Amine functionalization of poly(styryl)lithium with N-(benzylidene)trimethylsilylamine

Functionalization reactions of poly(styryl)lithium with N-(benzylidene)-trimethylsilylamine produce polymers containing significant amounts of coupling products for M_n = 2.8 × 10³g/mol (19% coupling) and M_n = 15 × 10³g/mol (15% coupling). Isolation and characterization of the products for the amination of poly(styryl)lithium with M_n = 2.8 × 1³g/mol indicates that the non-coupled products consist of a primary amine-terminated polymer (69% yield) and an acetophenone-type functionalized polymer (12% yield). The dimeric product (19% yield) has a primary amine functional group. The formation of these products is rationalized by a Cannizzaro-type reaction of the initially formed polymeric lithium silylamide product with excess N-(benzylidene)(trimethylsilylamine to form the corresponding polymer with imine chain-end functionality which can react with another molecule of poly(styryl)lithium to form dimer product or hydrolyze to the acetophenone functionality on work-up.     

Synthesis and self-association in aqueous media of poly(ethylene oxide)/poly(ethyl glycidyl carbamate) amphiphilic block copolymers

New temperature sensitive AB, ABA, and BAB amphiphilic block copolymers consisting of hydrophilic poly(ethylene oxide) and hydrophobic poly(ethyl glycidyl carbamate) blocks were synthesized by anionic polymerization followed by chemical modification reactions. The self-association of the block copolymers in aqueous media was studied by UV-vis spectroscopy and dynamic and static light scattering. The obtained block copolymers spontaneously form micelles in aqueous media. The critical micellization concentration varied from 0.5 to 4 g/L depending on the copolymer architecture and composition. The influence of the temperature upon the self-association of the block copolymers was investigated. The increase of temperature did not affect the value of the critical micellization concentration, but led to the formation of better defined micelles with narrow size distribution.     

One-step synthesis of α-p-vinylphenylalkyl-ω-hydroxy poly(ethylene oxide) macromonomers by anionic polymerization initiated from p-vinylphenylalkanols

ω-(p-Vinylphenyl)alkanols, including methanol, ethanol, propanol, pentanol, and hexanol, have been partially alkoxidated with potassium naphthalene to initiate anionic polymerization of ethylene oxide (EO) in order to directly prepare the corresponding α-p-vinylphenylalkyl-ω-hydroxy poly(ethylene oxide) (PEO) macromonomers. p-Vinylphenylmethanol, i.e. p-vinylbenzyl alcohol (VBA) afforded the expected well-defined macromonomer via living polymerization mechanism and the kinetics have been examined as a function of extent of potassium-alkoxidation. Other alcohols such as p-vinylphenylpropanol (VPP), -pentanol (VPPT), and -hexanol (VPH) were also successful to afford the corresponding PEO macromonomers, while p-vinylphenylethanol (VPE) alkoxide polymerized EO to give p-divinylbenzene and poly(ethylene glycol) without p-vinylphenylethoxy end group, which were supposed to form by a very facile intramolecular chain transfer of the activated oligomeric alkoxide chain end to abstract a benzylic proton of the initiating fragment.     

Syntheses of well-defined poly(siloxane)-b-poly(styrene) and poly(norbornene)-b-poly(styrene) block copolymers using functional alkoxyamines

Functional alkoxyamines, 1-[4-(4-lithiobutoxy)phenyl]-1-(2,2,6,6-tetramethylpiperidinyl-N-oxyl)ethane (2) and 1-[4-(2-vinyloxyethoxy)phenyl]-1-(2,2,6,6-tetramethylpiperidinyl-N-oxyl)ethane (3) were prepared, and well-defined poly(hexamethylcyclotrisiloxane)-b-poly(styrene)[poly(D₃)-b-poly(St)] and poly(norbornene)-b-poly(St) [poly(NBE)-b-poly(St)] were prepared using the alkoxyamines. The first step was preparation of poly(D₃) and poly(NBE) macroinitiators, which were obtained by the ring-opening anionic polymerization of D₃ using 2 as an initiator and the ring-opening metathesis polymerization of NBE using 3 as a chain transfer. The radical polymerization of St by the poly(D₃) and poly(NBE) macroinitiators proceeded in the ‘living’ fashion to give well-defined poly(D₃)-b-poly(St) and poly(NBE)-b-poly(St) block copolymers.     

Antimicrobial functionalization of poly(ethylene terephthalate) fabrics with waterborne N‐halamine epoxides

A water dispersible terpolymer of [2‐(methacryloyloxy)ethyl]trimethylammonium chloride, glycidyl methacrylate and hydantoinyl acrylamide was synthesized and coated on poly(ethylene terephthalate) fabrics through a pad‐dry‐cure procedure. The coatings were rendered biocidal upon exposure to dilute household bleach solution. The halogenated fabrics exhibited great antimicrobial functionality with about six logs inactivation of S. aureus and E. coli O157:H7 within only two min of contact time. Moreover, the coatings were found to be very stable against repeated washings and UVA light exposure. It was shown that [2‐(methacryloyloxy)ethyl]trimethylammonium monomer is very useful in preparing waterborne N‐halamines which can impart rechargeable, effective, and stable antimicrobial coatings to poly(ethylene terephthalate) fabrics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43088.     

Dithioester functionalization of poly(cyclohexene oxide) and its application to obtain block copolymers

A new method of introducing dithioester groups into the polymer chain of poly(cyclohexene oxide) is reported. It includes the use of diaryliodonium salt and an aromatic dithioacid as a redox couple to initiate the cationic polymerization of cyclohexene oxide. It was found that the dithioacid by itself cannot start the polymerization of cationic polymerizable monomers; however, in combination with a diaryliodonium salt, an exothermic reaction was produced, yielding a thiocarbonylthio‐functionalized polyether. Thermal profiles of the redox polymerizations were determined by means of optical pyrometry. A preliminary study showed that when the poly(cyclohexene oxide) functionalized with dithioester groups was introduced into the radical polymerization of styrene, the polystyryl growing radicals reacted with the dithioester‐functionalized polyether to form a block polymer. The amount of polyether actually incorporated into the block copolymer was calculated to be 70% of the initial amount of poly(cyclohexene oxide)/dithiobenzoic acid charged into the reactor. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

NMR study of poly(vinylpyrrolidone)/poly(ethylene oxide) blends

Development of polymeric blends has become very important for polymer industries because they have been shown to be successful and versatile alternatives to obtain new polymers. In this work binary blends formed by poly(vinylpyrrolidone) (PVP) and poly(ethylene oxide) (PEO) were studied by solution and solid‐state NMR to determine their physical interaction, homogeneity, and compatibility for use as membranes to separate water/alcohol. The NMR results allowed us to acquire information on the microstructure and molecular dynamic behavior of polymer blends. From the NMR solution it was possible to evaluate the microstructure: PVP presented a preferential syndiotactic distribution sequence and PEO presented two regions, one crystalline and the other amorphous. Considering the solid‐state NMR results it was possible to evaluate the molecular dynamics and all binary blends, showing that PEO behaves as a plasticizer; some intermolecular interaction was also observed. An important point was to evaluate the microstructure of the carbonyl PVP using cross polarization/magic‐angle spinning (CP/MAS) and CP/MAS/dipolar decoupling that was not observed before. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2820–2823, 2002     

Fine polystyrene latexes with reactive poly(ethylene oxide) –poly(propylene oxide)–poly(ethylene oxide) triblock macrosurfactants in modified miniemulsion polymerization

Polystyrene latexes were produced via a newly accessible miniemulsion polymerization where reactive poly(ethylene oxide)–poly(propylene oxide) –poly(ethylene oxide) triblock macrosurfactants were used to impart the interfacial activity during the emulsification and the reactivity in the polymerization. Through atomic force microscopy studies, it was found that the polystyrene latexes produced were extremely small to about 50 nm in a proper experimental condition, and covered richly with poly(ethylene oxide) groups. The polystyrene latexes were expected to have great applicability in the production of structured latex films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 328–332, 2002     

Simultaneous synthesis and doping of poly(1,6-heptadiyne-co-dipropargyl ether) using ionic initiators

Cyclocopolymerization of 1,6-heptadiyne with dipropargyl ether was carried out under nitrogen atmosphere using KSCN, KBr and KI as initiators in N,N-dimethyl formamide. The course of polymerization was monitored through UV-Vis spectroscopy. The rate of cyclocopolymerization was determined at different polymerization conditions and the relative efficiency of different initiators was evaluated. KSCN was found to be particularly an effective initiator for the copolymerization. The resulting dark brown colour polymer exhibits good solubility in common organic solvents. ¹H-NMR, FTIR and UV-Vis spectra of poly(1,6-heptadiyne-co-dipropargyl ether) revealed that the copolymer possesses cyclic polyene units in the back bone. Doped nature of the polymer was evident from UV-Vis and FTIR spectroscopy. Thermal characteristics, conductivity and electroactivity of the copolymer were also explored.     

NMR study of molecular motion in poly(ethylene oxide)

Summary Proton second moment and spin-lattice relaxation times T₁, T_1e and T_1D for helical poly (ethylene oxide) 5000 over a wide temperature range are measured. The results of CW and pulse experiments corroborate the existence of a motional process in the crystalline region of the polymer interpreted as oscillation or rotation of molecules around their helical axes. The activation energy for this type of motion is found to be 12 kcal/mole.Presented at the 22nd Microsymposium, Characterization of Structure and Dynamics of Macromolecular Systems by NMR Methods, Prague, July 20–23, 1981     

Preparation of star copolymers with three arms of poly(ethylene oxide-co-glycidol)-graft-polystyrene and investigation of their aggregation in water

The star graft copolymers with three arms composed of poly(ethylene oxide) (PEO) as main chain and polystyrene (PS) as side chains were prepared by sequential anionic ring-opening copolymerization of ethylene oxide and ethoxyethyl glycidyl ether (EEGE), and then atom transfer radical polymerization (ATRP) of styrene. The anionic ring-opening copolymerization of EO and EEGE was carried out using 2-ethyl-2-hydroxymethyl-1,3-propanediol as trifunctional initiator and diphenylmethyl potassium (DPMK) as deprotonating agent. The resulting three-arm star copolymer [poly(EO-co-EEGE)]₃ could be easily hydrolyzed to unmask the pendant hydroxyl groups without affecting the PEO chains. The switch from the first to the second mechanism was completed by the reaction of the multi-pendant hydroxyl groups of three-arm PEO chain with 2-bromoisobutyryl bromide. The obtained poly(ethylene oxide-co-2-bromoisobutyryloxyglycidyl ether), [poly(EO-co-BiBGE)]₃, was used as macroinitiators to initiate the polymerization of styrene in bulk at 90 °C by ATRP. The final products and intermediates were characterized by NMR, SEC and IR in detail. The amphiphilic star graft copolymers synthesized can form micelles in water. The critical micelle concentration (cmc) determined by fluorescence spectra was about 5 × 10⁻⁷ g/mL. Sphere micelles were observed by transmission electron microscopy (TEM) at low copolymer concentration (6 × 10⁻⁵ g/mL), but the micelle shape became irregular when the copolymer concentration increased to 6 × 10⁻⁴ g/mL.     

Surface modification of poly(ethylene terephthalate) fibers via controlled radical graft polymerization

Functional chemical modifications on poly(ethylene terephthalate) (PET) fibers via radical graft polymerization could be controlled by managing mutual interactions and affinities between different components in the grafting reaction system. Hansen solubility parameters was used as a tool to quantify affinities of related agents and the polymer, and provided reliable results. The latest results proved the practicality of using Hansen solubility parameters in controlling radical graft polymerizations on surface modifications of PET fibers. Four different monomers with different hydrophilic properties in different solvent and initiator systems were examined, and results confirmed that interactions of initiator‐PET, initiator‐solvent, monomer‐PET, monomer‐solvent, and monomer‐initiator play important roles in determining the grafting reaction efficiency. Results revealed that for the selected grafting systems studied, hydrophilic monomers presented overall favoring affinities toward PET leading to higher grafting yields compared to hydrophobic monomers. The results have instructive impact to commercial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45990.     

Synthesis of monomethoxy poly(ethylene glycol) without diol poly(ethylene glycol)

Since monomethoxy poly(ethylene glycol) (mPEG) inevitably contains diol PEG and is difficult to get high molecular weight through traditional synthesis at high temperature under high pressure, a novel synthetic technique via anionic solution polymerization was reported in this study. With a new initiating system, potassium naphthalene and methanol, was introduced, the polymerization proceeded at ambient temperature and side reactions were well restrained. Furthermore, a slight excess of potassium naphthalene can effectively remove the trace of water and oxygen in the reaction system. Under this condition, mPEG was nearly quantitatively obtained without containing diol PEG. Its Mn ranged from 1 to 30 kDa and the polydispersity was kept lower than 1.07. Characterization of the mPEG obtained was carried out using GPC to determine the content of diol PEG and ¹H‐NMR and MALDI‐ToF MS spectroscopic analysis to confirm the exact structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Ionic conductivities for poly(ethylene oxide) complexes with lithium salts of monobasic and dibasic acids and blends of poly(ethylene oxide) with lithium salts of anionic polymers

Lithium salts of two polyanionic addition polymers containing alkyl sulphonic acid and perfluoroalkyl carboxylic acid side groups were prepared. Blends of these polymers were formed with poly(ethylene oxide) (PEO). The blend containing alkyl sulphonate units showed some phase separation but this was not observed for the blend containing perfluoroalkyl carboxylate groups. In the latter case a comparatively high conductivity of $\text{～10}{}^{\mathrm{?5}}\text{Ω}{}^{\mathrm{?1}}$ cm^?1 at 374 K was obtained. The anionic units in these blends are expected to be virtually immobile. Complexes formed from PEO and the Li-salt of hexafluoroglutaric acid had similar high ionic conductivities and there are grounds for supposing that the anions in these complexes may also be substantially immobilized. In addition, conductivity values were obtained for some PEO complexes containing lithium salts of some monobasic acids and it was found that the complex formed from the Li-salt of the strongest acid gave the highest conductivity ($\text{～4 × 10}{}^{\mathrm{?4}}\text{Ω}{}^{\mathrm{?1}}$ cm^?1 at 373 K for a PEO-LiSO₃CF₃ complex).     

Analysis of poly(ethylene oxide)-b-poly(propylene oxide) block copolymers by MALDI-TOF mass spectrometry using collision induced dissociation

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to analyse the block length of commercially available block copolymers of poly(ethylene oxide) and poly(propylene oxide) (PEO-b-PPO) based on the fragmentation behaviour in collision induced dissociation (CID) experiments.MALDI-CID-TOF² analysis is a complex procedure depending on a number of different experimental parameters. Therefore, a step-by-step procedure was used starting with PEG and PPG standards, PEG-PPG blends and endgroup-functionalized PPGs, to understand the fragmentation behaviour of the different species. These results showed that characteristic fragment patterns of the homopolymers and PEG-PPG mixtures can be obtained that facilitate the interpretation of the fragment spectra of PEO-b-PPO di- and triblock copolymers. It was found that di- and triblock copolymers can be differentiated by their fragment spectra. In addition, the sequence of monomer units in the diblock copolymers could be determined.     

Surface functionalization of poly(vinylidene fluoride) membrane by radiation-induced emulsion polymerization of hydroxyethyl acrylates in an aqueous medium

Decades ago, surface modification of poly(vinylidene fluoride) (PVDF) membrane became an essential subject. The change is mainly to enhance the hydrophilicity properties of the membrane in order to increase the adsorption capacity, thus making as a novel adsorbent. This study aims to used radiation-induced polymerization and compares the final properties of PVDF grafted hydroxyethyl acrylates (HEA) prepare by two different approaches. The PVDF-grafted-HEA has achieved either direct polymerization or emulsion polymerization. Tween-20 has been used as a surfactant in emulsion polymerization. The final PVDF-grafted poly-HEA was analyzed using several different instruments to observe the changes in terms of morphological structure, topography properties, thermal stability, mechanical strength, and hydrophilicity. Significant differences were seen in morphology and contact angles properties. By emulsion polymerization, poly-HEA grafted in the shape of micelles compare to by direct polymerization shown a thin homogenous layer. Thus, the surface roughness of PVDF by emulsion is higher lead to higher contact angles. Even though both approaches demonstrate significant changes in the physicochemical properties of the PVDF membrane, it is revealed that radiation-induced direct polymerization approaches could achieve a hydrophilic PVDF-grafted HEA.     

Biodegradable block copolymers with poly(ethylene oxide) and poly(glycolic acid‐valine) blocks

Biodegradable ABA triblock copolymers with poly(ethylene oxide) and poly(glycolic acid‐valine) blocks were synthesized via ring‐opening polymerization of cyclo(glycolic acid‐valine) using Ca‐alcoholates of hydroxytelechelic PEO as the initiator. The L‐valine residue racemized during copolymerization of cyclo(glycolic acid‐valine). The crystallization of the block copolymers decreases with decreasing PEO content in the triblock copolymers and with increasing length of the poly(glycolic acid‐valine) block. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2916–2919, 2002     

Immobilization of poly(ethylene oxide) on poly(ethylene terephthalate) using a plasma polymerization process

Poly(ethylene oxide) (PEO) has been covalently immobilized on poly(ethylene terephthalate) (PET) films using a radio frequency glow discharge polymer deposition process, followed by chemical coupling. Amino or hydroxyl groups were introduced onto the surface of the PET by exposing the films to allylamine and allyl alcohol plasmas. These functional groups were activated with cyanuric chloride, and then they were reacted with PEO. ESCA and water contact angle studies were used to characterize the surfaces of these films during the different stages of the reaction. The films containing the higher molecular weight PEO exhibited an increase in the ? C? O? peak of the C_ls ESCA spectrum and an increase in oxygen content on the film surfaces. Increasing the molecular weight of the PEO attached to the PET also resulted in an increased wettability of the films.     

Reactive compatibilization of poly(methyl acrylate‐ran‐acrylonitrile)/poly(ethylene) blends through amine–anhydride coupling

Methyl acrylate/acrylonitrile copolymers (MA/AN) were reactively compatibilized as the dispersed phase into poly(ethylene) (PE) for potential hydrocarbon barrier materials. The MA/AN was made reactive by including p‐aminostyrene (PAS), yielding terpolymers (MA/AN/PAS) with pendant primary amine functionality (number average molecular weight = 65–133 kg mol^?1, dispersity (?)=1.83–2.53, molar composition of PAS in copolymer F_PAS = 0.03–0.14, molar composition of AN = F_AN = 0.27–0.52). The non‐functional MA/AN and amino functional MA/AN/PAS were each melt blended into PE that was grafted with maleic anhydride (PE‐g‐MAnn) at 200 °C at 70:30 wt % PE‐g‐MAnn:co/terpolymer. After extrusion, the dispersed phase particle size (volume to surface area diameter, ) was coarse (12.6 μm) for the non‐reactive blend whereas it was much lower for the reactive blend ( = 1.2 μm). Coarsening after annealing at 150 °C was slow, but the domain sizes increased only slightly for both cases. The reactive blend was deemed sufficiently stable and thus was suitable as a candidate barrier material for further testing against olefins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44177.     

Sequence analysis of poly(ethylene/1,4-cyclohexanedimethylene terephthalate) copolymer using H and C NMR

The triad-level sequence analysis of poly(ethylene/1,4-cyclohexanedimethylene terephthalate) copolymer was reported in a solvent system of o-chlorophenol/deuterated chloroform mixture (50/50 v/v) at 80 °C using 600 MHz ¹H NMR. The well-resolved alcoholic CH₂ proton peak of the glycol units was observed, which made the detailed sequence analysis possible. The peaks of the cis- and trans-forms of the 1,4-cyclohexanedimethylene glycol units were split into the triad sequence in the chain and could be assigned by a comparison of the spectra with those of homopolymers and by an additional two-dimensional heteronuclear multiple bond correlation observation. The triad sequence distributions centered on 1,4-cyclohexanedimethylene glycol units were determined, which was independent of the cis- and trans-forms of the units and controlled according to Bernoullian statistics.