Preparation of Film Based on Polyvinyl Alcohol Modified by Alkaline Starch and Lignin Fiber

This study presents an easily prepared film based on alkaline starch-polyvinyl alcohol hybrid and lignin fiber as an additive(SPL film).The SPL film was prepared under acidic conditions through a polycondensation reaction of PVA and a mixture incorporating alkaline starch and lignin fiber from agriculture or forest source.The examination using scanning electron microscopy(SEM)showed that the surface of SPL film was smooth and the lignin fiber had good compatibility within the film hybrid.Electrospray ionization mass spectroscopy(ESI-MS)and fourier transform infrared(FTIR)investigations indicated that alkaline starch and lignin fiber reacted with PVA under acidic conditions and that–CH_(2)–O–groups were involved in the cross-linking of the SPL system.In addition,the SPL film exhibited only 4%light transmittance,which effectively reduces the ultraviolet and visible light(UV-Vis)penetration,along with good performance when exposed to thermal degradation,in which the mass loss reached around 60%at 400℃.More-over,the SPL film acquired excellent tensile strength,which is much higher than that of PVA-lignin(PL)composite film.

A Fiber Optic Sensor for 2,4-dichlorophenol Analysis based on Optical Composite Oxygen-sensitive Film

A novel fiber optic sensor based on optical composite oxygen-sensitive film was developed for determination of 2,4-dichlorophenol(DCP).The optical composite oxygen-sensitive film consists of tris(2,2’-bipyridyl)dichloro ruthenium(II)hexahydrate(Ru(bpy)3Cl2)as the fluorescence indicator and iron(III)tetrasulfophthalocyanine(Fe(III)PcTs)as bionic enzyme.A lock-in amplifier was used for detecting the lifetime of the composite oxygen-sensitive film by measuring the phase delay of the sensor head.The different variables affecting the sensor performance were evaluated and optimized.Under the optimal conditions(i e,pH 6.0,25℃,Fe(III)PcTs concentration of 5.0×10^-5 mol/L),the linear detection range,detection limit and response time of the fiber optic sensor are 3.0×10^-7-9.0×10^-5 mol/L,4.8×10^-8 mol/L(S/N=3),and 220 s,respectively.The sensor displays high selectivity,good repeatability and stability,which have good potentials in analyzing DCP concentration in practical water samples.

The effect of fiber orientation on fracture response of metallic fiber-reinforced adhesive thin films

Incorporation of metallic fibers into the adhesive layer can significantly improve the mechanical behavior of the adhesive joint. This paper aims to assess the fracture behavior of an epoxy adhesive reinforced by longitudinal and lateral metallic fibers. Double cantilever beam(DCB) specimens were used to obtain the fracture energy of both non-reinforced and reinforced adhesives under mode I loading condition. In addition to the fiber orientation, the distance between the metal fibers was considered as the second key parameter in the experiments. It was concluded that although incorporation of metallic fibers in the adhesive layer improves the fracture behavior of neat adhesive, however, higher improvements were observed for the adhesive reinforced with longitudinal fibers. Furthermore, reducing the fiber distances resulted in higher values of fracture energy.

Low Temperature Coating of Anatase Thin Films on Silica Glass Fibers by Liquid Phase Deposition

Uniform crystalline TiO2 thin films were coated on silica glass fibers by liquid phase deposition from aqueous solution of ammonium hexafluorotitanate at low temperature. TiO2 thin films and nanopowders were prepared by adding H3BO3 into （NH4）2TiF6 solution supersaturated with anatase nano-crystalline TiO2 at 40 ℃. The effects of the deposition conditions on the surface morphology, section morphology, thickness of the deposited TiO2 thin films were investigated. The results indicate that the growth rate and particle size of the thin films were controlled by both the deposition conditions and the amount of anatase nano-crystalline TiO2.

The Effect of the Process on Mechanical Properties of Polylactic Acid-Date Palm Leaf Fibers Composite Films Produced By Extrusion Blowing

Biocomposite films prepared with melt compounding and film blowing have become a new trend in plastic research to deliver more eco-friendly packages.Polylactic acid(PLA)was melt compounded with minimally processed date palm leaf fiber(DPLF)and converted into films by blown film extrusion.The compounding was done in order to enhance the film mechanical properties in one hand,and to decrease the film production cost in the other hand.In this present study,a reference PLA film and films with 1%,2%,and 5%of DPLF(weight%)were produced with different process parameters.The spatial variations in films thickness and lay flat width indicate that the addition of DPLF up to 2%enhances the bubble stability for the tested process parameters.However,the composite with 5%DPLF shows nearly the same processability window as the neat PLA.The structural and mechanical characterizations of films suggest a reinforcing effect of the PLA matrix up to 2%of fiber(with an optimum at 1%).Larger DPLF loading leads to depressed and more anisotropic mechanical properties,related to an increased density of defects at the fiber-PLA fragile interface and to a DPLF-induced enhanced PLA thermal degradation and amorphous phase orientation.

CO2/CH4 separation using inside coated thin film composite hollow fiber membranes prepared by interfacial polymerization

Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.

Biological Tissue-Inspired Ultrasoft,Ultrathin,and Mechanically Enhanced Microfiber Composite Hydrogel for Flexible Bioelectronics

Hydrogels offer tissue-like softness,stretchability,fracture toughness,ionic conductivity,and compatibility with biological tissues,which make them promising candidates for fabricating flexible bioelectronics.A soft hydrogel film offers an ideal interface to directly bridge thin-film electronics with the soft tissues.However,it remains difficult to fabricate a soft hydrogel film with an ultrathin configuration and excellent mechanical strength.Here we report a biological tissue-inspired ultrasoft microfiber composite ultrathin(<5μm)hydrogel film,which is currently the thinnest hydrogel film as far as we know.The embedded microfibers endow the composite hydrogel with prominent mechanical strength(tensile stress~6 MPa)and anti-tearing property.Moreover,our microfiber composite hydrogel offers the capability of tunable mechanical properties in a broad range,allowing for matching the modulus of most biological tissues and organs.The incorporation of glycerol and salt ions imparts the microfiber composite hydrogel with high ionic conductivity and prominent anti-dehydration behavior.Such microfiber composite hydrogels are promising for constructing attaching-type flexible bioelectronics to monitor biosignals.

Interposition fixing structure of TiO_2 film deposited on activated carbon fibers

The immobilized photocatalyst, TiO2 film supported on activated carbon fibers (TiO2/ACFs) prepared with molecular adsorption-deposition (MAD), exhibits high stability in cyclic photodegradation runs. The interposition fixing structure between TiO2 film and carbon fiber was investigated by means of SEM-EDX, XRD, XPS and FTIR, and a model was proposed to explain this structure. With SEM examination of carbon fiber surface after removing the deposited TiO2 film, a residual TiO2 super-thin film was found to exist still. By determining surface groups on ACFs, titanium sulfate (Ti2(SO4)3) in burnt remainders of the TiO2/ACFs was thought to be formed with an interfacial reaction between TiO2 film and carbon fibers. These provide some evidence of firm attachment of TiO2 film to carbon fiber surface. In the consideration of characteristics of the MAD, the deposition mechanism of TiO2 film on ACFs was proposed, and the interposition fixing structure was inferred to intercrossedly form between TiO2 film and ACFs’ surface. This structure leaded to firm attachment and high stability of the TiO2 film.

ZnO micro-nano composite hydrophobic film prepared by the three-step method

The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the so,gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flowerlike structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.

Observation of 550 MHz passively harmonic mode-locked pulses at L-band in an Er-doped fiber laser using carbon nanotubes film

We demonstrate a passively harmonic mode-locked（PHML） fiber laser operating at the L-band using carbon nanotubes polyvinyl alcohol（CNTs-PVA） film. Under suitable pump power and an appropriate setting of the polarization controller（PC）, the 54^（th） harmonic pulses at the L-band are generated with the side mode suppression ratio（SMSR） better than 44 dB and a repetition frequency of 503.37 MHz. Further increasing the pump power leads to a higher frequency of 550 MHz with compromised stability of 38.5 dB SMSR. To the best of our knowledge, this is the first demonstration on the generation of L-band PHML pulses from an Er-doped fiber laser based on CNTs.

全降解植物纤维地膜在农业环境领域的研究动态

地膜在我国农业生产中发挥着重要作用,能够促进作物的生长发育,提高农业生产力。然而随着地膜的广泛应用,其造成的环境问题日益严重。近年来,伴随着可降解材料的不断开发与膜材料加工工艺的不断更新,为全降解植物纤维地膜的发展提供了契机。本文就纤维地膜出现的背景、现状、面临的问题及未来的发展趋势进行了分析与探讨。随着制备工艺的不断改进和人们对于环境问题的愈渐关注,植物纤维地膜将成为未来农业新材料发展的重要领域。

可降解地膜对大棚内土壤温湿度和草莓产量及品质的影响初探

冬季大棚草莓种植常用地膜覆盖,塑料残膜危害严重,试验以塑料地膜为对照,研究两种PBAT地膜(PBAT地膜1、PBAT地膜2)和一种环保型麻地膜对大棚内土壤温湿度和草莓产量及品质的影响,验证可降解地膜在草莓种植中应用的可行性。结果表明:PBAT地膜1草莓苗穴处温湿度较高,麻地膜膜下湿度最低;可降解地膜早期开花率和结果率高于塑料地膜;PBAT地膜1和麻地膜栽培的草莓早期产量显著高于塑料地膜,分别高出33.37%和22.98%,草莓总产量各处理间无显著差异;结果盛期各处理的草莓甜度和硬度无显著差异,塑料地膜、PBAT地膜1和麻地膜草莓单果重更高。试验初步表明,PBAT地膜和麻地膜可以用于冬季大棚草莓种植,其中PBAT地膜1和麻地膜效果最优。

可溶固着软质磨粒抛光薄膜制备及性能研究

目的实现微小光学器件高效、高质量、绿色的可溶固着软质磨粒薄膜抛光,对可溶固着软质磨粒抛光薄膜的制备工艺及抛光性能进行研究。方法研究可溶树脂、不可溶树脂、磨粒和薄膜基底等原料对成膜及抛光性能的影响,探索可溶固着软质磨粒抛光薄膜制备工艺,以光纤连接器作为加工对象验证抛光薄膜的抛光特性。结果选用双峰SiO_(2)作为磨粒,采用环氧树脂(质量分数为95%)和聚丙烯酸树脂(质量分数为5%)组成的“可溶”混合树脂为结合剂,可实现磨粒层逐步溶解。在磨粒涂覆层中添加5%(质量分数)的硅橡胶可调节磨粒涂覆层成膜后的弹性模量和硬度,使薄膜兼顾抛光性能和耐用性。对PET薄膜基底进行电晕处理可增强其表面附着力。选用含1%(质量分数为)有机硅烷偶联剂的聚氨酯树脂作为PET基底和磨粒涂覆层连接剂,结合强度好,成膜后表面无裂纹。通过光纤端面抛光对比实验发现,可溶固着软质磨粒抛光薄膜的抛光性能和耐用性均优于日本NTTAT抛光片的相关性能。可溶固着软质磨粒抛光薄膜使用25次后,光纤端面仍可保持表面光滑,曲面面形完整,表面粗糙度Ra小于5 nm,回波损耗大于45 dB,连接损耗小于0.1 dB。结论抛光实验表明,可溶固着软质磨粒抛光薄膜能实现光纤端面的高效精密加工。

两种麻纤维育秧膜对水稻秧苗根际土壤微生物群落结构的影响

试验主要探究了壳寡糖麻育秧膜和普通麻育秧膜对水稻秧苗根际土壤理化性质和微生物群落结构的影响。结果表明:使用两种不同麻育秧膜组中土壤pH、总氮含量增加;普通麻育秧膜处理下土壤有机质显著降低;壳寡糖麻育秧膜处理下总钾含量显著降低。与无膜覆盖的对照组相比,两种不同麻育秧膜处理下水稻秧苗根际土壤真菌多样性并没有显著变化,而细菌的多样性和丰富度显著降低。对根际土壤理化性质和土壤微生物群落进行冗余分析,发现水解氮与根际土壤真菌群落的相关性最大,而土壤有机质则与根际土壤细菌群落分布的相关性最大。

界面聚合法制备低压中空纤维纳滤复合膜

现有中空纤维纳滤膜在实际应用中能耗较高.采用干湿法纺丝技术制备聚砜(PSf)中空纤维超滤膜作为基膜,分别选用哌嗪(PIP)和均苯三甲酰氯(TMC)为水相单体和有机相单体,通过界面聚合工艺的优化,成功制备了低压中空纤维纳滤膜.用扫描电子显微镜和原子力显微镜对膜表面形貌进行表征,用傅里叶变换红外光谱仪和X射线光电子能谱仪分析膜表面的化学结构和元素组成,测试了复合膜的表面水接触角、Zeta电位、截留分子量和孔径分布,研究了单体浓度、界面聚合反应时间以及测试压力对复合膜性能的影响并确定了最佳的工艺条件.结果表明,优化的低压中空纤维纳滤膜具有低交联度的聚酰胺功能层,在0.2 MPa的测试压力下,纯水通量达到(16.0±0.4)L/(m^(2)·h),对质量浓度为1 g/L的盐溶液的截留率为Na_(2)SO_(4)(94.2%±0.9%)>MgSO_(4)(92.2%±0.9%)>MgCl_(2)(51.0%±0.5%)>NaCl(9.5%±0.3%),表现出优异的Na_(2)SO_(4)/NaCl选择性.

豆渣可溶性膳食纤维的提取及其制备可食用膜的研究

豆渣是大豆加工的大宗副产物,富含膳食纤维。采用微波辅助酶解水提法提取豆渣可溶性膳食纤维(SDF),然后将其制成可食用膜。通过单因素试验和正交试验优化后的提取工艺参数为水料比25∶1(mL/g)、纤维素酶添加量3%、水解时间2 h,此条件下豆渣SDF提取率为18.65%。然后通过正交试验优化了用豆渣SDF制备可食用膜的配方为SDF 1.0 g、甘油4.5 g、CMC 1.0 g、海藻酸钠1.5 g。用最优配方制备的可食用膜具有良好的性能:膜厚度0.032 mm、透明度13.26%、溶解速度25 s/g、水蒸气透过系数0.61 g·mm/m^(2)·d·kPa、透油系数4.15 g·mm/m^(2)·d。该研究可为豆渣的深加工提供方法参考,所制备的可食用膜有望用于食品加工、包装行业。

PVDF/6H-SiC composite fiber films with enhanced piezoelectric performance by interfacial engineering for diversified applications

Piezoelectric silicon carbide(SiC)has been quite attractive due to its superior chemical and physical properties as well as wide potential applications.However,the inherent brittleness and unsatisfactory piezoelectric response of piezoelectric semiconductors remain the major obstacles to their diversified applications.Here,flexible multifunctional PVDF/6H-SiC composite fiber films are fabricated and utilized to assemble both piezoelectric nanogenerators(PENGs)and stress/temperature/light sensors.The open cir-cuit voltage(V_(oc))and the density of short circuit current(I_(sc))of the PENG based on the PVDF/5 wt%6H-SiC composite fiber films reach 28.94 V and 0.24μA cm^(-2),showing a significant improvement of 240%and 300%compared with that based on the pure PVDF films.The effect of 6H-SiC nanoparticles(NPs)on inducing interfacial polarization and stress concentration in composite fiber films is proved by first-principles calculation and finite element analysis.The stress/temperature/light sensors based on the composite fiber film also show high sensitivity to the corresponding stimuli.This study shows that the PVDF/6H-SiC composite fiber film is a promising candidate for assembling high-performance energy harvesters and diverse sensors.

捻度对渔用UHMWPE裂膜纤维线股拉伸性能与耐磨性能的影响研究

为促进超高分子量聚乙烯裂膜纤维(简称UHMWPE裂膜纤维)在渔用绳网中的应用,以膜裂法制备渔用UHMWPE裂膜纤维为原料,通过加捻制备渔用UHMWPE裂膜纤维线股,在此基础上,考察了加捻对UHMWPE裂膜线股的线密度、直径、拉伸性能和耐磨性能的影响。结果显示:UHMWPE裂膜纤维线股随捻度的增加表现出直径逐渐减小、实际线密度先增大后减小以及捻回角逐渐增加等特征;对于不同线密度规格的UHMWPE裂膜纤维线股,随着捻度的增加,其断裂强力均呈现降低的趋势,且纤维线密度越低,加捻对线股断裂强度的影响越小;1600 D的UHMWPE裂膜纤维线股的磨损次数随捻度的增加而降低,而3200和4800 D线股的磨损次数随捻度的增加呈现先降低后升高的变化趋势,且4800 D的不同捻度的线股之间的磨损次数无显著性差异(P<0.05),显示出纤维线密度越大,加捻对其耐磨性能的影响越小。1600、3200和4800 D的UHMWPE裂膜纤维线股的结节强力随捻度的增大呈现先升高后降低的变化趋势,当预加捻度为120 T·m^(-1)时,3种线密度线股的结节强力达到最大值,分别为204.15、373.5、562.41 N,较未加捻UHMWPE裂膜纤维分别提高了50.14%、37.13%和30.22%。在本实验捻度设置范围内,1600 D裂膜线股的结节强度随捻度的增加而增大,较未加捻裂膜纤维结节强度提高了32.49%。研究表明,无捻或低捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维无结网的制备;无捻或低捻度的高线密度UHMWPE裂膜纤维线股则具有较好的耐磨性能;中高捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维有结网的制备。研究结果可为渔用UHMWPE裂膜纤维绳网材料的加工、开发与应用提供参考。

玄武岩纤维浸润剂研究综述

玄武岩纤维浸润剂可有效提高玄武岩纤维的黏结强度、拉伸强度等性能,在玄武岩纤维成型及纤维复合材料生产过程中均具有重要作用。介绍了增强型浸润剂、纺织型浸润剂和增强纺织型浸润剂的材料性能、化学组成及应用效果,分析了各种浸润剂的优缺点,总结了浸润剂应用现状,展望了玄武岩纤维浸润剂的发展方向。