Making plastics in Galileo's shadow.Making plastics in Galileo's shadow Soon after the Jupiter-bound Galileo probe left its berth on Atlantis on Oct. 18, the shuttle's Polymer Morphology experiment began collecting data that now amount to 15 stories worth of stacked typewritten type·write intr. & tr.v. type·wrote , type·writ·ten , type·writ·ing, type·writes To engage in writing or to write (matter) with a typewriter. pages. Scientists at 3M Co.'s Space Research and Applications Laboratory in St. Paul, Minn., aim to learn how weightlessness weightlessness, the absence of any observable effects of gravitation. This condition is experienced by an observer when he and his immediate surroundings are allowed to move freely in the local gravitational field. affects plastic materials. "We hope this experiment will teach us more about the physical properties, such as strength and elasticity, of polymers," notes chemicst and principal investigator Debra L. Wilfong. "Knowledge gained could be used to improve how we make tapes and adhesives on earth." The experiment is the company's fifth space project and the first under a 10-year research agreement with NASA NASA: see National Aeronautics and Space Administration. NASA in full National Aeronautics and Space Administration Independent U.S. . Since a polymer's physical properties depend on its underlying chemistry and how it is processed, the 3M researchers designed an experiment to eavesdrop eaves·drop intr.v. eaves·dropped, eaves·drop·ping, eaves·drops To listen secretly to the private conversation of others. on molecular changes occurring during the processing of polymers. Each of 17 sample cells held a disk-shaped film of either polyethlene, nylon-6, or a polymer blend. Each sample in turn was heated and allowed to cool while an infrared spectrometer took a snapshot of infrared emissions about every 3 seconds. Chemists use such data to infer the types of chemical bonds in samples. By examining the sequences of snapshots, the scientists hope to view a veritable motion picture of polymerization polymerization Any process in which monomers combine chemically to produce a polymer. The monomer molecules—which in the polymer usually number from at least 100 to many thousands—may or may not all be the same. and crystallization Crystallization The formation of a solid from a solution, melt, vapor, or a different solid phase. Crystallization from solution is an important industrial operation because of the large number of materials marketed as crystalline particles. processes in space. Earlier materials processing projects in space lacked consistent surveillance of real-time molecular changes. The scientists will now compare the space-processed plastics with lab samples processed in the normal gravity conditions of St. Paul. |
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