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1.
A series of biodegradable random unsaturated/saturated poly(ether ester amide)s copolymers (USPEEAs) were synthesized by an active solution polycondensation of unsaturated and saturated dicarboxylic acid‐based diester monomers with diamine salts of phenylalanine and saturated oligo(ethylene glycol) (OEG). These USPEEA copolymers were obtained with fairly good yields in DMA solvent. The chemical structures of the USPEEA copolymers were confirmed by both IR and NMR spectra. The molecular weights (Mn and Mw) of USPEEAs measured by GPC ranged from 3 to 27 kg/mol with the molecular weight distribution (MWD) ranging from 1.52 to 2.13. USPEEA copolymers obtained had Tg lower than that of the pure UPEEAs but higher than that of pure saturated poly(ether ester amide)s (SPEEA). An increase in the unsaturated component in USPEEAs led to an increase in their Tg. A preliminary in vitro biodegradation property of USPEEA copolymers were investigated in both pure PBS buffer and α‐chymotrypsin solutions. The USPEEA copolymers showed a pronounced weight loss in enzyme solutions, but a smaller weight loss in a pure PBS. The biodegradation rates of USPEEA copolymers in α‐chymotrypsin solution were much slower than those of pure PEEAs. Therefore, upon adjusting monomers feed ratio, USPEEA copolymers could have controlled chemical, physical, and biodegradation properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

2.
This study examines the isothermal treatment of poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) powders and films. The PHB and PHBV crystallinities were determined using X‐ray diffractometry, and shown to increase with temperature (130–150°C) and then decreased from 55% to 45% at 180°C. The crystal morphology of crystal planes (101) and (111) became sharp at a high temperature. The weight average molecular weight (Mw) of PHB decreased from 1,028,000 to 41,800 g/mol when heated at 180°C for 30 min. The molecular weight of PHB decreased more rapidly than that of PHBV with time. No peak signal was observed in gel permeation chromatography after heating at 150°C because the solubility of PHB changed with crystallinity. The thermal behaviors of PHB and PHBV were analyzed by differential scanning calorimetry and thermogravimetric analysis. The roughness, contact angle, and surface morphology of PHB and PHBV films were also measured to determine the surface properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3659–3667, 2013  相似文献   

3.
Propolis is a complex mixture of phytochemicals, with antibacterial, anti-inflammatory, and healing properties. All-trans retinoic acid is implicated in wound healing by stimulating angiogenesis, cell recruitment, extracellular matrix deposition, and reepithelization. The incorporation of both agents to a polymeric wound dressing composed of poly (vinyl alcohol) and sodium alginate may result in improved healing allied to controlled release, fluid uptake, and wound protection. In the present work, we have physically characterized this wound dressing and analyzed its release kinetics. The anti-inflammatory capacity was assayed. SEM images showed a highly porous structure with a diverse morphology. FTIR spectra displayed a highly cross-linked structure with both polymers connected by hydrogen bonds and acetal bridges. The wound dressings were able to retain great volumes of PBS. Propolis and vitamin A releasing behavior were maintained for 6 h. The concentrations of the biologically active substances were capable of promoting anti-inflammatory action in an erythrocyte membrane stabilization model. The wound dressings obtained here showed adequate physical properties. The fabrication process did not affect the anti-inflammatory capacity. Further tests are needed to ensure the biocompatibility and to assess other biological activities of the therapeutic agents.  相似文献   

4.
Scaffolds of a biodegradable poly(ester amide) constituted of L ‐alanine, sebacic acid, and 1,12‐dodecanediol units (abbreviated as PADAS) were prepared by the compression‐molding/particulate‐leaching method. The influence of the type, size, and percentage of salt on the scaffold porosity and morphology was evaluated. The thermal behavior and crystallinity were also studied for samples obtained under different processing conditions. PADAS scaffolds were not cytotoxic because they showed good cell viability and supported cell growth at a similar ratio to that observed for the biocompatible materials used as a reference. The use of PADAS scaffolds as a drug‐delivery system was also evaluated by the employment of ibuprofen, a drug with well known anti‐inflammatory effects. Different drug‐loading methods were considered, and their influence on the release in a Sörensen's medium was evaluated as well as the influence of the scaffold morphology. A sustained release of ibuprofen could be attained without the production of a negative effect on the cell viability. The release kinetics of samples loaded before melt processing was well described by the combined Higuchi/first‐order model. This allowed the estimation of the diffusion coefficients, which ranged between 3 × 10?14 and 5 × 10?13 m2/s. Samples loaded by immersion in ibuprofen solutions showed a rapid release that could be delayed by the addition of polycaprolactone to the immersion medium (i.e., the release rate decreased from 0.027 to 0.015 h?1). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.  相似文献   

5.
The purpose of this study was to evaluate the in vitro characteristics of poly(lactic acid‐co‐lysine) arginine–glycine–aspartic acid (PLA–PLL–RGD) nanoparticles (NPs) loaded with mitoxantrone. PLA–PLL–RGD NPs with a particle size of 200 nm were prepared with a modified emulsification solvent‐diffusion method. The encapsulation efficiency of the mitoxantrone‐loaded NPs was 85%. In vitro release experiments showed that the release of the drug was prolonged and sustained, and approximately 60.2% of the mitoxantrone was released in the first week. The released drug was integrated to achieve desired drug‐release profiles and still possessed bioactivity according to a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2h‐tetrazolium bromide assay, which indicated that mitoxantrone‐loaded NPs were more cytotoxic against Michigan Cancer Foundation 7 (MCF‐7) breast cancer cells than mitoxantrone. Furthermore, the association processes of NPs with MCF‐7 cells, including binding and effective internalization, were investigated in vitro. The cellular uptake of the NPs was qualitatively studied with confocal laser scanning microscopy and was confirmed with flow cytometry analysis. These experimental results indicated that PLA–PLL–RGD NPs could be used as drug carriers for mitoxantrone. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

6.
The sterically hindered amine monomer 4‐[3‐triethoxysilylpropoxyl]‐2,2,6,6‐tetramethylpiperidine has been synthesized and covalently bonded to the surfaces of silica gel particles and cellulose (cotton) and copolymerized in a polyurethane coating formulation. Upon exposure to dilute sodium hypochlorite (household bleach), a very stable N‐Cl bond is formed in situ at the hindered amine nitrogen site. This source of oxidative chlorine provides an antimicrobial function to the silica gel, cotton, and polyurethane. Stability, regenerability, and biocidal efficacy data are presented. The new N‐halamine materials were remarkably effective against Staphylococcus aureus and Escherichia coli O157 : H7 in brief periods of contact. The materials should find application in water treatment and medical applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

7.
Biodegradable poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and PLA/PBAT/Al2O3 nanocomposites were fabricated via solution blending. The influence of PBAT and Al2O3 content on the thermal stability, flexural properties, impact strength, and morphology of both the PLA/PBAT blends and the PLA/PBAT/Al2O3 nanocomposites were investigated. The impact strength of the PLA/PBAT/Al2O3 nanocomposites containing 5 wt% PBAT increased from 4.3 to 5.2 kJ/m2 when the Al2O3 content increased from 0 to 1 wt%. This represents a 62% increase compared to the impact strength of pristine PLA and a 20% increase compared to the impact strength of PLA/PBAT blends containing 5 wt% PBAT. Scanning electron microscopy imaging revealed that the Al2O3 nanoparticles in the PLA/PBAT/Al2O3 nanocomposites function as a compatibilizer to improve the interfacial interaction between the PBAT and the PLA matrix.  相似文献   

8.
Leachable‐free radiopaque iodinated polymers were designed as long‐lived embolization materials visible by X‐ray tomography. This is a definite improvement over liquid embolics incorporating either radiopaque inorganic particles or iodinated polymers having hydrolysable ester bonds. Grafting 4‐iodobenzyl or 2,3,5‐triiodobenzyl groups to poly(vinyl alcohol) (PVAL) yields iodobenzyl ethers of PVAL having iodine contents in the range 40–70 wt %. Their solubility in solvents accepted for medical devices (DMSO and NMP), viscosity of concentrated solutions, precipitation behavior, radiopacity, and stability with respect to sterilization and hydrolysis were assessed. The solvent NMP allows the preparation of concentrated solutions of suitable viscosity for their application as liquid embolics. Precipitation in water yields a cohesive mass of material that can plug vascular malformations. A rationale to the properties is given in terms of the Hansen contributions to the Hildebrand solubility parameters. Iodobenzyl ethers of PVA resist hydrolysis whereas their corresponding iodobenzoyl esters leach iodinated fragments. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41791.  相似文献   

9.
Hydrogels are a promising candidate for applications in biomedicine and bioengineering, but their mechanical properties often restrict their applications. To improve the mechanical performance of poly(vinyl alcohol) (PVA) hydrogels, we introduced sodium carboxymethylcellulose (CMC), and graphene oxide (GO) into them. We prepared a series of composite hydrogels composed of PVA, CMC, and GO with epichlorohydrin as a chemical crosslinker. We used Fourier transform infrared spectroscopy and X-ray diffraction to characterize the chemical structures of GO and the hydrogel. The dynamic mechanical analysis results show the synergistic enhancement effects of CMC and GO on the PVA hydrogel. The swelling process of the hydrogels also fit well with the second-order kinetic equation. Scanning electron microscopy results suggest that the neat mesh structure facilitated superior mechanical properties in the hydrogels. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47644.  相似文献   

10.
Supramolecular poly(?‐capolactone)/poly(lactide) alternating multiblock copolymers were prepared by UPy‐functionalized poly(lactide)‐b‐ poly(?‐capolactone)‐b‐ poly(lactide) copolymers. The prepared supramolecular polymers (SMPs) exhibit the characteristic properties of thermoplastic elastomers. The stereo multiblock SMPs (sc‐SMPs) were formed by blending UPy‐functionalized poly(l ‐lactide)‐b‐ PCL‐b‐ poly(l ‐lactide) (l ‐SMPs) and UPy‐functionalized poly(d ‐lactide)‐b‐ PCL‐b‐ poly(d ‐lactide) (d ‐SMPs) due to stereocomplexation of the PLLA and PDLA blocks. Sc‐SMPs with low content of d ‐SMPs (≤20%) are transparent, elastic solids, while those having high d ‐SMPs content are opaque, brittle solids. The effects of l ‐SMPs/d ‐SMPs mixing ratios on thermal, crystallization behaviors, crystal structure, mechanical and hydrophilic properties of sc‐SMPs were deeply investigated. The incorporation of UPy groups depresses the crystallization of polymer, and the stereocomplex formation accelerates the crystallization rate. The used initiator functionalized polyhedral oligomeric silsesquioxanes causes a different effect on the crystallization of PLA and PCL blocks. The tensile strength and elongation at break of l d /d d ‐SMPs (d represents the initiator diethylene glycol) are significantly larger than that of l p /d p ‐SMPs (p represents the initiator polyhedral oligomeric silsesquioxanes), and their heat resistance and hydrophilicity can be also modulated by the l ‐SMPs/d ‐SMPs mixing ratios and the different initiators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45575.  相似文献   

11.
Poly(lactic acid) (PLA) is a biobased polymer made from biomass having high mechanical properties for engineering materials applications. However, PLA has certain limited properties such as its brittleness and low heat distortion temperature. Thus, the aim of this study is to improve toughness of PLA by blending with poly(butylene succinate‐co‐adipate) (PBSA), the biodegradable polymer having high toughness. Polymer blends of PLA and PBSA were prepared using a twin screw extruder. The melt rheology and the thermal property of the blends were examined. Further the blends were fabricated into compression molded parts and melt‐spun fiber and were subjected to tensile and impact tests. When the PBSA content was low, PBSA phase was finely dispersed in the PLA matrix. On the other hand, when the PBSA content was high, this minor phase dispersed as a large droplet. Mechanical properties of the compression molded parts were affected by the dispersion state of PBSA minor component in PLA matrix. Impact strength of the compression molded parts was also improved by the addition of soft PBSA. The improvement was pronounced when the PBSA phase was finely dispersed in PLA matrix. However, the mechanical property of the blend fibers was affected by the postdrawing condition as well as the PBSA content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41856.  相似文献   

12.
A novel pH‐sensitive hydrogel system composed of itaconic acid (IA) and N‐[3‐(dimethylamino) propyl] methacrylamide was designed. This system was prepared by aqueous copolymerization with N,N‐methylene bisacrylamide as a chemical crosslinker. The chemical structure of the hydrogels was characterized by Fourier transform infrared (FTIR) spectroscopy. The microstructure and morphology of the hydrogels were evaluated by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The SEM study of hydrogels on higher magnification revealed a highly porous morphology with uniformly arranged pores ranging from 40 to 200 μm in size. XRD analysis revealed the amorphous nature of the hydrogels, and it was found that an increase in the IA content in the monomer feed greatly reduced the crystallinity of the hydrogels. Swelling experiments were carried out in buffer solutions at different pH values (1.2–10) at 37°C ± 1°C to investigate their pH‐dependent swelling behavior and dimensional stability. An increase in the acid part (IA) increased the swelling ratio of the hydrogels. Temperature‐sensitive swelling of the hydrogels was investigated at 20–70°C in simulated intestinal fluid. The hydrogels swelled at higher temperatures and shrank at lower temperatures. 5‐Aminosalicylic acid (5‐ASA) was selected as a model drug, and release experiments were carried out under simulated intestinal and gastric conditions. 5‐ASA release from the poly N‐[3‐(dimethylamino) propyl] methacrylamide‐co‐itaconic acid‐80 (PDMAPMAIA‐80) hydrogel was found to follow non‐Fickian diffusion mechanism under gastric conditions, and a super case II transport mechanism was found under intestinal conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

13.
A new family of biodegradable amino acid-based poly(ether ester amide)s (AA-PEEAs) consisting of three building blocks [poly(ε-caprolactone) (PCL), L -phenylalanine (Phe), and aliphatic acid dichloride] were synthesized by a solution polycondensation. Using DMA as the solvent, these PCL-containing Phe-PEEA polymers were obtained with fair to very good yields with weight average molecular weight (Mw) ranging from 6.9 kg/mol to 31.0 kg/mol, depending on the original molecular weight of PCL. The chemical structures of the PCL-containing Phe-PEEA polymers were confirmed by IR and NMR spectra. These PCL-containing Phe-PEEAs had lower Tg than most of the oligoethylene glycol (OEG) based AA-PEEAs due to the more molecular flexibility of the PCL block in the backbones, but had higher Tg than non-amino acid based PEEA. The solubility of the PCL-containing Phe-PEEA polymers in a wide range of common organic solvents, such as THF and chloroform, was significantly improved when comparing with aliphatic diol based poly(ester amide)s and OEG based AA-PEEAs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

14.
A new family of positively charged and water soluble amino acid‐based poly(ester amide)s (PEAs) consisting of nontoxic L ‐arginine, diols, and aliphatic dicarboxylic acids building blocks was synthesized and characterized. The L ‐arginine based PEAs (Arg‐PEAs) were prepared by a solution polycondensation of two monomers: tetra‐p‐toluenesulfonic acids salts or hydrochloride acid salts of bis‐(L ‐arginine) α, ω‐alkylene diesters (monomer II ), and di‐p‐nitrophenyl esters of saturated or unsaturated dicarboxylic acids (monomer I ). Optimal reaction conditions were studied as functions of type of solvents and acid acceptors, concentrations of reactants. The molecular weights (Mn and Mw) of Arg‐PEAs measured by GPC ranged from 20,000 to 60,000 g mol?1 with a rather narrow molecular weight distribution below 1.5. The chemical structures were confirmed by IR and NMR spectra. Arg‐PEAs obtained were all amorphous materials with Tg from 33 to 125°C, depending on the number and the type (saturated vs. unsaturated) of methylene groups in diols or diacids, and the type of counter‐ions attached to the guanidine group of the Arg‐based PEAs. The Arg‐PEAs had a high solubility in all polar solvents, including water. Preliminary studies of cell morphology and DNA capture capability of Arg‐PEAs indicated that this new family of cationic PEAs was nontoxic and more biocompatible than a commercial transfection agent (Superfect®), and can successfully capture plasma DNA. The strong positive charge of Arg‐PEAs as well as their good water solubility could provide unique characteristics for potential gene transfection or other charge preferred biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

15.
Dry eye syndrome is an ocular tear deficiency disorder that affects millions of people in the United States. It has been recognized as a significant lifestyle issue and is among the most frequently established diagnoses in ophthalmology. Tear substitutes (or artificial tear formulations) are the mainstay of dry eye therapy. While many commercial products are available, their efficacy is limited because of their short retention time in the eye, and/or low patient acceptance. In this study, our objectives were to obtain water soluble products with opened glucose rings along the starch backbone, and tear substitute formulations based on these products with strengthened mucoadhesion, shear thinning behavior, improved tear film stability, and no irritancy to the eye. To this end we have synthesized a series of starch based copolymers, DiHydroxyl Starches (DHS). This modification of starch is not a new science, but the application of these polymers to tear substitutes is novel. These polymers were characterized as ocular lubricants utilizing both in vitro and in vivo testing. Specifically, mucoadhesion and rheological behavior were examined. Their performance as ocular lubricants was evaluated utilizing the tear‐film break up times of rabbits before and after application of the copolymers. In addition, the effect of autoclaving and ocular toxicity were tested. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

16.
17.
A complex of chitosan (CS‐40) and nisin (CS‐40/nisin) was prepared and characterized with Fourier transform infrared spectroscopy and thermal analysis (thermogravimetry, differential thermogravimetry, and differential scanning calorimetry). The results show that the complex formed mainly by electrostatic interaction between the protonated amino group in CS‐40 backbone with the carboxylate ion of nisin. Minimum inhibitory concentrations (MICs) were evaluated against Gram‐positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Bacillus stearothermophilus), Gram‐negative bacteria (Escherichia coli, Salmonella enteritidis, and Proteus vulgaris), and fungi (Fusarium oxysporum). The results show that the CS‐40/nisin solution did inhibit or even more strongly inhibited the growth of all the tested microorganisms, whereas CS‐40 did not inhibit the growth of F. oxysporum and nisin did not inhibit the growth of Gram‐negative bacteria (E. coli, S. enteritidis, and P. vulgaris). The relative inhibition times of CS‐40/nisin solutions with different concentrations and ratios of CS‐40 and nisin were also investigated against the seven microorganisms. The results showed that CS‐40/nisin solutions with CS‐40/nisin concentration ratios of 0.05/0.005, 0.05/0.0025, 0.05/0.00125, and 0.025/0.0001% had higher antimicrobial activity against all tested bacteria and fungi. The relationship between complex formation and antimicrobial activity is discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

18.
Alternative materials have long been studied and developed to replace conventional skin dressings with the emergence of new biopolymers and development of polymeric film fabrication techniques. As a new material for polymeric dressings, films of poly(hydroxybutyrate) (PHB) blended with esterified alginate (ALG‐e) and poly(ethyleneglycol) was studied. The esterification of sodium alginate (ALG‐e) generated a material with some amphiphilic characteristics and increased compatibility with the PHB. PEG was added as plasticizer in PHB/ALG‐e films was also tested, since PEG is often used in blends with PHB to improve flexibility and reduce hydrophobicity. At the amounts studied, it was found that both PEG and ALG‐e increase the degree of crystallinity, but a decrease was observed in the hydrophobic nature of PHB films. At the maximum concentration of ALG‐e and PEG used an increase in water vapor permeability and a decrease in tensile strength was reached due to the synergistic effect caused by better homogenization of PEG and ALG‐e in the PHB matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44362.  相似文献   

19.
A new poly(ester amide) derived from L -alanine has been synthesized and characterized. The polymer has good fiber- and film-forming properties, as well as other characteristics like thermal stability and solubility in chloroform, which enhance its processing facilities. Degradation studies show that both pH and temperature influence in the hydrolisis rate that takes mainly place through the ester linkages. Degradation was also studied by using different enzymes. Results indicated that papain was the most efficient of these, and that the hydrolysis to water-soluble products could be attained in a few days. Basal cytotoxicity was assayed using a mouse L929 fibroblast permanent cell line. The MTT viability test was performed with liquid extract of the material (50 days, 37°C). An attachment and proliferation screening study with intact material was also carried out. No cytotoxic responses were detected, in either assay, after a 24- and 48-h incubation period with the cells. After 72 h a slight cytotoxicity was detected in the polymer material, while a more significant one was detected in the material extract. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1537–1549, 1998  相似文献   

20.
A new family of biodegradable amino‐acid‐based poly(ester amide)s (AA–PEAs) and amino‐acid‐based poly(ether ester amide)s (AA–PEEAs) consisting of reactive pendant functional groups (? COOH or ? NH2) were synthesized from unsaturated AA–PEAs and AA–PEEAs via a thiol–ene reaction in the presence of a radical initiator (2,2′‐azobisisobutyronitrile). The synthetic method was a one‐step reaction with near 100% yields under mild reaction conditions. The resulting functional AA–PEA and AA–PEEA polymers were characterized by Fourier transform infrared spectroscopy, NMR, and differential scanning calorimetry. These new functional AA–PEA and AA–PEEA derivatives had lower glass‐transition temperatures than the original unsaturated AA–PEA and AA–PEEA polymers, and their solubility in some organic solvents also improved. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

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