|
You can make every plastic available on Earth from resources on Mars. Most plastics are hydrocarbon polymers, made from water and air using electricity. Other plastics require chlorine from salt, or nitrogen from air. Fluoropolymers are extremely strong, durable, endure temperatures much colder than the coldest day at the south pole of Mars in winter, immune to any form of acid or alkali you'll find in the soil, highly resistant to strong UV, and light. Common fluoropolymers are Teflon and Goretex, but they all require fluorine. Unfortunately we haven't found fluorine on Mars yet. We can look at other plastics until we find it.
The first step is to make hydrogen and carbon monoxide gas.
Hydrogen
Hydrogen is the most fundamental part of materials production. Almost all chemical reactions to produce polymers produce heat. Steel refining requires hydrogen and carbon monoxide; as shown below CO requires hydrogen. The majority of energy consumed for materials production will be hydrogen production. The process is electrolysis of water across a proton transport membrane:
H2O → 2 H2 + O2
Carbon Monoxide
Carbon Monoxide is produced by the process is called Reverse Water Gas Shift (RWGS):
CO2 + H2 → CO + H2O
This reaction is mildly endothermic, occurring rapidly with an iron-chrome catalyst @ +400°C or greater.
Energy consumed: 9 kcal/mol
This reaction is driven directly by heat. Energy per kg of CO: 691.3 kcal
Methane
Methane is the smallest hydrocarbon, consisting of a single carbon atom with 4 hydrogen atoms. The majority of this gas will be used for fuel: rocket fuel, rover, or back-up generator. The process is a Sabatier reactor:
CO2 + H2 → CH4 + 2 H2O
An alternate method uses RWGS with electrolysis:
3 CO2 + 6 H2 → CH4 + 4 H2O + 2 CO
Ethylene
Ethylene is not a plastic, but it is the starting point to manufacture almost all other plastics.
Ethylene is sometimes called Ethene, but don't confuse it with Ethane (spelled with an "a").
Ethylene is two carbon atoms double bonded to each other, and each of the extra bonds of the carbon atoms has a hydrogen atom stuck to it.
The formula is C2H4 but to demonstrate the structure it is often written as H2C=CH2.
This description for making it is taken from the book "The Case For Mars" page 182.
Hydrogen and carbon monoxide can be reacted in the presence of an iron catalyst to form Ethylene:
2 CO + 4 H2 → C2H4 + 2 H2O
Heat producted: 49.4 kcal/mol
Heat per kg of ethylene: 1761 kcal
References are RWGS by Tom Meyer of UC Boulder,
MAHOSS by Pioneer Astronautics,
Process For Producing Ethylene And Propylene by Zelinskii Institute of Organic Chemistry, and
Estimation Of Surface Site Density On Iron Fischer-Tropsch Catalysts By Means Of A Test Reaction.
Benzene
6 CH4 → 9 H2 + C6H6
Reference, a device to make it: MetaMars
Toluene
7 CH4 → 10 H2 + C7H8
also produced by MetaMars
Naphthalene also known as phthalic acid
10 CH4 → 16 H2 + C10H8
also produced by MetaMars
Phenol
benzene (C6H6) + hydrogen peroxide (H2O2) → phenol (C6H5OH) + H2O
Reference here
or
toluene (C7H8) + permanganate (HMnO4) → phenol (C6H5OH) + something (possibly CO2 + H2O + Mn)
Reference Manganese Chemistry
Ethylene glycol also known as glycol
ethylene (C2H4) + ½ O2 → ethylene oxide (C2H4O)
ethylene oxide + H2O → ethylene glycol (CH2OH)2 over a silver catalyst @ 250°C
A direct use for glycol is anti-freeze, used commonly for windshield washer fluid.
Acetone
made with the Hock process.
Cumene, also known as iso propyl benzene or i-propyl benzene, is oxidized to form cumene hydroperoxide. This step is mildly exothermic, 28kcal/mol. Cumene hydroperoxide is hydrogenated (with a positive hydrogen ion) to form phenol and acetone. It produces 60 kcal/mol.
An alternate process to make phenol converts toluene plus oxygen to benzoic acid plus water, then benzoic acid with oxygen to phenol and CO2. However, although this is easier because it starts with toluene instead of cumene, it doesn't produce acetone. Polycarbonate requires both phenol and acetone.
Reference: CHEM 462
Cumene
made from benzene and propylene.
Reference: Wikipedia
Terebinth also known as oil of turpentine or spirits of turpentine
Terebinth is refined from oil of trees, such as the turpentine or pine trees.
Synthetic turpentine is known as mineral spirits or petroleum spirits, but is a group of chemicals with various chemical formulae.
Terebinth has the formula C10H16. MAHOSS described above can make olefins, such as C10H20.
I think dehydrogenation can make terebinth from an olefin.
Used to make PET and Mylar.
Thermoplastic vs Thermosetting
What we call plastic is technically called polymer. There are two groups of polymers: thermoplastic and thermosetting.
Thermoplastics soften and melt when heated, so they can be molded and reused almost indefinately.
Thermosetting polymers harden permanently after being heated once. Heating them again will only cause them to harden further, or burn.
Common thermoplastics are listed here.
Polyethylene (PE, LDPE, HDPE)
Polyethylene (PE) resin is a simple plastic. It is formed by polymerizing ethylene.
The chemical formula is [–CH2–CH2–]n where n is the number of units.
Polyethylene has two variations: Low Density Polyethylene (LDPE) has 4 to 6 carbon atoms attached randomly along the backbone.
High Density Polyethylene (HDPE) is a long polyethylene molecule without any side groups.
This permits the molecules to pack more tightly, resulting in slightly higher density.
One reference for making polyethylene is the Aus-e-tute.
Polypropylene (PP)
Polypropylene is polymerized propylene (CH3–CH=CH2) and has a methyl group (–CH3) branching off every other carbon on the backbone.
The difference between propylene and ethylene is replacing one hydrogen atom with a methyl group.
ethylene → propylene (CH3CH:CH2)
Polymerization of propylene
Acrylic
The technical name for acrylic is Polymethyl Methacrylate (PMMA).
Acrylic resin is a polymer of either acrylic acid (H2C:CHCOOH) or methacrylic acid (CH2:C(CH3)COOH).
Acrylic acid is usually formed by oxidation of acrolein (CH2CHCHO). Acrolein is formed by decomposition
of glycerol (CH2OHCHOHCH2OH) at 290°C. Glycerol is a trihydric alcohol that can
be formed during the fermentation of sugars if sodium bisulfite is added with the yeast, or it can be
made from propylene (CH3CH:CH2). Acrolein can also be formed by oxidising allyl
alcohol (C3H6O). Propylene is made from ethylene (H2C=CH2).
ethylene → propylene (CH3CH:CH2)
propylene → glycerol (CH2OHCHOHCH2OH)
glycerol → acrolein (CH2CHCHO) @ 290°C
acrolein + O2 → acrylic acid (H2C:CHCOOH)
Polymerization of acrylic acid
Lexan technically known as Polycarbonate (PC)
acetone (C3H6O) + phenol + HCl → bisphenol-A
bisphenol-A + NaOH → sodium salt of bisphenol-A
CO + Cl → phosgene (COCl2)
sodium salt of bisphenol-A + phosgene → polycarbonate
Polyvinyl Chloride (PVC)
Polyvinyl Chloride is prepared from vinyl chloride (CH2=CHCl). PVC includes chlorine, which can be harvested from Martian regolith.
Sojourner analyzed Martian soid with its Alpha-Proton-Xray Spectrometer (APXS) and found 0.7% to 1.2% chlorine; the average was 0.85%.
Notice the only difference between vinyl chloride and ethylene is replacing one hydrogen atom with chlorine.
The normal process is to add salt (sodium chloride) to water and use electrolysis (run electricity through it) to release chlorine gas.
Ethylene and chlorine gas combine to form ethylene dichloride. That is exposed to heat to convert it to vinyl chloride, also known as vinyl chloride monomer (VCM).
That is polymerized to form PVC, also known simply as vinyl.
Polystyrene (PS)
Polystyrene, produced from styrene (C6H5CH=CH2), has phenyl groups (six-member carbon ring) branching off every other carbon on the backbone.
The difference between styrene and ethylene is replacing one hydrogen atom with a phenyl group.
Polystyrene foam is used for egg cartons and as styrofoam insulation.
benzene (C6H6) → phenyl (C6H5) + H2
ethylene + phenyl → styrene (C6H5CH=CH2)
Polymerization of styrene
Mylar (PET)
The technical name is Polyethylene Terephthalate (PET). It is best known as plastic pop bottles, although mylar is also coated with iron oxide to produce audio and video tape.
It is formed by the reaction of terephthalic acid (HOOC–C6H4–COOH) and ethylene glycol (HOCH2–CH2OH), which produces PET [–OOC–C6H4–COO–CH2CH2–]n.
Polybutadiene rubber (BR)
butene is an olefin, it can be produced by MAHOSS by a Fischer-Tropsch synthesis reaction: 4 H2 + 8 CO → C4H8 + 4 CO2
Dehydrogenation: butene → butadiene (CH2=CHCH=CH2) + H2
Ziegler-Natta polymerization: butadiene → polybutadiene rubber [–CH=CH–CH=CH–]n
Acrylonitrile Butadiene Styrene (ABS)
ABS is formed by combining acrylonitrile (CH2CHCN) and styrene (C6H5CH=CH2).
Acrylonitrile and styrene are dissolved in polybutadiene rubber [–CH=CH–CH=CH–]n, which allows these monomers to form chains by attaching to the rubber molecules.
Phenolformaldehyde also known as phenolic (adhesive for pink fiberglass batt insulation)
phenol + formaldehyde → phenolformaldehyde
Nylon
The technical name for nylon is Polyamide (PA).
There are two basic ways to produce nylon, resulting a few variations.
One way is to react dicarboxylic acid (an acid containing two carboxyl –COOH groups) with diamines (carbon molecules with the ion –NH2 on each end).
Examples of nylon produced this way are nylon-6,6 and nylon-6,10. The numbers represent the number of carbon atoms in the diamine and dicarboxylic acid, respectively.
The other way is by condensing amino acids. An example of this is nylon-6. The steps to make nylon-6,6 are:
NH3 (ammonia) + CO (carbon monoxide) → HCN (hydrogen cyanide) + H2O
butadiene + 2 HCN → adiponitrile
adiponitrile + 4 H2 → hexamethylene diamine
N2 + O2 → 2 NO2 (nitrogen dioxide)
NO2 + H2O → HNO3 (nitric acid)
benzene + 3 H2 → cyclohexane (using rhodium on carbon catalyst)
cyclohexane + O2 → cyclohexanol and cyclohexanone
cyclohexanol/cyclohexanone + nitric acid + air → adipic acid
hexamethylene diamine + adipic acid → nylon
Melamine resin
NH3 (ammonia) + CO2 (carbon dioxide) → (NH2)2CO (urea) + H2O
3 urea → C3H6N6 (melamine) + 3 H2O
melamine + formaldehyde → melamine resin
Uses: Malmac kitchen utensils or plates, and the main constituent in high pressure laminates such as Formica, Arborite, laminate flooring, and whiteboards.
Note: Melamine resin is a thermosetting polymer; it gets hard with heat, it doesn't melt.
| 
