Aj. Dong et al., Structure-property relationships of core-shell type waterborne polyacrylate-polyurethane microemulsions, MACRO CH P, 199(12), 1998, pp. 2635-2640
Different cross-linking types of core-shell type waterborne polyacrylate-po
lyurethane (PACPU) microemulsions, in which polyurethane acts as the shell
of the latex particles and a copolymer of acrylate monomers as the core, we
re synthesized. In the anionic polyurethane film, there is a certain degree
of soft-hard phase mixing and different extents of short-range order of th
e hard segments. The introduction of a polyacrylate core increases the soft
-hard phase separation in the polyurethane and breaks the short-range order
of the hard segments in polyurethane to some extent. The hard segments in
the shell and the core cause a widened tan delta peak. This peak shifts to
higher frequencies as the core-shell ratio increases and also when a Type A
or Type B cross-linking structures exist. The cross-linking structure, esp
ecially Type B, improves the soft-hard separation and the phase mixing of t
he core and the hard segments in the shell and at the same time breaks the
short-range order in the hard segments. The cross-linking structure does no
t affect the thermogravimetric properties of the PAC-PU films.