Previously, my past few blog posts in this same category discussed some of the enviornmental and health hazard implications of some of our favorite modern materials, namely the issue of endocrine disruptors. Plastics are ubiquitous in modern mass production of electronics, so if you are building your own Raspberry Pi embedded electronics project, surely you want a nice plastic 3D-printed case, now don’t you? So, that’s where come back to the question of environmental and health hazardous materials full circle. Contemporary 3D printing for hobbyist projects is done generally at home with your own 3D printer that functions by means of melting plastic. Whenever you heat any material up, there is the potential for fumes to be emitted. Sometimes these are pleasant fumes like from a baking a delicious pie, other times they are noxious, headache-inducing fumes like from melting polycarbonate for 3D printing. And it is the second type that has been called into serious question. Are stinky chemicals bad for your health? Yes!
Sure, PLA 3D printing may still be a viable option for custom design, but maybe not so much for mass production. So, with all the potential for hazardous endocrine disruptors in mass produced materials, do you really need/want to use a similar material for your custom electronics project? As practical matter, I have found there to be very little technical justification for this. Paper mache can be just as strong and lightweight as plastic for the same thickness, which means its only disadvantage for hobby projects is lack of water resistance. Without needing to heat the material, you’ll get less stink when constructing it. Is this good enough for your project requirements? For me, given that many electronics are not rated waterproof, this is good enough for most of my projects.
Alas, if you think you can look to paper for a material less hazardous to the environment and your health, well maybe that is true. But, even in paper, due to the use of BPA in “printer ink, newspapers, and carbonless receipts,” you’ll find there are endocrine disruptors in recycled paper (i.e. the most desirable paper for you to use).
20190121/DuckDuckGo does pla plastic contain endocrine disruptors
20190121/https://www.motherearthnews.com/natural-health/dangerous-plastics-safe-plastics-zmaz09aszraw
Okay, so what if you grow your own paper? Can you rid yourself of the encodcrine disruptors that way? Not so fast. By this point in time, the phthalate endocrine disruptors have leached their way into many soils and groundwaters. Even if you grow your own trees to make your own paper, they might end up still containing phthalate endocrine disruptors, though maybe less than the quantity found in recycled paper.
Matter of fact, corn PLA plastic does not contain BPA. Also, according to this source, polyethyline (at least HDPE and LPDE) and polypropyline can be free of endocrine disruptors. (Namely, these materials almost never contain plasticizer additives. Whether they contain flame retardants that might be endocrine disruptors is unknown to me) Polycarbonate should be avoided. Also, do you smell the “new shower curtain stink” on some plastic? If so, that might be the phthalates you are smelling. Yep, that’s you inhaling the endocrine disruptors. It’s no surprise, then, that PLA, polyethyline, and polypropyline are some of the favorite materials to be used for 3D printing… alas, for 3D printing, other additives are used to make it more easily printable.
20190121/https://articles.mercola.com/sites/articles/archive/2011/06/24/europe-bans-penis-shrinking-chemical-america-does-not.aspx
So, about brominated flame retardants. What kinds of plastic contain them, and what kinds don’t? Now, there is a much longer and more interesting story behind this than yoi may realize. First of all, out of the many different kinds of brominated flame retardants, only some of them are toxic, such as the ones that are halogenated. Particularly, the halogenated ones are being phased out. The particular problem with halogenated flame retardants is that the small molecules can migrate out of the material, and that’s when it becomes toxic, in addition to reducing the fire retardant property remaining within the material. The modern material move is toward polymeric flame retardants. These chain-link bind with the plastic polymer very tightly, essentially fusing in to be an essential part of the plastic material at the time of manufacture, so they have much less prospensity to leak out of the material over time. Now, in the old days, we thought that brominated flame retardants were safe because they were fused into the plastic and couldn’t escape, but now we know better that they do in fact escape. That being said, suffice it to say that we do not fully understand the environmental impact of this new material, but with the best of our current knowledge, we believe it to be better than the previous options.
20190121/DuckDuckGo which plastics contain retardants
20190121/https://www.plasticstoday.com/materials/toxic-flame-retardants-are-still-being-used-plastics-even-though-there-are-alternatives/199932598957570
In this article I learned that PCBs were the precursor to PDBEs. First PCBs had to be phased out, PDBEs were rushed in without too much safety research, now PDBEs are being phased out too. Also, lower brominated PDBEs are more popular and more of a health concern than higher brominated PDBEs. The lower brominated PDBEs are known to bioaccumulate. Also, note that PDBEs can make toxic fumes when burning. So, for the sake of 3D printing at home, you want to avoid recycling any plastics that might contain flame retardants that could make noxious/toxic fumes.
20190121/http://nutritionwonderland.com/2009/09/plastic-troubles-brominated-flame-retardants-pbde/
Now, about the original question, well I guess I am content with the information I learned so far. Sure, I don’t know what kind of flame retardants a particular plastic may contain, but at least I know there are better optionws available. Okay… let’s keep searching.
20190121/DuckDuckGo what kind of retardant hdpe jug contain
The Wikipedia article contains no information about the flame retardants used in HDPE, but it does note that it is increasing in popularity and market share thanks to the concerns about PVC and BPA.
201900121/https://en.wikipedia.org/wiki/High-density_polyethylene
Let’s search more specifically.
20190121/DuckDuckGo polyethyline fire retardant
Ah, yes! Although this article doesn’t say much, some creative thinking around the material provided does enlighten. Reactive/incorporated flame retardants are added during the polymerization of the plastic and change the properties of the polymer; so, if you see the plastic recycling resin code on the container, you know it doesn’t use reactive/incorporated flame retardants. That leaves us with only the possibilities that it either is “added” to the material, that is mixing that does not alter the polymerization, or coated with the flame retardant. Adding is cheapest, so that’s your indicator as to the most likely method used for LDPE/HDPE food containers.
This also means right off the bat that we’re not going to be using a copolymerization flame retardant.
20190121/https://sciencing.com/how-12071421-make-polyethylene-fire-retardant.html
Now, speaking of all that discussion, now that makes me really wonder. For electronics cases, sure plain paper and cardboard are great materials to use, as I found cardboard being used in place of a circuit board in my 200 in 1 electronics kit. What makes paper fire resistant and smolder instead of burning is its tendency to absorb water vapor from the air. But, if you add glue that potentially makes the substance more flammable, that’s a no-go. Does adding Elmer’s glue to paper make it more flammable? It seems like it would… Elmer’s glue has a distinctive smell and it is made from petrochemical processes. I’d be surprised if a chemical like that didn’t have a flammability and didn’t use a flame retardant of some sort. Alas, Elmer’s glue is quite elusive to get information on due to its “proprietary” formulation. In their safety data sheet, they claim that Elmer’s School Glue is slightly flammable, but it doesn’t have a flash point, and many questions about hazards to human health or the environment either say “non hazardous” or “no data available” quite elusively. By the way, Elmer’s School Glue is not acid-free, so be forewarned if you are thinking of using it for archival grade constructions.
20190121/DuckDuckGo does elmer’s glue burn?
20190121/http://www.1st-class-software.com/qna/Would_burning_elmer_s_glue_toxic-qna77941.html
20190121/http://elmers.com/about/faqs
20190121/http://elmers.com/about/faqs/general
20190121/http://elmers.com/msds/category-search
20190121/http://www.elmersbrands.com/docs/default-source/sds’s-(safety-data-sheets)/se301.pdf?sfvrsn=2
Okay, enough of that, let’s try looking into ways to make your own vegetable oil. Surely you can create a less flammable glue that way. Well, maybe not. It appears that most vegetable oils need to be based off of starches or something with polymer chains that can break down and release energy in a fire. By far, the most popular recipe is wheatpaste. Second to that is one based off of corn starch.
20190121/DuckDuckGo how to make vegetable oil book binding glue
20190121/https://en.wikipedia.org/wiki/Wheatpaste
20190121/DuckDuckGo make glue from vegetables
20190121/https://www.ehow.com/how_12133280_make-vegetable-glue.html
20190121/https://sustainableecho.com/homemade-natural-glue/
20190121/https://www.wikihow.com/Make-Glue
Okay, so how is it done with Portland cement in concrete? We know that material is not flammable. Well, as it turns out, the exact chemical processes of Portland cement hardening are not well understood, but it is some kind of crystalizing that causes the adhesion, rather than polymer chains.
20190121/https://en.wikipedia.org/wiki/Portland_cement