COLLOIDAL DESTABILIZATION - created from Mind Map

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DEFINITION

COACERVATION PROCESS

PHYSICAL MODE

CHEMICAL MODE

important to separate polymer phase from dispersion medium

latex can not be produced witout destabilization

stages

increase the tendency of particles to attach to one another

distict step must occur

particle aggregate together

aggregate particles coalesce with each other to form coagulate

repulsion forces mus be reduced

particle transport must be achieved

DEFINITION

coagulation

gelation

flocculation

the process of destabilization

form loose agglomerates

modes

physical - without addition of chemical

chemical - with addition of chemical

form coagulum

quickly separate the rubber particle

synerisis can occured

fast processing

form fluid flow system to uniform system

form semi rigid gel

phase change

form flocculum

produced smaller particle

no syneresis occur

removal of dispersion medium

mechanical agitation

heating

freezing

by evaporation

reduce the voulume of dispersion medium

reduce average distance between particles

explain about gelation

application

surface coating

adhesive

particle experience higher shear rate

increase collision frequency

latex become unstable

produce floccs

increase frequency of collision

heat sensitive agent added

enhance latex stability

agglomeration and coalescene occur

direct coacervants

heat sensitizibg coacervant

delayed coacervants

acidic subtances

water soluble electrolytes

hydrophobic organic liquid

hydrphilic organic liquid

generate hydrogen ions

involves salt

the chemical is an alcohol

miscible with dispersion medium

zinc amine system

important ammona preserved latex

rapid colloidal destabilization

dissolved in water