紫外光辐照接枝MMA改性锂离子电池PE隔膜

采用紫外光辐照接枝的方法,通过本体聚合,将甲基丙烯酸甲酯（MMA）接枝至聚乙烯（PE）隔膜表面,以改善其对电解液的润湿性能。结果表明：通过紫外光辐照可实现有效的表面接枝,当引发剂质量浓度为0.10 g/mL,光照时间为150 s时,表面接枝率达到49.15%,通过扫描电镜、原子力显微镜等对膜表面形貌变化进行了观察,静态...     

Self Assembly of the Metal Nanoparticles: Formation of the Highly Oriented,Core-Shell Type,Bimetallic Gold–Silver Film

A synthetic route is presented for the preparation of a bimetallic gold–silver film under UV-irradiation. Methoxy polyethylene glycol, a water soluble polymer, is used as the reducing agent for the gold and silver ions in the presence of a ultra-violet source that results in the formation of gold and silver bimetallic nanoparticles. During stirring a centrifugal force is generated at the center of the solution, which results in a coalescence of the nanoparticles and forms a self-assembly of small subunits that ultimately produces a film-like network. UV–vis spectra and scanning electron microscopy were used to determine, respectively, the configuration of the gold and the silver in the nanoparticles, a Au_core–Ag_shell structure, and the thickness of the film.     

GRAFT COPOLYMERIZATION OF ACRYLAMIDE ONTO THE UV-RAY IRRADIATED FILM OF POLYESTER-POLYETHER

In this paper the Ce(Ⅳ) salt initiated graft copolymerization of acrylamide onto the film of polyesterpolyether block copolymer irradiated by UV-ray was reported. The UV-irradiation of the film and its graft process have been investigated by UV spectrum, ESR and ESCA and the influence of other factors on the graft copolymerization has been discussed.     

Fine Patterning of Transparent, Conductive SnO2 Thin Films by UV-Irradiation

Finely patterned transparent, conductive SnO₂ thin films have been prepared. UV-light from a high-pressure mercury lamp was irradiated through a mask on the precursor films prepared from SnCl₂ with acetyl acetone in the ambient atmosphere, and this irradiation led to the change of solubility of the films in alkaline solution. Patterns with a width of about 3 to 50 m and thickness of about 0.1 m were formed with a pitch of about 2 to 20 m. The resistivity of the films heat-treated at 500°C after UV irradiation was about 1 × 10^–2 cm, which was almost the same resisitivity for the films heat-treated at 500°C without UV irradiation.     

The influence of UV-radiation on hyaluronic acid and its blends with addition of collagen and chitosan

In this paper, the results regarding the influence of UV-irradiation with 254?nm wavelength on the surface and mechanical properties of hyaluronic acid, hyaluronic acid/collagen and hyaluronic acid/collagen/chitosan mixtures are presented. For this study, thin films were prepared by solvent evaporation from solution of HA and mixtures made from HA/Coll and HA/Coll with 30% addition of chitosan. The surface properties of films were investigated by AFM and using contact angle measurements, allowing the calculation of surface free energy and its components. Mechanical properties of films made of biopolymeric blends before and after UV-irradiation have been investigated by mechanical testing machine.     

Surface characteristics of UV-irradiated polyurethane elastomers extended with α, ω-alkane diols

Polyurethane elastomers (PUEs) based on 4,4′-diphenylmethane diisocyanate (MDI), poly (?-caprolactone) (PCL) and extended with series of chain extender (CE) were synthesized via two step polymerization technique. The synthesized samples were irradiated for 50, 100 and 200 h in an UV exposure unit as such the spectral distribution of the light is good match for terrestrial solar radiation. The modifications in the chemical structures of the PU before and after irradiation were characterized using Fourier transform infrared (FT-IR) technique. The effect of irradiation time and chain extenders length on surface properties were studied and investigated. Photo-oxidation of PU surface leads to fast increase in surface free energy and its polar component. Simultaneously, the work of water adhesion to polymer increases significantly during UV-irradiation. The higher changes in surface properties, observed by water absorption (%), equilibrium degree of swelling, as well as monitored by ATR-FT-IR and contact angle measurement, were found for the PU samples extended with higher number of methylene unit and irradiation time.     

Influence of surfactant structures in luminescence enhancement dynamics during nucleation and growth of aqueous ZnS nanoparticles and their photoactivation due to illumination with UV/visible light

Nanostructured semiconductor architectures have attractive optical properties mainly including bright photoluminescence (PL) resulting from the radiative recombination of charge carriers on surface states. Various approaches have been employed for the modification of surface states of these nanostructures to design new nanomaterials with enhanced PL primarily in aqueous medium to enable their applications in biological samples. Here, we report the varying efficiencies of three commercial surfactants viz. cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC) and cetylpyridinium chloride (CPyC) on the dynamics of PL emission enhancement during initial growth and Ostwald ripening of ZnS nanoparticles (NPs). The counterion has been estimated to behave differently to govern the PL enhancement. The exceptionally high tendency of CPyC in PL enhancement has been assigned to participation of π-electrons of pyridinium ring. The impact of UV-light in photoactivation of surfactant stabilized ZnS NPs has been utilized in exploring significance of surfactants in improving the surface emitting states in water soluble semiconductor NPs.     

Chemical and biology aging of novel green membranes made of PVA and wood flour fibers reinforced with nanosilica manufactured by compression molding process

The purpose of this work was to improve the biodegradable properties of polyvinyl alcohol (PVA)/nanowood flour membranes consisting of nanosilica which were manufactured by compression molding process. Cross-linking of PVA was used to improve the mechanical properties and prevent high solubility of the obtained transient membranes. Plasticizer used to increase the plasticity of transient membranes. The biodegradability of transient membranes was evaluated under UV accelerated weathering as well as soil burial test. The transient membranes were characterized by Fourier transform infrared spectra and X-ray diffraction to study the chemical structure. Mechanical strength was appointed to characterize and reveal the mechanical, thermal analysis and the structural properties of such transient membranes. Scanning electron microscope was used to characterize the morphology of transient membranes. Swelling test and weight loss due to biodegradation were also evaluated. The results showed that the developed transient membranes can be used as food packaging bags due to biodegradability (weight loss) under irradiation and during burial soil which making them environmentally friendly.     

溶胶-凝胶光学薄膜的激光损伤研究

 采用溶胶-凝胶工艺制备了SiO₂与ZrO₂单层介质膜，用输出波长1.06μm，脉宽15ns的电光调Q激光系统产生的强激光进行辐照实验。观察了光学薄膜经强激光辐照后的损伤情况，讨论了溶胶 凝胶光学薄膜在强激光照射下的损伤机理，提出了溶剂替换、紫外光处理、添加有机粘接剂等提高溶胶 凝胶光学薄膜激光损伤阈值的方法。     

Property changes in polyoxymethylene (POM) resulting from processing, ageing and recycling

The degradation processes initiated by thermo-mechanical and thermo-oxidative loading as well as exposure to ultraviolet irradiation weathering were examined in commercially available semi-crystalline polyoxymethylene (POM), using predominantly thermo-analytical methods.With reference to different injection moulding conditions and moulding geometries (such as loudspeaker grilles and safety-belt components) it is demonstrated that POM-copolymer chain is not affected, even under higher shear stresses and complicated moulding geometries, if an appropriate additive is used.Thermogravimetric Analysis (TGA) was used to observe stabiliser consumption and further degradation, whereas investigations of melt-flow index and molar mass show effects correlated to late-term changes of the molar mass distribution. Mass-spectrometry investigations performed in parallel to the thermogravimetric analysis identified formaldehyde and carbon dioxide as the main degradation products.Weathering by ultraviolet irradiation results in damage similar to the thermo-oxidative impact.Generally, the copolymers are less sensitive to thermo-mechanical and thermo-oxidative degradations than the homopolymers due to the chain modification. Furthermore, reprocessing results in a decrease of the elongation at break and thermo-oxidative induced degradation proceeds faster for the additional UV-stabilised materials.