PARTICIPANTS
Chris Kingston (NRC Canada)
Richard Zepp (EPA)
Phil Sayre (EPA)
Wendel Wohlleben (BASF)
Yasir Sultan (Environment Canada)
Betsy Shelton (Applied Nanotech)
Douglas Hawkins (Dow)
Richard Fehir (EPA)
Justin Roberts (EPA)
Chris Roger (Arkema)
Anthony Andrady (NC State)
Eva Wong (EPA)
The following members participated in data collection and expert input, but did not participate in the voting process:
Darrell Boverhof (Dow)
Viktor Vejins (Nano-C)
Greg Fritz (EPA)
Mark Alberding (Lockheed Martin)
PROCESS DESCRIPTION
Beginning in January 2012, Task Group 2 (TG2) conducted a decision process to choose a set of polymers as the primary focus of the Materials white paper. TG2 is one of several multi-stakeholder expert groups under NanoRelease Consumer Products that aims to support the development of release measurement methods of MWCNTs in Polymer.
The initial intent of the decision process was to compile a list of 5-6 polymers that are most relevant for testing release measurement methods of MWCNTs in polymer systems.
First, the group created a detailed polymer database with information from academic citations and industry sources. The database included findings on general degradation of the polymer, commercial applications with/without MWCNTs or other CNTs, effects of UV exposure & temperature, mechanical stress, leaching, and available product details from companies.
The group drafted a specific set of polymer selection criteria in order to make the primary decision. The criteria were as follows (in no particular emphasis or order):
- Representation of a range of releases
- Brittle vs. soft, chemically resilient vs. chemically labile, environmentally stable (UV, moisture) vs. environmentally susceptible
- Likelihood of direct exposure to consumers and potential degree
- Commercial/industrial production volume
- Availability of data on the CNT/polymer system
- Likelihood of “modifications” to polymer during production or manufacture (coatings, additives, stabilizers, painting, etc.)
- Expert opinion
Each member listed their top five polymers based on the polymer selection criteria, the polymer database, relevant articles & reports, and their own expert knowledge. Members were asked to include rationale for each chosen polymer. Some members ranked their selections and others did not. In the evaluation of the selections, all selections were regarded equally and in no particular order.
A total of 12 experts participated the voting process, resulting in the tiered classifications shown below. Polymers considered in the database that received zero votes are not listed.
Tier 1 (7-11 votes each)
Epoxy
Polycarbonate (PC)
Polyurethane (PU)
Polyamide (PA)
Polyethylene (PE)
Tier 2 (5 votes each)
Polypropylene (PP)
Polyvinyl chloride (PVC)
Tier 3 (1 vote each)
cis-Polyisoprene (or other elastomer)
Polyether ether ketone (PEEK)
Polyethylene terephthalate (or other polyester)
Aluminum (or other metal)
Tire material (such as polyisoprene)
Listing of rationale [pdf]
The group is currently moving forward in compiling relevant information for the Tier 1 polymers. Information to be gathered includes: description of the polymer, use(s) when composited with MWCNTs, general potential for release of CNT and/or polymer degradation, MWCNT properties that may affect release, MWCNT-polymer interaction, CNT loading levels, use of stabilizers, production and end uses, and any other relevant life cycle information. TG2 is aware of the existence of polymer subtypes, and will attempt to address this issue in the white paper within time constraints.