The membrane resistance per surface unit is determined as follows:
a) The sample is steeped 4 hours in a 1:1 mixture of 1.0 N NaCl and 1.0 N HCl and afterwards shaked for 24 hours in a 125 ml bottle containing 1.0 N NaCl.
b) Then the sample is exposed to a direct current for 8 minutes in a photoconductive cell containing 1.0 N NaCl. After the first 4 minutes polarity should be changed.
c) With the 3400 series the sample is heated in 0.1 N NaCl for 20 minutes at +100 °C, but with the 3100 series at +80-90 °C. Afterwards the surface resistance per unit is determined.
The membranes are supplied dry and should be stored at a dark place (max. +15 °C). Only for activation they have to be loaded in a 10 % salt solution at +55 °C for at least 3 hours
Good chemical stability in neutral solutions, in acid solutions (ph 0-7) and in alkaline solutions (ph 7-11)
Fair chemical stability in alkaline solutions (ph 11-14) an to mild oxidizing agents
Poor chemical stability to reducing agents
Electrical resistance: 15 Ohm/cm2 (0.1 N NaCI); 6 Ohm/cm2 (1.0 N NaCI)
Permeability: 96 % (0.5 N NaCI/1.0 N NaCI)
Water permeability: <3.2 ml/h/dm2 (at 0.35 kg/cm2)
Pressure resistance: min. 14 kg/cm2
Thickness: approx. 0.40 mm
Density: approx. 405 g/m3
Capacity: 1.22 meq/g
Max. temperature: +95 °C
Dimensional stability: wet: excellent; dry: good
Regulations: Approvals of the Food Additives Regulations; § 121.2593
||MC-3470||25 x 25||1||116.00|
||MC-3470||50 x 50||1||318.00|
||MC-3470||100 x 100||1||1,024.00|