Topic on User talk:Vis M

Regarding some of your last edits, I can't agree with the following ones:

1. : polymer is a mixture of macromolecules, P279 statement was correct (IUPAC Goldbook does not contradict it; especially as our 'mixture' is a subclass of 'chemical substance').
2. : this edit is not correct. 'plastic', 'polymer' and 'macromolecule' are terms that are often confused with each other. Polymer is a mixture of macromolecules, plastic is a material made of polymer.

@Wostr: Well, I disagree with #1. While your classification and terminology may be true in some fields, it does not hold true in more general cases.

A polymer need not be mixture of macromolecules. Crosslinked polymers are still polymers. Thermosetting polymers are also polymers. They are not a mixture (Q169336) as the chains are not physically combined together, but with chemical bonds. That's why I put the broader classification of chemical substance (Q79529)

Polymers are macromolecules, need not be a mixture. IUPAC's dedicated book for polymer terminology https://iupac.org/what-we-do/books/purplebook/ often treats both terms synonymously.

Also, both of my undegraduate and postgraduate degrees are in polymer technology and am currently teaching the same for polytechnic, so my edits were not out of some layman's confusion. Not using it as a leverage of any kind in Wikidata, but to remove any confusion here of my knowledge in subject.

Situations in which polymers = macromolecules (or in which a polymer is indeed a single macromolecule, a covalent network; the question remain here where is the boundary between a polymer and a polymer/plastic material) are IMO a small fraction of cases in WD.

As a side note of this discussion, we were always told that in English terms in polymer science are sometimes not used in its strict meaning, while in German and in Polish (my native language) we were told to strictly use terms like macromolecule, polymer, resin and plastic. Maybe it's also a bit caused by language differences: in Polish/German 'plastic' is a linguistic calque from English and is used only colloquially, terms like 'tworzywo sztuczne' i 'Kunststoff' are used here which means something like 'artificial material' or 'polymer material'.

My objections in this area mainly concern a few things:

1. in WD, these kinds of changes apply to the entire data model in a certain area. Changing 'mixture' to 'chemical substance' changes little in the WD model itself, but it makes us move away from other ontologies (such as ChEBI which defines 'polymer' as a 'mixture of macromolecules'). These differences must be justified in a certain way, because then the terms from both ontologies cannot be used interchangeably. Also, we can't have two different definitions described in one item, if there are some differences in the sources, a specific definition must be adopted in the WD ontology.
2. the field of polymer science in WD is neglected; starting from the simplest cases (like polietylen (Q143429)), we have only problems from the beginning, where several things are described in one item. It is not known whether item describes 'macromolecule', 'group of macromolecules', 'mixture of macromolecules' ('polymer') or 'plastic'. All four concepts are valid to be items in WD, but cannot be mixed in one item (just as we have different items for e.g. nikotyna (Q12144), rac-nikotyna (Q56697247), (−)-nikotyna (Q28086552) and (+)-nikotyna (Q27119762), for PE we should probably have at least two different items for 'mixture of macromolecules' and for a 'plastic').
3. recently, doing a lot of cleaning in terms of the chemical compounds themselves, I began to move polymers beyond the sphere of molecular entities and began to move them to mixtures (rodzaj polimeru (Q119896085) metaclass). This works for most of the most common cases, as can be seen from this discussion, it won't work for all.
4. Your knowledge can be invaluable in this case, because there are not many people willing to systematize certain areas in WD. However, for this, it would be necessary to write how data model for polymers should work, how to define and describe particular concepts etc.

Ok. But please note that the current subclass statement is true for thermoset, crosslinked polymer and vulcanized rubber. Best wishes.