聚乙二醇单甲醚接枝改性壳聚糖的研究

采用十二烷基硫酸钠(SDS)对壳聚糖(CS)链上的氨基进行保护,得到中间产物壳聚糖-十二烷基硫酸钠复合物(CS-SDS)。以六亚甲基二异氰酸酯(HDI)为偶联剂活化聚乙二醇单甲醚(mPEG)得mPEG-NCO。将mPEG-NCO接枝到CS-SDS上,脱除壳聚糖氨基保护,制得CS与mPEG的接枝共聚物CS-g-mPEG,并采用FTIR、1 HNMR、GPC、XRD、TG-DTG等方法对产物结构进行表征。XRD分析表明,CS-g-mPEG结晶度降低,溶解性提高;热重分析表明,CSg-mPEG降解温度升高,热稳定性提高;CS-g-mPEG的摩尔接枝率达到28.55%。     

邻苯二酰化壳聚糖与聚乳酸接枝共聚物的研究

选用三种不同分子量的壳聚糖进行实验,对接枝共聚物的制备的工艺及条件进行较为详细的研究.采用"保护氨基-接枝反应-脱保护"的接枝路线,将聚左旋乳酸接枝在不同分子量的壳聚糖主链上,制得壳聚糖接枝聚乳酸共聚物.结果表明:(1)通过改变投料比、温度、时间等条件确定最佳的工艺条件制备邻苯二甲酰化壳聚糖(PHCS).在投料比(CS...     

疏水改性壳聚糖的合成与乳化性能研究

壳聚糖(CS)不同的分子量和脱乙酰度赋予了其多样性,但强亲水性限制了其在食品、化妆品等领域的应用。因此,若通过疏水改性降低壳聚糖的强亲水性可扩展其作为乳化剂的应用。本文通过美拉德反应以酪蛋白疏水多肽(CHP)对不同分子量和脱乙酰度的壳聚糖进行疏水改性。以60℃,相对湿度75%,反应时间3天以及CHP和CS质量比1:3为美拉德反应的较优条件。获得接枝度为3.10%～15.08%的系列接枝物,并通过红外和荧光光谱对接枝物进行结构分析。经酪蛋白疏水多肽改性得到的接枝物可以用于稳定乳状液的制备。对乳状液稳定性进行考察,以质量分数为1%的接枝物稳定50%橄榄油的O/W乳状液。壳聚糖稳定的乳状液在7天破乳,而接枝物可以为乳液液滴提供较大的静电排斥力,为乳状液提供了良好的长期储存稳定性,保持28天不破乳。     

抗菌剂聚六亚甲基盐酸胍改性壳聚糖的制备与表征

以丙烯酸(AA)为键合剂修饰壳聚糖(CS),制备出含羧基的AA接枝CS(CS-AA);然后利用缩合剂DIC(N,N′-二异丙基碳二亚胺)及活化剂HOBt(1-羟基苯并三氮唑)将CS-AA中引入的羧基与抗菌剂PHMG(聚六亚甲基盐酸胍)进行酰胺化反应,最终制得CS-AA-PHMG(PHMG改性CS)抗菌剂。研究结果表明:CS分子链中已成功接枝了AA,CS通过键合剂、缩合剂和活化剂成功接入了抗菌剂PHMG;PHMG在CSAA-PHMG中的接枝含量为(9.5±2.0)%,符合目标物抗菌性及抗菌持久性的指标要求。     

丁二酸酐酰化壳聚糖-g-PHB纳米微球的制备与表征

首先用十二烷基硫酸钠(SDS)将壳聚糖(CS)的氨基进行保护,得到油溶性产物SCS;以二丁基镁为引发剂引发β-丁内酯开环聚合合成聚β-羟基丁酸酯(PHB),以六亚甲基二异氰酸酯(HDI)为改性剂对PHB端基进行活化;然后将PHB接枝到SCS分子链上得到两亲性接枝聚合物SCS-g-PHB;再将壳聚糖氨基脱保护,得到CS-g-PHB;用丁二酸酐酰化得到具有一定pH值响应性的丁二酸酐酰化接枝聚合物SC-g-PHB;最后,通过层层自组装技术制备了具有核壳结构的SC-g-PHB纳米微球;并通过FTIR、1 HNMR、TGA、SEM、TEM和DLS对其结构进行了表征。结果表明,CSg-PHB的接枝率为21.5%,SC-g-PHB纳米微球具有明显的核壳结构,粒径在200nm左右,是一种新型的靶向药物载体。     

壳聚糖的光敏改性及其胶束化行为

用1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)在室温下催化壳聚糖(CTS)上的氨基与巯基乙酸的羧基反应生成酰胺键,得到侧基有巯基封端的CTS-HS,以PEG2 000为增溶剂在水溶液中与CTS-HS络合后冷冻干燥得到CTS-HS/PEG复合物。以偶氮二异丁腈(AIBN)为引发剂,甲基丙烯酰氧乙基肉桂酸酯(CEMA)和聚乙二醇甲基丙烯酸酯(MPEG)为共聚单体,加入含巯基的CTS-HS/PEG复合物为链转移剂进行自由基溶液聚合,得到壳聚糖光敏接枝物CTS-g-P(CEMA-co-MPEG)。用FTIR对壳聚糖光敏接枝物结构进行了表征。将壳聚糖光敏接枝物溶于水,在水溶液中直接形成胶束,用紫外-可见光分光光度计、Zeta电位仪、纳米粒度仪和透射电子显微镜研究了胶束的性质和形态。以白油为油相,研究了壳聚糖光敏接枝物的乳化性能。结果表明,壳聚糖光敏接枝物CTS-g-P(CEMA-co-MPEG)具有光敏性,可吸收波长在275 nm左右的紫外线,可在水溶液中自动形成粒径为120 nm左右的球形胶束,所得胶束在较宽的pH范围内均可稳定存在,并有较好的乳化性能。     

聚乙二醇单甲醚接枝壳聚糖的合成与表征

通过官能团偶联反应,将端基改性为醛基的聚乙二醇单甲醚(mPEG)按一定配比,在适宜条件下与壳聚糖(CS)反应,制得了梳状的可溶于水的聚乙二醇单甲醚接枝壳聚糖(mPEG g CS)。采用元素分析、红外光谱和透射电镜等方法对产物的结构和性质进行表征。研究表明,所制得的mPEG g CS在水溶液中能够自组装成胶束,并表现出有别于壳聚糖的流变性。     

双有机改性磁性膨润土对Cu(Ⅱ)和Zn(Ⅱ)的吸附

为了提高膨润土对Cu(Ⅱ)和Zn(Ⅱ)的吸附性能,采用羧甲基纤维素钠(SCMC)和壳聚糖(CS)通过席夫碱反应形成的复合物(SCMC/CS)对磁性膨润土(MB)进行改性,制备SCMC/CS修饰的磁性膨润土(SC/MB),研究改性膨润土吸附Cu(Ⅱ)和Zn(Ⅱ)的性能并分析吸附机理.结果表明,SC/MB对Cu(Ⅱ)和Zn...     

CS-HPMCP接枝共聚物的制备

以壳聚糖(CS)和羟丙甲纤维素邻苯二甲酸酯(HPMCP)为原料,通过1-乙基-(3-二甲基氨基丙基)碳酰二亚胺盐酸盐(EDC)/N-羟基琥珀酰亚胺(NHS)偶联剂制备CS-HPMCP接枝共聚物,利用傅里叶变换-红外光谱仪,紫外可见分光光度计,接触角测量仪,差式扫描量热仪,X射线衍射仪对该接枝共聚物进行表征,判断接枝是否成功,测量接枝率并考察了接枝后亲水性、热稳定性、结晶性的变化。结果表明:通过接枝,改善了HPMCP与CS作为单体的性能,当CS分子量为50 000、HPMCP用量为1 g、EDC/NHS质量比为2∶1时,接枝共聚物中HPMCP的接枝率达到最大值73.42%。通过接枝改性使CS与HPMCP在各项性能上相互改善相互促进,从而获得性能更优异的生物医用材料。     

负载锌酞菁的二氧化硅纳米载体在光动力疗法的应用

在传统介孔二氧化硅合成的基础上,以壳聚糖的Ca2+溶液作为扩孔剂,利用层层自组装技术包裹CS(壳聚糖)/HA(透明质酸)层,制备得到了可降解的大孔二氧化硅[DMSNs@(CS/HA)],在DMSNs@(CS/HA)上负载疏水性药物锌酞菁(ZnPc),得到了负载锌酞菁的二氧化硅纳米载体[DMSNs@(CS/HA)@ZnPc]。将其应用于光动力学抗肿瘤研究。采用SEM、TEM、FTIR、XRD、UV-vis、N2吸附等温线和荧光成像技术对DMSNs@(CS/HA)和DMSNs@(CS/HA)@ZnPc进行了物相、形貌、孔径分布、结构、肿瘤光动力学治疗测试。结果表明,当DMSNs@(CS/HA)纳米载体的质量浓度为50 mg/L,Hela细胞的相对存活率高达93.2%,而负载ZnPc并在近红外光照10 min后,细胞存活率则锐减到36.2%。细胞存活率及其荧光成像实验均表明DMSNs@(CS/HA)纳米载体具有良好的生物相容性,可有效负载ZnPc,并应用于近红外照射下光动力学抗肿瘤。     

Chitosan/P3HT biohybrid films as polymer matrices for the in-situ synthesis of CdSe quantum dots. Experimental and theoretical studies

Biohybrid nanocomposite films were obtained through a simple two-step methodology. Films of chitosan/poly(3-hexylthiophene) (CS/P3HT) were used as polymer matrices for the in-situ synthesis and stabilization of CdSe quantum dots. The biohybrid materials were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, UV–visible spectroscopy, thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence spectroscopy (PL). The effects of the P3HT composition on the properties of the QDs in the films were analyzed. The results confirmed that CS/P3HT films provided an adequately confining matrix for the growth of CdSe QDs with a fairly uniform size and revealed that the interactions between the CdSe nanoparticles and the CS/P3HT matrix mainly involved the  OH and  NH₂ groups. The optical band gaps of the biohybrid nanocomposite films were estimated. The results of photoluminescence revealed that a charge transfer phenomenon occurred in the polymer system. Finally, theoretical analyses suggest that the CdSe QDs would be preferentially located onto the chitosan domains.     

Fabrication and in vitro investigation of nanohydroxyapatite,chitosan, poly(L‐lactic acid) ternary biocomposite

The nanohydroxyapatite/chitosan/poly(L ‐lactic acid) (HA/CS/PLLA) ternary biocomposites were prepared by blending the hydroxyapatite/chitosan (HA/CS) nanocomposites with poly(L ‐lactic acid) (PLLA) solution. Surface modification by grafting D ‐, L ‐lactic acid onto the HA/CS nanocomposites was designed to improve the bonding with PLLA. The FTIR and ¹³C‐NMR spectrum confirmed that the oligo(lactic acid) was successfully grafted onto the HA/CS nanocomposites, and the time‐dependent phase monitoring showed that the grafted copolymers were stable. The TEM morphology of the HA/CS/PLLA ternary nanocomposites showed that nano‐HA fibers were distributed homogeneously, compacted closely and wrapped tightly by the CS and PLLA matrix. The ternary biocomposites with the HA content of 60 and 67 wt % exhibited high compressive strength of about 160 MPa and suitable hydrophilicity. The in vitro tests exhibited that the ternary biocomposites have good biodegradability and bioactivity when immersed in SBF solutions. All the results suggested that the n‐HA/CS/PLLA ternary biocomposites are appropriate to application as bone substitute in bone tissue engineering. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and characterization of chitosan‐stearate complexes and in vitro evaluation on the adsorption of deoxycholic acid salt

Chitosan‐stearate complexes (CSC) were prepared by reacting chitosan (CS) with stearic acid. The formation and characteristics of CSC were studied by FTIR spectroscopy, X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the complexes were synthesized by the electrostatic interaction between the amino group of CS and the carboxyl group of stearic acid. The crystallinity and thermal stability of complexes decreased with the increasing content of stearic acid adsorbed by CS through electrostatic interaction. The in vitro assays show that the complexes of CS adsorbed more deoxycholic acid salt than CS per se at the same pH than that of chitosan. Moreover, CSCs which were more hydrophobic bound bile salt more effectively. POLYM. ENG. SCI., 54:592–597, 2014. © 2013 Society of Plastics Engineers     

Surface modification of polypropylene film by grafting with vinyl monomers for the attachment of chitosan

Polypropylene (PP) film activated by corona discharge treatment was grafted with methyl methacrylate (MMA) and acrylic acid (AA). The grafted PP was characterized by spectral, thermal analysis and swelling behavior which confirmed the occurrence of the grafting. The water vapor and oxygen permeability (OTR and WVTR) as well as the mechanical properties have been enhanced by grafting with both AA and MMA. The grafted PP was further immobilized with chitosan (CS) using ceric ammonium nitrate (CAN) as an initiator under ultraviolet radiation. The chitosan immobilized grafted film was characterized by FTIR, mechanical properties, thermal properties and swelling measurements. Scanning electron microscope (SEM) confirmed that the CS is bonded to the grafted PP film. The CS modified PP film has acquired enhanced antibacterial and antifungal properties.     

壳聚糖/聚丙烯酸水凝胶的制备及对Cu2 和Cd2 的吸附性能

以丙烯酸(AA)和壳聚糖(CS)为原料,N,N''-亚甲基双丙烯酰胺(MBA)为交联剂,利用辉光放电电解等离子(GDEP)技术在水溶液中一步引发制备壳聚糖/聚丙烯酸(CS/PAA)水凝胶。采用FT-IR、XRD和SEM对水凝胶的结构和形貌进行表征,考察了溶液pH、吸附时间和初始浓度对Cu2 和Cd2 吸附的影响,探讨了水凝胶的重复利用性。结果表明,丙烯酸成功接枝到壳聚糖链上,水凝胶呈现多孔的三维网络结构,CS/PAA对Cu2 和Cd2 的吸附符合Langmuir 吸附等温式和准二级动力学模型,由Langmuir 模型得到的最大理论吸附量为161.8和327.9 mg/g,该水凝胶在EDTA-4Na溶液中具有良好的再生和重复利用性。     

Antibacterial and biodegradable properties of polyhydroxyalkanoates grafted with chitosan and chitooligosaccharides via ozone treatment

Acrylic acid was grafted to ozone‐treated poly(3‐hydroxybutyric acid) (PHB) and poly(3‐hydroxybutyric acid‐co‐3‐hydroxyvaleric acid) (PHBV) membranes. The resulting membranes were further grafted with chitosan (CS) or chitooligosaccharide (COS) via esterification. These CS‐ or COS‐grafted membranes showed antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, methicilin‐resistant Staphylococcus aureus (MRSA), and S. aureus. The antibacterial activity to E. coli was the highest, whereas the antibacterial activity to MRSA was the lowest among these four bacteria tested. Acrylic acid grafting can increase the biodegradability with Alcaligens faecalis, whereas CS and COS grafting can reduce the biodegradability. In addition, CS‐grafted PHBV membrane showed higher antibacterial activity and lower biodegradability than COS‐grafted PHBV membrane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2797–2803, 2003     

改性碳纳米管/壳聚糖复合材料的制备及防污性能

通过控制溶液的pH,在酸性条件下制备了单层多巴胺改性的多壁碳纳米管,然后以戊二醛作为反应中间桥梁,共价接枝制备得到碳纳米管/壳聚糖复合材料。通过透射电子显微镜(TEM)、红外光谱(FTIR)和热重分析法(TGA)对复合材料的结构和性能进行表征,结果表明碳纳米管的管壁外面和管端都被均匀包覆起来,包覆层厚度在6 nm左右;采用多巴胺单层膜包覆碳纳米管,达到了减小对碳纳米管结构造成破坏同时增加表面活性基团数量的目的,使得复合材料中壳聚糖的接枝量增加到71.78%。复合材料兼具了壳聚糖和碳纳米管在抑菌性、缓释、硅藻生长抑制方面优异的性能,在对大肠杆菌、金黄色葡萄球菌、鳗弧菌及小舟形藻、成排舟形藻的防污性能实验中,复合材料在抑菌及抑制硅藻生长方面均表现出广谱、长效的抑制性能。     

Stearic acid grafted chitosan/epoxy blend surface coating for prolonged protection of mild steel in saline environment

Chitosan (CS) is a promising candidate for green anticorrosive coating owing to its film forming nature, complexation with metals, biocompatibility, and varied surface functionalization. This paper illustrates the surface properties of chitosan film which is modified by grafting with stearic acid via a water-soluble coupling agent, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). The interaction between chitosan and stearic acid were investigated theoretically by Gaussian 09 package. The purified co polymeric films so formed were characterized by FTIR-ATR, NMR, XRD, TGA, CHNSO, SEM, AFM and EDX techniques. Stearic acid grafted CS film was developed on mild steel surface via dip coating technique and investigated for its corrosion resistance in 3.5% NaCl via electrochemical techniques. EIS measurements and potentiodynamic polarization studies have proven that the grafted CS when blended with epoxy resin offers better corrosion protection to mild steel in saline environment. The coating offers prolonged protection for the metal surface with enhanced barrier properties and hydrophobic nature.     

Biocompatibility and antibacterial activity of chitosan and hyaluronic acid immobilized polyester fibers

Poly(ethylene terephthalate) (PET) fibers were treated with ⁶⁰Co‐γ‐ray and grafted with acrylic acid. The resulting fibers were further grafted with chitosan (CS) via esterification. Afterward, hyaluronic acid (HA) was immobilized onto CS‐grafting fibers. The antibacterial activity of CS against S. aureus, E. coli, and P. aeruginosa was preserved after HA‐immobilization. After immobilizing HA, the L929 fibroblasts cell proliferation was improved forCS‐grafting PET fiber. The results indicate that by grafting with CS and immobilizing with HA, PET fibers not only exhibit antibacterial activity, but also improve the cell proliferation for fibroblast. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 220–225, 2007     

壳聚糖在离子液体中的均相接枝共聚

以离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为反应介质,壳聚糖(CS)与L-丙交酯(L-LA)发生均相接枝共聚反应,得到了壳聚糖与L-丙交酯的接枝共聚物。考察了单体和催化剂的用量、反应的温度和时间对接枝率的影响规律。并利用红外光谱、核磁共振氢谱、热重分析等对接枝共聚物进行了表征,证实了L-丙交酯在壳聚糖分子链上发生了接枝共聚。实验结果表明,在[BMIM]Cl中进行的L-丙交酯与壳聚糖的均相接枝共聚反应效率高于非均相反应。