壳聚糖-g-N-羧甲基-2-硫代-4，5-2H咪唑啉酮的制备及其抑菌性能

以2-溴乙酸、壳聚糖、2-硫代四氢咪唑啉酮为原料,合成了不同接枝率的壳聚糖-g-N-羧甲基-2-硫代-4,5-2H咪唑啉酮（CTS-g-CSIDZ）,并对其理化性质进行了考察。用络合滴定法测定了该聚合物对Cd²⁺,CrO4^2-,Fe³⁺,Cu²⁺,Pb²⁺等重金属离子的吸附作用;进行了聚合物的悬菌定量实验,测定了接枝聚合物对一系列细菌的抑制能力;采用失重法研究了合成的聚合物在1mol/L HCl溶液中对N80钢片腐蚀的抑制作用。结果表明,部分接枝的CSIDZ比小分子化合物具有更高的对测试的多数金属离子吸附作用的热稳定性;接枝CSIDZ具有较强的抑菌效果,最小抑菌浓度为5.10 g/L;接枝CSIDZ比小分子缓蚀剂具有更高的热稳定性,在90 ℃时对N80钢片的缓蚀效率仍然可以达到71.1％,且用量仅为小分子化合物CSIDZ的1/2。     

Cu0-Fe3O4@壳聚糖微球的制备及其对染料污染物的催化氧化

采用Fe²⁺以及Cu²⁺与壳聚糖形成的双金属络合物作为前驱体溶液,一步成球后通过水热法制得Cu⁰-Fe₃O₄@壳聚糖微球。表征结果证明,Cu⁰以及Fe₃O₄均以纳米尺寸均匀镶嵌在壳聚糖微球中。当此壳聚糖微球投加量为0.5 g/L, H₂O₂投加量为40 mmol/L时,对初始浓度为20 mg/L的活性红73在60 min中内的脱色效率可达99%,且在pH 3.0～9.0范围内均能维持较高的效率。纳米Cu⁰在有氧条件下表面易形成Cu₂O层,不仅能够活化H₂O₂产生·OH,还可提供电子加快Fe(Ⅲ)/Fe(Ⅱ)之间的循环,使类芬顿反应高效进行。     

硫脲壳聚糖微量银配合物的制备及抑菌活性

由硫脲壳聚糖和微量的AgNO3反应得到硫脲壳聚糖Ag+配合物。 通过红外光谱对其结构进行了表征。 研究了壳聚糖、硫脲壳聚糖、硫脲壳聚糖-Ag+配合物及AgNO3对大肠杆菌和金黄葡萄球菌的抑菌活性,并测定了其最低抑菌浓度(MIC)和最低杀菌浓度(MBC)。 结果表明,硫脲壳聚糖-Ag+配合物的抑菌活性强于壳聚糖和硫脲壳聚糖,且其MIC和MBC均为100 mg/L（游离Ag+含量为0.032 mg/L）,低于AgNO3的MIC和MBC（均为120 mg/L）。     

改性壳聚糖抗菌纳米微球的制备

以卤胺化合物为抗菌基团对壳聚糖接枝改性, 并制备成纳米微球, 提高壳聚糖的抗菌性能. 通过核磁共振和紫外光谱对改性壳聚糖进行结构表征; 探讨了改性壳聚糖浓度、 三聚磷酸钠浓度及两者体积比对纳米微球的形成和粒径分布的影响; 测定了纳米微球的抗菌性能. 结果表明, 在改性壳聚糖浓度为4.0 mg/mL, 三聚磷酸钠浓度为2.0 mg/mL时, 形成的纳米微球形态稳定, 粒径分布均匀, 氯化后的纳米微球可在30 min内杀灭10⁷ cfu(cfu为单位体积中的菌落总数)的金黄色葡萄球菌和大肠杆菌, 表现出优异的抗菌性能.     

原子转移自由基聚合法改性壳聚糖及其抑菌性研究

合成了大分子引发剂(CS-Br)———壳聚糖(CS)接枝2-溴丙酰溴,然后以溴化亚铜与五甲基二乙烯三胺(PMDETA)为催化体系,氯甲基化甲基丙烯酸二甲氨乙酯季铵盐(DMC)为单体,利用原子转移自由基聚合法制备了新材料P(CS-Br-DMC)。重点研究了该材料对白色念珠菌、金黄色葡萄球菌和大肠杆菌的最低抑菌浓度(MIC)、抑菌圈直径及溶血性。同时考察了其在不同时间对三种菌种生长的影响,并且与壳聚糖本身的抑菌性进行了对比。结果表明,该材料比壳聚糖具有更好的水溶性和抑菌性,其对金黄色葡萄球菌的抑菌效果最佳。     

离子强度对膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂吸附Pb2+/Cu2+的影响

为揭示外加电解质离子强度对重金属离子吸附的影响规律与内在机制, 制备了膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂(BLPAMA), 研究了外加电解质离子强度对BLPAMA吸附单一和二元Pb²⁺/Cu²⁺的影响规律, 以及有、无外加0.2 mol/L NaNO₃时BLPAMA对二元Pb²⁺/Cu²⁺的吸附等温线、吸附热力学及吸附动力学。 结果表明, 在单一Pb²⁺或Cu²⁺溶液中, 随离子强度增加, Pb²⁺和Cu²⁺吸附量降低;在二元Pb²⁺/Cu²⁺溶液中, 随离子强度增加, Pb²⁺吸附量降低而Cu²⁺吸附量提高。     

儿茶素-稀土配合物的合成、表征及抗菌活性

以稀土(Re³⁺)和儿茶素(C)为原料,由液相合成法制备了3种(La³⁺-C、Gd³⁺-C、Er³⁺-C)配合物,结合傅里叶变换红外光谱、紫外光谱、X射线光电子能谱及配位数测定对配合物结构进行表征,确定了配合物的配位数为8。并采用牛津杯法、最小抑菌浓度(MIC)及最小杀菌浓度(MBC)等三种方法测定了Re³⁺-C对大肠杆菌、金黄色葡萄球菌、绿脓杆菌、沙门氏菌4种食源性细菌的抗菌性能。结果表明,这3种稀土配合物对各试验菌株均表现不同程度的抑制能力,相较Re³⁺和C而言,Re³⁺-C配合物的抑菌性能均有显著的提高。Re³⁺-C的抑菌活性顺序为：Gd³⁺-C > La³⁺-C > Er³⁺-C,其中Gd³⁺-C对4种细菌的MIC值分别为：1.550、0.097、0.780、1.550 μmol·mL⁻¹,MBC值分别为3.100、0.194、1.550、1.550 μmol·mL⁻¹,Gd³⁺-C对金黄色葡萄球菌表现出最佳的抑菌和杀菌能力。     

新型薄膜扩散梯度装置定量测量水环境中重金属形态

采用以纤维素透析膜为扩散相, 0.05 mol/L羧甲基纤维素钠(CMC)溶液为结合相的薄膜扩散梯度(DGT)装置(CMC-DGT)定量累积和测量水溶液中Cu²⁺, Cd²⁺和Pb²⁺的有效态; 考察了pH值和离子强度对CMC-DGT累积Cu²⁺, Cd²⁺和Pb²⁺的影响以及不同配体(乙二胺四乙酸二钠、 单宁酸和黄腐酸)对重金属有效态的影响; 测量了外加标的天然水和工业废水中重金属的有效态浓度; 并比较了不同结合相DGT装置对同一水体中重金属的有效态浓度. 实验结果表明, 0.05 mol/L CMC溶液对Cu²⁺, Cd²⁺和Pb²⁺累积容量分别为0.24, 0.11和0.45 mg/mL; 定量累积的最佳pH值范围分别为3.7～8.0, 4.7～9.0和4.7～8.0; 随着离子强度的增大, CMC-DGT对Cu²⁺, Cd²⁺和Pb²⁺的累积容量下降; CMC-DGT能够定量地累积配制水中的游离Cu²⁺, Cd²⁺和Pb²⁺, 回收率分别为92.1%, 100.6%和96.4%; 当有配体存在时, 随着配体浓度的增大, CMC-DGT测量的Cu²⁺, Cd²⁺和Pb²⁺有效态的浓度随之下降; 在过滤工业废水、 河水和湖水中, 不同结合相DGT装置对重金属有效态的测量值不同. 结果表明, CMC可作为DGT技术新的液态结合相.     

Study on the adsorption of heavy metals by a new magnetic hydrogel based on acrylic acid/ acrylamide/ sodium p-styrenesulfonateEI北大核心CSCD

通过水溶液法将Fe₃O₄@SiO₂负载到丙烯酸（AA）-丙烯酰胺（AM）-对苯乙烯磺酸钠（SSS）三元共聚水凝胶上,制备了具有高吸附能力的磁性水凝胶P（AA/AM/SSS）/Fe₃O₄@SiO₂。通过傅里叶变换红外光谱,X射线衍射光谱,拉曼光谱和比表面孔径分析表征了磁性水凝胶的微观结构。该磁性水凝胶平均孔径3.1 nm,属于介孔材料,且具有较好的热稳定性。吸附性能研究发现其对重金属离子Pb²⁺,Cu²⁺,Co²⁺,Cd²⁺和Ni²⁺均显示出较高的去除率,其中对Pb²⁺表现出优异的选择性,最大吸附量为497 mg/g。吸附动力学研究表明,吸附过程遵循拟二级动力学模型。再生实验发现该水凝胶经过7次吸附-解吸循环后,磁性水凝胶饱和吸附容量仍保持在265 mg/g。     

天然高分子壳聚糖作为吸附剂的吸附特性研究

甲壳素经化学改性制得的壳聚糖吸附Cu²⁺、Ni²⁺、Zn²⁺、Ca²⁺、Rb⁺、Cs⁺、Cd²⁺、Pb²⁺等离子的研究已有报道^[1],但吸附Pd²⁺等贵金属离子的研究尚不多见.本文报道了壳聚糖及其交联产物的造粒方法,并测定了该糖吸附Hg²⁺、Cu²⁺、Ag⁺、Pd²⁺等离子的特性.结果表明,化学交联后的颗粒(作吸附剂)在酸性条件下仍保持相当好的刚性,对Pd²⁺离子的吸附容量较大,在Pd²⁺、Cu²⁺共存时可选择性吸附Pd²⁺.     

羟丙基三甲基氯化铵壳聚糖的制备及其吸湿、保湿性能

抑菌活性;羟丙基三甲基氯化铵壳聚糖的制备及其吸湿、保湿性能     

Preparation of pH- and thermo-sensitive hydrogel by two-step grafting of acrylamide and acrylic acid onto preirradiated polyethylene film

Two-step grafting reaction of acrylamide (AAm) and acrylic acid (AAc) onto preirradiated polyethylene (PE) film were performed. The effects of irradiation dose, reaction temperature and reaction time on the grafting yield were studied. The effect of reaction time of the first step grafting on the yield of the second step grafting was also evaluated. The original and the irradiated PE films were tested by Fourier transform infrared (FTIR) spectroscopy in the attenuated total reflectance mode (ATR). The AAm and AAc grafted PE film appeared thermo- and pH-sensitive which are similar to the interpenetrating polymer network hydrogel. This revised version was published online in July 2006 with corrections to the Cover Date.     

Radiation synthesis of acrylic acid onto poly(tetraflouroethylene-perflourovinyl ether) film: Chemical modifications and electrical conductivity

Graft-polymerization of acrylic acid (AAc) monomer onto poly(tetraflouroethylene-perflouro vinyl ether) (PFA) copolymer film was carried out using gamma irradiation technique to synthesize grafted copolymer film PFA-g-PAAc (PFA-COOH). The effect of the dose on the degree of grafting of AAc onto PFA film was investigated. The results showed that the degree of grafting increases with increasing the irradiation dose. The grafted [PFA-COOH] film was chemically modified by reaction with aniline to produce modified [PFA-CO-NH-ph] film, followed by sulphonation reaction to introduce sulfonic acid (SO₃H) groups to get other modified [PFA-CO-NH-ph-SO₃H] film. The chemical structures of the grafted and modified films were identified by FT-IR, XRD, and SEM. It is of particular interest to measure the electrical conductivity of grafted and modified membranes as a function of degree of grafting. It was found that the conductivity of the grafted films increases with increasing the degree of grafting, however a slightly increase in conductivity was observed in [PFA-CO-NH-ph-SO₃H] sample. The electrical conductivity property of the modified PFA membranes suggests their possible use for fuel cell applications.     

γ-Ray-induced grafting of DMAEMA and AAc onto PP by two step method

Binary graft copolymerization of thermosensitive 2-(dimethylamino) ethyl methacrylate (DMAEMA) and pH sensitive acrylic acid (AAc) monomers onto polypropylene (PP) films was carried out by a two step method using a ⁶⁰Co gamma radiation source. The PP film was initially modified by grafting of DMAEMA through a direct method. The DMAEMA-g-PP film obtained was then subjected to radiation grafting of AAc by the pre-irradiation method to give (DMAEMA-g-PP)-g-AAc. The optimal conditions, such as reaction time, reaction temperature, monomer concentration, and dose were studied. The grafted samples were verified by the FTIR-ATR spectroscopy and swelling; thermal properties were analyzed by DSC and TGA.     

Preparation and Application of Quaternized Chitosan- and AgNPs-Base Synergistic Antibacterial Hydrogel for Burn Wound Healing

Infection is the major reason that people die from burns; however, traditional medical dressings such as gauze cannot restrain bacterial growth and enhance the healing process. Herein, an organic- and inorganic-base hydrogel with antibacterial activities was designed and prepared to treat burn wounds. Oxidized dextran (ODex) and adipic dihydrazide grafted hyaluronic acid (HA-ADH) were prepared, mixed with quaternized chitosan (HACC) and silver nanoparticles to fabricate Ag@ODex/HA-ADH/HACC hydrogel. The hydrogel, composed of nature biomaterials, has a good cytocompatibility and biodegradability. Moreover, the hydrogel has an excellent antibacterial ability and presents fast healing for burn wounds compared with commercial Ag dressings. The Ag@ODex/HA-ADH/HACC hydrogel will be a promising wound dressing to repair burn wounds and will significantly decrease the possibility of bacterial infection.     

Engineering quaternized chitosan in the 3D bacterial cellulose structure for antibacterial wound dressings

Balancing antibacterial properties with biocompatibility is of paramount importance for wound dressings loaded with antibacterial agents. In this work, a water soluble antibacterial agent, quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) with an appropriate degree of substitution was introduced into the bacterial cellulose (BC) network by adding it into the BC culture medium. Results indicated that the addition of HACC could affect the yield of BC, porous structure, thermal stability, water absorption and antibacterial properties. HBC-1 with a low content of HACC (13.65 ± 0.30%) cannot inhibit the biofilm formation of bacteria, while HBC-3 with a high content of HACC (62.05 ± 0.90%) has a low yield of BC and confused structure. HBC-2 with an optimum concentration of HACC (37.33 ± 0.80%) possessed a typical porous structure, acceptable thermal stability, good water absorption and favorable antibacterial properties against Staphylococcus aureus (S. aureus, ATCC 25923) and methicillin-resistant S. aureus (ATCC 43300). Most importantly, none of the HACC/BC films exhibited cytotoxicity to NIH3T3 cells. We believe that obtained HACC/BC films with favorable bactericidal properties and biocompatibility could be potential candidates for wound dressings in clinical applications.     

Synthesis,characterization, and biocompatibility of poly (acrylic acid/methyl methacrylate)-grafted-poly (ethylene-co-tetrafluoroethylene) film for prosthetic cardiac valves

The surface of poly (ethylene-co-tetrafluoroethylene) (PETFE) strip was grafted by acrylic acid (AAc) and methyl methacrylate (MMA) onto PETFE skeleton to improve the blood compatibility and reduce thrombogenicity for prosthesis. The grafting process was carried out via γ-rays technique as initiator for addition reaction. The optimal conditions were achieved by investigating the effect of different parameters during the grafting process such as exposure to irradiation dose, comonomer concentration, comonomer composition, and solvent. The surface microstructure and composition of copoly (AAc/MMA)-grafted-PETFE surface were characterized by Fourier transform infrared spectroscopy (FTIR), CHNS/O elemental analyzer, scanning electron microscopy (SEM), and electron spectroscopy for chemical analysis (ESCA). Further, heparin was introduced onto the grafted PETFE strip surface. The blood compatibility of modified strip was investigated by the determination of platelet adhesion and thrombus formation. The results indicate that the heparinized copoly (AAc/MMA)-grafted-PETFE sample is a good candidate for manufacturing the prosthetic cardiac valves.     

Temperature- and pH-responsive behavior of a novel copolymer of (PP-g-DMAEMA)-g-AAc

Graft copolymers of 2-(dimethylamino)ethylmethacrylate (DMAEMA) and acrylic acid (AAc) onto polypropylene films were investigated for obtaining a pH- and thermo-sensitive material. DMAEMA and AAc were grafted by direct irradiation and pre-irradiation methods, respectively, using a ⁶⁰Co γ-source. Due to the acidic and basic nature of the monomers, this novel copolymer corresponds to the class of polyzwitterions. Their behavior was studied in presence of different buffer solutions from pH 2 to 12 for different grafting percentages (from 9 to 362%) of AAc and keeping the DMAEMA grafting percentage constant. These modified films showed the same critical pH point at 7.6 in a range of temperatures from 23 to 37 °C. The swelling percentage showed a dependence on AAc content and pH. The lower critical solution temperature was observed at 36 °C when AAc content was less than 30% of grafting. The grafted films were characterized by swelling behavior, FTIR-ATR and UV–Vis spectrometry for study of loading and release of vancomycin as a model drug at room temperature.     

Microfiltration membranes prepared from polyethersulfone powder grafted with acrylic acid by simultaneous irradiation and their pH dependence

Polyethersulfone (PES) powder was grafted with acrylic acid (AAc) by simultaneous γ-ray irradiation. The kinetics of the radiation induced graft polymerization was studied and the grafted PES powder was characterized. Then, microfiltration (MF) membranes were prepared from PES-g-PAAc powder with different degrees of grafting (DG) under phase inversion method. The swelling behavior and the mean pore size of MF membranes were measured, and the filtration property was tested. The results showed that the pore size and the flux of MF membranes increased with the increase in DG. And, MF membranes’ properties were dependent on the pH value.     

Thermo- and pH-responsive polypropylene microporous membrane prepared by the photoinduced RAFT-mediated graft copolymerization

Thermo- and pH-responsive polypropylene microporous membrane prepared by photoinduced reversible addition–fragmentation chain transfer (RAFT) graft copolymerization of acrylic acid and N-isopropyl acrylamide by using dibenzyltrithiocarbonate as a RAFT agent. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM) were used to characterize the structural and morphological changes on the membrane surface. Results of ATR/FT-IR and XPS clearly indicated that poly(acrylic acid) (PAAc) and poly(N-isopropyl acrylamide) (PNIPAAm) were successfully grafted onto the membrane surface. The grafting chain length of PAAc on the membrane surface increased with the increase of UV irradiation time, and decreased with the increase of the concentration of chain transfer agent. The PAAc grafted membranes containing macro-chain transfer agents, or the living membrane surfaces were further functionalized via surface-initiated block copolymerization with N-isopropyl acrylamide in the presence of free radical initiator, 2,2′-azobisisobutyronitrile. It was found that PNIPAAm can be grafted onto the PAAc grafted membrane surface. The results demonstrated that polymerization of AAc and NIPAAm by the RAFT method could be accomplished under UV irradiation and the process possessing the living character. The PPMMs with PAAc and PNIPAAm grafting chains exhibited both pH- and temperature-dependent permeability to aqueous media.