Polyethylene membrane properties

Several authors have discussed the ion exchange potentials and membrane properties of grafted cellulose [135,136]. Radiation grafting of anionic and cationic monomers to impart ion exchange properties to polymer films and other structures is rather promising. Thus, grafting of acrylamide and acrylic acid onto polyethylene, polyethylene/ethylene vinyl acetate copolymer as a blend [98], and waste rubber powder [137,138], allows... 

Islam MA, Dimov A, Malinova AL. Environment-sensitive properties of poly-methacrylic acid-grafted polyethylene membranes, J Membr Sci 1993 66 69-75. 

Greene, G., Radhakrishna, H. and Tannenbaum, R. 2005. Protein binding properties of surface-modified porous polyethylene membranes. Biomaterials 26 5972-5982. 

A polyethylene membrane containing silica filler has been developed as a cell separator for maintenance-free batteries. Characteristics of the polyethylene cell separator are shown in Table 7 and are compared with other materials used for the same purpose. The polyethylene cell separator is thinner than the other separators, so that the electrical resistance of the polyethylene separator is much lower than that of the other materials. In addition, the polyethylene separator with silica is readily wettable without any detergent, presumably because of the polarity of the silica filler. The polyethylene separator is heat sealable. This property greatly facilitates battery assembly. 

The sulfonation of polyethylene membranes was examined under various experimental conditions and the results showed that sulfonation greatly enhanced the water permeability of the resultant membranes. A lower concentration of chlorosulfonic acid at low temperature was preferable, so that only the surface and inner walls of the polymer were sulfonated and the mechanical properties of the membrane were not damaged. The electromicroscopy of polythene is facilitated by staining the polymer by immersing pieces of the polymer in chlorosulfonic acid at 60 °C for several hours. Chlorosulfonated polyethylene rubbers are useful for specific purposes, e.g. as ozone-resistant hoses. ... 

Choi SH, Park SY, Nho YC (2000) Electrochemical properties of polyethylene membrane modified with carboxylic acid group. Radiat Phys Chem 57 179-186... 

Surface fluorination changes the polymer surface drastically, the most commercially significant use of polymer surface direct fluorination is the creation of barriers against hydrocarbon permeation. The effectiveness of such barriers is enormous, with reductions in permeation rates of two orders of magnitude. Applications that exploit the enhanced barrier properties of surface-fluorinated polymers include (1) Polymer containers, e.g., gas tanks in cars and trucks, which are produced mostly from high-density polyethylene, where surface fluorination is used to decrease the permeation of fuel to the atmosphere and perfume bottles. (2) Polymeric membranes, to improve selectivity commercial production of surface-fluorinated membranes has already started.13... 

ENTER Membranes LLC has developed Teklon— a highly porous, ultrahigh molecular weight polyethylene separator for lithium-ion batteries. At the writing of this publication, the separator is available in small quantities. Pekala et al. characterized Celgard, Setela, and Teklon separators in terms of their physical, mechanical, and electrical properties. ... 

In lithium-based cells, the essential function of battery separator is to prevent electronic contact, while enabling ionic transport between the positive and negative electrodes. It should be usable on highspeed winding machines and possess good shutdown properties. The most commonly used separators for primary lithium batteries are microporous polypropylene membranes. Microporous polyethylene and laminates of polypropylene and polyethylene are widely used in lithium-ion batteries. These materials are chemically and electrochemically stable in secondary lithium batteries. 

In Table III the specific conductance and electro-osmotic coefficient (3) for the SPS membrane are shown together with the data for a conventional ion-exchange membrane, AMF C103 (16,17) (polyethylene-styrene graft copolymer containing sulphonic acid groups). It appears that there is a close similarity in properties of both membranes. ... 

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