Antimicrobial rubber solves cleaning challenges in food processing, packaging, medical and other applications. (Tech Service).The world is teeming teem 1 v. teemed, teem·ing, teems v.intr. 1. To be full of things; abound or swarm: A drop of water teems with microorganisms. 2. with microscopic organisms such as bacteria, fungi and yeasts. Some of these microorganisms are highly beneficial to humans, while others cause stains and odors and can actually damage products and property. Unfortunately, rubber compounds are particularly vulnerable to microbial microbial pertaining to or emanating from a microbe. microbial digestion the breakdown of organic material, especially feedstuffs, by microbial organisms. attack due to their chemical constituents (ref. 1). Use of plasticizers plasticizers mostly triaryl phosphates, such as tricresyl, triphenyl phosphates, which are poisonous. See also triorthocresyl phosphate. , lubricants, processing oils and the rubber base itself provide an ideal source of hydrocarbon nutrients that support microbial growth (ref. 2). Further, rubber parts are frequently used in warm, moist environments rich in microorganisms that provide ideal conditions for the proliferation of these life forms. This, in turn, can lead to cleaning challenges requiring significant equipment downtime and disassembly dis·as·sem·ble v. dis·as·sem·bled, dis·as·sem·bling, dis·as·sem·bles v.tr. To take apart: disassemble a toaster. v.intr. 1. , and premature deterioration of molded rubber parts. To reduce or inhibit microorganisms both within and on the surface of rubber materials (ref. 3), compounders have tried blending antimicrobial additives into elastomers with varied success. Because these organic chemicals have a tendency to leach out of the matrix material, not all areas of a part are protected (ref. 4), and the microbe-suppressing properties tend to diminish over time as the additive migrates away. Furthermore, there are growing concerns about the relative safety of many of these biocides. As a response to this problem, a new line of antimicrobial heat-cured rubber (HCR HCR High Commissioner for Refugees (UN) HCR Home Condition Report HCR Health Care Reform HCR Highway Contract Route (US Postal Service) HCR High Consistency Rubber HCR Human Cognitive Reliability ) compounds--available in a variety of product forms for most processing options--has been developed. These compounds have demonstrated excellent control of microbial growth both within and on the surface of the treated material (ref. 5). A new and patented biocide biocide (bī`əsīd'), synonym for pesticide. used in these compounds does not leach away, so parts achieve much more thorough and long-term protection. While highly effective as an antimicrobial, the technology requires no special handling and has regulatory registrations around the world. As an added benefit, the technology can be used in almost any thermoset A polymer-based liquid or powder that becomes solid when heated, placed under pressure, treated with a chemical or via radiation. The curing process creates a chemical bond that, unlike a thermoplastic, prevents the material from being remelted. See thermoplastic. elastomer elastomer (ĭlăs`təmər), substance having to some extent the elastic properties of natural rubber. The term is sometimes used technically to distinguish synthetic rubbers and rubberlike plastics from natural rubber. family. This article will discuss the new line of antimicrobial rubber and its benefits, as compared with untreated rubber or rubber treated with conventional organic biocides. Applications challenged by microbial activity By virtue of their function and end-use environment, certain products and applications are more prone to damage and deterioration by microbial growth. Food and beverage F&B is a common abbreviation in the United States and Commonwealth countries, including Hong Kong. F&B is typically the widely accepted abbreviation for "Food and Beverage," which is the sector/industry that specializes in the conceptualization, the making of, and delivery of foods. handling/ processing equipment--whether a cutting board in a restaurant, an appliance in the kitchen, or conveyor belting and rollers in a factory--are prime candidates. The same can be said about many medical device and drug production systems. Products used in wet or damp environments are also at risk. These include anti-fatigue/anti-slip mats in restaurants, caulk caulk also calk v. caulked also calked, caulk·ing also calk·ing, caulks also calks v.tr. 1. and weather-stripping for windows and baths, and gaskets and seals in filtration systems. Components located in hard-to-service areas of equipment provide similar challenges. Users must often disassemble dis·as·sem·ble v. dis·as·sem·bled, dis·as·sem·bling, dis·as·sem·bles v.tr. To take apart: disassemble a toaster. v.intr. 1. machinery to clean these parts, or replace them entirely as a result of microbial growth. Potential uses for elastomeric products with antimicrobial properties include coatings, seals, gaskets, o-rings, wheels, casters, diaphragms, bladders, packings, liners, tubing and belts for applications such as: * Medical and pharmaceutical equipment; * food and beverage processing equipment; * dairy handling/processing equipment; * largo and small appliances; * storage tanks and containers; * filtration and fluid handling equipment; * sporting goods Noun 1. sporting goods - sports equipment sold as a commodity commodity, trade good, good - articles of commerce sports equipment - equipment needed to participate in a particular sport , clothing and footwear; * sanitary fittings for shower/sauna/bath; * conveyor belts and rollers; * anti-fatigue matting; * packaging machinery; * building materials/roofing membranes; * pool/pond liners; and * HVAC (Heating Ventilation Air Conditioning) In the home or small office with a handful of computers, HVAC is more for human comfort than the machines. In large datacenters, a humidity-free room with a steady, cool temperature is essential for the trouble-free ducting duct·ing n. 1. A duct or system of ducts. 2. Material for making ducts. in automobiles, etc. Traditional antimicrobial agents and their problems Today, demand for antimicrobial (AM) products is growing rapidly, with more than $1 billion spent annually on biocides for items as diverse as liquid soap, health and beauty aids, undergarments, food-processing conveyor belts, medical wound-care devices, catheters and rubber mats. In the battle to control microbes that can cause deterioration of rubber and other parts, the best approach is to create multiple hurdles to discourage microbial growth. Hence, in applications most prone to microbial buildup, not only are chemical disinfectants used regularly to keep surfaces clean, but also antimicrobial agents are embedded within the rubber matrix to help inhibit growth in the first place. Integral antimicrobial agents For an extra measure of antimicrobial performance, manufacturers have incorporated organic biocides within many common products to help inhibit growth of microorganisms. Originally developed for use as preservatives preservatives, n.pl food additives that hinder spoilage by reducing the growth of microorganisms. Include nitrates and nitrites, benzoates and sulfites, and many others. in liquid systems such as latex paint, deodorants, shampoos, liquid soaps and other surface disinfectants, etc., some of these chemicals have subsequently been adapted for use in solid materials such as rubber. A number of chemical families has been used to provide antimicrobial properties in rubber compounds, including: * Quaternary quaternary /qua·ter·nary/ (kwah´ter-nar?e) 1. fourth in order. 2. containing four elements or groups. qua·ter·nar·y adj. 1. Consisting of four; in fours. amine amine (əmēn`, ăm`ēn): see under amino group. amine Any of a class of nitrogen-containing organic compounds derived, either in principle or in practice, from ammonia (NH3). compounds; * organo-arsenic compounds; * organo-zinc compounds; and * organo-tin compounds. However, the use of integral organic biocides has been accompanied by a variety of shortcomings A shortcoming is a character flaw. Shortcomings may also be:
Leaching of antimicrobial agents A major challenge with organic biocides is that they tend to bloom to the surface and subsequently leach out of the material in which they are incorporated (ref. 6), directly affecting the overall long-term antimicrobial performance of the end-use product. Longevity of antimicrobial properties The tendency of organic biocides to migrate out of the rubber matrix can lead to significant decreases in antimicrobial performance in a treated article or product over time. Sometimes a part containing an organic-based antimicrobial agent can lose its performance after only a few cleaning cycles of uses. Because they are migratory, organic biocides provide minimal duration of product protection and antimicrobial performance. Organoleptic or·gan·o·lep·tic adj. 1. Relating to perception by a sensory organ. 2. Involving the use of sense organs. organoleptic effects Migration of these chemicals also may cause organoleptic (i.e., taste/smell) effects in polymer systems, causing a molded product to impart a disagreeable taste and/or smell. Toxicity issues during use While they are often highly effective in controlling of suppressing microbial growth, many organic biocides raise concerns of toxicity to humans and the environment. As a result, some of these chemicals have been deemed unsafe for use in medical and food-contact applications due to their inherent toxicity and the increased risk of exposure when the biocide leaches from the treated article (ref. 7). For example, a number of environmental and health organizations are now calling for legislation to limit the use of organic biocides, encouraging consumers not to purchase certain products containing triclosan (ref. 8), while other organizations have mandated a global bah on tributyl tin tributyl tin one of the constituents in defouling paint used on the exterior of boats. (TBT TBT, n See theta brainwave training. TBT Transcervical balloon tuboplasty, see there ) in marine paints by 2008 (ref. 8). Toxicity issues during manufacturing The majority of these organic biocides decompose de·com·pose v. de·com·posed, de·com·pos·ing, de·com·pos·es v.tr. 1. To separate into components or basic elements. 2. To cause to rot. v.intr. 1. at elastomeric processing temperatures exceeding 250[degrees]C (ref. 10). In the case of triclosan and its chlorinated chlorinated /chlo·ri·nat·ed/ (klor´i-nat?ed) treated or charged with chlorine. chlorinated charged with chlorine. chlorinated acids some, e.g. derivatives, heating can cause the chemicals to volatilize vol·a·til·ize intr. & tr.v. vol·a·til·ized, vol·a·til·iz·ing, vol·a·til·iz·es 1. To become or make volatile. 2. To evaporate or cause to evaporate. and corrode cor·rode v. cor·rod·ed, cor·rod·ing, cor·rodes v.tr. 1. To destroy a metal or alloy gradually, especially by oxidation or chemical action: acid corroding metal. rubber molding equipment. In certain situations, they may break down into dioxins (or dioxin-like molecules), a well-known class of highly toxic highly toxic Occupational medicine adjective Referring to a chemical that 1. Has a median lethal dose–LD50 of ≤ 50 mg/kg when administered orally to 200-300 g albino rats 2. compounds (refs. 11-13). New silver-based antimicrobial rubber compounds Given the high need for antimicrobial protection on numerous rubber parts and the challenges presented by the use of organic biocides within the elastomer's matrix, scientists began evaluating inorganic, silver-based technologies. Silver was a good candidate for such uses owing to its long history of relatively safe use as a biocide. Silver as a biocide The ancient Greek historian Herodotus reported that troops under the command of the King of Persia used flagons of silver to carry boiled water for drinking (ref. 14), and later historians mentioned similar anecdotes about the armies of Alexander the Great. Silver is widely documented for use in water disinfection disinfection, n the process of destroying pathogenic organisms or rendering them inert. disinfection, full oral cavity, n a procedure used to reduce active periodontal disease, usually completed within a certain short time frame. (ref. 15) and for therapeutic uses including the use of AgN[O.sub.3] solutions for the prevention of ophthalmia neonatorum ophthalmia neonatorum: see conjunctivitis. (ref. 16) and silver sulfadiazine as a topical chemoprophylaxis chemoprophylaxis /che·mo·pro·phy·lax·is/ (-pro?fi-lak´sis) prevention of disease by means of a chemotherapeutic agent. che·mo·pro·phy·lax·is n. Disease prevention by use of chemicals or drugs. agent for burns. Unlike antibiotics and certain organic biocides, the mechanism of action of silver against microbes is very non-specific, making it extremely difficult and rare for microbial populations to develop resistance. Silver is considered sale and as having low toxicity to humans. In fact, it has been used for millennia for eating utensils, cups, jewelry and other decorative and functional devices associated with food preparation and serving and bodily adornment. While silver technologies had previously been evaluated as a biocide in rubber compounds, success had been hampered by the irreversible binding of silver ions to the sulfur-curing agents and accelerators traditionally used in these polymers, rendering the silver ineffective as a biocide. Furthermore, the presence of silver in a rubber compound could oxidize oxidize /ox·i·dize/ (ok´si-diz) to cause to combine with oxygen or to remove hydrogen. ox·i·dize v. 1. To combine with oxygen; change into an oxide. 2. , causing discoloration dis·col·or·a·tion n. 1. a. The act of discoloring. b. The condition of being discolored. 2. A discolored spot, smudge, or area; a stain. Noun 1. in light-colored rubber parts. Subsequent research by Milliken chemists has led to the invention of non-sulfur-cure rubber formulations containing an effective and durable silver-based antimicrobial technology. Permanent antimicrobial rubber compounds A new family of antimicrobial heat-cured rubber compounds called Elastoguard (ref. 17) has been developed using a patented (ref. 18) silver sodium-zirconium-phosphate (NZP NZP National Zoological Park NZP Sodium Zirconium Phosphate ) ion-exchange-resin delivery system (ref. 19). These elastomers provide an effective way to control, if not halt, the viability of bacteria, fungi and yeasts in contact with rubber products. Both long-term and incremental antimicrobial activities have been demonstrated in molded parts produced from the antimicrobial compounds, even after repeated surface abrasion and washing. The biocide used is non-leaching, odorless o·dor·less adj. Having no odor. o  dor·less·ly adv.o , extremely heat stable (>800[degrees]C), extremely insoluble, and neither flammable, explosive nor corrosive. It does not affect the color stability of the molded part, so it can be used in white or light-colored compounds. Of particular interest, this technology provides both antifungal (ref. 20) as well as antibacterial antibacterial /an·ti·bac·te·ri·al/ (-bak-ter´e-al) destroying or suppressing growth or reproduction of bacteria; also, an agent that does this. an·ti·bac·te·ri·al adj. properties to finished parts--a versatility that is rarely found among traditional antibacterial compounds. Mechanism of antimicrobial action The biocide permeates the entire rubber part and slowly releases silver ions ([Ag.sup.+]) from an inorganic, NZP matrix via an ion-exchange mechanism. Uptake of silver ions by a microbe microbe /mi·crobe/ (mi´krob) a microorganism, especially a pathogenic one such as a bacterium, protozoan, or fungus.micro´bialmicro´bic mi·crobe n. can occur by several mechanisms, including active transport by systems that normally bring essential ions into the cell, as well as binding of silver ions within the bacterial envelope. Once inside the cell, silver ions begin to interrupt critical functions of the microorganism microorganism /mi·cro·or·gan·ism/ (-or´gah-nizm) a microscopic organism; those of medical interest include bacteria, fungi, and protozoa. , probably binding to thiol thiol: see mercaptan. groups found in important proteins called enzymes (ref. 21). Many of the enzymes that [Ag.sup.+] denatures are necessary in the cellular generation of energy. If the microorganism's ability to generate energy is disrupted sufficiently, the cell quickly loses its ability to grow and reproduce. Figures 1 and 2 show actual samples of silver-ion treated and untreated rubber exposed to various microorganisms. [FIGURES 1-2 OMITTED] Efficacy of antimicrobial rubber part improves with wear or washing Unlike conventional organic biocides that can quickly teach out of a part, release of [Ag.sup.+] from the surface of the antimicrobial rubber is slow, thereby maintaining an effective concentration at the surface of the elastomeric material. Interestingly, with this technology, washing or abrading the surface of the treated part can substantially increase efficacy at the product's surface. It is believed this occurs by removing very thin layers of rubber from the article's surface, thereby exposing "fresh" silver-containing NZP crystallites. How the silver-treated compounds avoid problems realized with earlier technology The new family of antimicrobial rubber compounds formulated with the silver-based biocide avoids the problems associated with untreated rubber and integral organic biocides. First, by creating an additional hurdle to microbial growth, an integral antimicrobial agent provides better protection from microbe-caused deterioration than surface disinfections alone. Unlike integral organic biocides that migrate, the silver-based biocide stays fixed, so the entire rubber matrix offers antimicrobial protection from skin to core. Furthermore, there are no longer zones of inhibition and non-inhibition. Studies performed on multiple exposures of the same sample indicate very good durability, which is enhanced over time by usage and other actions that occasionally scuff up the surface of the part, exposing more of the silver-based antimicrobial agent. Furthermore, the silver-based biocide is not sensitive to heat or shear, so it can be used in elastomers formulated for a variety of processes without concern. It is inert to all but the most aggressive chemicals. The new technology also does not impart an additional taste or smell to rubber parts and does not affect color stability. Unlike conventional biocides, there are no special handling precautions required for molding treated rubber gum or resin, aside from what would normally be used for handling such materials. Once vulcanized vul·ca·nize tr.v. vul·ca·nized, vul·ca·niz·ing, vul·ca·niz·es To improve the strength, resiliency, and freedom from stickiness and odor of (rubber, for example) by combining with sulfur or other additives in the presence of heat , the silver-based antimicrobial is encapsulated in the rubber matrix, and is non-irritating, non-toxic, non-corrosive and non-flammable. Regulatory registrations to date The antimicrobial AlphaSan employed in the new rubber compounds has been registered by a number of regulatory agencies worldwide for contact with food and potable potable /pot·a·ble/ (po´tah-b'l) fit to drink. po·ta·ble adj. Fit to drink; drinkable. potable fit to drink. water, and is used in approved medical devices. Appropriate rubber technologies and applications The new silver-based antimicrobial agent can be incorporated into virtually any heat-cured rubber for any molding process. It is currently available in a variety of rubber formulations with a hardness level ranging from 40 to 90 durometer A. The only formulation challenge encountered to date has been avoiding sulfur-based curing agents and accelerators. As previously noted, the presence of sulfur-based additives within a rubber mix will react with silver ions, rendering them ineffective as a biocide. This challenge has been overcome by switching to peroxide curing agents. Table 1 lists various rubber chemistries in which the antimicrobial agent is currently available and suggests some application areas where such compounds might be useful. Other chemistries can be formulated upon customer request. Other benefits In heat-cured rubber formulations, a switch from sulfur to peroxide-cure technology not only ensures efficacy of the silver-based biocide, but also provides additional benefits including: * Low compression set; * good heat aging; * better color characteristics; * lower odor; * no reversion; and * increased resistance to hydrogen sulfide hydrogen sulfide, chemical compound, H2S, a colorless, extremely poisonous gas that has a very disagreeable odor, much like that of rotten eggs. It is slightly soluble in water and is soluble in carbon disulfide. . Summary A new silver-based antimicrobial technology--available for the first time in a wide variety of thermoset elastomer technologies--provides added durability to molded rubber parts in applications especially prone to microbial attack. Unlike previous organic biocides embedded in the rubber matrix, this new technology does not migrate, so the treated elastomers avoid numerous problems associated with earlier technology. Furthermore, the silver biocide is extremely heat stable at elastomer processing temperatures, inert to all but the most aggressive chemicals, and requires no special handling or other precautions. High-temperature, high-pressure, and/or high-shear processes do not affect the efficacy of the treated elastomer. Elastoguard antimicrobial heat-cured rubber compounds are now commercially available from Milliken Chemical in standard formulations ranging from natural rubber, through workhorse EPDM EPDM Ethylene-Propylene-Diene-Monomer EPDM Enterprise Product Data Management EPDM Ethylene Propylene Dimonomer (industrial/commercial piping/plumbing components) EPDM Engineering Product Data Management and NBR NBR Number NBR Nightly Business Report (PBS show) NBR National Business Review (New Zealand weekly business newspaper) NBR National Bureau of Asian Research NBR National Board of Review grades, to high-performance fluoroelastomers. Within these product families, the compounds are offered in a variety of product forms, including slabs, strips, calendared sheet, granulated/pelletized and preformed into specific shapes. Within each presentation offering, the compounds can further be produced in various thicknesses and sizes for customer convenience. The compounds can also be formulated for molding (compression, transfer, injection), continuous extrusion (LCM (Liquid Crystal Monitor) A flat panel display that uses the liquid crystal (LCD) technology. See flat panel display. and UHF (Ultra High Frequency) The range of electromagnetic frequencies from 300 MHz to 3 GHz. In the U.S., analog television has used UHF channels 52 to 69 in the 700 MHz band. [where allowable]), autoclave autoclave Vessel, usually of steel, able to withstand high temperatures and pressures. The chemical industry uses various types of autoclaves in manufacturing dyes and in other chemical reactions requiring high pressures. and hot air, or for coatings.
Table 1--material type and grade designation for new antimicrobial
rubber formulations, as well as potential applications in which such
formulations might be useful by extending the life of the rubber
product
Seals and
Material type E-grade gaskets (SAG)
Packaging
Appliances machinery
Polyacrylic ACM - E [check]
rubber AEM - E
Polychloroprene CR - E [check] [check]
Epichlorohydrin ECO - E [check]
Ethylene propylene EPDM - E [check] [check]
diene modified
Fluoroelastomers FKM - E [check]
Hydrogenated nitrile HNBR - E [check] [check]
Isobutylene isoprene IIR - E [check] [check]
rubber (butyl)
Acrylonitrile butadiene NBR - E [check] [check]
rubber (nitrile)
Natural rubber NR - E [check] [check]
Polybutadiene PB - E [check] [check]
PVC nitrile PVC/NBR - E [check] [check]
Styrene butadiene SBR - E [check] [check]
rubber
Seals and Medical
Material type gaskets (SAG) accessories
Dairy
processing Construction Chatheters
Polyacrylic [check] [check] [check]
rubber
Polychloroprene [check] [check] [check]
Epichlorohydrin [check] [check] [check]
Ethylene propylene [check] [check]
diene modified
Fluoroelastomers [check] [check] [check]
Hydrogenated nitrile [check] [check] [check]
Isobutylene isoprene [check]
rubber (butyl)
Acrylonitrile butadiene [check] [check] [check]
rubber (nitrile)
Natural rubber [check]
Polybutadiene [check] [check]
PVC nitrile [check] [check] [check]
Styrene butadiene [check] [check]
rubber
Medical Food
Material type accessories processing
Shoe soles Wheels Conveyor belts
Polyacrylic [check]
rubber
Polychloroprene [check] [check]
Epichlorohydrin [check]
Ethylene propylene [check]
diene modified
Fluoroelastomers
Hydrogenated nitrile [check]
Isobutylene isoprene
rubber (butyl)
Acrylonitrile butadiene [check] [check] [check]
rubber (nitrile)
Natural rubber [check] [check] [check]
Polybutadiene [check] [check] [check]
PVC nitrile [check] [check]
Styrene butadiene [check] [check] [check]
rubber
Food Floor
Material type processing systems
Interlocking
SAG Handles Clean room tiles
Polyacrylic [check]
rubber
Polychloroprene [check] [check] [check] [check]
Epichlorohydrin [check]
Ethylene propylene [check] [check] [check] [check]
diene modified
Fluoroelastomers [check]
Hydrogenated nitrile [check]
Isobutylene isoprene [check]
rubber (butyl)
Acrylonitrile butadiene [check] [check] [check] [check]
rubber (nitrile)
Natural rubber [check] [check] [check] [check]
Polybutadiene [check] [check] [check] [check]
PVC nitrile [check] [check] [check]
Styrene butadiene [check] [check] [check] [check]
rubber
Floor
Material type systems Mats
Medical
Roll floors applications Kitchens
Polyacrylic
rubber
Polychloroprene [check] [check] [check]
Epichlorohydrin
Ethylene propylene [check] [check] [check]
diene modified
Fluoroelastomers
Hydrogenated nitrile
Isobutylene isoprene
rubber (butyl)
Acrylonitrile butadiene [check] [check] [check]
rubber (nitrile)
Natural rubber [check] [check] [check]
Polybutadiene [check] [check] [check]
PVC nitrile [check] [check] [check]
Styrene butadiene [check] [check] [check]
rubber
Material type Mats Military
Food
processing Industrial
Polyacrylic
rubber
Polychloroprene [check] [check] [check]
Epichlorohydrin
Ethylene propylene [check] [check] [check]
diene modified
Fluoroelastomers
Hydrogenated nitrile
Isobutylene isoprene
rubber (butyl)
Acrylonitrile butadiene [check] [check] [check]
rubber (nitrile)
Natural rubber [check] [check] [check]
Polybutadiene [check] [check] [check]
PVC nitrile [check] [check] [check]
Styrene butadiene [check] [check] [check]
rubber
Material type Hand rails Kitchen & bath Toys
Polyacrylic [check] [check] [check]
rubber
Polychloroprene [check] [check] [check]
Epichlorohydrin [check] [check] [check]
Ethylene propylene [check] [check] [check]
diene modified
Fluoroelastomers [check] [check] [check]
Hydrogenated nitrile [check] [check] [check]
Isobutylene isoprene [check] [check] [check]
rubber (butyl)
Acrylonitrile butadiene [check] [check] [check]
rubber (nitrile)
Natural rubber [check] [check] [check]
Polybutadiene [check] [check] [check]
PVC nitrile [check] [check] [check]
Styrene butadiene [check] [check] [check]
rubber
References (1.) Morton, M.; Rubber Technology 3rd Ed.; Van Nostrand Reinhold: New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of , 1987. (2.) Bessems, E., The Protection of Flexible Plastics Against Fungal Attack, Collaborative Study Performed by Plastic Protection Group (PPG PPG Points Per Game (basketball player statistic) PPG Power Play Goals (hockey) PPG Planning Policy Guidance (UK) PPG Programmable Pulse Generator PPG Power Puff Girls ) of the International Biodeterioration Research Group (IBRG). (3.) Pritchard, G., Plastics Additives and Compounding, 2000, 2, 18-29. (4.) Pritchard, G., Plastics Additives and Compounding, 2000, 2, 18-29. (5.) Haas, G., B. Patel and B.C. Kerr, "Elastomers exhibiting safe and durable antimicrobial properties;" ACS (Asynchronous Communications Server) See network access server. Rubber Division, Cleveland, 2001, Paper #28. (6.) Sawan, S.P. and Manivannan, G., Antimicrobial/Anti-infective Materials; Technomic Publishing Co.: Lancaster, 2000, 130-146. (7.) Zhou, Jing jing (jing) [Chinese] one of the basic substances that according to traditional Chinese medicine pervade the body, usually translated as "essence"; the body reserves or constitutional makeup, replenished by food and rest, that supports ; Bu, Ping; and Zhang Guimin, Study on dangerous chemicals of the polychlorinated dibenzo dioxin dioxin Aromatic compound, any of a group of contaminants produced in making herbicides (e.g., Agent Orange), disinfectants, and other agents. Their basic chemical structure consists of two benzene rings connected by a pair of oxygen atoms; when substituents on the rings are and polychlorinated dibenzofuran to environment, Ciba Fine Chemical Co. Ltd., Beijing, PRC. Riyong Huaxue Gongye (1997), (6), 34-36. (8.) FOE Report, February 2002. (9.) Canadian National Water Research Institute, 2002. (10.) Young, R.J. and Lovell, P.A., Introduction to Polymers 2nd Ed.; Chapman and Hall Chapman and Hall was a British publishing house, founded in the first half of the 19th century by Edward Chapman and William Hall. Upon Hall's death in 1847, Chapman's cousin Frederic Chapman became partner in the company, of which he became sole manager upon the retirement of : London, 1991. (11.) Kanetoshi, A., Ogawa, H., Katsura Katsura or Katsuura might refer to: Architecture
abbr. International Standard Serial Number :0021-9673. Netherlands Journal; Article; (Journal Article), written in English. DN 87195160 PubMed ID 3571350 AN 87195160, Medline. (12.) Menoutis, J. and Parisi, A.I., "Testing for dioxin and furan furan: see furfural. contamination in triclosan," Cosmetics & Toiletries toi·let·ry n. pl. toi·let·ries An article, such as toothpaste or a hairbrush, used in personal grooming or dressing. toiletries npl → artículos mpl de aseo (= , (2002), 117(10), 75-78. (13.) Onodera, Sukeo; Fukazawa, Manami; Tatsuno, Mari; Nakano, Hiroaki; Kitao, Takuya; and Fujimori, Kazumi, "Formations of polychlorinated dibenzo-p-dioxins and dibenzofurans during thermo-chemical reactions of polychlorinated alkylphenoxyalkylphenols," Fac. Pharmaceutical Sci., Tokyo Unir. Sci., Tokyo, Japan. Organohalogen Compounds (1997), 31, 525-528. (14.) Clement, J.L. and Jarrett, P.S., Met. Based Drugs, 1994, 1(5-6), 467-482. (15.) Sykes, G., Disinfection and Sterilization sterilization Any surgical procedure intended to end fertility permanently (see contraception). Such operations remove or interrupt the anatomical pathways through which the cells involved in fertilization travel (see reproductive system). 2nd Ed.; Spon, London, 1965. (16.) Block S.S. and Lawrence, C.A., Disinfection, Sterilization and Preservation; Lea & Febiger: London, 1968, 372-400. (17.) Trademark of Milliken Chemical. (18.) U.S. patent numbers 6,455,610 and 6,448,306, with other patents pending globally. (19.) Registered trademark of Milliken Chemical. (20.) The samples tested for antifungal performance provided 30 days of control. Furthermore, several of the samples were re-exposed to a fresh fungal inoculation inoculation, in medicine, introduction of a preparation into the tissues or fluids of the body for the purpose of preventing or curing certain diseases. The preparation is usually a weakened culture of the agent causing the disease, as in vaccination against and continued to inhibit the growth of fungi for a second round of 30 days. (21.) Feng, Q.L, et. al., J. Biomed. Mater. Res., 52, 2000, 662-668. Scott McDowell is the new business development manager for Milliken Chemical's Specialty Elastomers Business. He has also held positions in technical development and sales within the business. |
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