Plastics
Much of a typical commercial aircraft is made of lightweight plastic. Neutron studies are leading to safer, faster, more energy-efficient aircraft.
In the 1940s industrial chemists started synthesizing giant molecules called polymers to make strong, light materials called plastics. In the past 50 years, they have had a string of successes:
- Tougher, lighter materials used in cars and airplanes
- Bulletproof vests to protect police officers
- Synthetic threads for textiles
Any airline passenger who has struggled to open those little bags of peanuts knows how strong thin polymer films can be. The sometimes frustratingly durable packages are often blends of high- and low-density polymers. About 100 million tons of blended polymers are produced each year for consumer products such as sandwich bags and high-strength garbage bags.
Neutron scattering research could lead to plastics that are more flexible, durable, and recyclable.
Because of difficulties in commercializing new polymers, industry has turned increasingly to blending existing polymers to optimize the mixture's end-use properties (such as strength). Neutron scattering is the premier technique for studying such blends.
To develop these new blends for even higher-performance materials, a critical question is: Will the separate components of the polymer really blend to make a new material, or will they separate?
Neutron scattering is helping scientists determine the best polymer blends to make high-quality plastic products.
This question would likely be impossible to answer without neutron scattering. Neutrons have an excellent ability to penetrate materials without damaging them and allow researchers to determine whether a material is a true polymer blend or a segregated material.
Segregated material deteriorates over time, whereas true blends do not. Exxon, Phillips Petroleum, and Dow Chemical have used neutrons produced at HFIR to sort polymer blends from segregates. They can then determine how long the material will last and thus tailor the material for its intended application.
At SNS, such experiments can be performed in seconds, not minutes or hours. This allows researchers to quickly determine how well polymers will mix, how long they should be ground and compressed, at which temperature they should be melted together to get the best mixing, and which mixtures will form the best products.
For example, to help the recycling industry, SNS is helping scientists understand which polymers can be melted down and mixed to form useful polymer blends. Currently, less than 10% of polymers are recycled, so determining the degree of compatibility of different components can help in designing strategies for reprocessing and in evaluating the usefulness of the resulting material.
