water and dissolve the polyvinyl alcohol, which keeps the polymer particles from clumping.
Ibikoresho by'iyi ntambwe:
Amazi Yatunganyijwe1 as required
Ifu ya polyvinyl alcohol1 as requiredIbikoresho bikenewe:
Igikoresho cyo gukora polymère gifite ikoti2
2
Heat and start
Heat and start
Warm the water to above about 50 °C, add part of the monomer and the persulfate initiator; the initiator splits into radicals and polymerisation begins.
Ibikoresho by'iyi ntambwe:
Monomère ya vinyl acetate1 as required
Igitangiza cya persulfate1 as requiredIbikoresho bikenewe:
Igikoresho cyo gukora polymère gifite ikoti3
3
Feed and hold
Feed and hold
Feed the rest of the monomer in slowly while stirring; the jacket removes the heat of reaction so the temperature stays steady.
Ibikoresho bikenewe:
Igikoresho cyo gukora polymère gifite ikoti4
4
Finish
Finish
When the monomer is used up, cool the milky dispersion. It is used as it is: as wood glue, white or yellow carpenter's glue.
Ibikoresho bikenewe:
Igikoresho cyo gukora polymère gifite ikotiIbikoresho
4- 1 as requiredUmwanya
- 1 as requiredUmwanya
- 1 as requiredUmwanya
- 1 as requiredUmwanya
Iki gishushanyo gikora
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