Synthesis,characterization, reactivity ratios by nuclear magnetic resonance spectroscopy,and application of (2,5‐Dichlorophenyl acrylate‐co‐glycidyl methacrylate) polymers as adhesives for the leather industry

2,5‐ Dichlorophenyl acrylate (DPA)‐co‐glycidyl methacrylate (GMA) polymers having five different compositions were synthesized in 1,4‐dioxane using benzoyl peroxide as a free‐radical initiator at 70 ± 0.5°C. Using ¹H‐NMR spectroscopy, the composition of the two monomers in the copolymers was calculated by comparing the integral values of the aromatic and aliphatic proton peaks. The reactivity ratios were calculated by Fineman–Ross (r₁ = 0.31 and r₂ = 1.08), Kelen–Tudos (r₁ = 0.40 and r₂ = 1.15), and extended Kelen–Tudos (r₁ = 0.39 and r₂ = 1.16) methods. The nonlinear error‐in‐variables model was used to compare the reactivity ratios. The copolymers were characterized by ¹H and proton decoupled ¹³C‐NMR spectroscopes. Gel permeation chromatography was performed for estimating the M_w and M_n and M_w/M_n of the poly(DPA) and copolymers (DPA‐co‐GMA: 09 : 91 and 50 : 50). Thermal stability of the homo‐ and copolymers was estimated using TGA [poly(DPA) > DPA‐co‐GMA (50 : 50) > DPA‐co‐GMA (09:91)], while DSC was utilized for determining the glass transition temperature. T_g increased with increased DPA content in the copolymer. The 50 : 50 mol % copolymer was chosen for curing with diethanolamine in chloroform. The cured resins were tested for the adhesive properties on leather at different temperatures (50, 90, 100, and 110°C). The resin cured at 50 °C exhibited a maximum peel strength of 1.6 N/mm, revealing a good adhesive behavior. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1167–1174, 2006     

Copolymerization of phenylisocyanate and ϵ‐caprolactone with rare earth chloride systems

A copolymer of phenylisocyanate (PhNCO) and ε‐caprolactone (CL) was synthesized by the rare earth chloride systems lanthanide chloride isopropanol complex (LnCl₃·3iPrOH) and propylene epoxide (PO). Polymerization conditions were investigated, such as lanthanides, reaction temperature, monomer feed ratio, La/PO molar ratio, and aging time of catalyst. The optimum conditions were: LaCl₃ preferable, [PhNCO]/[CL] in feed = 1 : 1 (molar ratio), 30°C, [monomer]/[La] = 200, [PO]/[La] = 20, aging 15 min, polymerization in bulk for 6 h. Under such conditions the copolymer obtained had 39 mol % PhNCO with a 78.2% yield, M_n = 20.3 × 10³, and M_w/M_n = 1.60. The copolymers were characterized by GPC, TGA, ¹H‐NMR, and ¹³C‐NMR, and the results showed that the copolymer obtained had a blocky structure with long sequences of each monomer unit. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2135–2140, 2007     

Atom transfer radical copolymerization of glycidyl methacrylate and methyl methacrylate

Glycidyl methacrylate (GMA) and methyl methacrylate (MMA) copolymers were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of GMA, ranging from 0.28 to 1.0, on the polymer polydispersity index (weight‐average molecular weight/number‐average molecular weight) as the indicator of a controlled process was investigated at 70°C, with ethyl 2‐bromoisobutyrate as an initiator and 4,4′‐dinonyl‐2,2′‐bipyridyne (dNbpy)/CuBr as a catalyst system in anisole. The monomer reactivity ratios (r values) were obtained by the application of the conventional linearization Fineman–Ross method (r_GMA = 1.24 ± 0.02 and r_MMA = 0.85 ± 0.03) and by the Mayo–Lewis method (r_GMA = 1.19 ± 0.04 and r_MMA = 0.86 ± 0.03). The molecular weights and polydispersities of the copolymers exhibited a linear increase with GMA content. The copolymer compositions were determined by ¹H‐NMR and showed a domination of syndiotactic structures. The glass‐transition temperatures (T_g) of the copolymers analyzed by differential scanning calorimetry (DSC) decreased in the range 105–65°C with increasing GMA units. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Study of a new titanium dual initiator for the synthesis of poly(ε‐caprolactone)‐b‐polystyrene block copolymers by the combination of coordination and nitroxide mediated polymerizations

Poly ε‐caprolactone‐polystyrene block‐copolymers (PCL‐b‐PSt) were synthesized using a modified titanium catalyst as the dual initiator. Alcoholysis of Ti(OPr)₄ by 4‐hydroxy 2,2,6,6 tetramethyl piperidinyl‐1‐oxyl (HO‐TEMPO) gave a bifunctional initiator Ti(OTEMPO)₄. Poly ε‐caprolactone prepolymer end‐capped with the nitroxide group was first prepared by ring opening polymerization of ε‐caprolactone with this initiator at high conversion. The nitroxide‐end‐capped structure and molar mass (M_n) of the polymers were demonstrated by typical UV absorption band. This analytical technique indicates a near‐quantitative nitroxide functionality and a M_n in good agreement with size exclusion chromatography (SEC) ones. This polyester prepolymer was used to further initiate the radical polymerization with styrene and reach the block copolymers (PCL‐b‐PSt). All the prepolymers and block copolymers were characterized by SEC and NMR spectroscopy. Additionally, the preparation of star polymers bearing two kinds of arms (PCL and PSt) was envisaged and a preliminary result was given. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and physicochemical characterization of amphiphilic block copolymer self‐aggregates formed by poly(ethylene glycol)‐block‐poly(ϵ‐caprolactone)

Diblock copolymers with different poly(ε‐caprolactone) (PCL) block lengths were synthesized by ring‐opening polymerization of ε‐caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG‐OH, MW 2000) as initiator. The self‐aggregation behaviors and microscopic characteristics of the diblock copolymer self‐aggregates, prepared by the diafiltration method, were investigated by using ¹H NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG–PCL block copolymers formed the self‐aggregate in an aqueous environment by intra‐ and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations of the block copolymer self‐aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The partition equilibrium constants (K_v) of pyrene, measured by fluorescence spectroscopy, revealed that the inner core hydrophobicity of the nanoparticles increased with increasing PCL chain length. The aggregation number of PCL chain per one hydrophobic microdomain, investigated by the fluorescence quenching method using cetylpyridinium chloride as a quencher, revealed that 4–20 block copolymer chains were needed to form a hydrophobic microdomain, depending on PCL block length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3520–3527, 2006     

Synthesis and characterization of the novel block copolymer poly(ε‐caprolactone)‐b‐poly(4‐vinyl pyridine) by the combination of coordination and controlled free‐radical polymerizations

A novel block copolymer, poly(ε‐caprolactone)‐b‐poly(4‐vinyl pyridine), was synthesized with a bifunctional initiator strategy. Poly(ε‐caprolactone) prepolymer with a 2,2,6,6‐tetramethylpiperidinyloxy (TEMPO) end group (PCL_T) was first obtained by coordination polymerization, which showed a controlled mechanism in the process. By means of ultraviolet spectroscopy and electron spin resonance spectroscopy, the TEMPO moiety was determined to be intact in the polymerization. The copolymers were then obtained by the controlled radical polymerization of 4‐vinyl pyridine in the presence of PCL_T. The desired block copolymers were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and NMR spectroscopy in detail. Also, the effects of the molecular weight and concentration of PCL_T on the copolymerization were investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2280–2285, 2004     

Preparation and characterization of a type of ladder‐like poly(phenyl silsesquioxane) based hybrid star‐shaped copolymer of ε‐caprolactone

Combination of the organic–inorganic hybrid such as silsesquioxane with ε‐caprolactone will lead to materials expected to be environmentally friendly and applicable to biomedical usages. A ladder‐like poly(phenyl silsesquioxane) based hybrid star‐shaped copolymer of ε‐caprolactone was prepared by ring opening polymerization of ε‐caprolactone catalyzed by Sn(Oct)₂ with hydroxyl terminated ladder‐like poly(phenyl silsesquioxane) as initiator. The copolymers were characterized by proton nuclear magnetic resonance (¹H‐NMR), silicon nuclear magnetic resonance (²⁹Si‐NMR), Fourier‐transform infrared spectrometer (FT‐IR), size exclusion chromatography (SEC), thermo gravimetric analysis (TGA), and differential scanning calorimetry (DSC) in detail. Furthermore, the enzymatic degradation property of the copolymers was also investigated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42335.     

Synthesis and aggregation behavior of four types of different shaped PCL‐PEG block copolymers

Biodegradable, amphiphilic, linear (diblock and triblock) and star‐shaped (three‐armed and four‐armed) poly[(ethylene glycol)‐block‐(ε‐caprolactone)] copolymers (PEG–PCL copolymers) were synthesized by ring‐opening polymerization of ε‐caprolactone (CL) with stannous octoate as a catalyst, in the presence of monomethoxypoly(ethylene glycol) (MPEG), poly(ethylene glycol) (PEG), three‐armed poly(ethylene glycol) (3‐arm PEG) or four‐armed poly(ethylene glycol) (4‐arm PEG) as an initiator, respectively. The monomer‐to‐initiator ratio was varied to obtain copolymers with various PEG weight fractions in a range 66–86%. The molecular structure and crystallinity of the copolymers, and their aggregation behavior in the aqueous phase, were investigated by employing ¹H‐NMR spectroscopy, gel permeation chromatography and differential scanning calorimetry, as well as utilizing the observational data of gel–sol transitions and aggregates in aqueous solutions. The aggregates of the PEG–PCL block copolymers were prepared by directly dissolving them in water or by employing precipitation/solvent evaporation technique. The enthalpy of fusion (ΔH_m), enthalpy of crystallization (ΔH_crys) and degrees of crystallinity (χ_c) of PEG blocks in copolymers and the copolymer aggregates in aqueous solutions were influenced by their PEG weight fractions and molecular architecture. The gel–sol transition properties of the PEG–PCL block copolymers were related to their concentrations, composition and molecular architecture. Copyright © 2006 Society of Chemical Industry     

Novel Poly(linolenic acid) Graft Copolymers: Synthesis,Characterization and Electrical Properties

A poly(linolenic acid)‐g‐poly(tert‐butyl acrylate) graft copolymer was synthesized from polymeric linolenic acid peroxide possessing peroxide groups in the main chain by free radical polymerization of tert‐butyl acrylate. Graft copolymers having structures of poly(linolenic acid)‐g‐poly(caprolactone)‐g‐poly(tert‐butyl acrylate) were synthesized from polymeric linolenic acid, possessing peroxide groups on the main chain by the combination of free radical polymerization of tert‐butyl acrylate and ring‐opening polymerization of ε‐caprolactone in one‐pot. The obtained graft copolymers were characterized by proton nuclear magnetic resonance, gel permeation chromatography, thermal gravimetric analysis, differential scanning calorimetry, and scanning electron microscopy techniques. Furthermore, Au/n‐Si diodes were fabricated with and without poly(linolenic acid)‐g‐poly(caprolactone)‐g‐poly(tert‐butyl acrylate)‐4 to form a new interfacial polymeric layer for the purpose of investigating this polymer's conformity in electronic applications. Some main electrical characteristics of these diodes were investigated using experimental current–voltage measurements in the dark and at room temperature.     

Reactive mixing of PET and PET/PP blends with glycidyl methacrylate–modified styrene‐b‐(ethylene‐co‐olefin) block copolymers

Styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) and styrene‐b‐(ethylene‐co‐propylene) (SEP, SEPSEP) block copolymers with different styrene contents and different numbers of blocks in the copolymer chain were functionalized by melt radical grafting with glycidyl methacrylate (GMA) and employed as compatibilizers for PET‐based blends. Binary blends of PET with both functionalized (SEBS‐g‐GMA, SEP‐g‐GMA, SEPSEP‐g‐GMA) and neat (SEBS, SEP, SEPSEP) copolymers (75 : 25 w/w) and ternary blends of PET and PP (75 : 25 w/w) with various amounts (2.5–10 phr) of both modified and unmodified copolymers were prepared in an internal mixer, and their properties were evaluated by SEM, DSC, melt viscosimetry, and tensile and impact tests. The roles of the chemical structure, grafting degree, and concentration of the various copolymers on blend compatibilization was investigated. The blends with the grafted copolymers showed a neat improvement of phase dispersion and interfacial adhesion compared to the blends with nonfunctionalized copolymers. The addition of grafted copolymers resulted in a marked increase in melt viscosity, which was accounted for by the occurrence of chemical reactions between the epoxide groups of GMA and the carboxyl/hydroxyl end groups of PET during melt mixing. Blends with SEPSEP‐g‐GMA and SEBS‐g‐GMA, at concentrations of 5–10 phr, showed a higher compatibilizing effect with enhanced elongation at break and impact resistance. The effectiveness of GMA‐functionalized SEBS was then compared to that of maleic anhydride–grafted SEBS. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2201–2211, 2005     

Formation of a soluble hyperbranched polymer via initiator–fragment incorporation radical copolymerization of divinyl adipate and isobutyl vinyl ether

The copolymerization of divinyl adipate (DVA) with isobutyl vinyl ether (IBVE) was conducted at 70 and 80 °C in benzene using azobisisobutyronitrile (AIBN), at a concentration as high as 0.50 mol l^?1 as the initiator, where the concentrations of DVA and IBVE were 0.40 and 0.60 mol l^?1, respectively. The copolymerization proceeded homogeneously, without any gelation, to yield soluble copolymers in spite of the high molar ratio of DVA as an excellent cross‐linker for IBVE. The copolymer yield increased with time, and the number‐average molecular weight (M_n = 0.9–2.4 × 10⁴ g mol^?1) from gel permeation chromatography (GPC) and molecular weight distribution (M_w/M_n = 1.5–7.6) of the resulting copolymer increased with copolymer yield. The cyanopropyl group, as a fragment of AIBN, was incorporated as a main constituent in the copolymer, the fraction of which increased from ca 10 to ca 20 % with copolymer yield, hence indicating that the copolymerization is an initiator–fragment incorporation radical polymerization. The copolymers also contained IBVE units (10–30 %) and DVA units with intact double bond (8–36 %) and without double bond (45 %). The intrinsic viscosity of the copolymer was very low (0.1 dl g^?1) at 30 °C in tetrahydrofuran. The results from GPC–multi‐angle laser light scattering (MALLS), transmission electron microscopy (TEM) and MALLS revealed that individual copolymer molecules were formed as hyperbranched nanoparticles. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of ABA triblock and novel multiblock copolymers from ethylene glycol,L‐lactide,and ϵ‐caprolactone

Three types of copolymers were synthesized and characterized. First, triblock ABA copolymers [where A is a homopolymer of ?‐caprolactone and B is poly(ethylene glycol)] were prepared by the ring‐opening polymerization of poly(ethylene glycol) with ?‐caprolactone in the presence of stannous octoate (Sn(Oct)₂). The spectral, thermal, and mechanical properties of one sample of these copolymers were studied, and it was discovered that these types of copolymers were more hydrophilic, possessed lower melting points, and had superior mechanical properties (greater toughness) than poly(?‐caprolactone). Second, triblock ABA copolymers [where A is a homopolymer of L ‐lactide and B is poly(ethylene glycol)] were prepared by the ring‐opening polymerization of poly(ethylene glycol) with L ‐lactide in the presence of Sn(Oct)₂. The mechanical properties of these copolymers were studied, and it was found that they were tougher and softer than poly(L ‐lactide). Third, novel ABA triblock copolymers [where A is a copolymer of ?‐caprolactone and L ‐lactide and B is poly(ethylene glycol)] were prepared, and ¹H‐NMR and ¹³C‐NMR spectra of these copolymers indicated a microblock structure for the two end blocks. The stress–strain behavior revealed low yields and high toughness for these copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2072–2081, 2002     

Domain structure and miscibility studies of blends of styrene–butadiene–styrene block copolymers (SBS) and styrene–glycidyl methacrylate statistical copolymers (PS‐GMA) using SAXS and DMTA

The domain structure and miscibility in the solid state of a series of blends of styrene‐butadiene‐styrene (SBS) block copolymers and styrene‐glycidyl methacrylate (PS‐GMA) statistical copolymers with varying molecular weights and compositions were studied using small angle X‐ray scattering and dynamic mechanical thermal analysis. Depending on the molecular characteristics of each component, different types and degrees of solubilization of PS‐GMA in SBS were found which, in addition to the initially SBS phase morphology, lead to materials with multiphase domain morphologies with differences in size and structure. The degree of solubilization of PS‐GMA into the PS domains of SBS was found to be higher for blends containing PS‐GMA with lower molecular weight (M_w = 18 100 g mol^?1) and lower GMA content (1 wt%) and/or for SBS with higher PS content (39 wt%) and longer PS blocks (M_w = 19 600 g mol^?1). Localized solubilization of PS‐GMA in the middle of PS domains of SBS was found to be the most probable to occur for the systems under study, causing swelling of PS domains. However, uniform solubilization was also observed for SBS/PS‐GMA blends containing SBS with composition in the range of a morphological transition (PS block M_w = 19 600 g mol^?1 and 39 wt% of PS) causing a morphological transition in the SBS copolymer (cylinder to lamella). Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Polyethylene‐block‐poly(ε‐caprolactone) diblock copolymers: synthesis and compatibility

A strategy is introduced for the synthesis of polyethylene‐block‐poly(ε‐caprolactone) block copolymers by a combination of coordination polymerization and ring‐opening polymerization. First, end‐hydroxylated polyethylene (PE‐OH) was prepared with a one‐step process through ethylene/3‐buten‐1‐ol copolymerization catalyzed by a vanadium(III) complex bearing a bidentate [N,O] ligand ([PhN?C(CH₃)CHC(Ph)O]VCl₂(THF)₂). The PE‐OH was then used as macroinitiator for ring‐opening polymerization of ε‐caprolactone, leading to the desired nonpolar/polar diblock copolymers. The block structure was confirmed by spectral analysis using ¹H NMR, gel permeation chromatography and differential scanning calorimetry. The unusual topologies of the model copolymers will establish a fundamental understanding for structure–property correlations, e.g. compatibilization, of polymer blends and surface and interface modification of other polymers. © 2014 Society of Chemical Industry     

Biodegradable and photocurable multiblock copolymers with shape‐memory properties from poly(ε‐caprolactone) diol,poly(ethylene glycol), and 5‐cinnamoyloxyisophthalic acid

Biodegradable and photocurable multiblock copolymers of various compositions were synthesized by the high‐temperature solution polycondensation of poly(ε‐caprolactone) (PCL) diols of molecular weight (M_n) = 3000 and poly(ethylene glycol)s (PEG) of M_n = 3000 with a dichloride of 5‐cinnamoyloxyisophthalic acid (ICA) as a chain extender, followed by irradiation by a 400 W high‐pressure mercury lamp (λ > 280 nm) to form a network structure. The gel contents increased with photocuring time, reaching a level of over 90% after 10 min for all copolymers without a photoinitiator. The thermal and mechanical properties of the photocured copolymers were examined by DSC and tensile tests. In cyclic thermomechanical tensile tests, the photocured ICA/PCL/PEG copolymer films showed good shape‐memory properties at 37–60°C, with both shape fixity ratio and shape recovery ratio over 90% at a maximum tensile strain of 100–300%. The water absorption of these copolymers and their rate of degradation in a phosphate buffer solution (pH 7.0) at 37°C increased significantly with increasing PEG content. The novel photocured ICA/PCL/PEG multiblock copolymers are potentially useful in biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Composites Between Alumina and an Ester‐Ether‐Ester Bioresorbable Copolymer

Composites between alumina and the bioresorbable poly(ε‐caprolactone)‐block‐poly(oxyethylene)‐block‐poly(ε‐caprolactone) copolymer were obtained by reacting ε‐caprolactone with preformed poly(ethylene glycol), in the presence of ceramic alumina powder, at 185°C under vacuum. The mechanical properties, tested by compression and flexural strengths and Young's modulus, show that the copolymer interacts poorly with the alumina grains. Both scanning electron and atomic force microscopy show a scarce wettability between alumina and copolymer, as well as the aggregation of alumina micro‐particles into clusters of big size. Both mechanical and morphological tests seem to indicate a stronger interaction between the alumina micro‐particles than between the alumina surface and the reaction mixture during the polymerization, as well as a “compacting effect” by alumina on the forming copolymer. The FT‐IR spectra of the composites show both copolymer and alumina absorption bands. The FT‐IR analysis on the fractions of an extraction with CHCl₃ indicates the presence of traces of poly(ε‐caprolactone), stably linked to alumina. The polymerization of ε‐caprolactone with alumina alone in the same conditions gives poly(ε‐caprolactone), mainly free and in minor part linked to the alumina surface. Two polymerization mechanisms, simultaneously occurring, are proposed. The most relevant result of this work is the lack of chemical inertness of alumina towards ε‐caprolactone, which leads to reconsider also the use of alumina as a biochemically inert material.     

Self‐assembled micelles prepared from poly(ɛ‐caprolactone)–poly(ethylene glycol) and poly(ɛ‐caprolactone/glycolide)–poly(ethylene glycol) block copolymers for sustained drug delivery

A series of poly(?‐caprolactone)–poly(ethylene glycol) (PCL‐PEG) and poly(?‐caprolactone/glycolide)–poly(ethylene glycol) [P(CL/GA)‐PEG] diblock copolymers were prepared by ring‐opening polymerization of ?‐caprolactone or a mixture of ?‐caprolactone and glycolide using monomethoxy PEG (mPEG) as macroinitiator and Sn(Oct)₂ as catalyst. The resulting copolymers were characterized using ¹H‐NMR, gel permeation chromatography, differential scanning calorimetry, and wide‐angle X‐ray diffraction. Copolymer micelles were prepared using the nanoprecipitation method. The morphology of the micelles was spherical or worm‐like as revealed by transmission electron microscopy, depending on the copolymer composition and the length of the hydrophobic block. Introduction of the glycolide component, even in small amounts (CL/GA = 10), disrupted the chain structure and led to the formation of spherical micelles. Interestingly, the micelle size decreased with the encapsulation of paclitaxel. Micelles prepared from mPEG5000‐derived copolymers exhibited better drug loading properties and slower drug release than those from mPEG2000‐derived copolymers. Drug release was faster for copolymers with shorter PCL blocks than for those with longer PCL chains. The introduction of glycolide moieties enhanced drug release, but the overall release rate did not exceed 10% in 30 days. In contrast, drug release was enhanced in acidic media. Therefore, these bioresorbable micelles and especially P(CL/GA)‐PEG micelles with excellent stability, high drug loading content, and prolonged drug release could be promising for applications as drug carriers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45732.     

Synthesis of poly(fluorinated styrene)‐block‐poly(ethylene oxide) amphiphilic copolymers via atom transfer radical polymerization: potential application as paper coating materials

BACKGROUND: The surface of a substrate which comprises a fibrous material is brought into contact with a type of amphiphilic block copolymer which comprises hydrophilic/hydrophobic polymeric blocks. These amphiphilic copolymers have been synthesized by atom transfer radical polymerization (ATRP) technique. The atom transfer radical polymerization of poly(2,3,4,5,6‐pentafluorostyrene)‐block‐poly(ethylene oxide) (PFS‐b‐PEO) copolymers (di‐ and triblock structures) with various ranges of PEO molecular weights was initiated by a PEO chloro‐telechelic macroinitiator. The polymerization, carried out in bulk and catalysed by copper(I) chloride in the presence of 2,2′‐bipyridine ligand, led to A–B–A amphiphilic triblock and A–B amphiphilic diblock structures. RESULTS: With most of the macroinitiators, the living nature of the polymerizations led to block copolymers with narrow molecular weight distributions (1.09 < M_w/M_n < 1.33) and well‐controlled molecular structures. These block copolymers turned out to be water‐soluble through adjustment of the PEO block content (>90 wt%). Of all the block copolymers synthesized, PFS‐b‐PEO(10k)‐b‐PFS containing 10 wt% PFS was found to retard water absorption considerably. CONCLUSION: The printability of paper treated with the copolymers was evaluated with contact angle measurements and felt pen tests. The adsorption of such copolymers at the solid/liquid interface is relevant to the wetting and spreading of liquids on hydrophobic/hydrophilic surfaces. Copyright © 2009 Society of Chemical Industry     

Biodegradable poly(vinyl alcohol)‐graft‐ poly(ε‐caprolactone) comb‐like polyester: Microwave synthesis and its characterization

Poly(vinyl alcohol)‐initiated microwave‐assisted ring opening polymerization of ε‐caprolactone in bulk was investigated, and a series of poly(vinyl alcohol)‐graft‐poly(ε‐caprolactone) (PVA‐g‐PCL) copolymers were prepared, with the degree of polymerization (DP) of PCL side chains and the degree of substitution (DS) of PVA by PCL being in the range of 3–24 and 0.35–0.89, respectively. The resultant comb‐like PVA‐g‐PCL copolymers were confirmed by means of FTIR, ¹H NMR, and viscometry measurement. The introduction of hydrophilic backbone resulted in the decrease in both melting point and crystallization property of the PVA‐g‐PCL copolymers comparing with linear PCL. With higher microwave power, the DP of PCL side chains and DS of PVA backbone were higher, and the polymerization reaction proceeded more rapidly. Both the DP and monomer conversion increased with irradiation time, while the DS increased first and then remained constant. With initiator in low concentration, the DP and DS were higher, while the monomer was converted more slowly. Microwaves dramatically improved the polymerization reaction in comparison of conventional heating method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3973–3979, 2007     

Synthesis of poly(octadecyl acrylate‐b‐styrene‐b‐octadecyl acrylate) triblock copolymer by atom transfer radical polymerization

The synthesis of triblock copolymer poly(octadecyl acrylate‐b‐styrene‐b‐octadecyl acrylate), using atom transfer radical polymerization (ATRP), is reported. The copolymers were prepared in two steps. First, polystyrene was synthesized by ATRP using α,α′‐dichloro‐p‐xylene/CuBr/bpy as the initiating system; Second, polystyrene was further used as macroinitiator for the ATRP of octadecyl acrylate to prepare ABA triblock copolymers in the presence of FeCl₂·4H₂O/PPh₃ in toluene. Polymers with controlled molecular weight (M_n = 17,000–23,400) and low polydispersity index value (1.33–1.44) were obtained. The relationship between molecular weight versus conversion showed a straight line. The effect of reaction temperature on polymerization was also investigated, showing a faster polymerization rate under higher temperature. The copolymers were characterized by FTIR, ¹H‐NMR, DSC, and GPC and the crystallization behavior of the copolymers was also studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1539–1545, 2004