Compositions of isoprene and halogenated EPDM rubbers.Natural (NR) and synthetic isoprene isoprene or 2-methyl-1,3-butadiene (ī`səprēn, by  'tədī`ēn), colorless liquid organic compound. rubbers (JR) possess a complex of
well-known valuable properties but have some deficiencies, such as low
ozone and corrosion resistance, low resistance to heat aging and low
adhesion adhesion /ad·he·sion/ (ad-he´zhun)1. the property of remaining in close proximity. 2. the stable joining of parts to one another, which may occur abnormally. 3. properties. In the past few decades, numerous attempts to improve these properties of NR and IR through combination with saturated rubbers (CSPE CSPE Chlorosulfonated Polyethylene CSPE California Society of Professional Engineers CSPE Client/Server Processing Environment CSPE Communications System Planning Element CSPE Certified Software Process Engineer (QAI Global Institute) , CPE (Customer Premises Equipment) Communications equipment that resides on the customer's premises. CPE - Customer Premises Equipment , EPR EPR Electron Paramagnetic Resonance EPR Extended Producer Responsibility EPR Electronic Patient Record(s) EPR Emergency Preparedness and Response (US DHS) EPR Endpoint Reference EPR Ethylene-Propylene Rubber , etc.) and low 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. rubbers (IIR IIR - Infinite Impulse Response , halo-IIR, 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 ) have proven unsuccessful in the rubber industry. In other words Adv. 1. in other words - otherwise stated; "in other words, we are broke" put differently , until now, no perceptible per·cep·ti·ble adj. Capable of being perceived by the senses or the mind: perceptible sounds in the night. [Late Latin perceptibilis, from Latin perceptus results were obtained due to the great difference in the rate of vulcanization vulcanization (vŭl'kənəzā`shən), treatment of rubber to give it certain qualities, e.g., strength, elasticity, and resistance to solvents, and to render it impervious to moderate heat and cold. of these combined rubbers (for low unsaturated rubbers), or the impossibility Impossibility See also Unattainability. belling the cat mouse’s proposal for warning of cat’s approach; application fatal. [Gk. Lit. to find acceptable covulcanizing systems for IR and saturated rubbers. Compared to IR, even new types of highly unsaturated and quickly 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 EPDM (up to 12% of unsaturation un·sat·u·rat·ed adj. 1. Of or relating to an organic compound, especially a fatty acid, containing one or more double or triple bonds between the carbon atoms. 2. Capable of dissolving more of a solute at a given temperature. ) do not solve the problem because of an insufficient rate of vulcanization. At the same time, the third unsaturated comonomer co·mon·o·mer n. One of the compounds that constitute a copolymer. in EPDM-dycyclopentadiene-DCPD or 5-ethylydene-2-norbornene-ENB possesses up to 10 carbon atoms Noun 1. carbon atom - an atom of carbon atom - (physics and chemistry) the smallest component of an element having the chemical properties of the element , which can be the object of selective influence of halogen halogen (hăl`əjĕn) [Gr.,=salt-bearing], any of the chemically active elements found in Group 17 of the periodic table; the name applies especially to fluorine (symbol F), chlorine (Cl), bromine (Br), and iodine (I). atoms (chlorine chlorine (klōr`ēn, klôr`–) [Gr.,=green], gaseous chemical element; symbol Cl; at. no. 17; at. wt. 35.453; m.p. −100.98°C;; b.p. −34.6°C;; density 3.2 grams per liter at STP; valence −1, +1, +3, +5, +7. or bromine bromine (brō`mēn, –mĭn) [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2°C;; b.p. 58.78°C;; sp. gr. of liquid 3.12 at 20°C;; density of vapor 7. ). As we showed earlier (refs. 1-5) this could considerably alter common energy of the system and activate double bond. This can also bring to formation new active unsaturation in the third comonomer as well as, with halogen in a position, to the double bond, which stipulates a considerable rise in the rate of vulcanization of EPDM (refs. 1-5). We also showed that dehydrohalogenation of different halogen-containing structures in the third comonomer of halo-EPDM during the process of vulcanization, in the presence of dehydrohalogenated agents that are always present in rubber compositions (for example, ZnO), brings to formation new additional double bonds in situ In place. When something is "in situ," it is in its original location. , which causes additional rise in the rate of vulcanization of chlorinated chlorinated /chlo·ri·nat·ed/ (klor´i-nat?ed) treated or charged with chlorine. chlorinated charged with chlorine. chlorinated acids some, e.g. EPDM (CIEP-DM) (refs. 1-5). Experiments and results The following elastomers were used in our research: CIS-1.4-polysioprene-SKI-3 (plasticity 0.50 un, ML-100 [degrees] C-4'-38), EPDM-SKEPT-60D (1.98% DCPD DCPD Dicyclopentadiene DCPD Direct Current Potential Drop DCPD Direct Compensation Property Damage (automobile insurance coverage) DCPD Daly City Police Department (California) DCPD Directional Canister Passage Detector , ML-100 [degrees] C-4'-61), EPDM-SKEPT-60E (1.96% ENB, ML-100 [degrees] C-4'-60) and EPR-SKEP-40 (ML-100 [degrees] C-4'-44). Production of chlorinated EPDM on an industrial scale has been realized in commercial batch reactors The Batch reactor is the generic term for a type of vessel widely used in the process industries. Its name is something of a misnomer since vessels of this type are used for a variety of process operations such as solids dissolution, product mixing, chemical reactions, batch of 3,000 lifers capacity in 3% solution of [CCl.sub.4] with a simultaneous load of EPDM 130-140 kg. Rubber compositions were prepared on 160 x 320 mm rubber roll mills with 1:1.27 friction. Compositions were vulcanized at 151 [+ or -] 1 [degree] C in 2 mm press forms in electric press VP-9024M at pressure 100 [+ or -] 5 atm. Table 1 shows properties of original and chlorinated EPDM and EPR produced on commercial scale. All polymers contained, %: ash = 0.09-0.14; Fe = 0.002-0.005; volatile = 0.15-0.31.
Table 1 - properties of original and chlorinated
EPDM and EPR
Polymers
EPDM
Properties SKEPT-60D
CL, % 0.0 1.68 0.0
Iodine number, Ganus 25.6 23.4 24.2
Mooney viscosity,
100 [degrees] -4', un 64 66 65
Characteristic viscosity
dl/g 1.94 1.97 1.86
Oxygen index, % 17.1 19.1 17.4
[T.sub.10] Mooney, 120
[degrees] C, min. 41 24 32
Modules at 200%
elongation, mPa 7.6 11.0 10.3
Tensile strength, mPa 22.6 24.8 23.4
Estimated elongation, % 457 468 487
Residual elongation, % 16 12 14
Tear resistance, kN/m 51 62 59
Hardness, Shore, un 68 73 73
Rebound elasticity, % 51 50 52
t [degrees] of brittleness,
[degrees] C minus 55 55 59
Fixed marks SKEP ClSKEPT SKEP
-D -D -E
Properties
SKEPT-60E
Properties of rubber
CL, % 1.65 4.0 16.0
Iodine number, Ganus 20.8 14.0 9.6
Mooney viscosity,
100 [degrees] -4', un 66 68 67
Characteristic viscosity
dl/g 1.81 1.48 1.22
Oxygen index, % 19.2 20.8 22.4
[T.sub.10] Mooney, 120
[degrees] C, min. 19 12 8
Modules at 200%
elongation, mPa 12.4 13.4 14.9
Tensile strength, mPa 26.1 22.7 20.1
Estimated elongation, % 471 302 293
Residual elongation, % 10 11 8
Tear resistance, kN/m 67 44 41
Hardness, Shore, un 80 82 84
Rebound elasticity, % 53 49 43
t [degrees] of brittleness,
[degrees] C minus 60 50 46
Fixed marks ClSKEPT ClSKEPT ClSKEPT
-E -E4 -E16
Properties
EPR
SKEP-40
CL, % 0.0 16.0 22.1
Iodine number, Ganus 4.6 3.1 5.6
Mooney viscosity,
100 [degrees] -4', un 44 45 42
Characteristic viscosity
dl/g 1.61 1.69 1.42
Oxygen index, % 16.9 21.9 23.4
[T.sub.10] Mooney, 120
[degrees] C, min. 47(**) 43 39
Modules at 200%
elongation, mPa 9.6 15.4 18.3
Tensile strength, mPa 20.8 27.0 22.0
Estimated elongation, % 551 480 260
Residual elongation, % 14 20 3
Tear resistance, kN/m 34 62 51
Hardness, Shore, un 73 81 84
Rebound elasticity, % 50 40 35
t [degrees] of brittleness, 35
[degrees] C minus 53 40
Fixed marks SKEP ClSKEPT ClSKEP
-16 -22
(*) 100 parts of polymers contain, parts: S = 2; TMTD TMTD tetramethylthiuram disulfide. = 1.5; Captax = 0.5; Stearic acid stearic acid /ste·a·ric ac·id/ (ste-ar´ik) a saturated 18-carbon fatty acid occurring in most fats and oils, particularly of tropical plants and land animals; used pharmaceutically as a tablet and capsule lubricant and as an emulsifying = 1.0; Carbon black PM-75 = 50.0 (**) 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. cure 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. of all original and chlorinated copolymers in [CCl.sub.4] was 99.2-99.9%, t [degrees] of the beginning of evolving tracks of HCl from polymers = 175-198 [degrees] C. As is known, one of the deficiencies of synthetic IR is its low cohesive cohesive, n the capability to cohere or stick together to form a mass. strength of unvulcanized polymer, which can be compared to 25-30% of the cohesive strength of NR. Combination of IR with chlorinated EP copolymers considerably increases cohesive strength of mixtures; ClSKEPT-E more effectively increases cohesive strength in comparison with ClSKEPT-D (figure 1). [Figure 1 ILLUSTRATION OMITTED] Figure 2 shows that the strength of bonding of combined systems The Combined Systems project is a Dutch collaborative research and development project involving the key partners of the Delft Collaboration on Intelligent Systems (www.decis. (according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. H-method) to brassed wire d = 0.6 mm increases proportionately pro·por·tion·ate adj. Being in due proportion; proportional. tr.v. pro·por·tion·at·ed, pro·por·tion·at·ing, pro·por·tion·ates To make proportionate. to the content of chlorinated polymers in mixtures and the content of chlorine in polymers. [Figure 2 ILLUSTRATION OMITTED] The highest adhesion strength to brassed steel is observed in mixtures with ClSKEP-16 and ClSKEP-22. Mixtures with ClSKEPT-E possess more bonding strength to the wire than those with ClSKEPT-D containing the same chlorine content. Increase of the adhesive adhesive, substance capable of sticking to surfaces of other substances and bonding them to one another. The term adhesive cement is sometimes used in place of adhesive, especially when referring to a synthetic adhesive. strength of bonding of combined mixtures to brassed steel is an important property of such compositions. Higher properties of combined systems with ClSKEPT-E (compared to ClSKEPT-D) allow us to suggest a higher degree of their covulcanization. Our research of covulcanization of elastomers using the method of division into layers of specimens after vulcanization of two combined elastomers, i.e., by determining their ability to form a united net among macromolecules Macromolecules A large molecule composed of thousands of atoms. Mentioned in: Gene Therapy macromolecules of combined elastomers, confirmed that ClSKEPT-E has the best ability to covulcanize with SKI-3 (table 2) in comparison with ClSKEPT-D. Table 2 - the strength of bonding by division into layers of speciments SKI-3 and EP copolymers after vulcanization
Combined Character of Load of dividing
polymers destruction into layers, kN/M
Cohesive division
SKI-3 into layers 13.0
SKEP-E --"-- 7.0
ClSKEPT-E --"-- 11.5
ClSKEPT-E4 On adhesive joint 5.0
ClSKEPT-E16 --"-- 3.8
SKEPT-D --"-- 2.0
ClSKEPT-D --"-- 2.8
ClEPR-16 --"-- 4.0
ClEPR-22 --"-- 4.6
Taking into consideration the revealed difference between combined systems with SKEPT-D and SKEPT-E it was necessary to further investigate the reason of lower covulcanization of ClSKEPT-D with SKI-3. To this end we studied vulcanizing characteristics of combined systems using a Monsanto rheometer rhe·om·e·ter n. An instrument for measuring the flow of viscous liquids, such as blood. (table 3).
Table 3 - vulcanizing characteristics of combined systems
Minimum Maximum
turning turning
moment moment Time of
[M.sub.L], [M.sub.HF], beginning of
kg [multiplied kg [multiplied vulcanization
Elastomers ratio by] cm by] cm min.
SKI-3: ClSKEPT-E
100:0 4.0 36 2.2
80:20 6.0 43 2.2
60:40 8.3 42 2.5
50:50 9.0 42 2.5
40:60 10.3 41 2.5
20:80 13.0 40 2.5
1:100 15.0 42 4.0
SKI-3: ClSKEPT-D
100:0 4.0 36 2.0
80:20 5.0 31 2.0
60:40 6.6 31 2.0
50:50 8.0 29 2.2
40:60 8.7 27 2.5
20:80 10.0 21 2.5
0:100 11.0 20 8.0
Time of reaching Rate of
90% degree of vulcanization
vulcanization [V.sub.C], %
Elastomers ratio [t.sub.C(90)], min per min.
SKI-3: ClSKEPT-E
100:0 6.0 26.0
80:20 6.3 24.0
60:40 8.4 17.0
50:50 10.2 13.0
40:60 12.0 10.0
20:80 16.8 7.0
1:100 20.1 6.2
SKI-3: ClSKEPT-D
100:0 6.0 26.0
80:20 6.2 21.0
60:40 9.7 13.0
50:50 12.1 10.0
40:60 33.7 6.0
20:80 58.0 6.0
0:100 11.0 2.0
Our results show all increase in the turning moment ML, which is characteristic of hardness of raw mixtures in both systems. With the increasing portion of ClSKEPT-D the value of maximum turning moment of system MHF MHF Mental Health Foundation (London, UK) MHF Malaysian Hockey Federation MHF Method Hiding Factor MHF Medium High Frequency MHF Major Hazards Facility MHF Mixed Hydrazine Fuel MHF Magnolia House of Furniture, Inc gradually falls and remains unchanged for systems with ClSKEPT-E. Both systems demonstrate the same beginning time of vulcanization. Compared to ClSKEPT-D, it is, however, two times less for the original ClSKEPT-E. The time of reaching 90% degree of vulcanization [t'.sub.C(90)] increases proportionately to the percentage of chlorinated EPDM, although for systems with ClSKEPT-D it is higher since the vulcanization process is slower compared to systems with ClSKEPT-E. The increase of percentage of ClEPDM in systems with ClSKEPT-E results in a reduced rate of vulcanization from 26% (for SKI-3) down to 6.2% per minute. The rate of vulcanization in these systems depends on the percentage of ClEPDM and is subject to the law of additivity. These data demonstrate that the rate of vulcanization of ClSKEPT-E is 3.1 times higher than that of ClSKEPT-D and four times lower than that of SKI-3, whereas the rate of vulcanization of C1SKEPT-D is 13 times lower than that of SKI-3. To better comprehend the influence of the type of the third comonomer on the properties of ClEPDM vulcanizates and its compositions with SKI-3 we studied the structure parameters of combined systems with ClSKEPT-D and ClSKEPT-E. These parameters were determined from the data of conditional-equilibrium modules [E.sub.[infinity infinity, in mathematics, that which is not finite. A sequence of numbers, a1, a2, a3, … , is said to "approach infinity" if the numbers eventually become arbitrarily large, i.e. ]] that were obtained through testing vulcanizates of combined systems using relaxometer of axis compression. Table 4 shows the values of [E.sub.[infinity]] and molecular mass [M.sub.C] of polymers between knots of space net. Table 4 - dependence of conditional-equilibrium modules of covulcanizates and molecular mass of polymers between knots of space net on the type and proportions of ClEPDM Table 4 - dependence of conditional-equilibrium modules of covulcanizates and molecular mass of polymers between knots of space net on the type and proportions of ClEPDM
Conditional-equilibrium modules [E.sub.[infinity]]
Ratio of (mPa) and molecular mass MC
of elastomers
compositions SKEPT-D ClSKEPT-D
[E.sub. [E.sub.
SKI-3: EPDM [infinity]] [M.sub.C] [infinity]] [M.sub.C]
100:0 1.40 8,455 1.40 8,455
80:20 1.19 9,844 1.35 8,200
60:40 1.01 11,820 1.26 9,943
50:50 0.82 14,282 1.05 11,298
40:60 0.81 14,840 0.98 11,620
20:80 0.46 26,528 0.56 21,324
0:100 0.52 21,034 0.54 20,874
Ratio of
elastomers in
compositions SKEPT-E ClSKEPT-E
[E.sub. [E.sub.
SKI-3: EPDM [infinity]] [M.sub.C] [infinity]] [M.sub.C]
100:0 1.40 8,455 1.40 8,455
80:20 1.30 9,105 1.60 7,398
60:40 1.23 9,624 1.53 7,736
50:50 0.96 12,330 1.50 7,891
40:60 1.10 10,760 1.50 7,891
20:80 1.30 9,105 1.66 7,130
0:100 3.46 3,421 4.26 2,779
We can see that [E.sub.[infinity]] decreases (density of net decreases) with the increase of the portion of SKEPT-D and ClSKEPT-D, while, accordingly, density of knots of space net of covulcanizates decreases and molecular mass of polymers between knots of the net increases. For systems with SKEPT-E and ClSKEPT-E thickness of the net and density of the knots of space net is higher. For example, SKI-3: ClEPDM proportion of 60:40 (maximum ozone resistance of covulcanizates) for SKEPT-D, ClSKEPT-D, SKEPT-E and ClSKEPT-E results in the following density of knots of space net (v), respectively: 4.9 [multiplied mul·ti·ply 1 v. mul·ti·plied, mul·ti·ply·ing, mul·ti·plies v.tr. 1. To increase the amount, number, or degree of. 2. Mathematics To perform multiplication on. by] [10.sup.-5] 6.0 [multiplied by] [10.sup.-5], 5.9 [multiplied by] [10.sup.-5] and 7.4 [multiplied by] [10.sup.-5]. The analysis of all the above mentioned results showed that the rate of vulcanization of SKEPT-D is the lowest, the one for ClSKEPT-D is approximately at the level of original SKEPT-E, and the rate of vulcanization for ClSKEPT-E is the highest. This can provide explanation for much higher properties of combined systems of SKI-3 with ClSKEPT-E. These data were confirmed in our research of the structure of vulcanizing net on conditional-equilibrium modules at stretching of unfilled covulcanizates SKI-3: ClEPDM on changing coefficient coefficient /co·ef·fi·cient/ (ko?ah-fish´int) 1. an expression of the change or effect produced by variation in certain factors, or of the ratio between two different quantities. 2. [C.sub.l], in the Mooney-Rivlin equation (ref. 3). Our previous experiments showed that a careful selection of optimal vulcanizing systems is necessary for the production of covulcanizates SKI-3 with ClSKEPT-E with optimal dynamic and physico-mechanical properties. We performed a comparative study of systems, mass parts: 1. (Standard) - Altax (0.6) + DPG DPG diphosphoglycerate. (0.3) + S (1.0); 2. Altax (1.0) + DPG (0.6) + S (2.0); 3. Sulfonamide sulfonamide /sul·fon·amide/ (sul-fon´ah-mid) a compound containing the sbondSO2NH2 group. The sulfonamides, or sulfa drugs, are derivatives of sulfanilamide, competitively inhibit folic acid synthesis in microorganisms, and formerly were C (1.0) + S (2.0). Figure 3 shows that the most active system 3 produces a successful increase in dynamic durability of covulcanizates SKI-3: ClSKEPT-E up to the level of SKI-3 for all ratios of combined rubbers. [Figure 3 ILLUSTRATION OMITTED] Such an effect could not be obtained with original SKEPT-E (figure 3). 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 of combined covulcanizates with system 3 is also the highest and exceeds the values for covulcanizates with standard vulcanizing system, and moreover it is practically equal to those for original SKI-3 for all ratios of combined rubbers. It should be noted that resistance of covulcanizates to heat aging increased considerably with the increase of ClSKEPT-E percentage in covulcanizates. After the problem of reaching high physico-mechanical and dynamic properties of covulcanizates was solved, it became necessary to determine the type of chlorinated EP elastomers and the degree of their chlorination chlorination Public health Addition of chlorinated compounds to drinking water as disinfectants. Cf Ozonation. , in order to obtain covulcanizates with maximum ozone and corrosion resistance. With this aim in mind we studied ozone resistance of covulcanizates SKI-3 with different ClEPDM and ClEPR (see table 1). Figure 4 shows that ClSKEPT-E16 and ClSKEP-40 (16 and 22% C1) in all ratios with SKI-3 do not increase ozone resistance of covulcanizates. This is explainable because during the process of vulcanization these highly chlorinated polymers are subject to effective dehydrochlorination (for example, by ZnO that is always present in rubber mixes) resulting in unsaturation in the chain of polymers that is easily destroyed by ozone attack. [Figure 4 ILLUSTRATION OMITTED] It also follows from these data that the optimal EPDM for maximum improvement of ozone resistance of covulcanizates is, in this case, also ClSKEPT-E (with 1.65% C1 in the third comonomer) at ratio: SKI-3: ClSKEPT-E = 70:30. Such protective action for ClSKEPT-D (1.68% C1) is achieved only at ratio 60:40, while ClSKEPT-E (4% C1) provides such ozone resistance only at ratio SKI-3: ClSKEPT-E = 40:60. Table 5 shows comparative properties of rubber mixtures on the basis of 100% SKI-3 and ozone resistant composition SKI-3: ClSKEPT-E (70:30). Table 5 - comparative properties of mixtures based on SKI-3 and different combined systems containing ClSKEPT-E
Properties Elastomers, m.p.
SKI-3 = 70
SKI-3 = 100 ClSKEPT = 30
Plasticity, un 0.46 0.43
Mooney ML-4' at 120 [degrees]
C, un 43 46
Tensile strength, mPa 26.5 24.9
Estimated elongation, % 530 510
Residual elongation, % 15 16
Tear resistance, kN/m 93 99
Hardness, Shore A, un 52 55
t [degrees] of brittleness,
[degrees] C -61 -68
Rebound elasticity, % 47 46
Abrasion, [m.sup.3]/mDj 147 149
Dynamic durability, cycles >10(8) >10(8)
Equilibrium swell, % 251 206
Ozone resistance, h
(concentration [O.sub.3] =
5x[10.sup.-5] g/l) 12 >72
Coefficients of ozone resistance
at dynamic testing (elongation
= 20%, concentration [O.sub.3]
5x[10.sup.-5] g/l) -- --
Coefficients of heat aging at
100 [degrees] C 72 h
at tensile strength 0.41 0.71
at estimate elongation 0.28 0.46
Resistance to dynamic crack,
1,000 cycles >252 >252
Properties Mixtures for tire sidewalls
Serial SKD = 20
SKD = 50 SKI-3 = 50
SKI-3 = 50 ClSKEPT-E = 30
Plasticity, un 0.44 0.39
Mooney ML-4' at 120 [degrees]
C, un 44 48
Tensile strength, mPa 15.7 18.4
Estimated elongation, % 770 610
Residual elongation, % 14 13
Tear resistance, kN/m 89 94
Hardness, Shore A, un 56 62
t [degrees] of brittleness,
[degrees] C -60 -62
Rebound elasticity, % 41 44
Abrasion, [m.sup.3]/mDj 135 130
Dynamic durability, cycles >10(8) >10(8)
Equilibrium swell, % 258 236
Ozone resistance, h
(concentration [O.sub.3] =
5x[10.sup.-5] g/l) 39 >72
Coefficients of ozone resistance
at dynamic testing (elongation
= 20%, concentration [O.sub.3]
5x[10.sup.-5] g/l) 0.52 0.92
Coefficients of heat aging at
100 [degrees] C 72 h
at tensile strength 0.56 0.82
at estimate elongation 0.63 0.91
Resistance to dynamic crack,
1,000 cycles >252 >252
This table also shows comparative properties of a commercial serial mixture for tire sidewalls for radial radial /ra·di·al/ (ra´de-al) 1. pertaining to the radius of the arm or to the radial (lateral) aspect of the arm as opposed to the ulnar (medial) aspect; pertaining to a radius. 2. tires prepared in a commercial internal 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. with camera volume of 260 1, containing a strong protective group (Flectol Flakes - 2.0 m.p., acetonanyl - 2.0 m.p., n-nitrozodiphenylamine - 1.0 m.p.), in comparison with this composition without any protective additives, where 30 m.p. of SKD SKD Skilled SKD Semi Knocked Down SKD Samarkand, Uzbekistan (Airport Code) SKD Sigma Kappa Delta (National English Honor Society) SKD Shikimate Dehydrogenase SKD Srpsko Kulturno Drustvo (cis-1.4-polybutadiene) were substituted with 30 m.p. of ClSKEPT-E. According to these data, covulcanizates SKI-3 with ClSKEPT-E (70:30), while possessing nearly all properties of SKI-3, possess considerably improved ozone resistance (practically at the level of original EPDM) and also considerably improved resistance to heat aging. Composition for tire sidewalls with ClSKEPT-E exceeds serial mixture, especially in ozone resistance, both in static and dynamic testing dynamic testing Lab medicine A testing format in which 2+ samples of Pt blood or urine are obtained at a specified time interval. See Glucose tolerance test, Timed specimen, Xylose absorption test. as well as resistance to heat aging. The achieved data allows us to consider that the use of ClSKEPT-E in compositions based on IR (and other rubbers) as a single protective substance will be a new prospective stage in the development of recipe-building in rubber technology. This will also help to solve the problem of creating ozone- and corrosion-resistant vulcanizates of new types and considerably decrease and in some cases fully exclude the use of antiozonants and 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. in rubber compositions. Another direction in the use of ClEPDM in compositions with IR (and other rubbers) is the production of corrosion-and thermo-resistant vulcanizates. On the basis of this research we have developed a new corrosion- and thermo-resistant material BS-47. Its performance in highly aggressive media 10-200 times exceeds the performance of the best Russian and foreign analogues - rubbers and plastics. Maximum achieved continuous time of operation of BS-47 in concentrated caustic caustic, any strongly corrosive chemical substance, especially one that attacks organic matter. A caustic alkali is a metal hydroxide, especially that of an alkali metal; caustic soda is sodium hydroxide, and caustic potash is potassium hydroxide. (600-700 g/l) at 90-120 [degrees] C and pressure 2 atm reached 17 years 9 months. At the same time, serial vulcanizates or rubberized asbestos asbestos, mineral asbestos, common name for any of a variety of silicate minerals within the amphibole and serpentine groups that are fibrous in structure and more or less resistant to acid and fire. work under such conditions no longer than 6-8 months (refs. 3-5). Conclusion Chlorinated EPDM containing 1.5-2.0% C1 in 5-ethylydene-2-norbornene possesses a high rate of vulcanization, which permits to solve the problem of compatibility of isoprene rubbers with low unsaturated EPDM. Combined systems possess high cohesive strength, improved adhesion properties and dynamic and physicomechanical properties at the level of IR. The most important achievement obtained through compatibility of IR and C1EPDM is a considerable improvement of resistance of covulcanizates to heat aging and achieving the level of ozone resistance of covulcanizates comparable to the level of original EPDM. Maximum ozone resistance and optimal mechanical and dynamic properties were obtained for ratio IR (SKI-3): ClEPDM References [1.] Ronkin, G.M., "Structure and properties of halogenated halogenated pertaining to a substance to which a halogen is added. halogenated salicylanilides see rafoxanide, clioxanide. EPDM rubbers EPDM rubber (ethylene propylene diene monomer rubber) is an elastomer which is characterized by wide range of applications. EPDM rubber is used in vibrators and seals; glass-run channel; radiator, garden and appliance hose; tubing; washers; belts; and electrical insulation. ," Kautschuk and Rezina, 12, 17-23; International Polym. Sci. and Technology (1979), 6 (5), 8-13. [2.] Ronkin, G.M., "Modern situ action in production and application of chlorinated polyolefins," Inescou, 83 p.p. [3.] Ronkin, G.M. and Korneu, A.E., "The influence of type of vulcanizing group on properties of covulcanizates chlorinated EPDM with SKI-3," Kautschak and Rezina, 11, 1718. [4.] Ronkin, G.M., Mazanko, A.F. and Romashin, O. P., "Halogenated ethylene ethylene (ĕth`əlēn') or ethene (ĕth`ēn), H2C=CH2, a gaseous unsaturated hydrocarbon. It is the simplest alkene. propylene propylene /pro·pyl·ene/ (pro´pi-len) a gaseous hydrocarbon, CH3CHdbondCH2. propylene glycol a colorless viscous liquid used as a humectant and solvent in pharmaceutical preparations. diene Dienes are hydrocarbons which contain two double bonds. Dienes are intermediate between alkenes and polyenes. Classes Dienes can be divided into three classes:
[5.] Ronkin, G.M., "Properties of blends halogenated EPDM rubbers with highly unsaturated elastomers," proc. of the 6th Intern intern /in·tern/ (in´tern) a medical graduate serving in a hospital preparatory to being licensed to practice medicine. in·tern or in·terne n. . Seminar on Elastomers, Kyongju, 12-13.08. 1996; in: Elastomers, ed. by Chang-Sik Ha, Pusan National University History Pusan National University (PNU) was founded on May 1946 in Pusan, Korea's second largest metropolis, by Korean government,which has been established five months earlier than Seoul National University in Seoul. , Korean Institute of Rubber Industry, Seoul, Korea, 125-132. |
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