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Unexpected Crosslinking During Acetoacetoxy Group Protection on Waterborne Crosslinkable Latexes
Author(s) -
González Iñigo,
Arzamendi Gurutze,
Asua José M.,
Leiza José R.
Publication year - 2006
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200600235
Subject(s) - copolymer , materials science , polymer chemistry , hydrolysis , emulsion , polymer , organic chemistry , chemistry , composite material
Summary: The microstructure of the polymer synthesized by seeded semicontinuous emulsion copolymerization of AAEMA was investigated. It was found that the neutralization of the latexes with ammonia to protect acetoacetoxy functionality against hydrolysis during storage had a remarkable effect on the gel content. A base catalyzed Michael addition reaction between acetoacetoxy groups and terminal double bond (TDB) is proposed as responsible for the chain precrosslinking observed. The presence of TDB in the latexes was demonstrated by means of 1 H NMR. Moreover, the chain precrosslinking affected the subsequent crosslinking reaction of the latex with diamines hindering chain interdiffusion and yielding poorer mechanical properties.Michael addition between AcAc functional groups and TDB, and final gel content of the MMA/BA/MAA latexes with different amounts of AAEMA.