N-邻苯二甲酰化壳聚糖的合成与性能

通过邻苯二甲酸酐与壳聚糖在室温、均相条件下快速反应,制备一系列取代度不同的Ｎ–邻苯二甲酰化壳聚糖。经FTIR、1H–NMR检测证明酰化反应的发生。研究了投料物质的量比对产物的溶解性、特性黏度和相对分子质量的影响。并对产物吸湿保湿性能进行初步研究。     

一种制备丁二酰化壳聚糖的新方法

合成了甘氨酸盐酸盐离子液体([Gly]Cl),由1H-NMR对其结构进行了确证,并以其质量分数2%的水溶液为反应介质,制备水溶性丁二酰化壳聚糖。用XRD和FT-IR对产物进行了表征,结果表明:壳聚糖(CS)中引入了丁二酰基,并削弱了壳聚糖分子内和分子间的氢键作用,大大改善其水溶性。考察了反应时间、温度和反应物配比对丁二酰化壳聚糖取代度(DS)的影响,得到较佳的反应条件:反应时间4h,n(丁二酸酐):n(壳聚糖)=2.75,反应温度40℃,在该条件下丁二酰化壳聚糖的取代度达到90%以上。离子液体具有重复使用性,反应后的离子液体未经处理重复使用3次后,丁二酰化壳聚糖的取代度仍大于90%。     

苯基生色团修饰壳聚糖甲酸溶液中手性研究

在甲基磺酸体系中,分别将苯甲酰氯、对氯苯甲酰氯与壳聚糖反应,制备了具有发色团的苯甲酰化壳聚糖和对氯苯甲酰化壳聚糖。紫外光谱表征表明产物具有目标产物的结构特征。苯甲酰化壳聚糖、对氯苯甲酰化壳聚糖分别在254 nm和258 nm处具有苯基特征吸收峰。温度25℃,在质量浓度为250 mg/L时,苯甲酰化壳聚糖和对氯苯甲酰化壳聚糖甲酸溶液的圆二色谱信号均出现以苯基相应紫外吸收最大波长为中心的耦合裂峰（一个正峰和一个负峰）,表明发色团在壳聚糖螺旋链有序规则排列,壳聚糖分子链为左旋构象。对氯苯甲酰基发色团更适合测量甲酸溶液中壳聚糖构象特性。苯甲酰化壳聚糖和对氯苯甲酰化壳聚糖分子链构象受温度影响。     

O,O-双十二酰化壳聚糖自组装纳米药用泡囊

通过扫描电镜和原子力显微镜实验表明O,O–双十二酰化壳聚糖可形成一种新型的自组装纳米药用泡囊,其粒径主要分布在100～200nm。考察了3种不同酰化取代度的O,O–双十二酰化壳聚糖自组装泡囊的体外药物(维生素B12)释放行为。结果表明自组装泡囊的药物释放速率随酰化取代度的增大而降低。同时在自组装泡囊的制备过程中加入胆固醇,能引起自组装泡囊的药物释放速率增大。壳聚糖基材料的酰化取代度对自组装药用泡囊的载药量的影响较小,但对自组装药用泡囊的药物包封率有显著的影响。酰化取代度为1.3、1.4和1.7的三种O,O–双十二酰化壳聚糖自组装泡囊药物包封率分别为29.52%、31.55%和39.88%。     

松香-壳聚糖基梳型离子型高分子表面活性剂的制备及性能研究(摘要)

<正>以脱氢枞胺为原料首次合成了3-氯-2-羟丙基脱氢枞基氯化铵(CHPDMDHA)和烯丙基二甲基脱氢枞基氯化铵(ADMDHA),并创新提出以CHPDMDHA和ADMDHA作为活性季铵盐对壳低聚糖(LWCTSs)、N-羧甲基壳聚糖(N-CMC)、N,O-羧甲基壳聚糖(N,O-CMC)、N-羧乙基壳聚糖(N-CEC)和N,O-羧乙基壳聚糖(N,O-CEC)进行改性,分别得到了CHPDMDHA接枝壳低聚糖(CHPDMDHA-g-LWCTSs)、CHPDMDHA接枝羧烷基壳聚糖(CHPDMDHA-g-CACTSs)、ADMDHA接枝壳低聚糖(ADMDHA-g-LWCTSs)和ADMDHA接枝羧烷基壳聚糖(ADMDHA-g-CACTSs)等4个系列松香改性壳聚糖类梳型高分子表面活性剂。采用FT-IR、NMR、元素分析等手段表征了产物结构,并研究了所合成化合物的     

基于苯胺五聚体和壳聚糖的可降解聚合物的合成

用邻苯二甲酸酐对壳聚糖进行修饰,得到能溶于DMF、NMP等有机溶剂的邻苯二甲酰化壳聚糖,然后用邻苯二甲酰化壳聚糖和羧基封端的苯胺五聚体缩聚制得共聚物。通过模拟体液环境的体外降解实验,研究该共聚物的热稳定性及其降解性能。     

含二茂铁基的酰肼化合物的合成

以二茂铁二甲酰氯和芳甲酰肼为原料,采用微波法合成了9个N2,N2'-二芳甲酰基-1,1'-二茂铁二甲酰肼类化合物Ⅲ,并通过IR、1HNMR和ESI/MS对其结构进行了表征。紫外光谱研究表明,含吸电子取代基的化合物Ⅲf对阴离子F-、CH3COO-有识别作用,化合物Ⅲh、Ⅲi对F-、CH3COO-、H2PO4-有识别作用。初步的生物活性测试表明,取代基位于邻位的化合物Ⅲa、Ⅲb和Ⅲc对金黄色葡萄球菌、大肠杆菌有良好的抑菌作用。     

O-乙基-O-(2-甲酰基苯基)-N-(1-甲基乙基)硫代磷酰胺酯的制备及其氨解反应

在研究了水杨醛与O 乙基硫代磷酰二氯反应的基础上 ,首次报道了O 乙基 O (2 甲酰基苯基 ) N (1 甲基乙基 )硫代磷酰胺酯的合成 ,同时发现该标题化合物的氨解反应 ,给出了尚未见文献报道的O (2 甲酰基苯基 ) N ,N′ 二烷基硫代磷酰胺酯类化合物     

丙烯酰化壳聚糖的制备

设计了一种壳聚糖的改性方法。以壳聚糖(CS)和丙烯酸(AA)为原料,1-乙基-3-(3-二甲氨基丙基)碳二亚胺盐酸盐(EDC)为交联结合剂,用丙烯酰化的方式改性壳聚糖,幵成功地通过红外光谱法和核磁共振氢谱法测定粒子微观组成,验证了丙烯酰化壳聚糖的合成。得到带有碳碳双键的丙烯酰化交联壳聚糖,可以用于迚一步制成微凝胶,微球可以同药物一起被加工成丸剂、乳剂、微球、微囊、薄膜等制成控制释放体系,达到控制药物释放、延长药物疗效的作用。     

AlCl3催化邻甲氧基苯胺与丙烯腈加成反应的研究

报道了AlCl3催化邻甲氧基苯胺与丙烯腈发生Michael加成反应合成N-氰乙基-邻甲氧基苯胺、N,N-二氰乙基-邻甲氧基苯胺.结果表明,在60～64 ℃、10%(占邻甲氧基苯胺的摩尔百分数,以下同)无水AlCl3催化下反应12 h,生成N-氰乙基-邻甲氧基苯胺,收率88%;在80～84 ℃、60%无水AlCl3催化下反应16 h,生成N,N-二氰乙基-邻甲氧基苯胺,收率90%.用毛细管气相色谱法对合成的N-氰乙基-邻甲氧基苯胺、N,N-二氰乙基-邻甲氧基苯胺进行了含量的测定,并对其物性和结构进行了表征.     

Studies on the effect of substitution degree on the liquid crystalline behavior of cyanoethyl chitosan

An alkali–chitosan method was employed to prepare cyanoethyl chitosan (CNCS) with different degrees of substitution (DS) from chitosan by controlling the reaction time. The effect of the DS (from 0.36 to 1.21) on the liquid crystalline behaviors of CNCS was investigated. The critical concentration and texture of CNCS liquid crystalline in dichloroacetic acid and formic acid showed no obvious dependence on the DS. However, increase of the DS could enhance the birefringence of liquid crystalline solutions under a polarized microscope, which implied improved liquid crystallinity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2057–2061, 2000     

Synthesis and antimicrobial activity of Schiff base of chitosan and acylated chitosan

Chitosan, a biocompatible, biodegradable, nontoxic polymer, is prepared from chitin, which is the second most naturally occurring biopolymer after cellulose. Schiff base of chitosan, sorbyl chitosan, and p‐aminobenzoyl chitosan were synthesized working under high‐intensity ultrasound and their antimicrobial properties were analyzed against Escherichia coli, Staphylococcus aureus, and Aspergillus niger. The structures of the derivatives were characterized by FTIR spectroscopy and elemental analysis. The results of antimicrobial activities indicated that the antimicrobial activities of the derivatives increased with increasing the concentration. The antibacterial activity of schiff base of chitosan against E. coli was stronger, while acylated chitosan had better inhiting effect on S. aureus than others. It was also found that the antifungal activities of the derivatives were stronger than that of chitosan, and schiff base of chitosan was obviously superior to acylated chitosan. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

0’0-月桂酰壳聚糖的制备及表征

利用壳聚糖在甲磺酸溶剂中与月桂酰氯进行酰化反应,得到羟基上取代的0＇0-月桂酰基壳聚糖本实验制备了壳聚糖。通过元素分析计算产品的取代度,并对其进行了IR、1H-NMR表征。结果表明,通过此法月桂酰基能成功地接到了壳聚糖的羟基上,并获得较高的取代度。     

Antibacterial effects of chitosan and its water‐soluble derivatives on E. coli,plasmids DNA,and mRNA

The antibacterial activities of chitosan and its water‐soluble derivatives on E. coli were studied according to four influencing factors in vitro. The antibacterial study showed that chitosan, O‐hydroxyethyl chitosan (O‐HECS), and O‐carboxymethyl chitosan (O‐CMCS) could inhibit the growth of the microbial. To study the antibacterial mechanism, plasmid DNA pBR322 and pUC18 were selected to be the probes to find out the binding abilities of chitosans. Results showed that raw chitosan had a high binding ability with the plasmids and the influencing degrees were stable. The effects of chitosan derivatives on plasmids might be affected by space effect and static effect. With appropriate concentrations and molecular weights, the derivatives might have strong abilities to combine with DNA. The degree of influence of chitosan and its derivatives on plasmids had nothing to do with time. The experiment focusing on the relationship between chitosans and mRNA showed that O‐CMCS would hinder the synthesis of mRNA, and this may give some proof to its antibacterial mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3521–3528, 2007     

Miscible chitosan/tertiary amide polymer blends

The miscibility of five chitosan/tertiary amide polymer blend systems was studied. Based on the optical transparency of the blend and the existence of a single glass transition temperature, chitosan was found to be miscible with poly(N‐vinyl‐2‐pyrrolidone), poly(N‐methyl‐N‐vinylacetamide), poly(N,N‐dimethylacrylamide), poly(2‐methyl‐2‐oxazoline), and poly(2‐ethyl‐2‐oxazoline). Fourier transform infrared spectroscopy showed the existence of hydrogen‐bonding interactions between chitosan and the tertiary amide polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1785–1790, 2000     

Aggregation of hydrophobically modified chitosan in solution and at the air–water interface

Oleoyl‐chitosans (O‐chitosans), with three degrees of substitution (DS), were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of these polymers were characterized by ¹H NMR and FTIR. The results suggested the formation of an amide linkage between amino groups of chitosan and carboxyl groups of oleic acid. These O‐chitosans exhibited poor solubility in aqueous acidic solution. The solubility of O‐chitosans decreased as the DS values increased. The transmittance of O‐chitosans (2 g/L) with DS 5%, 11%, 27% in 1% (v/v) HCl solution were 69.5%, 62.7%, 48.6%, respectively. These O‐chitosans were not soluble at neutral or alkali pH. Formation of self‐aggregation was observed using pyrene as a fluorescent probe in the O‐chitosans aqueous solution. The increase of DS of O‐chitosans resulted in significant decrease of critical aggregation concentration (CAC). The CAC of the O‐chitosans with DS 5%, 11%, 27% were 79.43, 31.6, 10 mg/L, respectively. The surface tension of solution could be reduced slightly by all of the O‐chitosans. The surface tension of O‐chitosans solution decreased with the increase of DS values. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1968–1973, 2006     

Factors Influencing the Antibacterial Activity of Chitosan and Chitosan Modified by Functionalization

The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this analysis, we intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. The presence of several types of functional groups in the structure of the polymer and the fact that it has cationic properties are determinant for the increased reactive properties of chitosan. We analyzed the intrinsic properties of chitosan in relation to its source: the molecular mass, the degree of deacetylation, and polymerization. We also studied the most important extrinsic factors responsible for different properties of chitosan, such as the type of bacteria on which chitosan is active. In addition, some chitosan derivatives obtained by functionalization and some complexes formed by chitosan with various metallic ions were studied. The present research can be extended in order to analyze many other factors than those mentioned. Further in this paper were discussed the most important factors that influence the antibacterial effect of chitosan and its derivatives. The aim was to demonstrate that the bactericidal effect of chitosan depends on a number of very complex factors, their knowledge being essential to explain the role of each of them for the bactericidal activity of this biopolymer.     

Thermorheological complex behaviour of maltosyl-chitosan derivatives in aqueous solution

N-maltosyl-chitosans with different substitution degrees were prepared by reductive N-alkylation. Dynamic shear experiments were used to study the influence of degree of substitution (DS), polymer concentration and temperature on the viscoelastic properties of these semi-synthetic polysaccharides. The attachment of the disaccharide as side chains drastically changed solubility and rheological behaviour of the ‘native’ biopolymer. At lower DS extensive interchain associations may develop, yet allowing for water solubility, but originating temporary gel-like networks. At higher DS, the bulky of the disaccharide groups leads to less extensive hydrogen bonding or hydrophobic interactions and the viscoelastic profile resembles more to an entangled high-molecular weight polymer. The combined effect of different types of interactions among the polysaccharide chains, including topological entanglements, but also more specific hydrogen bonding and hydrophobic interactions, is responsible for several peculiar rheological characteristics, such as strain-induced structuring, complex relaxation processes, elastic plateaus at low frequencies, anomalous scaling behaviour on concentration regarding the relaxation times and modulus, and complex temperature effects, including departures to the time–temperature superposition principle, which are strongly dependent on the polymer concentration, DS and temperature. Therefore, the explored approach demonstrated that branched chitosan derivatives could be produced with varied and tailorable rheological properties in aqueous media with expected enhanced applications.     

Synthesis,Characterization and Optimization of Water-Soluble Chitosan Derivatives

Chitosan was chemically modified using monochloroacetic acid at various reaction conditions. Chemical structure was confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The carboxymethyl chitosan (CM-chitosan) was prepared at different temperatures, water/isopropanol (IPA) ratios and alkali concentrations. Reaction conditions have great influence on the degree of substitution (DS) and, in turn, the solubility. The water solubility of chitosan derivatives depended upon modification conditions and degree of substitution.