(P58) Latharn, J. R., Mendharn, W. E., SOC. Plast. Eng., Tech. Pap., 19, 458 (1973). (P59) Ledwoch, K. D., Kunstst.-Rundsch., 20 (1 l), 493 (1973); (12), 557 (1973). fP60) . , Lehmann. J.. Kunststoffe. 63 (7). 453 (1973). (P61) Lo, T. P.. Ching, H. F., Hsu, N. Y.. Chen. C. P., Wang. T. W., K'o Hsueh Tung Pao, 18 (33), 127 (1973); Chem. Abstr., 80, 134124 (1974). (P62) Longworth, R., Polym. Eng. Sci., 14 (2). 98 11974). (P63) Loven, A. J., O'Donneli, W. G., Sutton. G. J., Tighe. B. J., J. Polym. Sci., Polym. Chem. Ed., 11, 2031 (1973). (P64) Manin. V. N., Panshin, B. I., Bykov, V. A,, Dzhaborov. T., Fedorenko, A. G., Zavod. Lab., 39 ( l l ) , 1387 (1973); Chem. Abstr., 80, 134133 (1974). (P65) Manson, J. A,, lobst. S. A,, Acosta, R., J. Macromol. Sci., Phys., 9 (2), 301 (1974). (P66) Mark, J. E., J. Am. Chem. SOC., 94 (19), 6645 (1972). (P67) Markovitz,.H., J. Polym. Sci., Polym. Phys. Fd ., 11. -_ . ., 1769 ..11973). (P68) Martinelli. F. Hodgkin, J. H., J. Appl. Polym. Sci., 17, 1443 (1973) (P69) Massa, D. J., J. Appl. Phys., 44, 2595 11973). (P70) McCullough, R. L., Peterson, J. M., J. Appl. Phys., 44 (3). 1224 (1973). (P71) Menold, R., Burchert, B.,Angew. Makromol. Chem., 26, l(1972). (P72) Mikhailov, N. V., Zagraevskaya, I. M., Sharai, T. A,, Daniiushkin. M. N., Kolloid, Zh., 35 (5), 1009 (1973). (P73) Miltz, J., Ram, A,, Polym. Eng. Sci., 13 (4), 273 (1973). (P74) Mitsuda, Y., Schrag, J. L.. Ferry, J. D., J. Appl. Polym. Sci., 18, 193 (1974). (P75) Montaudo, G., Finocchiaro, P., Verberger, C. G., J. Polym. Sci., Polym. Chem. Ed., 11, 2727 (1973). (P76) Morgan, R. J. Nieisen, L. E., J. Macromol. Sci., Phys., 9 (2). 239 (1974). (P77) Murayarna, T., Arrnstrong, A. A,, Jr., J. Polym. Sci,, Polym. Phys. Ed., 12, 1211 (1974). (P78) Neurnann, A. W.. Moscarelio, M. A,, Epand,R . M., Biopolymers, 12 (9), 1945 (1973). (P79) Nikoiaeva, Yu. M., Gvardeeva, T. A,, Baramboirn, N. K., Win, S. N., Plast. Massy, 1973 (5), 70. (P80) Ohya, H., Imura, Y., Moriyarna. T.. Kitaoka, M., J. Appl. Polym. Sci., 18, 1855 (1974).
1.:
(P81) Osaki, K., Forlschr. Hochpolym.-Forsch.. 12, l(1973). (P82) Panchovski, D. P., Popova, M. B., Khirn. lnd. (Sofia), 45 ( l ) , 6 (1973). (P83) Phaovibul, O., Loboda-Cackovic, J.. Hosernann, R.. Balta-Calleja, F. J.. J. Polym. Sci., Polym. Phys. Ed., 11, 2273 (1973). (P84) Plajer, O., Plastverarbeiter, 24 (5), 293 (1973). (P85) Prest, W. M.. Jr., Porter, R. S..Polym. J., 4 (2). 154 (1973). (P86) Raeckas, V., Barkauskas, R.. Valiuliene, B., Liukaitis, I., Solominas, S.,Polim. Mater. lkh. Issled., Mater. Respub. Nauch.-Tekh. Konf., 12th, 1971, 279. (P87) Rawson, F. F., Rider, J. G., Polymer, 15, 107 (1974). (P88) Roberts, G. E., White, E. F. T., Phys. Glassy Polyrn., 1973, 153, Haward, R. N., Ed., Wiley, New York, N.Y. (P89) Robertson. R. E., Paul, D. R.. J. Appl. Polym. Sci., 17, 2579 (1973). (P90) Saeda, S.. J. Polym. Sci., Polym. Phys. Ed., 11 (E),1465 (1973). (P91) Salloum. R. J., Eckert. R . E., J. Appl. Polym. Sci., 17, 509 (1973). (P92) Sarbolouki, M. N., J. Appl. Polym. Sci., 17, 2407 (1973). (P93) Sasabe, H., Saito, S..Polym. J., 3 (6), 749 (1972). IP94) Sauer, J. A,, Richardson, G. C. Morrow, D. R., J. Macromol. Sci., Rev. Macromol. Chem., 9 (2), 149 (1973). (P95) Schenkel, G., Kunststoffe, 63 ( l ) , 49 (1973). (P96) Schoiz, D., Kunststoffe, 62 (12), 815 (1972). (P97) Schwarcz, A,, J. Polym. Sci., Polym. Phys. Ed.. 12. 1195 11974). (P98) Schwakz, A,; Far/nato, R . S., J. Polym. Sci., Polym. Phys. Ed., I O , 2025 (1972). (P99) Sebiile, E., Chim. Macromol., 2, 65 (1972). (P100) Sedlacek, B., Sb. Prednasek, "MAKROTEST 1973", 1, i-XVI (1973). (P101) Seyer, F. A,, Hlavacek, B., Kolloid-Z. 2. Polyrn., 251 (2), 108 (1973). (P102) Shaw, M. T., J. Appi. Polyrn. Sci., 18, 449 (1974). (P103) Sherriff, M.. Warburton, B., Polymer, 15, 253 (1974). (P104) Skwarski, T.. Laszkiewicz, 8..Mikolajczyk, T., Pryc, A,, Polimery, 18 (l), 28 (1973). (P105) Skwarski, T., Laszkiewicz, B., Mikolajczyk, T., Pryc, A,, Polimery, 18 (3), 135 (1973). (P106) Srnensky, J., Kaut. Gummi, Kunstst., 25 (12), 569 (1972). (P107) Stratton, R . A,, J. Polym. Sci., Polym. Chem.
Ed., 11, 535 (1973). (P108) Sviridenok. A. I., Belyi, V. A,, Savkin, V. G., Fiz-Khim. Mekh. Mater., 8 (6), 100 (1972). (P109) Sviridenok. A. I., Ken'ko, V. M., Belyi, V. A,, Mekh. Polim., 1973 (l), 102. (P110) Sviridenok, A. I., Savkin, V. G.. Nevzorov, V. V., Strukt. Svoistva Poverkh. Sloev Polim., 1972, 106. (P111) Tager, A. A,, Krasyuk, V. D., Dreval, V. E., Suvorova, A. I., Sidorova, L. K., Kotov, M. S.. Vysokomol. Soedin., Ser. A, 15 (E), 1747 (1973). (P112) Takeuchi, M.. Kusumoto, S.. Zairyo, 21 (229), 915 (1972). (P113) Tharnrn, F., Oesterr. Kunstst.-Z., 4 (7-8), 127 119731. (P114) Thayer, W. L., Pageau, L., Sourirajan, S.,J. Appl. Polym. Sci., 18, 1891 (1974). (P115) Toi, K., J. Polym. Sci., Polym. Phys. Ed., 11, 1829 (1973). (P116) Tsarev, P. K.. Lipatov, Yu. S.,Strukt. Svoistva Poverkh. Sloev Polim., 1972, 14, Lipatov. Yu. S.,Ed., "Naukova Durnka", Kiev, USSR. (P117) Tschamler, H., Rudorfer, D., Mitt. Chem. Forschungsinst. Wirl. Oesterr. Oesterr. Kunststoffinsf., 26 (4), 185 (1972). (P118) Turner, S..Phys. Glassy Polym., 1973, 223, Haward, R. N..Ed., Wiley, New York, N.Y. (P119) Utracki. L. A,, J. Polym. Sci., Polyrn. Phys. Ed., 12, 563 (1974). (P120) Vasil'ev, S. S.,Gvardeeva. T. A,, Zhikharev, A. P., Vysokomol. Soedin., Ser. 8, 15 (4), 248 (1973). (P121) Vavkin, A. S., Goi'dshtein, R . V., Salganik, R. L., Yushchenko, N. S., Mekh. Polim., 1973 (4), 634. (P122) Wiikes, C. E., Waiters, M. R., J. Polym. Sci., Symp. No. 43, 19 (1973). (P123) Williams, J. G., "Stress Analysis of Polymers", Halsted Press, New York, N.Y., 1973. (P124) Wintergerst, S.. Gummi, Asbest, Kunstst., 26 (12), 1034 (1973). (P125) Yamamoto, M.. Oyo Butsuri, 42 (7). 673 (1973). (P126) Zelenev, Yu. V., lnst. im. Lenina, Moscow, USSR, Vysokomol. Soedin., Ser. 8, 14 (E), 611 (1972). (P127) Zherdev. Yu. V., Metody Ispyt., Kontr. lssled. Mashinostroit. Mater., 3, 189 (1973). (P128) Ziabicki, A,, Polimery, 19 (l), 34 (1974). 1P1291 Zirnovets. V. F.. Zavod. Lab... 39 (4). . , . 480 (1973). (P130) Zsoldos, B., Bak, i., Papiripar, 16 (2), 54 (1972). I
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Rubber Coe W. Wadelin and Marion C. Morris Research Division, The Goodyear Tire and Rubber Co., Akron, OH 433 16
This review covers chemical analysis of rubber and characterization of rubber by physical, chemical, and spectrometric methods. Methods for the identification, characterization, and determination of rubber and materials in rubber are included, but the analysis of rubber additives before they are put into rubber compounds is not included. Polymers other than rubber are covered in another review in this issue ( I ) . The literature which became available to the authors between September 1972, the end of the period covered by Authors have not been supplied with free reprints for distribution. Extra copies of the review issue may be obtained from Speclal Issues Sales, ACS, 1155 16th SI., N.W., Washlngton, DC 20036. Rernlt $4 for domestlc U.S. orders: add $0.50 for additional postage for foreign destlnatlons.
the last review in the series ( 2 ) , and September 1974, is covered. Abbreviations recommended in ASTM Designation D1418-73a have been used ( 3 ) .They are listed in Table I.
GENERAL INFORMATION TLC (thin layer chromatography) has become a standard laboratory tool for identification and sometimes quantitation of curing agents and age resisters. The method is attractive because the cost of equipment is modest. The introduction of PMD (programmed multiple development) ( 4 , 5 ) of thin layer plates brings greater resolving power and greater sensitivity to TLC. When preparative scale amounts are put on plates, resolution usually suffers due to band spreading, but PMD allows retention of resolution
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Table I. Abbreviations Recommended by ASTM (3). EPDM Terpolymer of ethylene, propylene, and a diene with the residual unsaturated portion of the diene in the side chain ABR Acrylate-butadiene rubber BR Butadiene rubber CIIR Chloro-isobutene-isoprene rubber CR Chloroprene rubber IIR Isobutene-isoprene rubber IR Isoprene, synthetic, rubber NBR Nitrile-butadiene rubber NR Natural rubber SBR Styrene-butadiene rubber Silicone rubber having only methyl substituent MQ groups on the polymer chain when large amounts are chromatographed. The cost of PMD accessories, however, takes TLC out of the realm of low-priced equipment.
POLYMER IDENTIFICATION Polymers with saturated backbones were identified in vulcanized mixtures. An extracted sample was treated with ozone to break up cross-links and destroy polymers with unsaturated backbones. Infrared spectra were used to identify residual IIR or EPDM (6). Raman and infrared spectrometry were compared. Raman is more sensitive to acetylenic linkages and, in some cases, less subject to interference, e.g., 8% cis-polybutadiene was detected in high-impact polystyrene. Sample preparation is also easier for Raman as the solid sample can frequently be used in the form in which it is received. For infrared transmission measurements a solution or thin film must be prepared (7). Differential scanning calorimetry traces of individual polymers were recognizable in thermographs of cured rubber blends run in either oxygen or nitrogen atmospheres. The constituents of the blends could thereby be identified (8).
Pyrolysis a t 160 to 500 "C. followed by mass spectrometry was used to identify polymers ( 9 ) . The Weber test for polyisoprene rubbers was modified to eliminate the need for prior extraction. Control of the pyrolysis temperature a t 400 to 470 "C. is critical as butadiene polymers interfere if the temperature is over 500 "C. Fillers do not interfere (10).
MOLECULAR WEIGHTS AND DISTRIBUTIONS The most widely used method for molecular weight distributions (MWD) is still gel permeation chromatography (GPC). A review discussing GPC, ultracentrifuge, and TLC in the fractionation of polymers covers the major advantages of each (11).Information suggesting a mechanism of molecular weight fractionation in thin layer GPC was published (12). TLC in conjunction with conventional GPC led to determination of branching in polystyrene (13). GPC OPERATION General and Reviews. A review of application of GPC in the rubber industry has been written (14) covering such problems as the difficulty in obtaining meaningful MWD results on gel-containing polymers. Since even dilute solutions of some polymers plug columns, proper clarification is necessary. Metallic filters have been recommended (15).A review by Ouano presents methods of data interpretation from viscometry and light scattering and warnings concerning refractive index dependence of molecular weight 328R
and overloading effects (16). However, GPC has distinct advantages over other methods of characterization such as light scattering and osmotic pressure due to speed and reproducibility ( I 7 ) , particularly where identical procedures are used (18). Calibration of GPC. Two basic methods of calibration predominate; one relying upon the direct use of known narrow molecular weight fractions of the polymer, and the other on the use of the universal calibration curve (19). A review on molecular size concepts in GPC was written (20). Variations on means to apply the hydrodynamic volume concept to routine calibrations have been in existence for several years (21,22). Various forms of this technique exist (23). Parameters for use in conjunction with the universal calibration curve have been determined for many polymers (24, 25) and further simplification has been suggested (26). Comparisons of molecular weight values determined by use of the universal calibration curve have been made to osmotic and light scattering values with satisfactory agreement (27) and dimensional variations in other solvents considered (28). However, it has been noted that because of diffusion across the membrane, very low molecular weight fractions must be excluded from GPC calculations in order to obtain agreement with osmotic pressure molecular weights (29). A more arbitrary method using independently derived distribution functions to obtain a linear calibration also seemed successful (30). Standards. Polystyrene has most usually been used for standards for GPC because of its availability and stability. These materials are available from Pressure Chemical (31) and Waters Associates (32). Additional characterization of some materials has been accomplished by Tung, et al. (33). Poly(methy1 methacrylate) has been fractionated and used as a standard for GPC in 2,2,2,-trifluoroethanol (34). Elution volume and resolution effects are known to depend on concentration and to be smaller in poorer solvents (35, 36). Temperature effects are also known with higher efficiencies possible a t higher temperatures (37). At similar flow rates in polystyrene gels, the efficiency was found to be better with tetrahydrofuran as solvent rather than toluene (38, 39) and highly dependent on flow rate between 0.05 and 1.5 ml/min. Column Packings. Much work has continued on the properties and arrangements of columns on GPC separations. Unlike the usual belief, Ouano et al. (40), show improved resolution when columns are randomly arranged by permeability limits. Macroporous glass packings showed increased separation efficiencies with increased pore volumes. Use of tetrahydrofuran in the eluent suppressed adsorption on the packing (41). Other glass supports have been evaluated by Hg porosimetry and correlated to efficiency (42). Others studying Hg intrusion on Bioglas-500 beads related permeation parameters to pore dimensions and thus to the separation of polymer molecules by dimensions (43). Deficiencies of glass column packings for low molecular weight materials have been noted (44). Flow rates on Bioglas substrates were investigated between l and 4.5 ml/min showing serious increases in peak width a t high flow rates and distortions in the high molecular weight regions (45). Chromatographic properties of porous silica, Poracil, seem unaffected by heterogeneous pore structures. These have been evaluated by gas adsorption and Hg porosimetry (46). Treatment of silica gels with chlorosilanes improves their chromatographic properties ( 4 7 ) . Advantages in resolution can be obtained by reducing the dead volume using columns of small diameter and gel
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Coe W. Wadelln is a graduate of Mt. Union College (B.S., 1950) and Purdue University (M. S., 1951; Ph.D., 1953). Since 1953 he has been with the Research Division of the Goodyear Tire and Rubber Co. in Akron, Ohio, where he is a section head in analytical chemistry. He is a member of the American Chemical Society and its Analytical Division. He was a Fellow at MIT’s Center for Advanced Engineering Study in 1966-69.
Marlon C. Morrls, Section Head of Physical Chemistry, Basic Polymer Research Department, the Goodyear Tire and Rubber Co.. Akron, Ohio, joined the staff in 1962. Dr. Morris earned his B.S. degree at the University of Akron in 1954, his M.S. in physical chemistry in 1961, and his Ph.D. at the University of Akron Institute of Polymer Science in 1963. His interests are in the physical characterization of high polymers, particularly in methods relating inherent molecular characteristics to bulk behavior. These have included studies in rubber-like elasticity, viscoelastic re. sponse, crystallization and glass tempera-’ ture in rubber blends, and gel-permeation chromatography. He served on the committee for the Akron-Summit Polymer Conference in 1971 and 1972. Dr. Morris is a member of the American Chemical Society.
with narrow particle size distribution (48). Other procedures helpful in packing high efficiency columns, 11001200 platedfoot, have been outlined (49). Other gels for GPC work have been prepared from copoly(viny1 alcohol-vinyl chloride) and (vinyl alcohol-vinylidene chloride) (50). Others used beads of poly(acry1omorpholines) ( 5 1 ) and copolymers of 1,2-bis(4-vinyl phenyl)1,2-ethanediol and styrene (52). The influence of diluents during formation of gel was to increase the excluded molecular weight with an increase in diluent (53). Evaluation of column configurations for 8-ft lengths showed compact shapes can be used with little or no effect on resolution or retention volumes (54). Others have used coiled columns with success (55). Computer Routines. Because a great deal of time is consumed in manually calculating MWD and molecular weight averages, many laboratories have devised computer routines (17,56)which vary from accepting hand-read data to sophisticated programs using automatically collected data from multiple detectors (57).Multiple detectors such as refractive index, viscosity, IR, and UV make possible calculation of branching and copolymer composition. Programs are also available for dealing with resolution corrections and shifts in calibration (58).Equations dealing with the direct determination of instrumental spreading parameters have been proposed to avoid necessity of very narrow fraction materials (59). A good review on instrument spreading and calibration has been written (60).
GPC APPLICATIONS Compositional and Branching Heterogeneity. Development of a detector for determining viscosity on elution
has continued (61). Ideally, such a detector would simplify determination of molecular weights and allow calculation of branching. Ouano has interfaced this real time viscometer to a computer to give rapid results (57, 62). Mathematical treatment of branching and relation to viscosity is given by Shultz (63). Model systems of starlike molecules of polystyrene were used to give MWD and branching index (64).Certain anomalous behavior in viscosity has been observed with an apparent shift in the low molecular weight range (65). Polymers are often heterogeneous in more than one sense. All chains may not have the same chemical structure by monomer ratio, steric form, sequence distribution, or branching. A theoretical treatment of the analysis of polydisperse systems has been made (66). These variables are almost impossible to separate without multiple detectors, each chosen to respond in a somewhat different way so that the variables may be separated. Infrared spectrometry has been applied to carboxy-terminated polybutadienes for functionality distribution (67) and to monomer distributions in copolymers (68). Infrared detection can, of course, also be used for molecular weight determination alohe, often with excellent sensitivity and reproducibility (69). Application was made of GPC on well characterized block copolymers of styrene and isoprene with success (70). Proper use of Mark-Houwink parameters from the homopolymers can be used for the block copolymers. Results check out with osmometry (71). Quality Control. A great deal of emphasis has been placed on the use of GPC for quality control applications. These have taken several approaches, the first of which is high speed GPC. The effect of particle size, particle distributions, and column diameters have been investigated by several workers (48, 72, 73). Relationships between particle size and other parameters and resolution have been investigated resulting in Styragel being introduced by Waters Associates for high speed GPC with 10- to 15-minute analysis times being possible for some systems (74).In order to work at the high pressures involved, new injector devices have been designed which are also applicable to other forms of liquid chromatography (75). A second and novel method of GPC used for quality control purposes involves a differential method whereby the solvent is a solution of standard desired polymer product and only differences between the standard and unknown appear upon elution (76).This work appears promising but is closely related to work on vacancy permeation in GPC (77)which seems to attain equilibrium much slower and require slower flow rates. Polymerization Mechanism. MWD’s are “fingerprints” of how chains have grown and, thus, a record of kinetic factors in the polymerization process. Methods for treating mechanisms and kinetic rate constants for free radical bulk polymerizations have been examined (78). A treatment of bulk polymerization using Flory’s instantaneous distribution equation gave good results (79). Simplied expressions applicable to hand calculators have been developed (80) and are useful for determining the amount of termination by disproportionation and chain transfer. Partial differential equations on a kinetically controlled system yield expressions for concentration with elution. Characteristic features have been described (82). MWD’s with variations in reactant concentrations, initiator and soaps suggest that Smith-Ewart kinetics are adequate for a styrene emulsion polymerization system (82). Comparisons of MWD for copolymerization in batch and a continuous stirred tank reactor yielded results in agree-
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ment with theory for free radical polymerization (83, 84). Continuous reactor kinetics with branching have also been studied (85). Molecular heterogeneities M,/M, of about two are generally to be expected. Other Applications of GPC. Results of GPC on the soluble rubber after mixing with carbon black reveal narrowing of the MWD (86). A general theory of blending has been proposed to optimize blending to achieve a desired distribution (87). Reactions have been followed by GPC such as cyclization of IR (88) and shear degradation of polystyrene in solution (89). Ultrasonic degradation was limited by the original MWD (90). Shear stress and not shear rate was found to be the important factor in degradation in a high shear Couette viscometer (91). Viscoelastic behavior of IR was related to MWD (92). Correlation of Mooney viscosity to the geometric mean of the weight and number average molecular weights for SBR has proved valuable (93).
THERMAL PROPERTIES Thermal Analysis. At the Conference on Polymer Characterization by Thermal Methods which was held a t the ACS Meeting in Detroit (1973), Chiu (94) presented an overview of dynamic thermal analysis, that is, measurements based on monitoring changes in physical properties automatically with a programmed change in temperature. Most of the techniques are old in principle but new in instrumentation. Some 30 or more manufacturers market thermal analyzers (95, 96). Several reviews are cited by Chiu on various aspects of Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). Appropriate societies and journals are also referenced (94). Maurer has reviewed advances in thermogravimetric analysis of elastomer systems covering effects of oil, black, and polymer blending (97). Identification of elastomer blends can often be made using DSC through first- and secondorder transitions and the fact that degradation patterns are retained (8). Mechanical and thermal properties are often strongly affected by thermal history (98). A study of the transition temperature standards available in the range of 50-425' provides needed data for the reliable calibration of thermal analysis equipment (99). Computer simulation of DTA curves has been shown to assist in interpretation of polymerization, decomposition, and thermal reactions during analysis (100). Crystallization. Modern theories of the kinetics of crystallization, dealing largely with nucleation rates were compared to classical nucleation theory. Particular attention to transport phenomena yields a more complete understanding (101). Calorimetric measurements were made on a wide variety of polymers over a wide range of temperature. Results could be analyzed using a kinetic equation with a common expression for the transport phenomena (102). Other investigators have found the rate-determining step in macromolecules to be nucleation (103).A model describing universal relations for crystallization kinetics provides a master curve for both inorganic and organic polymers a t varying temperatures and crystallization modes (104). A treatment of reduced variables for overall crystallization rates of some rubbers was derived and successful (105). Stein developed a model for kinetics of growth of spherulites which predicts a change in the Avrami exponent as the spherulite develops. Light scattering patterns support the model (106). A theory of crystallization was formulated, treating the effects of random copolymerization in which noncrystallizable co-units are incorporated into the crystal (107).
Stress Induced Crystallization. Stress induced crystal330R
lization has long been established as a factor in the tensile strength of NR. Discrete small angle X-ray scattering due to lamellar crystals was observed and was found to be analogous to that by other crystalline polymers (108). Different morphologies were obtainable by extending samples before crystallizing and the effects on tensile strength were studied (109). The melting temperature of NR under strain was found to vary according to the Flory theory (110). Biaxially stretching NR increased the rate of crystallization. However, the equilibrium degree of crystallization decreased accompanied by melting behavior similar to that during extension (111). Crystallization of NR under high pressures produced three apparently different modes of crystallization and increased the maximum rate of crystallization (112).
Glass Transition Temperatures, Tg.A theory for linear polymers based upon the energies for various modes of molecular vibration permits the T , to be calculated from first principles for some polymers. The change in specific heat a t the T , can be calculated (113). The equations for the change in T , with stretching were derived and experiments supported an iso-configurational entropy concept (114). The Fox-Flory concept of T , as an iso-free volume state was tested. Peculiarities of chain segmental motion a t the T , in polymers with bulky aromatic substituents are discussed (115). A diffusive gas transport effect was used to estimate the size of the free volume elements in the vicinity of the T , (116). An equation of state is given for polymeric materials in which the molecules have a small amount of random flight motion about a basic fixed structure. These materials are intermediate between rubbers and glasses (117). Ultrasonic absorption has provided a means of monitoring change in modulus and can be used in determination of T , (118, 119).
Boyer has assembled in tables and graphs a variety of experimental data which permit cross-comparison between calorimetric and thermal expansion quantities related to the T , (120). Heat Capacities. The specific heat of polymers and the variations with temperature provide structural information on the nature of the transitions. An adiabatic calorimeter is preferred (121). Heat capacity values for melts of several polymers are successfully calculated on the assumption that they are the sums of two parts, one associated with molecular vibrations, the other with holes (222). A simple linear continuum model matched heat capacity data for polyhexene-1 over a range of 20-215 K (123). Thermal Conductivity. A plot of XfX, vs. TIT,, where X and X, are conductivities a t the flow and glass temperatures, yielded a curve virtually identical for all investigated polymers including NR up to the T,. Above the T,, different curves are necessary for different homologous series (124). The thermal conductivity of NR was reported between 134 to 314 K (125).
PHASE STRUCTURE Triblock Copolymers. Extensive mechanical experiments were performed on styrene-butadiene-styrene (SBS) block copolymers of differing block length. The microphase-separated domain morphology could be predicted by theory, i.e., in one case, to be cylinders of polystyrene in a continuous phase of polybutadiene. Melt processing can produce orientation and yielding effects in some directions (126). Details of morphology were examined with laser light scattering and light transmission in conjunction with DSC. Electron microscopy and mechanical properties were also used. The results verify the existence of a first order
ANALYTICAL CHEMISTRY, VOL. 47, NO. 5, APRIL 1975
phase transition of characteristic and predictable temperature (127). Studies by low angle light scattering and electron microscopy have shown SBS copolymers to exhibit liquid crystalline structures in the presence of a preferential solvent for one block. The structures, hexagonal, lamellar, and reversed hexagonal are governed by the composition of the copolymer. The effect of the weights of each block was also studied (128). Blends of polystyrene with SBS block copolymer showed compatibility as evidenced by a single phase transformation above 20 OC (129). However, a t low mixing temperatures, polystyrene acted as an inactive filler (129). Ultrasonic absorption in SBS copolymers revealed two absorption maxima attributable to the T,'s of the phases. Parallel dielectric measurements were made (119). Studies using electron and optical microscopy were reported on an elastomer with crystalline end blocks (thiacyclobutane-isoprene-thiacyclobutane) ( 130). Ionomers. A new aggregate morphological model consisting of small acid aggregates homogenously distributed throughout the amorphous phase successfully correlates the physical properties and morphology of ionomer systems (131).Wide angle X-ray was used to obtain the spacing between ionic sites. The degree of acid group aggregation increases with the acid content (131). Styrene based ionomers were studied as to the nature of the counter-ion. Neither ion size nor valency seems to greatly influence the viscoelasticity. However, the presence of unionized carboxylic groups accelerated the rate of relaxation (132).Crystallinity in certain ionomers was studied by X-ray and DSC. Annealing resulted in a secondary endotherm explained by crystallization of the hydrocarbon portion (133). Blends. The crystallization behavior, using DSC, has been used as a tool for assessing the quality of NR/IR blends. Poor blends yield a large spread in heat of fusion values when the results from many small samples are compared (134). Crystalline-amorphous blends of CR showed changes in T , and modulus with amount of crystallizable CR present (135).
POLYMER CHARACTERIZATION BY CHEMICAL AND SPECTROMETRIC METHODS Carbon-13 NMR was reviewed (136). Proton NMR a t 300 MHz is able to resolve cis-1,4, trans-1,4, and 1,2 structure in polybutadiene which cannot be done a t lower frequencies (137). Pyrolysis-mass spectroscopy a t 160-500 "C. can sometimes distinguish copolymers from homopolymer mixtures by the nature of the dimers and trimers foupd. Information about sequence distribution is also available ( 9 ) . The amounts of 4-vinylcyclohexene in pyrolysis products and succinic aldehyde in ozonolysis products were linearly related to the 1,4 content of polybutadiene (138). The differences between the peak areas produced by Curie point pyrolysis-gas chromatography of random and block copolymers were used to evaluate the sequence distribution of monomer units. Curie point pyrolysis a t 770 OC is preferred over furnace or filament pyrolysis as the latter methods give no information about the polymer microstructure (139). Butadiene-styrene copolymers containing blocks of polystyrene yield polystyrene after ozonolysis. This can be observed by infrared examination of the residue which survives ozonolysis (140). A mixture of 9:l morpholine-methyl sulfate hydrolyzes the urea bonds but leaves the urethane bonds intact in polyurethanes made from 2,4-toluenediisocyanate. Infrared measurements of the morpholinoarylureas formed and the
unreacted urethanes lead to determination of the respective groups (141).
DETERMINATION OF POLYMERS IN POLYMER MIXTURES AND CONSTITUENTS IN COPOLYMERS The use of Curie point pyrolysis was found to give improved precision in quantitative analysis of vulcanizates. Gas chromatography was used to measure the pyrolysis products. Mixtures of IR, SBR, EPDM, BR, and CIIR rubber were analyzed with standard deviation of 2% (142, 143). Data from pyrolysis-gas chromatography and infrared were combined to give results accurate to 3% on mixtures of up to three polymers (144).The method of Dinsmore and Smith was used to prepare the samples for infrared because microstructure is retained (145). The comparison of attenuated total reflection and transmission spectra of NBR showed that the ratio of absorbances of the 2237 and 1447 cm-' bands is proportional to the acrylonitrile content in both kinds of spectra (146). Astute choice of solvents enables separation of uncured rubber from various matrices, e.g., ungrafted polybutadiene from high-impact polystyrene or ABS (acrylonitrilebutadiene-styrene). The extracted rubber can be measured by NMR or infrared (147,148). NMR, infrared, refractive index, density, and iodine number were compared for determination of ethylidenenorbornene in EPDM. Refractive index was found to be most convenient. I t has precision of 0.32% (95% confidence) in the range 1 to 17%. The method is not affected by changes in ethylene content in the range 40 to 60% ethylene (149). A thermograph of BR or SBR has an exothermic peak a t 380 "C which is proportional to the butadiene content. I t is unaffected by curing (vulcanization) or carbon black loading, although cis-trans content has a small effect. The precision is 11%(95% confidence) (150).The ability to resolve TGA curves is enhanced by use of the first derivative. Blends of NR, EPDM, and SBR were successfully analyzed (97).
HALOGENS Chlorine was determined by neutron activation analysis with relative standard deviations of 4.1% a t a level of 2.9%, and 5.9% a t a level of 0.06%, respectively. The lower limit of detection was 0.01% (151). OXYGEN Oxygen was determined by activation analysis with 4 to 5% error in the range 0.4 to 6%. The oxygen content was used to find the composition of a butadiene-methacrylic acid copolymer and to follow the uptake of oxygen during heat aging (152). CURING AGENTS Sulfenamide accelerators derived from benzothiazole were identified by mass spectrometry. The rubber sample was first heated for 15 to 20 min a t 150 to 200 "C. The vapors which were formed were drawn into the mass spectrometer and scanned a t low voltage. A peak appears a t mass 135 (benzothiazole) if 2-mercaptobenzothiazole is present in the sample. Other peaks are characteristic of the amine part of the accelerator. Extender oils do not interfere (153). Another apprqach to identification of accelerators was by a combination of chemical tests. 2-Mercaptobenzothiazole and amines were identified by gas chromatography of their S-methyl and trifluoroacetamide derivatives, respectively (154).
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Hexamethylenetetramine was detected by TLC. Resotropin interferes but other methylene donors are distinguished from hexa (155). Potassium iodoplatinate was found to be useful as a visualizing agent for TLC plates. The extracts of known stocks were preferred over pure materials for establishing reference Rf values. If the presence of thiurams is suspected, isopropyl alcohol is preferred over acetone as extractant because acetone reacts with thiurams (156). Raman spectra were found to be useful for distinguishing between thiuram monosulfides, disulfides, and tetrasulfides, zinc dialkyl dithiocarbamates, and sulfur (157).
AGE RESISTERS Age resisters can be volatilized from polymers in the inlet of a mass spectrometer and then identified from their mass spectra. The temperature is low enough that no pyrolysis of the polymer takes place (9). TLC was found to be capable of separating p-phenylenediamines into three groups, viz., dialkyl, alkylaryl, and diaryl, but incapable of resolving compounds within a group (158). This is contrary to the report of Kreiner and Warner who show separations of compounds within the groups as well (159). Potassium iodoplatinate is useful as a visualizing reagent for TLC plates (156). Acetone extracts containing amine-type age resisters were spiked with measured amounts of the same age resisters labeled with carbon-14. The age resisters were then separated and their concentrations in the original samples determined by isotope dilution (160). RESIDUAL MONOMER Residual monomers were volatilized in the inlet of a mass spectrometer at temperatures low enough so that pyrolysis would not occur. The mass spectra were then used to identify them (9). Head space analysis has been used for the determination of vinyl chloride in PVC. The sample, either alone or in a solvent, is warmed in a sealed vial to concentrate the monomer in the vapor phase. A portion of the vapor is then injected into a gas chromatograph. Sensitivity is better than for methods in which solutions are injected, particularly for monomers of high volatility. The difficulties associated with large solvent peaks are minimized (161). LITERATURE CITED (1) Mitchell, J., Chiu, J., Anal. Chem., 47, 289R (1975). Wadelin. C. W., Morris, M. C., ibid., 45, 333R 119731. Am. SOC.Testing Mater., "1973 Annual Book of ASTM Standards, Pt. 28," Philadelphia, PA, 1973, p 668. Perry, J. A., Haag, K. W., Glunz, L. J., J. Chromatogr. Sci., 11, 447 (1973). Jupille, T. H., McNair, H. M., Am. Lab., 6 (9), 54 (1974). Li Gotti. I., Franzosi, M., Bonomi, G., Mater. Plast. Nastorneri, 38, 1045 (1972); Chem. Abstr., 78, 733279 (1973). Sioane, H. J., Appl. Spectrosc., 27, 217 (1973). Sircar, A. K., Lamond, T. G., Thermochim. Acta, 7, 287 (1973). Zeman, A., Angew. Makromoi. Chem., 31, 1 (1973); Chem. Abstr., 79, 42998q (1973). Bahrani. M. L., Chakravarty. N. V., Saxena, A. K., Anal. Chem., 46, 446(1974). Smith, W. V., Rubber Chem. Techno/., 45, 667 (19721. Otocka. E: P., Hellman, M. Y.. Muglia, P. M., Macromolecules, 5, 227 (1972). Beien'kii, B. G., Gankina, E. S., Nefedov, P. P., Kuznetsova, M. A.. Valchikhina, M. D.. J. Chromatogr., 77, 209 (1973).
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CARBON BLACK Identification and characterization of carbon black by microscopy were reviewed (162). Isothermal thermogravimetry at 500 "C in the presence of oxygen was applied to the residue from pyrolysis of IIR. Probability analysis of the weight loss curve was useful in analyzing mixtures of semireinforcing and fast extruding furnace blacks (97). ANALYSIS RELATED TO SAFETY AND HEALTH A study of dust from highway traffic revealed that 1.5 to 2.5% of the particulate matter can be attributed to tread rubber. The analysis was done by pyrolysis-gas chromatography (163). In further work, the traffic dust was separated by size. The particles larger than 7 micrometers contained 6.3% tread rubber while those in the size range 1 to 7 micrometers contained 4.3% tread rubber. The material smaller than 1 micrometer was not analyzed for tread rubber (164). SBR was isolated from aerosol samples by extracting the solids with benzene, then hot 0-dichlorobenzene through which a stream of oxygen was passed. The extract was concentrated on a KBr pellet and examined by infrared (165). Water extracts of rubber samples were examined by ultraviolet spectrophotometry for the presence of curing agents (166). OTHER DETERMINATIONS Calcium stearate and stearic acid were determined in IIR by infrared spectrometry. The lower limits of detection were 0.5 and 0.1% respectively (167). Silica fillers were separated from MQ by heating in nitrogen at 770 "C to volatilize the rubber. The weight of the residue for known samples was slightly greater than expected from calculations (168). Ten ppm strontium was added to tire cord dip to serve as a marker. The strontium content of the dipped cord was then measured by atomic absorption to determine the amount of dip pickup. Standard deviation ranged from 2 to 5% (169). Methods for the determination of the dry rubber content of field latex were reviewed and compared (170). Polysaccharides were identified in aqueous extracts of rubber by acid hydrolysis and thin layer chromatography (171).
(14) Evans, J. M., RAPRA Members J., 1 (7), 176 (1973). (15) Baijal, M. D., Anal. Chem., 44, 1337 (1972). (16) Ouano, A. C., J. Macromol. Sci., C9, 123 (1973). (17) Evans, J. M., Polym. Eng. Sci., 13, 401 (1973). (18) Adams, H. E., Ahad, E., Chang, M. S., Davis, D. B.. French, M., Hyer, H. J., Law, R. D., Sinkins, R. J., Stuchbury, J., J. Appl. Polym. Sci., 17, 269 (1973). (19) Grubisic. Z.,Rempp, P.. Benoit, H., J. Polym. Sci., Poiym. Lett. Ed., 5, 753 (1967). (20) Dawkins, J. V., Brlt. Polym. J., 4 (2), 87
, .- . -,. [ia79\
(21) Weiss, A. R., Cohn-Ginsberg, E., J. Polym. Sci., PartAZ, 8, 148 (1970). (22) Morris, M. C., J. Chromatogr., 55, 203 (19711. (23) Spatcrico, A. L., Coulter, B., J. Poiym. Sci., Polym. Phys. Ed., 11, 1139 (1973). (24) Evans, J. M., Polym. Eng. Sci., 13, 401 (1973). (25) Uglea. C. V., Andreescu, Rev. Roum. Chim., 17, 2021 (1972); Chem. Abstr., 76, 72781p (1973). (26) Ambler, M. R., J. Polym. Sci., Polym. Chem. Ed., 11, 191 (1973). (27) Nichols, E., Polym. Prepr., Am. Chem. Soc., Div. Polym. Chem., 12, 828 (1971).
ANALYTICAL CHEMISTRY, VOL. 47, N O . 5, APRIL 1975
(28) Nichols, E., Adv. Chem. Ser., 125, 148 (1973). (29) Ambler, M. R., Mate, R . D., J. Polym. Sci., Parf A- 7, 10,2677 (1972). (30) Swartz. T. D., J. Appl. Polym. Sci., 16, 3353 (1972). (31) Pressure Chemical Co., 3419 Smailman St., Pittsburgh, PA 15201. (32) Waters Associates, Inc., Maple St., Milford, MA 01757. (33) Tung, L. H., Runyon, J. R., J. Appl. Polym. Sci., 17, 1589 (1973). (34) Provder, T., Woodbrey, J. C., Clark, J. H., Drott, E. E., Adv. Chem. Ser., 125, 117 (1973). (35) Kato, Y., Hashimoto, T., Kobunshi Kagaku, 30 (2), 707 (1973); Chem. Abstr., 79, 32350m (1973). (36) Kato, Y., Hashimoto, T., J. Polym. Sci., Poiym. Phvs. Ed., 12. 813 119741. (37) Cooper, A. R., Bruzzone; A. k., ibid., 11, 1423 (1973). (38) Cooper, A. R., Eur. Poiym. J., 12, 1393 (1973) (39) jbiG.,-p 1381 (40) James, P. M., OUanO, A. C., J. Appl. Polym. Sci., 17, 1455 (1973). (41) Zhoanov, S. P., Belen'kii, B. G., Nefedov, P. P., Koromal'Di, E. V., J. Chromatogr., 77, 149(1973). .
(42) Cooper, A. R., Johnson, J. F., Polym. Prepr., Am. Chem. SOC., Div. Polym. Chem., 12, 738 (1971). (43) Yau, W. W., Malone, C. P.. ibid., 12, 797 (1971). (44) Cooper, A. R., J. Appi. Polym. Sci., 17, 2707 (1973). (45) Cooper, A. R., Brit. Polym. J., 5, (2). 109 (1973). (46) Cooper, A. R., Barrall, E. M., J. Appi. Poiym. Sci., 17, 1253 (1973). (47) Grigor'eva, L. A,, Ryabinina, T. I., El'tekov, Y. A.. Vysokomol. Soedin., Ser. A,. 15 ( l ) , 238 (1973); Chem. Abstr., 78, 148302f (1973). (48) Ishida, Y. K.. Kozo U., Suehiro, T., Kobunshi Kagaku, 30 ( l ) , 34 (1973). Chem. Abstr., 78, 986109 (1973). (49) Dawkins, J. V., Hemming, M., Polymer, 13, 553 (1972). Motozato, Y., Hirayama. C., Morodomi, K., Kunitake, N., Nippon Kagaku Kaishi, 1973 ( l ) , 79; Chem. Abstr., 78, 112001t(1973). Epton, R., Holloway, C., McLaren, J. V.. J. Appl. Polym. Sci., 18, 179 (1974). Braun, D., Brendlein, W., Angew. Makromol. Chem., 31, 137 (19731; Chem. Abstr., 79,
54118 (1973). Motozato, Y., Hirayama, C., Nippon Kagaku Kaishi, 1972, 1087; Chem. Abstr., 79, 5953d
(1973). Whitlock, L. R., Porter, R . S.,Johnson, J. F., J. Chromatogr. Sci., 10, 437 (1972). Heitz, W.. J. Chromafogr., 83, 223 (1973). Swanson. C. L., Ernst, J. O., Gugliemelli, L. A,, J. Appl. Poiym. Sci., 18, 1549 (1974). Ouano, A. C., Horne, D. L., Gregges. A. R., J. Poiym. Sci., Polym. Chem. Ed., 12, 307
(1974). Zahir, S. A., Greussing, A., Angew. Makromol. Chem., 24, 121 (1972): Chem. Abstr., 77, 140661f (1972). Taganov, N. G., Novikov, D. D., Korovina, G. V., Enteiis, S. G., J. Chromafogr., 72, 1
(1972). Ouano, A. C., J. Macromoi. Sci., Rev., Macromoi. Chem., 9, 23 (1973). Grubisic, G. Z., Picot, M., Gramain. P. H.. J. Appl. Polym. Sci., 16, 2931 (1972). Ouano, A. C., J. Polym. Sci., Part A-1, I O ,
2169 (1972). Schuitz, A. R., J. Poiym. Sci., Part A-2, 10,
983 (1972). Meunier. J. C., Gaiiot. Z.,Makromol. Chem., 156, 117 (1972); Chem. Abstr., 77, 75671t
(1972). Bruessau, R. J., ibid., 175, 691 (1974). Greschner, G. S., Makromoi. Chem., 168,
273 (1973). Law, R. D., J. Poiym. Sei., Poiym. Chem. Ed., 11, 175 (1973). Anderson, D. G.. Isakson, K. E., Poiym. Character., interdisciplinary Approaches, Proc. Symp., 1971, 193. Ross, J. H., Shank, R. L., Poiym. Prepr., Am. Chem. SOC., Div. Poiym. Chem., 12, 812
(1971). Ho-Duc. N.. Macromolecules, 6, 472 (1973). Franklin, S. C.. Polym. Prepr., Amer. Chem. SOC.,Div. Poiym. Chem., 12, 835 (1971). Kato, Y., Kido, S.,Hashimoto, T., J. Poiym. Sci., Polym. Phys. Ed., 11, 2329 (1973). Otocka, E. P.. J. Chromatogr., 76, 149
(1973). Limpert, R. J., Cotter, R L., Dark, W. A,, Am. Lab., 6 (9,63 (1974). Fallick. G. F., ibid., 6 (E),65 (1974). Chuang, J., Johnson, J. F., J. Appl. Poiym. Sci., 17, 2123 (1973). Otocka. E. P.. Heiiman. M. V.. J. Poivm. Sci.. ' bo/ym. Len. Ed., 12, 439 (1974). Braks, J. G., Diss. Abstr. int., 8, 34, (lo),
4935 (1974). Smith, W. B., Polym. Prepr., Am. Chem. SOC., Div. Poiym. Chem., 11, 1019 (1970) Reich, L , J. Appi. Polym. Sci., 17, 3709
(1973) Nichol, L. W., Winzor, D. J., J. Phys. Chem., 78, 460 ( 1974). Turtle, D. P., Diss. Abstr. int., 8,34 (E),3776
(1974). Hatate, Y., Nakashio, F., Kagaku Kogaku, 37 (2), 171 (1973); Chem. Abstr., 78, 136897r
(1973). Poehlein, G. W., DeGraff, A. W., Adv. Chem. Ser., 109, 75 (1972). Nagasubramanian, K.. Graessley, W. W.,
ibid, p 81. (86) Ban, L. L., Hess, W. M., Papazian, L. A., Rubber Chem. Techno/,, 47, 858 (1974). (87) Schrager, M., J. Appi. Poiym. Sci., 17, 3357 (1973). (88) Agnihotri, R . K., Falcon, D., Fredericks, E. C., J. Polym. Sci., Palf A-1. 10, 1839 (1972). (89) Breitenbach, J. W., Rigler, J. K., Wolf, B. A,, Makromoi. Chem., 184, 353 (1973); Chem. Abstr., 78, 136867f (1973). (90) Sheth, P. J., Johnson, J. F., Porter, R. S.,
(133) Marx, C. L., Cooper, S. L.. J. Macromol. Sci., 89, 19 (1974). (134) Ghijsels, A., Mieras, H. J. M. A,, J. insf. Rubber ind., 6 (6), 259 (1972). (135) Andrews, R. D.. Kawasaki, N., Polym. Prepr., Am. Chem. SOC., Div. Poiym. Chem., 13,
1200 (1972). (136) Mochei, V. D., J. Macromol. Sci., C8, 289 (1972). (137) Santee, E. R., Jr., Chang, R., Morton, M., J. Polym. Sci., Polym. Lett. Ed., 11, 449 (1973). Polym. Prepr., Am. Chem. SOC., Div. Polym. (138) Host, M.. Deur-Siftar, D., Chromatographia, Chem., 12, 513 (1971). 5, 502 (1972). (91) Abdel-Alim, A. H., Hamielec, A. E., J. Appi. (139) Alekseeva, K. V., Khramova, L. P., SolomatiPolym. Sci., 17, 3771 (1973). na, L. S.,J. Chromafogr., 77, 61 (1973). (92) Harima. H., Shibatani, K., Minatono, S.,Oy- (140) Li Gotti. I., Franzosi, M.. Bonomi. G., Mater. anagi, Y., Kobunshi Kagaku, 29, 615 (1972); Piast. Eiasfomeri, 1974, 318; Chem. Abstr., Chem. Absfr.,78, 5174e (1973). 81, 64929q (1974). (93) Kramer, O., Good, W. R., J. Appi. Poiym. Sci., (141) Kopusov, L. I., Zharkov, V. V., Plast. Massy, 16, 2677 (1972). 1973 (3). 73; Chem. Absfr., 79, 19986d (94) Chiu, J., J. Macromoi. Sci., A8 ( l ) , 3 (1974). (1973). (95) Laboratory Guide, Anal. Chem.. 44 ( l o ) , (142) Krishen. A.. Tucker, R. G., Anal. Chem., 46, (1972). 29 (1974). (96) Chem. Eng. News, 47 (34), 46 (Aug 18, (143) Krishen, A,, "Rubber and Related Products: 1969). New Methods for Testing and Analyzing," (97) Maurer, J. J., J. Macromoi. Chem., A8, 73 ASTM STP 553, Am. SOC. Testing Mater., (1974). Philadelphia, PA, 1974, p 74. (98) Dunn, C. M. R., Turner, S.,Polymer, 15, 451 (144) Davis, R., Ney, E. A,, Peake, R., Proszynski. (1974). A., J. Inst. Rubber lnd., 8, 197 (1972). (99) Wunderlich, B., Bopp, R. C., J. Thermal. (145) Dinsmore. H. L.. Smith, D. C.. Anal. Chem., Anal., 8 (3),335 (1974). 20, 1 1 (1948). (100) Taylor. L. J., Watson, S. W., Polym. Prepr.. (146) lyer, P. E., Padhye, M. R.. Silk Rayon ind. Am. Chem. SOC.,Div. Poiym. Chem., 12, 457 India, 16, 174 (1973); Chem. Abstr., 79, (1971). 1 2 6 9 7 5 ~(1973). (101) Sanchez, I. C., J. Macromol. Sci., C10, 113 (147) Turner, R. R., Carlson, D. W., Altenau, A. G., (1974). J. Elastomers Piast., 6 (2), 94 (1974). (102) Godovskii, Y. K., Slonimskii, G. L., J. Poiym. (148) Altenau, A. G., Am. Chem. SOC., Div. Anal. Sci., Poiym. Phys. Ed., 12, 1053 (1974). ' Chem., April 1974. (103) Wunderlich. B., Mehta, A,, ibid., p 255. (149) Gardner, I. J., Ver Strate. G., Rubber Chem. (104) Gandica, A,. Magill, J. H., Polymer, 13, 595 Technoi., 46, 1019 (1973). (1972). (150) Sircar, A. K., J. Appl. Poiym. Sci., 17, 2569 (105) Giuliani, G. P., Sorta, E., J. Poiym. Sci., (1973). Polym. Lett. Ed., 12, 375 (1974). (151) Butler, J. W., Marsh, R. H., Rubber Chem. (106) Stein, R. S.,J. Poiym. Sci., Polym. Phys. Ed., Technol., 45, 1560 (1972). 11, 109 (1973). (152) Fougea, D., Ghaleb. M., Gerald, P., Pineri, M., (107) Sanchez, I. C., Eby, R. K., J. Res. Nat. Bur. Rev Plast.. 49. 1063 (19721: - . Gen - . Caout. - -. .. Stand., Sect. A., 77, 353 (1973). Chem. Abstr., 78, 728269 (1973). (108) Luch, D., Yeh, G. S. Y., J. Macromoi. SCb, (153) Hilton, A. S., Altenau, A. G., Rubber Chem. 87, 121 (1973). Technoi., 46, 1035 (1973). (109) Reed, P. E., Proc. R. S.London, Ser. A,, 338 (154) Patei. S. M., Hively, R. A,, Cole, J. O., Am. (1615). 459 (1974). Chem. Soc., Div. Rubber Chem., May 1973. ( 1 10) De Candia, F., Romano, G.. Vittoria, V., J. (155) Kreiner, J. G., J. Chromatogr., 88, 423 POlym. sci., Poiym. Phys. Ed., 11, 2291 (1974). (1 973). (156) Millingen, M. B., Anal. Chem., 48, 746 (1974). (1 11) Oono, R., Miyasaka, K., ishikawa, K., ibid., p (157) Coleman, M. M., Shelton, J. R.. Koenig, J. L., 1477. Am. Chem. SOC., Div. Rubber Chem., May (1 12) Edwards, B. C., Phillips, P. C., Poiymer, 15, 1973. 491 (1974). (158) Ivan, G., Ciutacu, R., J. Chromatogr., 88, 391 (1 13) Morley, D. C. W., J. Mater. Sci., 9, 619 (1974). (1974). (159) Kreiner, J. G..Warner, W. C., ibid.. 44, 315 (114) N0se.T.. Polym. J., 4(3). 217(1973). (1969). (1 15) Lipatov. Y. S.,J. Macromoi. Sci., 87, 431 (160) Murakami, S.,Fujii, Y., Tsurugi, J.. Hamada, (1973). M.. Nakabayashi, T., Watanabe, T.,Ichihashi, (116) Ziegel, K. D., Eirich. F. R., J. Polym. Sci., H.. KobunshiKagaku, 29, 431 (1972); Chem. Poiym. Phys. Ed., 12, 1127 (1974). Abstr., 77, 127671q (1972). (1 . 17). Edwards. S. F.. Proc. R. S. London, Ser. A,. (161) Berens, A. R., Polym. Prepr., Am. Chem. 332 (1591), 439 (1973). SOC.,Div. Poiym. Chem., 15 (2), 197 (1974). (118) Papadakis, E. P., J. Appi. Phys., 45, 1218 (162) Kruse, J., Rubber Chem. Technoi., 46, 653 11 9741 (1973). (1 19) Shen, M., J. Polym. Sci., Polym. Phys. Ed., (163) Cardina, J. A., ibid., 46, 232 (1973). 11, 2261 (1973). (164) Cardina, J. A,, Am. Chem. Soc., Div. Rubber (120) Boyer, R. F., J. Macromoi. Sci., 87, 487 Chem., May 1974. (1973). (165) Brachaczek, W.. Pierson, W. R., Rubber (121) Fischer, F., Gummi, Asbest. Kunsf., 27 (6), Chem. Technol, 47, 150 (1974). 430 (1 974). (166) Zyszczynska-Florian, B., Wojewodska, S., (122) Bares, V., J. Polym. Sci., Poiym. Phys. Ed., Rocz. Panstw. Zaki. Hig., 25 ( l ) , 63 (1974); 11, 1301 (1973). Chem. Abstr., 81, 38627v (1974). (123) Bourdariat. J., Isnard, R., Odin, J., bid., p (167) Rodionova, N. M., Zhukova. V. P., Shmarlin. 1301. V. S.,Prom. Sin. Kauch., Nauch.-Tekhn. Sb., (124) Arutyunov, 6. A., Nekh. Poiim., 1972 (5), 4, 3 (1973); Chem. Absfr., 81, 26923a 912; Chem. Abstr., 78, 44391t (1973). (1974). (125) Pilsworth, M. N., Hoge, H. J.. Robinson, H. E., (168) Vondracek, P. S., Plast. Hmoty Kauc., 10, J. Mater., 7, 580 (1972). 169 (1973); Chem. Abstr., 79, 67587w (126) . , Mieras. H. J. M. A,. J. inst. Rubber ind., 7 (2). (1973). 72 (1973). (169) Firkins, J. L., Am. Chem. SOC., Div. Rubber (127) Leary, D. F., Williams. M. C., J. Poiym. Sci,. Chem., October 1973. Polym. Phys. Ed., 12, 265 (1974). (170) Anon., Rubber Res. Inst. Malaya, Planters (128) Douy. A,. Gaiiot, B.,Makromol Chem., 185, Bull., No. 124, 4 (1973). 297 (19731. (171) Piacentini, R., Novati, C., Mater. Plast. Elasto(129) Bobovich, V. V., Dinzburg, 6. N., Eremeev, V. meri, 40, 46 (1974); Chem. Abstr., 81, C., Koii. Zh., 38, 343 (1974). 145022 (1974) (130) Cheng-Yih, K., Diss. Abstr. lnf., E, 34, 4909 ( 1974). Contribution No. 532 from The Good(131) Marx, C. L., Caulfield, D. F., Cooper, S. L., year Tire & Rubber Co., Research LabMacromolecules, 6, 344 (1973). (132) Navratil, M., Eisenberg, A,, ibid., 7, 84 (1974). oratory, Akron, OH 44316. I
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