UBUCIKO
UBUHLE NEMPILO
UBUCIKO BEZANDLA
AMASIKO NOMLANDO
EZOKUZIJABULISA
IMVELO
UKUDLA NEZIPHUZO
REVERSE ENGINEERING
IZAYENSI
EZEMIDLALO
UBUCHWEPHESHE
IZINTO EZIGQOKWAYO
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.
Osezingeni eliphezulu
Hours per batch (industrial)
Imiyalelo
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.
Izinto zokwakha zalesi sinyathelo:
Amanzi Acwengisisiwe1 as required
I-powder ye-polyvinyl alcohol1 as requiredAmathuluzi adingekayo:
I-reactor yokwenza i-polymer enejakhethi2
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.
Izinto zokwakha zalesi sinyathelo:
I-monomer ye-vinyl acetate1 as required
I-initiator ye-persulfate1 as requiredAmathuluzi adingekayo:
I-reactor yokwenza i-polymer enejakhethi3
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.
Amathuluzi adingekayo:
I-reactor yokwenza i-polymer enejakhethi4
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.
Amathuluzi adingekayo:
I-reactor yokwenza i-polymer enejakhethiIzinto
4- 1 as requiredIsibambeli
- 1 as requiredIsibambeli
- 1 as requiredIsibambeli
- 1 as requiredIsibambeli
Le blueprint yenza
Ama-blueprint ahlobene
Lama-blueprint abelana ngolwazi — amasu, izinto noma izimiso
CC0 Isizinda Somphakathi
Le blueprint ikhishwe ngaphansi kwe-CC0. Ukhululekile ukukopisha, ukuguqula, ukusabalalisa, nokusebenzisa ngaphandle kwemvume.
Sekela uMenzi ngokuthenga imikhiqizo nge-Blueprint yabo IKhomishane Yomenzi kumiswe ngabathengisi, noma dala inguqulo entsha yale Blueprint bese uyifaka njengoxhumaniso ku-Blueprint yakho ukuze wabelane ngemali engenayo.