(DE3781081-G)      A process for making a composite polymer membrane comprises irradiating a membrane that comprises a first material (I) which defines a porous matrix and a second material (II), blocking the pores of the matrix, which contains a crosslinking agent (III) and a photoinitiator and is crosslinked under UV radiation.    A porous matrix of (I) is formed by removal, esp. liq. extn., of a pore forming material, esp. polyethylene oxide, dispersed in (I). (II) is impregnated in the resulting poers and is polymerised in situ by irradiation.    Claimed use of (I) as polyethylene contg. polyethylene oxide (II) as an ethylenically unsatd. acid or ester; and (III) which forms a sec. radical or tert. non-conjugated radical when irradiated and is used in an amt. of at least 0.1 wt.%.    USE/ADVANTAGE -   The membrane is useful as an ion exchange membrane having an ion exchange capacity of more than 1 milliequiv./g and is esp. useful as an electrode separator in an electrochemical device contg. an anode, a cathode and an electrolyte. Other uses include biological application such as dialysis.    (US5256503-A)      Mfr. of polymer membrane comprises exposing surface of a membrane to UV radiation. The membrane comprises a 1st polymeric material defining a microporous matrix and a 2nd material including photoinitiator which at least partially fills or blocks the matrix pores, the membrane having thickness of not than 250 microns. During UV irradiation, the 2nd material is polymerised and crosslinked. The pref. 2nd material is ethylenically unsatd. acid or its ester pref. mixed with crosslinking agent chosen from crosslinking agent forming a sec. radical or tert. non-conjugated radical on irradiation.    Pref. the 1st material is polyethylene with the porous matrix being formed by liq. extn. of polyethylene oxide dipsersed in it.    USE -   Useful as ion-exchange membrane for e.g. electrode separator in certain electrochemical devices.    (JP2520928-B2)      A process for making a composite polymer membrane comprises irradiating a membrane that comprises a first material (I) which defines a porous matrix and a second material (II), blocking the pores of the matrix, which contains a crosslinking agent (III) and a photoinitiator and is crosslinked under UV radiation.    A porous matrix of (I) is formed by removal, esp. liq. extn., of a pore forming material, esp. polyethylene oxide, dispersed in (I). (II) is impregnated in the resulting poers and is polymerised in situ by irradiation.    Claimed use of (I) as polyethylene contg. polyethylene oxide (II) as an ethylenically unsatd. acid or ester; and (III) which forms a sec. radical or tert. non-conjugated radical when irradiated and is used in an amt. of at least 0.1 wt.%.    USE/ADVANTAGE -   The membrane is useful as an ion exchange membrane having an ion exchange capacity of more than 1 milliequiv./g and is esp. useful as an electrode separator in an electrochemical device contg. an anode, a cathode and an electrolyte. Other uses include biological application such as dialysis.