RtLi=>tz.ArXecause the surface of the plastic is mostly air, it is extrt^meh smooth to the touch. Plain polyethylene comes out with a soft-white color, instead of being clear, since light reflecting from the surface is diffused by the pores. • Not N e w . Actually, microporous plastics are not new. ESB developed the starch process about seven years ago. The only immediate object of t h e work was to make a better battery separator. Microporous PVC was just that, and has been used in ESB bat teries for several years. After setting u p the process on a commercial scale to make separators, the company h a d an idea that the product might i i a \ c other uses. But research continued at a slow pace until ESB became fully aware of the versatility of the product. Textiles seemed like a natural a p plication for microporous plastic b e cause the material both keeps out water and breathes. ESB made an agree ment with Reeves Bros., ;Λη old-lir^ ;. xtile firm which had the needed experi ence in production and marketing. Re sult: ESB-Reeves Corp., formed in mid-May of this year. It is licensed by ESB to use the porous plastic proc ess. T h e protective clothing market will be tapped first, in everything from raincoats to baby pants to exposure suits for the military. The plastic is also an excellent thermal insulator and may be used in garments for this pur pose. O n c e textile outlets are estab lished, ESB-Reeves will push other uses. Among the possibilities: Filtration. Microporous plastic proc essed with cornstarch makes an abso lute filter for material 4 microns a n d over. Even smaller particles can be filtered if a finer starch is used. W i t h organic solutions that wet plastic, the material can be used as is. Water solu tions can b e handled by simply treat ing the plastic with a wetting agent. It's even possible to separate t w o liquids by filtration if they differ in surface tension. For example, micro porous plastics might be used to filter traces of water from jet fuel. Medical. A microporous plastic bandage on small cuts allows the wound to heal in one third the time needed with a conventional plastic covering, ESB-Reeves finds. On burns or other wounds where irritation is a problem, the plastic gives a silk-smooth surface. The University of Pennsyl vania is testing a blood oxygenator based on the plastic. Current devices I that d e p e n d on direct contact between ι
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intensities are closer to realization than continuous beams of the same order of magnitudes.
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