Apparatus for germ reduction of a fluid and a process for use thereof

Abstract

A static devolatilization apparatus (1) for germ reduction of a fluid is disclosed. The apparatus (1) comprises a housing (10), an inlet (12), an outlet (14), a fluid-contacting surface (20) comprising a biocide (22) embodied to reduce the germ count of the fluid (2), wherein the fluid-contacting surface (20) is a fluid-contacting surface (20) of a static mixing element (30). The present invention further relates to a process for reducing the germ count of a fluid containing germs (2) using the apparatus (1) and also to the use of the apparatus (1) in the germ reduction of fuel oil, of food products, or water decontamination, preferably decontamination of waste water, industrial process water, or the treatment of drinking water.

Claims

1. An apparatus for germ reduction of a fluid comprising: a housing; an inlet; an outlet; and a fluid-contacting surface comprising a biocide embodied to reduce the germ count of the fluid; wherein the fluid-contacting surface is a fluid-contacting surface of a static mixing element, and wherein the fluid-contacting surface comprises a guanidine or a derivative thereof being selected from the group consisting of: (i) a polymeric guanidine according to the general formula ##STR00001## wherein R1 and R2 are independently of each other H, [C(NH)NHR3], or an aliphatic, cycloaliphatic, araliphatic or aryl organic group, or an acyl group comprising such an organic group; R3 is H or an aliphatic, cycloaliphatic, araliphatic or aryl organic group, or an acyl group comprising such an organic group; and I is anion and n greater than or equal to two; (ii) a polymer compound selected from the group consisting of polyethylene, propylene, polyamide, PVDF, polyurethane, and polycarbamides compounded with the polymeric guanidine described above; and (iii) a polymer compound selected from the group consisting of polyamide, polyethylene, fluoropolymer, and polyurethane compounded with guanidine or a derivative thereof wherein the fluid-contacting surface does not substantially release the biocide to the fluid such that the concentration of biocide in a fluid contacting the fluid-contacting surface is less than 50 ppm.

2. The apparatus of claim 1, wherein the fluid-contacting surface comprises a biocide-containing polymer.

3. The apparatus of claim 2, wherein the biocide-containing polymer is a copolymer.

4. The apparatus of claim 3, wherein the static mixer element contains biocide only in a surface region encompassing the fluid-contacting surface.

5. The apparatus of claim 2, wherein the biocide-containing polymer is a polymer compound.

6. The apparatus of claim 1, wherein the static mixer element contains biocide only in a surface region encompassing the fluid-contacting surface.

7. A process reducing the germ count of a fluid containing germs using the apparatus of claim 1, the process comprising the steps of: feeding the fluid containing germs to the apparatus via the inlet, treating the fluid containing germs on the fluid-contacting surface comprising a biocide in order to form a fluid having a reduced germ count, removing the fluid having a reduced germ count from the apparatus via the outlet.

8. The process of claim 7, wherein a residence time in the apparatus is less than 600 s.

9. The process of claim 7, wherein a temperature of the fluid in the apparatus is between 0 and 200 C.

10. The process of claim 7, wherein a germ count of the fluid is reduced in the process by log 0.5 to 7.

11. The process of claim 7, wherein a pressure of the fluid in the process is less than or equal to 100 bar.

12. The process of claim 7, wherein a ratio of an active surface to a volume of the apparatus is more than 50 m2/m3.

13. The process of claim 7, wherein a viscosity of the fluid in the process is less than 1000 Pa s.

14. The process of claim 7, wherein a pressure loss of the fluid is less than 1 bar.

15. A method for use of the apparatus of claim 1 comprising the steps of providing the apparatus of claim 1 and using it in a process of germ reduction of fuel oil, of food products, or water decontamination by introducing a fluid to the inlet.

16. The apparatus of claim 1, wherein the fluid-contacting surface does not substantially release the biocide to the fluid such that the concentration of biocide in a fluid contacting the fluid-contacting surface is less than 15 ppm.

17. The apparatus of claim 1, wherein the fluid-contacting surface does not substantially release the biocide to the fluid such that there is no detectable level of biocide in a fluid contacting the fluid-contacting surface.

18. The apparatus of claim 1, wherein the wherein the fluid-contacting surface is a liquid contacting surface that does not substantially release the biocide to the liquid such that the concentration of biocide in a liquid contacting the fluid-contacting surface is less than 50 ppm.

19. An apparatus for germ reduction of a fluid comprising: a housing; an inlet; an outlet; and a fluid-contacting surface comprising a biocide embodied to reduce the germ count of the fluid; wherein the fluid-contacting surface is a fluid-contacting surface of a static mixing element, and wherein the fluid-contacting surface comprises a guanidine or a derivative thereof being selected from the group consisting of: (i) a polymeric guanidine according to the general formula ##STR00002## wherein R1 and R2 are independently of each other H, [C(NH)NHR3], or an aliphatic, cycloaliphatic, araliphatic or aryl organic group, or an acyl group comprising such an organic group; R3 is H or an aliphatic, cycloaliphatic, araliphatic or aryl organic group, or an acyl group comprising such an organic group; and I is anion and n greater than or equal to two; (ii) a polymer compound selected from the group consisting of polyethylene, propylene, polyamide, PVDF, polyurethane, and polycarbamides compounded with the polymeric guanidine described above; and (iii) a polymer compound selected from the group consisting of polyamide, polyethylene, fluoropolymer, and polyurethane compounded with guanidine or a derivative thereof wherein the fluid-contacting surface does not substantially release the biocide to the fluid such that the concentration of biocide in a fluid contacting the fluid-contacting surface is less than 50 ppm, and wherein the static mixer element comprises a plurality of layers in contact with one another, each layer bounding flow channels for the fluid, the axes of which are substantially parallel to the corresponding layers, the longitudinal axes of at least two flow channels of each layer being parallel and inclined to the longitudinal axes of at least some of the flow channels of an adjacent layer or layers, and at least some of the flow channels of each layer being arranged to communicate with flow channels of an adjacent layer or the static mixer element comprises one mixer element in the form of crossed webs disposed at an angle with a tube axis, the webs being disposed in at least two groups, the webs of any one group of elements extending substantially parallel to one another and the webs of one group crossing the webs of the other group.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail hereinafter with reference to various embodiments of the invention as well as to the drawings. The schematic drawings show:

(2) FIG. 1 shows a schematic view of an embodiment of an apparatus for germ reduction of a fluid according to the invention.

(3) FIG. 2 shows a schematic view of an embodiment of the apparatus of the invention in the form of a multitube apparatus.

(4) FIG. 3 shows a schematic view of a more specific embodiment of the apparatus of FIG. 2 in which the static mixing elements are helical static mixing elements.

(5) FIG. 4 shows a schematic view of another more specific embodiment of the apparatus of FIG. 2 in which the static mixing elements are crossed web static mixing elements.

(6) FIG. 5 shows an alternative embodiment of the apparatus of the invention in the form of a column filled with packing elements.

(7) FIG. 6 shows an embodiment of a general formula (A) for polymeric guanidines suitable for use in the present invention.

(8) FIG. 7 shows example data for the reduction in germ count obtained by an embodiment of the apparatus of the invention in a process having a residence time of 5 s.

(9) FIG. 8 shows example data for the reduction in germ count obtained by other embodiments of the apparatus of the invention in a process having a residence time of 10 s.

(10) FIG. 9 shows the favourable stability against migration of the biocide out of an embodiment of a static mixing element coated with a fluoropolymer-based compound of the biocide

DETAILED DESCRIPTION OF THE INVENTION

(11) FIG. 1 shows a schematic view of an embodiment of an apparatus for germ reduction of a fluid 2 according to the invention, which as a whole is labeled with reference number 1. The apparatus 1 is not specifically limited as to form, shape, construction or composition unless specifically indicated otherwise. The apparatus 1 comprises: a housing 10 an inlet 12 an outlet 14 a fluid-contacting surface 20 comprising a biocide 22 embodied to reduce the germ count of the fluid 2,

(12) wherein the fluid-contacting surface 20 is a fluid-contacting surface 20 of a static mixing element 30.

(13) The fluid 2 to be treated is not specifically limited and may be liquid or gas phase, preferably liquid phase. Example fluids 2 include air, water, aqueous solutions, fuel oil, liquid food products, and beverages.

(14) Static mixing elements 30 and static mixers and their construction and operation are well known in the art, for example, as disclosed in Handbook of Industrial Mixing: Science and Practice, edited by E. L. Paul, V. A. Atiemo-Obeng, S. A. Kresta, published by John Wiley and Sons in 2004 (ISBN 0-471-26919-0). Unless specifically indicated otherwise, conventional construction materials and means, as well as components and auxiliaries, may be used for the apparatus 1, and the apparatus 1 may be operated in a static mixing process in a conventional manner using conventional process parameters such as operating temperatures, operating pressures, and residence times as known in the art. For example, these cited reference textbooks disclose a variety of conventional preheaters, distributors, manifolds, internals, pumps, and valves for use with static mixing elements 30 in static mixers and other equipment.

(15) The static mixing element 30 is not specifically limited, and it is generally a baffle, typically helical in shape, contained in the typically cylindrical (tube) or squared housing 10. Suitable static mixer elements 30 will fulfill the function of providing a fluid-contacting surface 20 for enabling a contact between the biocide 22 and the fluid to be treated. In order to fulfill this function, the static mixer element 30 will have a void fraction of greater than 50, preferably 65, more preferably 70%. The void fraction in the present application is defined as the ratio of the free volume available for fluid to the working volume of the apparatus encompassing the static mixer element.

(16) In one embodiment the elements are helical or pseudo-helical and are arranged in a series of alternating left and right hand 180 degree twists. The elements split the fluids entering in two streams and than rotate them through 180 degrees. In another embodiment the static mixer element consists of intersecting corrugated plates and channels that encourage rapid mixing in combination with plug flow progression.

(17) Suitable static mixer design types include the corrugated plate, wall-mounted vanes, cross-bar, and helical twist types. Specific suitable static mixers for use with the invention include the Sulzer Chemtech SMX and SMX Plus, SMV static mixers.

(18) Suitable static mixer elements 30 include those disclosed in GB1373142 (A), U.S. Pat. No. 3,918,688 (A), and GB2061746 (A). In one embodiment, the static mixer element 30 comprises a plurality of layers in contact with one another, each layer bounding flow channels for the fluid, the axes of which are substantially parallel to the corresponding layers, the longitudinal axes of at least two flow channels of each layer being parallel and inclined to the longitudinal axes of at least some of the flow channels of an adjacent layer or layers, and at least some of the flow channels of each layer being arranged to communicate with flow channels of an adjacent layer.

(19) In another embodiment, the static mixer element 30 comprises one mixer element in the form of crossed webs disposed at an angle with a tube axis, the webs being disposed in at least two groups, the webs of any one group of elements extending substantially parallel to one another and the webs of one group crossing the webs of the other group, in which the maximum web width (b) is from 0.1 to 0.167 times the tube diameter (d), the normal between-webs distance (m) in each group is from 0.2 to 0.4 times the tube diameter (d) and the length (l) of the mixer element is from 0.75 to 1.5 times the tube diameter (d).

(20) Generally multiple static mixing elements 30 will be located in series in the housing 10. The necessary number of mixing elements 30 for a specific application will depend on the required homogeneity and contact between the fluid 2 and the fluid-contacting surface 20 comprising a biocide 22. One skilled in the art will understand that factors such as increased germ content of the fluid 2, more extensive required germ reduction, or reduced biocide 22 content in the fluid contacting surface 20 may require a larger number of static mixing elements 30 to be used. The static mixer element 30 in other embodiments may also be in the form of a random or structured packing element. Suitable random packings include Pall rings, Nutter rings, and other structures typically manufactured from thin metal sheets and typically used in mass transfer applications. Suitable structured packings include those under the tradenames Sulzer Mellapak or MellapakPlus structured packing, and such structured packings are typically manufactured from corrugated metal sheets or wire mesh or gauze and typically used in mass transfer applications.

(21) FIG. 2 shows one embodiment of apparatus 1 comprising a housing 10, an inlet 12, an outlet 14, and static mixing elements 30 contained within a series of parallel tubes, analogous in construction to a multitube heat exchanger. FIGS. 3 and 4 show specific embodiments in which the static mixer elements 30 are in the form of helical static mixing elements (FIG. 3) or in the form of cross webs (FIG. 4).

(22) FIG. 5 shows another embodiment of apparatus 1 comprising a housing 10, an inlet 12, an outlet 14, and static mixing elements 30, analogous in construction to a column filled with packing elements. In the specific embodiment shown in FIG. 5, the packing elements are structured packing elements. In other embodiments, the packing elements may be random packing elements.

(23) Suitable construction materials for the apparatus 1 and its components such as the static mixing element 30 may include plastics, preferably thermoplastics such as PE, PP, PA, PU, or PVDF; or metals such as aluminium, steel, or copper; or ceramics.

(24) The biocide 22 for use in the invention is not specifically limited. In the present application a biocide is defined as a chemical substance which can deter, render harmless, or exert a controlling effect on any harmful organism. Industrial biocides are known in the art, for example, as disclosed in Industrial Biocides: Selection And Application, edited by D. R. Karsa and D. Ashworth, and published by the Royal Society of Chemistry in 2002 (ISBN 0-85404-805-7). Suitable biocides 22 include Polymeric Guanidines, Quaternary Ammonium Compounds, Phenols, Cresols, Alcohols, Aldehydes, Glutaraldehydes, Ethylene Oxide, Organic Acids, Metallic Salts/Ions, Isothiazolinones, Peroxides, Chlorine compounds, Halogens, Anionic-, Amphotheric- and Cationic-agents, Iodophors, Dibromo-derivates, Pentamidines, Propamidines and/or subgroups of the above and/or mixtures of two or more of the above and/or their subgroups. Other biocides and mixtures of two or more of them and/or containing one or more of them may be suitable as well.

(25) In some selected embodiments the biocide 22 is in the form of a biocide-containing polymer such as a Surface Active Material (SAM) including polymeric guanidines. FIG. 6 shows the general formula of suitable polymeric guanidines in which R1 and R2=independently of each other H, [C(NH)NHR3], or an aliphatic, cycloaliphatic, araliphatic or aryl organic group, or an acyl group comprising such an organic group; R3H or an aliphatic, cycloaliphatic, araliphatic or aryl organic group, or an acyl group comprising such an organic group; I=anion and n2. Suitable polymeric guanidines include those disclosed in Biocide guanidine containing polymers, Synthesis, structure and properties, by N. A. Sivov, in New Concepts In Polymer Science, VSP Publications Leiden 2006 (ISBN-13: 978-9067644471).

(26) Suitable biocide-containing copolymers for use in the invention include polyurethanes and/or polycarbamides with polymeric guanidines as a comonomer (as disclosed in EP 2338342A1 and/or EP2338923A1) and/or quaternized polyurethanes.

(27) In certain more specific selected embodiments the biocide 22 is contained in a polymer compound. Polymers suitable for making such compounds of biocides are not specifically limited. In a preferred embodiment, the polymers include Polyurethane, Polyethylene, Polypropylene, Polyamide, Polyvinylidenfluoride, Polyester, Polyether, Polytetraflourethylene, Silicone, Polyvinylchloride, and Polycarbamide. Other suitable polymers include Polyethyleneterephthalate, Polybutyleneterephthalate, Polystyrol, Polyphenylenesulfide, Polyacrylnitrile, Polyimide, Silane, Epoxide, Rubber, Acrylnitril-Butadien-Styrol, Duroplasts, Aminoplasts, Melamine, Aramide, Polyamidimide, Polyacrylonitriles, Polymethacrylnitrile, polyacrylamides, polyimides, polyphenylene, polysilanes, polysiloxanes; polybenzimidazoles; polybenzothiazoles; polyoxazoles; polysulfides; polyarylene vinylene; polyetherketone; polyetheretherketone; polysulfones, inorganic-organic hybrid polymers; fully aromatic copolyesters, poly(alkyl)acrylates, poly(alkyl)methacrylates; polyhydroxyethylmethacrylates; polyvinyl acetates, polyvinyl butyrates, polyisoprene, synthetic rubbers; modified and unmodified cellulosics, homo- and copolymers of alpha-olefins, polyvinyl alcohols, polyalkylene oxides, polyethylene oxides, polyethylene imides, poly-N-vinylpyrrolidones; fully aromatic copolyesters, poly(alkyl)acrylates, poly(alkyl)methacrylates; polyhydroxyethylmethacrylates; polyvinyl acetates, polyvinyl butyrates, polyisoprene, synthetic rubbers; modified and unmodified cellulosics, homo- and copolymers of alpha-olefins, polyvinyl alcohols, polyalkylene oxides, polyethylene oxides, polyethylene imides, poly-N-vinylpyrrolidones; and mixtures of two or more of the above. Other polymers and/or plastics and mixtures of two or more of them and/or containing one or more of them may be suitable as well.

(28) Biocides 22 suitable for compounding into polymers include those disclosed above. Suitable polymer compounds for use in the present invention include those disclosed in EP2338923A1 and EP2338342A1. Suitable polymers for compounding include the above disclosed polymers. Preferred polymer compounds include PE and/or PP and/or PA and/or PVDF and/or PU and/or polycarbamides with Polymeric Guanidines and/or Quaternary Ammonium Compounds and/or metallic salts/ions and/or Isothiazolinones and/or Aldehydes and/or phenols. More preferred polymer compounds include PE and/or PP and/or PA and/or PVDF and/or PU and/or polycarbamides with Polymeric Guanidines, and most preferred are polymer compounds are PA and/or PU with Polymeric Guanidines.

(29) In certain embodiments such as that shown schematically in FIG. 1 the static mixing element 30 contains biocide 22 only in a surface region 21 encompassing the fluid-contacting surface 20. Preparing such static mixing elements 30 may be done by a variety of conventional thermal or solution processing methods such as laminating, extruding, dip coating, spray coating, or vapor deposition. Suitable coating processes are disclosed for example in the BASF Handbook on Basics Of Coating Technology, by A. Goldschmidt and H.-J. Streitberger, published by Vincentz Network in 2003 (ISBN 3-87870-798-3).

(30) In the case of coatings, the static mixer element 30 will often comprise a primer layer underneath the surface region 21 in order to increase the strength of the bonding and permanence of the coating on the coated static mixer element 30. Suitable chemical primers for metals such as steels or aluminum for use in the invention include zinc phosphate, iron phosphate, alkyd resins, 2K Epoxy-Zinc phosphate, Silanes, and 2K Epoxy resin. Suitable coatings for use in the invention include 2K or 1K solutions such as chlorinated rubbers, rubbers, nitrocellulosics, polyesters, phenolic resins, urea and melamine resins, epoxy resins, epoxy-silanes, acrylic resins and fluoropolymers. Preferred coatings include chlorinated rubbers, epoxy resins, fluoropolymers and epoxy-silanes, and rubbers. Specific embodiments of coating agents include fluoropolymers.

(31) For the case of coatings, typical thicknesses of the surface region 21 will be from 10 to 150 m. One skilled in art will understand that thicker surface regions 21 are better if there are stresses or a required longer lifetime in the application. One skilled in the art will understand that different coating methods will typically result in different thicknesses.

(32) Auxiliaries for the apparatus 1 are conventional and well-known in the art and may include electrical supplies, coolant and heating fluid supplies and distributions, level controllers, pumps, valves, pipes and lines, reservoirs, drums, tanks, and sensors for measuring such parameters as flow, temperatures and levels. The apparatus 1 and the process of the invention may be conveniently controlled by means of a computer interface equipped with appropriate sensors.

(33) Although not shown in the schematic figures for simplicity, one skilled in the art will understand that other conventional apparatus internals may be used without limitation in the invention, such as feed devices like feed pipes and/or sumps, heat exchangers, support plates and grids, dispersers, disperser/support plates, continuous phase distributors, support and hold-down plates, baffles, deflectors, entrainment separators, and retainers/redistributors.

(34) Another aspect of the invention is a process for reducing the germ count of a fluid containing germs 2 using an apparatus 1 of the invention. Such a process is illustrated schematically in FIG. 1. The fluid containing germs 2 is fed to the apparatus 1 via the inlet 12, and then the fluid containing germs 2 is treated on a fluid-contacting surface comprising a biocide 22 in order to form a fluid having a reduced germ count 2. The fluid having a reduced germ count 2 is subsequently removing from the apparatus 1 via the outlet 14. The flows of the fluids, 2 and 2, through the apparatus 1 are schematically illustrated by the use of arrows in FIG. 1.

(35) Processes for germ reduction in fluids are well known in the art, for example, as disclosed in the earlier cited reference books, as well as in Disinfection, Sterilization, and Preservation, edited by S. S. Block, published by Lippincott Williams and Wilkins as the 5.sup.th edition in 2001 (ISBN 0-683-30740-1). Unless indicated otherwise, the various fluid feed streams and operating parameters and conditions of such conventional types of germ reduction processes may be generally used here in the germ reduction process according to the invention and making use of the apparatus 1. In addition, in specific embodiments the apparatus of the invention may be used alone or together with gem reduction apparatuses known in the art. In one embodiment, the apparatus of the invention will be used together with ultraviolet germ reduction devices such as HF-excited gas discharge lamp.

EXAMPLES

(36) The following examples are set forth to provide those of ordinary skill in the art with a detailed description of how the apparatus 1 for germ reduction of a fluid 2, processes for reducing the germ count of a fluid containing germs 2, and uses claimed herein are evaluated, and they are not intended to limit the scope of what the inventors regard as their invention.

(37) In these examples, the apparatus 1 and process of the invention were successfully used in a typical application for the reduction of germ count of a water sample containing E. coli with a germ count which greatly exceeds the germ count commonly found in the foreseen application areas for the invented apparatus, namely between about 710.sup.7 to 710.sup.8 cells per mL.

(38) In working examples Sulzer SMV DN15 static mixing elements 30 were coated with biocide-containing polymer in the form of the following polymer compounds: polyamide (PA), polyethylene (PE). fluoropolymer, or polyurethane (PU) compounded with a guanidine or a derivative thereof as a biocide 22. The coating was carried out in a dip coating process in which the static mixing elements 30 were first placed in a coating bath for 10 s. After their removal from the bath, the solvent was evaporated and the coating was hardened by treating the static mixing elements 30 for 2 hours at room temperature, followed by 2 h at 65 C., and then 8 h at room temperature, followed by 1 h at 65 C. The resulting static mixing elements 30 thus had fluid-contacting surfaces 20 comprising a biocide 22. Apparatuses 1 were then constructed using a housing 10 in the form of a silicone tube containing a total of 5 of the biocide-coated static mixing elements 30.

(39) As comparative examples, granulates having diameters of either 3 or 5 mm and comprising the same biocide-containing polymers were tested by constructing a packed bed of the biocide-containing granulates in a silicone tube housing. The packed beds were constructed so as to have similar active biocide-containing surface areas as in the apparatuses 1 of the above working examples.

(40) Comparative tests of the germ count reduction properties of the apparatuses 1 of the working examples of the invention versus the packed beds of the prior were carried out under both static and dynamic conditions. Blank control examples were also run using apparatuses constructed using static mixing elements that had not been coated with the biocide-containing polymer. The treated fluids in the working and comparative examples were analyzed for germ count using proliferation assays based on the commonly used ISO germ count methodology.

(41) FIG. 7 shows representative results for the germ count reduction in a dynamic test of an embodiment of the apparatus 1 of the invention (coated static mixing elements) versus a control apparatus (uncoated static mixing elements). After a residence time of only 5 s the reduction in germ count is on the order of at least 510.sup.5 in the case of the coated static mixing elements 30 coated with biocide-containing polymers, and no active germs could be detected. In the case of the blank control apparatus having uncoated static mixers, no reduction in the germ count could be detected.

(42) FIG. 8 shows representative results for the germ count reduction in a dynamic test of an embodiment of the apparatus 1 of the invention (coated static mixing elements) versus a control apparatus (uncoated static mixing elements). The coated static mixing elements 30 were coated with polymer compounds based on either PE or PA and containing biocide in the working examples, and 10 s residence times were used in these dynamic tests. As in the case of the earlier examples, the germ count was essentially undetectable after 10 s in the case of the working examples, whereas it was essentially unchanged in the control test using uncoated static mixing elements.

(43) In the comparative examples based on the granulate beds, not only were the pressure losses significantly higher than those in the above working examples based on embodiments of the apparatuses 1 of the invention, but also the germ reduction was generally much poorer in the case of the packed beds of granulate than in the case of the working examples having similar active biocide-containing surface areas.

(44) FIG. 9 shows the long-term testing of stability against migration of the biocide out of model static mixing elements 30 based on aluminum coated with fluoropolymer compounds of the biocide. Under static conditions in water at 37 C. over 95 days, no biocide was detectable in the surrounding water by means of spectroscopic analysis in the case of either the static mixing elements 30 coated with the fluoropolymer compound or the uncoated blank control samples.

(45) While various embodiments have been set forth for the purpose of illustration, the foregoing descriptions should not be deemed to be a limitation on the scope herein. Accordingly, various modifications, adaptations, and alternatives can occur to one skilled in the art without departing from the spirit and scope herein.