再生纤维素/聚乙烯醇/壳聚糖/二氧化钛抗菌复合膜的制备及性能

以微晶纤维素(MCC)和聚乙烯醇(PVA)为原料,1-丁基-3-甲基咪唑氯盐([Bmim]Cl)为溶剂,通过MCC溶解再生与PVA共混制备再生纤维素(RGC)/PVA基膜,并利用壳聚糖(CS)和纳米二氧化钛(TiO₂)共混液包覆方法制备RGC/PVA/CS/TiO₂抗菌复合膜。通过FT-IR、XRD和SEM对复合膜的形貌和结构进行表征,并对复合膜的热学、力学、光学、阻隔和抑菌等性能进行测试分析。研究结果表明：壳聚糖和二氧化钛成功复合于纤维素基膜,RGC/PVA/CS/TiO₂复合膜的热分解主要由CS-TiO₂包覆层和RGC/PVA基膜的分解构成。与再生纤维素(RGC)膜相比,当TiO₂质量分数为0.2%时,RGC/PVA/CS/TiO₂复合膜的拉伸强度提升了39.28%,断裂伸长率提升了51.66%,透光率保持在88.72%,氧气透过率下降了47.77%,且对大肠杆菌、金黄色葡萄球菌和枯草杆菌具有良好的抑制作用。     

鱼鳞明胶/壳聚糖/薰衣草精油抗菌复合膜制备及性能

以鱼鳞明胶(SG)和壳聚糖(CS)为原料,薰衣草精油(LEO)为抗菌剂,通过共混法制备抗菌复合膜,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,LEO与SG/CS基膜较好复合,与SG/CS基膜相比,当LEO添加量为1%时,复合膜具有良好的力学强度(26.36 MPa),断裂伸长率提升了12.96%；透明度有所下降,透光率为70.50%；耐水性能和水蒸气阻隔性能显著增强,含水率、水溶性和水蒸汽透过率分别下降了22.48%、30.49%和26.03%；DPPH自由基清除率提高了247.88%,抗氧化性显著提高；同时对大肠杆菌和金黄色葡萄球菌具有良好的抑菌作用。     

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。     

细菌纤维素/碳纳米管/MnO2复合超级电容器电极

基于细菌纤维素(BC)的三维多孔及柔性支架结构和碳纳米管(MWCNT)的优良导电性,构筑起BC/MWCNT自支撑导电基底。其中,二者通过氢键紧密结合,协同赋予复合基底优良的电导率和机械性能。然后将二氧化锰(MnO₂)电沉积在该基底上,构建了一种新型的BC/MWCNT/MnO₂薄膜电极。BC/MWCNT复合膜的多孔结构、电解质吸收特性及蜂窝状活性MnO₂纳米片的桥连结构,赋予其出色的电化学性能(在1 mA cm_-2^{的电流密度下},其面积比电容和质量比电容分别达到1.17 F cm_-2^和200 F g_-1⁾和显著的循环稳定性(在20 mA cm_-2^{的电流密度下进行}10000次循环后,其比电容保留率稳定在96%)。这种无粘合剂的薄膜电极制备简便且成本低廉,在开发柔性储能器件方面具有巨大潜力。关键词：细菌纤维素(BC)；碳纳米管(MWCNT)；二氧化锰(MnO₂)；膜电极；电化学性能中图分类号：TQ630 文献标识码： A 文章编号：1003-5214 (2020) 01-0000-00     

Cu2O/rGO复合材料修饰阴极强化MFC产电脱氮性能及其机理

微生物燃料电池(MFC)在处理含硝酸盐(NO_3^--N)废水时具有同时产电和脱氮的潜力,寻找成本低且改善其产电脱氮性能的阴极修饰材料是MFC在含氮废水处理领域应用的关键。氧化亚铜/还原氧化石墨烯(Cu₂O/rGO)复合材料具有良好的电化学性能,在替代铂基材料提高MFC性能方面具有一定的应用前景。本研究通过还原法制备了Cu₂O/rGO复合材料,并对材料的结构和氧还原性能进行表征；同时,将其负载于阴极碳布后分析其电化学性能,并通过MFC的输出电压、功率密度和NO_3^--N的去除率探究Cu₂O/rGO阴极对MFC产电和脱氮性能的强化作用；通过对反硝化相关酶活性和胞外聚合物的测定,探究Cu₂O/rGO阴极强化MFC性能的机理。结果表明：Cu₂O/rGO复合材料具有大量的介孔结构,能够为电子传递提供更多的通道,并且Cu₂O/rGO复合材料具有良好的氧化还原可逆性；与Pt/C阴极相比,Cu₂O/rGO阴极的交换电流密度升高33.53%,电子转移阻力降低65.53%；Cu₂O/rGO-MFC在处理NO_3^-N废水时获得的最大平均输出电压(662.54 mV)、最大功率密度(26.27 mW/cm^₂)、平均库伦效率(32.02%)和NO_3^--N去除速率(83.33 mg NO_3^--N L/h)均高于Pt/C-MFC(485.33 mV,16.98 mW/cm^₂,7.38%,41.67 mg NO_3^--N L/h)；Cu₂O/rGO复合材料通过提高MFC阴极反硝化关键酶活性和类蛋白组分含量,改善了MFC的产电和脱氮性能。     

新型PVC/OHA/D2EHPA基膜增强型聚合物包容膜的制备及性能评价

为解决聚合物包容膜(PIM)传输效率低的问题。制备了一种以聚氯乙烯(PVC)为基体,包含固液两种载体的基膜增强型PIM。以N-羟基正辛酰胺(OHA)作为新型载体固定于基膜孔道内,利用其与有机萃取剂二(2-乙基己基)磷酸酯(D2EHPA)的协同作用,实现高效传质。对制备的基膜增强型PIM进行SEM、EDS、FTIR、XPS、力学性能以及传质性能考察与表征。结果表明,载体配比为22% OHA+17% D2EHPA的基膜增强性PIM对50 mg/L的Zn_²⁺的10h回收效果最佳,萃取率和反萃率分别为59.86%和51.10%。5个周期的运行实验中,基膜增强型PIM初始传质通量为587.36 mg.m_^-2.h_^-1,约是仅包含液相萃取剂PIM传质通量(312.64 mg.m_^-2.h_^-1)的2倍。5个循环周期结束后,基膜增强型PIM传质通量仍高于仅包含液相萃取剂PIM传质通量。     

PIN/PAN聚合物基电解质膜的制备及性能

利用静电纺丝技术制备了聚吲哚/聚丙烯腈(PIN/PAN)聚合物基电解质膜,代替纸基铝空气电池中的纤维素纸(C-P),并应用于固态铝空气电池。探究了PIN含量对电解质膜离子电导率及吸液率的影响。采用SEM和FTIR对PIN/PAN聚合物基电解质膜表面形貌及化学组成进行分析。借助电化学工作站和电池测试系统,分析了电解质膜离子电导率及固态铝空气电池放电特性。结果表明,采用PIN/PAN聚合物基电解质膜可有效提升固态铝空气电池性能,在3 mA.cm_^-2、5 mA.cm_^-2、7 mA.cm_^-2电流密度下,放电时长比纸基铝空气电池分别提升了21%、27%、34%,且放电时长与电解质膜的吸液率及离子电导率相关。其中4%PIN/PAN聚合物基电解质膜离子电导率可达6.7×10_^-4 S.cm_^-1,同时对碱性溶液具有良好的吸附能力,吸液率最高可达496%,为纤维素纸的3.2倍。     

295/60R22.5低断面全钢载重子午线轮胎的设计

介绍295/60R22.5低断面全钢载重子午线轮胎的设计。结构设计：外直径　922 mm,断面宽　294 mm,行驶面宽度　246 mm,行驶面弧度高　9.5 mm,胎圈着合宽度　248 mm,胎圈着合直径　569.5 mm,断面水平轴位置H₁/H₂　0.915 5,采用4条纵向花纹沟设计。施工设计：采用双复合挤出胎面,1^#带束层采用4＋3×0.33ST钢丝帘线,2^#和3^#带束层采用3＋8×0.33HT钢丝帘线,4^#带束层采用5×0.30HI钢丝帘线,胎体采用3×0.24＋9×0.225CCST钢丝帘线,采用一次法成型机成型、热板硫化机硫化。成品性能试验结果表明,轮胎的充气外缘尺寸、强度性能、耐久性能和高速性能均符合国家标准和设计要求。     

一例铟基MOF的合成、结构及其甲烷存储

研究旨在合成一种新型铟基有机骨架材料,用于甲烷存储,以应用于清洁能源领域。研究使用In(NO₃)₃.4H₂O和H₃BTB,醋酸作模板剂,采用溶剂热法来实现材料的合成,所得材料表现出较高的比表面积2487 m₂ ^g_-1^,和永久孔隙结构,孔体积为1.07 cm₃ ^g_-¹。在273 K、80 bar条件下,甲烷重量工作能力达到397 cm₃ ^g_-1⁽0.29 g g_-1⁾。这些结果表明了该材料在甲烷存储方面的潜在应用。值得注意的是,本研究的创新之处在于成功合成具有优异甲烷吸附性能的铟基MOF材料,为高性能气体吸附材料的开发提供了新方向。因此,本文为清洁能源技术的发展提供了新的思路。此外,该材料还表现出良好的可重复性,为其在实际应用中的长期可持续性提供了有力支持。     

235/75R17.5低滚动阻力子午线轮胎的设计优化

介绍235/75R17.5低滚动阻力子午线轮胎的设计优化。结构设计参数不变,即外直径　794 mm,断面宽　236 mm,行驶面宽度　188 mm,行驶面弧度高　6 mm,胎圈着合直径　443.5 mm,胎圈着合宽度　184 mm,断面水平轴位置（H/₁/H/₂）　1.002 86。采取优化措施为：采用低滚动阻力胎面胶和胎侧胶配方,胎面采用胎冠胶＋小翼胶复合形式挤出,胎体采用3×0.24/9×0.225CCST钢丝帘线替代3＋9×0.22＋0.15NT钢丝帘线,带束层采用2＋7×0.30ST钢丝帘线替代4＋3×0.33ST和3＋9＋15×0.22＋0.15NT钢丝帘线,优化胎圈部位材料分布,采用低温硫化工艺。成品性能试验结果表明,优化轮胎的耐久性能提高,高速性能达到企业标准要求,滚动阻力系数为6.12 N·kN^-1 ,满足市场要求。     

High oxygen barrier property of polyethylene composite films with bilayer polyvinyl alcohol coating for emergency foods in high-humidity environments

The limited oxygen barrier of polyethylene (PE) films has restricted their further application in food packaging, like emergency foods. Although its oxygen barrier property can be improved by applying a polyvinyl alcohol (PVA) coating, the application of PVA/PE composite films in high-humidity environments is still challenging. Hence, this study aimed to enhance the oxygen barrier properties of PVA/PE composite films in high-humidity environments. Specifically, PVA coatings were modified by the itaconic acid (IA) and magnesium-aluminum layered double hydroxides (LDH), and then applied to PE films as bilayer coating. Because of the unique bilayer coating on the PE surface, the oxygen barrier property of PVA/PE composite film (IA/LDH-p) in high-humidity environments has been further improved. The results confirmed that IA/LDH-p had an oxygen permeability coefficient of 1.92 ± 0.16 × 10⁻¹⁶ cm³ cm/(cm² s Pa) under a high-humidity environment test, 82.42% better than that of single-layer coating coated on PE surface. After being stored at RH 90% for 36 h, the tensile strength and elongation at break values of IA/LDH-p were 27.20 MPa and 919.63%, respectively. Overall, this obtained PVA/PE composite films showed great potential for application in emergency foods packaging, particularly in high-humidity environments.     

Effect of copper sulfate pentahydrate on the structure and properties of poly(vinyl alcohol)/graphene oxide composite films

Poly(vinyl alcohol) (PVA)/graphene oxide (GO)/copper sulfate pentahydrate (CuSO₄·5H₂O) composite films were prepared by the solution casting method, and the effect of CuSO₄·5H₂O on the structure and properties of the PVA/GO composites was investigated. Fourier transform infrared (FTIR) analysis proved the crosslinking interaction between CuSO₄·5H₂O and the ? OH group of PVA. The crystallinity of the composite films increased first and then decreased. For the composite films, the tensile strength, Young's modulus, and yield stress values improved with increasing CuSO₄·5H₂O, whereas the elongation at break decreased compared with that of the neat PVA/GO composite film. The thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) patterns of the PVA/GO/CuSO₄·5H₂O composite films showed that the thermal stability decreased; this was consistent with the TGA–FTIR analysis. A remarkable improvement in the oxygen‐barrier properties was achieved. The oxygen permeability coefficient was reduced by 60% compared to that of the neat PVA/GO composite film. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44135.     

Fabrication and characteristics of graphene oxide/nanocellulose fiber/poly(vinyl alcohol) film

Poly(vinyl alcohol) (PVA), PVA/nanocellulose fiber (CNF), and PVA/CNF/graphene oxide (GO) films were prepared simply by casting stable aqueous mixed solutions. FTIR investigation indicated that hydrogen bonding existed between the interface of GO and PVA‐CNF. Scanning electron microscopy and X‐ray diffraction analysis showed that GO was uniformly dispersed in PVA‐CNF matrix. Introducing CNF into PVA caused a significant improvement in tensile strength, and further incorporating GO into PVA/CNF matrix led to a further increase. The tensile strength of the neat PVA film, PVA/CNF composite, and PVA/CNF/GO film (0.6 wt % GO) was 43, 69, and 80 MPa, respectively. Moreover, when incorporating 8 wt % CNF into PVA matrix, O₂ permeability and water absorption decreased from 13.36 to 11.66 cm³/m²/day and from 164.2% to 98.8%, respectively. Further adding 0.6 wt % GO into PVA/CNF matrix resulted in a further decrease of permeability and water absorption to 3.19 cm³/m²/day and 91.2%, respectively. Furthermore, for all composite samples, the transmittance of visible light was higher than 67% at 800 nm. CNF and GO‐reinforced PVA with high mechanical and barrier properties are potential candidates for packaging industry. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45345.     

Preparation,mechanical and ablation properties of a C/C-TaB2-SiC composite

A C/C-TaB₂-SiC composite was successfully prepared by high-solid-loading slurry impregnation combined with polymer infiltration and pyrolysis. The composite had a density of 3.46 g/cm³ and consisted of pyrolyzed carbon, carbon fibers, TaB₂ particles, and precursor-derived SiC with their mass fractions of 7.8 %, 13.0 %, 58.6 %, and 20.6 %, respectively. The C/C-TaB₂-SiC composite possessed a flexural strength of 248.2 ± 16.8 MPa and a fracture toughness of 13.7 ± 1.6 MPa·m^1/2, and demonstrated a non-brittle fracture behavior. After exposure to oxyacetylene flame with a heat flux of 4.18 MW/m² for 120 s, the ablation temperature of the sample surface reached a maximum of 2263 °C, and the mass and line ablation rates were 2.24 mg/s and 12.92 µm/s, respectively. The ablation resistance mainly comes from the hindrance of oxygen diffusion by the oxide layer composed of tantalum oxide and a small amount of SiO₂.     

Enhancing polymer/graphene oxide gas barrier film properties by introducing new crystals

A transparent, gas barrier film comprised of poly(vinyl alcohol) (PVA) and graphene oxide (GO) is synthesized through combined methods of solution blending and isothermal recrystallization. The recrystallized PVA/GO film with only 0.07 vol% GO gives an O₂ transmission rate <0.005 cc m⁻² day⁻¹ and an O₂ permeability <5.0 × 10⁻²⁰ cm³ cm cm⁻² Pa⁻¹ s⁻¹; hence, it is far superior to other blend polymer/inorganic composites. The excellent O₂ barrier properties are attributed to a unique hybrid of PVA crystals and GO sheets. PVA crystals form around the GO during isothermal recrystallization, indicating that a GO sheet can act as a nucleating agent. The newly formed PVA crystals fill in the spaces between the GO sheets, and together they become ultra-large impermeable regions, which can prevent the passage of O₂. The hybrid film has potential applications in flexible electronics, pharmaceuticals, and food packaging.     

Multifunctional and pH-responsive dialdehyde cellulose/polyvinyl alcohol composite film reinforced with curcumin

The rational design of food packaging films with good antimicrobial activity, antioxidant activity, and monitorability is of great importance in intelligent packaging. In this study, an active composite film was prepared by adding curcumin to a dialdehyde cellulose (DAC)/polyvinyl alcohol (PVA) matrix. It was found that the Cur/DAC/PVA composite film exhibited optimal tensile strength at 30°C. The tensile strength of the composite film control PVA/DAC film was observed to increase by 176% due to the affection of hydrogen bonding. Under the influence of curcumin, the UV barrier property and antioxidant activity of the composite film were significantly increased, and the ABTS⁺• was removed by 0.5Cur/DAC/PVA up to 88% at low curcumin content. The water solubility and water vapor permeability were both reduced to some degree. It was also observed that composite film displayed an inhibitory effect on the growth of Staphylococcus aureus bacteria. Meanwhile, the Ritger and Peppas release model was used to study the release control capability of curcumin. Furthermore, the Cur/DAC/PVA composite film demonstrated excellent color response to pH, which it they could be used for intelligent packaging with real-time visual monitoring.     

Development and compatibility assessment of new composite film based on sugar beet pulp and polyvinyl alcohol intended for packaging applications

In this study, interaction and compatibility between sugar‐beet pulp (SBP) and polyvinyl alcohol (PVA) in blend films was assessed. Film‐forming dispersions of different ratios of SBP to PVA (100/0, 75/25, 50/50, and 25/75) were cast at room temperature. The effects of adding PVA to SBP on the resulting film's physical, mechanical and barrier properties and thermal stability were investigated. X‐ray diffraction and environmental scanning electron microscopy (ESEM) were used to characterize the structure and morphology of the composites. When PVA was also added to the composite films, the films became softer, less rigid and more stretchable than pure SBP films. The addition of PVA gave significantly greater elongation at break (12.45%) and lower water vapor permeability (1.55 × 10^?10 g s^?1 m^?1 Pa^?1), but tensile strength did not markedly change, remaining around 59.68 MPa. Thermogravimetric analysis also showed that SBP/PVA film had better thermal stability than SBP film. The ESEM results showed that the compatibility of SBP50/PVA50 was better than those of other composite films. These results suggest that when taking all the studied variables into account, composite films formulated with 50% PVA are most suitable for various packaging applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41354.     

Oxygen barrier properties of biaxially oriented polypropylene/polyvinyl alcohol blend films

The biaxially oriented PP/PVA blend film was prepared and had the higher oxygen barrier property by about 130 times than that of a biaxially oriented PP film. When the viscosity ratio (η_d(PVA)/η_m(PP)) decreased, the dispersed PVA phase was developed into platelets during stretching process. Oxygen permeability was dependent on the number and size of PVA platelet. However, the Oxygen permeability was not sensitively changed in above 25 wt% of PVA. To obtain excellent barrier property, the optimum amount of plasticizer and initiator was required. A pasticizer was related to the size and degree of crystallization of PVA platelet. An initiator played the role of a compatibilizer. The oxygen barrier was enhanced with increasing the viscosity of PP and draw ratio. The higher viscosity of PP was advantageous for preventing the delamination of a blend film, and the moisture vapor permeability was not affected with the laminar structure. As a result, the biaxially oriented PP/PVA blend film had the potential of substituting for the PVDC coated BOPP film.     

Preparation and properties of poly(urethane acrylate) (PUA) and tetrapod ZnO whisker (TZnO‐W) composite films

Tetrapod zinc oxide whiskers (TZnO‐Ws) were successfully synthesized via a thermal oxidation method and confirmed using Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy. A series of poly(urethane acrylate) (PUA)/TZnO‐W composite films with various TZnO‐W contents were prepared via a UV curing method and their physical properties were investigated to understand their possible use as packaging materials. The morphological, thermal, mechanical, antibacterial and barrier properties of the PUA/TZnO‐W composite films were interpreted as a function of TZnO‐W content. The thermal stability, barrier properties and antibacterial properties of the composite films, which were strongly dependent upon their chemical and morphological structure, were enhanced as the TZnO‐W content increased. The oxygen transmission rate and water vapor transmission rate decreased from 614 to 161 cm³ m^?2 per day and 28.70 to 28.16 g m^?2 per day, respectively. However, the mechanical strength of the films decreased due to the low interfacial interaction and poor dispersion with high TZnO‐W loading. The enhanced barrier properties and good antibacterial properties of the PUA/TZnO‐W composite films indicate that these materials are potentially suitable for many packaging applications. However, further studies are needed to increase the compatibility of polymer matrix and filler. © 2012 Society of Chemical Industry