A new generation of cost saving curatives.This article describes two new peroxide peroxide (pərŏk`sīd), chemical compound containing two oxygen atoms, each of which is bonded to the other and to a radical or some element other than oxygen; e.g. crosslinking technologies called SP (scorch protection) and CST CST abbr. 1. Central Standard Time 2. convulsive shock treatment CST Central Standard Time Noun 1. (controlled speed technology) that provide very efficient scorch protection. Scorch is unwanted or premature crosslinking that can occur during mixing or extrusion operations, or even during the actual crosslinking process. Two new products, F40M-SP and F-CST have been commercialized based on the well-known Luperox F peroxide, whose chemical name is 1,3 and 1,4-di(t-butylperoxy)diisopropylbenzene. F40M-SP and F-CST can provide three times greater scorch protection, compared to the standard grade. There are many ways to take advantage of this scorch protection, for example faster compounding, faster extrusion and faster molding operations at increased temperatures with no scorch threat and less scrap. In addition, F-CST exhibits faster curing at equivalent temperatures, which constitutes an extra source of productivity increase and cost saving. In this article, we compare the performance of these new peroxide grades to the standard peroxide in two 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 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. compositions. Discussion Arkema manufactures seven different classes of organic peroxides Organic peroxides are organic compounds containing the peroxide functional group (ROOR'). If the R' is hydrogen, the compound is called an organic hydroperoxide. Peresters have general structure RC(O)OOR. and a total of approximately 50 different unique molecules. For crosslinking various elastomers and engineering rubbers, there are two important organic peroxide classes, including the dialkyl peroxides and the peroxyketals (refs. 1 and 2). Dialkyl peroxides are by far the most efficient and cost-effective organic peroxide class for a wide range of crosslinking applications. The most common dialkyl peroxides (ref. 3) are di-cumyl peroxide, 1,3 and 1,4-di(tert-butylperoxy)diisopropylbenzene and 2,5-dimethyl-2,5-di(tert-butylperoxy) hexane hexane /hex·ane/ (hek´san) a saturated hydrogen obtained by distillation from petroleum. hex·ane n. . When faster reactivity re·ac·tiv·i·ty n. 1. The property of reacting. 2. The process of reacting. reactivity, n the degree to which a being responds to a stimulus. at lower temperatures is required, peroxyketal peroxides are selected, particularly when crosslinking unsaturated unsaturated /un·sat·u·rat·ed/ (un-sach´ur-at?ed) 1. not holding all of a solute which can be held in solution by the solvent. 2. denoting compounds in which two or more atoms are united by double or triple bonds. elastomers or when coagents are used (ref. 4). The two most common peroxyketal peroxides used in cross-linking are 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane and n-butyl-4,4-di(t-butylperoxy)valerate. The chemical structures of these peroxides govern their kinetic kinetic /ki·net·ic/ (ki-net´ik) pertaining to or producing motion. ki·net·ic adj. Of, relating to, or produced by motion. kinetic pertaining to or producing motion. behavior during thermal decomposition For the biological process, see Decomposition. For chemical decomposition in general, see Chemical decomposition. Thermal decomposition is a chemical reaction whereby a chemical substance breaks up into at least two chemical substances when heated. . Other properties are also affected, such as the energy of the free radicals produced, the physical form of the peroxide (solid or liquid), its solubility solubility Degree to which a substance dissolves in a solvent to make a solution (usually expressed as grams of solute per litre of solvent). Solubility of one fluid (liquid or gas) in another may be complete (totally miscible; e.g. , volatility, flash point, storage temperature and self accelerating decomposition temperature The Self Accelerating Decomposition Temperature (abbreviated SADT) is the lowest temperature at which an organic peroxide in a typical vessel or shipping package will undergo a self-accelerating decomposition. (ref. 5), etc. Scorch time and cure time are key parameters for crosslinking applications. These parameters strongly depend on the chemical structure, and more specifically, on the time-temperature half-life profiles of the organic peroxides (figure 1). [FIGURE 1 OMITTED] It is possible to adjust both scorch time and cure time using certain additives. In particular, traditional antioxidants Antioxidants Substances that reduce the damage of the highly reactive free radicals that are the byproducts of the cells. Mentioned in: Aging, Nutritional Supplements antioxidants, n. (ref. 7) have been used as scorch retarders to increase scorch time, which is the length of time before any significant crosslinking begins. Typically, these classical antioxidants are merely free radical scavengers free radical scavenger Free radical inactivator Any compound that reacts with free radicals in a biological system, ↓ free radical-induced damage, and protects against the indirect effects of free radicals produced by ionizing radiation, etc Examples whose role is to react with the free radicals generated by the organic peroxide, and therefore prevent them from prematurely reacting with the polymer. However, to be fully efficient, the reaction between the free radical and the scorch retarder retarder, n a chemical added to a substance to slow a chemical reaction, prolong the set of the material, and provide more working time. must be faster than the reaction between the tree radical and the polymer. The resulting trapped free radicals must then be available later on for crosslinking. This goal is very difficult to achieve in EPDM based compounds. Moreover, it is worth pointing out that the free radicals trapped by these classical scorch retarders are not able to subsequently participate in the crosslinking process. The end result is a significant loss of crosslink density, as shown in figure 2, often accompanied with an increase in the time to cure. Using more peroxide to compensate for this loss in crosslinking will reduce the scorch time, creating a vicious circle A Vicious Circle (1996) is a novel by Amanda Craig which dissects and satirizes contemporary British society. In particular, it describes the world of publishing -- its aspiring young authors, busy agents and opportunist literary critics. . Thus, these inefficient classical scorch retarders merely produce an irreversible irreversible (ir´ēvur´seb  l),adj incapable of being reversed or returned to the original state. reduction in the actual peroxide concentration. The result is very similar to merely adding less peroxide, which, of course, reduces the crosslink density, increases scorch time and unfortunately increases the cure time as well. (Note: F40ED is the traditional organic peroxide 1,3 and 1,4-di(tert-butylperoxy) diisopropylbenzene peroxide at 40% assay as a polymer masterbatch in pellet pel·let n. 1. A small pill; a pilule. 2. A small rod-shaped or ovoid mass, as of compressed steroid hormones, intended for subcutaneous implantation in body tissues to provide timed release over an extended period of time. form, for easier and faster compounding. It is used in figure 2, with and without a classical antioxidant-type scorch retarder that imparts scorch time, but sacrifices crosslinking). [FIGURE 2 OMITTED] Scorch protection technology Organic peroxide compositions based on a new scorch protection technology that provides outstanding benefits when crosslinking EPDM have been developed. This technology overcomes all the aforementioned a·fore·men·tioned adj. Mentioned previously. n. The one or ones mentioned previously. aforementioned Adjective mentioned before Adj. 1. serious limitations encountered with classical antioxidant antioxidant, substance that prevents or slows the breakdown of another substance by oxygen. Synthetic and natural antioxidants are used to slow the deterioration of gasoline and rubber, and such antioxidants as vitamin C (ascorbic acid), butylated hydroxytoluene scorch retarders. As shown in figure 3, the main benefit of the new SP technology is its faster and efficient free radical trapping trapping, most broadly, the use of mechanical or deceptive devices to capture, kill, or injure animals. It may be applied to the practice of using birdlime to capture birds, lobster pots to trap lobsters, and seines to catch fish. ability, providing significantly longer scorch time protection compared to the classical retarder, with a crosslinking efficiency equivalent to the standard peroxide with additive additive In foods, any of various chemical substances added to produce desirable effects. Additives include such substances as artificial or natural colourings and flavourings; stabilizers, emulsifiers, and thickeners; preservatives and humectants (moisture-retainers); and . [FIGURE 3 OMITTED] F40M-SP is the first peroxide grade commercialized using the SP technology, based upon 1,3 and 1,4-di(t-butylperoxy)diisopropylbenzene. F40M-SP is a proprietary scorch resistant peroxide polymer masterbatch, compounded at 40% assay in EPDM. (The physical form of F40M-SP is a free-flowing EPDM polymer pellet.) F40ED is the standard 40% peroxide EPDM masterbatch, in pellet form. In this article, we provide the results obtained using two proprietary, commercial EPDM formulations representing two different applications, including seals and automotive. The comparison of F40M-SP with F40ED using an EPDM seal formulation formulation /for·mu·la·tion/ (for?mu-la´shun) the act or product of formulating. American Law Institute Formulation is shown in figure 4. The crosslink density and the time to final cure have been found to be comparable. Scorch time has been measured at two different temperatures at 145[degrees]C using a Mooney viscometer viscometer Instrument for measuring the viscosity (resistance to internal flow) of a fluid. In one type, the time taken for a given volume of fluid to flow through an opening is recorded. and at 185[degrees]C using an RPA RPA Remote Patron Authentication RPA Rural Payments Agency (UK Department of Environment, Food and Rural Affairs) RPA Replication Protein A RPA RNAse Protection Assay RPA Regional Plan Association RPA Random-Phase Approximation (ref. 8). The scorch time attained with F40M-SP at 145[degrees]C is more than two times longer than the standard peroxide F40ED. This advantage is even larger at lower compounding temperatures. We found that F40M-SP can provide a scorch time that is about three times longer than the standard peroxide at 130[degrees]C, which is a commonly used mixing or drop-temperature. More interestingly for this EPDM seal application, the scorch time difference at 185[degrees]C is about 25% longer with F40M-SR This result clearly indicates a possible reduction in scrap and even a shorter mold mold, name for certain multicellular organisms of the various classes of the kingdom Fungi, characteristically having bodies composed of a cottony mycelium. The colors of molds are caused by the spores, which are borne on the mycelium. cycle time (cure time), leading to improved productivity. Indeed, with such a scorch time improvement, one can envision an increase in mold temperature, which would result in a much shorter cycle time without scorch related problems. [FIGURE 4 OMITTED] In figure 5, we compare the standard F40ED to the new F40M-SP in a proprietary automotive EPDM compound. We found that F40M-SP offers a scorch time that is three times longer when compounding at 125[degrees]C, based upon the [t.sub.S5] Mooney scorch time values. Time to 90% of final cure ([t.sub.C90] mins.) and final crosslink densities ([M.sub.H]) are comparable when crosslinking at 190[degrees]C using an RPA. Thus, F40M-SP provides significant improvement in scorch time with virtually no change in the other important cure characteristics. [FIGURE 5 OMITTED] SP peroxides provide greater productivity The scorch protection shown in figure 5 can directly improve productivity. One may increase mixer mixer, either of two electronic devices in which two or more signals are combined. In the type of mixer used in radio receivers, radar receivers, and similar systems, a signal is translated upward or downward in frequency. speed to provide faster compounding (as more process safety is obtained). Other options include going from a time consuming two-pass mixing step to a more efficient one-pass mixing step. One-pass mixing is typically not economical with the standard peroxide due to scorch issues that necessitate ne·ces·si·tate tr.v. ne·ces·si·tat·ed, ne·ces·si·tat·ing, ne·ces·si·tates 1. To make necessary or unavoidable. 2. To require or compel. slower mixer speeds, making the process too costly. The SP peroxide provides the benefits of a taster taster /tast·er/ (tas´ter) an individual capable of tasting a particular test substance (e.g., phenylthiourea, used in genetic studies). and more economical mixing process due to greater scorch time protection at compounding temperatures. For extrusion compounding, faster screw speed (higher RPM (1) (Revolutions Per Minute) With electric and electronics devices, RPM measures the rotational speed of the motor's spindle. Floppy disks rotate at 300 RPM, while hard disks rotate from 3,000 to 15,000 RPM. ) may be possible, again due to the significantly greater scorch time protection. Faster screw speeds provide higher productivity (throughput). Normally taster screw speeds would not be possible with the standard peroxide, as that would also increase temperatures due to shear-heating, thereby increasing the risk of scorch. This scorch protection would be particularly appreciated in injection molding injection molding n. A manufacturing process for forming objects, as of plastic or metal, by heating the molding material to a fluid state and injecting it into a mold. processes, where scorch strongly penalizes production rate. Controlled speed technology This is a new and very unique grade of peroxide with enhanced benefits, based upon the previously mentioned scorch protection technology. The CST peroxide grade was designed to provide the same scorch protection as the SP grade, however, overall the peroxide formulation is much more active. As a result, the time to final cure is significantly shorter. Thus, CST provides the benefit of a significantly longer scorch time equivalent to that of the SP, with a shorter cure time to further increase productivity. The physical form of the F-CST peroxide is a free-flowing powder on inert inert /in·ert/ (in-ert´) inactive. in·ert adj. 1. Sluggish in action or motion; lethargic. 2. filler fill·er 1 n. One that fills, as: a. Something added to augment weight or size or fill space. b. A composition, especially a semisolid that hardens on drying, used to fill pores, cracks, or holes in wood, plaster, . In figure 6, the rheometer rhe·om·e·ter n. An instrument for measuring the flow of viscous liquids, such as blood. cure curves show that F-CST provides the same scorch time protection as F40M-SP with a much faster rate of cure, thus a shorter cure time. The state of cure for both F40M-SP and F-CST products is equivalent to the standard 40% assay product F40ED, on an equal weight basis. [FIGURE 6 OMITTED] Seeking the ideal peroxide formulation The elastomer crosslinking industry has been seeking an ideal peroxide formulation with the benefits of slower reactivity at compounding temperatures, while simultaneously possessing faster reactivity at cure temperatures. These are the precise benefits of the F-CST peroxide grade. F-CST exhibits the same enhanced scorch time protection as the SP peroxide grade F40M-SR while simultaneously providing a 20% faster cure rate at equivalent crosslinking temperatures. Thus, F-CST provides the benefits of increased compounding safety with the ability to further improve productivity by providing faster cure rates without increasing crosslinking temperatures. As shown in figure 7, F-CST has a longer scorch time (about three times more than F40ED at a standard compounding temperature) and a shorter cure time (more than a 20% faster cure rate compared to F40ED and F40M-SP). Another way to express the gain in scorch time is to consider an increase in compounding temperature without reducing scorch time when compared to the standard peroxide grade with no retarder. This increase in compounding temperature might result from a faster mixing speed to reduce mix time or perhaps a problematic, highly mineral-filled compound. In figure 8, F40M-SP and F-CST provide equivalent scorch time profiles that are clearly superior in performance compared to the standard peroxide F40ED. Figure 8 shows that the [t.sub.S5] Mooney scorch times of F40M-SP and F-CST at 142[degrees]C are equivalent to the scorch time of the standard peroxide F40ED being compounded at a lower temperature of 130[degrees]C. This represents a 12[degrees]C difference in mixer temperature with equivalent scorch time when using SP or CST peroxides. [FIGURE 8 OMITTED] Using the SP or CST type peroxides, it is possible to use a faster mixing speed that would generate a 12[degrees]C higher mixing temperature. Specifically, we found that F40M-SP and F-CST have the same scorch time protection at 142[degrees]C versus 130[degrees]C for the standard peroxide, F40ED. Higher mixer temperatures would indicate faster mixer speeds and shorter compounding cycles, helping to reduce process cost. Hence these new peroxide grades provide the benefit of a wider processing window and the opportunity to improve productivity by providing the ability to shorten (audio, compression) Shorten - A form of lossless audio compression. mixing time by increasing mix speed compared to the standard peroxide grade. Table 1 lists the RPA crosslinking data at 190[degrees]C and Mooney scorch time data (at the lower temperatures), for F40ED, F40M-SP and F-CST. These peroxide systems were compared on an equal weight basis of 8.0 phr. The data clearly underscore The underscore character (_) is often used to make file, field and variable names more readable when blank spaces are not allowed. For example, NOVEL_1A.DOC, FIRST_NAME and Start_Routine. (character) underscore - _, ASCII 95. the benefits of the new SP and CST peroxide grades. Significantly higher Mooney [t.sub.S5] scorch time protection is achieved with F40M-SP and F-CST at the lower compounding temperatures. The lower the temperature, the greater the performance advantage compared to the standard peroxide. This is particularly important when compounding standard peroxides into highly filled or reactive reactive /re·ac·tive/ (re-ak´tiv) characterized by reaction; readily responsive to a stimulus. re·ac·tive adj. 1. Tending to be responsive or to react to a stimulus. 2. systems that are typically mixed at very controlled speeds to prevent scorch. Furthermore, F-CST provides a significantly faster rate of cure based on the [tC.sub.90] values at 190[degrees]C. Therefore, F-CST also provides the benefit of improved productivity (e.g., a 20% cure time) with no change in process temperature. We also studied the performance of F-CST compared to the standard peroxide F40ED blended with various crosslinking coagents. In figure 9, we compare the various mechanical properties obtained with F-CST to F40ED blended with three of the most commonly used coagents, including TAC 1. TAC - Translator Assembler-Compiler. For Philco 2000. 2. TAC - Terminal Access Controller. (triallyl cyanurate), TRIM (also known as TMPTMA, trimethylolpropane trimethacrylate) and HVA-2 (N,N'-phenylene bismaleimide). The amount of coagent used in each case was adjusted to obtain comparable [M.sub.H] values. The phr values of coagent and peroxide used are provided below each bar graph in figure 9. [FIGURE 9 OMITTED] Interestingly, it was found that for the most part, F-CST provides an equivalent crosslink level ([M.sub.H] value) when compared on an equal weight basis to the blends of the standard peroxide (F40ED) and coagent. Furthermore, F-CST leads to comparable tensile strength tensile strength Ratio of the maximum load a material can support without fracture when being stretched to the original area of a cross section of the material. When stresses less than the tensile strength are removed, a material completely or partially returns to its , elongation elongation, in astronomy, the angular distance between two points in the sky as measured from a third point. The elongation of a planet is usually measured as the angular distance from the sun to the planet as measured from the earth. at break and compression set values. These data suggest an opportunity for increased cost-savings, as the use of a coagent may not be necessary when using F-CST. To complete the comparison of F-CST versus the standard peroxide F40ED blended with various coagents, we show our Mooney scorch time and RPA crosslinking data for these blends. The results are summarized in table 2. The results show that F-CST has good crosslinking efficiency compared to F40ED blended with coagents. F-CST also provides one of the fastest rates of cure, about 30% faster than a F40ED-TAC based system, and is equivalent in speed to the HVA-2 (m-N,N'-phenylenebismaleimide) coagent system. However, the bismaleimide coagent is very reactive and can create scorch problems. This is clearly seen when measuring Mooney [T.sub.S5] scorch times at 125[degrees]C and 135[degrees]C. By far, the best system for scorch time is the F-CST. When looking at these scorch time values, the reader fully realizes looking at these scorch time values, the reader fully realizes the exceptional behavior of F-CST, which provides the shortest cure process with the best (longest) scorch time protection. Conclusion Arkema has commercialized two new grades of peroxide based on a novel and efficient scorch protection technology. This technology has been applied to one of the most widely used and efficient dialkyl type peroxides to create two new commercial products: F40M-SP and F-CST. The physical form of F40M-SP is a free-flowing polymer pellet: F-CST is a free-flowing powder on inert filler. F40M-SP provides outstanding scorch protection (three times the scorch time of the standard product, F40ED) while maintaining equal weight cure performance. F-CST is a remarkable evolution of F40M-SP as it concomitantly con·com·i·tant adj. Occurring or existing concurrently; attendant. See Synonyms at contemporary. n. One that occurs or exists concurrently with another. offers a better scorch time (same as F40M-SP) and a shorter cure time (20% faster than F40M-SP or F40ED). It is also demonstrated in this article that F-CST may possibly replace some peroxide and coagent blends. The extension of SP and CST technologies to other peroxide grades is in progress.
Table 1--comparison F40ED, F40M-SP and F-CST
8 phr each: F40ED F40M-SP F-CST
[M.sub.H] (dN.m) at 190[degrees]C 24.2 23.5 24.4
[T.sub.C90] (min.:s) at 190[degrees]C 2:14 2:13 1:48
[T.sub.S5] (min.:s) at 120[degrees]C 13:56 48:53 45:29
[T.sub.S5] (min.:s) at 130[degrees]C 7:37 20:08 21:24
[T.sub.S5] (min.:s) at 140[degrees]C 4:09 8:39 8:38
Table 2--comparison of F-CST with F40ED plus typically used coagents
Peroxide type 8 phr 6 phr
F-CST F40ED
Coagent type -- 2 phr TAC
[M.sub.H] (dN.m) at 190[degrees]C 24.4 24.0
[T.sub.C90] (min.:sec.) 190[degrees]C 1:47 2:26
[T.sub.S5] (min.:sec.) 125[degrees]C 32:33 12:48
[T.sub.S5] (min.:sec.) 135[degrees]C 14:02 6:28
Tensile strength (MPa) 15.0 15.3
Elongation (%) 250 248
Compression set (%) 15.2 15.6
Peroxide type 6 phr 6 phr
F40ED F40ED
Coagent type 4 phr TRIM 1 phr HVA 2
[M.sub.H] (dN.m) at 190[degrees]C 24.5 24.5
[T.sub.C90] (min.:sec.) 190[degrees]C 2:09 1:47
[T.sub.S5] (min.:sec.) 125[degrees]C 9:24 9:34
[T.sub.S5] (min.:sec.) 135[degrees]C 4:06 4:33
Tensile strength (MPa) 14.2 14.3
Elongation (%) 239 228
Compression set (%) 14.6 14.60
Figure 4--performance comparison between F40ED and F40M-SP
(EPDM seal type compound)
F40M-SP: Equivalent [M.sub.H] and [t.sub.c90] vs. std. peroxide
F40ED F40MSP
[M.sub.H] at 185[degrees]C in dN-M 21.8 21.0
[t.sub.c90] at 185[degrees] (min.:sec.) 4:21 4:20
F40M-SP: +120% Mooney scorch 2:22 5:11
[t.sub.S5] at 145[degrees]
F40M-SP: +25% 0:32 0:43
[t.sub.S2] at 185[degrees]
Note: Table made from bar graph.
Figure 5--performance comparison between F40ED and F40M-SP
(EPDM based automotive compound)
F40M-SP: Equivalent [M.sub.H] and [t.sub.c90] vs. std. peroxide
F40ED F40MSP
[M.sub.H] at 190[degrees]C in dN-M 21.8 21.0
[t.sub.c90] at 185[degrees] (min.:sec.) 4:21 4:20
F40M-SP: >3x [t.sub.S5] Mooney scorch @ 125[degrees]C; 2.5x @
135[degrees]C
[t.sub.S5] Mooney scorch time
F40M-SP F40ED
125[degrees]C 10:33 32:18
135[degrees]C 5:41 14:00
145[degrees]C 3:10 5:30
Note: Table made from bar graph
Figure 7: performance comparison: F40Ed-F-CST
(crosslinking EPDM)
F40 F40M-SP F-CST
Comparable cure efficiency
[M.sub.H] at 190[degrees]C (dN-m) 24.2 23.5 24.4
Three times longer [t.sub.S5] Mooney scorch time @ 130[degrees]C
[t.sub.SO5] 130[degrees]C (min.:s) 07:37 20:08 21:24
Cure time is 20% faster with F-CST at the same temperature
[t.sub.C90] 190[degrees]C (min.:s) 2:14 2:13 1:48
Note: Table made from bar graph.
Figure 9--mechanical properties comparison with typically used coagents
Comparable mechanical performance
8F-CST 6 F40+ 6 F40+ 6 F40+
2 TAC 4 TRIM 1 HAV2
Tensile strength (Mpa) 15.0 15.3 14.2 14.3
Elongation at break (%) 250 248 239 228
% compression set--24 hrs. 15.2 15.6 14.6 14.6
@ 160[degrees]C
Note: Table made from bar graph.
References (1.) Luperox--Crosslinking Rubber, Elastomer, Polyethylene polyethylene (pŏl'ēĕth`əlēn), widely used plastic. It is a polymer of ethylene, CH2=CH2, having the formula (-CH2-CH2-)n , (A Windows NT/95/98/2000/ME/XP compatible PC compute To perform mathematical operations or general computer processing. For an explanation of "The 3 C's," or how the computer processes data, see computer. CD disk) from Arkema. (2.) Leonard H. Palys, Peter A. Callais, Michael F. Novits and Michael G. Moskal, Technical paper "Selection and use of organic peroxides for crosslinking," paper no. 2, presented at a meeting of the Rubber Division, American Chemical Society The American Chemical Society (ACS) is a learned society (professional association) based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has over 160,000 members at all degree-levels and in , Indianapolis, IN, (May 5-8, 1998). (3.) Product Bulletin, Dialkyl Peroxides, Arkema. (4.) Leonard H. Palys and Peter A. Callais, "Understanding organic peroxides to obtain optimal crosslinking performance," Rubber World, vol. 229, no. 3, pp. 35-41 (Dec., 2003). (5.) "Organic peroxides--their safe handling and use," (A Windows NT/95/98/2000/ME/XP compatible PC computer CD disk) from Arkema. (6.) Technical publication and computer diskette The official name for the floppy disk. See floppy disk. diskette - floppy disk , "Half-life--peroxide selection based on half-life," Arkema. (7.) Herman G. Dikland, Ph.D. Thesis from the University of Twente--Coagents in peroxide vulcanizations of EP(D)M rubber; Chapter 6, BHT BHT butylated hydroxytoluene, an antioxidant used in foods, cosmetics, pharmaceuticals, and petroleum products. BHT n. A crystalline phenolic antioxidant used to preserve fats and oils, especially in foods. as a scorch retarder in EPDM peroxide vulcanizations. (8.) MV2000E Mooney viscometer and RPA (rubber process analyzer analyzer /ana·ly·zer/ (an´ah-li?zer) 1. a Nicol prism attached to a polarizing apparatus which extinguishes the ray of light polarized by the polarizer. 2. ) from Alpha Technologies. |
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