POLYVINYL ISOBUTYL ETHERS Properties and Structures C. E. SCHILDKNECHT, S. T. GROSS, H. R. DAVIDSON, J. 31. LAJ'IBERT, AND A. 0. ZOSS General Aniline and Film Corporation, Easton, P a .
Vinyl isobutyl ether is shown to give different types of high polymers depending on the conditions of polymerization. The polymer obtained by rapid polymerization with boron fluoride catalyst is substantially amorphous and rubberlike. A second type of polymer is less rubberlike, comparatively well ordered and gives an x-ray fiber diagram. A study of a variety of physical properties of
these polyvinyl isobutyl ethers and related polymers show* that the differences between the two types cannot be attributed t o degree of polymerization or chain length distribution, but result from differences i n structure betwreen the polymer chains. Several theoretical interpretations are discussed relating conditions of polymerization to spatial isoinerism in vinyl polymers.
I
often varies widely with the chain length, viscosity, or average molecular weight of the polymer. The study ot these polymere is of interest in showing the degree to which rubberlike response can exist independent of cross linkages, and to inquire why some vinyl polymers, although having a high degree of flexibility, are not rubberlike in the sense of possessing pressure-sensitive tack and reversible extensibility. Among the rubberlike polymers free of cross linkage which can be obtained by polymerization a t low temperatures with FriedelCrafts type or ionic catalysts, the polyvinyl alkyl ethers offer special interest for the study of t h e relation of structure t o physical properties, in t h a t comparatively high polymers can be prepared from a number of members of the homologous series of monomers. Of the aliphatic mono-olefinic hydrocarbons onlv the solid high polymers from ethylene and isobutylene have been studied closely. Three of the outstanding factors controlling structure and properties which can be studied in a polymer series, such as the polyvinll alkyl ethers, are the folloming: the nature of the side group (alkoxy group) ; the molecular weight, chain length, or viscosity of the polymer; and structural differences depending on the conditions of polymerization (aside from effects of chain length). The influence of any one of these factors can be clearly shown only if the other two are kept constant or variations in the other two factors are shown t o be negligible for the particular property investigated. The present paper deals primarily with the third factor which i5 a comparatively new field of high polymer study. Interest was aroused by finding t h a t several of the vinyl alkyl ethers, notably vinyl isobutyl ether, under different conditions for polymerization, can yield polymers having differences in propwties whicb cannot be attributed alone t o viscosity or molecular weight.
T HAS been reported from this laboratory (58) t h a t vinyl
isobutyl ether appeared t o give two different types of high polymers depending on the method of ionic or Friedel-Crafts polymerization employed. These rubberlike and nonrubberlike polyvinyl isobutyl ethers, h a v h g comparable degrees of polymerization, showed outstanding differences in tack, hardness, solubility, and in behavior, on milling. The variations were attributed t o structural differences between the polymer chains, which changed their shape and their ability t o form well ordered structures. This matter was investigated further because the two types of polyvinyl isobutyl ethers seemed t o represent a structural isomerism in synthetic polymers which has not been reported. The isomeric vinyl isobutyl ether polymers suggest comparison t o natural rubber and gutta-percha. I n both cases the rubberlike and nonrubberlike types cannot be transformed readily one into the other, and both are believed to involve differences in the spatial arrangement of the side groups attached t o the main chain. However, instead of representing two regular arrangements, such &s cis and trans in the natural products, t h e two polyvinyl isobutyl ethers represent a relatively disordered type (rubberlike) and a comparatively well ordered type (nonrubberlike). Only bhe latter type gave pronounced x-ray fiber patterns. I n earlier work, the rubberlike polyvinyl isobutyl ether studied was a sample of commercial Oppanol C , from abroad. I n this Laboratory a series of each type of polyvinyl isobutyl ether was prepared, including both types from the same lot of vinyl isobutyl ether monomer. Physical properties of the two types have been studied in some detail and compared with closely related polyvinyl ethers, such as polyvinyl n-butyl ether and polyvinyl lsopropyl ether. This study calls attention to the possibilities of chain isomerlam in polymers from monosubstituted or unsymmetrically substituted ethylene compounds when i t is possible t o use different techniques of polymerization. The importance is emphasized of defining the method of polymerization used for obtaining polymer samples for which physical studies are reported in this field. FACTOKS CONTROLLING PROPERTIES OF NONRIGID POLYMERS
Certain mono-olefinic compounds, such as isobutylene, and rc-butyl acrylate yield high polymers which exhibit rubberlike properties to a degree a t ordinary temperatures. I n contrast to cross-linked or vulcanized rubbers, these elastomeric high polymers are thermoplastic and the degree of thermoplasticity
EFFECTS O F SIDE CHAIN AND DEGREE O F POLYMERIZATION
Vinyl alkyl ethers derived from lower alcohols polymerize rapidly under the influence of Friedel-Crafts type catalysts ai room temperature or higher temperatures t o give primarily balsamlike or viscous liquid products ( 3 5 , 3 6 ) . These polymers, which are generally of comparatively low viscosity, are not considered in this paper, except t o point out t h a t viscous liquid polymers are obtained unless special procedures and precaution? are followed. A solid polymer was obtained by Mueller-Cunradi and Pieroh
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November 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
(30) from highly purified vinyl isobutyl ether a t moderately Low temperatures. Both boron trifluoride and boron trifluoridedialkyl ether complexes were disclosed as catalysts for this reaction. Neither in this patent nor in s u b s e q u a t literature were detailed properties of these products discussed, and no evidence was presented t o the authors' knowledge to show t h a t under d s e r e n t conditions these polymerizations of vinyl isobutyl ether could yield different types of products having similar degrees of polymerization. German investigators apparently believed that from a given vinyl ether monomer the higher the degree of polymerization the more firm and less tacky was the polymer in all cases. Otto et al. (Sf) described an apparatus for continuous polymerization of isobutylene and vinyl isobutyl ether. Semisolid or solid products were obtained by rapid reaction a t low temperatures using liquid ethylene or propane as diluent and boron trifluoride as catalyst. This type of apparatus was used in Germany for the manufacture of Oppanol B (polyisobutylene) and Oppanol C (rubberlike polyvinyl isobutyl ether). Rubberlike high polymers were prepared from vinyl n-butyl ether by Zoss (38). Vinyl n-butyl ether does not yield solid or rubberlike polymers by the procedures of Muelier-Cunradi or by that of Otto. I n general, the high polymers of vinyl n-butyl ether resemble Oppanol C, in spite of the fact that the method of polymerization more closely resembles t h a t for the nontacky, more crystalline form of polyvinyl isobutyl ether. Table I shows a comparison of some of the properties of polyisobutylene, polyvinyl n-butyl ether, and the two types of polyvinyl isobutyl ether. Mueller-Cunradi and Pieroh (299) have disclosed that by polymerization a t low temperatures, vinyl ethers having highly branched alkyl groups yield relatively firm polymers. Monomers of the type (RsC)2CHOCH=CH2 are said to give polymers outstanding in hardness compared t o polymers from vinyl alkyl ethers having unbranched alkyl groups. A solid high polymer of vinyl isopropyl ether is disclosed in an I. G. report and has been given the name Oppanol E (38). Here, a t the General Aniline and Film Corporation's Laboratory, solid polymers (form stable a t room temperature) have been prepared also from vinyl methyl ether, vinyl ethyl ether, vinyl n-propyl ether, and vinyl sec-bubyl ether. Polymers from very long-chain vinyl alkyl ethers are waxlike solids even when the polymer viscosity is comparatively low as obtained by polymerization near room temperature. An example is polyvinyl octadecyl ether ( I 4 ) . TWO TYPES O F IONIC OR FRIEDEL-CRAFTS POLYMERIZATION
The polymerization of vinyl isobutyl ether to obtain Oppanol
C has been described in reports issued under the sponsorship of the U. S. Government (8, 9,IS, 46). Boron trifluoride catalyst (0.01 % or more) dispersed in liquid propane is brought into contact with highly purified vinyl isobutyl ether diluted with liquid propane in such a way that nearly inatantaneous polymerization occurs. The temperature is limited by the vaporization of propane. As the pressure remains near atmospheric, it is believed that the temperature during polymerization may be near -40" C., the boiling range of liquid proT o the monomer before polymerization is added as a stailizer, a small amount of an alkyl phenol sulfide such as bis(2-hydroxy-5-tert-butyl phenyl) sulfide (2 9). The Oppanol C type polymerization was simula'ted in this laboratory by quickly pouring liquid propane containing boron trifluoride into a beaker containing vinyl isobutyl ether diluted wit! I t o 2 parts of li uid propane. Both liquids were brought to -60 or -70" C. belore mixing. The reaction occurred almost instantly with a puff from gaseous propane; the polymer formed faster than the eye could follow and part of the white solid polymer was often blown into the air. Oppanol C type polymers prepared in this laboratory are designated Oppanol C-GAF in this paper. This type of polymerization reaction is referred t o as Baah polymerization. Intelligence reports from Germany (8, $1, 46)indicate that the flash polymerization of vinyl isobutyl ether using the type of apparatus dcsrribed by Otto et al. occurs even
.
gsne
2105
TABLE I. PROPERTIES OF POLYISOBUTYLENE AND POLYVINYL BUTYLETHERS
poiyiso- polyvinyl Polyvinyl Ethers Isobutyl butylene n-ButylB-100 ether OppanolC PVI Tacky Nontacky Tacky Tacky Adhesion at 25" C. Extensibility RubberRubber- Rubber- Cold draw, like" like" like" a t 200 to 400 Ib./sq. in. Milling at 2 5 O C. Breaks Breaks Breaks Little change down down down (quiet) Hardness (A-2 instant) b 16 13 14 62 Brittle point, e CO -70 - 65 -22 -18 0.93 0.93 Snecifio eraviW 0.91 0.93 RefractiGe index. n n d 1.51 ... 1.45 1.46 Stable Stable Stable Stable Effect of aqueous alkali Effect of dilute aqueous Stable Stable Stable Stable acids Water absorption (24 hr., 0 . 0 0.32 0.64
...
2 5 O C.) a Reversibly extensible for moderate deformations, cold flow occurring BO
higher deformations depending on moleoular weight. b Penetration hardness by Shore A-2 instrument (similar to A.S.T.M. D314-39). 6 Some variation with molecular weight. d Approximate values of room temperature using polymers oontaining stabilizers.
more rapidly than that of isobutylene. I n the case of vinyl isobutyl ether, polymerization largely occurs in the space above the belt, whereas for the continuous preparation of polyisobutylene (Oppanol B) polymerization occurs on the belt. The more crystalline, nontacky polyvinyl isobutyl ethers o b tained by relatively slow polymerization (using boron trifluoridedialkyl ether complexes as catalysts) are designated as PVI in this paper. The following procedure is a typical method of preparing this type of polymer. To a mixture of 1 part purified vinyl isobutyl ether and 3 to 5 parts of li uid propane a t -8OOto -60" C. and under agitation in a close3 Pyrex vessel, there was added dropwise 1% or less boron trifluoride-diethyl ether or other ether complex of boron trifluoride. The catalyst complexes were carefully distilled before use and precautions were taken t o avoid local rapid reaction and temperature rise near the point of mixing of the catalyst and monomer-propane. I n some of these experiments dry ice was applied inside the reaction vessel as well as in the outside cooling bath. No special precautions were taken t o exclude air and water vapor. The purification of vinyl isobutyl ether monomer has been described in a previous paper (88). The slow polymerization reactions were completed in a period of 0.5 to 2 hours after the addition of the last portion of catalyst. During this time growing masses of the polymer were visible as a separate phase suspended in the monomer-propane mixture. The antioxidant stabilizer employed was 0.5% N (p-hydroxyphenyl) morpholine. The stabilizer either was dissolved initially in the monomer or applied after the neutralization of the catalyst. At the end of both the Oppanol C-GAF and PVI polymerizations, there was added an excess of alkali dissolved in a mixture of water and methanol. This treatment deactivated the catalyst, removing catalyst residues and yielding the polymer in a nonadhesive form more easily handled after coming to room temperature. None of thesc factors is as important in determining the character of the polyvinyl isobutyl ether formed as are the catalyst and the method of applying the catalyst. This second type of polymerization is characterized by the relatively slow growth of polymer around the catalyst in a separate phase. By controlling factors, such as the temperature, monomer purity, diluent concentration, and rate of addition of catalyst, a series of both types of polyvinyl isobutyl ethers was prepared. However, because of the complexity of these polymerizations, it was not always possible to predict precisely the polymer viscosity obtained. Vinyl isopropyl ether also undergoes both types of polymerization to give two types of polymers, but these products were not studied in detail. I n Table I1 are given viscosity values qsp/C of samples of polyvinyl ethers and polyisobutylene which were examined. These were determined using solutions of 0.10 gram per 100ml. of benzene a t 25' C. in a Ubbelohde type viscometer. In this paper the nontacky type polyvinyl isobutyl ether of viscosity q s p / C = 0.40 is abbreviated PVT (0.401 : the highest viscosity
INDUSTRIAL AND ENGINEERING CHEMISTRY
2106
TABLE 11. VISCOSITIES O F
POLYhlER
SAMPLES EXAMINED
(Solutions of 0.10 gram of polymer per 100 ml. of benzene were used in a Ubbelohde viscometer a t 25' C . ) Partially Crystalline Polyvinyl Amorphous Type Polyvinyl Isobutyl Isobutyl Ethers (Nontacky) Ethers (Tacks) ?SP/C
PVI 1527-15 P V I 302 P V I 1527-16 PVI 1527-10 PVI 1527-11 P V I 1527-23 Polyisobutylene B-100 Polyisobutylene B-140
0.40 1.5 3.8 6.4 8 ,6 9.1
0.8 1.5
SSP/C
-
Oppanol C-GAF 142-3 142-5 Oppanol C (K 100) Oppanol C (K = 130) Oppanol C (commercial) Oppanol C-GAF 142-1 Polyvinyl n-Butyl Ethcr P V N 235
2.2 2.5 2.7 3.4 2.7 to 4 , 3 4.6 5.4
polymer of this type is designated as P V I (9.1). Oppanol C-GAF type polyvinyl isobutyl ethers having viscosities q s p / C = 2.2 to 4.6 were prepared. The viscosity of Oppanol C samples are ordinarily expressed abroad as K values of Filrentscher (28). I n the manufacture of Oppanol C, it was sought to obtain a K value of about 120. German samples which were examined showed a considerable viscosity range. Breakdown on aging probably accounts for part of this variation as well as differences from one part of a polymer mass t o another. FRACTIONATION
By portionwise addition of ethanol t o 57Gsolutions of the polymers in a mixture of equal parts of toluene and methyl ethyl ketone it was attempted t o obtain a series of fractions from samples of both types of polyvinyl isobutyl ether. After sufficient nonsolvent had been added t o show incipient precipitation or opalescence, the mixture was heated t o 40" or 50" C. and allowed to cool gradually t o near room temperature by placing in an opentop Dewar flask overnight. Although a number of solvent s ) ~ tems were tried, Oppanol C would not give a seiies of fractions of uniform size; the first fraction was much larger than all the otheis together in every case. Even when very small amounts of nonsolvent were added near the precipitation point, either all of the polymer remained in solution or the largest part separated as one fraction. I n one fractionation experiment using Oppanol C, the first fraction comprised 80% of the recovered polymer and the second fraction 15%. These fractions were similar in viscosity to the unfractionated polymer. They were tacky and rubberlike, little different from the commercial Oppanol C. (Commercial Oppanol C was treated with talc t o prevent adhesion in storage. Unless otherwise stated, the talc had been removed from the Oppanol C.) A third fraction of 4% RTas considerably softer and tacky whereas about 1%of a viscous sticky liquid compiised the fourth and last fraction. Judging from this method of fractionation, the sample of Oppanol C was quite homogeneous; this seems remarkable considering the flash type of polymerization by which it was formed. The possibility must be considered that, in such a solvent fractionation precipitation may occur as a function of chain shape as well as chain length. Oppanol C might then be less homogeneous than these experiments suggest because the chain shape may not lend itself t o separation by
OF POLYVIKYL ISOBUTYL ETHERS TABLE111. FRACTIONATIOX
iI
Per Approximate Cent Mol. Wt.a 34 330,000 49 160,000 13 95,000 3 ...
Fraction 1 Tacky, rubberlike Fraction 2 Tacky, rubberlike Fraction 3 Taoky soft rubbery 30 min. Fraction4 Tacky: soft: rubbe:? Fraction5 1 .. Sticky, viscous liquid Fraction 1 49 600,000 Nontacky, solid Fraction 2 21 170,000 Nontacky solid PVI (1.5) unmilled Fraction 3 17 76,000 Nontacky: solid Fraction 4 13 65,000 Nontacky, waxy Fraction 5 trace Soft wax a Molecular weights were obtained b y light scattering (weight average) by comparison with a polystyrene of known molecular weight by P. P. Debye i n this laboratory, Values 8 0 obtained were not oorreoted for dissymmetry in angular scattering.
oppanol milled
i
.
...
Vol. 40, No. 11
solvent precipitation. However, other tests indicated homogeneity. Long treatment of Oppanol C on the rubber mill (30 minutes at room temperature in air) gave a softer and more sticky polymer which showed a comparatively wide range of molecular weight, in fractions. Approximate weight average molecular weights for the first three fractions from milled Oppanol C are shown in Table 111together with observations on the physical form of the dried fractions. A commercial sample of Oppanol C was found t o have a weight average molecular weight of 600,000, whereas PVI (1.5) gave 200,000 by the light scattering method (38). Molecular weights of fractions from unmilled P V I (1.5) are also shown in Table III. All these dried fractions were nontacky and none was rubberlike. The fractions of lowest molecular weight were soft waxes (not sticky). The weight average molecular weight data were obtained by P. P. Debye in this laboratory using solutions in benzene. The apparatus and procedure have been described (11). Oppanol C underwent more rapid change on the rubber mill near room temperature than did P V I (1.5). In rolling both the polymers, the use of an atmosphere of commercial tank nitrogen around the mill slightly retarded the breakdown. OTHER M E T H O D S O F ESTIMATING MOLECULAR W E I G H T 4 Y D HOMOGENEITY
-1thermal diffusion apparatus of the vertical concentric cylinder type designed by Debye and Debye (10, 41) was applied t o test the relative homogeneity of Oppanol C and samples of PVI. The separation of the cylinder n d l s was 0.5 mm., the length of the cylinders 12 inches, and the temperature gradient between the malls was approximately 50" C. I n each experiment 135 ml. of a solution of 0.500 gram of polymer per 100 ml. of toluene was employed to fill the apparatus. After 18 hours' operation, samples of solution were withdrawn from the top and bottom reservoirs and specific viscosities were observed at 25" C , using a n OstwaldFenske viscometer. Any difference between the specific viscosities indicated t h a t a change (concentration, molecular weight distribution, or both) had occurred. Portions of the solutions were then evaporated at 50" C. and from the redissolved polymers values of q s p / C were determined comparing the polymers in the top and bottom reservoirs. I n the experiments for which data are given in Table IV, the resulting polymer concentration in the bottom reservoir was reservoir. approximately one and one half times t h a t in the p:t I n the experiment using Oppanol C, the dried polymers from the two reservoirs were both rubberlike, Showed about the same degree of tack t o the finger, and values of ?sp/C were essentially the same. A sample of P V I showed a separation into polymers of different q s p / C when the same conditions of testing in the thermal diffusion apparatus were applied. The third experiment was designed t o test the ability of the diffusion apparatus, having these dimensions, t o separate a known mixture of P V I polymers.
TABLE
Iv.
THERMAL DIFFUSIONTESTSUSINQ P O L Y V I N Y L ISOBUTYL ETHERSOLUTIONS
Polymer Oppanol C P V I (1557-16) Mixture 1 t o 1 : PVI(0.40) PVI(9.l)
+
Top Solution, ?SP 1 .00 1.75
Bottom Solution, 1.81 2.88
2.96 3.90
Bottom Polymer, WPlC 2.94 4.76
1.10
2.72
1.40
3.73
SSP
Top Polymer, SSPlC
Ultracentrifuge data indicated t h a t a sample of tacky Oppanol C had a higher degree of polymerization than nontacky PVI. In a private communication, P. 0. Kinell reported t h a t PVI, lot 302, is lower in molecular weight than a commercial sample of Oppanol C,judging from intrinsic viscosity and sedimentation constants i n chloroform solution. Sedimentation constants in S units when extrapolated t o zero Concentration were about 13 for the PVI and about 16 for Oppanol C.
INDUSTRIAL AND ENGINEERING CHEMISTRY
November 1948 E40
-XPOLYMER' OPPANM. C
220-
0
h
SOLUTION VISCOSITY PVI-
160140-
20UBBELOHDE VISGOMETER
6.5
IO
IS
20
CONCENTRATION IN BENZENE, GIIOOML
Figure 1. Relation betweenvsp/C and Concentration for Solutions of Two Types of Polyvinyl 150butyl Ethers
The slope of the curve relating q s p / C withconcentration has been advocated as a n indication of chain stiffness ($66). Samples were chosen of Oppanol C and of PVI which had nearly identical viscosities (qsp)/C in benzene at low c o n c e n t r a t i o n . Viscosities u t o a concentration oF2.0 grams per 100 ml. using a Ubbelohde viscometer at 25' C. are given in Figure 1. The more c r y s t a l l i n e tvae of pG1yvinyl ether showed a much
$ ?$$:: ~~~~~r~~ gon than did Oppanol G.
Oppanol C followed airly closely the equation of Huggifis and Mark (17, $6)for high polymer fractions: 7splC
= 7
4- k$zC
The IC' value for Op anol C without fractionation was about 0.54. The curve for the !VI sample (unfractionated) suggested relatively stiff chains with a high value of IC', but did not follow the equation well. Some additional work on viscosity of solutions is not reported here indetaileitherbecausethe differences shown betweenthe types of polyvinyl isobutyl ethers were small or the interpretation was in doitbt. Determination of qsp/C in toluene a t 10" and a t 40' C. showed a slightly higher temperature coefficient for PVI (3.8) and PVI (8.6) than for Oppanol C. I n a series of solvents representing a range of chemical types, values of +p/C were observed at 25' C. for the three polyvinyl butyl ethers. As previously reported for PVN (16) c clohexane gave high values followed by toluene, benzene, and zeptane; in general, ketones and ethers gave intermediate values; and with some exceptions, the lowest valuesof qsp/C were obtained, using solvents of structure approaching nonsolvents (poor solvents). The latter also showed the greatest differences in solution viscosity between the two types of polyvinyl isobutyl ethers. As an example, in isobutanol, P V I (1.5) gave qsp/C = 0.6 whereas Oppanol C (4.3) gave 3.5, suggesting that isobutanol is more nearly a nonsolvent for PVI than for Oppanol C. TESTS OF TACK AND HARDNESS
TACK.As a more objective comparison of tack or pressuresensitive adhesion than obtained by hand tests and touch, a mechanically driven tackiness tester devised in this laboratory was applied (6). I n testing tack of GR-S rubber compositions using the tackiness tester two contacting surfaces of rubber were used. For the tests shown in Table V, the upper contacting surface was polished chromium plate because the adhesion be-
2107
tween two sheets of rubberlike polyvinyl ethers was too greet to be measured with the apparatus. The test sheets were molded between nonmoistureproof cellophane, using a Carver press. The polymer surface freshly stripped from cellophane was tested, using a contacting force of approximately 0.28 kg. and other conditions as already described for GR-S rubber. The tack of the P V I sheets was in most cases too small to be detected; that of milled Oppanol C exceeded the maximum reading of the scale. Oppanol C is supplied, in Germany, dusted with talc. Part of the increase in tack of Oppanol C after milling probably results from inc'orporation of the talc into the polymer. The precipitated Oppanol C was prepared by dissolving 10.0 grams of polymer in a mixture of 190 ml. of toluene and 130 ml. of methanol a t 60' C. After the addition of 100 ml. more of methanol and cooling a t room temperature, the polymer mass was separated and kneaded with 200 ml. of methanol. After drying at 50 O C. in vacuum, 8.4 grams of polymer were obtained; this retained the rubberlike qualities of Oppanol C and showed increased tack. The sample of reprecipitated polyvinyl n-but 1 ether prepared in a similar manner retained tack but gave 3bwer values than before precipitation. HARDNESS.I n Table VI are shown Shore hardness measurements a t room temperature on plane surfaces of molded samples. Commercial and laboratory samples of Oppanol C have penetration hardness in the same range as commercial polyisobutylenes (B-100 and B-140) and vinyl n-butyl ether high polymers. All samples of PVI showed a higher order of hardness and, in general, the highest viscosity samples of P V I had highest hardness. When readings were made over longer times, an indication of relative cold flow could be observed with the Shore A-2 instrument. The vinyl ether high polymers showed less tendency to cold flow than did the polyisobutylenes.
TABLE VI. HARDNESS O F P O L Y V I N Y L ETHERS (Indenter t w e Shore A2 Durometer") Instant isoReadings 61 62 81
10-Second Readings 53 58 73 5 6 7 11
12 14 15 15
13 10 13 16 16 20 Procedure was similar t o that of A.S.T.M. Method D314-3'2 using molded samples having flat surfaces a t room temperature. Q
TABLE V. AVERAGE TACK VALUESFOR POLYVINYL ETHERSA N D POLYISOBUTYLENE~ Tack Values in Kg. 5 sec. 10 see. Instant Polymer contact contact contact PVI ( 1 . 5 ) 0.00 0.00 0.01 0 00 PVI (3.8) 0.00 0.00 PVI ( 9 . 1 ) 0.00 0.00 0.00 Oppanol C-GAF ( 2 . 5 ) 0.27 0.50 0.59 0.10 0.21 Oppanol C ( 4 . 3 ) b 0.28 Above reprecipitated b 0 70 >0.78 > 0.78 Oppanol C (milled for tape) >0.78 > 0.78 > 0.78 P V N (13) 0.40 0.45 0.48 Above reprecipitated 0.29 0.22 0.31 Polyisobutylene (B-60) 0.45 0.53 0.56 a Tests run a t room temperature using improved model of tack tester described in (6). b Surfaoe not entirely free of talc.
"-.
40
IO
20
50
100
120
150
IO00
le00
1500
IOW(
TIME IN SECONDS
Figure 2.
Firmness Tests with Williams Plastometer at 25" C.
INDUSTRIAL AND ENGINEERING CHEMISTRY
2108
B
A
Oppanol C:
B
A
D
C
Figure 3.
Vol. 40, No. 11
D
C
Figure 4.
X-ray Diffraction Patterns of Two Types of Polyvinyl Isobutyl Ethers
Patterns of Unstretched Samples Havinp Different Polymer Viscosities
Oppanol C:
( A ) unstretched, ( B )stretched. PVI (1.5): (C) unstretohsd,
( A ) 3.4, ( B ) 2.7. P V I :
( C ) 1.5, (D)3.8
( D ) stretched
and ‘Old flovv, a asanother measure Of hardness, usually obtained from amorphous or glasslike materials, Under Williams parallel plate plastometer (46) was employed, using the same conditions, PVI gave diffractionpatterns in which intersamples of 2.0 grams especially prepared as folloKs, Sheets about ference effects appear as reasonably sharp lines with halos under0.020 inch thick of each polymer were molded between cellophane in a Carver press. From these sheets disks were cut with a lines ( ~3). i ~ ~ ~ ~ lying the stronger No. 11 cork borer, the cellophane was removed, and a pile of the Diffraction Patterns Of Oppanol indicated no pronounced disks wm latminated with slight pressure and heating to give a fibering when the samples were extended t o the breaking point cylindrical specimen. After placing the sample under the 5-kg. weight of the plastometer, the thickness was observed, first at However, in some cases extremely faint fiber diagrams appeared short intervals and then after longer periods up t o a total time of superimposed upon the halo pattern. These faint, but sharp IO 000 seconds. In Figure 2 are plotted the percentages of the lines are identical with the pronounced lines of PVI and indicate original thickness against the log of time. The slope of the lineq can be taken as a measure of cold flow a t 25’ C. (dashpot element) and the ordinate a t 10 second: ran be considered a3 the instant litld to c o m ~ ~ i r - ~ i ‘cprinx oii clement). Tlica viiiiplt’ of pol\ isoh-ylcne rwponded inore J o n 1y tlinri the i u b h i’ikc p o l \ n n v l ethers a t first, but after 10,000 seconds had cold flon.cd niore than the pol? vin? 1 ethers. In t h c tc>ts nirh the plastomcter, a t 2;’.C., thc sanip’c; of PVT show little d c f o r n i ~ r i o n That rhe\ are cornpaiativelv rip.i,l caii bc artiibutecl 10 e r e r g r hxrriers rolatcd t o the crystallization rficcrs Ivhich n i w l be overcome Iicfoie spiing or dashpot elements can he cffcctire. 3 - 1 (9.1) c\liibitcd hcre n bchavior intcrmc.A B c diate between PVI (1.5) and Oppanol C. Figure 5. Diffraction Patterns of Oppanol C after Heating and IIlilling
c
X-RAY DIFFRACTION STUDIES
The only reference found in the literature to a n X-ray : + u d y of Oppanol C ( 4 3 ) is a single sentenre atating that Oppanol C gave a cliffrrcnt type x-ray tliag’ H I I I iiom Oppanol B (polyisobutylene.). Ba!
