Surface modification of poly(ethylene terephthalate) film by coating with poly(ethylene glycol)‐grafted polystyrene

The poly(ethylene glycol) (PEG)‐grafted styrene (St) copolymer, which was formed as a nanosphere, was used as an agent to modify the surface of poly(ethylene terephthalate) (PET) film. The graft copolymer was dissolved into chloroform and coated onto the PET film by dip–coating method. The coated amount depends on the content ratios of PEG and St, the solution concentration, and the coating cycles. The graft copolymers having a low molecular weight of PEG‐ or St‐rich content was fairly stable on washing in sodium dodecyl sulfate (SDS) aqueous solution. It was confirmed that the PET surface easily altered its surface property by the coating of the graft copolymers. The contact angles of the films coated with the graft copolymers were very high (ca. 105–120°). The coated film has good antistatic electric property, which agreed with PEG content. The best condition of coating is a one‐cycle coating of 1% (w/v) graft copolymer solution. The coated surface had water‐repellency and antistatic electric property at the same time. The graft copolymer consisted of a PEG macromonomer; St was successfully coated onto PET surfaces, and the desirable properties of both of PEG macromonomer and PSt were exhibited as a novel function of the coated PE film. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1524–1530, 1999     

Synthesis and characterization of poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers

Poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. The reaction was carried out under mild conditions, using dicyclohexylcarbodiimide as the coupling agent and dimethylaminopyridine as the catalyst. The resulting copolymers were characterized by various analytical techniques, such as GPC, viscometry, ¹H‐NMR, FTIR, DSC, X‐ray diffractometry, and contact angle measurement. The results indicated that these copolymers presented outstanding properties pertinent to biomedical use, including better miscibility between the two components, low crystallinity, and hydrophilicity. Moreover, the properties of the copolymers can be modulated by adjusting the block length of the two components or the reaction conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1729–1736, 2002; DOI 10.1002/app.10580     

Effect of poly(ethylene glycol) on the solid‐state polymerization of poly(ethylene terephthalate)

Poly(ethylene glycol) (PEG) and end‐capped poly(ethylene glycol) (poly(ethylene glycol) dimethyl ether (PEGDME)) of number average molecular weight 1000 g mol^?1 was melt blended with poly(ethylene terephthalate) (PET) oligomer. NMR, DSC and WAXS techniques characterized the structure and morphology of the blends. Both these samples show reduction in T_g and similar crystallization behavior. Solid‐state polymerization (SSP) was performed on these blend samples using Sb₂O₃ as catalyst under reduced pressure at temperatures below the melting point of the samples. Inherent viscosity data indicate that for the blend sample with PEG there is enhancement of SSP rate, while for the sample with PEGDME the SSP rate is suppressed. NMR data showed that PEG is incorporated into the PET chain, while PEGDME does not react with PET. Copyright © 2005 Society of Chemical Industry     

Strong resistance of poly (ethylene glycol) based L‐tyrosine polyurethanes to protein adsorption and cell adhesion

Biofouling that involves protein adsorption, cell and bacteria adhesion, and biofilm formation between a surface and biological entities is a great challenge for biomedical and industry applications. In this work, L ‐tyrosine‐derived polyurethanes (L ‐polyurethane) with different molecular weights of poly(ethylene glycol) (PEG) were synthesized, characterized and coated on gold surfaces using spin‐coating. The non‐fouling activity of different L ‐polyurethane films was evaluated by protein adsorption and cell adhesion. Surface plasmon resonance and cell assay results demonstrate that the PEG content in these L ‐polyurethanes contributes excellent resistance to protein adsorption and cell attachments. This work provides alternative and effective biomaterials for potential applications in blood‐contacting devices. Copyright © 2011 Society of Chemical Industry     

Comparison of micelles formed by amphiphilic poly(ethylene glycol)‐b‐poly(trimethylene carbonate) star block copolymers

In this article, we describe the synthesis and solution properties of PEG‐b‐PTMC star block copolymers via ring‐opening polymerization (ROP) of trimethylene carbonate (TMC) monomer initiated at the hydroxyl end group of the core PEG using HCl Et₂O as a monomer activator. The ROP of TMC was performed to synthesize PEG‐b‐PTMC star block copolymers with one, two, four, and eight arms. The PEG‐b‐PTMC star block copolymers with same ratio of between hydrophobic PTMC and hydrophilic PEG segments were obtained in quantitative yield and exhibited monomodal GPC curves. The amphiphilic PEG‐b‐PTMC star block copolymers formed spherical micelles with a core–shell structure in an aqueous phase. The mean hydrodynamic diameters of the micelles increased from 17 to 194 nm with increasing arm number. As arm number increased, the critical micelle concentration (CMC) of the PEG‐b‐PTMC star block copolymers increased from 3.1 × 10^?3 to 21.1 × 10^?3 mg/mL but the partition equilibrium constant, which is an indicator of the hydrophobicity of the micelles of the PEG‐b‐PTMC star block copolymers in aqueous media, decreased from 4.44 × 10⁴ to 1.34 × 10⁴. In conclusion, we confirmed that the PEG‐b‐PTMC star block copolymers form micelles and, hence, may be potential hydrophobic drug delivery vehicles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Biodegradability of poly(ethylene terephthalate) copolymers with poly(ethylene glycol)s and poly(tetramethylene glycol)

Poly(ethylene terephthalate) copolymers were prepared by melt polycondensation of dimethyl terephthalate and excess ethylene glycol with 10–40mol% (in feed) of poly(ethylene glycol) (E) and poly(tetramethylene glycol) (B), with molecular weight (MW) of E and B 200–7500 and 1000, respectively. The reduced specific viscosity of copolymers increased with increasing MW and content of polyglycol comonomer. The temperature of melting (T_m), cold crystallization and glass transition (T_g) decreased with the copolymerization. T_m depression of copolymers suggested that the E series copolymers are the block type at higher content of the comonomer. T_g was decreased below room temperature by the copolymerization, which affected the crystallinity and the density of copolymer films. Water absorption increased with increasing content of comonomer, and the increase was much higher for E1000 series films than B1000 series films. The biodegradability was estimated by weight loss of copolymer films in buffer solution with and without a lipase at 37°C. The weight loss was enhanced a little by the presence of a lipase, and increased abruptly at higher comonomer content, which was correlated to the water absorption and the concentration of ester linkages between PET and PEG segments. The weight loss of B series films was much lower than that of E series films. The abrupt increase of the weight loss by alkaline hydrolysis is almost consistent with that by biodegradation.     

Mechanical properties and morphology of poly(ethylene glycol)‐side‐chain‐modified bismaleimide polymer

Two maleimido‐end‐capped poly(ethylene glycol) (m‐PEG)‐modified bismaleimide (BMI) resins [4,4′‐bismaleimido diphenylmethane (BDM)] were synthesized from poly(ethylene glycol) (PEG) of two different molecular weights. A series of m‐PEGs and unmodified BDM were blended and thermally cured. The effect of incorporating m‐PEG side chains on the morphology and mechanical behaviors of BMI polymer were evaluated. The mechanical properties of these m‐PEG‐modified BMIs that were evaluated included flexural modulus, flexural strength, strain at break, fracture toughness, and fracture energy. The morphology of these blends was studied with scanning electron microscopy. All the m‐PEG‐modified BMI polymers showed various degrees of phase separation depending on the molecular weights and concentrations of the m‐PEG used. The effects of these morphological changes in the m‐PEG‐modified BMI polymers were reflected by the improved fracture toughness and strain at break. However, there was a reduction in the flexural moduli in all m‐PEG‐modified BMI polymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 715–724, 2002     

Synthesis and characterization of novel block copolymer from trans‐4‐hydroxy‐L‐proline and poly(ethylene glycol)

A series of novel ABA‐type block copolymers were synthesized by polymerization of trans‐4‐hydroxy‐L ‐proline (HyP) in the presence of various molecular weight poly(ethylene glycol)s (PEGs), a bifunctional OH‐terminated PEG using stannous octoate as catalyst. The optimal reaction conditions for the synthesis of the copolymers were obtained with 5 wt % stannous octoate at 140°C under vacuum (20 mmHg) for 24 h. The synthesized copolymers were characterized by IR spectroohotometry, proton nuclear magnetic resonance, differential scanning calorimetry, and Ubbelohde viscometer. The glass transition temperature (T_g) of the copolymers shifted to significantly higher temperature with increasing the number average degree of polymerization and HyP/PEO molar ratio. In contrast, the melting temperature (T_m) decreased with increasing the HyP/PEO molar ratio. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1581–1587, 2001     

Enhanced dynamic mechanical and shape‐memory properties of a poly(ethylene terephthalate)–poly(ethylene glycol) copolymer crosslinked by maleic anhydride

Dimethyl terephthalate (DMT) and ethylene glycol (EG) were used for the preparation of poly(ethylene terephthalate) (PET), and poly(ethylene glycol) (PEG) was added as a soft segment to prepare a PET–PEG copolymer with a shape‐memory function. MWs of the PEG used were 200, 400, 600, and 1000 g/mol, and various molar ratios of EG and PEG were tried. Their tensile and shape‐memory properties were compared at various points. The glass‐transition and melting temperatures of PET–PEG copolymers decreased with increasing PEG molecular weight and content. A tensile test showed that the most ideal mechanical properties were obtained when the molar ratio of EG and PEG was set to 80:20 with 200 g/mol of PEG. The shape memory of the copolymer with maleic anhydride (MAH) as a crosslinking agent was also tested in terms of shape retention and shape recovery rate. The amount of MAH added was between 0.5 and 2.5 mol % with respect to DMT, and tensile properties and shape retention and recovery rate generally improved with increasing MAH. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 27–37, 2002     

Drug release from poly(ortho esters)–poly(ethylene glycol) polyblend

A polyblend of poly(ortho esters)–poly(ethylene glycol) (POE–PEG) was prepared. The release behavior of the acetanilide‐loaded film of the POE–PEG polyblend was studied. Blending POE with water‐soluble PEG can promote the release of drug in pH 7.4 PBS buffer at 37°C, while POE has plasticizing effect on PEG. Infrared and X‐ray diffraction studies reveal that there is some interaction between POE and acetanilide. The SEM micrographs disclose that the porosity of the drug‐loaded film enhances with an increase immersing time. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 303–309, 1999     

Synthesis and hydrophilicity of poly(butylene 2,6‐naphthalate)/poly(ethylene glycol) copolymers

Poly(butylene 2,6‐naphthalate) (PBN)/poly(ethylene glycol) (PEG) copolymers were synthesized by the two‐step melt copolymerization process of dimethyl‐2,6‐naphthalenedicarboxylate (2,6‐NDC) with 1,4‐butanediol (BD) and PEG. The copolymers produced had different PEG molecular weights and contents. The structures, thermal properties, and hydrophilicities of these copolymers were studied by ¹H NMR, DSC, TGA, and by contact angle and moisture content measurements. In particular, the intrinsic viscosities of PBN/PEG copolymers increased with increasing PEG molecular weights, but the melting temperatures (T_m)_, the cold crystallization temperatures (T_cc)_, and the heat of fusion (ΔH_f) values of PBN/PEG copolymers decreased on increasing PEG contents or molecular weights. The thermal stabilities of the copolymers were unaffected by PEG content or molecular weight. Hydrophilicities as determined by contact angle and moisture content measurements were found to be significantly increased on increasing PEG contents and molecular weights. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2677–2683, 2006     

Crystallization and morphology of cholesterol end‐capped poly(ethylene glycol)

Crystallization and morphology of polyethylene glycol with molecular weight M_n = 2000 (PEG2000) capped with cholesterol at one end (CS‐PEG2000) and at both ends (CS‐PEG2000‐CS) were investigated. It is found that the bulky cholesteryl end group can retard crystallization rate and decrease crystallinity of PEG, especially for CS‐PEG2000‐CS. Isothermal crystallization kinetics shows that the Avrami exponent of CS‐PEG2000 decreases as crystallization temperature (T_c). The Avrami exponent of CS‐PEG2000‐CS increases slightly with T_c, but it is lower than that of CS‐PEG2000. Compared to the perfect spherulite morphology of PEG2000, CS‐PEG2000 exhibits irregular and leaf‐like spherulite morphology, while only needle‐like crystals are observed in CS‐PEG2000‐CS. The linear growth rate of CS‐PEG2000 shows a stronger dependence on T_c than PEG2000. The cholesterol end group alters not only the free energy of the folding surface, but also the temperature range of crystallization regime. The small angle X‐ray scattering (SAXS) results show that lamellar structures are formed in all these three samples. By comparing the long periods obtained from SAXS with the theoretically calculated values, we find that the PEG chains are extended in PEG2000 and CS‐PEG2000, but they are once‐folded in CS‐PEG2000‐CS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2464–2471, 2007     

Poly(ethylene glycol)‐modulated cellular biocompatibility of polyhydroxyalkanoate films

Polyhydroxybutyrate (PHB) and its copolymer with hydroxyvalerate, P(HB‐co‐HV), are widely used biomaterials. In this study, improvements of their biological properties of degradability and compatibility were achieved by blending with low‐molecular‐weight poly(ethylene glycol) (PEG106) approved for medical use. Surface morphology and chemistry are known to support cell attachment. Attachment and proliferation of neural olfactory ensheathing cells increased by 17.0 and 32.2% for PHB and P(HB‐co‐HV) composite films. Cell attachment was facilitated by increases in surface hydrophilicity, water contact angles decreased by 26 ± 2° and water uptake increased by 23.3% depending upon biopolymer and PEG loading. Cells maintained high viability (>95%) on the composite films with no evidence of cytotoxic effects. Assays of mitochondrial function and cell leakage showed improved cell health as a consequence of PEG loading. The PEG component was readily solubilised from composite films, allowing control of degradation profiles in the cell growth medium. Promotion of biopolymer compatibility and degradability was not at the expense of material properties, with the extension to break of the composites increasing by 5.83 ± 1.06%. Similarly, crystallinity decreased by 36%. The results show that blending of common polyhydroxyalkanoate biomaterials with low‐molecular‐weight PEG can be used to promote biocompatibility and manipulate physiochemical and material properties as well as degradation.© 2013 Society of Chemical Industry     

Synthesis and characterization of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) block copolymers prepared by a salicylaldimine‐aluminum complex

A series of poly(?‐caprolactone)‐b‐poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights were synthesized with a salicylaldimine‐aluminum complex in the presence of monomethoxy poly(ethylene glycol). The block copolymers were characterized by ¹H NMR, GPC, WAXD, and DSC. The ¹H NMR and GPC results verify the block structure and narrow molecular weight distribution of the block copolymers. WAXD and DSC results show that crystallization behavior of the block copolymers varies with the composition. When the PCL block is extremely short, only the PEG block is crystallizable. With further increase in the length of the PCL block, both blocks can crystallize. The PCL crystallizes prior to the PEG block and has a stronger suppression effect on crystallization of the PEG block, while the PEG block only exerts a relatively weak adverse effect on crystallization of the PCL block. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Porous poly(ethylene glycol)–polyurethane hydrogels as potential biomaterials

We report the synthesis of porous poly(ethylene glycol)–polyurethane (PEG‐PU) hydrogels using PEG‐4000 as a soft segment and 4,4′‐methylenebis(cyclohexylisocyanate) as a hard segment. The degree of swelling in the hydrogels could be controlled by varying the amount of crosslinking agent, namely 1,2,6‐hexanetriol. Structural characterization of the hydrogels was performed using solid‐state ¹³C NMR and Fourier transform infrared spectroscopy. Wide‐angle X‐ray diffraction studies revealed the existence of crystalline domains of PEG and small‐angle X‐ray scattering studies showed the presence of lamellar microstructures. For generating a porous structure in the hydrogels, cryogenic treatment with lyophilization was used. Scanning electron microscopy and three‐dimensional micro‐computed tomography imaging of the hydrogels indicated the presence of interconnected pores. The mechanical strength of the hydrogels and xerogels was measured using dynamic mechanical analysis. The observed dynamic storage moduli (E′) for the equilibrium swollen and dry gels were found to be 0.15 and 4.2 MPa, respectively. Interestingly, the porous PEG‐PU xerogel also showed E′ of 5.6 MPa indicating a similar mechanical strength upon incorporating porosity into the gel matrix. Finally, preliminary cytocompatibility studies showed the ability of cells to proliferate in the hydrogels. These gels show promise for applications as scaffolds and implants in tissue engineering. © 2014 Society of Chemical Industry     

Synthesis of amphiphilic poly(phthalazinone ether sulfone ketone)‐graft‐poly(ethylene glycol) graft copolymers via Williamson etherification

Amphiphilic graft copolymers consisting of poly(phthalazinone ether sulfone ketone) (PPESK) backbones and poly(ethylene glycol) (PEG) side chains were synthesized via reaction of chloromethylated PPESK (CMPPESK) with a sodium alkoxide of methoxyl PEG (PEG‐ ONa). The reactive precursor, CMPPESK, was prepared by the chloromethylation of PPESK with chloromethylether (CME) using concentrated H₂SO₄ as reaction medium. FTIR spectroscopy, ¹H‐NMR and Solid‐state ¹³C CP‐MAS NMR analysis confirmed the covalent linking of PEG with PPESK backbones. The PEG content in the graft copolymers from ¹H‐NMR analysis varied from 21.0 to 37.2 wt %, which was approximately in agreement with that calculated from TGA tests. The graft products have good solubility in many aprotic polar solvents and can be slightly swelled by water and ethanol, but water insoluble. Contact angle measurements revealed that the hydrophilicity of PPESK was significantly improved by the introduction of PEG graft chains, indicating the graft copolymer is a potential hydrophilic additive for PPESK membranes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007.     

异端基遥爪聚乙二醇的合成

采用3种新式引发剂,即2-(苄氧基）乙醇钾、2-(四氢-2H-吡喃-2-氧基)乙醇钾、单丙烯基乙二醇钾引发环氧乙烷阴离子开环聚合,反应条件为25 ℃、48 h、醇与萘钾摩尔比例1∶1,得到3种异端基遥爪聚乙二醇。以2-(苄氧基）乙醇钾引发聚合所得产物为起始物,经一系列反应,得到两种两端均为活性基团的异端基遥爪聚乙二醇,这种方法具有普适性。通过1HNMR及GPC手段,表征了产物的结构、分子量及分子量分布。结果表明可以得到高产率、分子量可控且分布窄的异端基遥爪聚乙二醇。     

Miscibility of polystyrene with poly(ethylene oxide) and poly(ethylene glycol)

The intrinsic viscosity of polystyrene–poly(ethylene oxide) (PS–PEO) and PS–poly(ethylene glycol) (PEG) blends have been measured in benzene as a function of blend composition for various molecular weights of PEO and PEG at 303.15 K. The compatibility of polymer pairs in solution were determined on the basis of the interaction parameter term, Δb, and the difference between the experimental and theoretical weight-average intrinsic viscosities of the two polymers, Δ[η]. The theoretical weight-average intrinsic viscosities were calculated by interpolation of the individual intrinsic viscosities of the blend components. The compatibility data based on [η] determined by a single specific viscosity measurement, as a quick method for the determination of the intrinsic viscosity, were compared with that obtained from [η] determined via the Huggins equation. The effect of molecular weights of the blend components and the polymer structure on the extent of compatibility was studied. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1471–1482, 1998     

聚乙二醇/聚己内酯三嵌段共聚物的合成与表征

以甲苯二异氰酸酯 (TDI)为偶联剂 ,合成了聚乙二醇 (PEG) /聚己内酯 (PCL)两亲性三嵌段共聚物 (PEG-b-PCL -b -PEG ,PECL) ,采用IR、1 H-NMR、DSC和WAXD分析和研究了PECL的结构与性能。实验结果表明 ,PECL的结构和组成与设计相一致 ,结晶度和熔点均低于均聚物 ,且随着PECL中PCL嵌段含量的增加 ,PCL嵌段熔点升高。透射电镜照片显示PECL纳米粒呈核 /壳结构的球形。