Synthesis and characterization of amphiphilic block copolymers with allyl side‐groups

The synthesis of a new cyclic carbonate monomer containing an allyl group was reported and its biodegradable amphiphilic block copolymer, poly(ethylene glycol)‐block‐poly(L ‐lactide‐co‐5‐methyl‐5‐allyloxycarbonyl‐propylene carbonate) [PEG‐b‐P(LA‐co‐MAC)] was synthesized by ring‐opening polymerization (ROP) of L ‐lactide (LA) and 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one (MAC) in the presence of poly (ethylene glycol) as a macroinitiator, with diethyl zinc as a catalyst. ¹³C NMR and ¹H NMR were used for microstructure identification of the copolymers. The copolymer could form micelles in aqueous solution. The core of the micelles is built of the hydrophobic P(LA‐co‐MAC) chains, whereas the shell is set up by the hydrophilic PEG blocks. The micelles exhibited a homogeneous spherical morphology and unimodal size distribution. By using the cyclic carbonate monomer containing allyl side‐groups, crosslinking of the PEG‐b‐P(LA‐co‐MAC) inner core was possible. The adhesion and spreading of ECV‐304 cells on the copolymer were better than that on PLA films. Therefore, this biodegradable amphiphilic block copolymer is expected to be used as a biomaterial for drug delivery and tissue engineering. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5518–5528, 2007     

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     

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     

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     

Synthesis and characterization of novel biodegradable block copolymer poly(ethylene glycol)‐block‐poly(L‐lactide‐co‐2‐methyl‐2‐carboxyl‐propylene carbonate)

An amphiphilic block copolymer, poly(ethylene glycol)‐block‐poly(L ‐lactide‐co‐2‐methyl‐2‐benzoxycarbonyl‐propylene carbonate) [PEG‐b‐P(LA‐co‐MBC)], was synthesized in bulk by the ring‐opening polymerization of L ‐lactide with 2‐methyl‐2‐benzoxycarbonyl‐propylene carbonate (MBC) in the presence of poly(ethylene glycol) as a macroinitiator with diethyl zinc as a catalyst. The subsequent catalytic hydrogenation of PEG‐b‐P(LA‐co‐MBC) with palladium hydroxide on activated charcoal (20%) as a catalyst was carried out to obtain the corresponding linear copolymer poly(ethyleneglycol)‐block‐poly(L ‐lactide‐co‐2‐methyl‐2‐carboxyl‐propylenecarbonate) [PEG‐b‐P(LA‐co‐MCC)] with pendant carboxyl groups. DSC analysis indicated that the glass‐transition temperature (T_g) of PEG‐b‐P(LA‐co‐MBC) decreased with increasing MBC content in the copolymer, and T_g of PEG‐b‐P(LA‐co‐MCC) was higher than that of the corresponding PEG‐b‐P(LA‐co‐MBC). The in vitro degradation rate of PEG‐b‐P(LA‐co‐MCC) in the presence of proteinase K was faster than that of PEG‐b‐P(LA‐co‐MBC), and the cytotoxicity of PEG‐b‐P(LA‐co‐MCC) to chondrocytes from human fetal arthrosis was lower than that of poly(L ‐lactide). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4771–4780, 2005     

Synthesis of amphiphilic copolymer brushes: Poly(ethylene oxide)‐graft‐polystyrene

A well‐defined amphiphilic copolymer brush with poly(ethylene oxide) as the main chain and polystyrene as the side chain was successfully prepared by a combination of anionic polymerization and atom transfer radical polymerization (ATRP). The glycidol was first protected by ethyl vinyl ether to form 2,3‐epoxypropyl‐1‐ethoxyethyl ether and then copolymerized with ethylene oxide by the initiation of a mixture of diphenylmethylpotassium and triethylene glycol to give the well‐defined polymer poly(ethylene oxide‐co‐2,3‐epoxypropyl‐1‐ethoxyethyl ether); the latter was hydrolyzed under acidic conditions, and then the recovered copolymer of ethylene oxide and glycidol {poly(ethylene oxide‐co‐glycidol) [poly(EO‐co‐Gly)]} with multiple pending hydroxymethyl groups was esterified with 2‐bromoisobutyryl bromide to produce the macro‐ATRP initiator [poly(EO‐co‐Gly)_(ATRP). The latter was used to initiate the polymerization of styrene to form the amphiphilic copolymer brushes. The object products and intermediates were characterized with ¹H NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, Fourier transform infrared, and size exclusion chromatography in detail. In all cases, the molecular weight distribution of the copolymer brushes was rather narrow (weight‐average molecular weight/number‐average molecular weight < 1.2), and the linear dependence of ln[M₀]/[M] (where [M₀] is the initial monomer concentration and [M] is the monomer concentration at a certain time) on time demonstrated that the styrene polymerization was well controlled. This method has universal significance for the preparation of copolymer brushes with hydrophilic poly(ethylene oxide) as the main chain. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4361–4371, 2006     

New aliphatic poly(ester‐carbonates) based on 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one

The synthesis, characterization, and ring‐opening polymerization of a new cyclic carbonate monomer containing an allyl ester moiety, 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one (MAC), was performed for the first time. MAC was synthesized in five steps in good yield beginning from the starting material, 2,2‐bis(hydroxymethyl)propionic acid. Subsequent polymerization and copolymerizations of the new cyclic carbonate with rac‐lactide (rac‐LA) and ?‐caprolactone (CL) were attempted. Rac‐LA copolymerized well with MAC, but CL copolymerizations produced insoluble products. Oligomeric macroinitiators of MAC and rac‐LA were synthesized from stannous ethoxide, and both macroinitiators were used for the controlled ring‐opening polymerization of rac‐LA. The polymerization kinetics were examined by monitoring the disappearance of the characteristic C? O ring stretch of the monomer at 1240 cm^?1 with real‐time in situ Fourier transform infrared spectroscopy. Postpolymerization oxidation reactions were conducted to epoxidize the unsaturated bonds of the MAC‐functionalized polymers. Epoxide‐containing polymers may allow further organic transformations with various nucleophiles, such as amines, alcohols, and carboxylic acids. NMR was used for microstructure identification of the polymers, and size exclusion chromatography and differential scanning calorimetry were used to characterize the new functionalized poly(ester‐carbonates). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1978–1991, 2003     

Molecular dynamics simulations of PNIPAM‐co‐PEGMA copolymer hydrophilic to hydrophobic transition in NaCl solution

Classical molecular dynamics simulations were carried out to investigate the hydrophilic to hydrophobic transition of PNIPAM‐co‐PEGMA close to its lower critical solution temperature (LCST) in 1 M NaCl solution. PNIPAM‐co‐PEGMA is a copolymer of poly(N‐isopropylacrylamide) (PNIPAM) and poly(ethylene glycol) methacrylate (PEGMA). The copolymer consists of 38 monomer units of NIPAM with two PEGMA chains attached to the PNIAPM backbone. The PNIPAM‐co‐PEGMA was observed to go through the hydrophilic?hydrophobic conformational change for simulations at temperature slightly above its LCST. Na⁺ ions were found to bind strongly and directly with amide O, even more strongly with the O atoms on PEGAMS chains, whereas Cl^? ions only exhibit weak interaction with the polymer. Significantly a novel caged stable metal‐organic complex involving a Na⁺ ion coordinated by six O atoms from the copolymer was observed after the PNIPAM‐co‐PEGMA copolymer went through conformational transition to form a hydrophobic folded structure. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

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     

Volume phase transition of methacryloyl‐L‐alanine copolymer hydrogels controlled by the terminal groups in the side chains

The volume phase transition of nonionic hydrogels was controlled with a very small amount of variation (pinpoint variation) of the side chains far from the main chain. The copolymer hydrogels poly(methacryloyl‐alanine methyl ester‐co‐methacryloyl‐alanine ethyl ester) [poly(MA‐Ala‐OMe‐co‐MA‐Ala‐OEt)] and poly(methacryloyl‐alanine alkylamide‐co‐methacryloyl‐alanine ethyl ester) [poly(MA‐Ala‐NR₂‐co‐MA‐Ala‐OEt)] were studied to investigate how pinpoint variation controls the volume phase transition. All copolymer hydrogels showed a volume phase transition from a swollen phase to a collapsed phase at a definite MA‐Ala‐OEt content at a specific temperature. The MA‐Ala‐OEt content at the midpoint of the transition linearly decreased with elevation of the temperature, and the decrease was larger for poly(MA‐Ala‐OMe‐co‐MA‐Ala‐OEt) than for poly(MA‐Ala‐NR₂‐co‐MA‐Ala‐OEt). These results suggest that the association of the side chains controlling the swelling character of the hydrogels depends on the interacting ester–ester or ester–amide groups, and the former is larger than the latter. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 56–62, 2001     

Synthesis and Characterization of Novel Aliphatic Poly(carbonate‐ester)s with Functional Pendent Groups

Summary: A novel cyclic carbonate monomer 5‐methyl‐5‐(succinimide‐N‐oxycarbonyl)‐1,3‐dioxan‐2‐one (MSTC) was prepared. The copolymers of MSTC with caprolactone (CL) were further synthesized by ring‐opening copolymerization. The copolymers with amido‐amine pendent groups were obtained by aminolysis of poly(MSTC‐co‐CL) with ethylenediamine. These copolymers were characterized by IR, ¹H NMR, ¹³C NMR spectroscopies and GPC. The hydrophilicity and degradability of the copolymers with amido‐amine pendent groups were greatly improved in comparison with the PCL homopolymer.

Hydrophilicity of PCL (1), poly(MATC‐co‐CL) (16.5:83.5) (2), and poly(MATC‐co‐CL) (29.5:70.5) (3).     

Synthesis and functionalities of poly(N‐vinylalkylamide). XII. Synthesis and thermosensitive property of poly(vinylamine) copolymer prepared from poly(N‐vinylformamide‐co‐N‐vinylisobutyramide)

The differences in the polymerization abilities of N‐vinylformamide (NVF) and N‐vinylisobutyramide (NVIBA) and the synthesis of their copolymers were studied. The polymerization abilities were fairly good and quite similar to those of N‐vinyl‐ acetamide (NVA), a monomer in the same class as N‐vinylalkylamides. Since the monomer reactivity ratios were r₁ = 1.08 and r₂ = 0.92 (M₁ = NVF, M₂ = NVIBA), respectively, it is clear that the comonomers definitely were converted to random copolymers. The resulting copolymers poly(NVF‐co‐NVIBA) exhibited the cloud points sharply. The light transmittance profiles were the same as those for poly(NVIBA) although they increased from 39 °C for poly(NVIBA), with an increase in the corresponding hydrophilic NVF component. Our final objective was to produce a cloud point controlled polymer material with primary amino groups. To achieve this, we examined the hydrolysis of poly(NVF), poly(NVA), poly(NVIBA), and poly(NVF‐co‐NVIBA) to obtain poly(vinylamine) [poly(VAm)]. The hydrolytic cleavage of poly(NVF) and poly(NVA) was promoted by an increase in temperature. However, poly(NVIBA) was not cleaved appreciably. The hydrolysis of poly(NVF‐co‐NVIBA) was done under controlled conditions, and amino groups selectively were introduced to only one of two components of the copolymer. The cloud point of the hydrolyzed copolymer shifted to a higher temperature than that of the copolymer. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3674–3681, 2000     

Synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] by incorporation of carbon dioxide into epoxide polymer and the miscibility behavior of its blends with poly(methyl methacrylate) or poly(vinyl chloride)

This study was related to the investigation of the chemical fixation of carbon dioxide to a copolymer bearing epoxide and the application of the cyclic carbonate group containing copolymer‐to‐polymer blends. In the synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] [poly(DOMA‐co‐EA)] from poly(glycidyl methacrylate‐co‐ethyl acrylate) [poly(GMA‐co‐EA)] and CO₂, quaternary ammonium salts showed good catalytic activity. The films of poly(DOMA‐co‐EA) with poly(methyl methacrylate) (PMMA) or poly(vinyl chloride) (PVC) blends were cast from N,N′‐dimethylformamide solution. The miscibility of the blends of poly(DOMA‐co‐EA) with PMMA or PVC have been investigated both by DSC and visual inspection of the blends. The optical clarity test and DSC analysis showed that poly(DOMA‐co‐EA) containing blends were miscible over the whole composition range. The miscibility behaviors were discussed in terms of Fourier transform infrared spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1472–1480, 2001     

Sugars‐grafted aliphatic biodegradable poly(L‐lactide‐co‐carbonate)s by click reaction and their specific interaction with lectin molecules

A novel biodegradable aliphatic poly(L ‐lactide‐co‐carbonate) bearing pendant acetylene groups was successfully prepared by ring‐opening copolymerization of L ‐lactide (LA) with 5‐methyl‐5‐propargyloxycarbonyl‐1,3‐dioxan‐2‐one (PC) in the presence of benzyl alcohol as initiator with ZnEt₂ as catalyst in bulk at 100 °C and subsequently used for grafting 2‐azidoethyl β‐D ‐glucopyranoside and 2‐azidoethyl β‐lactoside by the typical “click reaction,” that is Cu(I)‐catalyzed cycloaddition of azide and alkyne. The density of acetylene groups in the copolymer can be tailored by the molar ratio of PC to LA during the copolymerization. The aliphatic copolymers grafted with sugars showed low cytotoxicity to L929 cells, improved hydrophilic properties and specific recognition and binding ability with lectins, that is Concanavalin A (Con A) and Ricinus communis agglutinin (RCA). Therefore, this kind of sugar‐grafted copolymer could be a good candidate in variety of biomedical applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3204 –3217, 2007     

Synthesis and characterization of novel poly(ester‐carbonate)s by copolymerization of trans‐4‐hydroxy‐L‐proline with cyclic carbonate

The melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L‐proline (N‐CBz‐Hpr) with cyclic carbonate [trimethylene carbonate (tri‐MC) or tetramethylene carbonate (tetra‐MC)] at a wide range of molar fractions in the feed produced new degradable poly(ester‐carbonate)s. The influence of reaction conditions such as polymerization time and temperature on the yield and inherent viscosity of the copolymers was investigated. The polymerizations were carried out in bulk at 140 °C with 1.5 wt % stannous octoate as a catalyst for 30 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR, differential scanning calorimetry, gel permeation chromatography, and Ubbelohde viscometry. The copolymers synthesized exhibited moderate molecular weights with rather narrow molecular weight distributions. The values of the glass‐transition temperature (T_g) of the copolymers depend on the molar fractions of cyclic carbonate. For the poly(N‐CBz‐Hpr‐co‐tri‐MC) system, with a decreased tri‐MC content from 93 to 16 mol %, the T_g increased from ?10 to 60 °C. Similarly, for the poly(N‐CBz‐Hpr‐co‐tetra‐MC) system, when the tetra‐MC content decreased from 80 to 8 mol %, the T_g increased from ?18 to 52 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐tri‐MC) T_g and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐tri‐MC)s was evaluated from weight‐loss measurements. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1435–1443, 2003     

Bio‐based copolymers obtained through miniemulsion copolymerization of methyl esters of acrylated fatty acids and styrene

Polymers based on renewable sources are promising materials, and can find many uses in coatings and adhesive applications. The goal of this work was to synthesize and characterize bio‐based styrene/acrylated fatty acid methyl ester (AFAME) copolymer—poly(styrene‐co‐AFAME) prepared by miniemulsion polymerization. The main strategy adopted was to functionalize the bio‐monomer with acrylic acid that was confirmed by ¹H NMR and FTIR measurements, to allow its free‐radical homo‐ or copolymerization with styrene. Poly(styrene‐co‐AFAME) with different AFAME content were obtained and their composition were evaluated by ¹H NMR. Dynamic light scattering measurements throughout the reactions have indicated a very stable colloidal systems and average particles size ranges 100–150 nm. The structural and physical properties of poly(styrene‐co‐AFAME) were investigated by DTG‐DTA, DSC which displayed a decreasing of glass transition temperature with increase of AFAME content. The results showed in this study have indicated that the poly(styrene‐co‐AFAME) can be used in several fields because their characteristics are totally distinct. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1422–1432     

Synthesis of gradient copolymers with complexing groups by RAFT polymerization and their solubility in supercritical CO2

We report the synthesis of new gradient fluorinated copolymers with complexing groups and soluble in supercritical carbon dioxide (scCO₂). Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate‐co‐acetoacetoxyethyl methacrylate) (poly(FDA‐co‐AAEM)) and poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate‐co‐vinylbenzylphosphonic acid diethylester) (poly(FDA‐co‐VBPDE)) gradient copolymers were synthesized by reversible addition fragmentation chain transfer polymerization in α,α,α‐trifluorotoluene. Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate‐co‐vinylbenzylphosphonic diacid) (poly(FDA‐co‐VBPDA)) gradient copolymer was efficiently obtained by cleavage of the phosphonic ester groups of poly(FDA‐co‐VBPDE). The cloud points of these gradient copolymers in dense CO₂ were measured in a variable volume view cell at temperatures between 25 and 65 °C. The gradient copolymers show very good solubility in compressed CO₂ with the decreasing order: poly(FDA‐co‐AAEM) ≈ poly(FDA‐co‐VBPDE) > poly(FDA‐co‐VBPDA). Following a green chemistry strategy, poly(FDA‐co‐AAEM) gradient copolymer was successfully synthesized in scCO₂ with a good control over number‐average molecular weight and composition. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5448–5460, 2009     

Preparation of novel poly(ethylene oxide‐co‐glycidol)‐graft‐poly(ε‐caprolactone) copolymers and inclusion complexation of the grafted chains with α‐cyclodextrin

A well‐defined comblike copolymer of poly(ethylene oxide‐co‐glycidol) [(poly(EO‐co‐Gly)] as the main chain and poly(ε‐caprolactone) (PCL) as the side chain was successfully prepared by the combination of anionic polymerization and ring‐opening polymerization. The glycidol was protected by ethyl vinyl ether to form 2,3‐epoxypropyl‐1‐ethoxyethyl ether (EPEE) first, and then ethylene oxide was copolymerized with EPEE by an anionic mechanism. The EPEE segments of the copolymer were deprotected by formic acid, and the glycidol segments of the copolymers were recovered after saponification. Poly(EO‐co‐Gly) with multihydroxyls was used further to initiate the ring‐opening polymerization of ε‐caprolactone in the presence of stannous octoate. When the grafted copolymer was mixed with α‐cyclodextrin, crystalline inclusion complexes (ICs) were formed, and the intermediate and final products, poly(ethylene oxide‐co‐glycidol)‐graft‐poly(ε‐caprolactone) and ICs, were characterized with gel permeation chromatography, NMR, differential scanning calorimetry, X‐ray diffraction, and thermogravimetric analysis in detail. The obtained ICs had a channel‐type crystalline structure, and the ratio of ε‐caprolactone units to α‐cyclodextrin for the ICs was higher than 1:1. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3684–3691, 2006     

Novel,biodegradable, functional poly(ester‐carbonate)s by copolymerization of trans‐4‐hydroxy‐L‐proline with cyclic carbonate bearing a pendent carboxylic group

Water‐soluble poly(ester‐carbonate) having pendent amino and carboxylic groups on the main‐chain carbon is reported for the first time. This article describes the melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) with 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) at a wide range of molar fractions. The influence of reaction conditions such as catalyst concentration, polymerization time, and temperature on the number average molecular weight (M_n) and molecular weight distribution (M_w/M_n) of the copolymers was investigated. The polymerizations were carried out in bulk at 110 °C with 3 wt % stannous octoate as a catalyst for 16 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR, differential scanning calorimetry, and gel permeation chromatography. The copolymers synthesized exhibited moderate molecular weights (M_n = 6000–14,700 g mol^?1) with reasonable molecular weight distributions (M_w/M_n = 1.11–2.23). The values of the glass‐transition temperature (T_g) of the copolymers depended on the molar fractions of cyclic carbonate. When the MBC content decreased from 76 to 12 mol %, the T_g increased from 16 to 48 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐MBC) T_g and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐MBC)s was evaluated from weight‐loss measurements and the change of M_n and M_w/M_n. Debenzylation of 3 by catalytic hydrogenation led to the corresponding linear poly(ester‐carbonate), 4 , with pendent amino and carboxylic groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2303–2312, 2004     

Lactic acid‐ and carbonate‐based crosslinked polymeric micelles for drug delivery

Our objective was to synthesize and evaluate lactic acid‐ and carbonate‐based biodegradable core‐ and core‐corona crosslinkable copolymers for anticancer drug delivery. Methoxy poly(ethylene glycol)‐b‐poly(carbonate‐co‐lactide‐co‐5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxane‐2‐one) [mPEG‐b‐P(CB‐co‐LA‐co‐MAC)] and methoxy poly(ethylene glycol)‐b‐poly(acryloyl carbonate)‐b‐poly(carbonate‐co‐lactide) [mPEG‐b‐PMAC‐b‐P(CB‐co‐LA)] copolymers were synthesized by ring‐opening polymerization of LA, CB, and MAC using mPEG as an macroinitiator and 1,8‐diazabicycloundec‐7‐ene as a catalyst. These amphiphilic copolymers which exhibited low polydispersity and critical micelle concentration values (0.8–1 mg/L) were used to prepare micelles with or without drug and stabilized by crosslinking via radical polymerization of double bonds introduced in the core and interface to improve stability. mPEG₁₁₄‐b‐P(CB₈‐co‐LA₃₅‐co‐MAC_2.5) had a higher drug encapsulation efficiency (78.72% ± 0.15%) compared to mPEG₁₁₄‐b‐PMAC_2.5‐b‐P(CB₉‐co‐LA₃₉) (20.29% ± 0.11%).¹H NMR and IR spectroscopy confirmed successful crosslinking (～70%) while light scattering and transmission electron microscopy were used to determine micelle size and morphology. Crosslinked micelles demonstrated enhanced stability against extensive dilution with aqueous solvents and in the presence of physiological simulating serum concentration. Furthermore, bicalutamide‐loaded crosslinked micelles were more potent compared to non‐crosslinked micelles in inhibiting LNCaP cell proliferation irrespective of polymer type. Finally, these results suggest crosslinked micelles to be promising drug delivery vehicles for chemotherapy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013