Functionalization of polymeric organolithium compounds with formaldehyde

Functionalizations of poly(styryl)lithium (PSLi), poly(butadienyl)lithium (PBDLi), and poly(isoprenyl)lithium (PILi) with formaldehyde were investigated in benzene solutions at room temperature. Dimer and unfunctionalized products, in addition to the expected products, were found in the PSLi functionalization with formaldehyde. The byproducts were analyzed by ¹H NMR, ¹³C NMR, size exclusion chromatography (SEC), and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and showed evidence for Cannizzaro reactions and electron‐transfer reactions. A molecular weight dependence of the dimer formation was found for PSLi functionalizations for number‐average molecular weights of less than 20,000; the dimer formation decreased as the molecular weight increased. Changing the reaction conditions did not eliminate dimer formation in the PSLi functionalization. The reactions of PBDLi and PILi with formaldehyde effected quantitative functionalizations, as determined by SEC, ¹H NMR, ¹³C NMR, MALDI‐TOF MS, quantitative column chromatography, and end‐group titration. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2435–2453, 2003     

One‐pot inimer promoted ROCP synthesis of branched copolyesters using α‐hydroxy‐γ‐butyrolactone as the branching reagent

An array of branched poly(?‐caprolactone)s was successfully synthesized using an one‐pot inimer promoted ring‐opening multibranching copolymerization (ROCP) reaction. The biorenewable, commercially available yet unexploited comonomer and initiator 2‐hydroxy‐γ‐butyrolactone was chosen as the inimer to extend the use of 5‐membered lactones to branched structures and simultaneously avoiding the typical tedious work involved in the inimer preparation. Reactions were carried out both in bulk and in solution using stannous octoate (Sn(Oct)₂) as the catalyst. Polymerizations with inimer equivalents varying from 0.01 to 0.2 were conducted which resulted in polymers with a degree of branching ranging from 0.049 to 0.124. Detailed ROCP kinetics of different inimer systems were compared to illustrate the branch formation mechanism. The resulting polymer structures were confirmed by ¹H, ¹³C, and ₁H‐₁₃C HSQC NMR and SEC (RI detector and triple detectors). The thermal properties of polymers with different degree of branching were investigated by DSC, confirming the branch formation. Through this work, we have extended the current use of the non‐homopolymerizable γ‐butyrolactone to the branched polymers and thoroughly examined its behaviors in ROCP. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1908–1918     

Orthogonally functionalizable copolymers based on a novel reactive carbonate monomer

A novel N‐hydroxy succinimide‐based carbonate monomer that allows direct synthesis of polymers incorporating a reactive carbonate group in the side chain was synthesized. This new monomer was copolymerized with methyl methacrylate and poly(ethylene glycol) methylether methacrylate using free‐radical polymerization to obtain organo‐ and water‐soluble reactive copolymers. Copolymerization of the activated carbonate monomer with an azide‐containing monomer and N‐hydroxy succinimide‐containing activated ester monomer provided orthogonally functionalizable copolymers. The pendant reactive carbonate groups of the copolymers were functionalized with amines to obtain carbamates. Polymers capable of orthogonal functionalization could be selectively functionalized as desired using subsequent 1,3‐dipolar cycloaddition or amidation reactions. The novel monomer and the copolymers were characterized by ¹H‐NMR, ¹³C‐NMR, and infrared spectroscopy. The efficient stepwise orthogonal functionalization of the copolymers were examined via ¹H‐NMR spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Functionalization of polymeric organolithium compounds with 3,4‐epoxy‐1‐butene: Precursors for diene‐functionalized macromonomers

The functionalization of polymeric organolithiums (PLi) with 3,4‐epoxy‐1‐butene (EPB) in a hydrocarbon solution yielded the corresponding hydroxybutene‐functionalized polymers in high yields (>95%). Three modes of addition of PLi to EPB were observed (1,4, 3,4, and 4,3). The products and chain‐end structures were characterized by ¹H NMR, ¹³C NMR, attached‐proton‐test ¹³C NMR, calculated ¹³C NMR chemical shifts, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). The regioselectivity of the addition depended on the PLi chain‐end structure, the reaction conditions, and the addition of lithium salts or Lewis bases. In the absence of additives, the functionalization of poly(styryl)lithium (PSli) produced equal amounts of 1,4‐, 3,4‐, and 4,3‐addition, as determined by quantitative ¹³C NMR analysis. The use of a low temperature (6 °C), inverse addition, the addition of triethylamine (TEA; [TEA]/[PSLi] = 20) as a Lewis base, or dienyllithium chain ends produced polymers with only the 1,4‐addition product. Mild dehydration of the hydroxybutene‐functionalized polymer with p‐toluenesulfonic acid produced the corresponding diene‐functionalized macromonomer, as shown by MALDI‐TOF MS. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 947–957, 2003     

Butadiene–isoprene copolymerization with V(acac)3‐MAO. Crystalline and amorphous trans‐1,4 copolymers

Butadiene‐isoprene copolymerization with the system V(acac)₃‐MAO was examined. Crystalline or amorphous copolymers were obtained depending on isoprene content. Both butadiene and isoprene units exhibit a trans‐1,4 structure and are statistically distributed along the polymer chain. Polymer microstructure, comonomer composition, and distribution along the polymer chain were determined by ¹³C and ¹H NMR analysis. The thermal and X‐ray behaviors of the copolymers were also investigated and compared with results from solid‐state ¹³C NMR experiments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4635–4646, 2007     

Crosslinked poly(ester anhydride)s based on poly(ε‐caprolactone) and polylactide oligomers

Resorbable poly(ester anhydride) networks based on ε‐caprolactone, L ‐lactide, and D,L ‐lactide oligomers were synthesized. The ring‐opening polymerization of the monomers yielded hydroxyl telechelic oligomers, which were end‐functionalized with succinic anhydride and reacted with methacrylic anhydride to yield dimethacrylated oligomers containing anhydride bonds. The degree of substitution, determined by ¹³C NMR, was over 85% for acid functionalization and over 90% for methacrylation. The crosslinking of the oligomers was carried out thermally with dibenzoyl peroxide at 120 °C, leading to polymer networks with glass‐transition temperatures about 10 °C higher than those of the constituent oligomers. In vitro degradation tests, in a phosphate buffer solution (pH 7.0) at 37 °C, revealed a rapid degradation of the networks. Crosslinked polymers based on lactides exhibited high water absorption and complete mass loss in 4 days. In ε‐caprolactone‐based networks, the length of the constituent oligomer determined the degradation: PCL5‐AH, formed from longer poly(ε‐caprolactone) (PCL) blocks, lost only 40% of its mass in 2 weeks, whereas PCL10‐AH, composed of shorter PCL blocks, completely degraded in 2 days. The degradation of PCL10‐AH showed characteristics of surface erosion, as the dimensions of the specimens decreased steadily and, according to Fourier transform infrared, labile anhydride bonds were still present after 90% mass loss. © 2003 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3788–3797, 2003     

Determination of methylene bridge crosslinking in chloromethylated PS‐DVB resins

We present the development of a method for the determination of methylene bridge crosslinking in ¹³C‐labeled chloromethylated polystyrene‐divinylbenzene resins. Our system uses a new room temperature reduction of the chloromethyl groups that circumvents the possible challenges associated with additional crosslinking. We demonstrate how the reduction of the chloromethyl groups allowed for the determination of methylene bridging, derived from the methylenebis(ethenylbenzene) crosslinker, based on the integration of the methylene signal in the ¹³C NMR spectra. Utilizing this method, the total crosslinking within the chloromethylated resin generated at 35 °C was determined to be upward of 10 wt %, which increased from 6 wt % in the unfunctionalized resin. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1955–1960     

Modified soybean oil as a reactive diluent: Synthesis and characterization

Soybean oil was modified in two steps: (1) conjugation of soybean oil and (2) Diels‐Alder addition with 3‐(trimethoxysilyl)propyl methacrylate, 2,2,2‐trifluoroethyl methacrylate and triallyl ether acrylate. The structures were characterized using ¹H NMR, ¹³C NMR, ¹³C‐¹H gradient heteronuclear single quantum coherence (gHSQC) NMR spectroscopy, and MALDI‐TOF mass spectrometry. The ¹³C‐¹H gHSQC NMR spectra helped confirm the formation of a cyclohexene ring in all reactions, indicating a Diels‐Alder addition. The diluent efficiency of modified soybean oil was evaluated in long oil alkyd formulation. Triallyl ether functionalized soybean oil resulted in the highest reduction in the viscosity of the alkyd formulations. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3045–3059     

Calcium‐containing poly(urethane‐urea)s: Synthesis,spectral, and thermal studies

A calcium salt of mono(hydroxypentyl)phthalate [Ca(HPP)₂] was synthesized by the reaction of 1,5‐pentanediol, phthalic anhydride, and calcium acetate. Four different bisureas such as hexamethylene bis(ω,N‐hydroxyethylurea), tolylene 2,4‐bis(ω,N‐hydroxyethylurea), hexamethylene bis(ω,N‐hydroxypropylurea), and tolylene 2,4‐bis(ω,N‐hydroxypropylurea) were prepared by reacting ethanolamine or propanolamine with hexamethylene diisocyanate (HMDI) or tolylene 2,4‐diisocyanate (TDI). Calcium‐containing poly(urethane‐urea)s (PUUs) were synthesized by reacting HMDI or TDI with 1:1 mixtures of Ca(HPP)₂ and each of the bisureas with di‐n‐butyltin dilaurate as a catalyst. The PUUs were well characterized by Fourier transform infrared spectroscopy, ¹H and ¹³C NMR, solid‐state ¹³C–cross‐polarization/magic‐angle spinning NMR, viscosity, solubility, elemental analysis, and X‐ray diffraction studies. Thermal properties of the polymers were also examined with thermogravimetric analyses and differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1809–1819, 2004     

Photoactive,liquid‐crystalline,hyperbranched benzylidene polyesters: Synthesis and characterization

A novel photoactive, liquid‐crystalline, hyperbranched benzylidene polyester (PAHBP) was synthesized from a dilute solution of an A₂ photoactive monomer [bis(4‐hydroxybenzylidene)‐4‐phenyl cyclohexanone] and a B₃ monomer (1,3,5‐benzene tricarboxylic acid chloride) by the solution polycondensation method in the presence of pyridine as a condensing agent. PAHBP was thoroughly characterized by Fourier transform infrared, ¹H and ¹³C NMR, ultraviolet–visible spectrometry, and gel permeation chromatography. The inherent viscosity of the polymer was 0.35 dL/g in tetrahydrofuran. The degree of branching was 0.53, which confirmed the branched architecture of the polymer. Furthermore, thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy were used to examine the thermal stability and thermotropic liquid‐crystalline properties of the hyperbranched polyester. The polymer exhibited a nematic mesophase over a wide range of temperatures. The photoreactivity of PAHBP was studied by photolysis under ultraviolet light. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 53–61, 2006     

Preparation and characterization of biodegradable poly(trimethylenecarbonate‐ε‐caprolactone)‐block‐poly(p‐dioxanone) copolymers

A series of poly(trimethylenecarbonate‐ε‐caprolactone)‐block‐poly(p‐dioxanone) copolymers were prepared with varying feed rations by using two step polymerization reactions. Poly(trimethylenecarbonate)(ε‐caprolactone) random copolymer was synthesized with stannous‐2‐ethylhexanoate and followed by adding p‐dioxanone monomer as the other block. The ring opening polymerization was carried out at high temperature and long reaction time to get high molecular weight polymers. The monofilament fibers were obtained using conventional melting spun methods. The copolymers were identified by ¹H and ¹³C NMR spectroscopy and gel permeation chromatography (GPC). The physicochemical properties, such as viscosity, molecular weight, melting point, glass transition temperature, and crystallinity, were studied. The hydrolytic degradation of copolymers was studied in a phosphate buffer solution, pH = 7.2, 37 °C, and a biological absorbable test was performed in rats. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2790–2799, 2005     

s‐Triazine‐based hyperbranched polyethers: Synthesis,characterization, and properties

A series of s‐triazine‐based hyperbranched polyethers (HBPE) have been synthesized to obtain thermostability but flexible polymers by an interfacial polycondensation of different diols as A₂ and cyanuric chloride as B₃ monomers using A₂ + B₃ approach in the presence of a phase transfer catalyst. The polymerization reaction parameters are optimized, and the results indicate that the optimum conditions for the interfacial polycondensation are a 2:3 mole ratio of cyanuric chloride to diol using butanediol, benzyldimethylhexadecyl ammonium chloride as the catalyst, dichloromethane as the organic solvent, and a three‐step procedure with keeping the reaction mixture at different low temperatures for 2h/2h/5h. Other techniques such as high‐temperature solution, one‐step polycondensation, and transesterification were also carried out to synthesize the HBPE but proved to be not suitable due to large number of side reactions. The synthesized polymers were characterized by FTIR, ¹H NMR, and ¹³C NMR spectroscopy, hydroxyl number determination, solution viscosity measurements, and GPC analysis. The thermal behavior of the hyperbranched polymer was investigated by thermogravimetric analysis and differential scanning calorimetry. All the results were compared with those from an analogous linear polyether, obtained from 2‐methoxy‐4,6‐dichloro‐s‐triazine and butanediol by using the same polymerization technique. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3994–4004, 2010     

Synthesis and hydrolytic degradation of a random copolymer derived from 1,4‐dioxan‐2‐one and glycolide

Novel biodegradable copolymers, poly(1,4‐dioxan‐2‐one‐co‐glycolide) [P(DON‐co‐GA)] containing a high proportion of 1,4‐dioxan‐2‐one (DON), were synthesized by copolymerizations of DON and glycolide (GA) at 120 °C for 16 h using stannous octoate as catalyst. Chemical composition and microstructural variation of the resulting copolymer were investigated by ¹H‐ and ¹³C NMR and thermal properties by differential scanning calorimetry (DSC). From the ¹³C NMR spectra, it was observed that, apart from the expected preponderance of DON sequences, the minor component, GA, was indeed distributed at various points along the copolymer chain rather than incorporated as distinct blocks, which is consistent with a random sequence distribution. This view also was supported by the DSC results, which showed that most copolymers were amorphous except for one with a relatively high fraction of DON. The conclusion that it was a random structure rather than a statistical copolymer is discussed, using the theories about the mechanism of this type of polymerization in current as a reference. P(DON‐co‐GA) films were prepared by casting the copolymer solution in hexafluoroisopropanol (HFIP) with two concentrations of the polymeric solution (10 and 25 wt %). The in vitro hydrolytic degradation behaviors of these films were studied in phosphate buffer solution (pH = 7.4) at 37 °C and characterized by DSC, scanning electron microscopy, weight loss, and change in inherent viscosity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2558–2566, 2004     

Dendronized polymers via Diels–Alder “click” reaction

A modular approach toward the synthesis of polymers containing dendron groups as side chains is developed using the Diels–Alder “click” reaction. For this purpose, a styrene‐based polymer appended with anthracene groups as reactive side chains was synthesized. First through third‐generation polyester dendrons containing furan‐protected maleimide groups at their focal point were synthesized. Facile, reagent‐free, thermal Diels–Alder cycloaddition between the anthracene‐containing polymer and latent‐reactive dendrons leads to quantitative functionalization of the polymer chains to afford dendronized polymers. The efficiency of this functionalization step was monitored using ¹H and ¹³C NMR spectroscopy and FTIR and UV–vis spectrometry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 410–416, 2010     

Substituent effect on azobenzene‐based liquid‐crystalline organophosphorus polymers

An Erratum has been published for this article in Journal of Polymer Science Part A: Polymer Chemistry (2003) 41(23) 3862 A new series of combined‐type, azobenzene‐based organophosphorus liquid‐crystalline polymers were synthesized, and their photoisomerization properties were studied. The prepared polymers contained azobenzene units as both the main‐chain and side‐chain mesogens. Various groups were substituted in the terminal of the side‐chain azobenzene mesogen, and the effects of the substituents were investigated. All the polymers were prepared at the ambient temperature by solution polycondensation with various 4‐substituted phenylazo‐4′‐phenyloxyhexylphosphorodichloridates and 4,4′‐bis(6‐hydroxyhexyloxy) azobenzene. The polymers were characterized with gel permeation chromatography, Fourier transform infrared, and ¹H, ¹³C, and ³¹P NMR spectroscopy. Thermogravimetric analysis revealed that all the polymers had high char yields. The liquid‐crystalline behavior of the polymers was examined with hot‐stage optical polarizing microscopy, and all the polymers showed liquid‐crystalline properties. The formation of a mesophase was confirmed by differential scanning calorimetry (DSC). The DSC data suggested that mesophase stability was better for electron‐withdrawing substituents than for halogens and unsubstituted ones. Ultraviolet irradiation studies indicated that the time taken for the completion of photoisomerization depended on the dipolar moment, size, and donor–acceptor characteristics of the terminal substituents. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3188–3196, 2003     

Acid chloride‐functionalized hyperbranched polyester for facile and quantitative chain‐end modification: One‐pot synthesis and structure characterization

Carboxylic acid chloride end‐functionalized all‐aromatic hyperbranched polyesters were prepared from the bulk polycondensation of the AB₂ monomer 5‐(trimethylsiloxy)isophthaloyl dichloride. The acid chloride end functionality of the hyperbranched polyester was modified in situ with methanol and yielded methyl ester ends in a one‐pot process. Chain‐end functionalization and esterification were quantitative according to both potentiometric titration and ¹H NMR analysis. The signals of ¹H and ¹³C NMR spectra of the esterified hyperbranched polyester were fully assigned from model compounds of the focal, linear, dendritic, and terminal units. The degree of branching and molecular weight averages measured by ¹H and ¹³C NMR spectroscopy and multidetector size exclusion chromatography increased systematically with increasing polymerization temperatures between 80 and 200 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2855–2867, 2002     

Combinatorial functionalization with bisurea‐peptides and antifouling bisurea additives of a supramolecular elastomeric biomaterial

The bioactive additive toolbox to functionalize supramolecular elastomeric materials expands rapidly. Here we have set an explorative step toward screening of complex combinatorial functionalization with antifouling and three peptide‐containing additives in a bisurea‐based supramolecular system. Thorough investigation of surface properties of thin films with contact angle measurements, X‐ray photoelectron spectroscopy and atomic force microscopy, was correlated to cell‐adhesion of endothelial and smooth muscle cells to apprehend their respective predictive values for functional biomaterial development. Peptides were presented at the surface alone, and in combinatorial functionalization with the oligo(ethylene glycol)‐based non‐cell adhesive additive. The bisurea‐RGD additive was cell‐adhesive in all conditions, whereas the endothelial cell‐specific bisurea‐REDV showed limited bioactive properties in all chemical nano‐environments. Also, aspecific functionality was observed for a bisurea‐SDF1α peptide. These results emphasize that special care should be taken in changing the chemical nano‐environment with peptide functionalization. © 2019 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1725–1735     

Prepolymerization and postpolymerization functionalization approaches to fluorescent conjugated carbazole‐based glycopolymers via “click chemistry”

Facile prepolymerization and postpolymerization functionalization approaches to prepare well‐defined fluorescent conjugated glycopolymers through Cu(I)‐catalyzed azide/alkyne “Click” ligation were explored. Two well‐defined carbazole‐based fluorescent conjugated glycopolymers were readily synthesized based on these strategies and characterized by ¹H NMR, ¹³C NMR, IR spectra, and UV‐vis spectra. The “Click” ligation offers a very effective conjugation method to covalently attach carbohydrate residues to fluorescent conjugated polymers. In addition, the studies of carbohydrate–lectin interactions were performed by titration of concanavalin A (Con A) to D ‐glucose‐bearing poly(anthracene‐alt‐carbazole) copolymer P‐2 resulting in significant fluorescence quenching of the polymer due to carbohydrate–lectin interactions. When peanut agglutinin (PNA) was added, no distinct change in the fluorescent properties of P‐2 was observed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2948–2957, 2009     

Specific lectin interactions and temperature‐induced reversible gels in novel water‐soluble glycopolymers bearing maltotrionolactone pendant groups

Glycopolymers based on the incorporation of a diaminobutylmaltotrionolactone onto activated ethylene‐vinyl alcohol, EVOH, copolymers with distinct composition in the former counit have been prepared. Previous transformation of initial hydroxyl EVOH groups to other more reactive functional groups has been required. The activation has been performed in this current investigation by functionalization with either 4‐nitrophenyl carbonate or o‐phthalic acid groups. The structure of the resulting novel water‐soluble glycopolymers has been confirmed by FTIR, ¹H and ¹³C‐NMR spectroscopies. In addition, the glass transition temperatures and thermal stability as well as the viscoelastic behavior in bulk and in water solution have been examined as a function of chemical linkage nature. The rheological evaluation confirms the reversible gel formation in all the cases. Finally, their affinity to Concanavalin A lectin has been also analyzed proving the feasible use of these glycopolymers as molecular recognition materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 719–729, 2010     

Photoswitchable architectural polymer: Toward azo‐based polyamidoamine side‐chain dendritic polyester

A versatile approach to the synthesis of novel polyamidoamine (PAMAM) side‐chain dendritic polyester (SCDPE) possessing azobenzene motifs in the polymeric core is described and displayed reversible cis–trans (E/Z) isomerization upon exposure to UV light. A polymerization reaction was conducted in solution using ester‐terminated PAMAM dendritic diol ( 1a , G 3.5) and azobenzene dicarboxylic acid chloride in the presence of triethylamine. PAMAM dendritic diol 1a as well as SCDPE ( 1 ) were thoroughly characterized by means of IR and NMR (¹H and ¹³C) spectroscopies. The intrinsic viscosity of 1 at 36 °C in CHCl₃ was found to be 0.38 dl/g. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4182–4188, 2001