I'm looking for any type of plastics data in the US. Is there a dataset around the waste or use of plastic materials?
Check www.quandl.com and search for "plastic united states" in the search bar at the top left corner. The results will show several free databases with plastics data from databases like the US Census Bureau which shows data on the imports or exports of plastic materials, or the United Nations Industrial Development Organization which shows data on employees and outputs in the plastics industry, or the US Energy Information Administration which shows manufacturing data for plastic products. Hope this helps in some way. [Disclosure: I work for Quandl]