Water soluble poly(ethylene oxide) functionalized norbornene polymers

The synthesis of three different poly(ethylene oxide) macromonomers with a norbornene and oxanorbornene end group is presented. The macromonomers were polymerized to comb‐polymers by ring‐opening metathesis polymerization (ROMP) using Grubbs' Catalyst G3 to produce water soluble polymers with polydispersities between 1.04 and 1.30 and molecular weights between 14,000 and 50,000 g/mol. Characterization by static and dynamic light scattering reveals that the comb‐polymers with norbornene backbone are molecularly disperse in aqueous solution, while the oxanorbornene‐backbone polymers form small water‐soluble aggregates. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2640–2648, 2008     

Synthesis and characterization of novel alternating fluorinated copolymers bearing oligo(ethylene oxide) side chains

The synthesis and characterization of novel poly(CTFE‐g‐oligoEO) graft copolymers [chlorotrifluoroethylene (CTFE) and ethylene oxide (EO)] are presented. First, vinyl ether monomers bearing oligo(EO) were prepared by transetherification of ω‐hydroxyoligo(EO) with ethyl vinyl ether catalyzed by a palladium complex in 70–84% yields. Two vinyl ethers of different molecular weights (three and 10 EO units) were thus obtained. Then, radical copolymerization of the above vinyl ethers with CTFE led to alternating poly(CTFE‐alt‐VE) copolymers that bore oligo(OE) side chains in satisfactory yields (65%). These original poly(CTFE‐g‐oligoEO) graft copolymers were characterized by ¹H, ¹⁹F, and ¹³C NMR spectroscopy. Their molecular weights reached 19,000 g mol^?1, and their thermal properties were investigated while their glass transition temperatures ranged between ?42 and ?36 °C. Their thermogravimetric analyses under air showed decomposition temperatures of 270 °C with 10% weight loss (T_d,10%). These novel copolymers are of potential interest as polymer electrolytes in lithium ion batteries, showing room temperature conductivities ranging from 4.49 × 10^?7 to 1.45 × 10^?6 S cm^?1 for unplasticized material. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Amphiphilic Block Copolymers from a Direct and One‐pot RAFT Synthesis in Water

The syntheses of amphiphilic block copolymers are successfully performed in water by chain extension of hydrophilic macromolecules with styrene at 80 °C. The employed strategy is a one‐pot procedure in which poly(acrylic acid), poly(methacrylic acid) or poly(methacrylic acid‐co‐poly(ethylene oxide) methyl ether methacrylate) macroRAFTs are first formed in water using 4‐cyano‐4‐thiothiopropylsulfanyl pentanoic acid (CTPPA) as a chain transfer agent. The resulting macroRAFTs are then directly used without further purification for the RAFT polymerization of styrene in water in the same reactor. This simple and straightforward strategy leads to a very good control of the resulting amphiphilic block copolymers.

     

Oligo(glycerol) Methacrylate Macromonomers

Linear, protected ω‐methoxy oligo(glycerol) methacrylate (OGly^PMA) macromonomers are synthesized via anionic ring‐opening polymerization of ethoxyethyl glycidyl ether (EEGE) followed by termination with methacrylic acid anhydride ( = 3–11, PDI < 1.30). The covalently bound methacrylate moiety allows the homopolymerization of OGly^PMA as well as copolymerization with low molecular weight comonomers. In homopolymerizations, macromonomers are polymerized by atom transfer radical polymerization (ATRP) yielding well‐defined graft polymers ( = 20 000–30 000 g mol⁻¹). Acidic hydrolysis of the protecting groups releases water‐soluble polyhydroxy‐functional structures. First results on the copolymerization with 2‐hydroxyethyl methacrylate (HEMA) are given in the final part of this work.     

Fabrication of biodegradable poly(trimethylene carbonate) networks for potential tissue engineering scaffold applications

Biodegradable poly(trimethylene carbonate) (PTMC) networks were prepared by photopolymerization of linear (L)‐ and star (S)‐shaped PTMC macromonomers for potential tissue engineering scaffold applications. The L‐ (M_n, 6400) and S‐shaped (M_n, 5880) PTMC macromonomers were synthesized using 1,4‐butane diol and 2‐ethyl‐ 2‐hydroxyl‐propane‐1,3‐diol co‐initiated ring‐opening polymerization of trimethylene carbonate (TMC) in the presence of stannous octoate and subsequent acrylation with acryloyl chloride. Chemical structures of the PTMC macromonomers and their corresponding networks were characterized by ¹H NMR and ¹³C NMR spectroscopy. The human endothelial cell line, EA.hy926 was used to test the biocompatibility, cell adhesion, and proliferation behavior of both PTMC networks. The PTMC networks made from the S‐shaped macromonomers exhibited superior cell adhesion and proliferation behavior than those made of the linear macromonomers. Copyright © 2008 John Wiley & Sons, Ltd.     

Amphiphilic Block‐Graft Copolymers with a Degradable Backbone and Polyethylene Glycol Pendant Chains Prepared via Ring‐Opening Polymerization of a Macromonomer

Well‐defined amphiphilic block‐graft copolymers PCL‐b‐[DTC‐co‐(MTC‐mPEG)] with polyethylene glycol methyl ether pendant chains were designed and synthesized. First, monohydroxyl‐terminated macroinitiators PCL‐OH were prepared. Then, ring‐opening copolymerization of 2,2‐dimethyltrimethylene carbonate (DTC) and cyclic carbonate‐terminated PEG (MTC‐mPEG) macromonomer was carried out in the presence of the macroinitiator in bulk to give the target copolymers. All the polymers were characterized by ¹H NMR and gel permeation chromatography (GPC). The polymers have unimodal molecular weight distributions and moderate polydispersity indexes. The amphiphilic block‐graft copolymers self‐assemble in water forming stable micelle solutions with a narrow size distribution.

     

Synthesis of polybutadiene‐based particles via dispersion ring‐opening metathesis polymerization

Latex particles based on 1,4‐polybutadiene were synthesized via dispersion ring‐opening metathesis copolymerization of 1,5‐cyclooctadiene with a α‐norbornenyl poly(ethylene oxide) macromonomer. Stable but polydisperse colloidal dispersions in the 50 nm to 10 μm size range were obtained. In this work, particular attention was paid to the effects of the kinetics of copolymerization on the structure of the graft copolymers formed and on the onset of turbidity. Strategies to prepare monodisperse polybutadiene particles were also designed through the growth of a polybutadiene shell from a well‐defined polynorbornene seed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1154–1163, 2004     

Substituted propenyl end groups as reactive intermediates in radical polymerization

The addition of propagating radicals of methyl acrylate (MA) and styrene (St) to CH₂?C(CO₂CH₃)CH₂? and CH₂?C(C₆H₅)CH₂? ω‐end groups of poly(methyl methacrylate) (PMMA) and polystyrene (PSt) was investigated. The end groups were as reactive as MA and St toward the poly(methyl acrylate) (PMA) and PSt radicals, respectively. The adduct radical derived from the two types of PMMA end groups and PMA radicals underwent β fragmentation exclusively to yield PMMA radicals and end groups bound to PMA chains. The addition of PSt radicals to PMMA with CH₂?C(CO₂Me)CH₂? end groups resulted in adduct radicals that underwent β fragmentation and addition to St or coupling with PSt radicals. Adduct radicals formed by the addition of PMA radicals to both types of end groups of PSt exclusively formed C? C bond by coupling with PMA radicals to form branched structures or by addition to MA monomer to give a copolymer. The fate of the adduct radicals was highly dependent on the type of polymer chain and the substituent bound to the end group. Steric congestion of the adduct radical arising from the α‐methyl group of the PMMA chain was considered to be crucial for fragmentation to expel the PMMA radical. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 645–654, 2003     

Anionic homo‐ and copolymerization of styrenic triple‐tailed polybutadiene macromonomers

A number of well‐defined complex macromolecular architectures have been synthesized using an efficient macromonomer technique. Styrenic triple‐tailed polybutadiene (PBd) macromonomers (sTMMB), synthesized by selective reaction (titration) of living PBd tails with the SiCl groups of 2‐(dichloromethylsilyl)ethylchloromethylsilyl‐4‐styrene (TCDSS), were polymerized in situ without isolation of sTMMB with s‐BuLi, using high vacuum techniques. Taking advantage of the living character of the anionic polymerization of sTMMB, the following complex macromolecular architectures were prepared: PBd‐g‐(PBd)₃ (triple‐combs), PS‐g‐(PBd)₃ (triple‐grafts), [PBd‐g‐(PBd)₃]₃ (3‐arm triple‐comb stars), and triple molecular brushes (tmbPBd) or triple polymacromonomers (tPMMB). Characterization carried out by size exclusion chromatography (SEC), equipped with refractive index and light scattering detectors, indicated that the synthesized novel architectures have a high degree of molecular and compositional homogeneity. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3513–3523, 2007