Crosslinking of isocyanate functional acrylic latex with telechelic polybutadiene. II. Film formation/crosslinking

✍ Scribed by Jiangtian Xu; Victoria L. Dimonie; E. David Sudol; Olga L. Shaffer; Mohamed S. El-Aasser

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 363 KB
• Volume: 69
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980801)69:5<977::aid-app17>3.0.co;2-l

✦ Synopsis

The mechanism of film formation and crosslinking in a poly(methyl methacrylate/ n-butyl acrylate/TMI) (PMBT) and amino-telechelic polybutadiene (PBD-NH 2 ) latex blend was studied. Films cast from the latex blends were ultramicrotomed and examined by transmission electron microscopy. The PBD-NH 2 was found to be located primarily at the surface of the PMBT particles due to a crosslinking reaction. Without the possibility of crosslinking (when TMI was absent in the acrylic copolymer), the PBD-NH 2 only formed segregated phases in the acrylic polymer matrix due to the incompatibility of the two polymers. While this PBD-NH 2 could be extracted with toluene, the PBD-NH 2 crosslinked at the PMBT particle surfaces was not extractable. FTIR results showed that the isocyanate groups in the PMBT were completely consumed when the PBD-NH 2 concentration was sufficiently high, indicating that the PBD-NH 2 had diffused and reacted inside the PMBT particles. Thus, the crosslinking reaction was considered to be the driving force for the diffusion of the PBD-NH 2 into the PMBT particles.