Ind. Eng. Chem. Prod. Res. Dev., Vol. 18, No. 4, 1979 249
mission. AT is almost proportional to the transmission distance, and it is clear from the comparison between the measured wavelengths of 830 and 900 nm that the greater value of cy2 causes the narrow pulse width; from this, it is also clear that the eq 2 holds true. Figure 9 represents the relationship between the base bandwidth and transmission distance. The relationship in Figure 9 indicates that the above discussion applies. Mechanical Strength A quartz fiber has an intrinsic strength of 1000 kg/mm2 or more, but the practical strength of the fiber is lower than that. The reason is that practically there are slight flaws in the fibers; furthermore, the flaws in the fiber may be attacked by moisture in the environment or handling a bare fiber may cause flaws with the fiber, Hence it is necessary to protect the fiber from such flaws caused by handling and moisture and to maintain the initial strength. The cladding resin in the plastic-clad fiber provides not
only a function of transmission optics as a cladding but also a function of maintaining the mechanical strength of the fiber itself. Figure 10 shows a distribution of the mechanical strength of the plastic clad fiber. It is clearly seen from Figure 10 that the fiber can almost ideally preserve its strength. Conclusion Although the cladding resin of plastic-clad fibers shows great attenuation, the plastic-clad fiber provides a low transmission loss of 3 to 4 dB/km (at 830 nm) and a bandwidth of 20 MHz/km or more, which conform well with the theoretical assumption. It has a mechanical strength average of 450 kg/mm2 or more. Literature Cited Gloge, D., Appl. Opt., 10, (Oct 1971).
Received for reuiew April 19, 1979 Accepted June 26, 1979
11. Symposium on New Polymers, New Processes A. R. Gilbert ACS/CSJ Chemical Congress, Honolulu, Hawaii, April 1979
Polymers Derived from Carbon Dioxide and Carbonates Noboru Yamazaki" and Seiichi Nakahama Department of Polymer Science, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan
Fukuji Hlgashl Faculty of Engineering, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan
This article reviews a few novel polymer preparation processes operating directly from carbon dioxide or carbonates, which have been developed in the author's laboratory. Carbon dioxide was condensed with aryl diamines and gave polyureas under mild conditions by use of diphenyl phosphite and pyridine as condensation agents. Synthesis of carbonates from carbon dioxide and alkyl alcohols in the presence of tin catalysts is discussed. Dialkyl carbonates afforded polycarbonates with glycols, and diphenyl carbonate with phenol using the same tin catalyst. Diphenyl carbonate yielded selectively biscarbamates with diamines, followed by formation of polyurethanes with glycols. Polyureas were also prepared by the reaction of diphenyl carbonate and diamines in the presence of magnesium chloride.
Introduction The chemistry of carbon dioxide has recently received attention due to resource and environmental problems. New reactions of carbon dioxide such as carboxylation of active methylene compounds and ring-opening and addi0019-7890/79/1218-0249$01.0010
tion polymerization of epoxides have been developed in the field of organic and polymer chemistry (Inoue and Kobayashi (1973)). More recently, a convenient method for the preparation of polycarbonate from potassium carbonate and a,w-dibromides in the presence of crown ethers
0 1979 American Chemical Society
Ind. Eng. Chem. Prod. Res. Dev., Vol. 18, No. 4, 1979
250
Table I. Direct Polycondensation of Carbon Dioxide with Diamines b y Using Diphenyl Phosphite in Pyridinea
Table 11. Dialkylcwbonates from CO, and ROHa
polyurea CO,, yield, atm %
diamine ~Hz-@-Cn2--@NH2
NHz-@o--@
[
N
H
z
~
C
~
]
p
~Hz-@oz--@--
C
=
i
C
H
a
l
"2
NHz-@"z
z
0.58 1.45 2.02 2.24 1.15 0.55
98
0.22
catalyst
(PhO),CO
PhOCOOBu
20
100
0.51
20
100
1.87
BuSn( OPh), Bu2Sn(OPh), Bu,SnOPh Ph,Sn( OPh),
37.9 46.2 18.6 14.2
41.2 30.7 45.3 30.2
20
86
0.14'
20
100
0.09'
1
33
0.08
in pyridine ---+
40 '(2
+NHCNHR j n + (HO),P(OC,H,)
II
(EtO),CO 450 EtOH 5 100 10 170 (EtO),CO 660' EtOH 5 150 (BuO),CO 260 BuOH a Bu,Sn(OR),, 1 . 7 mmol; ROH, 5 mL, for 24 h. With 170 % MeOCOOEt. Based on Bu,Sn(OR),.
100 100 100 100 100 100
has been reported (Soga et al., 1979). This review refers to some novel condensation reactions of carbon dioxide and carbonates which have been developed in our laboratory and been extended to produce macromolecules. Polyureas from Carbon Dioxide a n d Diamines During the course of studies on models of biochemically related reactions, carbon dioxide has been found to couple with amines under mild conditions in the presence of diphenyl phosphite and pyridine in our laboratory (Yamazaki et al., 1975a). This process could be extended to produce polyureas directly from carbon dioxide with diamines under mild conditions: at less than 40 atm of carbon dioxide pressure and around 40 "C (Table I) (Yamazaki et al., 1975b).
+ HOC,H,
0
Polyureas of high molecular weight have generally been obtained from aromatic diamines and carbon dioxide. However, polymers from 4,4'-diaminodiphenyl sulfone and p-phenylenediamine showed low viscosity because the polymers produced had low solubility in the reaction medium. Aliphatic diamines with higher basicity afforded polymers of remarkably low molecular weight in low yields, presumably because of the formation of pyridine-insoluble and less reactive ammonium carbonates as reaction intermediates. The initial pressure of carbon dioxide and the reaction temperature affected the molecular weight of the resulting polyurea yielding a maxima of viscosity when the reaction is at 40 "C under a carbon dioxide pressure of 20 atm. Above this pressure, the viscosity decreased with the pressure, dropping at 40 atm to about one-fourth of that a t 20 atm. These unfavorable effects of both high tem-
%b
Bu,Sn(OEt), Bu,Sn(OMe), Bu,Sn(OBu),
5 10 15 20 30 40
20 46 0.13 a [Monomer] = 0.26 mol/L; [HO-P(OPh),] = 2.0 mol/ mol of monomer; at 40 "C for 4 h. I n HMPA at 30 "C. In H,SO, at 30 "C.
HOP(OC,H,),
yield, (R0)2C0
0.32
CHzNHz
+ H,NRNH, +
ROH
100
NHzcHz+Q
CO,
catalyst
product
1
1
"2
Qinh b
CO, Dress. . , kg/ temp, cm2 "C
Table 111. Yields of (PhO),CO and PhOCOOBu with Several Catalystsa yield, 5%
a Conditions: [PhOH]/[(BuO),CO] = 18.5; [(BuO),CO]/[catalyst] = 4.8, 200 " C , 550 mmHg, 8 h .
perature and high pressure upon the molecular weight may be caused by an inter- or intramolecular exchange reaction between polymers. The polyurea obtained from bis(paminopheny1)methane had high crystallinity and a melting point of 320 "C with slight decomposition and yielded from N-methylpyrrolidone (NMP)-LiC1 dope solution a fiber with a high tensile strength, 4g/d. Carbonates from Carbon Dioxide a n d Alcohols Reactions of carbon dioxide with dibutyltin dialkoxides yielding alkyl carbonates have been studied by Sakai et al. (1975). We have extended the reactions to produce carbonates from carbon dioxide with alkyl alcohols in the presence of di-n-butyltin dialkoxides. COZ + 2R'OH (R'O)zC=O + H2O R' = methyl, ethyl, n-propyl, and n-butyl The reactions were carried out in a 100-mL stainless steel autoclave under pressure from carbon dioxide. Results are shown in Table 11. The reaction is affected by temperature and catalyst. A maximum yield was given at 150 "C and with Bu,Sn(OBu),. Titanium tetraalkoxide catalyst was also active for the reaction, but less than dialkyltin alkoxides. Based on the experimental results, it is assumed that carboll dioxide is inserted into the Sn-0 bond of Bu2Sn(OR'),, followed by alcoholysis yielding carbonate and Bu,Sn(OH), which is again esterified by alcohol, so that the tin catalyst is reused. Removal of most of the water produced from the reaction mixture is necessary to give a higher yield of carbonates. Diphenyl Carbonate through Transesterification Diphenyl carbonate is an important material for the production of polycarbonate, which is produced commercially from phosgene and phenol. It was not prepared by the same process as in case of alkyl carbonate, but resulted easily through transesterification of alkyl to aryl carbonate, that is, from dialkyl or ethylene carbonates and phenol with the same type of catalyst such as dibutyltin diphenolate (Table 111).
-
(R'O),C=O
+
C,H,OH
CH 0 or I 'C=O CH20'
-200 O C
Bu,Sn(OC ,H ,),
(C,H,O),C=O
+
R'OH orCH,OH CI H 2 0 H
-
Ind. Eng. Chem. Prod. Res. Dev., Vol. 18, No. 4, 1979 251
Table IV. Polycarbonates from Butyl Carbonate and Diolsa diol
-
conditions
mol w t
5900
-(CH,), -
150 'C, 3 h
.CH2-@CH2-
180 "C/500 mmHg, 1 h
4
200 " C / 1 mmHg, 1 h
insol
180 C/500 mmHg, 1 h
-+
200 C/1 mmHg, 1 h
3900
200 " C / 1 mmHg, 0.5 h
4600
-CH2)2--@--
iH&rCH2,2-
150 " C / l mmHg, 0 . 5 h
CH3
&b
180 "C/150 mmHg, 5 h
-
CH3
200 OC, 2 h 1 5 0 "C, 4 h
+
200 " C / 1 mmHg, 2 h
Dibutyl carbonate, 50 mmol; diol, 50 mmol; Bu,Sn(OBu),, 0.26 mmol. dibutyl carbonate.
HO(CH,),OH HO(CH,),OH polyethylene glycol (mol wt 1000)
-(cH2)6-
8
+C-@-R-O-t,
a
HO-R-OH known process'
Polycarbonate
Q@H
C H O-C-NH-R-NH-C-@-C6H5 6 5 0
g
Po 1yur ea
MgC12
L
HO-R-OH
fC-O-R-O-C-NH-R-NHJn 0 0 Polyurethane
Figure 1. Polymers derived from carbon dioxide and carbonates.
Ethylene carbonate is known to result from carbon dioxide and ethylene glycol with iodine catalyst at around 100 "C. Polycarbonates from Dibutyl Carbonates and Diols Polycarbonates have been commercially produced from diols and phosgene or diphenyl carbonate. We have found that a dialkyl carbonate, such as dibutyl carbonate, was also able to yield polyaryl and -alkyl carbonates in the presence of dibutyltin dibutylate (Table IV).
+
HOROH - + + C O R 0 fn II
C
H
2
a
t5 - 0 - R - @-tn
NH2-R-NH2
n
(R'O)C=O
diol
Polycarbonate
MgC12 /I
biscarbamated
Polyurea
LA-
-(-NH-R-NH-CJ
Diphenyl carbonate was used in place of
Table V . Polyurethanes from Biscarbamates and Diolsa
T;i
Bu2Sn(0R')2
6300b 3300
+ R'OH
0
The molecular weights of polycarbonates obtained in this study were in the range of 3 4 X lo3, which is still not high enough for utility as a commercial plastic. In order to raise the molecular weight of the polymer, higher reaction temperature and exhaustive removal of the resulting butanol would be required. Polyurethane and Polyurea from Diphenyl Carbonate and Diamines It was interesting to find that diphenyl carbonate could be selectively aminolyzed with amines in the presence of 2-hydroxypyridine to yield phenyl N-aryl (or alkyl) carbamates in high yields, and the reaction was applied to the preparation of biscarbamate (I) by reaction with diamine (Yamazaki et al., 1979). Biscarbamate (I) led to a new route for producing polyurethanes when it was treated with
Q @?
yield, 5% qlinh 87 0.22 94 0.20 78 0.23
HO(CH,),OH
96
0.23
HO(CH,),OH
88
0.22'
HO(CH,),OH
94
0.30'
HO(CH, ),OH
85
0.11
CHa
a Monomer = 5 mmol; magnesium chloride = 0 . 5 mmol; pyridine = 1 0 m L ; temperature = 100 " C ; time = 20 h. I n hexamethylylphosphoramide (HMPA) a t 30 "C. C,H,OOCNH-R-NHCOOC, H,.
Table VI. Polyurea from Diphenyl Carbonate and Diaminesa diamine
n?N-@S02
yield, %
qinhb
80
0.23
91
0.44
86
0.14'
*NH2
n2Ncn2q 91
-d
CH2NH2
a Diphenyl carbonate = MgC1, = 0.01 mol; pyridine: 40 mL, reflux for 6 h . In HMPA a t 30 "C. ' In H,SO, a t 30 "C. Insoluble.
diol at 100 "C in pyridine in the presence of magnesium chloride. 2C6H,0COC,H, I1
+ NH,RNH,
---+
2-Ho-p~
0
C,H,OCNHRNHCOC,H,
I
+
HOROH
/I
II
0
0
3polyurethane
+
2C6H,0
252
Ind. Eng. Chem. Prod. Res. Dev., Vol. 18, No. 4, 1979
The results of the preparation of polyurethanes from various biscarbamates and diols in the presence of magnesium chloride are shown in Table V. No substantial changes in viscosity of the polymer from the biscarbamate of hexamethylene diamine were observed among diols. A substituent of methyl groups at the ortho position as in 2,4-diaminotoluene reduced the reactivity of the carbamate to the diol, affording polymer of low viscosity. Polyureas were also formed directly from diamines by use of diphenyl carbonate instead of carbon dioxide in the presence of magnesium chloride (Table VI) (Yamazaki et al., 1979).
All the processes described in this review are summarized in Figure 1. Literature Cited Inoue, S.,Kobayashi. M., Kagaku, 28, 942 (1973). Sakai, S.,Fujinami, T., Yamada, T., Furusawa, S.,Nippon Kagaku Kaishi, 10, 1789 (1975). Soga, K., Hosoda, S.,Ikeda, S.,J . Polym. Sci. Poly. Chem. Ed., 17, 517 (1979). Yamazaki, N.. Higashi, F., Iguchi, T., Tetrahedron. 31, 3031 (1975a). Yamazaki, N., Higashi, F., Iguchi. T., J . Polym. Sci. Polym. Chem. Ed., 13, 785 (1975b). Yarnazaki, N., Higashi, F., Iguchi, T., J . Polym. Sci. Polym. Chem. Ed., 17, 835 (1979).
Received for review April 20, 1979 Accepted August 23, 1979
M a l
H,NRNH, t C,H,OCOC,H, 4 polyurea il
0
This paper has been presented at the ACS/JCS Joint Meeting in Honolulu, Ha., Division of Polymer Chemistry, April 1979.
A New High Molecular Weight Polyphenylene Sulfide H. Wayne Hill, Jr. Phillips Petroleum Company, Research and Development, Bartlesville, Oklahoma 74004
In the preparation of polyphenylene sulfide from dichlorobenzene and sodium sulfide in a polar solvent, the use of an alkali metal carboxylate as polymerization modifier permits the production of a high molecular weight, soluble resin directly by polymerization. A separate curing or cross-linking step is eliminated from the usual process for producing injection molding resins. Molded specimens exhibit better tensile strength, elongation, impact strength, and resistance to cracking in thick sections than the more conventional resins produced by a combination of polymerizationand curing processes. Fibers, films, and sheet exhibit a combination of good mechanical properties, chemical resistance, and thermal stability.
Polyphenylene sulfide resins have been produced commercially by Phillips Petroleum Co. since 1973 by the process of Edmonds and Hill (1967). This process involves the production of poly(p-phenylene sulfide) from sodium sulfide and dichlorobenzene in a polar solvent. It involves the following steps: (1)preparation of sodium sulfide from aqueous sodium hydrosulfide and caustic in a polar solvent, (2) dehydration of the sodium sulfide stream, (3) production of polyphenylene sulfide from sodium sulfide and dichlorobenzene in the polar solvent, (4) polymer recovery, ( 5 ) polymer washing to remove byproduct sodium chloride, (6) polymer drying, and (7) packaging. The polyphenylene sulfide produced by the above process is a linear material of modest molecular weight and mechanical strength. It is useful as a coating resin and as a raw material for the preparation of injection molding resins by a curing process involving both chain extension and light cross-linking reactions (Hawkins, 1976). This curing process may be conducted in the solid state just below the melting point (285 " C ) of the polymer and in the presence of small amounts of air. The extent of curing is controlled through reaction temperature and residence time. Thus the preparation of injection molding resins from the uncured product of the polymerization reaction requires the following additional steps: (1)curing, (2) compounding with glass fibers and other fillers, and (3) pelletizing. We have now developed a new process (Campbell, 1975) which permits the production of a high molecular weight 0019-7890/79/1218-0252$01 .OO/O
Table I. Prouerties of Injection Molded Unfilled Resinsa cured high mol wt resin resin (uncured) property tensile strength, MPa elongation, % flexural modulus, MPa flexural strength, MPa izod impact, Jim notched unnotched heat deflection temp (264 psi), " C a
48.0 1.1 3845 104
78.5 21 3404 147
10.7 80.3 111
16.0 578 105
Properties measured on annealed specimens.
product directly in polymerization. This high molecular weight product is suitable for use as an injection molding resin as well as an extrusion resin for fibers and films without the use of a curing step in its production process. This method involves the use of an alkali metal carboxylate as a polymerization modifier and eliminates the need of the curing portion of the conventional process. It is possible to prepare an even higher molecular weight soluble polymer by the incorporation of a very small amount of a trichloro aromatic compound into the polymerization recipe. Steps in this new process include the following: (1) preparation of sodium sulfide from aqueous sodium hydrosulfide and caustic in a polar solvent containing an alkali metal carboxylate, (2) dehydration of the sodium 0 1979 American Chemical Society
