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Changing lifestyles.

To pause and reflect on the impact of plastics on our lifestyles, to give the materials and the technology their due, can be a very positive experience.

Plastics have become so ubiquitous that they are almost unnoticed. They have become so reliable in the functions for which they are designed that their reliability is taken for granted. The effects of plastics' efficient production processes, of their performance capabilities, and of their potential for design diversity and cost reduction have diffused throughout our culture. However, the materials have become so interwoven into the fabric of our life experiences that, ironically, they have become underappreciated.

"From routine daily tasks to our most unusual needs, plastics have directly affected and improved our lifestyles in many ways," says Donald B. Shea, group vice president of the American Plastics Council, a joint initiative with The Society of the Plastics Industry, Inc. "Within a few short decades, consumers have come to consider the extraordinary properties of plastics as an expected part of everyday life. At home, during travel, in sports, in medicine, and in many other areas of our lives, plastics are now an important part of how we live."

"Plastics have 'freed up' people," comments Robert J. Cleereman, director, Materials Engineering Center, Dow Plastics. "Many products that used to be exotic now can be made more economically, and thus are more available. The design possibilities with these materials have stimulated our imaginations, so that we have many things today that probably would not otherwise exist."

Charles Haddad, manager, Advanced Engineering, Design Staff, Ford Motor Co., comments that "plastics are on the road to providing even greater opportunities to improve the quality of our lives; they are fast becoming the major material in our products. As these products are better understood, the consumer will see plastics as the luxury materials that they are."

Yet, Robert D. Albert, vice president, Automotive Materials Group, Dow Plastics, observes, "in spite of the broad and diverse impact of plastics on our daily lives, it is a paradox that the dependence we have developed on these materials is essentially invisible in the consciousness of the average citizen." Albert adds that it is "perhaps even an indication of the immaturity of the industry, when compared to alternative matured options."

One of the strong motivations of the American Plastics Council, in this context, is to close this apparent gap between the capabilities of the plastics industry, with its fundamental impact on our lifestyles, and the degree of public awareness of all that has been accomplished.


Around Thanksgiving time this year, Roger Young will cash in his chips and embark on the fulfillment of a long-held dream. He and his wife, Marilyn, will push off on a multiyear journey around the world on their sailboat, the Ballerina. And as they sail away from the dock, Young may well reflect, among other things, on the debt of gratitude he owes to, yes, plastics.

A plastics engineer, Young worked for eighteen years in applications development at Dow Plastics, followed by two years with his own Fort Lauderdale, Fla., consulting agency, Young Ideas, which focuses on innovative plastics applications, especially in the marine market. Young says that the radical change in lifestyle that will begin with this autumn's push-off, culminating ten years of planning and preparation--almost as long as he has been an SPE member--would have remained only a fantasy without the application of what he has learned as a plastics engineer. He is fulfilling a dream that not too long ago would have been a luxury only the very rich could have afforded. The Ballerina is a Lafitte 44 fiberglass/polyester boat, a single-masted cutter-rigged vessel displacing 28,000 lbs. It provides the strength, durability, weatherability, corrosion and rotting resistance, and low maintenance necessary for the extended voyage, with cost economy, compared to a boat fabricated of wood or metal. Built in Taiwan in 1983, the two-stateroom Ballerina has a weight-reducing cored fiberglass deck with a teak overlay; the hatches and portholes are all made of heavy-gage acrylic or polycarbonate sheet. For long-term wear, the seven different sails are mildew- and rot-resistant Dacron polyester.

Plastics were involved not only in the planning of most of the boat's functional requirements, but also in basic lifestyle decisions. From among a broad range of options, a dishwasher, and washing, sewing, and fax machines were given up, and other plastic-intensive products like a television set, VCR, refrigerator, microwave, and stereo system were kept. The power for these amenities will be provided by a variety of electrical generating systems, including a 165 amp alternator driven by the engine; a wind generator (which uses corrosion-resistant, glass-filled nylon, injection-molded blades); and a small, covered fluoropolymer solar panel.

Fresh water will be produced (at 3.6 gallons/hr) through reverse osmosis with polymeric semipermeable membranes; and a smaller hand-held unit will serve as an emergency kit. Most of the pumps have housings of glass-filled ABS or polypropylene. A 7 |ft.sup.3~ refrigerator and 5 |ft.sup.3~ freezer are insulated with a minimum of 4 inches of polyurethane foam.

The Ballerina's radar, electrical monitors, short- and long-range radios, and navigation instruments are all dependent on plastic housings (ABS, ASA, or polycarbonate), and laminated epoxy circuit boards minimize corrosion and facilitate the miniaturization that expands their functionality.

Scheduling the points on their route to try to dodge hurricanes and seasonal storms, the Youngs envision that their open-ended journey will take years. They plan to visit the Caribbean, South America, the Panama Canal, Hawaii, French Polynesia, the South Pacific, New Zealand, Australia, the Red Sea, the Suez Canal, the Mediterranean Sea, and northern Europe. The final portion of the trip will be from the Canary Islands to Barbados, where the Youngs will intersect their own path for the first time and thus complete a circumnavigation of the earth.

Plastics have been fundamental in the preparation for the long adventure, altering the Youngs' lifestyle while permitting them to keep numerous shoreside comforts.


Lighter weight, more efficient, and imaginative plastic products and equipment have been catalysts in drawing millions of people into more active lifestyles. "Access to plastics has stimulated new creative opportunities for the R&D divisions of sporting goods manufacturers," says Michael May, director of communications for the Sporting Goods Manufacturers Association (SGMA). "Plastics enable production of many sporting goods products that are stronger, lighter, more attractive, and that perform to a higher standard. Many never would have been invented if we did not have materials like plastics." Plastics have now become integral to practically all of the wide range of sports and recreational products with which people are expressing their more active lifestyles.

A recent SGMA study showed that sales of products in six athletic disciplines registered double-digit growth between 1989 and 1991: stair-climbing machines (240%), cross-country ski machines (127%), in-line skates (124%), beach volleyball equipment (112%), treadmills (55%), and basketball equipment (14%). According to the SGMA, manufacturers' total wholesale sales of sports-oriented products (including all materials)--equipment, apparel, and athletic footwear--is estimated at $32.6 billion in 1992, compared to $15.55 billion in 1982. A significant portion of the growth, May comments, can be attributed to the availability of plastics and the opportunities the materials have provided for design and production improvements.


Packaging, the plastics industry's largest market (14.6 billion lbs of resins sold in 1991), reacts to a myriad of elements affecting our lifestyles. Richard A.L. Eidman, marketing programs manager, and Thomas Hurford, marketing end-use sales and development manager, Du Pont Packaging, emphasize that it is the public's desires, as societal tastes and pressures change, that drive new packaging trends. They cite environmental concerns, issues of health and well-being, priorities for use of time, and the economical extension of the shelf life of food products as prime movers in the dynamics of packaging technology. The flexible polyolefin pouch, such as the Du Pont Canada Mini-Sip Pouch made of Sclairfilm polyolefin film, for example, reflects the pressures from a more environmentally conscious society for lighter-weight, less bulky packaging, and solid waste source reduction.

Polyolefin shrink film for tamper-evident packaging responds to the need to enhance our confidence in the security of many products. Barrier-type plastics packaging keeps pace with changing demographics as markets expand to include more complex ethnic meals requiring preservation of freshness and flavor, whether they are targeted for microwave or conventional ovens. Plastic-packaged foods with esoteric, gourmet spices and sauces, in combination with the microwave oven, can rescue a hungry, time-pressed individual from a Spartan peanut butter and jelly sandwich. Offering from 5 to 11 layers or more, depending on the specific product requirements, packaging technology has forever changed that person's lifestyle.


Plastics technology has made countless amenities available that previously were much less accessible to many segments of our society. Janet Bailey, an author in the area of food safety, says that "thanks to plastic packaging, we now can get foods from all over the world and can enjoy seasonal foods year-round. In the produce section of the neighborhood grocery store, potatoes from Idaho are likely to be next to blueberries from New Zealand."

One can have exotic fruits in winter; South African lobsters in Iowa; gourmet dinners in minutes. "Before the widespread use of modern plastic packaging," Bailey says, "we did not have these options. Modern refrigeration, transportation, and packaging have changed our lives dramatically. Today, plastic packaging can keep foods fresh even after they have traveled thousands of miles, been displayed in the supermarket for days, or lingered in the refrigerator for a week or more."

To ship and store fresh fruits and vegetables safely, different types of plastic film allow for their varied respiration rates. PET and HDPE films that drape over South African rock lobster leave little air space and prevent moisture loss, permitting it to be frozen and shipped anywhere in the world, and kept fresh and safe. A plastic film provides a necessary oxygen barrier for fish with high fat content, such as salmon, mackerel, bluefish, and tuna.

The impact on public health and lifestyles of the extension of food shelf life is probably greatly underappreciated. For example, apples used to be virtually the only fresh fruit available in winter and spring. Now a wide variety of fruits and other foods are available all year, allowing people to get needed nutrients easily and inexpensively.

Aseptic packaging--which includes paper, aluminum foil, and plastic--has proven invaluable in improving nutrition in developing countries where home refrigeration is uncommon. A container of milk need not be refrigerated and will not spoil for three to six months. The compact packaging expands pantry storage capacity and is compatible for children's lunch boxes or camping trips.

As Janet Bailey says, food manufacturers do not just sell food anymore--they sell lifestyle and convenience. "Over the past 50 years," she says, "the time people spend each day preparing food has dropped 80%. New families of plastic packages have been developed for compatibility with microwave technology. From plastic boil-in-bag pouches, to the prepackaged gourmet dinners in microwaveable plastic containers, plastics make it possible for us to lead busy lives and still eat well. Food packaging technology also allows for a wide variety of convenience foods. The largest poultry producer in the U.S. now offers more than 1000 different products.

"Although some people look back with nostalgia at the butcher shop of the 1940s," Bailey adds, "in those days refrigeration was the only way to extend shelf life. The development in the 1950s of coated cellophane to provide an oxygen barrier enabled producers to package meat in automated facilities and ship the product directly to the display case. Eliminating the store butcher from the distribution chain yielded major cost savings for consumers."

Because of modern packaging, the U.S. has the world's lowest food spoilage rate--less than 3%--and the world's least expensive food supply. As a result of the inadequate, or nonexistent, packaging in the former Soviet Union, food spoilage there can reach 50%. A recent study on how to eliminate Moscow's bread lines revealed that, contrary to popular belief, the problem is not a shortage of bread, but rather, getting the bread to the consumer before it gets stale. The study suggested that the biggest single change to ensure a reliable supply of fresh bread would be to put the loaves in plastic bags.

Plastics are also often the key to ensuring that other packaging materials--metals, glass, and paper--effectively perform their functions. In steel cans, internal plastic coatings prevent reactions between the food and the metal. Plastic coatings and laminates, in combination with aluminum foil, ensure excellent barrier properties. Plastic protects paper and paperboard products from moisture and permits their use in milk and fruit juice containers. As Janet Bailey says, "Without plastics, these and other essential packaging materials would be far less effective and, in some cases, not usable at all."


Plastics have transformed child safety. Author Vicki Lansky says that plastic products for children, "which are superior performers while generally quite affordable," have greatly reduced the number of accidents in the home. According to the National Safety Council, each month nearly 200 U.S. children, age four and younger, die in home accidents that can often be prevented by the use of inexpensive and easy-to-find plastic products.

Broken drinking glasses cause more than 100,000 injuries a year. In the kitchen, new varieties of shatterproof dishes and glasses allow parents to eliminate this threat to their children's safety. In 1989, there were more than 41,000 injuries related to cooking ranges and ovens. Plastic knob covers on stove and oven controls, and oven appliance locks, can prevent these injuries. Also, strong plastic drawer-latch locks prevent access to utensils and other sharp items.

In the bathroom, plastic child-resistant caps, and varied cabinet latches, play an important role in preventing accidental poisonings. Soft plastic bathtub spout covers protect children against bumps and bruises and prevent them from inadvertently turning on the hot water. Plastic safety guards over exposed outlets protect young children from electrical shock.

Years ago, Lansky says, parents knew only about accidents in the home that happened to friends and relatives. Now, government-compiled safety facts have focused on the known dangers. Plastic products are usually central to protecting children from many of the hazards in the home.

Daniel Della-Giustina, professor and chairman of the Department of Safety Studies, West Virginia University, says he is a safety expert, not "a plastics person," and has never thought much about the materials involved in safety. "But when you look at it in that sense, you see plastics everywhere," he continues. "The versatility and formability of plastics mean that a whole range of products can be made available to the consumer. Just look at smoke alarms. The body is all plastic, which helps make the unit inexpensive enough so that people can have one in each room or on each floor, of the house. Plastics technology is helping prevent accidents and save lives, and that's the bottom line."

Della-Giustina says medical researchers estimate that more than 350 accidental deaths can be prevented each year by use of hard plastic, cushioned bicycle safety helmets; baseball injuries in younger children can be prevented by a clear polycarbonate shield that attaches to the batting helmet and covers the lower part of the face; serious eye injuries can be avoided with plastic shatterproof lenses; and safety on staircases can be enhanced by simple plastic strips. The versatility of plastics in solving or alleviating countless safety problems appear appears limited only by creativity.


The broad-based impact of plastics technology on our lifestyles is nowhere more gratifying to see than in prosthetics. For example, the polymer technology of the last ten years enabled Joe Gaetani, a double-below-the-knee amputee, to set sprint records in the 1992 Paralympics in Barcelona, Spain. With Springlite Co.'s carbon fiber/epoxy lower limbs, he ran the 100-meter dash in 12.23 seconds and the 200-meter dash in 24.82 seconds.

The Northwestern University Prosthetic/Orthotic Center reports that each year since 1984, an average of 108,000 Americans have had lower limb amputations. Amputations resulting from accidents represent less than 15% of the total; the rest are due to illness, including cancer, vascular problems, and diabetes. About 75% of the total amputee population is age 50 or over. Typically, the lives of these people are markedly improved through the use of prosthetic devices.

Cindy J. Clinton, technical services manager for Model+Instrument Development (M+IND), says that throughout the world there are an estimated 4 million lower limb amputees, the vast majority of whom sustained their injuries in industrial activity, agricultural work, or war in developing countries. It should be noted, too, that prostheses for lower limb amputees represent only a portion of the prosthetic devices that people require today. "For amputees who want to, or must, increase their activity capabilities," says Clinton, "rising expectations have translated into heightened pressures to make prostheses even more efficient and affordable."

The development of plastic prostheses over the last decade is typified by M+IND's pioneering thermoplastic "Seattle Foot," Flex-Foot Inc.'s carbon fiber/epoxy design, and subsequent designs by Springlite and other companies using carbon/epoxy thermosetting or thermoplastics technology. While carbon-fiber-reinforced epoxy prostheses are noted for their superior strength-to-weight ratios and fatigue life, and facility of fiber orientation to meet individual requirements, an extra margin of resiliency, where it is

desirable under specific use conditions, and lower cost have been the principal drivers in the development of thermoplastic prostheses.

Building on the development of a spring-based thermoplastic foot by Ernest Burgess of the Seattle Prosthetic Research Study, M+IND commercialized its Seattle Foot in 1985, basing it on a monolithic hook-shaped leaf spring made of Du Pont's Delrin II acetal resin as its keel. The spring rate of the prosthesis is tailored to simulate the alternating compliance and resistance of a natural foot. A microcellular urethane foam cosmetic cover provides the lifelike appearance that is as much a revolution as the function of the spring.

One individual who has benefited from the Seattle Foot says that "I have so much confidence in the foot that I have applied for a job in the postal service, which will require me to be on my feet for extended periods."

Since the advent of the energy return/storage prostheses, many dynamic foot designs have entered the market, virtually all using a form of graphite/epoxy composite or thermoplastics, based on the leaf spring concept. The Seattle LightFoot, as one example, a later thermoplastic version introduced in 1991, is about 30% lighter and has a simplified, stronger Delrin II leaf spring design that accommodates individuals up to 300 lbs. Another thermoplastic design, the Seattle Ankle, which restores some lost ankle movements and reduces vibration, shock, and torque, utilizes a nylon 6/6 multiaxial ankle and shank. Use of CAD/CAM and automated thermoforming of polyethylene and polypropylene copolymer sockets has significantly increased fabrication efficiency and reduced material costs.

The earlier leaf spring devices were commonly designed with a fixed ankle connector or a secondary plate bolted to the shank, thus limiting the flexibility and performance of the system. Further advances in energy return devices were made possible by the use of carbon fiber/epoxy designs using an effectively solid configuration that eliminates the fixed ankle joint and allows natural torsional and bending flexibility without the interference of stiff joints. The simple, durable, and lightweight foot can be tailored to meet the needs of the individual amputee, whether geriatric patient or athlete.

"The geriatric patient may prefer a softer toe/heel stiffness and high degree of flexibility," says Eric Rubie, Springlite's project engineer, "to obtain a smoother rollover and a more efficient walking gait; selectively placing each ply of the unidirectional fiber material in the lay-up sequence provides a composite spring laminate of the desired stiffness. By contrast, an athletic patient may require a very high degree of dynamic response for a particular sport, such as running or sprinting. Basically, the achievable performance levels of the carbon fiber/epoxy prosthetic devices are dependent only on the amputee's lifestyle."


Plastics have also improved the lives of millions of people throughout the world in their use as durable, low-friction bearing materials with high fatigue life in artificial joint replacement. Richard R. Tarr, vice president, R&D, DePuy Inc., a leading supplier of orthopedic products, says that in the U.S. an average of 150,000 total hip replacement patients and 170,000 total knee patients per year enjoy pain-free, more active lifestyles as a result of modern plastics technology.

In 1987, the Du Pont Co. and DePuy formed a joint venture that has led to improvements in the plastic materials used for total joint replacement. Among the advances, ultra-high molecular weight polyethylene (UHMWPE), discovered earlier by Sir John Charnley of England to be the best available bearing material for artificial joint components, was enhanced for the prosthetic purposes, including improvements in mechanical properties and oxidation resistance. The material is known as Hylamer Orthopedic Bearing Polymer. Its properties are controlled by a Du Pont-developed proprietary thermodynamic process, which yields functionally specific versions for different joint replacements throughout the body. Tarr adds, for example, that the quality of the bearing material is "truly an improvement for the younger, more active patient requiring total joint replacement."

Ballerina is an appropriate name for a beautiful and graceful sailboat. A real ballerina, as well, owes something to plastics. Zina Bethune was able to return to dancing after a double hip replacement; UHMWPE was used as a porous coating material over a cobalt-chromium alloy. The coating eliminates the need for cement and encourages the body's tissues to grow into the implant, permanently fixing it to the bones and thus inhibiting loosening and failure.

Polymer Composites

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Title Annotation:includes related articles; effects of plastics
Author:Wigotsky, Victor
Publication:Plastics Engineering
Article Type:Cover Story
Date:May 1, 1993
Previous Article:SPE inducts officers for 1993-1994 at ANTEC '93 in New Orleans.
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