聚乙烯醇-羟乙基纤维素共混膜的制备及性能

以羟乙基纤维素(HEC)和聚乙烯醇(PVA)为原料,通过溶液浇铸共混制备不同含量的羟乙基纤维素/聚乙烯醇(HEC/PVA)共混膜,用傅立叶红外分析(FT-IR)、扫描电子显微镜(SEM)进行表征,并考察了HEC/PVA膜的力学性能.结果表明:当PVA质量含量为40％时,共混膜的力学性能较纯HEC有显著提高;温度越低膜的溶胀度越小,但当温度升到60℃以后,膜的溶胀度几乎不变化,说明膜在高温下尺寸的稳定性很好;随着温度的升高,膜的含水率不断增加,制备的共混膜的使用温度不要超过80℃.     

N–PBS/HEC共混物的性能研究

利用熔融缩聚的方法将N-甲基二乙醇胺与丁二酸和1,4-丁二醇共聚,制备含N的聚丁二酸丁二酯(PBS)共聚物(N–PBS),然后将其与纤维素衍生物羟乙基纤维素(HEC)进行溶液共混,制备了在水相中均匀分散的共混乳液,用流延成膜法制备了N–PBS/HEC共混膜。研究了N–PBS中—N(CH3)—基团的含量对N–PBS亲水性及共混膜性能的影响。结果表明,随着N–PBS中—N(CH3)—含量的增加,N–PBS极性增加,亲水性增强;相对于PBS,N–PBS与HEC的相容性得到改善,共混膜的热分解温度在300℃以上,热稳定性良好,其透过率和断裂伸长率也随着N–PBS中—N(CH3)—含量的增加而提高。     

超高粘度羟乙基纤维素的工业化生产

本文初步提出了超高粘度羟乙基纤维素（HEC）的观点，以美国联碳公司HEC－10的标准作为参考依据，优化工艺工业化生产了超高粘度羟乙基纤维素。     

壳聚糖-羟丙甲基纤维素共混膜的生物黏附性

把壳聚糖和羟丙甲基纤维素溶液相混合,通过相转化法成膜工艺制备壳聚糖和羟丙甲基纤维素共混膜,以猪大肠为黏附对象,考察在不同工艺条件下制得的CS/HPMC共混膜对猪大肠的黏附特征,研究结果表明:在越高温度下成膜,生物黏附性能越差;甘油的加入会使共混膜的生物黏附性能下降,当用量增加到0.2g时,生物黏附性能下降变得平缓;制膜液的浓度越高,所成膜的生物黏附性能越好;随着HPMC用量的增加,共混膜的生物黏附性能增强。并阐明CS/HPMC共混膜的生物黏附性能与在不同条件下成膜所得到的膜片材料结构和表面形态之间的关系。扫描电镜照片显示CS/HPMC共混膜的微观形貌呈多孔结构,这种结构对其生物黏附性能有影响。     

羟乙基纤维素接枝丙烯酰胺共聚物的合成及表征

以(NH4)2S2O8/Na2S2O3氧化还原体系为引发剂合成了羟乙基纤维素(HEC)接枝丙烯酰胺(AM)共聚物,后水解测量分子量并讨论反应温度、羟乙基纤维素含量、引发剂用量对分子量的影响,用红外光谱进行结构表征。     

羟乙基纤维素开发利用前景

对羟乙基纤维素（HEC）的用途及国内外生产状况进行了综述。     

羟乙基纤维素负载三苯基膦-钯催化剂的合成及其在Suzuki偶联反应中的应用

以羟乙基纤维素(HEC)为原料,首先合成三苯基膦功能化的羟乙基纤维素(HEC-OPPh3),进而与醋酸钯络合,合成了一种新型的羟乙基纤维素负载三苯基膦-钯催化剂(HEC-OPPh3-Pd)。热重分析(TGA)表明该催化剂在180℃以下稳定存在于空气中。进一步研究发现,羟乙基纤维素负载三苯基膦-钯催化剂于乙醇和水等比例混合溶剂中能有效催化Suzuki偶联反应。     

羟乙基纤维素开发利用前景

对羟乙基纤维素(HEC)的用途及国内外生产状况进行了综述.     

离子液体中疏水改性羟乙基纤维素的合成

采用大分子反应法,将疏水性单体l-溴代十二烷(BD)接枝到羟乙基纤维素(HEC)上,对羟乙基纤维素进行疏水改性,制备了疏水改性羟乙基纤维素(HMHEC)。研究了离子液体种类、反应温度、羟乙基纤维素浓度和BD用量对HMHEC性能的影响。最佳合成条件为:HEC浓度为3%(质量分数),溶解时间1 h,溶解温度100℃,反应时间2 h,反应温度80℃,BD用量为2 mL。在1-烯丙基-2-甲基-咪唑氯盐体系中合成的HMHEC性能好于在1-丁基-2-甲基咪唑氯盐中合成的HMHEC。     

HEC/CMC混合物水溶液流变性质的研究

采用旋转粘度计研究了HEC/CMC混合物水溶液的流变性质。结果表明 ,混合物体系中羧甲基纤维素 (CMC)含量高时 ,流动曲线符合幂律模型 ;羟乙基纤维素 (HEC)含量高时 ,则偏离幂律模型。同时还探讨了混合体系中溶液粘度的加和性以及温度依赖性     

Novel self‐supported natural and synthetic polymer membranes for air humidification

Novel self‐supported natural and synthetic polymer membranes of chitosan‐hydroxy ethyl cellulose‐montmorillonite (CS‐HEC‐MMT) and polyvinyl alcohol (PVA)‐polystyrene sulfonic acid (PSSA) are prepared by solution casting method followed by crosslinking. These membranes are employed for air humidification at varying temperatures between 30°C and 70°C and their performances are compared with commercial Nafion^® membranes. High water fluxes with desired humidified‐air output have been achieved for CS‐HEC‐MMT and PVA‐PSSA hybrid membranes at air‐flow rates of 1–10 slpm. Variation in the air/water mixing ratio, dew point, and relative humidity that ultimately results in desired water flux with respect to air‐flow rates are also quantified for all the membranes. Water flux values for CS‐HEC‐MMT are less than those for Nafion^® and PVA‐PSSA membranes, but the operational stability of CS‐HEC‐MMT membrane is higher than PVA‐PSSA and comparable with Nafion^® both of which can operate up to 70°C at repetitive cycles of humidification. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Formation of polyelectrolyte complexes between cellulose derivatives and their blood compatibility

Formation of polyelectrolyte complexes (PECs) between cellulose derivatives in aqueous solution and their blood compatibility were examined. To this end, two types of quaternary ammonium cellulose derivatives, Q-Cell and Q-HEC, were prepared by treating cellulose and hydroxyethyl cellulose (HEC), respectively, with glycidyl trimethylammonium chloride. Anionic derivatives were carboxymethyl cellulose (CMC) with different degrees of substitution (DS) and cellulose sulfate (CS). In vivo blood tests were made by a method of peripheral vein indwelling suture. The results showed that the complex formation of Q-Cell did not follow a stoichiometric reaction, but Q-HEC reacted stoichiometrically with CMC and CS. It was also found that water-insoluble cellulosic PECs are soluble in formic acid, showing that the cellulosic PEC films can be prepared from formic acid solutions. The blood tests revealed that by the criteria of the test method employed in this work, cellulosic PECs had a good blood compatibility.     

Transforming chromium containing collagen wastes into flexible composite sheets using cellulose derivatives: Structural,thermal, and mechanical investigations

Leather, footwear, and clothing industries produce significant quantity of chromium containing proteinaceous wastes. One of the major uses of these wastes is to convert them into sheets or boards. However, the previous methods could not provide flexible sheets with desired strength. Here, we describe a simple and efficient method for the preparation of flexible composite sheets using chromium containing collagenous wastes (CS) with the use of cellulose derivatives. The leather wastes have been partially hydrolyzed and converted into composite sheets under microwaves with the addition of 2‐hydroxyethyl cellulose (HEC) in varying concentrations from 2.5 to 20 wt%. A comprehensive strength as high as 3.14 ± 0.45 MPa with a softness of 3.8 ± 0.2 mm is achieved with the addition of 20 wt% HEC in the CS/HEC composite sheets. Scanning electron microscopic and mercury intrusion porosimetric analysis demonstrate the reduction in pores, especially micro pores (<50 μm), when the concentration of HEC is higher thereby showing improved interfacial adhesion of HEC onto CS. Infrared spectroscopy result indicates the presence of distinctive bands associated with both CS and HEC. There is also a reasonable increase in the thermal stability of the CS/HEC sheets as the content of HEC increases. Hence, the developed CS/HEC composite sheets were found to be flexible and have improved thermo‐mechanical properties, which are suitable for applications in leather product and allied industries. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Construction of Chlorine Labeled ZnO–Chitosan Loaded Cellulose Nanofibrils Film with Quick Antibacterial Performance and Prominent UV Stability

In this study, novel “green” and highly stable biocidal materials composed of cellulose nanofibrils (CNF) and ZnO–chitosan (ZnO–CS) hybrids are constructed by combing vacuum filtration and heat‐press processing without the use of any organic solvent. CNF/ZnO–CS films are soaked in a 10% sodium hypochlorite aqueous solution to endow antibacterial activity. The chlorinated CNF/ZnO–CS samples and chlorinated CNF/ZnO‐CS (CNF/ZnO‐CS‐Cl) possess quick antimicrobial activity against Staphylococcus aureus and Escherichia coli within 30 min of contact compared with CNF and CNF/ZnO–CS controls. The addition of ZnO endows the films with remarkable UV light stability. After exposure to a UV chamber for 24 h, the chlorine loadings on the prepared samples decrease to 0.13%, where 76% of the chlorine loss can be regained after rechlorination. Furthermore, cytotoxicity evaluations reveal the feasibility of the films for in vitro applications. The prepared rechargeable CNF/ZnO–CS–Cl films will have many promising antibacterial applications.     

纳米纤维素/壳聚糖/明胶复合膜的制备及其性能研究

以明胶（Gel）、壳聚糖（CS）、纳米纤维素（NCC）为原料,采用溶液共混法制备了不同NCC和CS质量比的纳米纤维素/壳聚糖/明胶复合膜。采用紫外-可见分光光度计、扫描电镜（SEM）、红外光谱仪（FT-IR）、X射线衍射仪（XRD）、热分析仪（TGA）和质构仪对所制备复合膜的透光性能、显微结构、化学结构、晶体结构、热学性能和力学性能进行了分析。结果表明：纳米纤维素、壳聚糖、明胶之间形成相互作用较强的网络结构。复合膜表面光滑,分散均匀,具有良好的相容性。随着纳米纤维素含量的增加,复合膜透光率呈下降的趋势。与壳聚糖膜相比,复合膜的热稳定性显著提高。当纳米纤维素与壳聚糖质量比为7：1时,复合膜拉伸强度最高可达到33 MPa,断裂伸长率可达到14.9%,吸水率最大值可达到341%。     

Dissolving states of cellulose and chitosan in trifluoroacetic acid

Chemical structures of cellulose and chitosan dissolved in trifluoroacetic acid (TFA) and those of cellulose and chitosan films cast from their TFA solutions were studied by ¹³C-NMR and infrared (IR) spectroscopy. Cellulose is trifluoroacetylated selectively at the C6–hydroxyl groups in the TFA solution, and chitosan is dissolved in TFA by forming amine salts with TFA at the C2–amine groups. IR analyses of cellulose films cast from its TFA–acetic acid solutions showed that partly trifluoroacetylated cellulose in the solution state turns to partly acetylated cellulose in the solid state during evaporation of the solvents in air by the ester interchange. Chitosan films cast from its TFA–acetic acid solutions still have the amine salts with TFA. These acetyl groups in cellulose films and TFA in chitosan films are removable by soaking the films in 1N NaOH at room temperature for 1 day.     

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。     

Physical properties of water‐borne polyurethane blended with chitosan

Water‐borne polyurethanes based on 4,4‐diphenylmethane diisocyanate, poly(butylene adipate), and chain extender N‐methyldiethanolamine (MDEA) that provided tertiary amine groups were synthesized. The polyurethane–chitosan (PU/CS) blends can be dissolved in the acetic acid and cast into films. The mechanical properties including tensile strength and elongation, as well as the water absorption and thermal properties of the PU/CS films were evaluated. The tensile strength increased with the increased amount of chitosan, but the elongation decreased accordingly. The chitosan in the blends promoted the water absorption. Chitosan was more thermally‐stable than PU, as shown in the thermal gravity analysis. Chitosan also had higher crystallinity, as demonstrated by differential scanning calorimetry. The blends were partial compatible mixtures, based on the data obtained from a dynamic mechanical analysis. Biocompatibility test was conducted utilizing immortalized rat chondrocytes (IRC). After IRC were seeded onto the PU/CS films for 1.5 and 120 h, the number of cells was counted and the morphology of cells was observed by light microscopy and scanning electron microscopy. Blends containing 30% chitosan had more cells attached initially. However, the blends containing more than 70% chitosan appeared to promote the cell proliferation. IRC were round on PU/CS films with more PU, but spread when the chitosan content in blends was higher. Overall, PU/CS films with more chitosan had better mechanical properties as well as biocompatibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2683–2689, 2007     

Mechanical reinforcement of chitosan using unzipped multiwalled carbon nanotube oxides

In this paper, unzipped multiwalled carbon nanotube oxides (UMCNOs), obtained by oxidation unzipping multiwalled carbon nanotubes (MWNTs) were used as novel nanofillers for mechanical reinforcement of chitosan (CS) matrix. The UMCNOs/CS nanocomposite films with different amounts of UMCNOs were fabricated by solution-casting the mixtures of UMCNOs and CS acetic acid aqueous dispersions. The structures and mechanical properties of the nanocomposite films were characterized by XRD, FT-IR, SEM, and tensile tests. The results demonstrated that UMCNOs could be homogeneously dispersed throughout the chitosan matrix. Compared to neat chitosan, the UMCNOs/CS nanocomposite films showed ～105.9% increase in tensile strength from 69.3 to 142.7 MPa, and ～165.3% increase in Young’s modulus from 2.6 to 6.9 Gpa with the incorporation of only 0.2 wt% of UMCNOs into the chitosan matrix.     

Electroactive Paper Actuator Made with Chitosan‐Cellulose Films: Effect of Acetic Acid

This paper introduces an electroactive paper (EAPap) prepared with cellulose and chitosan films. The fabrication process, performance test, and the effect of acetic acid dosage of the EAPap were investigated. For the fabrication of cellulose EAPap, cellulose fibers were dissolved into a solution using N,N‐dimethylacetamide and lithium chloride. The solution was cast and immersed in water to form a cellulose film, followed by casting chitosan/acetic acid and glycerol aqueous solutions on the cellulose film. A bending EAPap actuator was made by depositing thin gold electrodes on both sides of the cellulose film. The bending displacement of the EAPap actuators was evaluated with respect to voltage, frequency, humidity, and acetic acid dosage. An optimum mole ratio of the acetic acid and chitosan structure unit was found. Also, the effects of chitosan and acetic acid on the actuation behavior of the cellulose‐chitosan laminated films were investigated.