NTR: "plastic film", "plastic foam"

[meichen-liu]

Dear editors,

As part of our work for UN environment on SDG 14 we would like to add the following terms:

Term: plastic film Definition: A piece of plastic which is flat and flexible is_a: piece of plastic

Definition Source: "Flat, flexible particle with smooth or angular edges"

Comment: The edge can be either smooth or angular | comment source

Notes: I chose to put the description of edge in the comment not in the definition because it is only mentioned in GESAMP report but not the other literature we read.

Term: plastic foam Definition: A piece of plastic which 1) has a near-spherical or granular shape and 2) is partially elastic that can deform readily under pressure is_a: piece of plastic

Definition Source: "Near-spherical or granular particle, which deforms readily under pressure and can be partly elastic, depending on weathering state"

Comment: They are usually white and/or opaque but can be any color. | comment source

I'll make a pull request regarding this issue.

Thank you!

[pbuttigieg]

Hi @meichen-liu thank you for your request:

plastic foam sounds more like a material than a piece of plastic. Nurdles, for example, can be made out of foam and have a specific shape.

I'd suggest adding plastic foam to the materials hierarchy (we'll need to handle "foam" as something with a quality of a foam (create in ENVO if not in PATO, post on PATO for them to create it and make an editor note on the ENVO class to obsolete and import the PATO class if they create it) and "piece of plastic foam" under "piece of plastic"

[meichen-liu]

I wasn’t aware of that, thank you for pointing that out @pbuttigieg !

When I looked it up, it seems like foamed plastic is more commonly used. So I will add foamed plastic and piece of plastic foam. Below are the definition I captured for them:

Term: foamed plastic Definition: A polymer which have a cellular structure that comprising a solid polymer matrix and voids containing air phase. is_a: polymer Exact synonym: plastic foam, cellular polymers, expanded polymers

Plastic foams, or cellular plastics, have a unique structure comprising a solid polymer matrix and voids containing air phase (Okoroafor & Frisch, 1995). Source

Foamed plastics are expanded materials with a cellular structure that have various identification names such as plastic foams, cellular foams, expandable foams, structural foams, blown foams, sponges, and microcellular foams. They may be flexible, semi-rigid, or rigid... Source

Term: piece of plastic foam Definition: A piece of plastic which 1) is partially elastic so that it can deform readily under pressure and 2) has a near-spherical or granular shape. is_a: piece of plastic Source

Also, for plastic film, @raissameyer and I looked into the GESAMP #99 report again (specifically Figure 9.4) and redefine its definition as following: Term: plastic film Definition: A piece of plastic which is 1) flexible, 2) have a flat surface area, and 3) are thin in its thickness. is_a: piece of plastic Source

Lastly, for foam as a quality, I am still thinking about how to define it. And as we already have foam as an environmental material in ENVO but without a definition, we may need to work on that as well. I will open another issue tracker to address them later.

[meichen-liu]

To better capture the meaning of piece of plastic foam while also have a corresponding term for foam in GESAMP, we will refine the definition of piece of plastic foam to:

A piece of plastic which has a matrix- or sponge-like structure with numerous, hollow internal spaces.

and add granule of plastic foam as a subclass, defined as:

A piece of plastic foam which has a near-spherical or granular shape.

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We also redefine foamed plastic as

A plastic which has a matrix- or sponge-like structure with numerous, hollow internal spaces.

Because the previous definition (a plastic which is structured as a matrix and contains gas in its internal spaces.) did not consider that an underwater foamed plastic is still a foamed plastic.