Biodegradable polycarbonates containing side carboxyl groups—synthesis,properties, and degradation study

The main objective of the presented research was to synthesise biodegradable aliphatic polycarbonates containing reactive carboxyl pendant groups and to examine the influence of the copolymer chain microstructure and composition on the process of their hydrolytic degradation and cytocompatibility. The work describes copolymerization of cyclic trimethylene carbonate derivative containing benzyl‐ester pendant group (benzyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate) with trimethylene carbonate. The copolymerization was conducted with the use of zinc (II) and lanthanum (III) acetylacetonates as ring‐opening polymerization coordination initiators. Detailed NMR analysis allowed to define the microstructure of the obtained copolymers, which depended on the composition and type of used initiator. The final tapered chain microstructure of the obtained copolymers was related to huge differences in comonomers reactivity and evidenced low level of transesterification of the main copolymer backbone. Chosen copolymers, with unprotected carbonyl groups, were subjected to in vitro degradation test and cytocompatibility studies. It was found that high concentration of carboxyl groups resulted in copolymers which formed hydrogels and were very prone to hydrolytic degradation; they were also cytotoxic toward osteoblast‐like MG 63 cells. Copolymers with lower content of carboxyl groups were found less susceptible to degradation and cytocompatible with studied cells. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2756–2769     

Novel aliphatic poly(ester‐carbonate) with pendant allyl ester groups and its folic acid functionalization

A series of novel poly(ester‐carbonate)s bearing pendant allyl ester groups P(LA‐co‐MAC)s were prepared by ring‐opening copolymerization of L ‐lactide (LA) and 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one (MAC) with diethyl zinc (ZnEt₂) as initiator. NMR analysis investigated the microstructure of the copolymer. DSC results indicated that the copolymers displayed a single glass‐transition temperature (T_g), which was indicative of a random copolymer, and the T_g decreased with increasing carbonate content in the copolymer. Then NHS‐activated folic acid (FA) first reacted with 2‐aminoethanethiol to yield FA‐SH; grafting FA‐SH to P(LA‐co‐MAC) in the presence of TEA produced P(LA‐co‐MAC)/FA. The structure of P(LA‐co‐MAC)/FA and its precursor were confirmed by ¹H NMR and XPS analysis. Cell experiments showed that FA‐grafted P(LA‐co‐MAC) had improved adhesion and proliferation behavior of vero cells on the polymer films. Therefore, the novel FA‐grafted block copolymer is expected to find application in drug delivery or tissue engineering. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1852–1861, 2008     

Aliphatic poly(ester‐carbonate)s bearing amino groups and its RGD peptide grafting

This article deals with (1) synthesis of novel cyclic carbonate monomer (2‐oxo [1,3]dioxan‐5‐yl)carbamic acid benzyl ester (CAB) containing protected amino groups; (2) ring‐opening copolymerization of the cyclic monomer with L ‐lactide (LA) to provide novel degradable poly(ester‐carbonate)s with functional groups; (3) removal of the protective benzyloxycarbonyl (Cbz) groups by catalytic hydrogenation to afford the corresponding poly(ester‐co‐carbonate)s with free amino groups; (4) grafting of oligopeptide Gly‐Arg‐Gly‐Asp‐Ser‐Tyr (GRGDSY, abbreviated as RGD) onto the copolymer pendant amino groups in the presence of 1,1′‐carbonyldiimidazole (CDI). The structures of P(LA‐co‐CA/RGD) and its precursor were confirmed by ¹H NMR analysis. Cell experiments showed that P(LA‐co‐CA/RGD) had improved adhesion and proliferation behavior. Therefore, the novel RGD‐grafted block copolymer is promising for cell or tissue engineering applications. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7022–7032, 2008     

Cinnamate‐functionalized poly(ester‐carbonate): Synthesis and its UV irradiation‐induced photo‐crosslinking

A functionalized cyclic carbonate monomer containing a cinnamate moiety, 5‐methyl‐5‐cinnamoyloxymethyl‐1,3‐dioxan‐2‐one (MC), was prepared for the first time with 1,1,1‐tri(hydroxymethyl) ethane as a starting material. Subsequent polymerization of the new cyclic carbonate and its copolymerization with L ‐lactide (LA) were successfully performed with diethyl zinc (ZnEt₂) as initiator/catalyst. NMR was used for microstructure identification of the obtained monomer and copolymers. Differential scanning calorimetry (DSC) was used to characterize the functionalized poly(ester‐carbonate). The results indicated that the copolymers displayed a single glass transition temperature (T_g) and the T_g decreased with increasing carbonate content and followed the Fox equation, indicative of a random microstructure of the copolymer. The photo‐crosslinking of the cinnamate‐carrying copolymer was also demonstrated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 161–169, 2009     

Amphiphilic PEG‐grafted poly(ester‐carbonate)s: Synthesis and diverse nanostructures in water

Novel biodegradable amphiphilic graft copolymers containing hydrophobic poly(ester‐carbonate) backbone and hydrophilic poly(ethylene glycol) (PEG) side chains were synthesized by a combination of ring‐opening polymerization and “click” chemistry. First, the ring‐opening copolymerization of 5,5‐dibromomethyl trimethylene carbonate (DBTC) and ε‐caprolactone (CL) was performed in the presence of stannous octanoate [Sn(Oct)₂] as catalyst, resulting in poly(DBTC‐co‐CL) with pendant bromo groups. Then the pendant bromo groups were completely converted into azide form, which permitted “click” reaction with alkyne‐terminated PEG by Huisgen 1,3‐dipolar cycloadditions to give amphiphilic biodegradable graft copolymers. The graft copolymers were characterized by proton nuclear magnetic resonance (¹H NMR), Fourier transform infrared spectra and gel permeation chromatography measurements, which confirmed the well‐defined graft architecture. These copolymers could self‐assemble into micelles in aqueous solution. The size and morphologies of the copolymer micelles were measured by transmission electron microscopy and dynamic light scattering, which are influenced by the length of PEG and grafting density. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Synthesis and characterization of novel poly(ester carbonate)s based on pentaerythritol

Novel poly(ester carbonate)s were synthesized by the ring‐opening polymerization of L ‐lactide and functionalized carbonate monomer 9‐phenyl‐2,4,8,10‐tetraoxaspiro[5,5]undecan‐3‐one derived from pentaerythritol with diethyl zinc as an initiator. ¹H NMR analysis revealed that the carbonate content in the copolymer was almost equal to that in the feed. DSC results indicated that T_g of the copolymer increased with increasing carbonate content in the copolymer. Moreover, the protecting benzylidene groups in the copolymer poly(L ‐lactide‐co‐9‐phenyl‐2,4,8,10‐tetraoxaspiro[5,5]undecan‐3‐one) were removed by hydrogenation with palladium hydroxide on activated charcoal as a catalyst to give a functional copolymer, poly(L ‐lactide‐co‐2,2‐dihydroxylmethyl‐propylene carbonate), containing pendant primary hydroxyl groups. Complete deprotection was confirmed by ¹H NMR and FTIR spectroscopy. The in vitro degradation rate of the deprotected copolymers was faster than that of the protected copolymers in the presence of proteinase K. The cell morphology and viability on a copolymer film evaluated with ECV‐304 cells showed that poly(ester carbonate)s derived from pentaerythritol are good biocompatible materials suitable for biomedical applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45:1737 –1745, 2007     

Synthesis of arborescent styrene homopolymers and copolymers from epoxidized substrates

The synthesis of arborescent styrenic homopolymers and copolymers was achieved by anionic polymerization and grafting. Styrene and p‐(3‐butenyl)styrene were first copolymerized using sec‐butyllithium in toluene, to generate a linear copolymer with a weight‐average molecular weight M_w = 4000 and M_w/M_n = 1.05. The pendant double bonds of the copolymer were then epoxidized with m‐chloroperbenzoic acid. A comb‐branched (or arborescent generation G0) copolymer was obtained by coupling the epoxidized substrate with living styrene‐p‐(3‐butenyl)styrene copolymer chains with M_w ≈ 5000 in a toluene/tetrahydrofuran mixture. Further cycles of epoxidation and coupling reactions while maintaining M_w ≈ 5000 for the side chains yielded arborescent copolymers of generations G1–G3. A series of arborescent styrene homopolymers was also obtained by grafting M_w ≈ 5000 polystyrene side chains onto the linear and G0–G2 copolymer substrates. Size exclusion chromatography measurements showed that the graft polymers have low polydispersity indices (M_w/M_n = 1.02–1.15) and molecular weights increasing geometrically over successive generations. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of long‐chain‐branched polyethylene by ethylene homopolymerization with a novel nickel(II) α‐diimine catalyst

Long‐chain‐branched polyethylene with a broad or bimodal molecular weight distribution was synthesized by ethylene homopolymerization via a novel nickel(II) α‐diimine complex of 2,3‐bis(2‐phenylphenyl)butane diimine nickel dibromide ({[2‐C₆H₄(C₆H₅)]? N?C? (CH₃)C(CH₃)?N? [2‐C₆H₄(C₆H₅)]}NiBr₂) that possessed two stereoisomers in the presence of modified methylaluminoxane. The influences of the polymerization conditions, including the temperature and Al/Ni molar ratio, on the catalytic activity, molecular weight and molecular weight distribution, degree of branching, and branch length of polyethylene, were investigated. The resultant products were confirmed by gel permeation chromatography, gas chromatography/mass spectrometry, and ¹³C NMR characterization to be composed of higher molecular weight polyethylene with only isolated long‐branched chains (longer than six carbons) or with methyl pendant groups and oligomers of linear α‐olefins. The long‐chain‐branched polyethylene was formed mainly through the copolymerization of ethylene growing chains and macromonomers of α‐olefins. The presence of methyl pendant groups in the polyethylene main chain implied a 2,1‐insertion of the macromonomers into [Ni]? H active species. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1325–1330, 2005     

Synthesis of multihydroxyl branched polyethers by cationic copolymerization of 3,3‐bis(hydroxymethyl)oxetane and 3‐ethyl‐3‐(hydroxymethyl)oxetane

The cationic ring‐opening polymerization of 3,3‐bis(hydroxymethyl)oxetane (BHMO) and the copolymerization of BHMO with 3‐ethyl‐3‐(hydroxymethyl)oxetane (EOX) were studied. Medium molecular weight polymers (number‐average molecular weight ≈ 2 × 10³) were obtained in bulk polymerization. Poly[3,3‐bis(hydroxymethyl)oxetane], as highly insoluble, was only characterized by gel permeation chromatography and NMR methods in the esterified form. Copolymers of BHMO and EOX that were slightly soluble in organic solvents were characterized in more detail. In a copolymerization from a 1:1 mixture, the comonomers were consumed at equal rates. Matrix‐assisted laser desorption/ionization time‐of‐flight analysis confirmed that a random 1:1 copolymer was formed. ¹³C NMR analysis indicated that in contrast to previously described homopolymers of EOX in which the degree of branching was limited, the homopolymers of BHMO were highly branched. This pattern was preserved in the copolymers; EOX units were predominantly linear, whereas BHMO units were predominantly branched. The copolymerization of BHMO with EOX provides, therefore, a route to multihydroxyl branched‐polyethers with various degrees of branching containing ? OH groups exclusively as ≡C? CH₂? OH units. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1991–2002, 2002     

Photoresponsive biodegradable poly(carbonate)s with pendent o‐nitrobenzyl ester

Photoresponsive amphiphilic diblock poly(carbonate)s mPEG₁₁₃‐b‐PMNC_n with pendent o‐nitrobenzyl ester group were synthesized through ring‐opening polymerization (ROP) using 1,8‐diazabi‐cyclo[5.4.0]undec‐7‐ene (DBU) as catalyst and monomethoxy poly(ethylene glycol) (mPEG) as macroinitiator. In aqueous solution, the copolymers can self‐assemble to spherical micelles with a PC core and a PEG shell. The critical micelle concentration (CMC), size, and morphology of the micelles were demonstrated by means of fluorescence spectroscopy, transmission electron microscopes (TEM), and dynamic light scattering (DLS). Under UV light irradiation, the amphiphilic copolymer micelles disassembled because of the photocleavage of o‐NB ester, and the light‐controlled release behaviors of payload Nile red were further proved. This study provides a convenient way to construct smart poly(carbonate)s nanocarriers for controlled drug release. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2770–2780     

Synthesis of novel branched ethylene/cyclopentene copolymers with only cis‐1,3‐enchained cyclopentene units using α‐diimine nickel(II) complexes in the presence of methylaluminoxane

The copolymerization of ethylene with cyclopentene catalyzed by three α‐diimine nickel(II) complexes in the presence of methylaluminoxane (MAO) was investigated. High‐molecular‐weight branched ethylene/cyclopentene copolymers with only cis‐1,3‐enchained cyclopentene units, which has not been reported previously, were obtained. The catalytic activity, cyclopentene incorporation, copolymer molecular weight, and molecular‐weight distribution could be controlled over a wide range through the variation of the catalyst structure and polymerization conditions, including cyclopentene concentration in the feed and polymerization temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2186–2192, 2008     

Synthesis of biodegradable copolymers with low‐toxicity zirconium compounds. IV. Copolymerization of glycolide with trimethylene carbonate and 2,2‐dimethyltrimethylene carbonate: Microstructure analysis of copolymer chains by high‐resolution nuclear magnetic resonance spectroscopy

The results of the copolymerization of glycolide with cyclic trimethylene carbonate and 2,2‐dimethyltrimethylene carbonate are described. The copolymerization was conducted in the presence of low‐toxicity zirconium(IV) acetylacetonate as an initiator. With this kind of initiator, the composition of the comonomer units in the copolymer chains was assumed to be obtained with high efficiency. Despite significant differences in the comonomer reactivity, in copolymers containing comparable amounts of glycolidyl and carbonate sequences, highly randomized chain structures were observed. This effect resulted from strong intermolecular transesterification that proceeded during the studied copolymerization and caused glycolidyl microblock randomization. The assignment of the spectral NMR lines to appropriate comonomer sequences of polymeric chains was performed in the region of methylene protons of glycolidyl units in ¹H NMR spectra of the copolymers and in the carbonyl region of carbon spectra. The equations were formulated for a detailed characterization of the obtained copolymer chains, the average lengths of the blocks, and the transesterification and randomization coefficients. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 98–114, 2006     

Monte Carlo simulation of size exclusion chromatography for randomly branched and crosslinked polymers

The elution curves of size exclusion chromatography for nonlinear polymers formed through random branching and crosslinking of long polymer chains were simulated with a Monte Carlo method. We considered two types of measured molecular weight distributions (MWDs): (1) the MWD calibrated relative to standard linear polymers and (2) the MWD obtained with a light scattering (LS) photometer in which the weight‐average molecular weight of polymers within the elution volume is determined directly. The calibrated MWDs clearly underestimate the molecular weights for both randomly branched and crosslinked polymers, and this technique can be used to assess the degree of deviation from the true MWD. When the primary chains conform to the most probable distribution, the calibrated MWD can be estimated reasonably well with the Zimm–Stockmayer equation for the g factor with the help of the relationship between the average number of branch points per molecule and the degree of polymerization. However, the LS method gives good estimates of the true MWD for both randomly branched and crosslinked polymers, although the agreement is better for the branched ones. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2009–2018, 2000     

Reaction of carbon dioxide with glycidol: The synthesis of a novel hyperbranched oligomer with a carbonate main chain with a hydroxyl terminal

A novel branched polycarbonate with a hydroxyl group at the chain end was synthesized by the copolymerization of glycidol with carbon dioxide (CO₂). The copolymerization was carried out with 5 mol % of an alkali metal halide or quaternary ammonium salt as a catalyst under atmospheric CO₂. The obtained poly(glycidol‐co‐carbon dioxide) was O‐benzoylated and O‐silylated, and the corresponding polymers were analyzed with IR, size exclusion chromatography, ¹³C NMR, and ²⁹Si NMR. The IR spectroscopy analysis of the O‐benzoylated polymer revealed that the maximum incorporation degree of the carbonate group was 90% (i.e., the CO₂/glycidol composition ratio was 0.9:1.0). The incorporation of CO₂ as a carbonate unit was also confirmed by the treatment of this polymer with n‐butylamine, which caused the aminolysis of the carbonate and led to degraded products. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2506–2511, 2004     

One‐step synthesis of polycarbonates bearing pendant carboxyl groups by lipase‐catalyzed ring‐opening polymerization

The ring‐opening polymerization of a monomer containing a free carboxylic acid group is reported for the first time. The monomer, 5‐methyl‐5‐carboxyl‐1,3‐dioxan‐2‐one (MCC), was copolymerized with trimethylene carbonate (TMC) in an enzymatic ring‐opening polymerization conducted in bulk at 80 °C. The low‐melting TMC comonomer also solubilized the high‐melting MCC monomer, allowing for solvent‐free polymerizations. Six commercially available lipases were screened, and Candida antarctica lipase‐B (Novozym‐435) and Pseudomonas cepacia lipase were selected to catalyze the copolymerization because of their higher monomer conversions. Higher molecular weight polymers (weight‐average molecular weight = 7800–9200) were prepared when Novozym‐435 was used, with less MCC incorporated into the copolymer than used in the monomer feed. However, Pseudomonas cepacia lipase showed good agreement between the molar feed ratios and the molar composition, but the molecular weights (weight‐average molecular weight = 3600–4800) were lower than those obtained when Novozym‐435 was used. ¹³C NMR spectral data were used for microstructural analysis, which suggested the formation of random, linear, and pendant carboxylic acid groups containing polycarbonates with hydroxyl groups at both chain ends. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1267–1274, 2002     

Amphiphilic block and statistical copolymers with pendant glucose residues: Controlled synthesis by living cationic polymerization and the effect of copolymer architecture on their properties

Amphiphilic block and statistical copolymers of vinyl ethers (VEs) with pendant glucose residues were synthesized by the living cationic polymerization of isobutyl VE (IBVE) and a VE carrying 1,2:5,6‐di‐O‐isopropylidene‐D ‐glucose (IpGlcVE), followed by deprotection. The block copolymer was prepared by a two‐stage sequential block copolymerization, whereas the statistical copolymer was obtained by the copolymerization of a mixture of the two monomers. The monomer reactivity ratios estimated with the statistical copolymerization were r₁ (IBVE) = 1.65 and r₂ (IpGlcVE) = 1.15. The obtained statistical copolymers were nearly uniform with the comonomer composition along the main chain. Both the block and statistical copolymers had narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight ∼ 1.1). Gel permeation chromatography, static light scattering, and spin–lattice relaxation time measurements in a selective solvent revealed that the block copolymer formed multimolecular micelles, possibly with a hydrophobic poly(IBVE) core and a glucose‐carrying poly(VE) shell, whereas the statistical copolymer with nearly the same molecular weight and segment composition was molecularly dispersed in solution. The surface properties of the solvent‐cast films of the block and statistical copolymer were also investigated with the contact‐angle measurement. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 459–467, 2001     

Synthesis,characterization, and properties of poly(ester‐phosphoester)s by lanthanum triphenolate‐catalyzed ring‐opening copolymerization

The ring‐opening copolymerization of methyl ethylene phosphate (MEP, 2‐methoxy‐2‐oxo‐1,3,2‐dioxaphospholane) and ε‐caprolactone (CL) was performed in bulk with lanthanum tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)s as single‐component catalyst, resulting in poly(ester‐phosphoester) random copolymers with high molecular weight and moderate molecular weight distribution. The properties of the copolymers were characterized by differential scanning calorimetry, X‐ray diffractometer, dynamic mechanical analysis, and static water contact angle measurement. The crystallinities of the copolymers were reduced with the increase of MEP molar fraction in the products. Moreover, copolymers with enhanced hydrophilicity and lower glass transition temperature could be obtained with higher MEP content, which may provide potential applications in biomedical field. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Synthesis of a norbornene monomer having cyclic carbonate moiety based on CO2 fixation and its transition metal‐catalyzed polymerizations

A norbornene monomer bearing cyclic carbonate moiety ( NB‐CC ) was successfully synthesized from the corresponding precursor having epoxy moiety by its reaction with carbon dioxide under atmospheric pressure, which was efficiently catalyzed by lithium bromide. NB‐CC underwent the ring‐opening metathesis polymerization (ROMP) catalyzed by a ruthenium carbene complex to give the corresponding poly(norbornene), of which side chain inherited the cyclic carbonate moiety from the monomer without any deterioration. The same ROMP system was applicable to the copolymerization of NB‐CC and 5‐butyl‐2‐norbornene ( BNB ), which afforded the corresponding copolymer with a composition ratio same as a feed ratio. In addition, by using a catalytic system consisted of palladium (II) acetate/tricyclohexylphosphine/triphenylcarbenium tetrakis(pentafluorophenyl)borate, the copolymerization of NB‐CC and BNC proceeded successfully in a vinyl addition polymerization mode to give the corresponding poly(norbornene) having CC moiety in the side chain. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3896–3902, 2010     

Radical polymerization in the presence of peroxide and reducing agent monomer for branched polymers

In this article, we report the radical polymerization in the presence of peroxide and commercially available or designed reducing agent monomer (RAM) for the preparation of branched poly(methyl methacrylate)s (PMMAs). The reaction behavior of the RAM was studied by NMR. Triple‐detection SEC (TD‐SEC) analysis was used to confirm the branching structure of the prepared PMMAs and to investigate the influence of peroxide concentration and RAM concentration on molecular weight and branched structure. The obtained branched PMMAs exhibited high molecular weights and relatively narrow polydispersities at high conversion of MMA. Interestingly, a significant increase in molecular weight and degree of branching of the obtained polymers are observed in higher BPO concentration, these results are quite different from that reported in the literature. The unique radical polymerization mechanism in the RAM/BPO redox‐initiated radical polymerization system resulted in branched PMMAs with high molecular weights at relatively high RAM and BPO concentrations. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 833–840     

Molecular design of diene monomers containing an ester functional group for the synthesis of poly(diene sulfone)s by radical alternating copolymerization with sulfur dioxide

Functional poly(diene sulfone)s are prepared by the radical alternating copolymerization of 1,3‐diene monomers containing an ester substituent with sulfur dioxide. Methyl 3,5‐hexadienoate (MH) and methyl 5,7‐octadienoate (MO) with both an alkylene spacer and a terminal diene structure are suitable to produce a high‐molecular‐weight copolymer in a high yield, while the copolymerization of 5,7‐nonadienoic acid, ethyl 2,4‐pentadienoate, and ethyl 4‐methyl‐2,4‐pentadienoate including either an alkylene spacer or a terminal diene structure lead to unsuccessful results. The ¹³C NMR chemical shift values of MH and MO suggest a high electron density at their reacting α‐carbon for exhibiting a high copolymerization reactivity. Fluorene‐containing diene monomers, 9‐fluorenyl 3,5‐hexadienoate (FH) and 9‐fluorenyl 5,7‐octadienoate (FO), are also prepared and copolymerized with sulfur dioxide. The thermal and optical properties of the poly(diene sulfone)s containing the methyl and fluorenyl ester substituents in the side chain are investigated. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1000–1009