Aug-6-05F. Crossman and R. Milligan1 Polymer Synthesis & Manufacturing Systems Frank Crossman and...

Aug-6-05 F. Crossman and R. Milligan 1

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are needed to see this picture. 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.



are needed to see this picture. 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.



are needed to see this picture. 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.



are needed to see this picture. 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.


are needed to see this picture.



Pdc Machines, Inc.



are needed to see this picture.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.



are needed to see this picture. The end products

Case 3: Glass fiber + Unsaturated Polyester Resin + Styrene + Peroxide initiator= Glass Fiber Reinforced, Crosslinked Polyester Composite

Case 2: Bisphenol A + Epichlorohydrin + Diamine accelerator = Crosslinked Epoxy Adhesive

Case 1: Polyethylene flake + remelted/formed = Polyethylene thermoplastic

For this presentation we’ll detail the materials needed for the third case- glass fiber reinforced composites for pressure vessels.



are needed to see this picture. Working backward from crosslinked polyester

• Unsaturated Polyester Resin (1) which is derived from Maleic anhydride (2) which is derived from

butane (3) (& O2 & VPO catalyst) which is derived frombutene (4) (& H2 & Raney Ni catalyst) which is derived from

methanol (5) (& Zeolite catalyst) which is derived fromCO, H2, CO2

and Ethylene glycol (6) is which derived from oxirane (7) (& steam) is which derived from

ethylene (8) (& Ag and Al2O3 catalysts) which is derived from methanol

• Styrene (9) which is derived from ethylbenzene (10) (& Fe catalyst) which is derived from

benzene (11) (& Zeolite catalyst) which is derived from CO2, O2, H2, H2O

and ethylene (12) which is derived from methanol



are needed to see this picture. Working backward to the basic 12 chemicals

And as the reaction initiator

• Methyl ethyl ketone peroxide (13) which is derived from 2-butanone (14) which is derived from

2-butanol (15) which is derived frombutene

and hydrogen peroxide(16) which is derived fromsulfuric acid (17) which is derived from

SO2 (18) (& O2, H2O & Vanadium dioxide catalyst) which is derived fromGypsum thermal decomposition

and HCl (19) which is derived fromsulfuric 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.



are needed to see this picture. Summary: all polymer precursor chemicals

8 inorganic chemicals

15 Imported CatalystsMethanol Maleic AnhydrideEthene 2-ButanolPropene 2-Butanonen-Butene MEKPOEthylene oxide BenzeneGlycol CyclohexaneAcrolein EthylbenzeneAllyl alcohol StyreneGlycerol CumeneAcetic Acid Phenol3-Chloropropene AcetoneGlycerol dichlorohydrin Bisphenol ACalcium hydroxide 1,3-DinitrobenzeneEpichlorohydrin 1,3 DiaminobenzeneButane 1-butene

Sodium hydroxideChlorineSulfur dioxideSulfuric acidHydrogen chlorideAmmoniaNitric acidHydrogen peroxide

CuZnOZeoliteAgAuVanadium oxideRuPtIr(CO)2,I2

Raney NickelVPOMoCuClIon exchange resinTi based Ziegler catalyst

30 Organic polymer precursor 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




Cumene(2-Phenylpropane)

1-10 atm., O2

82 - 90oC, radical initiator

[Cumene Hydro-peroxide CHP] Phenol

60-70oC

H+,H20

CH3COCH3 To 8.

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.



are needed to see this picture. Aliphatic Organic Synthesis Sequence*

CH2=CH2

2.CO2 + CO

H2

1.methanol

To cumene 6.

CH3OH

ethene

To ethylbenzene 4.

HOCH2CH=CH2propene

MTO

CH3CH2CH=CH2

+CH3CH=CHCH3

1 and 2-butenes

H2 CH3CH2CH2CH3

butane

H2O, H2SO4

CH3CH2CHOHCH3

2-butanol

maleic anhydride

CH3CH2COCH3

Cu

2-butanone, MEK

HOOCOOCOOH CH3 CH2CH3

CH3CH2 CH3

MEKPO dimer

H2S2O8

Cl2 CH2ClCH=CH2

3-chloropropene

Cl2, H2O CH2-CHCH2Cl Oepichlorohydrin

To polyethylene 1.

Ag

3a.

CH2-CH2

Ooxirane

H2O HOCH2CH2OH ethylene glycol3b.

5a. 5b.

7a.

8a. 8b. 8c.

HOCH2CHOHCH2OH

glycerol

H2O2 ClCH2CHOHCH2Cl

glycerol dichlorohydrin4a. 4b. CaO

CO CH3COOH

Acetic acid 9.

CaO

CH3CH=CH2 2-propenol

HCl

HOAc4c.

6.

As solvent for polyethylene 1.As co-reactant for LDPE

CO, O2 CH3OCOOCH3

Dimethyl CarbonateCuCl, 130oC, 2000kPa

7/2O2, 400 - 480oC0.3 - 0.4 Mpa

CH=CH

O=C C=O

O

* Patent Pending



are needed to see this picture. Manufacturing the glass fiber

Glass fiber is the least energy intensive fiber to produce on Mars.

Three main types of fiber glass

1. C glass (uncommon) used in corrosive environments. It is a soda-lime-borosilicate composition

2. E glass used in printed circuit boards. Has the greatest number of components.

3. 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

Glasstype

SilicaSiO2

AluminaAl2O3

CalciumoxideCaO

MagnesiaMgO

BoronoxideB2O3

SodaNa2O

CalciumfluorideCaF2

otherminoroxides

E 54 14 20.5 .5 8 1 1 1

S 64 25 10 .3 1

C 66 4 13 3 5 8.5 1.3

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.



are needed to see this picture. 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



are needed to see this picture. 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



are needed to see this picture. Manufacturing Methods for Composites

Using pressure and elevated temperature to aid infiltration of matrix around fibers

1. Autoclave Cure - Best properties, but requires massive pressure vessel/oven

2. 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:

1. Filament winding

2. Open Mold processes

• Sprayup

• Hand layup

We will use filament winding and sprayup



are needed to see this picture. 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



are needed to see this picture. 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.



are needed to see this picture. Polyethylene Part Manufacture

Extrusion product lines are compact

• 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.



are needed to see this picture. Conclusions

• We have analyzed the requirements to establish a chemical processing and 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 and inorganic 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.



are needed to see this picture. Next Step: Design the Chemical Plant

Reaction Pressure vs Temperature Scatter Plot

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000 1200 1400

Temperature deg C

Pressure bar

Gypsum to SO2

KAAP Ammonia Process

Methanol process

HDPE and LLDPE

ethylbenzene

Styrene

Benzene

• 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



are needed to see this picture. 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.

Aug-6-05F. Crossman and R. Milligan1 Polymer Synthesis & Manufacturing Systems Frank Crossman and...

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