一种新星型大分子——六对甲酰胺乙酸甲酯苯氧基环三磷腈的合成及其热性能、水解性能的表征

本文以六氯环三磷腈（HCCP）为原料合成了一种以甘氨酸甲酯苯氧基为侧基的新星型环三磷腈化合物六对甲酰胺乙酸甲酯苯氧基环三磷腈（HGPCP）及其中间体,并采用^1H NMR,^13CNMR,^31PNMR,FFIR和元素分析技术对其结构进行了确认．通过TGA、DSC、FrIR技术和测定水解液的紫外光谱,水解残余物剩余质量,残余物的磷含量方法分别对化合物的热性能和水解性能进行了表征．通过比较HGPCP在酸碱环境下的水解结果,发现水解504h,样品的水解过程尚处于化合物侧链断裂阶段,其37℃在酸性缓冲溶液（pH1．0）下较中性缓冲溶液（pH1．0）更易水解．由于其可能在高温下生成交联结构,六对醛基苯氧基环三磷腈（HCPCP）,六对羧基苯氧基环三磷腈（HCPCP）和HGPCP在800℃时碳残余量分别为75％、47％和47％,都表现出良好的热稳定性．     

Biodegradable polyphosphazenes for drug delivery

Polyphosphazene derivatives having amino acid ester side groups were prepared by reaction of poly(dichlorophosphazene) with ethyl esters of amino acids. The in vitro degradation studies demonstrated that the rate of degradation depends on the nature of the amino acids. Introducing small amounts of hydrolytically sensitive groups such as depsipeptide ester or hydrolysis-catalysing moieties, such as histidine ethyl ester co-substituents, resulted in an increase of the degradation. The rate of hydrolytic degradation of the polyphosphazene material could be controlled by the content of the hydrolytically sensitive side groups or by blending hydrolysis-sensitive polymers with more stable derivatives. The results obtained from the in vivo implantation of biodegradable polyphosphazenes in mice indicate that the materials are very well tolerated by the animal body. Biodegradable polyphosphazenes have been used as matrix for the design of drug delivery systems. The rate of the in vitro release of mitomycin C from biodegradable polyphosphazenes can be controlled by changing the chemical composition of the polymer or by blending polymers of different chemical compositions.     

Fast atom bombardment in the structural identification of intermediates in the hydrolytic degradation of polyphosphazenes

Fast atom bombardment mass Spectrometry was employed in a study related to the hydrolytic degradation of alanine ethyl ester- and imidazole-substituted polyphosphazenes, to be used as matrices for drug release. Some intermediates were identified and their structural assignment was accomplished by means of mass-analysed ion kinetic energy data. All the detected species show the same phosphazene skeleton, consisting of a P₄N₃ chain, with an increasing number of alanine ethyl ester substituents, and no evidence was found for the presence of imidazole bound to the polymer backbone.     

Crosslinkable citronellol containing polyphosphazenes and their biomedical potential

An increased focus exists on the development of materials that might serve as ligament or tendon tissue engineering scaffolds. Requirements for a suitable candidate polymer include biodegradability, biocompatibility, and elasticity. In an attempt to meet these requirements novel citronellol‐containing polyphosphazenes were synthesized, characterized, and crosslinked to generate elastomers. Citronellol was chosen as a side group due to its anti‐inflammatory properties in addition to the presence of a double bond in its structure to permit polymer crosslinking. Alanine ethyl ester was chosen as a co‐substituent to tune hydrolysis rates without severely affecting the glass transition temperatures of the final polymers. Hydrolysis of the uncrosslinked polymers in the form of films in deionized water at 37 °C showed between ～8 and 16% mass loss and between a ～28 and 88% molecular weight decline over 12 weeks. Polymers were also crosslinked using ultraviolet radiation for increasing amounts of time. Preliminary mechanical testing of the homo‐citronellol polymer indicated increasing modulus and decreasing tensile strength with increased crosslink density. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2258–2265     

直链淀粉交联氨基酸酯取代聚膦腈杂化材料的制备

利用直链淀粉与甘/丙氨酸乙酯共取代聚膦腈交联, 制得了一种具有网络结构的新型杂化材料. 实验结果表明, 淀粉衍生物上的羟基转变为醇钠后, 可与聚膦腈分子链上的P-Cl键发生亲核取代反应; 所得聚合物膜无明显相分离, 力学性能优于具有相似组成的直链淀粉/聚膦腈共混膜, 表面亲水性和吸水率与对应的共混膜接近, 且均高于纯聚膦腈膜. 因此, 该聚合物可作为杂化生物材料用于药物控制释放和组织工程方面的研究.     

Random multiblock poly(ester amide)s containing poly(L‐lactide) and cycloaliphatic amide segments: Synthesis and biodegradation studies

Novel multiblock poly(ester amide)s containing poly(L ‐lactide) and cycloaliphatic amide segments were synthesized from telechelic oligomer of α,ω‐hydroxyl terminated poly(L ‐lactide), 1,3‐cyclohexylbis(methylamine), and sebacoylchloride by the “two‐step” interfacial polycondensation method. The blocky nature of PEAs was established by FTIR and ¹H NMR spectroscopies. The effect of relative content of ester and amide segments on the crystallization nature of PEAs was investigated by WAXD and DSC analyses. PEAs having lower content of PLLA, PEA 1 and PEA 2, showed a crystallization pattern analogous to polyamides, whereas PEA 3, having higher content of PLLA, showed two crystalline phases characterized by polyester and polyamide segments. Random nature of PEAs was observed from single T_g values. Biodegradation studies using the enzyme lipase from Candida Cylindracea showed higher degradation rate for PEA 3 than that for PEA 1 and PEA 2. FTIR, ¹H NMR, and DSC analyses of the degraded products indicated the involvement of ester linkages in the degradation process. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3250–3260, 2006     

Cellulose Derivatives Synthesized via Isocyanate and Activated Ester Pathways in Homogeneous Solutions of Lithium Chloride/N,N-Dimethylacetamide

Abstract

Cellulose carbamate and ester derivatives were synthesized in homogeneous solutions of lithium chloride (LiCl)/N,N-dimemyl-acetamide (DMAc) by the reaction of cellulose with ethyl 4-isocyanatobenzoate and the activated esters of N,N-dimethyl-aminobenzoic acids. Comparative reactions were performed with phenyl isocyanate and the activated ester of benzoic acid. All reactions were followed spectroscopically by FTIR, ¹H NMR, and ¹³C NMR. Degrees of substitution were calculated utilizing UV spectroscopy. The isocyanate reactions are facile allowing controllable degrees of substitution and high yields. By contrast, the activated ester pathway inherently results in lower degrees of substitution and lower yields due in part to undesirable side reactions.     

Synthesis and biomimetic mineralization of l‐proline substituted polyphosphazenes as bulk and nanofiber

This work presents the synthesis of polyphosphazenes bearing L ‐proline methyl ester (ProOMe) and 4‐hydroxy‐l ‐proline methyl ester (HypOMe), aiming for new bioactive polymers for bone repair. The polymers were characterized by ¹H and ³¹P NMR, FTIR, DSC, and TGA. Electrospun fibers were prepared using poly[bis(l ‐proline methyl ester)phosphazene] (PProP), and their potential for biomimetic mineralization, as well as the bulk material, were tested in simulated body fluid (1×SBF). Samples were analyzed between 24 h and 3 weeks of incubation using SEM/EDS and FTIR. After 24 h, spherical and flower‐like shapes of calcium phosphates (CaP) were crystallized on the bulk samples. The nanofibers presented spherical CaP crystals attached to them after 48 h of incubation. The Ca/P molar ratio of the crystals varied from 1.5 to 1.6. According to this study, PProP presents bioactivity in vitro, and its fibers offer sites for CaP nucleation like the collagen fibers in bone. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1318–1327     

Functionalized latexes as substrates for atom transfer radical polymerization

The application of atom transfer radical polymerization (ATRP) to the homopolymerization of 2‐hydroxyethyl acrylate and 2‐(methacryloyloxy) ethyl trimethylammonium chloride at the surface of a crosslinked polystyrene latex functionalized with alkyl bromide groups is reported. Polymerization was carried out using the surface groups of the dialyzed latex as initiators. The resulting hydrophobic core, hydrophilic shell latexes, were analyzed by FTIR, ¹³C‐NMR spectroscopy, and dynamic light scattering.     

Synthesis and hydrolytic degradation of stereoregular aromatic poly(ester amide)s derived from D‐xylose

Stereoregular poly(ester amide)s (PEAs) were prepared by the polycondensation method using naturally occurring D ‐xylose and aromatic diacids as the starting materials. The polymers were characterized by elemental analysis, GPC, IR, and ¹H‐ and ¹³C NMR spectroscopies. Thermal and X‐ray diffraction studies revealed them to be mainly amorphous. The polymers are hydrophilic and their degradation studies were carried out at 37 and 80 °C in buffered salt solution at pH 8. The degradation study was monitored by mass loss, GPC, IR, and NMR spectroscopies. The hydrolytic degradation of these PEAs occurred rapidly by hydrolysis of the ester functions to a final compound, which maintained the amide functions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Improvement of thermal resistance of polydimethylsiloxanes with polymethylmethoxysiloxane as crosslinker

Polymethylmethoxysiloxane (PMOS) with dense pendant Si-bound methoxy groups was synthesized by ring-opening polymerization and dehydrocoupling reaction. PMOS was incorporated with polydimethylsiloxane (PDMS) via hydrolytic condensation to prepare PMOS crosslinked polydimethylsiloxane. Highly crosslinked PMOS phases were in situ formed and the average crosslink density increased as the loading of PMOS went up. TG analysis results demonstrated that thermal decomposition process of PMOS crosslinked polydimethylsiloxane was divided into two stages, and the residual mass at 500 °C was 66 wt%. The pyrolysis reaction order was 0.974 and the activation energy for degradation was 78.0 kJ/mol. FTIR, XPS, XRD were performed to study the degradation residues. It was detected that dense PMOS phases could reduce the pyrolysis of polydimethylsiloxane at elevated temperature.     

Water‐soluble,biocompatible polyphosphazenes with controllable and pH‐promoted degradation behavior

The synthesis of a series of novel, water‐soluble poly(organophosphazenes) prepared via living cationic polymerization is presented. The degradation profiles of the polyphosphazenes prepared are analyzed by GPC, ³¹P NMR spectroscopy, and UV–Vis spectroscopy in aqueous media and show tunable degradation rates ranging from days to months, adjusted by subtle changes to the chemical structure of the polyphosphazene. Furthermore, it is observed that these polymers demonstrate a pH‐promoted hydrolytic degradation behavior, with a remarkably faster rate of degradation at lower pH values. These degradable, water soluble polymers with controlled molecular weights and structures could be of significant interest for use in aqueous biomedical applications, such as polymer therapeutics, in which biological clearance is a requirement and in this context cell viability tests are described which show the non‐toxic nature of the polymers as well as their degradation intermediates and products. © 2013 The Authors Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 287–294     

Investigation of swelling and network parameters of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels

The influence of poly(ethylene glycol) (PEG) plasticiser content and molecular weight on the physicochemical properties of films cast from aqueous blends of poly(methyl vinyl ether-co-maleic acid) was investigated using thermal analysis, swelling studies, scanning electron microscopy (SEM) and attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy revealed a shift of the CO peak from 1708 to 1731 cm⁻¹, indicating that an esterification reaction had occurred upon heating, thus producing crosslinked films. Higher molecular weight PEGs (10,000 and 1000 Da, respectively), having greater chain length, producing hydrogel networks with lower crosslink densities and higher average molecular weight between two consecutive crosslinks. Accordingly, such materials exhibited higher swelling rates. Hydrogels crosslinked with a low molecular weight PEG (PEG 200) showed rigid networks with high crosslink densities and, therefore, lower swelling rates. Polymer:plasticizer ratio alteration did not yield any discernable patterns, regardless of the method of analysis. The polymer-water interaction parameter (χ) increased with increases in the crosslink density. SEM studies showed that porosity of the crosslinked films increased with increasing PEG MW, confirming what had been observed with swelling studies and thermal analysis, that the crosslink density must be decreased as the M_w of the crosslinker is increased. Hydrogels containing PMVE/MA/PEG 10,000 could be used for rapid delivery of drug, due to their low crosslink density. Moderately crosslinked PMVE/MA/PEG 1000 hydrogels or highly crosslinked PMVE/MA/PEG 200 systems could then be used in controlling the drug delivery rates. We are currently evaluating these systems, both alone and in combination, for use in sustained release drug delivery devices.     

Synthesis and Properties of Biodegradable Copolymers of 9-Phenyl-2, 4, 8, 10-tetraoxaspiro-[5, 5]undcane-3-one and Ethylene Ethyl Phosphate

Novel biodegradable copolymer poly（CC-co-EEP） was synthesized by ring-opening copolymerization of cyclic carbonate 9-phenyl-2, 4, 8, 10-tetraoxaspiro-[5, 5]undcane-3-one （CC） and ethylene ethyl phosphate （EEP）. The obtained poly （CC-co-EEP）s were characterized by FTIR, ^1H NMR, ^13C NMR and gel permeation chromatography （GPC）. In vitro hydrolytic degradation of the copolymers were investigated in phosphate buffer solution （pH=7.4）. Hydrophilic phosphate units apparently improved the degradability of poly（carbonate-phosphate）.     

Synthesis and characterization of new biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups

<正>Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ~(31)p NMR,~1H NMR,~(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated.The results indicated that two polymers showed LCST phase transition over a range of concentrations from 0.13 to 15 wt%and pH-sensitive degradation properties.     

Dual crosslinked keratin-alginate fibers formed via ionic complexation of amide networks with improved toughness for assembling into braids

With the dwindling of petroleum resources worldwide, there is an immediate need for a renewable, environment friendly, cost effective and sustainable bio-resource in the textile industry. Here, we report a dual crosslinked fiber (DCF) derived from renewable biopolymers. In this study, keratin was extracted from bio-waste of chicken feathers with a thiol content of 0.172 mM. The extracted keratin was used to prepare dope with alginate at different ratios and N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride via amide linkages. The formation of covalently crosslinked dope was evidenced from FTIR and ninhydrin assay. The dope was then extruded in calcium bath to produce fibers with uniform diameter wherein the calcium ions were used to ionically crosslink the covalently crosslinked dope. The resulting dual crosslinked fibers were characterized in terms of chemical composition, surface morphology, mechanical properties, thermal degradation, and swelling. The strength, modulus and toughness of the dual crosslinked fibers were substantially improved by 27%, 20%, and 33% respectively than that of control alginate fiber. The gravimetric toughness of the optimised dual crosslinked fiber (724 J g⁻¹) was much higher than the values reported for Kevlar (78 J g⁻¹). We further assembled the dual crosslinked fibers into complex braided architectures using the textile techniques, demonstrating the flexibility of the fibers. We believe that this preliminary work of sustainable fiber production could open new insights into eco-friendly organic textile manufacturing and for tissue engineering applications.     

Synthesis,characterization, and thermal properties of biodegradable polyetheresteramide copolymers based on 11-aminoundecanoic acid

In this work, new aliphatic polyetheresteramide copolymers based on e-caprolactone, 11-aminoundecanoic acid, and poly(ethylene glycol) (PEG) were synthesized by the melt polycondensation method. The copolymers obtained were characterized by ¹H NMR, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetry, and wide-angle X-ray diffraction. Water absorption and hydrolytic degradation behavior was also studied. With the increase in PEG content, water absorption and the hydrolytic degradation rate increased accordingly.     

Degradable Polymers. IV. Degradation of Aliphatic Thermoplastic Block Copolyesters

Three block copolymers of poly(ethylene succinate) and poly(tetramethylene glycol) with about 20, 54, and 59 mol% polyether have been prepared and subjected to hydrolytic degradation at 37°C. The sample containing 59 mol% showed drastic changes in the properties after 3 months of degradation, whereas the other samples exhibited only minor changes. The tensile strength was completely lost, the molecular weight had decreased to 7% of the original value, and the crystallinity (measured as heat of fusion) had more than doubled. IR and ¹H-NMR analyses showed that the rates of release of the different polymeric blocks varied throughout the period of hydrolytic degradation. Fibers of the block copolymer poly(ethylene succinate)/poly(tetramethylene glycol) with poly(tetramethylene glycol) fractions ranging from 20 to 50 mol% have been analyzed by ¹³ C NMR to determine the molecular weights of the PES blocks and by reflection IR, ESCA, and SEM to investigate the surface composition. The molecular weights of the polyester blocks were inversely proportional to the mol% of polyether, and the values were in agreement with theoretical calculated values. The surface concentration of the polyether was found to be higher than that in the bulk and also independent of the mol% polyether in the range of study. A degradation mechanism is proposed which involves a combined effect of surface erosion and hydrolytic attack on the ester linkages connecting the amorphous polyether and the crystalline polyester blocks.     

Synthesis,thermal property and hydrolytic degradation of a novel star-shaped hexa[p-(carbonylglycinomethylester)phenoxy]cyclotriphosphazene

A novel star-shaped cyclotriphosphazene substituted by glycinomethylesterphenoxy and its intermediates are synthesized from hexachlorocyclotriphosphazene (HCCP). The structures are characterized by ¹H NMR, ¹³C NMR, 31P NMR, FTIR and elemental analysis. Their thermal properties are clarified by thermogravimetric analysis (TGA), differential scanning calorimentry (DSC) and FTIR, while hydrolytic degradation behaviour is studied with UV-vis spectrophotometer and by measuring the weight loss, and the phosphorus content of residue. According to hydrolysis behaviour of hexa[p-(carbonylglycinomethylester)phenoxy]cyclotriphosphazene (HGPCP) under different conditions, it is easy to hydrolyze in hydrochloric acid (pH 1.0) than in phosphate buffer (pH 7.4) at 37°C. And the sample hydrolytic degradation still remains at the stage of side groups’ break. The TGA data show that the thermal stability of the hexa[p-(aldehyde)phenoxy]cyclotriphosphazene (HAPCP), hexa[p-(carboxyl) phenoxy]cyclotriphosphazene (HCPCP) and HGPCP is so high that their char residues are 75%, 47% and 47% at 800°C, respectively, probably due to cross-linking between molecules.     

Synthesis,characterization and in vitro degradation of biodegradable polyesteramide based on lactic acid

A new type of biodegradable polyesteramide P(LA/AU) based on lactic acid and aminoundecanoic acid was synthesized by the melt polycondensation method. The copolymers obtained were characterized by FTIR, ¹H-NMR, DSC, and XRD. The in vitro degradation behavior of the copolymers was studied using weighing, ¹H-NMR, FTIR, DSC, and SEM. With the increase in aminoundecanoic acid units, the melting temperature and crystallinity increased, but the water absorption and degradation rate decreased accordingly. During degradation in vitro, the ester moiety decreased due to ester cleavage along the macromolecular main chain. As degradation proceeded, the melting temperature and crystallinity increased at first, then started to decrease because the crystalline phase was destroyed.