Sulfur-containing polymers. XVIII. Preparation and properties of thiuram polysulfide polymers

Thiuram polysulfide polymers have been prepared from alkali metal bisdithiocarbamates either by oxidation with ammonium persulfate or by polycondensation with sulfur chlorides. In some cases, isothiocyanate formation and/or thiourea formation were noticed. The polymer properties were significantly affected by the diamines used. Polymers derived from p-phenylenediamine decomposed gradually at room temperature with the liberation of elemental sulfur. Polymers based on aliphatic primary diamines were more stable. Piperazine gave the most stable polymer.     

Sulfur-containing polymers. IV. Preparation and properties of poly(sulfenyl thiocarbonates)

Poly(sulfenyl thiocarbonates) have been prepared for the first time by the stepwise condensation of chlorocarbonylsulfenyl chloride with diols and dithiols. The polymers were obtained in high yield. Generally they were crystalline solids and were soluble in chlorinated hydrocarbons. On treatment with benzyl mercaptan in the presence of triethylamine, the polymers afforded a diol, carbonyl sulfide, and a disulfide compound. This reaction was extended to the preparation of alternating copolydisulfides.     

Sulfur-containing polymers. VIII. Preparation and properties of poly(carbamoyl disulfides)

Poly(carbamoyl disulfides) have been prepared for the first time by the stepwise condensation of chlorocarbonylsulfenyl chloride with dithiols and diamines. The polymers obtained in high yields had inherent viscosities up to 1.86. The properties of the polymers depended primarily on the kind of diamines used. Some of the polymers gave transparent, tough films from chloroform solution. The polymer films decomposed by ultraviolet irradiation with liberation of carbonyl sulfide. All the polymers gradually became brittle during storage for 6–8 months under diffused light.     

Sulfur-containing polymers. VII. Alternating copolydisulfides

A variety of copolydisulfides have been synthesized in high yields by the fragmentation polymerization of bis(sulfenyl thiocarbonates) with dithiols in the presence of triethylamine. The structures of the copolymers were investigated by x-ray and NMR studies. Alkylene–arylene copolydisulfides were alternating. Alkylene–arylene copolymers derived from arylene dithiols were alternating, and those prepared from alkylene dithiols were generally random. It was concluded that the present procedure makes it possible to prepare various kinds of alternating copolydisulfides by using appropriate combinations of a bis(sulfenyl thiocarbonate) and a dithiol.     

Sulfur-containing polymers. VI. Preparation of poly[alkylene bis(oxycarbonyl) disulfides] and related polymers

Poly[alkylene bis(oxycarbonyl) disulfides] have been prepared for the first time by the reductive coupling of alkylene bis(oxycarbonylsulfenyl chlorides). Potassium iodide and a variety of transition metals or their salts were employed as reducing agents. Of these potassium iodide and cuprous chloride gave the best results. Pyrolysis, desulfurization. and thiol-induced fragmentation of the polymers have been studied. Homologous polymers, i.e., monosulfide polymer, trisulfide polymer, and tetrasulfide polymer, have been also synthesized. Monosulfide and disulfide polymers were highly crystalline solids. Trisulfide polymer was a white solid with a low degree of crystallinity. These polymers were soluble in chloroform and dichloromethane. Tetrasulfide polymer was a crystalline yellow solid and was soluble only in HMPA.     

Thermal degradation of polymers with phenylene units in the chain. II. Sulfur-containing polyarylenes

Poly(p-phenylene sulfide), a poly(arylene sulfone), and a poly(arylene sulfonate) were subjected to thermal degradation in vacuo, at temperatures between 250 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. The major decomposition product of poly-(phenylene sulfide) is a condensate, which consists of di- and trimeric chain fragments, dibenzothiophene, and possibly thianthrene. The residual polymer loses two thirds of its sulfur as hydrogen sulfide, however, one third is retained even at 620°C. The most characteristic decomposition reaction of the polysulfone and of the polysulfonate is the almost complete removal of the sulfur as sulfur dioxide. The elimination of sulfur dioxide is practically complete at 450°C for the polysulfone and at 350°C for the polysulfonate.     

Sulfur-containing polymers. V. Preparation of polyoxycarbonylsulfenamides by polycondensation of bis(oxycarbonylsulfenyl chlorides) with diamines

Polyoxycarbonylsulfenamides (POSA) have been prepared by interfacial polycondensation of bis(oxycarbonylsulfenyl chlorides) with diamines. The polymers obtained ranged in physical form from crystalline solids to resinous materials depending on the kind of both bis(oxycarbonylsulfenyl chlorides) and diamines used. Some of the polymers gave transparent pliable films from chloroform solution. The polymer films decomposed with liberation of carbonyl sulfide on being subjected to ultraviolet radiation.     

Macroreticular redox polymers. II. Further synthesis and properties of some redox polymers

A series of redox polymers was prepared by the addition of different redox groups to preformed, chloromethylated macroreticular styrene–divinylbenzene copolymers. These polymers contained the hydroquinone, hydroquinonesulfonic acid, methylhydroquinone, 2,5-dimethylhydroquinone, 2,5-dimethylhydroquinonesulfonic acid, 2,3,5-trimethylhydroquinone, tert-butylhydroquinone, chlorohydroquinone, benzyl mercaptan, anthraquinone, and the pyrogallol redox groups. Thus, a set of redox polymers is available having redox potentials that may range from approximately 150 to 700 mv.     

Sulfur-containing polymers. X. Aromatic poly(sulfenyl thiocarbonates)

Aromatic poly(sulfenyl thiocarbonates) have been synthesized by the interfacial polycondensation of bis(dithiocarbonyl chlorides) with bisphenols. Bisphenols having the hydroxyl groups on separate rings gave polymers in high yields. The inherent viscosities of the polymers ranged from 0.22 to 0.51. In general, they were soluble in chloroform, sym-tetrachloroethane, hexamethylphosphoramide, m-cresol, and dimethylformamide and formed transparent tough films on evaporation of chloroform solutions. Almost all of the polymers were amorphous and gave melt-spun fibers. The polymer films decomposed upon ultraviolet irradiation with liberation of carbonyl sulfide.     

D2-m-carborane-siloxanes. III. Preparation and properties of trifluoropropyl-modified polymers

Linear D₂-m-carborane-siloxanes with one, two, and three trifluoropropyl moieties per repeat unit were prepared by the condensation reaction between bisureidosilanes and carborane disilanol. Molecular weights between 100,000 and 220,000 were obtained. Compared to fluorosilicones, the trifluoropropyl-modified carborane-siloxanes exhibited greater thermal and oxidative stability and in certain cases comparable solvent resistance. The swelling index for carborane-siloxane elastomers decreased with increasing trifluoropropyl content, although this fluorocarbon moiety did compromise the thermal stability of the carborane system.     

Liquid crystal polymers. I. Preparation and properties of p-hydroxybenzoic acid copolyesters

High molecular weight copolyesters were prepared by the acidolysis of poly(ethylene terephthalate) with p-acetoxybenzoic acid and polycondensation through the acetate and carboxyl groups. The mechanical properties of the injection-molded copolyesters containing 40–90 mole- % p-hydroxybenzoic acid (PHB) were highly anisotropic and dependent upon the PHB content, polyester molecular weight, injection-molding temperature, and specimen thickness. As the injection-molding temperature increased and the specimen thickness decreased, the tensile strength, stiffness, and Izod impact strength increased when measured along the direction of flow of the polymer melt, and the coefficient of thermal expansion was zero. In some compositions these properties were superior to those of commercial glass fiber reinforced polyesters. Maximum tensile strengths, flexural moduli, notched Izod impact strengths, and minimum melt viscosities were obtained with polyesters containing 60–70 mole-% PHB. Higher oxygen indicies (39-40) and heat deflection temperatures (150-220°C) were obtained with 80–90 mole-% PHB.     

Liquid crystal polymers. I. Preparation and properties of p-hydroxybenzoic acid copolyesters

High molecular weight copolyesters were prepared by the acidolysis of poly(ethylene terephthalate) with p-acetoxybenzoic acid and polycondensation through the acetate and carboxyl groups. The mechanical properties of the injection-molded copolyesters containing 40–90 mole-% p-hydroxybenzoic acid (PHB) were highly anisotropic and dependent upon the PHB content, polyester molecular weight, injection-molding temperature, and specimen thickness. As the injection-molding temperature increased and the specimen thickness decreased, the tensile strength, stiffness, and Izod impact strength increased when measured along the direction of flow of the polymer melt, and the coefficient of thermal expansion was zero. In some compositions these properties were superior to those of commercial glass fiber reinforced polyesters. Maximum tensile strengths, flexural moduli, notched Izod impact strengths, and minimum melt viscosities were obtained with polyesters containing 60–70 mole-% PHB. Higher oxygen indicies (39–40) and heat deflection temperatures (150–220°C) were obtained with 80–90 mole-% PHB.     

Preparation and properties of polyhedral oligomeric silsesquioxane polymers

Polyhedral oligomeric silsesquioxane (POSS) polymers were synthesized by the dehydrogenative condensation of (HSiO_3/2)₈ with water in the presence of diethylhydroxylamine followed by trimethylsilylation. Coating films were prepared by spin‐coating of the coating solution prepared by the dehydrogenative condensation of POSS. The hardness of the coating films was evaluated using a pencil‐hardness test and was found to increase up to 8H with increases in the curing temperature. Free‐standing film and silica gel powder were prepared by aging the coating solution at room temperature. The silica gel powder was subjected to heat treatment under air atmosphere to show a specific surface area of 440 m² g⁻¹ at 100 °C, which showed a maximum at 400 °C as 550 m² g⁻¹. Copyright © 2011 John Wiley & Sons, Ltd.     

Functional polymers. II. Synthesis and properties of new polymeric cinchona alkaloids

New polymeric cinchona alkaloids having favorable structures and properties for asymmetric catalysts have been prepared by radical copolymerization of the alkaloids with acrylonitrile using azobisisobutyronitrile (AIBN) as an initiator. Of the many reaction solvents tried, dimethylformamide (DMF) was found to be the solvent of choice especially for a large-scale synthesis. Alkaloid monomers employed were free dalkaloids, such as quinine, quinidine, cinchonidine, and cinchonine, and modified ones including 9-O-ethoxycarbonylquinine and quinine salts. The copolymers were thermally stable powders, soluble in DMF and DMSO, and insoluble in common organic solvents. They were found to be converted into water-soluble polymeric alkaloids by hydrolysis with alkaline hydrogen peroxide.     

Functional polymers with cyclic ether moieties. II. Synthesis and properties of network polymers with tetrahydrofuran moiety

A tetrahydrofuran (THF)‐containing network polymer was prepared by the radical suspension copolymerization of a styrene (St)‐type monomer with THF moiety, St, p‐chloromethylstyrene, and divinylbenzene in a biphasic medium consisting of water and monochlorobenzene in the presence of acacia gum as a suspension stabilizer. The diameters of the obtained polymer beads ranged from 100 to 200 μm. The obtained network polymer showed higher swelling abilities in various organic solvents than a similarly prepared network polymer without THF moiety, and it was stable under oxidative, reductive, and basic conditions. In its derivations to polystyrene‐based resins with thioether alcohol and hydroxyl moiety, remarkable accelerations of reactions were observed as a result of the introduction of THF moiety. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 800–806, 2001     

Side-chain liquid crystalline polymers with silphenylene-siloxane main chains. II. Preparation and characterization of polymers containing biphenyl mesogens

Side-chain liquid crystalline polymers with poly(silphenylene-siloxane) backbones and 4,4′-biphenyl-containing pendant mesogenic groups have been prepared and characterized. Polymers with spacers having only three methylene groups were not liquid crystalline, LC, but those with spacers having eight methylene groups or more and a long terminal substituent were LC as indicated by an isotropization peak on the shoulder of the melting peak in the DSC thermogram and the appearance of a Schlieren texture on examination by polarized light microscopy. However, the LC behavior could not be confirmed by wide-angle X-ray diffraction, WAXD, because the crystalline pattern apparently remained up to the isotropization temperature, presumably because the melting transition and isotropization are too close. In contrast, polymethylsiloxanes with the same mesogenic side-chains revealed the presence of well-defined smectic phases by WAXD as well as by polarized light microscopy.     

Preparation of Water-Soluble Sulfur-containing Derivatives of Wood

The influence of conditions of alkaline activation on xanthation of pine wood with mechanochemical preactivation was studied. It was shown that the duration of alkaline preactivation and the amount of sodium hydroxide exert a decisive effect on the degree of conversion of wood. The resulting macromolecular compounds are soluble in aqueous alkaline solutions and form viscous solutions.     

Sulfur-containing polymers: Thermal behavior of copolymers containing thiocarbonate groups

The thermal behavior of polymers containing 1,3-phenylene and bisphenol-A moieties joined by thiocarbonate and/or carbonate groups was investigated from the point of view of both thermal transitions and the reactions which occur on heating at high temperature.For thermal transitions it was found that replacing bisphenol-A moieties by 1,3-phenylene moieties leads to a decrease in T_g and in the ability to crystallize. On the other hand, replacing carbonate groups by thiocarbonate groups leads to only a slight decrease in T_g.The degradation proceeds at a significant rate, under nitrogen, only at temperatures higher than 360°C and the first step seems to be the breaking of the S-carbonyl bond followed by evolution of CO and CO₂ and, to a lesser extent, of COS. At the same time sulfide moieties are formed.In the presence of oxygen the degradation pathway is more complex and seems to involve both thiocarbonate groups and peroxides; the latter originated from the thermooxidation of bisphenol-A moieties. Branched and crosslinked polymers, possibly resulting from these reactions, are less prone to gas evolution than the parent polymers, as shown by the shift in the TG curves towards higher temperatures.