AN ANALYTICAL APPROACH TO TOXIC SUBSTANCE REPLACEMENT IN SUPPORT OF POLLUTION PREVENTION
Emission Reduction Research Center, New Jersey Institute of Technology, University Heights, Newark, NJ, 07102-1982, Phone: (201)596-5844
In support of pollution prevention and in accordance with Executive Order 12856 concerning pollution prevention, all federal agencies must comply with the Toxic Release Inventory (TRI) chemical release reduction and pollution prevention planning. The inventory lists hundreds of chemicals and choosing those to replace and finding actual replacement chemicals or procedures is not always clear. This study focuses on an analytical approach to this problem by understanding the application of ethanol. Ethanol is a volatile organic compound (VOC) used as a solvent in ammunition manufacturing. Ethanol's use as the solvent for shellac in a primer lacquer is characterized in the laboratory. Due to interest in substituting acetone for ethanol, an acetone-based primer lacquer is fabricated and tested in comparison to its ethanol counterpart. The results form the basis for broader application and chemical change.
Keywords: ethanol, solvent, viscosity, surface tension
Project Definition and Objectives
Executive Order 12856 concerning pollution prevention states that all federal facilities must comply with the Toxic Release Inventory (TRI) chemical release reduction and pollution prevention planning requirements of the Emergency Planning and Community Right-to-Know Act (EPCRA). To achieve compliance with these requirements, the Army has taken several actions. They have started procedures that facilitated the gathering of data necessary to report on TRI emissions. Moreover, they have traced to the source significant portions of the TRI reportable emissions and transfers. Knowing the source of the materials facilitates changes in operations that lead to reduced levels of use. The Army has instituted significant changes in some operations that include improved management of potential leaks, reduction in spills, improved material handling, and use extension of some materials. These changes have already been responsible for reductions in the TRI-reported emissions.
A larger challenge is further reductions in use and emission of hazardous materials in manufacture and maintenance of military-related products such as armament and weapon systems. Much of the challenge lies in the necessity of assuring performance and long shelf life of military articles that include bullets, guns, aircraft, and other critical items. The military has evolved a system of military specifications (MILSPEC) and related requirements that carefully specify materials to be used and practices to be employed in the manufacture and maintenance of performance critical items. The specifications assure appropriate performance levels through the military specifications. An effort is underway to make changes in the approach to military specifications with a greater effort to require levels of performance to be assured by a manufacturer without requiring adherence to the current material and process specifications. The impact of that change cannot be evaluated for a few more years. In the meantime, changes in processes and materials that appear to have potential to lead to pollution prevention opportunities are hampered because of the seemingly rigid military specifications that currently apply.
In the course of this research program, opportunities were identified to reduce or eliminate the use of ethanol in Army operations. Ethanol has several uses in both military and civilian applications. This chemical emerged from the evaluation of military requirements not necessarily because it represents the largest volume or the greatest potential risk. Rather, it and the processes that currently require its use are illustrative of the requirements and systematic approaches that can be used to identify and qualify changes that result in reduction of use and emissions. Ethanol is a hazardous material used in Army production processes that should be substituted for, if at all possible, with materials that are environmentally benign.
The methodology for elimination or reduction ethanol in manufacturing is of principal interest. The methodology is an analytical approach to define the substance based on performance criteria in its respective process. A review of the process requiring this hazardous substances is essential so that opportunities for substitutions can be identified. The performance requirements of DOD must still be met when the new procedures are in place.
Ethanol as a Toxic Chemical
Ethanol's primary industrial uses are as a solvent and as a fuel additive. Its foremost hazard to the environment is as a volatile organic compound (VOC) with accompanying impact on air quality. Flammability, reactivity, and toxicity are the safety issues. Liquid ethanol can react vigorously with oxidizing materials. Ethanol poisoning and intoxication are almost always limited to ingestion as opposed to vapor inhalation as would be encountered in a typical industrial environment.
Ethanol's use as the solvent for shellac in a primer lacquer is characterized in the laboratory. Due to interest in substituting acetone for ethanol, an acetone-based primer lacquer is fabricated and tested in comparison to its ethanol counterpart.
Shellac Properties Review
Shellac is the purified product of the hardened resinous secretion of a parasitic insect on certain trees and bushes of India, Myanmar, and Thailand. The shellac resin is hard, tough, and non-toxic and produces water-resistant films.
Since shellac is a natural product of animal origin, it differs somewhat from one source to another. Average property values are questionable since early studies neglected temperature and humidity effects. The best solvents for shellac are the lower alcohols, methyl and ethyl, followed by amyl alcohols, glycols, and glycol ethers. Shellac is insoluble in esters, ethers (except glycol ethers), hydrocarbons, chlorinated solvents, and water. It can be dispersed in water with soda ash, borax, ammonia, morpholine, or triethanolamine.
Shellac contains approximately 67.9% carbon, 9.1% hydrogen, and 23.0% oxygen for an empirical formula of C4H6O. Based on a molecular weight of about 1000, the average molecule has the formula C60H90O15. It contains one free-acid group, three ester linkages, five hydroxyl groups, and possibly a free or potential aldehyde group. This is indicated by the acid value, hydroxyl value, saponification value, and carbonyl value. Its ionization constant is 1.8X10-5.
Ethanol Properties Review
Ethanol is a versatile oxygen-containing organic chemical. Its unique combination of properties make it useful as a solvent, a germicide, a beverage, an antifreeze, a fuel, and a depressant. It is also a chemical intermediate for other organic chemicals such as glycol ethers, ethyl acetate, and vinegar. Under normal conditions it is a volatile, flammable, clear, colorless liquid. Liquid ethanol can react vigorously with oxidizing materials.
Ethanol's physical and chemical properties are primarily dependent on the hydroxyl group. The group gives polarity to the molecule and gives rise to intermolecular hydrogen bonding. These properties account for the differences between the physical behavior of lower molecular weight alcohols and hydrocarbons of equivalent weight. The hydroxyl group provides the majority of the chemical properties including dehydration (e.g., ether formation), oxidation, dehydrogenation, and esterification.
Acetone Properties Review
Acetone, also called 2-propanone or dimethyl ketone, is the simplest and most important ketone. It is a colorless, flammable liquid that is miscible with water and most organic solvents. Its primary uses are as a solvent and as a reaction intermediate for the production of other compounds which themselves are solvents or reaction intermediates.
Acetone occurs naturally in the environment and is biodegradable. It has comparatively low acute and chronic toxicity as compared to other organic solvents. High vapor concentrations produce anesthesia and may irritate the eyes, nose, and throat. Generally, there are no injurious effects other than skin irritation or headaches from prolonged exposure.
Acetone is of interest mainly because it was removed from the TRI and may be substituted for ethanol as a solvent in some circumstances. The testing of acetone in place of ethanol as the solvent for cut shellac is of principal importance for this work.
PRIMER LACQUER SOLVENTS-ETHANOL AND ACETONE
Problem Definition and Background
In response to EPCRA, Picatinny Arsenal, the military weapons research and development facility in New Jersey, is developing new ammunition that is manufactured in an environmentally appropriate way. This "Green Bullet" program aims to find substitutes for the hazardous substances used to make, clean, and paint bullets. These new bullets could reduce the environmental problems at shooting ranges nationwide as well as at the manufacturing plants.
Ethanol, a VOC in ammunition manufacturing, is used as a solvent with shellac. A mixture of ethanol, shellac, and purple dye is used to seal primer into the primer cup at the rear of the bullet. This mixture, called the "primer lacquer" or "purple primer lacquer" is the subject of this work.
The ammunition product drawings require the primer lacquer to prevent primer dusting, pellet cracking, and water entry. Primer dusting is evaluated via a "rotap" test. Additional requirements are to be visibly present (quality control), be easily processed, not diminish barrel life (non-corrosive), not degrade ballistic performance, no ozone depleting compounds (ODC), and low VOC. A VOC level of less than 5 lb/gal is desirable.
Drying time is another aspect. The primer lacquer must dry to the touch in 15 minutes and be completely dry within one hour. The aim is to form a crust over the primer. These conditions must be met when searching for a substitute.
The equipment and machinery used in applying the primer lacquer are considered a constant in this problem due to high capital costs for replacement. It is undesirable to purchase new equipment and massively change assembly-line procedures in this particular case. Therefore, any substitute should be applied with existing machinery.
The current equipment uses brass pins, or punches, to apply the primer lacquer. The punches are lowered mechanically into a reservoir and then placed over the primer cups where a drop is placed into the cup. The cup already contains the primer and a paper covering, also called a foil covering. The primer lacquer must spread over the paper, penetrate the paper somewhat to grip the primer, and seal to the brass primer cup. Clean operations are essential for safety and bullet integrity.
Once the primer lacquer is in place, an anvil is inserted into the cup. The anvil keeps the entire cup intact and plays a role in the actual firing process. A satisfactory cup must have the anvil properly seated. The primer lacquer can adversely affect this seating by making the anvil cocked, loose, high, or deep.
Based on these requirements, testing of the primer lacquer may characterize what approaches to chemical or procedural change could fulfill the requirements. What are the significant properties for foil penetration and crust formation? Ammunition manufacturing guidelines use solids content as the method of measuring the primer lacquer's ability to perform. However, performance may or may not depend on solids content depending on the make-up of the primer lacquer or any replacement. With the current application technique, it is suggested that primer lacquer viscosity and surface tension are key indicators of performance.
Because of the method of transfer of the lacquer or any replacement from the process tank to the primer cup, the characteristics of the fluid are important, in addition to whatever product performance characteristics are required. An assembly of pins is dipped into the tank and it is expected that each pin will take from the tank one drop of lacquer of sufficient size and viscosity to withstand the trip to the primer cup without falling off. Moreover, the quantity must be sufficient to provide the needed coverage of the top of the primer cup.
As a result of this research program, it is clear that a search for modification or replacement of the presently used lacquer will require careful consideration of the requirements for the transfer operation as well as any performance characteristics.
Viscosity and surface tension are measured directly in laboratory testing and are recommended as benchmarks in the search for substitutes.
It is this analytical approach that is central to finding replacement candidates for hazardous substances. Measuring the appropriate performance characteristics of what works and using those results as a search aid will greatly reduce the field of choices, quicken the search, and increase the probability of success.
Primer Lacquer Composition
The standard formula for the primer lacquer is 13 gallons of four-pound cut shellac, 39 gallons of denatured ethyl alcohol (ethanol), and one gallon of purple dye. The base formula provides 9.4% solids. These components are mixed into a 55-gallon mixing drum until thoroughly blended (about 30 minutes). The color is checked and more dye mix is added as necessary to achieve the "appropriate" color intensity while maintaining transparency. Production experts define the "appropriate" color.
Four-pound cut shellac, by definition, is made using four pounds of dry shellac mixed with one gallon of ethanol. Therefore, the VOC component comes from the already-mixed shellac and the additional ethanol. This mixture (plus or minus one gallon of ethanol) has been used as far back as the 1940s without appreciable change. The reasoning behind using the aforementioned requirements (e.g., solids content as a performance characteristic) has been lost. The system works as is, so there was little if any reason for change, until EPCRA.
An Army ammunition manufacturing facility is testing an acetone primer lacquer as a substitute. Its formulation is exactly as above with 39 gallons of acetone substituted for the 39 gallons of ethanol. This maintains the solids content of the lacquer-the property believed important by the facility.
The aim of the laboratory work is to characterize the primer lacquer's viscosity and surface tension. The acetone lacquer's viscosity is measured and compared to that of the primer lacquer. Finally, a solubility experiment determines the ability of the shellac to stay in solution in the acetone primer lacquer. Sustaining a solution is integral to the manufacturing line performance.
Both dynamic (or absolute) viscosity (µ) and kinematic viscosity () are measured as they differ by only the factor of density ():
µ = (1)
The Cannon-Fenske viscometer gauges kinematic viscosity as a function of time. Density is measured by weighing (or massing) a known volume.
The drop-weight method employs the stalagmometer to gauge surface tension. It is the best general method when considering accuracy and speed compared to the capillary rise or ring methods. Additionally, it only requires a small quantity of liquid.
To ensure the proper amount of shellac is placed in the primer cup, it is important for the lacquer to stay in solution. The solubility test is approached by two routes. The first is to add acetone to four-pound cut shellac until shellac precipitates out or the solution is not maintained. The second is to add ethanol to the acetone primer lacquer until the mixture becomes a solution.
Viscosity Theory and Determination
The viscosity of a fluid is a measure of that fluid's resistance to flow when acted upon by an external force such as a pressure differential or gravity. Most viscous fluids flow more easily at higher temperatures. For a Newtonian fluid, shear stress () is proportional to the velocity gradient, or rate of strain, (dv/dy) by the factor of dynamic viscosity (µ):
= µdv/dy (2)
which is known as Newton's law of viscosity.
Dynamic viscosity has units of centipoise (cp) which have dimensions FT/L2. Kinematic viscosity units are centistokes (cs) which have dimensions L2/T.
The Cannon-Fenske viscometer is a capillary-flow method for determining the kinematic viscosity. The volume rate of flow is measured through a tube of known circular cross section and length. Manipulating equation (2), the dynamic viscosity equation becomes:
µ = [(r4gh)/8Vl]t (3)
where r is the tube radius; g is gravity; h is the difference in height of the two reservoirs; V is the fluid volume; and l is the tube length. By using equations (1) and (3), this number divided by the density will yield the kinematic viscosity. The quantity in square brackets represents a constant for a given viscometer, call it C. Therefore, kinematic viscosity can be obtained by:
= Ct (4)
which is the equation used by Cannon-Fenske.
The procedure for performing viscometry tests uses the instructions from the Cannon Instrument Company of State College, Pennsylvania, which are based on ASTM D 445. Two sizes are used for verification purposes. Size 100 has C=0.015 centistokes/second (cs/s) and is recommended for viscosity ranges of 3 to 12 cs. This viscometer provides the primary data since the viscosity of the primer lacquer is assumed to be in that range based on the lacquer constituents (assumption verified by actual test). Size 200 has C=0.1 cs/s and is recommended for a 20 to 80 cs range. Essentially, the viscometer is charged, the fluid flows due to gravity, and the time to flow between two points is clocked. The viscometer constants were verified by timing a known substance, water, and comparing those values to the water viscosity of one cs. Viscosity results are accurate to two significant figures.
Although the densities of the two primer lacquers are similar, dynamic and kinematic viscosities differ considerably. Difficulties were encountered in keeping the acetone primer lacquer in solution.
Surface Tension Theory and Determination
The molecules at the surface of a liquid are subject to the attractive forces of the interior molecules. A resultant force, whose direction is in a plane tangent to the surface at a particular point, acts to make the liquid surface as small as possible. The magnitude of this force acting perpendicular to a unit length of line in the surface is called the surface tension. Surface tension is a property of interface. It has units of dynes/cm, dimensions F/L.
In the drop-weight method, a drop forms at the end of the stalagmometer and the boundary line is the outside perimeter. When the drop just detaches itself, the downward force on the drop is equal to the force acting upward. Surface tension decreases as the temperature rises and is virtually unaffected by changes in area, pressure, or volume.
The procedure for performing the surface tension tests uses the Traube Stalagmometer directions from SGA Catalog No. S-9725. This stalagmometer is a pipette with a broad, flattened tip which permits large drops of reproducible size to form slowly and finally drop. The surface tension calculation is based on the number of drops which fall, the density of the sample, and the surface tension of water which is used as a reference liquid for factory standardization of the stalagmometer.
The water drop number engraved on the stem of the pipette indicates the number of drops of distilled water at 25oC which fall from the tip during passage of a particular volume included between corresponding marks on the two engraved scales. Drop weights are proportional to surface tension. The relationship for calculating surface tension in terms of drop numbers is:
S = [ (Sw)(Nw)() ]/[ (N)(w) ] (5)
= [ (72.0)(Nw)() ]/(N) (6)
where S is the surface tension of the sample (dynes/cm); Sw is the surface tension of the reference liquid (water); N is the number of drops of the sample; Nw is the water drop number engraved on the stalagmometer; is the density of the sample (g/ml); and w is the density of water.
The factory determination of the water drop number for each stalagmometer is made at 25oC. This is the ideal temperature at which to conduct the trials. However, little error is involved when measurements are made at another temperature. In this case, (72.0)(Nw) in the numerator of equation (6) is not changed. Since the water drop number is inversely proportional to the surface tension of the water, the product of (Sw)(Nw) remains essentially independent of any changes in the surface tension caused by temperature alterations. Therefore, without involving much error, the sample drop number and density for any temperature may be substituted into equation (6) along with the water drop number and water surface tension for 25oC.
The basic steps of the procedure are drawing the fluid, counting the drops (No) between the upper and lower graduations (x and y in mm), and calibrating the capillary scale calibration (c in mm/drop). Reading the graduations accurately and maintaining a slow drop flow are the key aspects of this test. The actual drop number, N, is calculated as follows:
N = No + (x-y)/c. (7)
The fractional part of a drop, given by the second part of equation (7) may be either positive or negative.
The stalagmometer technique was verified by measuring a known substance, ethanol, and comparing that value to the known value of 23.1 dynes/cm at 25oC. Surface tension results are accurate to one decimal place. A total of four trials are performed, two each on two different stalagmometers, for consistency of results.
The surface tension for the acetone primer lacquer could not be measured due to its incapacity to stay in solution.
The primer lacquer must be able to stay in solution over a reasonable period of time, at least a few hours. This is important so that an accurate amount of shellac can be delivered to the primer cup. If a lacquer cannot stay in solution, an unknown amount is delivered to the cup and performance will be at issue.
The solids contained in the acetone primer lacquer precipitate out over a short period of time. This time is observed to be from less than one hour down to a few minutes making this lacquer inappropriate for an assembly line process.
The question arises as to how much (or how little) acetone will take the shellac out of solution. As previously noted, this solubility test is approached by two routes. The first is to add acetone to four-pound cut shellac until shellac precipitates out or the solution is not maintained. The second is to add ethanol to the acetone primer lacquer until the mixture becomes a solution.
In the first case, acetone is added one ml at a time to five ml of four-pound cut shellac. After only three ml are added, the mixture is no longer a solution. Compare this three ml addition to 15 ml that would normally be added to five ml of the cut shellac for the acetone primer lacquer. Based on this trial, the acetone primer lacquer not only comes out of solution, but it likely is never in solution.
In the second case ethanol is added one ml at a time to five ml of the acetone primer lacquer. Since solids are already precipitated in the lacquer, the question is how much ethanol is required to place the mixture back into a solution. The results are that no addition of ethanol could take the precipitate out. The mixture could not be brought to a solution.
Both tests demonstrate that shellac simply is not sufficiently soluble in acetone to allow the mixture to be used in this manufacturing step.
RESULTS AND DISCUSSIONS
The kinematic viscosity of the acetone primer lacquer is 0.93 cs as compared to 3.1 cs for the purple primer lacquer. This represents about a 70% decrease in viscosity. The two lacquers have similar densities; hence, the dynamic viscosities are different as well. This viscosity difference is not surprising since ethanol and acetone have different viscosities themselves as noted in Table 1. Surface tension for the acetone primer lacquer is virtually meaningless because it is a suspension, not a true solution. However, it is worth noting that acetone and ethanol have similar surface tensions.
Based on these results, it is unlikely that the acetone primer lacquer will deposit the same amount of shellac into the primer cup as does the current purple primer lacquer. In fact, the amount of shellac delivered by the acetone primer lacquer will change depending on how long the mixture has been sitting in the reservoir without thorough stirring.
Since the solubility tests confirm that shellac is not soluble in acetone, it is highly unlikely that acetone would be an appropriate substitute for ethanol in the primer lacquer. This is true independent of viscosity or surface tension.
Among the many factors that may not be reflected in the price of a solvent are its removal and disposal costs. The solids precipitating out of the acetone primer lacquer yield an additional waste stream, the costs for which must be accounted.
It should be noted that a test of the acetone primer lacquer was conducted by an Army ammunition manufacturing facility. The rounds were manufactured under "ideal" conditions. The mixture was shaken, the pins dipped, and the acetone primer lacquer delivered. In other words, because of the short time of the test, actual assembly line manufacture may not be adequately represented. Expert inspectors stated, from visual inspection, that the correct amount of shellac was delivered to the primer cup and it spread appropriately. The subject ammunition rounds were fired successfully.
CONCLUSIONS AND RECOMMENDATIONS
Recommended Actions for Primer Lacquer
The results of this work extend those obtained at the facility. This brings up many considerations. Does the visual inspection accurately depict the solids content of the primer lacquer delivered, or simply the amount of the dye that is delivered? If the actual shellac delivered to the cup is unknown, what is the relationship between the amount of shellac and the firing of the rounds. Will there be long-term storage effects? Perhaps most importantly, is the quality control criteria currently employed sufficient to monitor quality if there are changes in manufacturing procedures? What was the purpose of these criteria fifty years ago and is it equally applicable today?
A critical review of military specifications and drawings, their purpose, and their basis for continuance is necessary. Pollution prevention requires environmentally conscious decisions early in the design stage. If the eventual replacement for the primer lacquer requires considerable equipment and process change, significant cost may be accompanied. Whatever future action is followed, the removal of hazardous substances from the environment should be approached in a systematic, analytical manner.
Suggestions for Further Study
The paint and coatings industry is constantly looking for improvements in film (coating) development. Improvements include reducing hazards to the environment and complying with EPCRA.
Thermoplastic systems, including lacquers and latex-based systems, may provide some avenues for improved coatings. A useful definition of a solid film used in thermoplastic systems is that it does not flow significantly under the pressures to which it is subjected during testing or use. Therefore, a film can be defined as a solid under a set of conditions by stating the minimum viscosity at which flow is not observable in a specified time interval.
Viscosity can be used to measure dry to the touch. If the viscosity is greater than about 106 cp, it is dry to the touch. The viscometers used in this work would be inappropriate for such high viscosities. However, the falling-ball viscometer or an electronic viscometer may be useful in this case. They are the simplest methods for determining viscosity.
Studies using aqueous-based solvents may be explored. Some experimental studies performed by an Army ammunition manufacturing plant to replace the primer lacquer did not identify an appropriate substitute. The problems encountered were excessive dry time, reduced primer sensitivity, and poor absorption into the foil. Wetting ability is a major limitation of aqueous-based solvents since the surface tension of water is much greater than that of organic solvents. This wetting ability is important for a primer lacquer since the solvent must wet the shellac, the foil, and the brass.
Toxic Chemical Ranking
The development of methodologies to initially screen and rank toxic chemicals is of interest. This section mentions some of the other work done in this general area. These methodologies may be of use in future research.
Bosch proposes a quantitative hazard analysis methodology to screen and prioritize plants as opposed to actual processes. The procedure defines an organization based on the hazard potential inherent in each plant's use of toxic, flammable, and explosive chemicals. The hazard potential is a function of the type and severity of chemical hazards present and of the quantity manufactured, consumed, or stored on-site. Information necessary to determine the hazard potential is available with either direct or indirect knowledge of plant operation. The methodology may also be modified to account for specific organizational needs.
OSHA uses the concept of threshold quantity for highly hazardous chemicals to determine the application of their rules to a specific site. Bosch's methodology conducts a more comprehensive review of chemical use than one based on OSHA rules. Chemical threshold quantities may be based on either the maximum quantity stored on-site or the total quantity processed in one year, provided a consistent basis is used for all evaluated plants and chemicals. Chemicals with multiple hazards are categorized according to flammability, reactivity, and toxicity.
Horvath, et al., of Carnegie Mellon University contrast the one-to-one ranking of the TRI with a ranking based on relative toxicity, using threshold limit value indices. The weighting scheme is a first step in correcting the "equality" of toxic chemicals in the TRI. This methodology addresses basic problems with the TRI. These problems are TRI inaccuracy, discharge focus as opposed to environmental fate, and simplistic interpretation of TRI data. Toxic weighting systems are generally limited by lack of data and subjective input requirements. However, this toxicity-based measure can be a useful first step in modifying the TRI.
Ammann, et al. list seven steps to find the best compliance strategy which can be used as a starting point for toxic substance identification. The engineer should consider not only the present permit limitations, but also any future regulatory requirements that could arise. The steps are (1) analyze pollutant sources; (2) make a pollutant balance; (3) develop control schemes; (4) consider process changes; (5) make a rough cost estimate; (6) check on compliance; and (7) analyze the economics.
Funding for this research was provided by the Northeast Hazardous Substances Research Center.
Alloway, Kristen. 6 Nov 1996. "Army Getting the Lead Out of Its Ammo for Environment's Sake." The Star-Ledger. 19, 24.
Ammann, Paul R., G.S. Koch, M.A. Maniatis, and K.T. Wise. 1995. "The Best Approach to Environmental Compliance." Chemical Engineering. 102(2): 104-6.
Bosch, William W. 1992. "Identify, Screen and Rank Toxic Chemicals." Chemical Engineering Progress. 88: 33-9.
Daniels, F., J.W. Williams, P. Bender, R.A. Alberty, C.D. Cornwell, and J.E. Harriman. Experimental Physical Chemistry. 1970. 7th ed. McGraw-Hill NY. 157-66, 359-64, 497-8.
Executive Order 12856. 1993. "Federal Compliance with Right-to-Know Laws and Pollution Prevention Requirements." National Defense Center for Environmental Excellence.
Horvath, Arpad, C.T. Hendrickson, L.B. Lave, F.C. McMichael, and T.S. Wu. 1995. "Toxic Emissions Indices for Green Design and Inventory." Environmental Science & Technology. 29(2): 86A-90A.
Kirk-Othmer. 1994. Encyclopedia of Chemical Technology. New York: Wiley. 4th ed. 1: 176-92. 6: 669-708. 9: 812-49. 20: 737-46.
Small Caliber Ammunition Branch, Close Combat Armaments Center. 1995. 5.56 mm Product Drawings.
Sullivan, Thomas F.P. 1995. Environmental Law Handbook. Rockville, MD: Government
Table 1. Typical properties of ethanol and acetone (kirk-Othmer)
|Boiling Point, oC||78.3||56.3|
|Autoignition Temp, oC||423||538|
|Flash Point, oC||14||-19|
|Dynamic Viscosity, cp||1.17||0.32|
|Surface Tension, dynes/cm||23.1
|CAS Registry Number||[64-17-5]||[67-64-1]|
Table 2. Purple primer lacquer viscosity
Size 100 viscometer, C=0.015 cs/s, Temp=21.2oC
|Trial||t (s)||=Ct (cs)|
|average = 3.1|
Table 3. Purple primer lacquer viscosity
size 200 viscometer, C=0.1 cs/s, Temp=19.0oC
|Trial||t (s)||=Ct (cs)|
|average = 2.9|
A 50 ml volume of primer lacquer weighs 42.0 g. Therefore, = 42.0 g/50ml = 0.84 g/ml. Using = 3.1
cs, µ = 3.1 cs 0.84g/ml = 2.6 cp.
Table 4. Acetone primer lacquer viscosity
size 100 viscometer, C=0.015 cs/s, Temp=19.8oC
|Trial||t (s)||=Ct (cs)|
|average = 0.93|
Table 5. Acetone primer lacquer viscosity
size 200 viscometer, C=0.1 cs/s, Temp=19.5oC
|Trial||t (s)||=Ct (cs)|
|average = 0.94|
A 50 ml volume of acetone primer lacquer weighs 40.9 g. Therefore, = 40.9 g/50 ml = 0.82 g/ml.
Using = 0.93 cs, µ = 0.93 cs 0.82 g/ml = 0.75 cp.
Table 6. Purple primer lacquer surface tension test
Temp=20.5oC, =0.84 g/ml
|average = 23.1|