Polymers thianthrenes

A brownish-purple solid salt, T SbCls, made by reacting thianthrene with antimony(V) chloride at room temperature in chloroform (62BCJ1137, 62JCS4963 67BCJ2539), was shown, by comparison with a methylene chloride solution of the salt, to have the radical as free in the solid as in solution (69BCJ548). Antimony(V) chloride was used to oxidize a thianthrene-containing polymer, —[T—C(Ph)=C(Ph) presumably... 

The yield of PPS decreased when the reaction temperature was increased. This was partially due to the formation of the by-product thianthrene. Improved yields (86%) and molecular weights (M = 10,000) were obtained when two ethyl substituents (R = R = Et) were present. The increase in yield was attributed to both an increase in polymer solubility and a decrease in the formation of thianthrene by-products [113]. The... 

Fewer studies are dedicated to the thermai decomposition of poly(1,3-phenylene suifide). One such study [8] indicates the formation of a cyclic dimer (thianthrene) and some cyclic trimer. The same behavior is confirmed for the decomposition at 530° C when the polymer forms cyclic oligomers (trimer to heptamer in decreasing yield) [8],... 

Poly(imide)s with the dithiathianthrene group are accessible from the reaction of thianthrene-2,3,7,8-tetracarboxylic dianhydride aromatic diam-ines. Thianthrene-2,3,7,8-tetracarboxylic dianhydride can be synthesized via a nucleophilic aromatic substitution of A-phenyl-4,5-dichloro-phthalimide with thiobenzamide, thioacetamide, and sodium sulfide. The polymers obtained have a good thermal stability in air and nitrogen. The polymers are amorphous and have been found to be soluble only in H2SO4. 

Difluorothianthrene, i.e., 2,7-difluoro-9,10-dithiaanthracene, c.f. Figure 5.8, is a monomer for poly(aryl ether thianthrene)s. This monomer is a high melting crystalline solid that sublimes under reduced pressure, simplifying the purification for polymer S5mthesis. It can be condensed with a bisphenol to yield poly(aryl ether thianthrene)s. ... 

The poly(aryl ether thianthrene)s are flame resistant and exhibit a high refractive index of 1.61-1.70, depending on the wavelength and the corresponding bisphenol. For this reason, the polymers are interesting for optical applications. 

M. Yoneyama, R. A. Johnson, and L. J. Mathias. Thianthrene-containing polyimides with monomer formation via nncleophiUc aromatic substitution. J. Polym. Set, Part A Polym. Chem., 33 1891-1899,1995. 

Edson JB, Knauss DM. Thianthrene as an activating group for the synthesis of poly(aryl ether ttiianttirene)s by nucleophilic aromatic substitution. J Polym Sci Part A Polym Chem 2004 42(24) 6353-63. 

The major polymerization sequence probably is benzene, phenyl sulfide, thianthrene, phenylthiothianthrene, oligomers, and then polymer, as shown ... 

The major intermediate compound in the polymerization of benzene and sulfur is thianthrene and the same polymer can be made with thianthrene as the starting material. Therefore, the conclusion can only be that the polymer consists of thianthrene units connected by sulfide linkages with an... 

Wejchan-Judek et al. in 1984 obtained polymeric material from the condensation of thiophenol with thionyl chloride in the presence of various metal chlorides (Eq. 8). They considered the products to be poly(p-phenylene sulfide) although the polymers contained considerable amounts of oxygen and excessive amounts of sulfur. Previously,in 1981, the excess sulfur in a pol3nner prepared in the above process with AlCl was believed to be concentrated in blocks of thianthrene units each connected by two sulfide bonds (ladder structure) which, in turn, were connected by blocks of crystalline PPS. Again the evidence for preparation of PPS is tenuous. 

R.A. Johnnson, L.J. Mathis, Synthesis and characterization of thianthrene-containing poly(benzoxazole)s, J. Polym. Sci. Part A Polym. Chem. 33 (11) (1995) 1901-1906. 

FIG. 17-43, Relaxation spectra, reduced to 25 C, of four poly(vinyl chloride) gels in di-2-ethylhexyl phthalate (solid curves) and two gels im dimethyl thianthrene (dashed curves). Points top black, calculated from G bottom black, from G . Numbers denote polymer concentration in volume percent. O- 72-its... 

Thianthrene-Containing Polymers Polyimides, Aramids, and Polybenzoxazoles... 

More recently, thianthrene was synthesized from 1,2-dichlorobenzene with hydrogen sulfide at 550 C. This method is of particular interest since it demonstrates thianthrene formation in high yields from chloro-displacement reactions, and more importantly indicates thermal stability of the thianthrene nucleus well into the upper temperature range for high-performance polymers. 

Aliphatic polyamides were also prepared from the thianthrene diamines with aliphatic diacid chlorides. These polymers had increased solubility but decreased thermal stability relative to the all-aromatic polymers. 

Thianthrene-containing polyamides have also been prepared by reacting thianthrene-2,7-dicarboxylic acid chloride with aromatic and aliphatic diamines at low-temperature. The polymerization of thianthrene-2,7-dicarboxylic acid chloride and 1,4-phenylenediamine yielded 81% polyamide with an inherent viscosity of 0.75 dL/g, although no other polymers or characterization results were discussed. 

Thianthrene-containing polyamides were also prepared by converting thianthrene-containing polyketones to polyamides by Schmidt and Beckmaim rearrangements. These polymers derived had lower inherent viscosities relative to those prepared by the low-temperature reaction of diamines and diacid chlorides. 

TTie polyamides prepared here also have low crystallinity as determined by wide angle X-ray (no or weak crystalline peaks seen above strong broad amorphous bases). The thermal stability of thianthrene-based polymers may depend on the basic chemical structure (ie, thianthrene dicarboxylic acid derivatives give aramids which are more stable than those derived from thianthrene diamines) as well as on crystallinity, intermolecular interactions and polymer chain packing. However, the possibility of trace amounts of impurity within Ae thianthrene diamines could have significantly affected the onset of degradation in earlier polymers. 

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