Polymer chemists study large, complex molecules (polymers) that are built up from many smaller (sometimes repeating) units. They study how the smaller building blocks (monomers) combine, and create useful materials with specific characteristics by manipulating the molecular structure of the monomers/polymers used, the composition of the monomer/polymer combinations, and applying chemical and processing techniques that can, to a large extent, affect the properties of the final product. Polymer chemists are unique within the chemistry community because their understanding of the relationship between structure and property spans from the molecular scale to the macroscopic scale.
Polymer chemical professionals create, study, and manipulate the characteristics of polymers to create materials with specific chemical, biological, and physical properties. Polymers permeate every aspect of daily life, and it is difficult to imagine society without synthetic and natural polymers. Polymer products can be lightweight, hard, strong, and flexible, and may have special thermal, electrical, or optical characteristics. Because of their low cost, high specificity, and adaptability, polymers have a very wide range of applications.
They are used in the construction, furniture, electronics, communication, packaging, energy, health care, transportation, and sports & leisure industries, in everything from tractors to detergents to fabrics to aircraft. A polymer can be an end product in itself, or it can be an ingredient that changes the properties of another product.
The majority of polymer chemists work in industry, and focus on the end-use application of products, with an emphasis on applied research and preparation. Industrial polymer chemists need to adopt a business outlook and understand the commercial applications of the polymers they are developing and the needs of the market they are serving. They often find themselves working with the sales and marketing divisions of their companies to develop products that meet specific customer’s needs.
Most people employed in the polymer chemistry field have a college degree, with many possessing advanced degrees in chemistry, chemical engineering, biochemistry, or polymer (or macromolecular) science & engineering. About 22% of all polymer scientists have a bachelor’s degree, 14% a master’s degree, and 64% a PhD (ACS members, 2013 data). Employers recognize the importance of a solid education in the fundamentals of chemistry, as well as the value of the interdisciplinary degree available through programs in polymer science.
A polymer chemist’s work is interdisciplinary in nature, so polymer chemists must be able to communicate with professionals in a number of fields. Materials science and surface science are related fields, as is biochemistry (when studying biopolymers such as proteins, DNA, RNA or polysaccharides). While much research and product development in industry is product oriented, it requires scientists with a grasp of the foundations of chemistry, creativity, the ability to work together, and enjoy seeing the practical applications of their work.
According to Karl Haider, Research Fellow at Bayer MaterialScience LLC and 2014 Vice Chair of the ACS Division of Polymer Chemistry, Inc. “polymer chemistry and polymer science have evolved into disciplines in their own right, with undergraduate and advanced degree programs and curricula focused on the fundamentals of polymers. It is, however, a very interdisciplinary field, so education in the more traditional areas of physical, organic, inorganic, biological or analytical chemistry, as well as physics and engineering principles, will serve one well to meet the challenges being addressed in the field today.”
Although most polymer chemists work on applied research and development, there are opportunities for fundamental research (mainly in universities and federal laboratories) on the theory of polymers in solid and solution states, on the synthesis of new polymer structures, and on the mechanical, electronic, optical, biological, and other properties those new polymers will have. Fundamental polymer research is inherently interdisciplinary, spanning chemistry, physics, engineering, and even biological aspects. When theory predicts that a new polymer structure will have certain properties, synthetic chemists will devise ways to make the structure, and scientists can measure those properties.
Essentially all major areas of chemistry may employ polymer scientists and require an understanding of the fundamentals of macromolecules. Polymer chemistry is highly practical and used in many industries, including the following.
Adhesives are part of everyday life. They have evolved from the early, lower performance glues made from natural products to the versatile high performance adhesives used today. Adhesives are used to produce the multi-layer films used in food packaging to extend shelf life, and they are a critical component of the tamper-proof packages, which ensure the safety of over the counter medicines. Adhesives may need to be very flexible for use in label and tape applications, or to demonstrate high strength and long-term durability to bond the different metals and composites present in modern automobiles and aircraft. 3M, Bostik, DAP, Henkel, H.B. Fuller all work in this field, some globally and others regionally for more specialized applications.
Polymers are used in everything from seed coats to enhance germination to containers holding fresh produce in the grocery store; from mulch films to control weeds and conserve water to plastic pots in greenhouses. Sustainable agriculture has evolved to maximize land use and conserve natural resources and polymers, in the form of plastics, help this goal. However, the increased use of plastics designed for long term usage but used in short-term applications creates a disposal and environmental issue. Current research focuses on using natural polymers (i.e. carbohydrates such as starch and cellulose, plant proteins and oils) to create biodegradable plastics to replace petroleum-sourced plastics, as well as designing functional biopolymers that are sensitive to their environment and release agrochemicals on demand in a controlled fashion. Companies working in this area include Dow Agrosciences, DuPont, GE Polymers, Monsanto, NatureWorks LLC, SABIC.
The discovery of electrically conducting conjugated polymers in the late 1970s launched efforts to use polymers in electronic applications. The excellent light harvesting ability of conjugated polymers makes them ideal candidates for use in organic solar cells. The ability to solution process and roll-to-roll print conjugated polymers hold promise for lowering the manufacturing costs of solar cell technology. Research in this field largely focuses on the design, synthesis and processing of polymeric materials to improve device performances. There are many applications for conjugated polymers beyond solar cells, including light emitting diodes, field-effect transistors and sensors. Electrically conducting conjugated polymers have started to appear in commercial products, and with the promise of improved performance there are many opportunities for this emerging technology.
Biotechnology (“biotech” for short) is a field of applied biology that involves using living organisms and bioprocesses to create or modify products. The cultivation of plants has been viewed as the earliest example of biotechnology and the precursor to modern genetic engineering and cell and tissue culture technologies. Many biotechnology products are polymers, including proteins/enzymes, DNA, RNA, polysaccharides, and are used in in health care, crop production and other agriculture/environmental applications, and increasingly for the production of monomers or polymers. Enzymes for synthesis and biodegradation of materials are a growing area of research – using biopolymers to break down organic polymers (such as cellulose), to derive renewable basic chemicals or fuels. Companies that work in this area make seeds for crops that are resistant to certain diseases, seed coatings with specific properties, bio-based plastics, and plants that are drought resistant, and include Bayer, Cargill, Dow, DuPont, GenenTech, Metabolix, Monsanto, Myriant, and NatureWorks LLC.
The chemical industry is crucial to modern world economies, and works to convert raw materials such as oil, natural gas, air, water, metals, and minerals into more than 70,000 different products. These base products are then used to make consumer products, as well as in the manufacturing, service, construction, agriculture, and other industries. A majority of the chemical industry’s output worldwide is polymers and polymer-related, including elastomers (rubbers), fibers, plastics, adhesives, coatings, and more. Major industries served include rubber and plastic products, textiles, apparel, petroleum refining, pulp and paper, and primary metals. Examples of chemical companies involved in polymer chemistry include BASF, Bayer, Braskem, Celanese, Dow, DSM, DuPont, Eastman, Evonik, Huntsman, Mitsui Chemicals, SABIC, Shell Chemicals, and Wanhua Chemical.
Coatings are applied to the surface of many manufactured objects for decorative and /or functional purposes. Many coatings that we encounter daily in transportation products (cars, trains, planes, etc.), infrastructure (e.g. bridges, concrete), construction (paint for residential or commercial buildings), furniture, food packaging, or less frequently encountered but equally important, industrial machinery, pipes and tanks, and military vehicles, are based on organic polymer chemistry. In addition to aesthetics, coatings provide vital protection of the object from degradation by environmental factors, such as sunlight, moisture or oxygen. Steel bridges from the 1800s are still functional today largely because of the polymeric coatings that have protected them from corrosion. Some major companies involved in the polymeric coatings industry include AkzoNobel, BASF, Bayer MaterialScience LLC, Dow, DSM, DuPont, PPG Industries, 3M, and Sherwin Williams.
Modern medicine relies heavily on recent advances in polymer science. Medical applications of polymer chemistry span seemingly mundane materials such as latex gloves, bandages, and tubing, to applications as advanced as self-tying sutures, implantable medical devices, and artificial joints. Research in drug delivery is an excellent example of the impact polymer chemistry has had on the medical world: recent advancements allow for targeted delivery of therapeutics directly to tumor tissue using specially designed polymeric nanomaterials. Advancements in biodegradable polymers have created products for use in biomedical engineering applications as scaffolds that support tissue growth, then degrade slowly once implanted in the body.
Green polymer chemistry involves the development of green (environmentally-friendly) polymers, currently focused on more environmentally friendly packaging— incorporating biodegradable materials, edible food wrappings, bio-based/renewable monomers, and processes that minimize the amount of packaging material used. Additionally, efforts to develop polymers with lower environmental impact for more durable goods are on-going. Many suppliers conduct a complete life cycle analysis, that considers everything from starting materials through final disposal, including impact on the environment and health. Using starting materials, i.e., monomers, derived from bio-based, renewable resources, such as plants, or replicating polymers already present in nature is a successful strategy for many companies. For existing synthetic polymers, attempts are made to decrease the use of organic solvents and increase recycling and reuse. For example, for PET, ethylene glycol produced from natural feedstocks can be used. A leading commercially available “green” polymer is poly(lactic acid) or PLA. This thermoplastic can be used in packaging and many other applications. PLA can be composted at its end-of-life, or hydrolyzed to its starting monomers for reuse.
Polymers are ideally suited to applications in nanotechnology. The size of an individual polymer molecule can be on the nanometer size scale; by exploiting this feature polymers can be used as nano-sized building blocks to create devices with tiny features that are inaccessible by any other means. Recent breakthroughs in polymer chemistry permit the synthesis of new materials that can self-assemble into structures with nano-scale order in solution or in the bulk. These advanced materials have promising applications in the fields of nanomedicine, electronics, solar energy, and many more. Materials at the forefront of this field include carbon-based carbon fibers and carbon nanotubes that are used in electrical applications, as conductive adhesives, as high strength materials, as field emitters, in hydrogen and ion storage, as chemical and genetic probes, in solar cells, fibers, catalyst supports, superconductors, fibers and fabrics, energy storage, medical applications, films, nanomotors, elastomers, and many more places. Some major companies involved in nanotechnology include IBM, PPG Industries, and Solvay.
Polymeric materials are used throughout the entire oil and gas industry value chain, from upstream oil and gas production activities, to midstream, and finally downstream refinery production of fuels and specialty chemicals.They are often used in demanding conditions that include high temperatures, high pressures, and brine. Solid-state polymers include engineering materials such as plastics, fibers, and elastomers for use in oil well sites and off-shore platforms, with applications including construction of structures such as pipelines, proppants in hydraulic fracturing, and as coatings. Polymeric additives are used in upstream oil production applications as drilling fluids, well stimulants, corrosion inhibitors, scaling inhibitors, and viscosity modifiers. They are even used as components of cements used in protecting casings downhole.
In downstream operations, polymeric additives are used to improve performance features or overcome operational issues in the refinery, distribution systems and storage tanks, and in different fuel transport and combustion applications. Polymers may be used as stand-alone products to resolve specific issues at a refinery, may be combined with other products to create a multi-functional package for use in finished fuels or lubricants for the automotive industry, among other uses. Some specific examples of polymeric additives used in downstream applications include synthetic base stocks for lubricants, pipeline drag reducers, cold flow improvers, demulsifiers, deposit control additives, dispersants, friction modifiers, corrosion inhibitors, antifoamants, and viscosity improvers.
Rubbers are polymers that when stretched or deformed return to their original or near original shape, and are found in in tires, conveyor belts, hoses, toys, automobile parts, and thousands of other products. Rubber, often a mixture of polymers, has high resistance to heat, moisture, and other materials. Rubber can be found in nature in trees, shrubs, and other plants, and can be produced through chemical means (synthetic rubber). A third class called thermoplastic elastomers return to their original or near original shape when stretched or deformed, but melt when exposed to high temperatures and can be reprocessed. The majority of natural rubber is produced in Asia, but it can also be produced in India, Africa, Central and South America. It is sold as a commodity though traders. Synthetic rubber is produced by many companies around the world including Firestone, Goodyear, Lanxess, Michelin, Zeon and hundreds of others. Synthetic rubber is sold either directly from these companies or through distributers.
Polyester is the predominant class of synthetic fiber (72% of global synthetic fiber output), with the most common specific polymer being poly(ethylene terephthalate) (PET). This polymer is used in a wide range of textiles, with the largest application being in everyday clothing – often as a blend with cotton – and athletic apparel. It is also used in a range of nonwoven fabrics. The next most common class is polyamide, also known as nylon, and used in intimate apparel, workwear, industrial fabrics, outdoor apparel, and carpet. The two most important polyamides are polyamide-6,6 and polyamide-6, which are structurally similar and have similar properties. They differ in the monomers used and the polymerization procedure, which cause some tensile and thermal property differences. Spandex (elastane) is a polyurethane-urea thermoplastic elastomer which imparts elastic recovery when used as a minor component (1-25%) in fabrics with other “hard” fibers such as cotton, polyester, or polyamide. Synthetic fibers of polypropylene (polyolefin) are used in carpeting, nonwovens, and some athletic apparel (more commonly in Europe). Polymers are also used as coatings to impart specific properties to fabrics, including oil and stain resistant treatments (poly(perfluoroalkyl acrylates)), wrinkle-resistant treatments for cotton fabrics (glyoxal resins), and hydrophilic treatments which impart water absorbing properties – especially for polyester fabrics used in athletic apparel. Commercial producers of synthetic fibers include Hyosung, Indorama, Invista, Reliance Industries Limited, and UNIFI.