The plastic that ends up in your house often is made with the help of manufacturing aids
developed and certified at NIST. |
Back yards of households with
kids often look like showrooms for the plastic industry. Massive pieces of colorful
polyethylene snap together into everything from picnic tables to indestructible playground
equipment. Kids or no, the polymer gala continues inside of the house: food packaging,
shampoo bottles, coffee-maker housings, plastic forks, video cassettes, shoes, toothbrush
handles, and hundreds of other items all have polymeric flesh to varying degrees. The National Institute of Standards and Technology has a hidden
hand in virtually all of these items. Almost all manufacturers of the polymer resins that
become the raw material for making specific products buy NIST's Standard Reference Materials
(SRMs). Many companies buy SRMs in which the distribution of molecular sizes, or molecular
weights, has been well characterized and certified. The distribution of molecular weights
is one of the most important properties that determines how a resin will behave during
processing. A resin with a huge range of molecular sizes does not melt, extrude, solidify
and otherwise behave like a resin consisting of same-size molecules. The availability of
such standards gives resin users laboratory benchmarks for comparing the molecular
personality of the resin they might have purchased from a manufacturer. And such tests
provide crucial data for managing factory processes and for maintaining consistent quality
in products. By the time any plastic ends up in your house, of course, those NIST data are
no longer discernible. |
