Chap._400008 - lightly crosslinked PB rubber particle +...

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The polybutadiene substrate used is generally prepared in emulsion batch reaction. Water-soluble initiators such as potassium persulfate may be used. The reaction times usually range from 12-24 hours with 70-90% conversion. The residue butadiene monomers are stripped from the PB latexs. The average latex particle size is determined by the emulsifier quantity. In the next step in the emulsion process, styrene and acrylonitrile are grafted into the polybutadiene substrate. The amount of PB substrate used in the graft reaction is determined by the physical properties desired in the final product and usually ranges from 10 to 60wt% of the total polymer.
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Unformatted text preview: lightly crosslinked PB rubber particle + PB-g-SAN graft polymer SAN copolymer SAN SAN PB-(CH 2-CH) -(CH 2-CH) -* I CH 2 =CH CH-CH=CH-CH 2 CH-CH=CH-CH 2 coupling PB latex * * I (CH-CH=CH-CH 2 ) (CH 2-CH=CH-CH 2 ) (x: 70-80% y: 30-20%) y x N C + N C CH 2 =CH The grafted copolymer is formed at the interface between the rubbe particle (dispersed phase) and the free SAN copolymer domain (continuous phase) Graft copolymer Free SAN copolymer Rubber particle Emulsion ABS resins are recovered from latex by coagulation with dilute salt or acid solution. The slurry is then dewatered by filtration and dired in hot air dryers. (b) Suspension Process...
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This note was uploaded on 10/16/2010 for the course MATSE 441 at Pennsylvania State University, University Park.

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