辉光放电电解等离子体法制备羧甲基纤维素/聚乙二醇/丙烯酸高吸水性复合材料及其溶胀性能

在水溶液中,以丙烯酸(AA)、羧甲基纤维素(CMC)和聚乙二醇(PEG)为原料,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,用辉光放电电解等离子体(GDEP)引发制备羧甲基纤维素/聚乙二醇/丙烯酸(CMC/PEG/AA)高吸水性复合材料。采用红外光谱、X射线衍射、扫描电镜和热重分析对复合材料的结构、形貌和热稳定性进行了表征;研究了复合材料在蒸馏水、雨水、0.9%NaCl溶液、黄河水和自来水中的溶胀行为。结果表明,CMC、PEG和AA发生接枝共聚形成高吸水性复合材料,组分间相容性好,表面出现深浅不均匀的沟壑、孔洞和凹槽,热稳定性能良好;复合材料在蒸馏水、雨水和0.9%NaCl溶液中的最大平衡溶胀率分别约为935 g/g、689 g/g、78 g/g;在黄河水和自来水中溶胀动力学行为表现出过溶胀平衡特性,即材料先发生溶胀,达最大值后再逐渐消溶胀到平衡。     

具有半互穿网络结构的电场响应性水凝胶正渗透脱盐性能

为了提高凝胶驱动正渗透(FO)脱盐过程的性能,利用互穿聚合物网络技术制备一种具有半互穿网络的电场响应性水凝胶聚(2-丙烯酰胺基-2-甲基丙磺酸-co-丙烯酰胺)/羧甲基纤维素钠(P(AMPS-AM)/CMC)用作新型汲取剂。使用红外光谱和扫描电镜表征其化学结构和形貌,考察其在水中的溶胀性及在电场刺激下的响应性,并探究其在FO脱盐过程中的性能。结果表明,P(AMPS-AM)/CMC呈现孔洞结构;溶胀过程符合二级溶胀动力学模型且理论平衡溶胀度为181.5 g/g;在15 V电压刺激下具有明显的消溶胀性。在FO试验中,与未经CMC改性的P(AMPS-AM)相比,P(AMPS-AM)/CMC产生类似的初始水通量但其在15V电压刺激下的水回收率是前者的1.9倍,且连续3次再生后水回收率仅下降7.97%。此外,与已报道的水凝胶汲取剂相比,P(AMPS-AM)/CMC不仅可获得较高的水通量而且在水回收率上具有一定的优势。     

细菌纤维素/聚乙烯醇/胶原蛋白复合膜的制备及表征EI北大核心CSCD

以细菌纤维素(BC)膜为基材,聚乙烯醇(PVA)和胶原蛋白(COL)为增强材料制备了复合膜,并采用碳化二亚胺(1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC·HCl)为交联剂对制备的复合膜进行交联处理。利用红外光谱、扫描电镜、X射线衍射、热重分析、拉伸强力、吸水性能等测试手段对复合膜的化学结构、微观结构及性能进行了研究。研究表明,PVA和COL均匀地被吸附并沉积于BC的三维网络结构中,或包裹在BC纤维上;与BC/PVA/COL复合膜相比,采用EDC·HCl交联后的复合膜的溶胀性能降低,热降解稳定性和拉升强力得到了增强,断裂延伸率略有下降;但相对于BC膜来说,复合膜的拉伸强度和断裂伸长率都有较大程度的提升。     

细菌纤维素/聚乙烯醇/胶原蛋白复合膜的制备及表征

以细菌纤维素(BC)膜为基材,聚乙烯醇(PVA)和胶原蛋白(COL)为增强材料制备了复合膜,并采用碳化二亚胺(1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC·HCl)为交联剂对制备的复合膜进行交联处理。利用红外光谱、扫描电镜、X射线衍射、热重分析、拉伸强力、吸水性能等测试手段对复合膜的化学结构、微观结构及性能进行了研究。研究表明,PVA和COL均匀地被吸附并沉积于BC的三维网络结构中,或包裹在BC纤维上;与BC/PVA/COL复合膜相比,采用EDC·HCl交联后的复合膜的溶胀性能降低,热降解稳定性和拉升强力得到了增强,断裂延伸率略有下降;但相对于BC膜来说,复合膜的拉伸强度和断裂伸长率都有较大程度的提升。     

多孔聚甲基丙烯酸甲酯与羟基磷灰石复合材料的制备及表征

在传统聚甲基丙烯酸甲酯(PMMA)制备的基础上,以羧甲基纤维素(CMC)和羟基磷灰石(HA)分别作为成孔剂和生物活性填料,制备多孔PMMA和多孔PMMA/HA复合材料,并用热电偶、显微CT、MTS材料试验系统和扫描电镜等比较改良后的PMMA合成物与传统PMMA最高聚合温度、抗压强度、弹性模量以及体外矿化能力等。结果显示:CMC水凝胶能显著降低传统PMMA聚合时的产热,也能使致密PMMA形成相互联通的孔径结构从而使其力学特性与人松质骨更匹配。HA颗粒的载入不会影响多孔PMMA支架的力学性能,但却能显著提高所形成复合材料的体外矿化能力。改良后的多孔PMMA/HA复合材料作为骨缺损修复材料具有良好的应用前景。     

取代度和改性MMT对纤维素基高吸水性纳米复合材料性能的影响

以麦秸秆为原料制备羧甲基纤维素(CMC),采用水溶性丙烯酸类单体对其接枝共聚,并添加不同有机季铵盐插层改性的蒙脱土(MMT),通过原位插层聚合制备CMC/丙烯酸类聚合物/OMMT高吸水性纳米复合材料。考察了碱和氯乙酸用量对CMC取代度和增重率的影响,探讨了CMC取代度与产物接枝率、接枝效率、吸水率之间的关系,分析了不同季铵盐改性MMT对材料性能的影响。通过红外光谱、X射线衍射等对纳米复合材料的结构进行表征,结果表明,在OMMT存在的条件下,CMC与丙烯酸类单体成功发生了接枝聚合;随着季铵阳离子碳链取代基的体积增大,改性蒙脱土的层间距越大;所制备的纳米复合材料属于剥离型纳米复合材料。     

添加剂对去乙酰基魔芋葡甘聚糖膜力学性能的影响

按 L8 (4× 2 4)正交试验设计制备魔芋葡甘聚糖膜 ,研究了 CMC、山梨醇和甘油等添加剂以及溶胀时间对魔芋葡甘聚糖膜拉伸强度和耐折度两个力学性能指标的影响。极差分析表明 ,各试验因素对KGM膜两个力学性能指标的影响有程度的差异。方差分析表明 ,溶胀时间、山梨醇与甘油对 KGM膜拉伸强度的影响均极显著 (P<0 .0 1 ) ,CMC的影响显著 (P<0 .0 5 ) ;CMC和甘油对膜耐折度的影响均极显著 (P<0 .0 1 ) ,溶胀时间、山梨醇的影响不显著 (P>0 .0 5 )。     

载当归羧甲基纤维素-海藻酸钠复合微球的制备和表征

采用W/O乳液法,在不同条件下,用Ca2+交联和戊二醛交联制备了羧甲基纤维素(CMC)-海藻酸钠(SA)复合微球。SEM结果显示,当m(CMC)∶m(SA)=1∶5、温度为60℃时,球形较好。采用FT-IR分析了复合微球的化学结构。对复合微球的溶胀率、药物包封率进行表征,结果显示复合微球在磷酸缓冲液中的溶胀率达到700%,且溶胀速度快。该复合微球对当归(ASD)具有较好的缓释作用。     

氧化石墨烯/羧甲基纤维素钠/海藻酸钠复合材料的制备与性能研究

采用改进的Hummer法和超声波剥离法制备了纳米氧化石墨烯悬液,再将其与羧甲基纤维素钠、海藻酸钠复合制备了氧化石墨烯/羧甲基纤维素钠/海藻酸钠(GO/CMC/SA)复合材料,并通过吸水性实验和拉伸实验方法对其结构和性能进行了研究。结果表明,添加GO和CMC可显著提高GO/CMC/SA复合材料的力学性能和吸水性,当GO含量为7%,CMC含量为15%时,复合材料的干态拉伸强度最大达到124.5MPa,复合材料湿态拉伸强度最大达到31.0MPa;吸水率达到196%,在生物医学领域具有较大的应用潜力。     

细菌纤维素/聚乳酸互穿网络复合材料的结晶与熔融

为了研究细菌纤维素(BC)网络结构对聚乳酸(PLA)结晶与熔融过程的影响,以PLA为基体,BC为增强体,通过PLA-三氯甲烷溶液与BC-无水乙醇分散液的共混扩散制备了具有互穿网络结构的BC/PLA生物复合材料。采用SEM、偏光显微镜(POM)、DSC和莫志深(MO)模型研究了复合材料的微观形态、球晶形貌、非等温结晶动力学和熔融行为。结果表明:采用溶液共混扩散法可得到以BC为骨架、PLA缠绕其表面的互穿网络结构的复合材料。随降温速率增加,BC/PLA复合材料的结晶温度、熔融温度和相对结晶度均下降。BC可作为异相成核剂,适量添加可同时提高BC/PLA复合材料的结晶速率和相对结晶度,细化球晶尺寸。MO模型可较好地描述BC/PLA复合材料的非等温结晶动力学行为。     

Bacterial cellulose-poly(vinyl alcohol) nanocomposites prepared by an in-situ process

Bio-nanocomposites were prepared by an in-situ growth process through the direct addition of poly(vinyl alcohol) (PVA) into the Acetobacter xylinum inoculated medium and compared with composites made by impregnation of bacterial cellulose (BC) gels with a PVA solution. Mechanical property tests showed that the presence of PVA in the BC acts as a plasticizer, interrupting hydrogen bonding between cellulose fibrils within the BC network. This resulted in a reduction in Young's modulus and an increase in toughness compared to pure BC sheet, especially for in-situ grown samples. Interestingly, the small amount of added PVA turns the BC sheet into optical transparent nanocomposite films with excellent mechanical properties.     

Carboxymethylated-bacterial cellulose for copper and lead ion removal

Carboxymethylated-bacterial cellulose (CM-BC) was synthesized by Acetobacter xylinum by adding water-soluble carboxymethylated cellulose (CMC) in the culture medium. The CM-BC was examined for the removal of copper and lead ions from aqueous solution compared with BC. The effects of performance parameters such as pH, adsorbent dose, contact time on copper and lead ion adsorption were analyzed. Both BC and CM-BC show good adsorption performance at optimized pH 4.5. Compared with BC, CM-BC performs better adsorption, with the value of 9.67 mg (copper)/g, 22.56 mg (lead)/g for BC and 12.63 mg (copper)/g, 60.42 mg (lead)/g for CM-BC, respectively. The adsorption rate closely follows pseudo-second-order rate model and the adsorption isotherm data well follows the Langmuir model.     

Optical nanocomposites prepared by incorporating bacterial cellulose nanofibrils into poly(3-hydroxybutyrate)

A biocompatible polymeric nanocomposite was prepared by incorporating bacterial cellulose (BC) into a poly(3-hydroxybutyrate) (PHB) matrix. The transparency of the PHB/BC nanocomposite was high due to the homogeneous nano-sized spherulite and nanofibril of PHB and BC, which are smaller than the wavelength of visible rays. The X-ray diffraction patterns of the PHB in the nanocomposite film showed peaks corresponding to the crystallized PHB. The thermal stability of PHB in the nanocomposite film has been improved. The morphology studies showed that the PHB molecules filled vacancies between BC nanofibrils. An increase in the mechanical properties was observed by incorporating the BC into the PHB matrix. This PHB/BC nanocomposite can be considered for various applications, such as display devices, tissue engineering scaffold, and food packaging, because of its improved mechanical properties along with biodegradability and biocompatibility.     

Influence of reduced graphene oxide on mechanical behaviors of sodium carboxymethyl cellulose

Sodium carboxymethyl cellulose/reduced graphene oxide (NaCMC/rGO) nanocomposite films were prepared by a simple solution mixing-evaporation method. The NaCMC/rGO nanocomposite films were characterized and compared with sodium carboxymethyl cellulose/graphene oxide (NaCMC/GO) nanocomposite films. The stability of the rGO dispersion, and the structural and mechanical properties of the composite films were investigated by UV–Vis spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and using a universal testing machine (UTM). The results revealed that CMC and rGO were able to form a homogenous mixture. Compared with pure CMC, the tensile strength and Young's modulus of the CMC/rGO nanocomposite films were considerably enhanced (by 72.52% and 131.79%, respectively) upon incorporation of 2 wt% rGO.     

CS/ CMC 二元增强系统的配制及应用

以阳离子淀粉(CS)和羧甲基纤维素(CMC)为纸张的二元增强系统,研究了其对纸张的增强程度。研究结果表明,单独添加占绝干纤维质量2.2%的阳离子淀粉时,纸样抗拉指数提高了6.4%;单独添加占绝干纤维质量4.4%的羧甲基纤维素时,纸样抗拉指数提高了2.6%;当阳离子淀粉和羧甲基纤维素复配使用时,且添加总量为2.2%,配比为10∶0.8时,纸样抗拉指数增幅达到15%以上。     

Synthesis and characterization of cellulose acetate–calcium carbonate hybrid nanocomposite

A hybrid nanocomposite composed of calcium carbonate (CaCO₃) and cellulose acetate (CA) was fabricated by bubbling CO₂ gas into the mixture of CA and Ca(OH)₂ solution. Cellulose acetate–calcium carbonate (CA–CC) nanocomposite was characterized by spectral, thermal and optical methods. FTIR and XRD analysis confirmed the formation of the hybrid nanocomposite and XRD confirmed the formation of CaCO₃ with calcite polymorph. Thermal analysis showed CA–CC nanocomposite has better thermal stability than pristine CA. The CaCO₃ nanoparticles were in sphere shape with 100–1000 nm diameter.     

Synthesis and characterization of mechanically strong carboxymethyl cellulose–gelatin–hydroxyapatite nanocomposite for load-bearing orthopedic application

Novel three-dimensional hybrid polymer–hydroxyapatite nanocomposites have been developed as load-bearing synthetic bone graft through in situ mineralization process, using natural polymers carboxymethyl cellulose (CMC) and gelatin (Gel) as matrix. This process is simple and does not involve any chemical cross-linker. Detailed structural and physicochemical characterization of the samples disclosed that incorporation of gelatin with CMC assists the formation of CMC-Gel polymeric network of new conformational structure through non-covalent interactions (H-bond). The formation of hydroxyapatite (HA) in this polymeric network was occurred in such a fashion that the HA serves as bridging molecule which strengthen the polymeric network more and formed a mechanically strong three-dimensional CMC-Gel-HA nanocomposite. The synthesized CMC-Gel-HA nanocomposites have compressive strength and modulus in the range of 40–86 MPa and 0.4–1.2 GPa, respectively, analogous to human cancellous as well as cortical bone. In vitro cell interaction of the synthesized nanocomposites with osteoblast-like MG-63 cells has been evaluated. Results showed that synthesized CMC-Gel-HA nanocomposite promote cells for high alkaline phosphatase activity and extracellular mineralization. Extracellular mineralization ability of nanocomposite was investigated by alizarin red staining and von Kossa staining. Biodegradable nature and bone apatite formation ability of CMC-Gel-HA nanocomposite under simulated physiological environment were investigated by different characterization processes. Results indicated that the synthesized CMC-Gel-HA nanocomposite has great potential to be used as regenerative bone graft in major load-bearing region.     

羟基磷灰石／细菌纤维素纳米复合材料的制备与热力学性能表征

摘要通过仿生途径制备了模拟天然骨成分的羟基磷灰石／细菌纤维素（hydroxyapatite/bacterial cellulose,HAp/BC）纳米复合材料,使用TGA（thermo-gravimetric analysis）, DSC（differential scanning calorimetry）和DMA（dynamic mechanical analysis）测试方法对复合材料进行了热力学表征,以此来了解复合材料的成分组成、热稳定性和热力学行为．实验结果表明,纳米复合材料的成分与天然骨相似,并且热稳定性与纯BC相比有所提高;纳米复合材料在热分解时存在复杂的吸热放热现象;由于HAp的加入,与BC相比,复合材料的玻璃化转变温度向高温区域移动．     

Structural,optical, and dielectric characteristics of copper oxide nanoparticles loaded CMC/PEO matrix

Journal of Materials Science - Polymer nanocomposite films were prepared using the casting method through filling a polymer mixture of carboxymethyl cellulose (CMC) and polyethylene oxide (PEO)...     

Composites of Bacterial Cellulose and Small Molecule‐Decorated Gold Nanoparticles for Treating Gram‐Negative Bacteria‐Infected Wounds

Bacterial infections, especially multidrug‐resistant bacterial infections, are an increasingly serious problem in the field of wound healing. Herein, bacterial cellulose (BC) decorated by 4,6‐diamino‐2‐pyrimidinethiol (DAPT)‐modified gold nanoparticles (Au‐DAPT NPs) is presented as a dressing (BC‐Au‐DAPT nanocomposites) for treating bacterially infected wounds. BC‐Au‐DAPT nanocomposites have better efficacy (measured in terms of reduced minimum inhibition concentration) than most of the antibiotics (cefazolin/sulfamethoxazole) against Gram‐negative bacteria, while maintaining excellent physicochemical properties including water uptake capability, mechanical strain, and biocompatibility. On Escherichia coli‐ or Pseudomonas aeruginosa‐infected full‐thickness skin wounds on rats, the BC‐Au‐DAPT nanocomposites inhibit bacterial growth and promote wound repair. Thus, the BC‐Au‐DAPT nanocomposite system is a promising platform for treating superbug‐infected wounds.