Synthesis and Interface Activity of a Series of Carboxylic Quaternary Ammonium Surfactants in Hydraulic Fracturing

Table 5

Effects of NaCl concentrations on the foam abilities of different surfactants at room temperature.

NaCl concentration (mg·L^-1)	The initial foam volume (mL)				The half-life time (s)
	CTAAC	CTABU	CTAHE	CTACA	CTAAC	CTABU	CTAHE	CTACA
0	420	412	400	385	315	291	281	242
4000	428	425	416	391	325	295	288	249
8000	440	432	422	405	330	297	277	253
10000	405	392	372	360	280	267	245	209
40000	382	379	360	338	260	243	221	195
50000	355	350	332	285	245	299	205	179