W. E. Mavcock and C. 8. Hoelzell
Fiber Industries, Inc. Charlotte, North Carolina 28201
I Improved Polymer Tubes
Although the use of polymer tubes described by Sorenson and Campbell2 permits the inexpensive, small-scale preparation of polyesters, the procedure presents two disadvantages: the tubes lack sidearms which must be attached by the user3; and isolac tion of the product requires the separation of polymer from small pieces of glass, an inconvenient and potentially hazardous procedure. The first disadvantage may be eliminated since tubes with side arms are available from at least one s u.~vlier.~ The second disadvantage may be eliminated by using polymer tubes (with side arms) modified by forming an approximately 2-cm long nipple on the bottom of the tube. Such tubes have mrn, been used for at least 15 8mn.i.d. years by I.C.I. Fibres of Great Britain. Our tubes I b m n ad. were obtained on svecial or11 lnm i d der from university Research Glassware, Carrboro, North Carolma, at a cost of $2.35 each. Although our use of these tubes has been Con,huction of Pyrex limited, they have given satpolymer tubes. ~ l isfactory l results. dimensions ore in cen~ h ,tubes are used in timeters unless othermuch the same way as unwirenoted;dimenrion. are not critical. modified tubes, following
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716 / Journal of Chemical Education
the procedure of Sorenson and Campbell. When polymerization is complete, the vacuum is released, the side arm closed with a clamp, and the tube removed from the bath (and wiped clean if necessary). The nipple is broken off and the polymer extruded into a pan of cold water by introducing slight nitrogen pressure via the capillary tube. The used polymer tube is di~carded.~ Polymer obtained by this modified procedure is free of glass, in a form more easily handled, and more amorphous than polymer obtained by the procedure of Sorenson and Campbell. A more amorphous state is desirable for melt-spinning or for studies involving d i e r ential thermal analysis (DTA) ; the amorphous-crystalline transition will not appear on a DTA thermogram if the polymer has been cooled slowly. 'Present address: Hdocsrbon Products Corporation, Hackensack, New Jersey 07601. l S o ~ ~ ~ W. s o R., ~ , AND CAMPBELL, T. W., "Preparative Methods of Polymer Chemistry," Interscience Publishers, Inc., (&divisionof John Wiley & Sons), New York, 1961, pp. 10-12. 8 These tubes may be obtained, in several sizes, from Lab Glass, Inc., Vieland, New Jersey, and NesterIFaust Manufacturing Corporation, Newark, Delaware. ' Nester/Faust Manufscturing Corporation, Newark, Delaware. Although the tubes may be salvaged by degrading the polymer remaining in the tube with hot ethylene glycol, cleaning with hat water or acetone, and redealing the broken tip, re-use of the tubes is discouraged for the following reesons: (1)the cost of a new tube probably is less than the cost of salvaging the old one; (2) use of hot glycol pre~entsa. safety hazard since the vapor can ignite; and (3) implosion hazards while under reduced pressure are inoreased if the redealed tube is not properly annealed.
