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Polymer Synthesis & Manufacturing Systems Frank Crossman and Robert Milligan

Polymer Synthesis & Manufacturing Systems Frank Crossman and Robert Milligan. Overview

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Polymer Synthesis & Manufacturing Systems Frank Crossman and Robert Milligan

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  1. Polymer Synthesis & Manufacturing SystemsFrank Crossman and Robert Milligan Overview From our current knowledge of the chemical makeup of the Mars regolith and atmosphere, we develop a sequence of chemical processes that produce sufficient quantities of  chemical precursor and reagent stocks to (1) allow the synthesis of some important polymers for construction of a small permanent settlement in a two- Earth year time period and (2) provide the chemical industry infrastructure necessary to replicate that settlement in subsequent two-year cycles in arithmetic increments of settlers every two years.  F. Crossman and R. Milligan

  2. Scope • We describe the synthesis & manufacture of three polymers which represent three uses of structural polymers on Mars: • polyethylene for piping and a variety of general storage containers. A pellet extruder and die system will be used to produce piping and joints, blown bottles, and other structural shapes from extruded sheet and assembled by thermal welding. • polyester to provide a matrix for glass fiber reinforced composites used for habitat module construction. Glass reinforced polyester matrix composites will be used where structural strength is critical such as in the habitat pressure vessels. The cylindrical pressure vessel structures will be fabricated in a wet filament winding machine and the polyester matrix will be cross-link cured at room temperature. • epoxy for use as a structural adhesive for metal, glass, and composite joints. F. Crossman and R. Milligan

  3. Challenges in Polymer Manufacture on Mars … Imagine awaking in your bed one morning to discover that all man-made polymers in your daily life had disappeared. You have no sheets, no toothbrush, no computer, no microwave, no phone. You might have some cotton undergarments remaining… … Now imagine that you awakened in a world where oil is non-existent as well. Now you have no oil power, no gas heat, and no petroleum chemical stocks from which most chemicals and polymers are derived. … The challenge is to synthesize and manufacture polymers from scratch using available in-situ minerals and gases on Mars with chemical processing equipment that is sized to the Mars Homestead needs. F. Crossman and R. Milligan

  4. Sizing the Chemical Plant • Phase 2 Design studies have estimated the quantity materials needed to build a habitat sufficient to house 12 settlers. • 115 tonnes of fiber glass polyester composite, • 46 tonnes of polyethylene • 5 tonnes of epoxy adhesive • These materials are produced during a 400 day period at average daily production rates of • 70 kg/day - Unsaturated polyester resin and styrene for crosslinked polyester • 116 kg/day - Polyethylene • 12 kg/day - Epoxy • The size of the chemical reactor to produce 45 kg of unsaturated polyester resin (a viscous liquid) in a one batch a day process is • Volume = mass/density = 45/1.2 = 0.038 cubic meters or 9.4 gallons • Conclusion: The chemical plant needed to produce these quantities is more than laboratory scale but less than that of many pilot plants on Earth. Pdc Machines, Inc. F. Crossman and R. Milligan

  5. To Polymers working forward from known Mars resources • The known in-situ Mars resources that we start with are small in number and rely on the existence of a chemical processing capability already established on Mars to produce the bare necessities of life including methane for fuel and oxygen to breathe. • The 12 chemical building blocks are: • CO2 (carbon dioxide) and N2 (nitrogen) from the atmosphere of Mars • H2O (water), NaCl (salt), and hydrated CaSO4 (gypsum), silica, alumina, magnesia from the regolith of Mars • CO (carbon monoxide), CH4 (methane) from the making* of methane fuel • H2 (hydrogen) and O2 (oxygen) from the electrolysis* of water to obtain oxygen • * (see R. Zubrin, The Case for Mars, 1996) All the rest of the required chemicals and polymers are derived from this short list of pre-existing chemicals. F. Crossman and R. Milligan

  6. The end products Case 1: Polyethylene flake + remelted/formed = Polyethylene thermoplastic Case 2: Bisphenol A + Epichlorohydrin + Diamine accelerator = Crosslinked Epoxy Adhesive Case 3: Glass fiber + Unsaturated Polyester Resin + Styrene + Peroxide initiator = Glass Fiber Reinforced, Crosslinked Polyester Composite For this presentation we’ll detail the materials needed for the third case- glass fiber reinforced composites for pressure vessels. F. Crossman and R. Milligan

  7. Working backward from crosslinked polyester • Unsaturated Polyester Resin (1) whichis derived from • Maleic anhydride (2) whichis derived from • butane (3) (&O2 & VPO catalyst)whichis derived from • butene (4) (&H2 & Raney Ni catalyst) whichis derived from • methanol (5) (& Zeolite catalyst) whichis derived from • CO, H2, CO2 • and Ethylene glycol (6) is which derived from • oxirane (7) (& steam) is which derived from • ethylene (8) (& Ag and Al2O3 catalysts) whichis derived from • methanol • Styrene (9) whichis derived from • ethylbenzene (10) (& Fe catalyst) whichis derived from • benzene (11) (& Zeolite catalyst) whichis derived from • CO2, O2, H2, H2O • and ethylene (12) whichis derived from • methanol F. Crossman and R. Milligan

  8. Working backward to the basic 12 chemicals • And as the reaction initiator • Methyl ethyl ketone peroxide (13) whichis derived from • 2-butanone (14) whichis derived from • 2-butanol (15) whichis derived from • butene • and hydrogen peroxide(16) which is derived from • sulfuric acid (17) which is derived from • SO2 (18) (& O2, H2O & Vanadium dioxide catalyst) which is derived from • Gypsum thermal decomposition • and HCl (19) which is derived from • sulfuric acid • and NaCl . So…a total of 19 chemicals derived from the 12 basic chemicals have been identified for the production of crosslinked polyester on Mars. F. Crossman and R. Milligan

  9. Summary: all polymer precursor chemicals 8 inorganic chemicals • Proceeding in a similar fashion with the backward derivation of polyethylene and epoxy to the 12 basic chemicals, we discover that we need a total of • 8 inorganic chemicals produced on Mars • 30 organic polymer precursor chemicals produced on Mars • 15 recoverable catalysts imported initially from Earth in small quantity 30 Organic polymer precursor chemicals 15 Imported Catalysts F. Crossman and R. Milligan

  10. CH3COCH3 To 8. Cumene (2-Phenylpropane) Phenol 1-10 atm., O2 82 - 90oC, radical initiator 60-70oC [Cumene Hydro -peroxide CHP] H+,H20 Ca. 30% Vacuum distill unreacted cumene Weak caustic scrub to remove phenol, acids The analysis of each chemical reaction and the sequencing of these reactions has been carried to the level of detail shown on this slide and the next. F. Crossman and R. Milligan

  11. Ag CH2-CH2 O H2O HOCH2CH2OH 3a. 3b. ethylene glycol oxirane CH2=CH2 To ethylbenzene 4. ethene To polyethylene 1. To cumene 6. H2 MTO H2O2 HCl CO2 + CO CH3OH CH3CH=CH2 HOCH2CH=CH2 HOCH2CHOHCH2OH ClCH2CHOHCH2Cl 1. 2. 4a. 2-propenol 4b. HOAc 6. CaO propene methanol glycerol 4c. glycerol dichlorohydrin Cl2 Cl2, H2O CH2ClCH=CH2 CH2-CHCH2Cl O 5a. CaO 5b. 3-chloropropene As solvent for polyethylene 1. epichlorohydrin As co-reactant for LDPE O H2 O=C C=O CH3CH2CH2CH3 7/2O2, 400 - 480oC CH=CH CH3CH2CH=CH2 + CH3CH=CHCH3 7a. butane 0.3 - 0.4 Mpa maleic anhydride CH3CH2 CH3 H2SO4 H2O, H2S2O8 HOOCOOCOOH CH3 CH2CH3 Cu D CH3CH2CHOHCH3 CH3CH2COCH3 1 and 2-butenes 8c. 8a. 8b. MEKPO dimer 2-butanol 2-butanone, MEK CO CH3COOH 9. Acetic acid CO, O2 CH3OCOOCH3 CuCl, 130oC, 2000kPa Dimethyl Carbonate Aliphatic Organic Synthesis Sequence* * Patent Pending F. Crossman and R. Milligan

  12. Manufacturing the glass fiber Glass fiber is the least energy intensive fiber to produce on Mars. Three main types of fiber glass C glass (uncommon) used in corrosive environments. It is a soda-lime-borosilicate composition E glass used in printed circuit boards. Has the greatest number of components. S glass used in aerospace for its high strength and resistance to moisture. It has the highest strength and modulus of all these fibers and it is the simplest composition of only silica, alumina, and magnesia or simply magnesium aluminosilicate Since we want the strongest fiber, and it is the simplest composition using compounds that we know exist on Mars, we will make S glass fiber. F. Crossman and R. Milligan

  13. Homogenizing the glass composition • The first steps - • homogenizing the glass composition and • controlling the outflow temperature so that the viscosity of the drawn glass is constant F. Crossman and R. Milligan

  14. Drawing the glass fiber • Next steps: • Pulling fibers from the melt • drawing them down from 1 mm to 10.0E-6 m, a reduction ratio of 100 • Organosilane coatings are applied to protect the filament surfaces and also to promote better wetting and bonding between the glass filaments and the thermosetting resin during the filament winding process. • taking them up as a single strand on the forming winder or to fiber chopper F. Crossman and R. Milligan

  15. Manufacturing Methods for Composites • Using pressure and elevated temperature to aid infiltration of matrix around fibers • Autoclave Cure - Best properties, but requires massive pressure vessel/oven • VARTM (vacuum assisted resin transfer molding) - Uses woven dry fiber preforms and a massive weaving machine to create them. Best properties for very large structures (a/c wings) uses the pressure differential of 1 atm on Earth to pull the resin into a preform of fibers. But on Mars the ambient pressure differential will be ~1/2 bar or less. • Low pressure and low temperature cure processes include: • Filament winding • Open Mold processes • Sprayup • Hand layup We will use filament winding and sprayup F. Crossman and R. Milligan

  16. Filament winding the pressure vessel modules A Filament Winder is like a lathe with a long “cutting arm” that adds material (fiber and resin) instead of removing material The composites filament winding area may have to be ~30 m high to accommodate vertical winding of Homestead modules A large crane is required to support the mass and to maneuver it from vertical to horizontal F. Crossman and R. Milligan

  17. Sprayup Method for low pressure chambers This method of building up a 15% chopped fiber reinforced structure could have real value for the internal walls of low pressure underground chambers. It is a fast and non-labor intensive method of providing a seal. F. Crossman and R. Milligan

  18. Polyethylene Part Manufacture • Polyethylene can be synthesized in three steps: (1) methane to (2) ethylene to (3) polyethylene pellets or flake. • As a thermoplastic it can be remelted and re-extruded as sheet, piping, bottles. Extrusion machines and dies are complex and will need to be imported from Earth initially. • PE is limited to use at low temperatures due to creep/viscoelastic deformation. • It is chemically resistant to the point of being difficult to bond to other parts except by welding or by mechanical joining. Extrusion product lines are compact F. Crossman and R. Milligan

  19. Conclusions • We have analyzed the requirements to establish a chemical processingand polymer manufacturing plant on Mars capable of producing, over a period of 400 days, 166 tonnes of glass reinforced polyester composites for pressurized habitats, polyethylene piping and sheet, and a quantity of epoxy adhesive for general structural bonding use. • The route to polymer precursor formulation uses syntheses that do not rely on a petroleum precursor, the basis for much of today’s chemical industry. • Based on literature and patent searches, we have established the reaction sequence and conditions (temperature, pressure, catalyst, reactants, products) to produce the polymer end products. • In the process we have also established the production of a range of organic andinorganic chemicals and reagents that have other uses such as in the extraction and refining of metals and ceramics from the Mars regolith. The authors want to express their gratitude to Mark Homnick, Bruce MacKenzie, and Joseph Palaia the founders of the Mars Foundation, without whose support and encouragement this project would not have been undertaken. F. Crossman and R. Milligan

  20. KAAP Ammonia Process Methanol process HDPE and LLDPE ethylbenzene Styrene Gypsum to SO2 Benzene Next Step: Design the Chemical Plant • Plant design will use several batch reactors that operate in different T,P ranges • Most reactions occur at less than 550 deg C and 5 bar F. Crossman and R. Milligan

  21. The Next Step • The next step requires a chemical engineering plant design that is unique to Mars. • The reaction products must be stored and/or fed as reactants to the next reaction sequence. • Reaction chambers should be designed for production of several different chemical products that share similar reaction temperature and pressure conditions. • The reaction sequences must be prototyped to establish the reaction kinetics - optimum temperature & pressure conditions, catalyst type, and the yield of each reaction. While many individual chemical processes on Earth are licensable, they are designed for very large automated, continuous production in facilities that occupy hundred of acres. It is not evident that the Mars facility can take advantage of this prior art. • The Mars Homestead chemical processing plant will involve a total plant size that is on the order of a small pilot plant on Earth. • Like most pilot plants The Mars Homestead chemical processing plant will likely use batch rather than automated, continuous processing of chemicals, and this must be accomplished in a way that will not be human labor intensive. It will of necessity require robotic support and automated sensing and control equipment. • The Mars Foundation is soliciting the help of a Chemical Engineering group • at a university or research institute. F. Crossman and R. Milligan

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