Synthesis and characterization of novel photo‐crosslinkable fluorinated poly(phthalazinone ether)s for optical waveguides

A series of novel photo‐crosslinkable fluorinated poly(phthalazinone ether)s containing 1,1‐diphenylethylene segments in the polymer main chain, used for optical waveguide materials, were synthesized by polycondensation reaction of decafluorobiphenyl with a mixture of 4‐(4‐hydroxylphenyl)(2H)‐phthalazin‐1‐one (DHPZ), 4,4‐(hexafluoroisopropylidene)diphenol and 1,1‐bis(4‐hydroxyphenyl)ethylene (BHPE) as co‐reactant. The feed ratio of DHPZ to total bisphenols varied from 0 to 80 mol%, while that of BHPE remained at 20 mol% for all polymers. The obtained copolymers show good solubility in some common polar organic solvents. The resulting polymers were photo‐crosslinked after UV irradiation for 10 min in the presence of a photoinitiator. The cured polymers show good chemical resistance, high thermal stability (temperatures of 1% mass loss after curing of 472–496 °C under nitrogen) and high glass transition temperatures (160–249 °C) which could be further increased by about 10 °C after photochemical crosslinking. By adjusting the copolymerizing bisphenol content, the refractive indices of transverse electric and transverse magnetic modes (at 1550 nm) of films of the polymers were exactly tuned in the range 1.5029–1.5661 and 1.4950–1.5502, respectively. The propagation losses of the cured films were measured and found to be less than 0.3 dB cm^?1 at 1550 nm, indicating the promise of these materials for passive optical waveguide devices. Copyright © 2011 Society of Chemical Industry     

Thermal properties,adhesive strength,and optical transparency of cyclolinear poly(aryloxycyclotriphosphazenes)

Four cyclolinear poly(aryloxycyclotriphosphazenes) derived from poly[4,4′‐(isopropoylidene)diphenoxytetrachlorocyclotriphosphazene] and poly[4,4′‐(hexafluoroisopropylidene)diphenoxytetrachlorocyclotriphosphazene] were synthesized from the reaction of hexachlorocyclotriphosphazene (HCP) with 4,4′‐(isopropylidene)diphenol (bisphenol A) or 4,4′‐(hexafluoroisopropylidene)diphenol (bisphenol AF) in molar ratio 1 : 1 via a one‐step condensation polymerization. Subsequent reaction of the resulted chlorine‐bound polymers with adequate amount of the sodium salts of 4‐methoxycarbonylphenoxide or 4‐propoxycarbonylphenoxide yielded the corresponding chlorine‐free polymers, [poly(tetra‐4‐methoxycarbonylphenoxy)‐4,4′‐(isopropoylidene)diphenoxy cyclotriphosphazene] (MBACP), [poly(tetra‐4‐propoxycarbonylphenoxy)‐4,4′‐(isopropoylidene)diphenoxycyclotriphosphazene] (PBACP), [poly(tetra‐4‐methoxycarbonylphenoxy)‐4,4′‐(hexafluoroisopropylidene)diphenoxycyclotriphosphazene] (MBAFCP), [poly(tetra‐4‐propoxycarbonylphenoxy)‐4,4′‐(hexafluoroisopropylidene)diphenoxycyclotriphosphazene] (PBAFCP), respectively. The chemical structures were characterized by Fourier transformer infrared, ¹H, and ¹³C‐NMR. Thermal properties of polymers were investigated using DSC and TGA analysis. The obtained polymers were thermoplastic, having moderate T_g values in the range of 26–78°C and good thermal stability up to 350°C in N₂ and O₂ gases. The thermal decomposition of the isopropylidene‐containing polymers is a one‐step process, while that of hexafluoroisopropylidene‐containing polymers is a two‐step process. However, presence of the latter group in the polymers backbone showed negligible effects on the thermo‐oxidative stability. The adhesive strength was measured by lap‐shear strength test on glass–glass bonded joint and found to be in the range of 1.78–2.62 MPa, this property may be attributed to the physical interactions between glass–glass interfaces and the polar‐pendant units present at the polymers backbone. The products showed high optical transparency when they applied between two glass surfaces, the adhesive layers were colorless, with the UV cut‐off wavelength of 300–302 nm, and the maximum transparency of about 90% was observed within the wavelengths range of 400–700 nm. Because of their properties, the cyclolinear poly(aryloxycyclotriphosphazenes) synthesized in this study are recommended as potential candidates for high thermally stable, transparent adhesives required in industrial applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Organosoluble asymmetric aromatic polyamides bearing pendent phenoxy groups

This study focuses on the synthesis and characterization of new polyamides based on an aromatic asymmetric diamine‐containing phenoxy‐substituted benzophenone segment. Low‐temperature solution polycondensation reactions of this diamine with various aromatic diacid chlorides containing ether, hexafluoroisopropylidene or diphenylsilane groups resulted in polyamides with molecular weights in the range 102 900–113 200 g mol^?1. The structures of these monomers and the corresponding polymers were fully confirmed using elemental analysis and infrared and NMR spectroscopy. All polyamides were easily soluble at room temperature in polar aprotic solvents and even in less polar solvents such as tetrahydrofuran. The polymers showed excellent thermal stability, up to 385 °C, and displayed glass transition temperatures in the range 225–256 °C. All the polymers presented blue florescence upon irradiation with UV light and thus show promise for applications in electroluminescent devices. Copyright © 2011 Society of Chemical Industry     

Preparation and characterization of poly (ether ether ketone)s containing benzimidazolone units

A series of novel poly(ether ether ketone)s containing benzimidazolone groups (PNBEEKs) with precise structures in high yields were synthesized from various stoichiometric ratio mixtures of benzimidazolone, 4,4′-dihydroxybenzophenone and 4,4′-difluorobnzophenone via a C–N/C–O coupling reaction process using sulfolane as a solvent. The reaction was carried out at 210 °C in the presence of anhydrous potassium carbonate. The structures of the resulted polymers were characterized by means of FT-IR, ¹H NMR spectroscopy, ¹³C NMR spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. XRD studies revealed that the incorporation of benzimidazolone groups increased the crystallinity of the resulted polymers. At the same time, as the benzimidazolone unit content in the copolymer increased, the solvent resistance properties and thermal properties of the prepared polymers improved. The polymers showed high glass transition temperatures (T_g?=?126–221 °C) and high thermal stability (T_d5%?=?497–593 °C in nitrogen, 466–588 °C in air). Moreover, the resulted polymers showed good fluorescence properties and the fluorescence emission peak was 435 nm.     

Heat-resistant adhesive resins derived from bismaleimides and bisnadimides containing amide linkages

A novel class of bismaleimides and bisnadimides containing amide linkages in their backbones were synthesized and characterized. The synthesis of these polymer precursors was carried out by reacting a diamine containing amide linkages with maleic/nadic anhydride. They were alternatively prepared by reacting the monomaleamic/monoadiamic acid of an aromatic diamine (1 mol) with terephthaloyl chloride (0.5 mol) and subsequent cyclodehydration. The latter new preparation method circumvented the hydrogeneration necessary in the first method of synthesis. The monomers were characterized by infrared (IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Differential thermal analysis (DTA) of monomers showed that bisnadimide and bismethylnadimide were polymerized at lower temperatures than the corresponding bismaleimide. Thermogravimetric analysis (TGA) in nitrogen and air atmosphere revealed that all polymers were stable up to 321–363°C. Their char yield at 800°C under anaerobic conditions was 49–67%.     

Synthesis and characterization of fluorinated poly(imide–amide–sulfone)s

A series of new, fluorinated poly(imide–amide–sulfone)s has been synthesized by solution polycondensation of aromatic diamines containing sulfone groups with diacid chlorides incorporating both imide and hexafluoroisopropylidene units. These polymers are soluble in polar amidic solvents, and their solutions can be cast into colorless, thin, flexible films having good electrical insulating properties and high thermal stability. The dielectric constant value is 3.49–3.68. The decomposition temperature in air is 464–479°C, and the glass transition temperature is in the range 279–359°C. All these characteristics have been discussed and compared with those of related fluorinated poly(imide–amide)s which do not contain sulfone groups and with other imide polymers without hexafluoroisopropylidene units. © 1995 John Wiley & Sons, Inc.     

Synthesis,curing behavior and thermal properties of silicon‐containing hybrid polymers with Si−C≡C units

Three novel kinds of linear silicon‐containing hybrid polymers with Si?C≡C units were synthesized by polycondensation reactions using the Grignard reagent method. All the polymers were thermosetting, highly heat‐resistant, moldable and easily soluble in common organic solvents. The structure, curing behavior, thermal and oxidative properties were characterized using Fourier transform infrared spectroscopy, ¹H NMR, ¹³C NMR, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis. The results obtained can provide theoretical guidance for determining the curing of the resin system. In addition, the cured polymers exhibit excellent thermal and oxidative stabilities with temperatures of 5% weight loss (T_d5) above 480 °C and 450 °C in nitrogen and air respectively; the residues at 1000 °C were above 70.0% and 45.0% respectively. The thermal and oxidative stabilities of the polymers are attributed to a crosslinking reaction between the Si?H and C≡C bonds or C≡C bonds. These polymers have the potential for use as high‐temperature‐resistant resins and ceramic precursors. © 2013 Society of Chemical Industry     

Thermal stability,solubility, and fluorescence property of poly(arylene ether ketone)s bearing <Emphasis Type="Italic">N</Emphasis>-arylenebenzimidazole units

A series of novel random poly(arylene ether ketone)s containing N-arylenebenzimidazolyl groups with precise structures in high yields were synthesized from 2-(2′-hydroxyphenyl) benzimidazole and 4,4′-dihydroxybenzophenone with 4,4′-difluorobenzophenone via nucleophilic substitution polycondensation reaction using sulfolane as a solvent. The reaction was carried out at 210 °C in the presence of anhydrous potassium carbonate. The structures of the resulted polymers were characterized by means of FT-IR, ¹H NMR spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. X-ray diffraction studies revealed that the incorporation of N-arylenebenzimidazolyl groups decreased the crystallinity of the resulted polymers. As the benzimidazole unit content in the copolymer increased, the solubility and thermal behavior of the prepared polymers improved. The novel poly(arylene ether ketone)s exhibited glass transition temperatures (T _gs) in the range 188–237°C, and there was a good linearity relationship between T _g values and the content of benzimidazolyl groups. The 5% decomposition temperatures were within the range of 512–539 °C in nitrogen and 496–540 °C in air indicating their good thermal stability. Tensile tests of the films showed that these polymers have desirable mechanical properties. Moreover, the resulting polymers showed good fluorescence properties.     

Synthesis of poly(ether amide)s from p‐xylylene glycol and bis(ether nitrile)s

BACKGROUND: Poly(ether amide)s have been well studied in terms of improving the physical and thermal properties of aromatic polyamides. Poly(ether amide)s of high enough molecular weight to be useful for industrial purposes are generally difficult to prepare. The objective of this project was to introduce a simple and commercially feasible process to prepare poly(ether amide)s by a polymerization reaction at relatively low temperature. RESULTS: A series of poly(ether amide)s were prepared by direct polyamidation of p‐xylylene glycol with bis(ether nitrile)s via the Ritter reaction using concentrated H₂SO₄ in acetic acid. The synthesized poly(ether amide)s showed good solubility in polar aprotic solvents. The resultant poly(ether amide)s had inherent viscosities in the range 0.36–1.03 dL g^?1. The glass transition temperatures of the poly(ether amide)s were determined using differential scanning calorimetry to be in the range 190–258 °C. Thermogravimetric analysis data for these polymers indicated the 10% weight loss temperatures to be in the range 290–390 °C in nitrogen atmosphere. CONCLUSION: The Ritter reaction was applied for the synthesis of a variety of poly(ether amide)s with moderate to high molecular weights. This procedure provides a simple polymerization process for the convenient preparation of poly(ether amide)s in high yield at room temperature. Copyright © 2009 Society of Chemical Industry     

Studies of phosphonate‐containing bismaleimide resins. I. Synthesis and characteristics of model compounds and polyaspartimides

Two phosphonate‐containing bismaleimide (BMI) [(4,4′‐bismaleimidophenyl)phosphonate] monomers with different melting temperatures and similar curing temperatures were synthesized by reacting N‐hydroxyphenylmaleimide with two kinds of dichloride‐terminated phosphonic monomers. The BMI monomers synthesized were identified with ¹H‐, ¹³C‐, and ³¹P‐nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The phosphonate‐containing BMI monomers react with a free‐radical initiator to prepare phosphonate‐containing BMI polymers and also with various aromatic diamines to prepare a series of polyaspartimides as reactive flame retardants. The polymerization degrees of polyaspartimides depend on the alkalinity and nucleophility of diamines as chain extenders. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) were used to study the thermal properties of the phosphonate‐containing BMI resins such as the melting temperature, curing temperature, glass transition temperature (T_g), and thermal resistance. All the phosphonate‐containing BMI resins, except the BMI polymers, have a T_g in the range of 210–256°C and show 5% weight loss temperatures (T_5%) of 329–434 and 310–388°C in air and nitrogen atmospheres, respectively. The higher heat resistance of cured BMI resin relative to the BMI polymer is due to its higher crosslinking density. Since the recrosslinking reactions of BMI polymers and polyaspartimides occur more easily in an oxidation environment, their thermal stabilities in air are higher than are those in nitrogen gas. In addition, the thermal decomposition properties of polyaspartimides depend on the structures and compositions of both the diamine segments and the BMI segments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1919–1933, 2002     

An environmentally stable,electrical conducting polymer prepared from a conjugated,processable acetylenic monomer

The synthesis, properties, and polymerization of an acetylene terminated monomer are described. The monomer melts and is thermally polymerized at 150°C and then at 300°C in an air environment. From the liquid stage, the monomer can be fabricated into moldings, castings, and prepregs. As initially cured, the polymer is an insulator. By further thermal processing at elevated temperatures in an inert atmosphere, conductivity can be controllably introduced into the polymer; for example, at 600°C a conductivity of 3.3 (Ω-cm)^?1 is obtained. Exposure of these conductive polymers to either boiling water for 1000 h or temperatures 100°C below their maximum process temperature (400–500°C) for 500–800 h did not produce any significant change in conductivity.     

Novel poly(thiourea‐ether‐imide)s derived from 4,4′‐oxydiphenyl‐bis(thiourea): probing the possibility for high‐temperature applications

Our interest in the fabrication of high‐performance polyimides has led to thiourea‐substituted poly(thiourea‐ether‐imide)s (PTEIs) with good retention of thermal properties along with flame retardancy. A new aromatic monomer, 4,4′‐oxydiphenyl‐bis(thiourea) (ODPBT), was efficiently synthesized and polymerized with various dianhydrides (pyromellitic dianhydride, 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic dianhydride) via two‐stage chemical imidization to fabricate a series of PTEIs. The structural characterization of ODPBT and the polymers was carried out using Fourier transform infrared, ¹H NMR and ¹³C NMR spectral techniques along with crystallinity, organosolubility, inherent viscosity and gel permeation chromatographic measurements. PTEIs bearing C?S and ? O? moieties in the backbone demonstrated an amorphous nature and were readily soluble in various amide solvents. The novel polymers had inherent viscosities of 1.16–1.23 dL g^?1 and molecular weights of ca 90 783–96 927 g mol^?1. Their thermal stability was substantiated via 10% weight loss in the temperature range 516–530 °C under inert atmosphere. The polyimides had glass transition temperatures of 260–265 °C. Incorporation of thiourea functionalities into polymer backbones is demonstrated to be an effective way to enhance their thermal properties and flame retardancy. Thus, ODPBT can be considered as an excellent candidate for use in the synthesis of high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of poly(ether sulfone) copolymers

Poly(ether sulfone) copolymers I–V were synthesized by the nucleophilic substitution reaction of 4,4-dichlorodiphenyl sulfone with varying mole proportions of 4,4-isopropylidene diphenol (bisphenol A) and 4,4-dihydroxydiphenyl sulfone (bisphenol S) using sulfolane as the solvent in the presence of anhydrous K₂CO₃. The polymers were characterized by different physicochemical techniques. The glass transition temperature was found to decrease with increase in the concentration of bisphenol A units in the polymers. All polymers were found to be amorphous. Thermogravimetric studies showed that all the polymers were stable up to 400°C with a char yield of about 36% at 900°C in a nitrogen atmosphere. ¹³C-NMR spectral analysis reveals that bisphenol S-based triads are preferentially formed compared to bisphenol-A triads, indicating greater reactivity of bisphenol S toward dichlorodiphenyl sulfone. The overall activation energy for the thermal decomposition of bisphenol A-based polymer (1) is much higher than that of bisphenol S-based polymer ( II ). This was attributed to the modification of the backbone of polymer I during the initial cleavage of the C—CH3 bond of the isopropyledene group. Polymer II decomposes by cleavage of the C—SO2 bond. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 743–750, 1998     

Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

Preparation and characterization of poly(p-phenylenediamine-co-xylidine)

p-Phenylenediamine (PPDA) homopolymer and its copolymers with 2,3-xylidine (XY) were synthesized by oxidative polymerization using potassium persulfate as an oxidant in HCl medium at room temperature. The yield, intrinsic viscosity, and solubility of the polymers were significantly dependent on the monomer ratio. The resulting polymers were characterized by Fourier transform IR spectroscopy, ¹H-NMR spectroscopy, wide-angle X-ray diffraction, and thermogravimetry methods. The results showed that the number-average degree of polymerization of the PPDA homopolymer was 33 and the actual content of XY units in the copolymer was slightly higher than the feed XY unit content. The polymers were substantially amorphous and showed the strongest diffraction at a Bragg angle of 3°. The polymers exhibited a thermal decomposition temperature higher than 436°C, the maximum weight-loss rate was slower than 4%/min, and the char yield was larger than 24 wt % at 600°C in nitrogen. The activation energy of thermal decomposition for the polymers increased from 19 to 25 kJ/mol with increasing XY unit contents from 0 to 10 mol %. The polymers showed higher thermostability but lower activation energy of decomposition in nitrogen than in air. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3107–3116, 2001     

Synthesis,thermal degradation and dielectric properties of poly[2-hydroxy,3-(1-naphthyloxy)propyl methacrylate]

2-Hydroxy-3-(1-naphthyloxy)propyl methacrylate (NOPMA) monomer was synthesized from reaction of 2-[(2-naphthyloxy)methyl]oxirane with methacrylic acid in the presence of pyridine. The polymerization of NOPMA was carried out by free radical polymerization method in the presence of AIBN at 60 °C. The structure of monomer and polymer was characterized by ¹H-NMR, ¹³C-NMR and FT-IR spectroscopy techniques. The glass transition temperature and average-molecular weights of poly(NOPMA) were measured using differential scanning calorimetry and gel permeation chromatography, respectively. The thermal degradation behavior of poly(NOPMA) has been investigated by FT-IR studies of the partially degraded polymer and thermogravimetry. The cold ring fractions (CRFs) were collected at two different temperatures, initially fraction-1 (CRF₁) is from room temperature to 320 °C, and the other fraction-2 (CRF₂) is from 320 to 500 °C. The volatile products of the degradation were trapped at ?195 °C (in liquid nitrogen). All the fractions were characterized by FT-IR, ¹H and ¹³C-NMR spectroscopic techniques, and the cold ring fractions (CRFs) were also characterized by GC–MS. For the degradation of polymer, the major compound between products of CRFs is α-naphthol. The GC–MS, FT-IR and NMR data showed that depolymerization corresponding to monomer was not prominent below 320 °C in the thermal degradation of poly(NOPMA). The mode of thermal degradation containing formation of the major products was identified. The dielectric permittivity (ε′), the loss factor (ε″) and conductivity (σ_ac) were measured using a dielectric analyzer in the frequency range of 50 Hz to 20 kHz.     

Flammability of polyacrylonitrile and its copolymers II. Thermal behaviour and mechanism of degradation

Homopolymeric polyacrylonitrile and fibre-forming copolymers containing either vinyl acetate or methyl acrylate comonomer have been studied by thermal analysis (DSC, TGA and DTG) at various heating rates (10–100 K min^?1) and under air and nitrogen. Three well-defined pyrolysis stages have been observed which occur over the temperature ranges 250–350°C, 350–550°C and above 550°C. Each stage involves a competition between volatilisation and cyclisation or char-forming reactions which depends on heating rate and the presence or absence of oxygen. The well-established dominance of cyclisation in the 250–350°C temperature range obtained during carbon fibre production from acrylic precursors occurs only at low heating rates. At high heating rates, volatilisation dominates and this explains why acrylic polymers have high flammabilities when heating rapidly. The full pyrolysis mechanism has been semi-quantitatively analysed and the role that comonomers play discussed. This has enabled a fuller understanding of the potential burning behaviour of these polymers to be developed.     

Synthesis and properties of silicon-containing polyamides

A series of aromatic polyamides incorporating silicon together with phenylquinoxaline or with hexafluoroisopropylidene groups has been synthesized by solution polycondensation of a silicon-containing diacid chloride with aromatic diamines having phenylquinoxaline rings or hexafluoroisopropylidene groups. These polymers are easily soluble in polar aprotic solvents, such as N-methylpyrrolidinone and dimethylformamide, and in tetrahydrofurane, and can be solution-cast into thin, transparent films having low dielectric constant, in the range of 3.26 to 3.68. These polymers show high thermal stability with decomposition temperature being above 400°C and glass transition temperature in the range of 236°C to 275°C. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1533–1538, 1997     

Poly(benzoxazinone-imide)s and poly(benzoxazinone-phenylquinoxaline-imide-amide)s containing hexafluoroisopropylidene units

Fluorine-containing poly(benzoxazinone-imide)s and poly(benzoxazinone-phenyl-quinoxaline-imide-amide)s have been synthesized by solution polycondensation of di-acid dichlorides containing imide and hexafluoroisopropylidene groups with 4,4′-di-aminodiphenylmethane-3,3′-dicarboxylic acid or with mixtures of the latter with a di-amino phenylquinoxaline. These polymers show high thermal stability, the decomposition temperatures being in the range of 450–470°C. Transparent flexible films were cast from the solutions of the corresponding polyamidic acid intermediates that after thermal cyclization showed low dielectric constant which recommends them for future applications in microelectronics.     

Examining the preparation and characterization of coatings based on linear aromatic terpoly(methoxy‐cyanurate‐thiocyanurate)s

Two series of terpoly(methoxy‐cyanurate‐thiocyanurate)s based on thiodiphenol and dithiodiphenyl sulfide and on dihydroxydiphenyl ether and dithiodiphenyl ether, were prepared in good yield and purity and fully characterized. Most of the resulting polymers, formed at room temperature using phase transfer catalysis, can be cast into films with good resilience and thermal stability (some examples suffer practically no mass loss when held isothermally at 190 °C and only display appreciable losses when held continuously at 225 °C). Char yields of 53%?61% are achieved in nitrogen depending on backbone structure. Some problems were encountered with solubility, particularly with copolymers, which limited molecular weight analysis, but values of M_n = 8000–13 000 g mol^?1 were obtained for the polymers based on thiodiphenol and dithiodiphenyl sulfide, and M_n = 5000–13 000 g mol^?1 for the polymers based on dihydroxydiphenyl ether and dithiodiphenyl ether. DSC reveals polymerization exotherms with maxima at 184–207 °C (ΔH_p = 43–59 kJ mol^?1), which are believed to be due to isomerization of the cyanurate to the isocyanurate (activation energies span 159–195 kJ mol^?1). Molecular simulation shows that diphenylether and diphenylsulfide display very similar conformational energy surfaces and would therefore be expected to adopt similar conformations, but the diphenylsulfide offers less resistance to deformations that increase the proximity of the two phenyl rings and results in more resilient films. © 2013 Society of Chemical Industry