Film-Formation Property of Vinylidene Chloride-Methyl Methacrylate Copolymer Latex. Ii. Effect of Latex Storage Temperature

Abstract

Changes in the minimum film-formation temperature (MFFT) of 91:9 wt% vinylidene chloride (VDC)-methyl methacrylate (MMA) latex prepared by the seeded batch process during storage at 5, 20, and 40°C were investigated. MFFT of the latex rose the fastest at 20°C. Infrared absorption of fresh and stored latexes and wide-angle X-ray diffraction of powder polymers obtained by lyophilization of fresh and stored latexes indicated a much greater increase in polymer crystallinity during latex storage at 20°C than at 5 and 40°C. Observed increases in MFFT during latex storage correlated with increases in polymer crystallinity. Infrared absorption of polymer stored at 5-60°C in the dry state, such as lyophilized polymer and coating film, indicated that a polymer crystallinity increase was greater during storage at higher temperatures. These results showed that crystallization behavior of 91:9 wt% VDC-MMA copolymer latex differed from that of VDC-MMA copolymer in the dry state.