Changes in Structure and Properties of Soybean Protein/Poly （vinyl alcohol） Blended Fibers Subjected to Wet Heat Treatment

The properties of soybean protein/poly（vinyl alcohol） （SP/ PVA） blended fibers subjected to wet heat treatment in hot water were measured. The structure of fibers was investigated by scanning electron microscope （SEM）, Fourier transform infrared （FTIR） spectroscopy, wide-angle X-ray diffraction （WXD） and differential scanning calorimetry （DSC）. The results show that the wet heat treatment above 100℃ has a great influence on the properties and structure of SP/PVA blended fibers. After the wet heat treatment at high temperature, the fibers exhibit the severe shrinking and yellowing, the great decrease in breaking strength and adhesive aggregation. The fibers show a broader main X-ray diffraction peak with the disappearance of minor diffraction peaks, a double DSC melting behavior with the peak temperatures of 215 and 233℃, and a weaker intensity of crystallization-sensitive absorbance peak of PVA component at 1 142 cm^-1. Therefore it is concluded that the wet heat treatment above 100℃ leads to a change in the crystalline structure of fibers and the scission and degradation of PVA macromolecular chains.     

Enhancement of Adhesive Strength of Ultrahigh Molecular Weight Polyethylene Fibers Prepared by Polar Polymer Implantation

A new technique was proposed to enhance the adhesive strength of ultrahigh molecular weight polyethylene （UHMWPE） fibers. Polar polymer was implanted into UHMWE gel fibers during extracting process and can then be trapped on the surface of the fibers after subsequent ultra-drawing. The physical and chemical changes in the fiber structure were examined with scanning electron microscopy （SEM） and Fourier transform infrared （FTIR） spectroscopy. The mechanical and interfacial adhesion properties of UHMWPE fibers were investigated with tensile testing. The results showed that there were polar groups on the smface of pretreated UHMWPE fiber. The interracial shear strength of UHMWPE fibers with epoxy resin was greatly improved without sacrificing the excellent mechanical p~perties of fibers. After pretreated with ethylene/vinyl acetate copolymer （EVA）, the shear strength of the interface between fiber and epoxy resin increased from 1.06 to 2.49 MPa, while the integrated mechanical properties d the pretreated UHMWPE fibers were still optimal.     

Dyeing Behavior of Yak Hair Fiber Treated with Microwave Low Temperature Plasma

The scales on the surface of yak hair fiber act as barriers during the dyeing process. In order to solve the scale problem and to improve the dyeability of yak hair, yak hair fiber was treated by microwave low temperature plasma （MLTP） in this study. The weight loss and the dyeing properties of the yak hair fiber modified by MLTP were investigated. Scanning Electron Microscopy （SEM） photographs were taken to observe the changes in the surface shape of yak hair fiber before and after treatment. Results showed that after MLTP treatment, the scale structure of yak hair was weakened and damaged greatly and the noticeable changes on the surface shape took place. At the same time, a significant improvement in dyeing properties of yak hair fiber was exhibited.     

Ordering and disordering of in situ grown MgAl-layered double hydroxide and its effect on the structural and corrosion resistance properties

A MgAl-layered double hydroxide(MgAl-LDH) protective film was developed on AA6082 substrates via the in situ hydrothermal growth method to obtain a distinct cauliflower-like LDH structure, and coated substrates were further heat-treated in air at temperatures from 100 to 250℃ to further improve the corrosion resistance of MgAl-LDH by taking advantage of the LDH memory effect; also, the effect of calcination on MgAl-LDH structural stability and the corresponding corrosion resistance properties were investigated. The structural characterization of uncalcined and calcined LDH films were examined using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The corresponding corrosion protection efficiency of the developed coating was studied through potentiodynamic polarization experiments and by electrochemical impedance spectroscopy. Compared with uncalcined MgAl-LDH, the calcined film showed a relatively lower corrosion current density and a higher impedance value, especially after heat treatment at 250℃. The findings demonstrate that calcination strongly affects the oriented growth of the LDH and causes an increase in the surface area and contraction of the basal spacing, which in turn caused a compact structure that substantially influenced the LDH corrosion resistance properties.     

Structures of Silk Fibers Grafted with Hexafluorobutyl Methacrylate

The relationship between the graft yield and the effect of hexafiuorobutyl methacrylate graft treatment on the structural changes of the silk fibers was studied on the basis of the results of scanning electron micrograph photographs （SEM）, infrared spectroscopy （IR）, Raman spectrum, wide-angle X-ray diffraction patterns （WAXD）, nuclear magnetic resonance（NMR） and amion acid analysis. The results showed that the crystalline regions of grafted fibers were hardly affected and the fiber fission occurred on the cross sections of grafted fibers. The surface of fibers was covered with a high polymer film. The Raman spectrum showed there was little change in the conformation of grafted fibers which mainly remained β-sheet conformation. The IR of the grafted silk fibers showed new absorption of bands occurred which belonged to the stretching-vibrationabsorption-peak bands of Vo-o and VC-F of aliphatic ester species. The CF3-, -CF2- and -CFH- grafted silk macromodecul were verified in the NMR spectrum. The amion acid analysis indicated fluoride monomers were inclined to graft with TYR, ARG and CLU silk fibers.     

Behavior of NiCrAlY coating on the TC6 titanium alloy

A NiCrAlY coating was deposited on the TC6 titanium substrate by arc ion plating (ALP). The structure and morphologies of the NiCrAlY coating were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the influence of vacuum heat treatment on the element diffusion behavior was studied. The results showed that the γ'-Ni₃Al phase was precipitated on the NiCrAlY coating after heat treatment. The Ni₃(AI,Ti), TiNi, and Ti₂Ni intermetallic layers appeared at the interface from the outside to the inside at 700℃, and the thickness of the intermetallic layers increased with the increase in temperature. At 700℃ Ti and Ni were the major diffusion elements, and the diffusion of Cr was observed when the heat treatment temperature increased up to 870℃. The violent inward diffusion of Ni at 950℃ resulted in the degradation of the NiCrAlY coating.     

Study on the behaviors of poly（p-phenylene benzobisoxazole） in coagulation

Poly（p-phenylene benzobisoxazole）（PBO） is a candidate of high performance materials for many applications. PBO materials＇ properties are considered to be closely related to their fabrication process, especially coagulation. In this paper, the coagulation effect on the chemical and microstructure of PBO was investigated with the help of a PBO model compound, 2, 2＇-（ 1,4-phenylene） bis （5-amino-6-benzoxazolole）. During coagulation, the hetero-cyclic ring of the PBO structure was experienced cleavage and even being broken down completely under some extreme conditions. Wide-angle X-ray diffraction （WAXD） analysis showed that different coagulants could cause the microstructure difference in PBO materials. In a slow coagulation process, PBO molecular chains aligned more orderly in the side-by-side direction （200）.     

Influence of deformation on precipitation in AZ80 magnesium alloy

Precipitates in the conventionally processed (solution treatment followed by aging) AZ80 alloy are coarse, cellular, and incoherent. They nucleate and grow on the basal planes of the matrix or distribute discontinuously in the alloy. Their unique morphology and undesired distribution make them ineffective for precipitation strengthening. This condition, however, can be modified by applying selected deformation and heat treatment conditions. The effect of deformation and heat treatment on the morphology and distribution of precipitates has been studied. Deformation was introduced by hot extrusion, cold rolling, or equal channel angular pressing (ECAP). The microstructures were characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that cold deformation improved precipitation more significantly than hot deformation, and twinning promoted precipitation more effectively than slip. When ECAP was applied, the Bc-route induced more precipitates than the A-route.     

Preparation and magnetic properties of CoFe2O4/TiO2 composite films

Using （Ti（OC4H9）4） and metal chlorates as starting materials, CoFe2O4/TiO2 composite films were prepared by sol-gel method. The effects of heat treatment temperature and pH of the precursor on microstructure and magnetic properties were studied. The phase structure of the samples was examined by X-ray diffraction. The microstructure was examined by scanning electron microscope, atomic force microscope and polarized microscope. The magnetic property was measured by vibrating sample magnetometer. The results show that the crystals of different phases grow up independently. CoFe2O4 is uniformly embedded into the TiO2 matrix in the prepared composite films, and the growth of composite films is dependent on the heat treatment temperatures and PH of the precursor. The average size of CoFe2O4 crystal is 19 nm in Nanocomposite film prepared when the heat treatment temperature is 800℃ and the pH of the precursor is between 2 and 3. The magnetism of the composite films is enhanced as the heat treatment temperature increases.     

Effect of austenitization heat treatment on the magnetic properties of Fe-40wt% Ni-2wt% Mn alloy

The effect of austenitization heat treatment on magnetic properties was examined by means of Mössbauer spectroscopy on an Fe-40wt%Ni-2wt%Mn alloy. The morphology of the alloy was obtained by using scanning electron microscopy (SEM) under different heat treatment conditions. The magnetic behavior of the non heat-treated alloy is ferromagnetic. A mixed magnetic structure including both paramagnetic and ferromagnetic states was obtained at 800℃ after 6 and 12 h heat treatments. In addition, the magnetic structure of the heat-treated alloy at 1150℃ for 12 h was ferromagnetic. With the volume fraction changing, the effective hyperfine field of the ferromagnetic austenite phase and isomery shift values were also determined by Mtssbauer spectroscopy.     

聚合交联型防皱整理剂整理工艺对织物的影响

本文通过对整理织物物理机械性能的测定及Ｘ光衍射图形、电镜照片的分析，探讨聚合交联型防皱整理剂Ｎ－羟甲基丙烯酸胺整理棉织物时轧烘焙与“湿固着”两种整理工艺对织物力学性能和微结构、形态结构的影响。     

聚亚苯基苯并二(口恶)唑的热分解行为

用热失重方法分析了聚亚苯基苯并二唑(PBO)纤维在不同气氛中的热分解行为,采用O zaw a法计算了PBO纤维在氮气和空气两种气氛中的热分解活化能。结果表明升温速率对PBO纤维的热分解温度有较大影响;氧气作为热分解反应的引发剂,大大降低了分解反应的活化能;由IR光谱对不同温度裂解产物结构的分析,推测了热氧化降解对PBO纤维分子结构的影响;在不同失重率时几乎相同的热分解活化能,表明无论热分解的气氛如何,PBO纤维的热分解均是一个无规引发的单阶段过程;结合PBO纤维在两种气氛中的热分解机理,解释了分解气氛对残碳率的影响。     

Adhesion of PBO Fiber in Epoxy Composites

The high mechanical and thermal performance of poly p-phenylene- 2, 6-benzobisoxazole ( PBO ) fiber provides great potential applications as reinforcement fibers for composites. A composite of PBO fiber and epoxy resin has excellent electrical insulation properties, therefore, it is considered to be the best choice for the reinforcement in high magnetic field coils for pulsed magnetic fields up to 100 T.However, poor adhesion between PBO fiber and matrix is found because of the chemically inactive and/or relatively smooth surface of the reinforcement fiber preventing efficient chemical bonding in the interface, which is a challenging issue to improve mechanical properties. Here, we report the surface modification of PBO fibers by ultraviolet (UV)irradiation, O2 and NH3 plasma, as well as acidic treatments. The interfacial adhesion strength values of all the treatments show the similar level as determined for aramid fibers by pull-out tests, a significant impact on fibermatrix-adhesion was not achieved. The surface free energy and roughness are increased for both sized and extracted fibers after plasma treatments together with maleic anhydride grafting. The sized fiber shows marginal improvement in adhesion strength and no change in fiber tensile strength because of the barrier effect of the finish.For the extracted fiber, different surface treatments either show no apparent effect or cause reduction in adhesion strength. Atomic force microscopy (AFM) topography analysis of the fracture surfaces proved adhesive failure at the fiber surface. The fiber surface roughness is increased and more surface flaws are induced, which could result in coarse interface structures when the treated fiber surface has no adequate wetting and functional groups. The adhesion failure is further confirmed by similar adhesion strength and compression shear strength values when the fiber was embedded in various epoxy resins with different temperature behavior. The tensile strength of fiber is sensitive to surface treatment conditions as revealed by a bimodal Weibull statistical distribution analysis. Considerable strength reduction occurred, particularly for cases of acidic and plasma treatments, while UV irradiation shows the better ability to retain fiber strength.     

再生竹纤维球形介孔气凝胶的表征

 为获得均一稳定的纤维素气凝胶,以再生竹纤维为原料,采用滴定悬浮和真空冷冻干燥的方法制备球形纤维素气凝胶。傅里叶变换红外光谱仪（FTIR）、X 射线衍射仪（XRD）、扫描电镜（SEM）分析结果表明,球形纤维素气凝胶为纤维素Ⅱ 型结构,内部为疏松多孔的网络状结构。球形纤维素气凝胶的比表面积均在240 m²/g 以上,且孔径均在15 nm 以下,最小密度可达37 mg/cm³,这表明球形纤维素气凝胶具有较高的比表面积、较小的孔径。热重分析（TG）结果表明,纤维素气凝胶大球的最大热失重温度为364.4℃,纤维素气凝胶中球的最大热失重温度为357.3℃,纤维素气凝胶小球的最大热失重温度为354.2℃,而再生竹纤维的最大热失重温度为354.0℃。球形纤维素气凝胶在污水处理、海水除油、重金属离子吸附等领域具有开发价值。     

PBO纤维表面二氧化钛涂层的构建及其抗紫外光性能研究

为提高聚对苯撑苯并二噁唑(PBO)纤维的抗紫外老化性能,以3-氨丙基三甲氧基硅烷(APTMS)为桥梁,在PBO纤维表面构建二氧化钛(TiO2)涂层,并考察了纤维改性前后的表面形貌、界面剪切强度(IFSS)、以及紫外光照射前后的力学性能等变化.研究结果表明,在PBO纤维表面构建二氧化钛涂层后,PBO纤维与树脂的界面剪切强...     

PAN基炭纤维高效催化石墨化研究

通过在磷酸和钼酸钠水溶液中交替直流电解,实现磷-钼元素催化剂在PAN基炭纤维上的沉积和分散,以促进其石墨化,考察了热处理温度和电解液中钼酸钠浓度对PAN基炭纤维催化石墨化的影响.催化剂的担载状况、纤维的形貌和结构变化等分别通过能量散射谱(EDS)、扫描电子显微镜(SEM)和X射线衍射(XRD)进行分析和表征.结果表明:通过交替直流电解处理,可以有效地破坏炭纤维的组织结构,并同步实现催化剂在炭纤维上的分散和沉积,促进了PAN基炭纤维的催化石墨化.交替直流电解处理过的炭纤维经2 400 ℃热处理后,其石墨化度高达99%,微晶尺寸(L_c)为38 nm.     

Structural characteristics,dispersion, and modification of fibrous brucite

Fibrous brucite has very unique structure and physical properties. Brucite fibers were exfoliated into single nanofibers by using dioctyl sodium sulfosuccinate (AOT) as a dispersant through mechanical agitation and ultrasonic dispersion; and then, the nanofibers were modified by stearic acid and (3-aminopropyl)triethoxysilane (γ-APS) compound modification agent. The nanofibers were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis. It is found that AOT has good effect on the dispersion. The single fiber has a consistent morphology, and fibrous brucite is dispersed and modified without destroying the crystal structure. Infrared and thermal analysis shows that the surface modification of fibrous brucite is achieved by forming chemical bonds between the coupling agent and magnesium hydroxide.     

NdFeB磁性材料化学镀非晶态Ni—W—P合金及其相转变行为

采用化学镀方法在NdFeB磁性材料表面施镀非晶态Ni—W—P合金,利用扫描电子显微镜（SEM）及X射线衍射仪对Ni—WP合金镀层的组织形貌、结构及其相转变行为进行了分析．结果表明,非晶态Ni—W—P合金镀层是由大量不同尺寸的颗粒状或胞状突起组成,随着热处理温度逐渐升高,镀层结构由非晶结构逐渐转变为晶态结构,非晶态Ni—W—P合金镀层的晶化转变温度范围为350～380℃．     

酶改善二次纤维结合性能的研究

以二次纤维为研究对象，分别用半纤维素酶和纤维素酶对其进行处理，以改善二次纤维的结合性能，寻找酶处理的最佳条件．并用扫描电镜(SEM)观察二次纤维处理前后表面形态的变化．研究结果表明，提高纸页强度主要靠改善二次纤维的结合性能．半纤维素酶处理时半纤维素与纤维表面的木聚糖反应，打开半纤维素之间氢键的联结，使纤维表面细纤维化并增加润胀，改善了其结合性能．纤维素酶处理时其C1酶破坏纤维素链的结晶结构，使纤维易于润胀，因此增强了二次纤维的结合性能．     

热氧化对PAN基碳纤维结构与性能的影响

将PAN基碳纤维在于400~700℃条件下空气中进行热氧化处理,然后利用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、密度梯度管和纤维强力仪研究了其表面化学组成、表面形貌与性能的变化。结果表明:热氧化温度低于600℃时,纤维表面含氧量随热氧化温度升高不断增加,到600℃时氧含量增加了7.11%,主要增加的官能团为羟基、醚键以及羰基,纤维体密度、线密度随热氧化温度变化不明显;700℃时由于含氧官能团的裂解,氧含量有所减少,裂解部分主要为羰基,纤维体密度明显增加,线密度急剧减小;纤维强度随热氧化温度升高不断减小,600℃后减小趋势更加明显;模量随热氧化温度变化不明显。