再生纤维素/壳聚糖/银纳米线抗菌复合膜制备及性能

以1-丁基-3甲基咪唑氯盐（[Bmim]Cl）为溶剂体系，通过微晶纤维素（MCC）溶解再生制备基膜，壳聚糖（CS）、银纳米线（AgNW）共混液包覆方法制备抗菌复合膜，通过FTIR、XRD、SEM和热重分析对复合膜的形貌和结构进行表征及对力学、光学、阻隔、抑菌等性能测试分析。结果表明，壳聚糖和银纳米线成功复合于纤维素基膜，与再生纤维素膜相比，当AgNW质量分数为0.5%时，复合膜的拉伸强度提升了12.2%，透光率保持在89.82%，氧气透过率下降了86.7%，且对大肠杆菌具有良好的抑制作用，制备出一种力学性能、光学性能、阻隔性能、抗菌性能优异的可降解纤维素/壳聚糖/银纳米线抗菌复合膜。     

明胶/纳米微晶纤维素共混复合膜的逾渗研究

以共混的方法制备了明胶/纳米微晶纤维素复合膜。测定了不同纳米微晶纤维素质量分数(0%～1%)下复合膜的抗拉强度(2.3～14.8 MPa)、断裂伸长率(55%～13%)和热缩性(3.5%～1.4%)。当添加纳米微晶纤维素(NCC)到一定量时复合膜的抗拉强度、断裂伸长率和热缩性的数值都发生了突变。结果表明,明胶/纳米微晶纤维素共混复合膜存在逾渗现象,逾渗阈值为质量分数0.6%NCC。     

一种壳聚糖/纳米纤维素复合膜的制备及性能研究

采用流延法制备了壳聚糖/纳米纤维素复合膜。探究了纳米纤维素和壳聚糖不同质量比时复合膜的各项性能:表征了膜的形貌,测定了复合膜的机械性能、热收缩性、吸水性、降解性、热稳定性。结果表明:复合膜中壳聚糖和纳米纤维素混合均匀,纳米纤维素和壳聚糖质量比为10%的复合膜吸水及降解性好,CNC质量比为50%时,膜拉伸强度最大,比单纯壳聚糖膜提升了154%。     

纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜性能与细胞相容性

以椰壳纤维为原料，制备了纳米纤维素晶须，用硅烷偶联剂对纳米纤维素晶须进行改性，将改性后纳米纤维素晶须与壳聚糖、聚乙烯醇共混，采用溶液浇铸法制备了改性纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜。采用FTIR、DSC、TG、XRD和SEM对改性纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜的结构、热性能、结晶行为和形貌进行表征与分析，对复合膜的力学性能和水接触角进行测试，将成纤维细胞L929接种到复合膜上，对其进行细胞相容性实验。结果表明，添加改性纤维素晶须，能够使壳聚糖/聚乙烯醇复合膜的热性能、结晶行为和力学性能提高，成纤维细胞在复合膜上具有较好的黏附和生长，制备的纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜具有良好的综合性能和细胞相容性。     

纳米微晶纤维素增强羟丙基纤维素复合膜的力学性能和透光度的研究

采用酸碱处理竹原纤维并辅以超声分散制备纳米微晶纤维素（NCC）,采用溶液浇铸/水分挥发的成型方法制备了纳米微晶纤维素增强羟丙基纤维素（HPC）全纤维素纳米复合膜.研究了NCC/HPC复合膜的力学性能、透光度以及热稳定性.随着纳米微晶纤维素含量的增加,复合膜的拉伸强度、拉伸模量、储能模量和热稳定性逐渐增大,与纯羟丙基纤维素膜相比,当纳米微晶纤维素质量分数为60％时,纳米复合膜的拉伸强度提高了8.5倍,拉伸模量提高了3.9倍,储能模量提高了3.7倍,而NCC/HPC复合膜的透光度没有出现明显的下降.     

交联壳聚糖/蒙脱土复合膜的制备及性能研究

以壳聚糖（CS）为基质材料，蒙脱土（MMT）为填料，采用戊二醛（GA）交联改性并结合溶液插层法制备了交联壳聚糖/蒙脱土（CS/GA/MMT）复合膜。通过扫描电子显微镜、X射线衍射仪、红外光谱仪及热重分析仪对复合膜的结构进行了表征，考察了MMT用量对复合膜的吸水性能、水蒸气阻隔性能和力学性能的影响。结果表明，交联改性CS可提高CS膜的耐水性，CS/GA膜的吸水率较CS膜降低了9.6 %；MMT可提高复合膜的耐水性、水蒸气阻隔性能、力学性能和热稳定性；当MMT的用量为CS质量的5 %时，复合膜的各项性能较好，吸水率、水蒸气透过率和断裂伸长率较CS膜分别降低了37.3 %、36.7 %和41.9 %，且拉伸强度提高了160.5 %。     

纳米纤维素/羟丙基甲基纤维素复合膜的制备与性能研究

为开发纤维素基可降解膜材料,以酸解微晶纤维素的方式制备了纳米纤维素(NCC),并以其为增强相,羟丙基甲基纤维素(HPMC)为成膜基质,甘油为增塑剂,通过流延法制备了复合膜。考察了NCC质量分数对复合膜性能的影响,所得NCC的产率为37. 42%,结晶度较微晶纤维素(MCC)有所提高。复合膜的形貌、结晶结构、化学键分析结果显示,NCC在基质中均匀分散,NCC与HPMC之间存在着较强的相互作用。性能测试结果表明,当NCC质量分数为8%时,复合膜的抗拉强度提高了50. 61%,水蒸气透过率下降了15. 27%,阻氧性能提高了36. 04%;因此,NCC可有效提高HPMC膜的力学性能和阻隔性能,且对其透光率也有所改善。     

醋酸纤维素/壳聚糖复合膜制备与性能优化

为拓展醋酸纤维素(CA)在可降解包装材料中的应用,采用溶液共混法制备了醋酸纤维素(CA)和壳聚糖(CS)复合膜,研究了CS含量对CA/CS二元复合膜性能的影响。通过观察并分析复合膜的形貌、断面结构、化学键发现,CS能够充分结合膜内外的孔隙结构,两者之间强烈的相互作用增强了复合膜的各项性能。性能测试结果表明,当CS含量为10%时,复合膜的力学性能达到最大,断裂伸长率及抗拉强度分别增加12.37%和38.62 MPa,降解损失率提高了50.14%。同时,抑制了大肠杆菌及金黄色葡萄球菌的生长,抗菌率最高能够达到73.9%和54.6%。因此,CS在提高CA膜的力学性能和降解性能的同时,还赋予了复合膜优异的抗菌性。     

壳聚糖/聚羟基丁酸戊酸共聚酯生物降解复合膜的制备

以冰乙酸为溶剂,将壳聚糖（CS）与聚3-羟基丁酸-co-3-羟基戊酸共聚酯（PHBV）采用共混流延法制备成CS/PHBV生物降解复合膜。采用扫描电镜、傅里叶变换红外光谱对复合膜进行了表征,并研究了不同质量比CS/PHBV复合膜的力学性能、透氧性能、热稳定性以及生物降解性能。结果表明：随着壳聚糖含量的增加,复合膜断面密实,蜂窝状结构消失,复合膜中羟基和酯基增多;当m_CS∶m_PHBV为3∶1时,CS/PHBV生物降解复合膜的拉伸强度与弹性模量达到最大值,分别为3.57和26.84 MPa;当m_CS∶m_PHBV为4∶1时,复合膜的透氧系数最小,为27.7×10^-15 cm³·cm/（cm²·s·Pa）;同时,壳聚糖的加入,提高了CS/PHBV复合膜的生物降解性。     

超声波辅助纤维素酶水解制备纳米纤维素

以人纤浆为原料，利用超声波辅助纤维素酶水解制备纳米纤维素（NCC），在单因素试验基础上，采用正交试验优化NCC的制备条件，并通过透射电镜（TEM）、X射线衍射（XRD）、红外光谱（FT-IR）、热重（TG）和Zeta电位测定对NCC的结构和性能进行了分析与表征。研究结果表明：NCC的最佳制备条件为酶用量为人纤浆质量的7%、50℃条件下酶解反应10 h，此时纳米纤维素的得率可达62.3%。TEM表征显示制备的纳米纤维素呈短棒状，纳米纤维素之间相互交织形成网络结构；XRD分析表明纳米纤维素的晶体结构并未发生改变，仍为纤维素Ⅰ型，结晶度由人纤浆的54.2%增大到73%；FT-IR分析显示纳米纤维素仍保持天然纤维素的化学结构；热重分析表明纳米纤维素的热稳定性较纤维素原料显著提高；Zeta电位测试结果表明纳米纤维素在水介质中具有良好的分散稳定性。     

Preparation of gelatin-based films modified with nanocrystalline cellulose

Gelatin is a natural biological macromolecule derived from the collagen in the connective tissue of the skin, bone and other tissues. It has been widely used in medicine, food and industrial production and other fields for easy molding, excellent compatibility and biodegradability. However, physical and chemical disadvantages impede its further application, seriously. Therefore, modification of the gelatin films becomes more and more important. In this study, the gelatin/nanocrystalline cellulose (NCC) composite films were prepared by casting method with 4% glycerol as plasticizer. The effect of NCC on the properties of the composite films was investigated by the characterization of its morphology and mechanical, thermal, and optical properties and water adsorption. The results showed that mechanical, thermal stability and water absorption properties of the gelatin/NCC composite film were obviously improved. The composite films showed the highest tensile strength (13.56?±?0.25 MPa) when the mass concentration of NCC was 0.6%. Adding NCC to gelatin benefited the thermal stability of composite films. The gelatin/NCC composite film of 0.4% NCC had the highest melting transition temperature (138.9 °C). The composite films exhibited the lower water absorption (271.1%) when mass concentration of NCC was 1.0%. Thus, these results indicated that NCC could affect the properties of gelatin-based composite films, and showed it has potential for application in food packing.     

Influence of the polymorphism of cellulose on the formation of nanocrystals and their application in chitosan/nanocellulose composites

In this study, we evaluated the physicochemical properties of the chitosan/nanocellulose composites. Wide‐angle X‐ray scattering was applied to define the supermolecular structure of the materials, the laser diffracting technique was used to characterize the particle sizes, and scanning electron microscopy was used to evaluate the morphologies of the samples. The tensile properties of the composite films were also determined. Cellulose pulp was mercerized with 16% sodium hydroxide to give only cellulose II. Cellulose I and cellulose II were subsequently hydrolyzed with 64% sulfuric acid. As a result, nanocellulose I (NCC I) from cellulose I and nanocellulose II (NCC II) from cellulose II were produced. The mercerization of cellulose pulp contributed to a significant particle size reduction; more than 50% of the particles of the NCC II sample and only 36% of the particles of the NCC I sample were smaller than 100 nm. Chitosan composite films containing 5, 10, and 20% w/w of nanocelluloses were prepared by a solvent casting method. This was the first study investigating the influence of the crystallographic forms of cellulose on the formation of nanocrystals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42864.     

Preparation and characterization of artificial skin using chitosan and gelatin composites for potential biomedical application

A bioadhesive wound-dressing material based on the combination of gelatin and chitosan with a proper ratio was developed and successfully applied in biomedical fields. The composite films were prepared with increase in chitosan concentration in a fixed amount of gelatin and were evaluated for mechanical stability (e.g., tensile strength, elongation-at-break), water and buffer uptake capacity, water and buffer aging, molecular structure, morphology, thermal stability, and for biological properties (e.g., antimicrobial activity, cytotoxicity, in vivo wound-healing performance). It is noteworthy that the 10:3 (gelatin:chitosan) composite films showed the best physico-mechanical, thermal, and antimicrobial properties among the other ratios blend films. The improved mechanical and thermal stability of the 10:3 composite film suggested its promising use as carrier for controlled release drug. The composite film was evaluated using a rat model for in vivo tests to ascertain the applicability of the proper ratio of the chitosan and gelatin in the film for best wound-healing activity. Wound sites dresses with gelatin/chitosan composite films showed excellent rapid healing of the wound surface than those dressed with eco-plaster and gauze. Within a day after dressing with 10:3 composite film, the healing efficiency was found to be 80?%.     

PMMA/棉花纤维素复合薄膜的制备及性能

为改善聚甲基丙烯酸甲酯(PMMA)的热性能和力学性能,以经过预处理的棉花纤维素为增强体,将PMMA与棉花纤维素溶液按不同比例混合,利用溶液浇铸法制备PMMA/棉花纤维素复合薄膜,并利用热重分析、透光性分析以及拉伸性能测试研究了不同棉花纤维素含量的PMMA/棉花纤维素复合薄膜的性能。结果表明,与PMMA薄膜相比,PMMA/纤维素复合薄膜的热稳定性和力学性能均有所提升,PMMA/纤维素复合薄膜的热分解温度提高8.3%;随着棉花纤维素含量从0增加到15%,拉伸强度从10.53 MPa提升到55.95 MPa,最高提升了431%。此外,复合薄膜的光透过率随着棉花纤维素含量的增加而降低。当棉花纤维素含量为7.5%时,复合薄膜不仅具有良好的力学性能,而且具有较高的透光率,综合性能较好。     

Preparation of treelike and rodlike carboxymethylated nanocellulose and their effect on carboxymethyl cellulose films

In this work, carboxymethyl cellulose (CMC) with low substitution degree, followed by different posttreatments, was applied to prepare treelike CMC nanofibrils (CMCNFs) and rodlike CMC nanocrystals (CMCNCs), and their performance in CMC composite film was evaluated simultaneously. From transmission electron microscopy results, it was found that the treelike CMCNCFs exhibited a lager aspect ratio compared to the rodlike CMCNCs. As for reinforcing CMC film, 4 wt% was the best adding amount, at this time, the tensile strength of CMC/CMCNFs and CMC/CMCNCs composite films was increased by 72.1% and 47.3%, respectively. Moreover, adding these nanofillers to CMC also could enhance the thermal stability of composite films slightly, while the transmittance of composite films was reduced at the same time. In addition, CMC/CMCNFs film was designed as a packaging box to determine its performance. Therefore, this study could reveal the differences of properties for composites with different types of nanocellulose and provide a foundation for further application of nanocellulose.     

Preparation,characterization, antibacterial properties,and hemostatic evaluation of ibuprofen‐loaded chitosan/gelatin composite films

Ibuprofen‐loaded chitosan/gelatin (CS/GE) composite films were fabricated in this work. The morphology of the composite film was investigated using scanning electron microscopy. The functional groups of the composite film before and after crosslinking were characterized using Fourier transform infrared spectroscopy. Meanwhile, the mechanical properties, antibacterial performance, cytocompatibility, and hemostatic activity of the composite films were investigated. The results show that the amount of CS affected the mechanical properties and liquid uptake capacities of the composite films. The composite film showed better bactericidal activity against Staphylococcus aureus than Escherichia coli. In vitro drug‐release evaluations showed that crosslinking could control the drug‐release rate and period in wound healing. Both types of CS/GE and drug‐loaded CS/GE composite films also showed excellent cytocompatibility in cytotoxicity assays. The hemostatic evaluation indicated that the composite film crosslinked by glutaraldehyde in rabbit livers had a dramatic hemostatic efficacy. Therefore, ibuprofen‐loaded CS/GE composite films are potentially applicable as a wound dressing material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45441.     

Enhancing the mechanical and barrier properties of chitosan/graphene oxide composite films using trisodium citrate and sodium tripolyphosphate crosslinkers

This study investigated the effect of ionic crosslinking on the mechanical, barrier, and optical properties of chitosan (CS) and CS/graphene oxide (CSGO) composite films using trisodium citrate (CIT) and sodium tripolyphosphate (TPP) solutions of different concentrations (0.5, 1.0. 2.0, and 3.0% w/v). Successful crosslinking was confirmed by Fourier-transform infrared spectroscopy. The hydrophilicity and light transmittance decreased significantly (p < 0.05) with the increase in concentration of both crosslinking agents. The CS films crosslinked with 3.0% w/v TPP exhibited significant (p < 0.05) improvements in barrier properties, achieving a 51% decrease of water vapor permeability and 59% decrease in oxygen permeability, in comparison to neat CS film. In addition, TPP-crosslinked CSGO films experienced an 82% and 42% improvement in tensile strength and elongation at break, respectively. Overall, crosslinked CS and CSGO films possess significantly improved properties and have great potential to be further studied as food packaging materials.     

聚乳酸–壳聚糖–茶多酚复合膜的制备及其性能

为研究壳聚糖(CS)、茶多酚(TP)和聚乳酸(PLA)3种物质所得复合膜的性能效果,采用流延成膜法,制备不同CS与TP质量比的PLA–CS–TP复合膜。通过测试纯PLA膜及各复合膜的密度、力学性能、热封性能、水蒸气透过率和溶解度等指标,对比分析了复合膜的综合性能,研究其实用价值。结果表明,相比纯PLA膜,CS与TP的加入使复合膜的密度和拉伸性能明显降低,但显著提高了复合膜的热封强度、水蒸气透过率和溶解度。当CS与TP质量比为3/7时,热封强度最高,比纯PLA膜提高了245.72%;当CS与TP质量比为5/5时,水蒸气透过率最高,比纯PLA膜提高了28.59%;当CS与TP质量比为1/9时,溶解度最高,比纯PLA膜提高了758.04%。复合膜具有较好的热封性、透湿率和溶解度,在食品包装领域有较好的应用潜力,可使无花果在5℃下的保存期由2 d延长至13 d以上。