银纳米线复合纳米级纤维的制备及性能研究

研究银纳米线的制备工艺以及银纳米线添加量对聚乙烯吡咯烷酮/银纳米线复合纳米级纤维性能的影响。采用水热反应法制备了银纳米线,通过静电纺丝方式制备了聚乙烯吡咯烷酮/银纳米线复合纳米级纤维。测试了不同反应条件下银纳米线及不同银纳米线含量的复合纳米级纤维的微观形貌、复合纳米级纤维的抗菌性能与光催化性能。结果表明:溶液静置30min后,在180℃时水热反应24h,获得的银纳米线形貌较理想;银纳米线质量分数达到5%时,复合纳米级纤维就具有显著的抗菌性;银纳米线质量分数为8%时,复合纳米级纤维具有较好的光催化性能。认为:聚乙烯吡咯烷酮/银纳米线复合纳米级纤维具有较理想的抗菌性和光催化性能。     

负压微波处理钛酸钡负载羊毛纤维

为实现微波对羊毛鳞片尖端的精准作用,根据微波辐射的选择性加热规律,选择介电损耗因数远高于羊毛纤维的纳米钛酸钡颗粒,利用超声波震荡将其负载在羊毛鳞片尖端翘角内,以吸收大部分微波辐射能。结果表明:40 kHz超声波在40℃预处理40 min时对羊毛纤维的损伤最小,由于超声波震荡作用,羊毛纤维表面缝隙内负载纳米钛酸钡颗粒,再经微波处理后的羊毛纤维鳞片尖端钝化,定向静摩擦效应降低了38.8%,定向动摩擦效应降低了61.8%,断裂强度与断裂伸长率与未处理羊毛基本相同,有效降低了微波对羊毛纤维力学性能的负面影响。此外,扫描电镜和红外光谱显示,40 kHz超声波在40℃清洗40 min,可将纳米钛酸钡颗粒完全清除,不影响纤维后续加工和应用。     

磁控溅射纳米纤维基银膜的结构和性能

室温条件下,采用直流磁控溅射方法,在醋酸纤维素(CA)纳米纤维表面沉积银纳米薄膜,采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对不同溅射功率的银纳米薄膜的形貌和微观结构进行表征;利用X射线衍射分析了银薄膜的结晶状态;研究了在不同溅射功率条件下制备的沉积纳米银薄膜复合纳米纤维的光学透射性能。结果表明:纳米结构银薄膜中银粒子直径较小且分散均匀,随着溅射功率的增加,银粒子尺寸增大的同时纳米薄膜的致密性和均匀性也相应的增加;制备的银薄膜均呈面心立方的多晶结构,并且其结晶性能随着溅射功率的增加而逐渐增强,同时抗紫外线透射能力也会明显增强。     

银纳米颗粒/二氧化钛/醋酸纤维素复合纤维的制备及其性能

以纳米TiO_2和Ag NO_3为添加剂,通过静电纺丝装置,成功制备了一种高性能抗菌复合纳米纤维。采用扫描电子显微镜、X射线能谱分析和琼脂平皿扩散法等手段对样品的形貌、纳米粒子的分布、化学态、抗菌性能等进行表征与分析。结果表明:Ag NO_3和TiO_2的质量分数都会对纤维的形貌产生影响,需选择合适的添加范围;在纤维中,醋酸纤维素中的氧原子与Ag之间存在着相互作用;银纳米颗粒的存在,使纤维在可见光区出现明显的吸收峰;银纳米颗粒和TiO_2良好的协同作用使纤维对大肠杆菌和金黄色葡萄球菌具有很好的抗菌效果。     

罗汉果皂苷的微波提取

中药罗汉果是广西特产，本文采用微波辅助提取技术，从罗汉果中提取罗汉果皂苷，并优化出最佳的微波提取功率、微波辐射时间、固液比及原料的粉碎度。结果表明，最佳的微波辐射时间是5rain、微波功率是495W、原料的粉碎度为不小于0．15mm及固液比为1：30，和传统的加热提取相比较，微波辅助提取的提取时间短，但具有较高的提取率。微波辅助提取的提取时间为5min时，提取率达76．56％，而传统的加热提取时间为2h时，提取率为68．46％。     

PET/纳米矿物粒子纤维的结构与性能

 将纳米矿物粒子和聚酯切片共混纺丝，经碱减量处理后制备了PET/纳米矿物粒子纤维．对纤维表面和横截面的SEM观察显示，纳米矿物粒子在纤维中的颗粒比较小，由表及里都分散的比较均匀，纤维存在明显的微孔结构．X射线衍射分析表明，添加纳米矿物粒子后，聚酯纤维的晶形没有改变，其晶粒尺寸增加，而结晶度和取向度降低．性能分析表明，相比普通聚酯纤维，其断裂强度有所降低，但断裂伸长率和断裂功增加，特别是导湿性能改善最为显著，而质量比电阻明显降低．     

导电粒子对改善微波加热食品中局部过热现象的研究

微波加热不均匀性是制约微波加热应用的主要瓶颈,在物料内部或边角处由于电磁场的集聚而产生的局部过热现象会导致加热产品的过热变性问题。该试验以正方体土豆为物料,在微波腔中置入导电粒子,利用其表面对电磁场的反射改变物料周围的电场分布,降低物料的局部热点,从而改善物料内的温度分布。利用COMSOL-Multiphysics软件模拟导电粒子对微波腔内电磁场分布和物料内温度分布的影响。结果表明:合理置入导电粒子可以降低物料的局部热点现象,从而为改善微波加热的均匀性和提高微波加热产品品质提供一种新的方法。     

丝胶-壳聚糖对兔毛的改性处理

采用壳聚糖作为固着剂,在微波场中运用丝胶对兔毛纤维进行改性处理。考虑丝胶质量分数、壳聚糖质量分数、微波处理液pH值、微波参数和水洗温度5个因素,对实验方案进行优化设计,并讨论了各因素对兔毛纤维改性处理效果的影响。根据改性处理综合效果确定最优方案为:丝胶质量分数2%,壳聚糖质量分数1.2%,微波处理液pH值4.5,微波参数为:P30火力加热7 min,停2 min,再加热7 min,水洗温度为常温。     

聚氨酯抗菌纳米纤维及其空气过滤性能

利用静电纺丝技术,在纺丝液中添加纳米银粒子,制备具有抗菌功能的聚氨酯(PU)纳米纤维膜,并分析了纺丝液配比及纺丝工艺等对纳米纤维膜结构和性能的影响。结果表明:当PU质量分数为14%,氯化锂(LiCl)质量分数为0.3%,纳米银粒子质量分数为0.1%时,纳米纤维形貌较均匀,纤维平均直径最小,为171 nm,纤维膜具有较强的抗菌性。此外,还探讨了不同走布速度下纳米纤维膜的过滤性能,当走布速度为0.18 m/min时,纳米纤维膜过滤效率达到最大,过滤效率为86.32%,过滤阻力为25.93 Pa。     

新型纳米银抗菌棉织物的制备及其性能检测

利用纤维素大分子自身的还原性和分散性,原位还原硝酸银溶液,制备得到了纳米银抗菌棉织物。采用紫外一可见分光光度计（UV-vis）、原子吸收光谱（AAS）、分光仪等测试了反应时间对棉织物表面银负载量和织物色差的影响,并进一步评价了所得纳米银棉织物的抗菌活性以及其细胞毒性。结果表明,处理后织物在422nm处存在光吸收峰,说明织物表面沉积颗粒为纳米银粒子,且均匀分布在织物纤维表面;当反应时间由10min延长至50min时,织物表面银粒子负载量由0．6890mg／g增加至1．3561mg／g,而织物颜色由原来的白色逐渐变为浅黄色。抗菌活性测试表明,纳米银抗菌棉织物具有优良的抗菌效果及耐洗涤性能,经20次循环洗涤后,其对大肠杆菌和金黄葡萄球菌的抑菌率仍分别高达98．5％和94．3％。细胞毒性测试表明,此抗菌织物对小鼠MC3T3-E1细胞为低毒性材料,细胞相容性较好。     

藜麦皂苷与纳米银配合物的制备及其协同抗菌性的研究

以藜麦皂苷和硝酸银为原料,通过生物还原法制备藜麦皂苷与纳米银配合物,并研究配合物的抑菌活性。利用紫外可见分光光度计（UV-vis光谱仪）、透射电子显微镜（TEM）对藜麦皂苷与纳米银配合物进行表征分析;通过抑菌圈实验、最低抑菌浓度（MIC）实验、最小杀菌浓度（MBC）实验等研究藜麦皂苷与纳米银配合物的协同抗菌性。结果表明,藜麦皂苷与纳米银配合物为球形,粒子直径大部分集中在10 nm附近,单分散性好;在420 nm处出现特征吸收峰。藜麦皂苷与纳米银配合物对食源性微生物有较好的抑制作用和协同抑制作用,其中对表皮葡萄球菌、金黄色葡萄球菌的抑制效果最好,抑菌直径分别为（11.33±0.58）、（10.67±1.15） mm,对正常胃黏膜上皮细胞（GES）及胃癌细胞（SGC）毒性较低。藜麦皂苷作为生物还原剂使纳米银的溶解性与分散性增强,保留了纳米银本身的广谱抗菌特性,并相互协同使纳米银抗菌活性增强。     

Bactericidal paper impregnated with silver nanoparticles for point-of-use water treatment

There is an urgent need for cheap point-of-use methods to purify drinking water. We describe a method to deactivate pathogenic bacteria by percolation through a paper sheet containing silver nanoparticles. The silver nanoparticles are deposited by the in situ reduction of silver nitrate on the cellulose fibers of an absorbent blotting paper sheet. The aim is to achieve inactivation of bacteria during percolation through the sheet, rather than removal of bacteria from the effluent by filtration. The silver-nanoparticle containing (AgNP) papers were tested for performance in the laboratory with respect to bacteria inactivation and silver leaching as suspensions of bacteria percolated through the paper. The AgNP sheets exhibited antibacterial properties toward suspensions of Escherichia coli and Enterococcus faecalis, with log reduction values in the effluent of over log 6 and log 3, respectively. The silver loss from the AgNP sheets was minimal, with values under 0.1 ppm (the current US EPA and WHO limit for silver in drinking water). These results show promise that percolation of bacterially contaminated water through paper embedded with silver nanoparticles could be an effective emergency water treatment.     

改性活性棉织物的纳米银原位组装抗菌整理

为实现纳米银在棉织物上的定向原位组装,以及纳米银抗菌纺织品的绿色、简便、高效、可循环的加工工艺,通过对棉织物进行氧化处理并接枝"核-壳"结构的改性聚酰胺超支化聚合物,制备了具有主动捕捉银离子、还原银离子、控制纳米银粒径、固着纳米银功能的活性棉织物。利用改性活性棉织物进行纳米银原位组装,对整理后的棉织物进行了表征,测试了其抗菌性能及耐洗性。结果表明:通过氧化、接枝处理能够将聚合物接枝到棉织物上,并且棉织物的活性改性处理对织物的力学性能影响不大。改性后的活性棉织物能够进行连续加工整理,整理过程实现零排放。整理后的棉织物纤维表面分布着大量5~25 nm的纳米银颗粒,其对金黄色葡萄球菌和大肠杆菌的抑菌率均在99.9%以上,且具有优异的耐洗牢度。     

Protein and silver nitrate interaction during finer wool production: enhancing tensile properties along with synthesis of nano silver

The simultaneous in situ synthesis of silver nanoparticles and slenderizing of wool fibers was carried out in one single step process without using external reducing agent. The functional groups of wool fibers were responsible for the reduction of silver ions into silver nanoparticles, and the possible interactions between the synthesized nanoparticles and the protein chains of wool fibers have been thoroughly discussed. According to the hypothesized mechanism, which was further proved by UV–vis absorption spectra, there is also a possibility of cross-linking formation within wool protein chains through diazotion reaction with amine groups of wool fibers. Duration of the process at the applied temperature allowed enough time for complete growth of the silver nucleus inside the protein chains, creating more cross-linking within the protein chains of wool fibers. Findings suggest the potential of the proposed method in producing fine wool fibers with enhanced tensile strength and slight color change.     

等离子体预处理对丙纶基材溅射银薄膜的影响

采用磁控溅射技术,在丙纶(PP)非织造布基材表面沉积厚度为0.5～2 nm的银薄膜,研究氩等离子体预处理对PP基材沉积银薄膜后表面形貌和抗菌性能的影响.原子力显微镜(AFM)分析表明,经氩等离子体处理后的纤维表面有明显的刻蚀痕迹,沉积的银粒子分布均匀、不易团聚;X射线能潜仪(EDX)分析表明.经氩等离子体预处理后,PP非织造布表面沉积的银粒子总量增加,表面沉积1nm厚的银薄膜,对大肠肝菌和金黄色葡萄球菌的抑菌率分别达到99.96%和100%.     

Development of cellulose-based bactericidal nanocomposites containing silver nanoparticles and their use as active food packaging

The use of nanomaterials, including metallic as active fillers in polymeric nanocomposites for food packaging has been extensively investigated. Silver nanoparticles (AgNPs), in particular, have been exploited for technological applications as bactericidal agents. In this paper, AgNPs were incorporated into a hydroxypropyl methylcellulose (HPMC) matrix for applications as food packaging materials. The average sizes of the silver nanoparticles were 41 nm and 100 nm, respectively. Mechanical analyses and water vapor barrier properties of the HPMC/AgNPs nanocomposites were analysed. The best results were observed for films containing smaller (41 nm) AgNPs. The antibacterial properties of HPMC/AgNPs thin films were evaluated based on the diameter of inhibition zone in a disk diffusion test against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The disk diffusion studies revealed a greater bactericidal effectiveness for nanocomposites films containing 41 nm Ag nanoparticles.     

Characterization of silver nanoparticles migration from package materials destined for contact with foods

There was studied migration of artificial silver nanoparticles from polyethylene films destined for package of such foods as bread and poultry into model media reproducing physico-chemical properties and composition of said products. Modification of films was performed by 5- or 10-fold spraying of silver nanoparticles on the surface of package material. Model media were composed from water, alcohol and plant oil according to US FDA and Russian Federal Service for Surveillance of Consumer Rights Protection and Human Well-Being official recommendation. Nanoparticles were detected in model media by means of transmission electron and atomic force microscopy. Quantification of silver in nanoparticles migrating from films was performed by mass-spectrometry with inductively coupled plasma. The results obtained showed that silver migrated from films into test media in form of nanoparticles with mean diameter close to 10-20 nm. Migrated particles were partially aggregated to complexes with dimension about 50 nm with degree of aggregation depending on media composition. Quantification showed that amounts of silver nanoparticles migrating in foods did not exceed save level of this nanomaterial consumption even in aggravated conditions when almost all volume of product was consumed in form packaged in films modified with nanosilver.     

Physical, chemical and microbiological changes in stored green asparagus spears as affected by coating of silver nanoparticles-PVP

Silver nanoparticles have recently gained increasing interests due to their antimicrobial activities in food processing applications. The aim of this study was to evaluate the effect of silver nanoparticles-PVP coating on weight loss, ascorbic acid, total chlorophyll, crude fiber, color, firmness and microbial qualities of asparagus spears stored at 2 and 10 °C. Asparagus samples were first sanitized with 100 mg l⁻¹ sodium hypochloride solution for 15 min. They were then immersed in coating solution containing silver nanoparticles for 3 min at room temperature. During 25-day storage at 2 or 10 °C, the coated asparagus demonstrated lower weight loss, greener color and tender texture compared with the control samples. The growth of microorganism was significantly hindered by the coating. Based on comprehensive comparison and evaluation, asparagus spears coated by silver nanoparticles could be kept in good quality for 25 days at 2 °C and for 20 days at 10 °C.     

纳米银海丝纤维抗菌性能和细胞毒作用的研究

 为确定纳米银海丝纤维的抗菌性能和细胞毒性作用，进行纳米银海丝纤维对金黄色葡萄菌和大肠埃希菌的定性、定量抗菌实验，采用MTT法进行了纳米银对正常人肝细胞（L-02）的细胞毒性实验以评价其使用安全性．结果显示：用0.2%以上的纳米银海丝纤维对金黄色葡萄球菌(AATCC25923)和大肠埃希菌(AATCC25922)作用4 h均产生了明显的抗菌作用，抑菌率大于75 %；纳米银颗粒对正常人肝细胞（L-02细胞）作用72 h，细胞相对增殖率（RGR）均在90.0 %以上，细胞毒性为1级，属无细胞毒性，细胞相容性好．纳米银海丝纤维具有高效抗菌活性，并且使用安全．