At the 1939–40 New York World’s Fair, the world saw the first entirely synthetic fiber ??nylon, developed by DuPont in 1935. Made from common raw materials like coal, water, and air, it possessed steel-like strength. Today nylon remains ubiquitous in fabrics, home goods, sports equipment, musical instrument strings, and automotive parts. Here are five polymer categories shaping the future, two of which directly impact the packaging industry.
1. Bioplastics
Non-biodegradable plastics are a well-known source of environmental pollution. Even worse, their building blocks ??monomers ??come from non-renewable crude oil. Thanks to enzymes and catalysts used in production, this is beginning to change. Renewable energy sources like biogas can increasingly be converted into the building blocks for plastics and synthetic rubber. Preserving fossil resources makes these materials more sustainable, but unless they are also biodegradable, they remain an environmental concern. The packaging industry is a primary driver of bioplastic adoption.
2. Plastic Composites and Nanocomposites
Plastic composites embed fibers within polymers for greater strength or flexibility. Carbon fiber-reinforced plastics create lightweight materials for modern fuel-efficient vehicles. Fiber-reinforced plastics are growing rapidly ??the Boeing 787 and Airbus A350 are each 50% composites by weight. If not for cost, these materials would dominate all transportation.
Nanocomposites use nanoparticles including graphene to reinforce plastics, with potential applications from lightweight wind turbine sensors to higher-capacity batteries to bone-healing medical implants. Nature’s materials like wood exhibit astonishing structural complexity ??our current composites and nanomaterials are still relatively primitive by comparison.
3. Self-Healing Polymers
Regardless of how carefully we select materials for engineering applications, they inevitably fail under impact, fatigue, aging, and degradation ??sometimes catastrophically, as with the 2010 Deepwater Horizon disaster. Inspired by biological systems, scientists are developing self-healing materials capable of repairing damage once considered irreversible. Polymers excel at this capability, and multiple creative healing systems have been proposed since the discovery was first made at the turn of the century. Scaling these concepts to mass production remains challenging, but self-healing polymers represent the ultimate route to durable, fault-tolerant materials for coatings, electronics, and transport.
4. Plastic Electronics
Most polymers are insulators. The 2000 Nobel Prize recognized the discovery that doping polyacetylene with impurities could make it conductive. Since then, researchers have found that other polymers can not only conduct electricity but also function as light-emitting diodes ??enabling the prospect of flexible computer screens. While polymers face strong competition from silicon and OLED technologies, they offer advantages as inexpensive, solution-processable materials compatible with 3D printing. Conductive inks represent one promising application, though using polymers as the conductive component still requires extensive research.
5. Smart and Reactive Polymers
Gels and synthetic rubbers that change shape in response to external stimuli ??temperature, pH, light, ultrasound, or chemicals ??prove useful for smart sensors, drug delivery devices, and numerous other applications. Mechanophores, molecular units that change polymer properties under mechanical force, have broad industrial potential, especially when combined with self-healing technology. Other smart polymer applications include self-cleaning window coatings and medical sutures that dissolve as wounds heal.
References
- Wikipedia: Nylon: History and applications of the first synthetic polymer
- Wikipedia: Self-Healing Materials: Overview of self-repairing material technologies
- Wikipedia: Bioplastics: Biodegradable and bio-based plastic materials
- ISO 17088 ??Compostable Plastics: International standard for compostable plastic specifications
- ASTM D6400 ??Compostable Plastics: Standard specification for labeling of plastics designed for composting