Macrocycles 27: Cyclic aliphatic polyesters of isosorbide

Numerous polycondensations of isosorbide and suberoyl chloride or other aliphatic dicarboxylic acid dichlorides were performed with pyridine as a catalyst and HCl acceptor. The reaction conditions were varied to optimize both the molecular weight and the fraction of cyclic oligo‐ and polyesters. Furthermore, we attempted to obtain the cyclic monomer by catalyzed back‐biting degradation of the molten cyclic polyesters above 220 °C in vacuo. The polyesters were characterized by viscosity and size exclusion chromatographic measurements as well as matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. In selected cases, mixtures of linear and cyclic polyesters were treated with a hot solution of partially methylated β‐cyclodextrin in methanol. This treatment allowed for a selective extraction of the linear chains up to approximately 5000 Da. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3414–3424, 2003     

Polymers of carbonic acid 32: Influence of catalysts on propagation and cyclization in the interfacial polycondensation of bisphenol A with diphosgene

Bisphenol A was polycondensed with diphosgene in a dichloromethane/aqueous NaOH system. Temperature, time, and molar ratios of the reactants were optimized according to a previously elaborated optimization of the hydrolytic polycondensation of bisphenol A bischloroformate. Five of the following catalysts were examined: triethylamine, 4‐(N,N‐dimethylamino)pyridine (DMAP), ethyldiisopropylamine (EDPA), tetrabutylammonium hydrogen sulfate, and triethylbenzylammonium chloride (TEBA‐Cl). Triethylamine and DMAP accelerated the hydrolysis of diphosgene by formation of a hydrophilic acylammonium salt. Therefore, the molecular weights decreased with higher concentration of these tert‐amines. However, the molecular weights increased (weight‐average molecular weight up to 10⁶) with higher concentrations of tetraalkylammonium salts because these catalysts favor chain growth in the organic phase via “naked” phenoxide ions without catalyzing the hydrolysis of diphosgene. EDPA gave poor results under all circumstances. Cyclic polycarbonates were discovered in all samples. Their fraction increased with the average molecular weight of the samples. When samples prepared with triethylamine or TEBA‐Cl were fractionated, cycles having molar masses up to 15,000 Da were detected by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 890–904, 2003     

New polymers of carbonic acid. XXV. Photoreactive cholesteric polycarbonates derived from 2,5‐bis(4′‐hydroxybenzylidene)cyclopentanone and isosorbide

Several binary copolycarbonates were prepared by polycondensation of 2,5‐bis(4‐hydroxybenzylidene)cyclopentanone, BHBC, with methylhydroquinone, MHQ, hydroquinone 4‐hydroxybenzoate, HQHB, or isosorbide. Furthermore, five ternary copolycarbonates were prepared based on the aforementioned monomers. All polycondensations were conducted in pyridine with trichloromethyl chloroformate as condensing agent. All polycarbonates were characterized by elemental analyses, viscosity and DSC measurements, IR and ¹H‐ and ¹³C‐NMR spectroscopy, optical microscopy, and the WAXS powder pattern. All isosorbides containing binary and ternary copolycarbonates were found to form a cholesteric melt, but only three of them were capable to form a stable Grandjean texture upon shearing. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1125–1133, 1999     

Polymers of carbonic acid. XXIV. Photoreactive,nematic or cholesteric polycarbonates derived from hydroquinone-4-hydroxybenzoate 4,4′-dihydroxychalcone and isosorbide

Numerous polycarbonates were prepared by means of “diphosgene” in pyridine using hydroquinone 4-hydroxybenzoate (HQHB) as mesogenic diphenol. In addition to the homopolycarbonate, binary copolycarbonates of HQHB and 4,4′-dihydroxychalcone (DHC) with varying molar composition were prepared. A series of ternary copolycarbonates were obtained by incorporation of isosorbide. Furthermore, an alternating copolycarbonate of HQHB and isosorbide was synthesized. All polycarbonates were characterized by inherent viscosities, elemental analyses, IR-, ¹H-NMR, and ¹³C NMR spectroscopy, by WAXS powder patterns DSC measurements, and optical microscopy with crossed polarizers. The homopolycarbonate of HQHB and most binary copolycarbonates were semicrystalline materials forming an enantiotropic nematic melt. Particularly noteworthy is the finding that the alternating copolycarbonate of HQHB and isosorbide forms a broad cholesteric phase despite the unfavorable stereochemistry of isosorbide. The ternary copolycarbonates containing isosorbide formed a cholesteric melt and a Grandjean texture upon shearing. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1611–1619, 1997     

Tuning the optical clarity of glass fiber‐reinforced polycarbonates by reactive blending with alternatives from biorenewable isosorbide

Optically transparent and mechanically strong glass fiber (GF)‐reinforced polycarbonate (PC) composites were fabricated via reacting with biorenewable isosorbide (ISB) moiety. While direct copolymerization of ISB and bisphenol A (BPA) by melt transesterification with diphenyl carbonate remained difficult due to the large discrepancy of reactivity and low thermal stability of ISB, we demonstrated in this work that ISB and BPA copolycarbonates with high molecular weight, low discoloration, and excellent optical transparency can be fabricated at 250 °C within 2.5 min by reactive blending of commercially available ISB‐based PC and BPA‐PC. A systematic study of synthesis, thermal degradation, and reactive blending of ISB‐containing PCs was performed to distinguish the reactivity between ISB and BPA, elucidate the effect of catalyst on chain scission, and testify the reaction mechanism of the unexpected asymmetrical inner–inner carbonate exchange. We clarified that the hydroxyl group on BPA exhibited a low reactivity and Lewis acid‐catalytic transesterification played a key role in preventing from the chain scission during the asymmetrical inner–inner exchange. Another unexpected factor that effectively suppressed the further chain scission was the miscibility of the ISB‐based PC with BPA‐PC once each chain on average was carbonate exchanged with its counterpart to form a “biblock” PC. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1670–1681     

Poly(ester urethane)s derived from lactide,isosorbide, terephthalic acid,and various diisocyanates

Isosorbide‐initiated oligomerizations of l ‐lactide were preformed in bulk using SnCl₂ as catalyst. The resulting telechelic OH‐terminated oligoesters were in situ subjected to simultaneous polycondensation and polyaddition with mixtures of terephthaloyl chloride and diisocyanates. Most polymerizations were conducted with 4,4′‐diisocyanatodiphenyl methane and 2,4‐diisocyanato toluene. The consequences of excess diisocyanate and four different catalysts were studied. The isosorbide/lactide ratio and the terephthalic acid/diisocyanate ratio were varied. Number average molecular weights up to 15 kDa with polydispersities around 3–5 were obtained. Depending on the chemical structure of the copolyester and on the feed ratio, incorporation of urethane groups may reduce or enhance the glass‐transition temperature, but the thermal stability decreases dramatically regardless of composition. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 867–875     

Cyclic poly(pyridine ether)s by the polycondensation of 2,6‐difluoropyridine with various diphenols

The bistrimethylsilyl derivatives of six different diphenols were polycondensed with 2,6‐difluoropyridine in N‐methylpyrrolidone in the presence of K₂CO₃. On the basis of previous studies, the reaction conditions were optimized for almost quantitative conversions. The feed ratio was systematically varied to optimize the molecular weight. A 2 mol % excess of 2,6‐difluoropyridine was needed to obtain maximum molecular weights. In the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectra of the optimized polyethers, only cycles were found (detectable up to 5000 Da). Obviously, the relatively low molecular weights obtained under optimized conditions resulted from a limitation of the chain growth by cyclization, indicating a high cyclization tendency for poly(pyridine ether)s. The size exclusion chromatography measurements not only proved low molecular weights but also demonstrated the existence of bimodal mass distributions and high polydispersities. Protonation of the poly(pyridine ether)s required strong acids such as methane or trifluoromethane sulfonic acid. The solubilities of the neutral and protonated polyethers derived from bisphenol A were studied in various solvents. The MALDI‐TOF mass spectra proved that protonation at 20–25 °C did not cause cleavage of ether bonds. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4781–4789, 2005     

Equimolar “a2 + b4” polycondensations—Cyclic polyethers derived from 1,4‐dicyanotetrafluorobenzene and various diphenols

Dicyanotetrafluorobenzene was polycondensed with bisphenol‐P, bisphenol‐M, or 1,4‐bis(4‐hydroxyphenoxy)butane in DMF. Either K₂CO₃ and ethyldiisopropylamine (EDPA) or tetramethyl piperidine (TMPD) was used as catalysts and HF acceptors. Regardless of base and concentration, all polycondensations of bisphenol‐P or 1,4‐bis(4‐hydroxyphenoxy)butane yielded more or less crosslinked polyethers. In the case of bisphenol‐M, all polycondensations conducted with K₂CO₃ and 0.4, 0.2, or 0.1 M monomer concentrations resulted again in gelation. Gels were also obtained when polycondensations of 0.4 M monomer solutions were catalyzed with EDPA or TMPD. Yet, at a concentration of 0.2 M, the amines yielded completely soluble polyethers, which were characterized by elemental analyses, inherent viscosities, MALDI‐TOF mass spectrometry, and DSC measurements. The mass spectra revealed that the soluble polyethers mainly consisted of cycles containing two C? F bonds per repeat unit. Nearly quantitative substitution of the C? F groups with 4‐chlorothiophenol, 4‐bromophenol, 4‐aminophenol, and 4‐phenyl azophenol proved successful, so that a broad variety of multifunctional polyethers was obtained, but in the case of 4‐chloro thiophenol cleavage of the polyether chain also occurred. © 2007 Wiley Periodicals, Inc. JPolym Sci Part A: Polym Chem 46: 543–551, 2008     

Fully bio-based thiol-ene photocured thermosets from isosorbide and tung oil

Direct preparation of coatings from neat vegetable oils without any pretreatment or modification is an elegant way of demonstrating the potential of renewable sources and it is also in line with the principles of Green Chemistry. In this work, photocured coatings were prepared from tung oil (TO), hazelnut oil (HN), and isosorbide. First, a dithiol derivative of isosorbide (ISTMP) was synthesized and then mixed with TO, HN, and a cationic photoinitiator. For comparison, formulations were also prepared by using two different commercial thiol compounds. Coating formulations were applied onto glass substrates and cured under UV light where oxidative polymerization and photoinitiated thiol-ene addition reactions took place concomitantly. Double bond conversion percentages, thermal degradation properties, water contact angles, and surface hardness of the coatings were determined. Furthermore, a model reaction between ISTMP and oleic acid was performed to prove that ISTMP reacts with the fatty acid. ISTMP containing formulation displayed a fast initial double bond conversion and its water contact angle value was found as 88 ± 3°. Rigid and thermally stable isosorbide ring improved both the thermal properties and the surface hardness of the coatings.     

Synthesis and properties of poly(isosorbide 2,5-furandicarboxylate-co-ε-caprolactone) copolyesters

Bio-based poly(isosorbide 2,5-furandicarboxylate-co-ε-caprolactone) (PIFCL) copolyesters were synthesized from 2,5-furandicarboxylic acid, isosorbide and ε-caprolactone. The obtained copolyesters were characterized by ¹H NMR, ¹³C NMR, intrinsic viscosity, GPC, DSC, TGA and tensile testing. The NMR characterization results confirmed the insertion of lactones units into poly(isosorbide 2,5-furandicarboxylate) (PIF) chains. All PIFCL copolyesters were amorphous with T_{D, 5%} higher than 300 °C. The glass transition temperatures of PIFCLs with FDCA molar ratio from 74% to 45% were within the range of 132.1 °C and 72.4 °C. Tensile testing revealed that introduction of ε-caprolactone into PIF chain imparted PIFCL with excellent mechanical performance, typically, PIFCL polyseter with FDCA molar ratio of 45% had a Young's modulus 858 ± 92 MPa, a tensile strength 44 ± 4 MPa and an elongation at break 480 ± 45%.     

Syntheses of Polyethers from Pentafluorobenzonitrile or Pentafluorobenzophenone and Flexible Diphenols

Cyanopentafluorobenzene (CPFB, pentafluorobenzonitrile) or pentafluoro‐benzophenone (PFBP) were polycondensed with long flexible diphenols at a 1∶1 feed ratio in the presence of K₂CO₃. A rather selective substitution of two C‐F groups was achieved with the formation of cyclic polyethers as the main products. Polycondensations of CPFB with flexible diphenols at 3∶2 feed ratio (a₂/b₃) yielded soluble multi‐cyclic polyethers by highly selective substitution of three C‐F groups. Yet, polycondensation at a feed ratio of 5∶2 gave a complex reaction mixture and substitution of all five C‐F groups was not observed. In all experiments, cyclization played a key role for the avoidance of gelation.     

Cyclic and telechelic ladder polymers derived from tetrahydroxytetramethylspirobisindane and 1,4‐dicyanotetrafluorobenzene

5,5′,6,6′‐Tetrahydroxy‐3,3,3′,3′‐tetramethylspirobisindane was polycondensed with 1,4‐dicyanotetrafluorobenzene in four different solvents at 70 °C. In dimethylformamide, N‐methylpyrrolidone, and sulfolane exclusively, cyclic polymers were detectable by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry up to masses around 13,000 Da. In dimethyl sulfoxide, linear byproducts were also found. Higher temperatures caused degradation reactions catalyzed by potassium carbonate. Polycondensations performed with the addition of 4‐tert‐butyl catechol or 2,2′‐dihydroxy binaphthyl yielded linear telechelic oligomers. Equimolar mixtures of linear and cyclic ladder polymers were examined by MALDI‐TOF mass spectra to determine how the end groups and the cyclic structure influenced the signal‐to‐noise ratio. The results suggested a preferential detection of the linear chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5344–5352, 2006     

Syntheses of multicyclic poly(ether sulfone)s from 5,5′,6,6′‐tetrahydroxy‐3,3,3′,3′‐tetramethyl spirobisindane and 4,4′‐bis(4‐chlorophenyl) sulfones

5,5′,6,6′‐Tetrahydroxy‐3,3,3′,3′‐tetramethyl spirobisindane (TTSBI) was polycondensed with 4,4′‐dichlorodiphenyl sulfone (DCDPS) or with 4,4′‐bis(4‐chlorophenyl sulfonyl) biphenyl (BCSBP) in DMSO. Concentration and feed ratio were optimized to avoid gelation and to obtain a maximum yield of multicyclic polyethers free of functional groups. Regardless of these reaction conditions, only low fractions of perfect multicycles were obtained from DCDPS apparently due to steric hindrance of ring closure. Under the same conditions high fractions of perfect multicycles were achieved with the longer and more flexible DCSBP. The reaction products were characterized by MALDI‐TOF mass spectrometry, ¹H‐NMR spectroscopy viscosity, and DSC measurements. Relatively low glass transition temperatures (T_gs ≈ 160–175 °C) were found. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3732–3739, 2008     

Insertion of Copper(II)/Schiff‐Base Complexes with NLO Properties into Commercial Polycarbonates by Thermal Processes

The preparation of a bisphenol‐A carbonate copolymer, containing Cu‐diimine units with nonlinear optical (NLO) properties, and its MALDI‐TOF mass spectrometric characterization are reported. Contrary to the usual synthetic method, NLO groups were inserted directly into a commercial polycarbonate by prolonged heating at 250 °C. This innovative procedure allows to obtain a Cu/diimine‐containing polymer of high molecular weight.

     

Polyimides based on new diamines having pendant imide groups

New aromatic diamines were prepared in two steps from 4,5‐dichlorophthalic anhydride and primary amines. The resulting 4,5‐dichlorophthalimide was reacted with 4‐mercaptoaniline, so that the chloroatoms were substituted by the mercapto groups (via the sulfide anions). The new diamines were polycondensed either with the diphenyl ether 3,3′,4,4′‐tetracarboxylic anhydride or with bicyclooctane tetracarboxylic anhydride. These polycondensations were conducted in boiling m‐cresol with azeotropic removal of water. The isolated polyimides were characterized by viscosity measurement, IR‐spectroscopy, elemental analyses, and MALDI‐TOF mass spectrometry. The mass spectra evidenced a high content of cyclic polyimides, indicating nearly perfect reaction conditions. The mass spectra also proved the formation of copolymers containing one diamine with a trialkylamine group in the side chain. High glass transition temperatures but a low crystallization tendency were found by DSC measurements. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6272–6281, 2005     

Microwave-assisted polycondensation of aliphatic diols of isosorbide with aliphatic disulphonylesters via phase-transfer catalysis

Numerous polycondensations of aliphatic diol of isosorbide and 1,8-dimesyloctane or other aliphatic dibromo and disulphonated alkylating agent was performed under phase-transfer catalytic conditions. In order to check the possible specific non-thermal microwave (MW) effects, reactions were comparatively performed inside a thermostated oil bath (Δ) under similar conditions. The reactions conditions were varied to optimize both, the fraction insoluble in methanol (FP MeOH) and the molecular weight of polyethers. In all cases, it was found that microwave-assisted polycondensations proceeded more efficiently compared with conventional heating (the reaction time was reduced from 24 h to 30 min: ratio 1/50). The polycondensation under microwave yields 63% of polyethers precipitating in methanol with relatively high average-weight molecular weights (M_w up to approximately 7000). The polyethers were characterized by NMR (¹H, ¹³C) and FT-IR spectroscopy and SEC measurement and MALDI-TOF mass spectrometry.     

Poly(hydroxyisobutyrate) by ring‐opening polymerizations of 5,5‐dimethyl‐1,3,2‐dioxithiolan‐4‐one‐2‐oxide

α‐Hydroxyisobutyric acid anhydrosulfate HiBAS (5,5‐dimethyl‐1,3,2‐dioxithiolan‐4‐one‐2‐oxide) was polymerized under various reaction conditions and the solid reaction products were characterized by ¹H NMR spectroscopy, MALDI‐TOF mass spectrometry (MT m.s.), fast atom bombardment mass spectrometry (FAB m.s.), viscosity, and SEC measurements. Thermal polymerizations at 100 °C mainly yielded cyclic oligo polyesters presumably resulting from a zwitterionic polymerization. Cycles were also detected when pyridine was used as catalyst at 20 °C. When triethylamine was used as catalyst traces of H₂O played the role of initiators. Benzyl alcohol initiated the polymerization of HiBAS at 100 °C and yielded a polyester terminated by one benzylester and one OH endgroup. The SEC measurements indicated that all samples possess relatively low molar masses with number–average molecular weights ≤ 10,000 Da (in contrast to the literature data). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6229–6237, 2008     

Preparation and Properties of Polyallenes. I. Polymerization of Allene by Ziegler-Type Catalysts

The polymerization of allene induced by organoaluminum-vanadium oxytrichloride catalysts has been investigated in aliphatic hydrocarbons and at normal pressure. For the catalysts investigated, the polymerization activity decreases at decreasing order of alkylation of the aluminum alkyl: AIR₃ > AIR₂X > AIRX₂ (R is Et or i-Bu; X is halogen). Compared with other aluminum trialkyls, trimethylaluminum shows a low activity. For the Al-i-Bu₃-VOCl₃ system, the effects of catalyst ratio, reaction time, and temperature have been studied.     

Syntheses of cyclic polycarbonates by the direct phosgenation of bisphenol M

Bisphenol M was subjected to interfacial polycondensations in an NaOH/CH₂Cl₂ system with triethylamine as a catalyst. Regardless of the catalyst concentration, similar molecular weights were obtained, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectra exclusively displayed mass peaks of cycles (detectable up to 15,000 Da). With triethyl benzyl ammonium chloride as a catalyst, linear chains became the main products, but the contents of the cycles and the molecular weights strongly increased with higher catalyst/bisphenol ratios. When the pseudo‐high‐dilution method was applied, both diphosgene and triphosgene yielded cyclic polycarbonates of low or moderate molecular weights. Size exclusion chromatography measurements, evaluated with the triple‐detection method, yielded bimodal mass distribution curves with polydispersities of 5–12. Furthermore, a Mark–Houwink equation was elaborated, and it indicated that the hydrodynamic volume of poly(bisphenol M carbonate) was quite similar to that of poly(bisphenol A carbonate)s with similar concentrations of cyclic species. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1248–1254, 2005     

Polymers of Carbonic Acid, 31. Cyclic Polycarbonates by Hydrolytic Polycondensation of Bisphenol‐A Bischloroformate

The hydrolytic polycondensation of bisphenol‐A bischloroformate in NaOH/CH₂Cl₂ was studied using triethylamine as the catalyst. Reaction conditions were optimized towards high molar masses. The isolated polycarbonates were characterized by means of SEC and MALDI‐TOF mass spectrometry. The fraction of cyclic polycarbonates strongly increased with higher molecular weights and in the best sample only cycles were detectable (up to 50 000 Da). The largest cycles can compete with cyclic DNS of microorganisms.