I&EC REPORTS & COMMENTS Paper-like sheets from polyethylene Broader training programs for engineers begin N e w weather-resistant exterior finish saves repainting
IN SITU ENCAPSULATION WITH POLYETHYLENE Filter sheet and storage battery separators are already on the market: acoustical laminates, packaging materials, and speciality jilms and papers are on the way
T o find better battery separators, National Lead Co. sought to deposit a protective coating around cellulose fiber and came up with its Nalcon process which encapsulates fibers and particles in a sheath of high density polyethylene. The result is not only an improved battery separator but a variety of new materials with other potential uses as well. Most encapsulation techniques used in the past have been physical operations in which a coating was mechanically applied or a polymer was precipitated onto the substrate. T h e new process encapsulates materials by means of an in situ polymerization. Using ethylene gas, the polymer is formed directly on the surface of the material. Adherence
and wetting of the surface are said to be superior to results obtained when polymer is externally formed and physically deposited as in coating or dipping processes. I n the first step, cellulose fibers are dispersed in toluene and then pumped into one of two 5000-gallon reaction vessels. The polymerization zone is created by forming activated catalyst sites on the surface of the cellulose.. National Lead has not revealed the identity of the catalyst used, but it is probably a Ziegler type. Ethylene gas, introduced in the presence of the catalyst, condenses on the surface into long polymer chains which surround and gradually envelope the fiber, forming microscopically thin polymer shells around the cellulose skeletons. The polymer grows outwardly from the fiber surface so that a continuous sheath is formed with little penetration of the fiber itself. The amount of polymer and the thickness of the plastic sheath are controlled by the amount of ethylene
gas introduced. Thickness of the coating can be as low as 0.5 micron or as high as 60 microns. Molecular weight can also be controlled over an extensive range-from 50,000 to several million. Products containing from 5.0 to 90% polyethylene by weight have been produced. At the end of the reaction, water, air, or alcohol is added to deactivate the catalyst. The product is then filtered or centrifuged and either dried or slurried in water for paper sheet formation. Areas of Research. I n developing the Nalcon process, National Lead has concentrated work in three areas-encapsulating cellulose fiber, glass fiber, and carbon black. Encapsulated cellulose fibers can be formed into paper-like sheets on conventional paper-making equipment. The company’s new plant is completely integrated to produce the battery separators. Fram Corp. is using the Nalcon encapsulated material in an industrial filter cartridge. Possible applications include
PROPERTIES OF ENCAPSULATED FIBER CAN BE READILY CONTROLLED
Left,untreated cellulose fiber. Right, equal parts of cellulore fiber and polyethylene
Left, 72% jiber and 88% polyethylene. Right, hollow &aments formed by chemically extracting the cellulose core
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Sheet of encapsulated jiber zs permeable to water vapor but not to water. Vapor f r o m boiling container passes up through a sheet in the circular frame and condenses on the cooled vessel at the top. Then it drips down to the sheet and slides off into the lotLer beaker
molded objects, specialty plastic films and papers, mcmbrancs, insulation, acoustical and other construction boards, and food packaging materials. One phase of research led to sheets of a new type of porous plastic. By starting with sheets of Nalcon paper and extracting the cellulose core from each individual fiber with sulfuric acid, sheets made up entirely of a porous plastic material are produced. The sheet is made up of innumerable microscopic hollow plastic tubes matted together. Sheets of Nalcon encapsulated glass fibers have been made on an experimental basis. When layers of these are sandwiched between metal sheets or foil and pressed together, a high-strength waterproof laminate with low sound, heat, and electrical conductivities is formed. Laminates 14
with various metals have been formed successfully in complex dies. Xational Lead has also encapsulated minute particles of carbon black. Nalcon encapsulated carbon black can be processed by conventional plastic processing techniques. It is a clean handling, nonsludging product. Lt‘hen formed in calendered sheets it is strong, tough, flexible at low temperatures, and highly weather resistant. A variety of other materialsasbestos fiber, textiles, metal powders, pigments, and salts-can be encapsulated. Olefins other than ethylene can be used for the encapsulation process. The encapsulation process has been under development for five years, under the direction of Daniel F. Herman. Development work is continuing at National Lead’s research facility in Hightstown, N. J., to improve and broaden the applications of the process. Because properties can be readily varied and controlled, the company believes that Nalcon materials can be tailored to fit a multitude of needs. J . Ii. OLIN
ENGINEEl?ING EDUCAT10N Curricula must adapt to rapidly adcancing technology, and some important changes are in the making
Educators, practicing engineers, and engineering students have recognized the inadequacy of present methods of training engineers. Educators are striving to come up with the programs that will produce engineers who can meet the challenge. Societies and foundations are sponsoring surveys to determine future needs. New and different
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
programs are taking shape, and additional studies are delving into new concepts of engineering education to meet the needs of tomorrow. Are Four Years Enough? Carl E. Reistle, Jr., president of Humble Oil 6L Refining Co., expressed the views of many others in industrial and academic positions in a recent speech before the American Petroleum Institute’s refining division. Reistle says that it is not possible to turn out a qualified, broad-based engineer in the short space of four years. I t takes at least four years to give him the needed technical background. A fifth year of study, or maybe even more, should be added to give specialization and a chance to come to grips with the humanities-with history, language, political science, and economics. The Rensselaer Program. One answer to this problem may be the Rensselaer Program. Beginning in the fall of 1963, Rensselaer Polytechnic Institute w-ill revise its program of engineering education. R P I will no longer grant an engineering degree after four years of study. This major revision does not simply add another year to the requirement for a first degree, but it will establish a pre-engineering curriculum of three years which may be followed by a two-year professional curriculum leading to the degree of Master of Engineering, concentrating in a single area of engineering. At the end of the pre-engineering studies, those students who do not wish to enter the two-year professional course may elect a single year of additional work, with emphasis in a single curriculum, leading to a nonprofessional degree (Bachelor of Science). Students receiving the Master’s degree normally will also receive a Bachelor of Science after completion of four years of work. Also under study at R P I is a reorganization of the fields in which
I&EC R E P O R T S
the Master of Engineering will be offered. Curricula designated as materials, engineering management, transportation, information flow, systems design, structures design, energy sources and conversion, or terrestrial engineering may replace the traditional engineering fieldschemical, mechanical, civil, etc. Entering students will share essentially the same courses for the first three years, with emphasis on mathematics, basic science, engineering science, and humanities. The number of electives will increase as the student progresses. During the third year, students will decide whether to terminate their education with the nonprofessional B.S. degree after the fourth year or, if they are qualified, to continue for two years of specialized engineering study in the new professional school of engineering. Successful completion of three years of pre-engineering and two of graduate study will lead to the Master’s degree. Qualified students may continue their studies toward a Doctor of Engineering degree. Education After Graduation. Another major problem in today’s rapidly accelerating technology is the need for practicing engineers in industry and engineering professors to master the new sciences which have emerged since they completed their formal education. The success of a program inaugurated in 1938 by the Alfred P. Sloan Foundation for the advanced training of young business executives in the School of Industrial Management at Massachusetts Institute of Technology has led to a $ 5 million grant by the Sloan Foundation to M I T for the establishment of a Center for Advanced Engineering Study. The center will be a major addition to the M I T School of Engineering. It will serve the needs of three major managers, groups : engineering technical group leaders, and professors of engineering. (Continued on page 76)
TEMPERATURE CONTROL of CO, and other liquefiable gases now is handled on Hackney transports with greater simplicity. Our engineers have perfected a foamed-in-place technique for insulating with urethane-adding still another engineering “first” t o the many achieved during more than 61 years of manufacturing Hackney products. As a result, Hackney transports now offer efficient insulation for protection against erratic temperature changes; increased payload capacity; longer holding time without payload loss; increased structural strength; desirable low K factor. Effective, simplified temperature control for transports exemplifies the many advantages gained by users of all Hackney products-from pressure cylinders to shapes and shells and over-the-road transports. What type of transports interest you? Other Hackney products? Check this list, then write for further information: Transports for LP-gas .-.-., carbon dioxide -, anhydrous hydrogen chloride -, other liquefied gases -; Compressed Gas Cylinders -; Pressure Vessels -; Shapes and Shells for missiles -, or for industrial equipment -.
Pressed Steel Tank Company Export Division, 1445 S. 66th Sf., Milwaukee 14, Wisconsin, U.S.A. Cable Address: SEAMLESS, Milwaukee
Manufacturer of Hackney Products Since I902
CONTAINERS AND PRESSURE VESSELS FOR GASES, LIQUIDS AND SOLIDS Circle No. 510 on Readers‘ Service Card VOL. 5 5
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I&EC REPORTS
Study Continues. Even as changes are being made in engineering curricula, additional surveys are in progress to determine the direction that engineering education should take to meet the needs of the next 25 to 50 years. The American Society for Engineering Education just completed a two-year study of nuclear engineering education in which it concluded that workers in the nuclear field must receive an education which is not only technically competent, but which gives them a strong sense of responsibility. ASEE has just embarked on a three-year study, supported by a National Science Foundation grant of $300,000, which will make a national survey of engineering curricula and the entire range of engineers' responsibility in industry and government. Today's engineering teachers are training students whose active professional careers will extend into the next century, and ASEE hopes that by 1966 it will establish a frame of reference which those who design and operate engineering education programs can use to make proper decisions. Some of the questions up for investigation include the amount of scientific and nontechnical knowledge w-hich should be required for engineering degrees, and how to design a graduate program that will meet the practical needs of professional engineers returning from industry as well as the academic needs of resident graduate students whose emphasis is on research. ASEE conducted two previous studies of engineering education, one in 1929-34 and the second in 195255. Both produced important changes in engineering educational programs, and ASEE expects the new project to stimulate engineering deans and faculties to make changes which will enhance their programs and the talents of future engineers. J. H. OLIN Circle
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No. 512 on Readers' Service Card
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
POLYVINYL FLUORIDECORROSION-RESISTANT EXTERIOR FINISH Under normal weathering, estimated l;fe is 25 to 30 years A new film promises to be a long step forward in exterior finishes. Further, it should be particularly interesting to the chemical industry, both as a finish and as insulation jacketing where corrosive chemicals are handled. Introduced by Du Pont and called Tedlar, this polyvinyl fluoride film can be used to finish residential siding, architectural building panels, and industrial or commercial buildings. Because of its high elongation, it can be bonded to complicated relief designs. The film makes a breathing, fireresistant finish. It resists abrasion, but if nicks and scratches do occur, special touch-up liquids are available. And paints which adhere to the film surface have also been developed. Tough, pliable, and about as thick as the cellophane on a pack of cigarettes, Tedlar is made into rolls up to 6 feet wide and bonded to basic materials of construction such as wood, plywood, aluminum, or steel. Bonding with special adhesives is done at the factory by makers of construction materials, but when used as a roofing, the film can be applied in the field. The finish has a sheen resembling that of porcelain paint and is made either transparent or in a variety of shades. The current price of about $4.50 per pound gives an application cost approximately that of two coats of conventional paint. However, use cost is lower because the finish will probably last at least 25 years, much longer than the normal paint job. E. KELLER
