纤维素/壳聚糖可生物降解膜的制备及力学性能

将纤维素粉加入壳聚糖的乙酸溶液中制成生物降解膜。研究了影响共混薄膜力学性能的因素。结果表明，在共混体系中加入一定量的羧甲基壳聚糖作为增容剂有助于提高薄膜的强度；在乙酸质量分数为2％、壳聚糖质量分数为4％、纤维素与壳聚糖的质量比为1：1，羧甲基壳聚糖与壳聚糖质量比为1：15，共混搅拌20min的条件下，制得的共混膜拉伸强度达到88MPa。     

低聚壳聚糖种子包衣剂的制备及应用研究

以天然高分子低聚壳聚糖为杀菌成分,聚乙烯醇和甘油为添加剂,制得一种可降解种衣剂。研究了低聚壳聚糖、甘油的质量分数,低聚壳聚糖脱乙酰度等条件对所制种衣剂共混膜的抗拉强度、伸长率及膜透气率等参数的影响。结果表明,在一定范围内共混膜的抗拉强度和伸长率随低聚壳聚糖和甘油质量分数的增大而提高,膜透气率随低聚壳聚糖质量分数的增大而降低,但随甘油质量分数的增大而提高。种衣剂制备的最佳配比为:w(低聚壳聚糖)=2%,w(聚乙烯醇)=4%,w(甘油)=0.5%,反应温度45℃,反应时间1 h。该种衣剂具有良好的抑菌、杀菌、促进种子发芽作用,与空白对照组相比,提高玉米种子发芽率21%;使用该种衣剂处理棉花种子,与常规拌种相比,每100 m2产量可增加4.8 kg。     

丝素/羧甲基壳聚糖共混膜的结构与性能

利用丝素(SF)与羧甲基壳聚糖(CMCS)共混制取不同比例的SF/CMCS共混膜。研究了CMCS诱导的丝素构象转变行为,测试了共混膜的吸湿性、透湿性和保水性。当CMCS的质量分数为5%时,共混膜中丝素的构象以β-折叠为主;当CMCS的质量分数为10%时,共混膜中丝素的构象由β-折叠向α-螺旋发生转变;当CMCS的质量分数达到15%时,共混膜中丝素的构象向无规卷曲发生转变。当CMCS质量分数小于15%时,共混膜中SF与CMCS具有良好的相容性,溶胀度较小,吸湿性随CMCS含量的增加而迅速降低。     

聚乙烯醇／羧甲基壳聚糖共混膜的结构性能研究

为了提高羧甲基壳聚糖(CMCT)的物理机械性能,采用溶液共混法以羧甲基壳聚糖和聚乙烯醇(PVA)为原料制备不同比例的PVA/CMCT共混膜.用扫描电镜(SEM)观察了共混膜的截面形貌;用DSC、FTIR表征了共混膜的结构;测试了共混膜的力学性能.结果表明:PVA与CMCT分子链间在共混膜中有一定的相互作用,PVA的加入有利于改善CMCT的综合力学性能;当CMCT与PVA质量比为40:60时,两组分相容性好,膜表面均匀光滑规整,共混膜的断裂强度可以达到49 MPa.     

明胶/XNBR复合膜的制备及其性能的研究

采用水溶液共混法制备明胶XNBR复合膜。对该膜制备条件的研究表明:在明胶、XNBR质量分数比为10:1,反应温度70℃,反应时间90min的条件下所得膜的力学性能较好。对明胶/XNBR复合膜和明胶/壳聚糖复合膜进行了对比研究,结果表明,明胶/XNBR复合膜较明胶/壳聚糖复合膜有更好的力学性能。     

胶原蛋白/海藻酸/羧甲基纤维素共混膜的结构与性能

利用溶液共混法成功制备了新型生物膜材料—胶原蛋白/海藻酸/羧甲基纤维素共混膜(blend film),通过红外光谱、X-射线衍射、原子吸收光谱、扫描电镜对共混膜的结构进行了表征,同时测定了不同配比共混膜的透光率、拉伸强度(tensile strength)、断裂伸长率(breaking elonga-tion)、吸水率和水蒸汽透过率;对共混膜进行了热重和差示量热扫描分析。结果表明:共混膜中胶原蛋白、海藻酸钠和羧甲基纤维素之间具有较强的相互作用和良好的相容性,Ca2+交联、氢键以及静电引力等强烈相互作用使三元共混膜力学性能等得到了显著改善,其拉伸强度明显高于胶原蛋白膜、海藻酸膜和胶原蛋白/海藻酸二元共混膜、海藻酸钠/羧甲基纤维素二元共混膜,胶原蛋白质量分数为18.1%、海藻酸质量分数为45.5%和羧甲基纤维素为36.4%的三元共混膜中抗张强度最大,达102MPa。三元共混膜具有良好的力学性能,较好的热稳定性,作为一种新型生物材料可望在生物医学和食品材料领域得到应用。     

再生丝素/壳聚糖共混纳米纤维的结构与性能

以98%的甲酸为溶剂,不同质量分数的再生丝素溶液和3.5%的壳聚糖溶液以质量比70∶30共混静电纺丝。测定了壳聚糖的含量对共混膜的结构及力学、溶解等性能的影响。结果表明:随着壳聚糖相对含量的增加,丝素β化程度提高,纤维结晶度增大,丝素与壳聚糖以70∶30共混时的溶失率最小;甲醇处理后,溶失率明显降低;共混纳米纤维的断裂强度随着壳聚糖相对含量的增大而增加,柔软性也逐渐提高;共混纤维膜具有优异的抗菌性。     

羧甲基壳聚糖接枝聚丙烯酸高吸水树脂的制备及抑菌性能

以壳聚糖为原料,在碱性条件下与氯乙酸反应,合成了具有良好水溶性的羧甲基壳聚糖。以合成的水溶性羧甲基壳聚糖和丙烯酸为原料,通过接枝共聚反应合成了具有一定抑菌性能的羧甲基壳聚糖接枝聚丙烯酸高吸水树脂。探讨了羧甲基壳聚糖的合成条件,研究了羧甲基壳聚糖用量对树脂吸水性能和抑菌性能的影响。结果表明,当碱与壳聚糖的质量比为6∶1,氯乙酸与壳聚糖的质量比为5.5∶1时,羧甲基壳聚糖的产率和取代度均较高,在水中的水溶性较好;在相同的合成条件下,当羧甲基壳聚糖用量为丙烯酸质量的1.80%时,树脂具有较高的吸水性能及良好的抑菌性能,且均优于壳聚糖接枝聚丙烯酸高吸水树脂,其吸水倍率为980 g/g,对大肠杆菌和金黄色葡萄球菌均有抑制其生长的作用,抑菌率分别为91.7%和70.6%。     

羧甲基纤维素/海藻酸钠/壳聚糖复合膜的制备及其性能测定

根据海藻酸钠、羧甲基纤维素良好的成膜性和壳聚糖优异的抗菌性,将此三种基材复合制备一种具有抗菌功效的新型食品包装材料,用以减少塑料袋的使用,缓解环境压力。将海藻酸钠与壳聚糖、甘油混合后溶于醋酸,配制成海藻酸钠/壳聚糖混合溶液,将此混合溶液与羧甲基纤维素溶液按85∶15的质量比混匀,流延至玻璃板后60℃烘干,用CaCl_2溶液交联风干后制得羧甲基纤维素/海藻酸钠/壳聚糖复合膜。通过单因素实验结果选择三种基材的较优质量分数,再结合正交实验结果选择各质量配比的最佳组合。当海藻酸钠质量分数为1.5%、羧甲基纤维素质量分数为0.5%、壳聚糖质量分数为1.5%时,该复合膜的拉伸强度、水蒸气透过率、断裂伸长率等指标较优,壳聚糖的存在也能较好地抑制微生物的生长和繁殖。羧甲基纤维素/海藻酸钠/壳聚糖复合膜具有良好的抗菌性,将其应用于食品的包装具有广阔发展前景。     

丝素-聚己内酯纳米纤维膜的制备工艺

以六氟异丙醇(HFIP)为溶剂,采用静电纺丝技术制备丝素(SF)-聚己内酯(PCL)复合纳米纤维膜。采用热场发射扫描电镜、Image-Pro Plus图像分析和力学拉伸的方法表征了纳米纤维膜的结构与力学性能。通过设计的三因素四水平正交试验对复合纳米纤维膜的多个指标进行了分析,采取归一化数据处理及平均权重分配的方式量化了复合纳米纤维膜的品质,确定了共混复合纳米纤维膜制备的最优工艺参数,并且采用最佳工艺参数制备了SF-PCL复合纳米纤维膜,分析了其力学性能。结果表明:在溶质质量分数为6%、溶质SF与PCL质量比为3∶2、纺丝流速1.2 mL/h时,SF-PCL复合纳米纤维膜具有较好的品质;双轴拉伸时的破坏机制与单轴不同,其断裂应力和应变只是单轴时的一半左右,膜的力学性能表现为各向同性。     

Separation of alcohol–water mixture by pervaporation through a novel natural polymer blend membrane–chitosan/silk fibroin blend membrane

A novel natural polymer blend membrane, namely chitosan/silk fibroin blend membrane, was prepared. The selective solubility and the pervaporation properties of alcohol–water mixture were studied. The results showed that the membrane was water selective and the separation factor of ethanol–water mixture could be improved compared to pure chitosan membrane, when silk fibroin content in blend membrane was no more than 40 wt %. The blend membrane exhibited a best performance, (i.e., the water in permeate was large than 99 wt % when silk content was 20 wt % and the crosslinking agent–glutaraldehyde content was 0.5 mol %). The mechanism of improvement on pervaporation properties was explained by reducing the free volume and freeing hydrophilic groups of chitosan because of the strong intermolecular hydrogen bond forming between chitosan and silk fibroin in blend membrane. In addition, the influence of operation temperature and feed concentration as well as the pervaporation properties of isopropanol–water mixture were also studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 975–980, 1999     

Physical properties of silk fibroin/chitosan blend films

Silk fibroin/chitosan blend films were examined through IR spectroscopy to determine the conformational changes of silk fibroin. The effects of the fibroin/chitosan blend ratios (chitosan content) on the physical and mechanical properties were investigated to discover the feasibility of using these films as biomedical materials such as artificial skin and wound dressing. The mechanical properties of the blend films containing 10–40% chitosan were found to be excellent. The tensile strength, breaking elongation, and Young's modulus were affected by the chitosan contents of the blend films, which were also related to the density and degree of swelling. The coefficient of water vapor permeability of the blend films increased linearly with the chitosan content, and the values of 1000–2000 g m^?2 day^?1 were comparable to those of commercial wound dressings. Silk fibroin/chitosan blend films had good oxygen and water vapor permeabilities, making them useful as biomaterials. In particular, the blend film containing 40–50% chitosan showed very high oxygen permeability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 928–934, 2001     

聚乳酸/丝素共混膜的制备及其性能

用分子量为10万的聚乳酸（PLLA）对丝素膜进行改性,研究不同的聚乳酸加入量对丝素膜性能的影响,对聚乳酸/丝素共混膜进行了一系列表征。万能电子试验机的测试结果表明,经聚乳酸改性后,丝素膜的断裂强度,断裂伸长率有了较大的改善,当加入聚乳酸占丝素质量为5%时,丝素膜的强度可达到27.1 MPa,伸长率达4.4%; 改性后的丝素膜的亲水性有一定程度降低,溶失率则明显减小,透汽透湿性也有所提高;红外光谱测试表明,改性后的丝素膜含有较多的β构象成分。     

Structural changes and their effect on mechanical properties of silk fibroin/chitosan blends

Silk fibroin/chitosan blend films were prepared by the solvent casting method. Miscibility between silk fibroin and chitosan was examined by dynamic mechanical thermal analysis. Structural changes of silk fibroin by the addition of chitosan were investigated by IR spectroscopy. The conformational transition of silk fibroin from random coil form to β‐sheet structure induced by blending with chitosan resulted in the increase of crystallinity and density of the blend films. The blend film containing 30 wt % chitosan exhibited a maximum increase in crystallinity and density. It was found that the tensile strength and initial tensile modulus of blend films were greatly enhanced with increasing the chitosan content and showed a maximum value at the composition of 30 wt % chitosan. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2571–2575, 1999     

Development of a novel glucosamine/silk fibroin–chitosan blend porous scaffold for cartilage tissue engineering applications

Silk fibroin–chitosan blend is reported to be an attractive scaffold material for tissue engineering applications. In our earlier study, we developed a scaffold having an optimal silk fibroin–chitosan blend ratio of 80:20 and proved its potentiality for cartilage tissue engineering applications. Glucosamine is one of the major structural components of cartilage tissue. The present work investigates the effect of glucosamine components on the physicochemical and biocompatibility properties of this scaffold. To this end, varied amounts of glucosamine were added to silk fibroin–chitosan blend with the aim of improving various scaffold properties. The addition of glucosamine components did not show any significant change in physicochemical properties of silk fibroin–chitosan blend scaffolds. The composite scaffold showed an open pore structure with desired pore size and porosity. However, cell culture study using human mesenchymal stem cells derived from umbilical cord blood revealed an overall increase in cell supportive properties of glucosamine-added scaffolds. Cell viability, cell proliferation and glycosaminoglycan assays confirmed enhanced cell viability and proliferation of mesenchymal stem cells. Thus, this study demonstrated the beneficial effect of glucosamine on improving the cell supportive property of silk fibroin–chitosan blend scaffolds making it more potential for cartilage tissue regeneration. To the best of our knowledge, this is the first report on the study of glucosamine-added silk fibroin–chitosan blend porous scaffolds seeded with mesenchymal stem cells derived from umbilical cord blood.     

Fabrication and characterization of silk fibroin powder/polyurethane fibrous membrane

The blend fibrous membranes with the different mass ratio of silk fibroin (SF) powder to polyurethane (PU) were fabricated by electrospinning. The structure, morphology, mechanical properties, and surface wettabilities of the blend fibrous membrane are characterized by field‐emission scanning electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetry, dynamic mechanical thermal analysis, tensile testing, and contact angle measurements. The results show that the SF was uniformly distributed in the blend fibers. The mass ratio of SF to PU played an important role in influencing the structure and morphology of the blend fibers, and the optimum mass ratio was 5/5. With the increase in SF content in fibers, the fraction of SF in the surface of the SF/PU blend fibers and the crystallinity degree of PU increased, and the molecular orientation of PU along the fiber axis took place. The SF content regulated the hydrophilicity property of the membrane. The thermal stability and the dynamic storage modulus of the fibrous membrane decreased, and the phase separation between soft and hard segments of PU increased. Similarly, the stress at peak and Young's modulus of the fibrous membrane decreased gradually; the strain at peak first increased and then decreased. POLYM. ENG. SCI., 52:2025–2032, 2012. © 2012 Society of Plastics Engineers     

丝素/羧甲基壳聚糖复合材料的制备及其在丝绸文物加固中的应用

为了对脆弱丝绸文物进行保护修复，延长其寿命，本研究以丝素蛋白（SF）、羧甲基壳聚糖（CMCS）为原料，谷氨酰胺转氨酶为交联剂，制备丝素/羧甲基壳聚糖复合材料（SF/CMCS），并将其应用于老化丝绸加固保护。选用傅里叶变换红外光谱（FT-IR）、X-射线衍射仪（XRD）、测色配色分光光度计、扫描电镜（SEM）及伺服高低温控制拉伸机对老化丝绸加固前后效果进行表征。结果表明，与老化丝绸相比，SF/CMCS加固丝绸的颜色无明显变化，物理机械性能有明显提升，抗张强度和断裂伸长率分别提升了379.12%、14.12%%，且有一定的抗菌性。     

Fabrication of Chitosan/Silk Fibroin Composite Nanofibers for Wound-dressing Applications

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.     

壳聚糖/壳聚糖季铵盐交联共混阴离子交换膜的制备与性能研究

制备了一种新型阴离子交换膜——壳聚糖/壳聚糖季铵盐交联共混膜,并用FTIR对共混膜进行了初步表征;分析研究了不同交联度及配比对离子交换膜相关性能的影响;并运用测试膜电位的方法估算了离子的迁移数和选择透过度。研究表明,膜呈现较好的电化学性能,而膜的力学性能较差、含水量高、选择透过度稍低。HACC含量为25%,交联度为0.2%的共混膜干强与湿强分别为53.10 MPa和8.40 MPa,含水量66.4%,IEC为1.97 mmol/g,面电阻2.67Ω.cm2,离子迁移数为0.91,选择透过度为81.6%。