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Low surface energy polymers and surface-active block polymers

1987; Elsevier BV; Volume: 115; Issue: 2 Linguagem: Inglês

10.1016/0021-9797(87)90046-4

1095-7103

Morton H. Litt, B. R. Hsieh, Irvin M. Krieger, T.T Chen, Hua Lu,

Innovative Microfluidic and Catalytic Techniques Innovation

Block polymerization of different weight ratios of 2-(p-t-butylphenyl)-2-oxazoline (B) and 2-ethyl-2-oxazoline (E) with methyl p-nitrobenzenesulfonate as the initiator gave diblock co-oligomers with narrow molecular weight distributions in 100% yields. Co-oligomers with 40–50 wt% of B were excellent inverse emulsifiers for styrene/water (StW) polymerization: water-in-oil solid emulsions with internal phase ratios as high as 90% have been obtained using small amounts of the oligomers (⩾1 wt% of the total system). The total surface area of the water droplets is approximately proportional to the number of surfactant molecules, and thus the average pore diameter is proportional to the water volume divided by the surfactant concentration. For any given StW volume ratio, there is a maximum amount of emulsifier which can produce stable solid foams; higher amounts cause the emulsions to break.