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1.
Synthesis of poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers is discussed herein. Siloxane prepolymer was first prepared via acid-catalyzed ring-opening polymerization of octamethylcyclotetrasiloxane (D4) to form polydimethylsiloxane (PDMS) prepolymers. It was subsequently functionalized with hydroxy functional groups at both terminals. The hydroxy-terminated PDMS can readily react with acid-terminated poly(ethylene glycol) (PEG diacid) to give PEG-PDMS block copolymers without using any solvent. The PEG diacid was prepared from hydroxy-terminated PEG through the ring-opening reaction of succinic anhydride. Their chemical structures and molecular weights were characterized using 1H NMR, FTIR and GPC, and thermal properties were determined by DSC. The PEG-PDMS copolymer was incorporated into chitosan in order that PDMS provided surface modification and PEG provided good water swelling properties to chitosan. Critical surface energy and swelling behavior of the modified chitosan as a function of the copolymer compositions and contents were investigated.  相似文献   

2.
N‐trimellitylimido‐L ‐methionine ( 3 ) was prepared by reaction of trimellitic anhydride ( 1 ) with ‐L ‐methionine ( 2 ) in acetic acid solution at refluxing temperature. This diacid was reacted with thionyl chloride, and N‐trimellitylimido‐L ‐methionine diacid chloride ( 4 ) was obtained in quantitative yield. The resulting diacid chloride was reacted with p‐aminobenzoic acid in dry acetone and bis(p‐aminobenzoic acid)‐N‐trimellitylimido‐L ‐methionine ( 5 ) was obtained as a novel optically active amide–imide diacid monomer in high yield. The direct polycondensation of amide–imide diacid monomer 5 with several aromatic diamines was carried out with tosyl chloride (TsCl)/pyridine (Py)/dimetheylformamide (DMF) system. The resulting thermally stable poly(amide–imide)s (PAIs) were obtained in good yields and inherent viscosities ranging between 0.24 and 0.46 dL g?1 and were characterized with FTIR, 1H NMR, CHN, and TGA techniques. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1248–1254, 2007  相似文献   

3.
Poly(p‐dioxanone)–poly(ethylene glycol)–poly(p‐dioxanone) ABA triblock copolymers (PEDO) were synthesized by ring‐opening polymerization from p‐dioxanone using poly(ethylene glycol) (PEG) with different molecular weights as macroinitiators in N2 atmosphere. The copolymer was characterized by 1H NMR spectroscope. The thermal behavior, crystallization, and thermal stability of these copolymers were investigated by differential scanning calorimetry and thermogravimetric measurements. The water absorption of these copolymers was also measured. The results indicated that the content and length of PEG chain have a greater effect on the properties of copolymers. This kind of biodegradable copolymer will find a potential application in biomedical materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1092–1097, 2006  相似文献   

4.
Poly(ethylene glycol) (PEG) segments were introduced into a polyanhydride main chain by copolymerization of terminal-carboxylated poly(ethylene glycol) with diacidic monomers (sebacic acid and trimellitylimidoglycine). IR and 1H NMR spectroscopy confirmed the copolymer structures. DSC analysis showed that these polyanhydrides have low Tg and low crystallinity. In vitro degradation tests indicated that introducing PEG segments accelerated the degradation rate of these polymers and the degradation duration could be manipulated from 3 days to 3 weeks. The pH of the environment caused by the polymer degradation was lower than 5.0; therefore, the polyanhydrides could be used as components of a newly designed pulsed-release device for peptide and protein delivery. © 1999 Society of Chemical Industry  相似文献   

5.
A series of amine‐functionalized block copolymers, poly(caprolactone)‐block‐poly(ethylene glycol) (PCL‐b‐PEG), were synthesized by ring‐opening bulk polymerization (ROP) of ε‐caprolactone (ε‐CL) initiated through the hydroxyl end of the amino poly(ethylene glycol) (PEG) used as a macroinitiator in the presence of stannous 2‐ethylhexonoate [Sn(Oct)2]. The polymerization and end functionality of the polymer were studied by different physicochemical techniques (1H NMR, Fourier transform infrared and X‐ray photoelectron spectroscopy, gel permeation chromatography and thermogravimetric analysis). Thermal, crystalline and mechanical properties of the polymer were thoroughly analyzed using differential scanning calorimetry, wide‐angle X‐ray diffractometry and tensile testing, respectively. The results showed a linear improvement in crystallinity and mechanical properties of the polymer with the content of PEG. Thus the synthesized functional polymers can be used as excellent biomaterials for the delivery of polyanions, as well as macroinitiators for the synthesis of A–B–C‐type block copolymers. Copyright © 2006 Society of Chemical Industry  相似文献   

6.
A series of novel pH- and temperature-responsive multiblock copolymers (poly(PEG/HEP urethane)) consisting of poly(ethylene glycol) (PEG) and poly(amino urethane) (PAU) were synthesized, and their physicochemical properties were studied. The amphiphilic block copolymers were synthesized from PEG, 1,4-bis(hydroxyethyl) piperazine (HEP) and 1,6-diisocyanato hexamethylene (HDI) in the presence of dibutyltin dilaurate as a catalyst. The resulting polymers were examined by FT-IR, 1H and 13C NMR spectroscopies and gel permeation chromatography (GPC). The solution properties of the copolymers were studied by turbidity measurement and fluorescence spectroscopy. The copolymers showed a pH-dependent soluble-insoluble transition in diluted aqueous solutions. The concentrated polymer solutions exhibited a thermo-induced sol-gel-sol phase transition at pH 6.8-7.4. The gel window covers the physiological conditions. After a subcutaneous injection of the multiblock copolymer solution into mice, a transparent and soft gel was formed immediately. The in vitro release of a model anticancer drug, chlorambucil, persisted over 2 weeks under physiological conditions.  相似文献   

7.
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 Tg 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  相似文献   

8.
The synthesis of two low molecular weight linear unsaturated oligoester precursors, poly(propylene fumarate‐co‐sebacate) (PPFS) and poly(ethylene fumarate‐co‐sebacate) (PEFS), are described. PPFS, PEFS, and poly(ethylene glycol) are then used to prepare poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PPFS‐co‐PEG) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PEFS‐co‐PEG) block copolymers. The products thus obtained are investigated in terms of the molecular weight, composition, structure, thermal properties, and solubility behavior. A number of design parameters including the molecular weights of PPFS, PEFS, and PEG, the reaction time in the polymer synthesis, and the weight ratio of PEG to PPFS or to PEFS are varied to assess their effects on the product yield and properties. The hydrolytic degradation of PPFS‐co‐PEG and PEFS‐co‐PEG in an isotonic buffer (pH 7.4, 37°C) is investigated, and it is found that the fumarate ester bond cleaves faster than does the sebacate ester bond. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 295–300, 2004  相似文献   

9.
《Polymer》2007,48(1):139-149
A novel biodegradable triblock copolymer poly(ethylene glycol)-b-poly(l-lactide)-b-poly(l-lysine) (PEG–PLA–PLL) was synthesized by acidolysis of poly(ethylene glycol)-b-poly(l-lactide)-b-poly(ɛ-benzyloxycarbonyl-l-lysine) (PEG–PLA–PZLL) obtained by the ring-opening polymerization (ROP) of ɛ-benzyloxycarbonyl-l-lysine N-carboxyanhydride (ZLys NCA) with amino-terminated PEG–PLA–NH2 as a macroinitiator, and the pendant amino groups of the lysine residues were modified with a peptide known to modulate cellular functions, Gly-Arg-Gly-Asp-Ser-Tyr (GRGDSY, abbreviated as RGD) in the presence of 1,1′-carbonyldiimidazole (CDI). The structures of PEG–PLA–PLL/RGD and its precursors were confirmed by 1H NMR, FT-IR, amino acid analysis and XPS analysis. The cell adhesion and cell spread on the PEG–PLA–PLL/RGD film were enhanced compared to those on pure PLA film. Therefore, the novel RGD-grafted triblock copolymer is promising for cell or tissue engineering applications. Both copolymers PEG–PLA–PZLL and PEG–PLA–PLL showed an amphiphilic nature and could self-assemble into micelles of homogeneous spherical morphology. The micelles were determined by fluorescence technique, dynamic light scattering (DLS), and field emission scanning electron microscopy (ESEM) and could be expected to find application in drug and gene delivery systems.  相似文献   

10.
Poly(adipic anhydride) (PAA) was prepared by the ring‐opening polymerization of adipic anhydride (AA) initiated by potassium poly(ethylene glycol)ate. The effects of various factors, such as the amount of initiator, concentration of the monomer, reaction time and temperature, and polarity of the solvent on the polymerization were investigated. The crude polymerized product was a mixture of PAA homopolymer and poly(ethylene glycol)–poly(adipic anhydride) block copolymer, as confirmed by 1H‐NMR and gel permeation chromatography. Chain‐transfer reactions occurred intensively for the AA polymerization in both the nonpolar solvent toluene and the polar solvents CHCl3 and tetrahydrofuran, which predominantly determined the molecular weight and the monomer conversion for the polymerized product. The lower monomer conversion in toluene was ascribed to a lower livingness for the initiator in the nonpolar solvent when compared with other two, polar solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2194–2201, 2003  相似文献   

11.
A new triptycene‐containing dicarboxylic acid monomer was successfully synthesized by refluxing the diamine, bis(4‐aminophenoxy)phenyl triptycene with trimellitic anhydride in glacial acetic anhydride. A series of novel thermally stable poly(ester‐imide)s were prepared from dicarboxylic acid, bis(4‐trimellitimido phenoxy)phenyl triptycene with various diols by the direct polycondensation. The polymers were obtained in quantitative yields with inherent viscosities of 0.27–0.74 dL g?1. The resulting polymers dissolved in N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, and pyridine. These polymers were fairly stable up to a temperature >450°C and lost 10% weight in the range of 477°C and 575°C in nitrogen. The UV–V is absorption spectra revealed that most of the polymers had absorption maxima around 310 and 341 nm. POLYM. ENG. SCI., 54:2252–2257, 2014. © 2013 Society of Plastics Engineers  相似文献   

12.
A new class of optically active poly(amide‐imide‐urethane) was synthesized via two‐step reactions. In the first step, 4,4′‐methylene‐bis(4‐phenylisocyanate) (MDI) reacts with several poly(ethylene glycols) (PEGs) such as PEG‐400, PEG‐600, PEG‐2000, PEG‐4000, and PEG‐6000 to produce the soft segment parts. On the other hand, 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine‐p‐amidobenzoic acid) (2) was prepared from the reaction of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine) diacid chloride with p‐aminobenzoic acid to produce hard segment part. The chain extension of the above soft segment with the amide‐imide 2 is the second step to give a homologue series of poly(amide‐imide‐urethanes). The resulting polymers with moderate inherent viscosity of 0.29–1.38 dL/g are optically active and thermally stable. All of the above polymers were fully characterized by IR spectroscopy, elemental analyses, and specific rotation. Some structural characterization and physical properties of this new optically active poly(amide‐imide‐urethanes) are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2288–2294, 2004  相似文献   

13.
A novel series of biodegradable copolymers were synthesized by the thermal polycondensation of 3,4-dihydroxycinnamic acid (DHCA) and poly(ethylene glycol) (PEG). The copolymers were characterized by 1H-NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography. It was found that the incorporation of PEG reduced the glass-transition temperature (Tg) of the copolymers, and Tg decreased with increasing amount of PEG in the compositions. The fluorescence spectroscopy revealed that the homopolymer and copolymers of DHCA gave a higher fluorescence emission intensity than that of DHCA monomer, of which the strongest fluorescence emission peak occurred in the copolymers containing a small amount of PEG. X-ray diffraction spectra demonstrated that poly(3,4-dihydroxycinnamic acid) and copolymer were amorphous; this indicated the facile biodegradability of the copolymers. Furthermore, copolymer micelles formed by self-assembly were investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

14.
A new class of optically active poly(amide imide urethane)s (PAIUs) was synthesized via a two-step diisocyanate route. In the first step, 4,4′-methylenebis(phenyl isocyanate) (MDI) was reacted with different diacids to produce an isocyanate-terminated oligo(amide imide). The chain extension of the previous hard segment with poly (ethylene glycol) diols with a molecular weight of 400 was the second step for furnishing a series of new PAIUs. N-Trimellitylimido-L -leucine was used as a diacid monomer for polycondensation reactions. Polymerization reactions were performed without any catalysts or with pyridine or dibutyltin dilaurate as a catalyst. The optimized reaction conditions were used for the reaction of N-trimellitylimido-L -isoleucine, N-trimellitylimido-L -methionine, N-trimellitylimido-S -valine, and N-trimellitylimido-L -phenylalanine as diacid monomers with MDI. The resulting multiblock copolymers had inherent viscosities of 0.25–0.78 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide-type solvents. All these polymers were fully characterized with Fourier transform infrared spectroscopy, 1H-NMR and ultraviolet–visible spectroscopy, specific rotation measurements, and thermal analyses. Some structural characteristics and physical properties of these new optically active PAIUs were examined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

15.
The polymerizations of 1‐(3‐methylphenyl)‐2‐(4‐trimethylsilyl)phenylacetylene ( 1a ) and 1‐(4‐methylphenyl)‐2‐(4‐trimethylsilyl)phenylacetylene ( 1b ) were carried out with TaCl5n‐Bu4Sn to give relatively high‐molecular‐weight polymers ( 2a and 2b ) (Mn > 5 × 105). The obtained polymers were brominated by using benzoyl peroxide and N‐bromosuccinimide first, followed by substitution reaction of three types of polyethylene glycol. When diethylene glycol was used as a reagent on substitution reaction of meta‐substituted polymer, PEG‐functionalized poly(diphenylacetylene) with the highest content of oxyethylene unit [ 4a(2) ] was obtained, and the degree of substitution was 0.60. The degrees of substitution decreased to 0.15 and 0.08 when the polyethylene glycols with higher molecular weights were used. PEG‐substitution reaction to the para‐substituted polymers was difficult to proceed, and hence the degree of substitution was 0.18 even when diethylene glycol was used. The CO2/N2 separation factor of PEG‐functionalized polymer [ 4a(2) ] was as large as 28.8, although that of 2a was 7.41. The other PEG‐functionalized polymers also exhibited high CO2 permselectivity, and their CO2/N2 separation factors were over 20. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

16.
pH and thermo‐responsive graft copolymers are reported where thermo‐responsive poly(N‐isopropylacrylamide) [poly(NIPAAm), poly A ], poly(N‐isopropylacrylamide‐co‐2‐(diethylamino) ethyl methacrylate) [poly(NIPAAm‐co‐DEA), poly B ], and poly(N‐isopropylacrylamide‐co‐methacrylic acid) [poly(NIPAAm‐co‐MAA), poly C ] have been installed to benzaldehyde grafted polyethylene glycol (PEG) back bone following introducing a pH responsive benzoic‐imine bond. All the prepared graft copolymers for PEG‐g‐poly(NIPAAm) [ P‐N1 ], PEG‐g‐poly(NIPAAm‐co‐DEA) [ P‐N2 ], and PEG‐g‐poly(NIPAAm‐co‐MAA) [ P‐N3 ] were characterized by 1H‐NMR to assure the successful synthesis of the expected polymers. Molecular weight of all synthesized polymers was evaluated following gel permeation chromatography. The lower critical solution temperature of graft copolymers varied significantly when grafted to benzaldehyde containing PEG and after further functionalization of copolymer based poly(NIPAAm). The contact angle experiment showed the changes in hydrophilic/hydrophobic behavior when the polymers were exposed to different pH and temperature. Particle size measurement investigation by dynamic light scattering was performed to rectify thermo and pH responsiveness of all prepared polymers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

17.
This study presented the synthesis and characterization of glucosamine (GlcN) modified poly (ethylene glycol) (PEG) hydrogels. The chemical structure was characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The morphology of hydrogels was observed by scanning electron microscopy (SEM). The results indicated that GlcN was successfully incorporated into PEG hydrogel network. Moreover, the data of the swelling ratio showed that the ratio of GlcN‐modified PEG hydrogels was lower than that of pure poly(ethylene glycol) diacrylated (PEGDA). Biocompatibility of unreacted GlcN monomer and GlcN‐modified hydrogels was also evaluated in vitro. Compared with glucosamine hydrochloride, 2 and 5 mM N‐acroloyl‐glucosamine monomer exhibited no toxicity against bone marrow stromal cells (BMSCs), while with the concentration increased to 10 mM, cell viability appeared to decrease. However, when BMSCs were encapsulated in GlcN‐modified hydrogels via photopolymerization method, cells remained vigorous viability. Metabolic activity of the encapsulated cells demonstrated GlcN‐modified hydrogels was favorable for cell proliferation. Compared with free GlcN, covalent binding GlcN showed lower cytotoxicity and higher cell proliferation properties. As a result, GlcN‐modified PEGDA hydrogels could be used as safe and injectable cell carriers for in situ tissue engineering applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

18.
A novel stimuli‐responsive magnetite nanohydrogel (MNHG), namely [poly(ethylene glycol)‐block‐poly(N‐isopropylacrylamide‐co‐maleic anhydride)2]‐graft‐poly(ethylene glycol)/Fe3O4 [PEG‐b‐(PNIPAAm‐co‐PMA)2]‐g‐PEG/Fe3O4, was successfully developed. For this purpose, NIPAAm and MA monomers were block copolymerized onto PEG‐based macroinitiator through atom transfer radical polymerization technique to produce PEG‐b‐(PNIPAAm‐co‐PMA)2. The synthesized Y‐shaped terpolymer was crosslinked through the esterification of maleic anhydride units using PEG chains to afford a hydrogel. Afterward, magnetite nanoparticles were incorporated into the synthesized hydrogel through the physical interactions. The chemical structures of all synthesized samples were characterized using Fourier transform infrared and proton nuclear magnetic resonance spectroscopies. Morphology, thermal stability, size, and magnetic properties of the synthesized MNHG were investigated. In addition, the doxorubicin hydrochloride loading and encapsulation efficiencies as well as stimuli‐responsive drug release ability of the synthesized MNHG were also evaluated. The drug‐loaded MNHG at physiological condition exhibited negligible drug release values. In contrast, at acidic (pH 5.3) condition and a little bit higher temperature (41 °C) the developed MNHG showed higher drug release values, which qualified it for cancer chemotherapy due to especial physiology of cancerous tissue in comparison with the surrounding normal tissue. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46657.  相似文献   

19.
A dicarboxylic acid ( 1 ) bearing two phthalimide rings was prepared by the condensation of N-phenyl-3,3-bis[4-(4-aminophenoxy)phenyl]phthalimidine and trimellitic anhydride. A new family of poly(amide–imide)s having inherent viscosities of 0.65–1.65 dl/g was prepared by the triphenyl phosphite activated polycondensation of the diimide–diacid 1 with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. All the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. The soluble poly(amide–imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range 249–340°C and the 10% weight loss temperatures were above 545°C in nitrogen.  相似文献   

20.
A novel class of wholly aromatic poly(ester‐imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32–0.49 dL g?1 was prepared by the diphenylchlorophosphate‐activated direct polyesterification of the preformed imide‐ring‐containing diacid, 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6‐bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and 1H NMR spectroscopy and elemental analysis. The ultraviolet λmax values of the poly(ester‐imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m‐cresol, as well as in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide‐angle X‐ray diffraction. The resulting poly(ester‐imide)s showed nearly an amorphous nature, except poly(ester‐imide) derived from 4,4′‐dihydroxy biphenyl. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry thermograms were in the range 298–342 °C. The 10% weight loss temperatures (T10%) from thermogravimetric analysis curves were found to be in the range 433–471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry  相似文献   

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