Effect of Cholesteric Liquid Crystalline Compounds on the Radical Polymerization of Methyl Methacrylate

Polymerization of methyl methacrylate was carried out at 55 and 65°C using benzoyl peroxide as initiator in the presence of the fol-lowing additives: (a) cholesteric compounds like cholesterol, cho-lesteryl acetate, cholesteryl caprylate, cholesteryl stearate, choles-teryl chloride, cholesteryl laurate, cholesteryl oleyl carbonate, and cholesteryl 2-ethylhexyl carbonate, (b) a nematic liquid crystal, N-(p-methoxy benzylidene)-p-butyl aniline, and (c) rodlike molecules like 2-butynediol and diacetylene diol. The rates of polymerization, activation energies, molecular weights, and tacticities of the poly-mer are discussed in the light of monomer + additive interactions. It is found that monomer-additive complexes affect the polymerization rates.     

Cross‐linked waterborne alkyd hybrid resin coatings modified by fluorinated acrylate‐siloxane with high waterproof and anticorrosive performance

Waterborne alkyd resin coatings are ideal for use as corrosion protection coatings because of its high cost‐effective and environmental advantages. However, their uses are restricted to general applications due to their poor acid, water, and alkali resistance. In this work, waterborne alkyd hybrid resins modified with fluorinated acrylate‐siloxane were synthesized via a surfactant‐free miniemulsion polymerization process using maleic anhydride and silicon modified alkyd resin, dodecafluoroheptyl methacrylate, methyl methacrylate, and butyl acrylate as monomers. And then, crosslinking alkyd resin films were prepared at room temperature using trimethylolpropane‐tris‐(β‐N‐azir‐idinyl) propionate (XR‐100) as the crosslinking agent. The acquired films had lower water absorption and higher water contact angles and had better mechanical/thermal properties, as well as good waterproof property. Most importantly, the electrochemical corrosion studies revealed that the cross‐linked coating exhibited superior corrosion resistance performance with an inhibition efficiency of 99.95% and a corrosion rate of 6.95 × 10^?3 mm per year.     

Thermal characterization of carbonate rocks,Kozani area,North-western Macedonia,Greece

The curing of a thermoreactive alkyd-melamine-formaldehyde resin system was investigated by rheologycal, TG and TMA-analysis, in order to construct the time-temperature-transformation diagram. The points of the gelation curve were determined by measuring the increase in viscosity during isothermal curing at different temperatures. A power-function could be fitted to the gelation curve, which is suitable to estimate gelation at any curing conditions, as well as to establish storage conditions. The reaction in the resin matrix was followed by monitoring the loss of mass during isothermal curing at different temperatures. The final section of the resulted iso-curing temperature (iso-T _cure) diagrams could be fitted with logarithmic functions, which may be used for estimating the conditions needed to a given, desirable mass loss, i.e. conversion. The steepness of the curves increases with temperature suggesting the forthcoming of degradation during cure with increasing temperature. From these data the iso-mass loss curves of the TTT-diagram were constructed. For determining the iso-Tg curves of the TTT-diagram isothermal curing was carried out in a drying oven at different temperatures, followed by TMA measurements. The iso-Tcure diagrams served to determine T _{g ￥}, and to construct the iso-T _g curves of the TTT diagram. Vitrification curve is far beyond conditions of storage, curing and degradation, meaning that the resin matrix is in rubbery physical state before, during and after the cure. Curing conditions resulting degradation can also be estimated from the TTT-diagram. This revised version was published online in August 2006 with corrections to the Cover Date.     

Characterization of alkyd based thermosetting resins

The rate of cure of different oxidative drying oil modified alkyd resins are investigated by DSC, when the cure is made under UV light or not. We determine, from the Kissinger equation, the apparent activation energy at different stages of the curing process. This activation energy depends on the curing conditions (temperature, illumination or not). These variations lead to the determination of a time constant, characteristic of the curing kinetics. Two particular values of the apparent activation energy are also defined. The first one called ΔE _o is a characteristic of the varnish at the liquid state, the second one called ΔE _inf characterizes the stability of the structural state of the final film.     

Alkyd-based-thermosetting resin

In this work, the rate of cure of different oxidative drying oil modified alkyd resins are investigated by DSC measurements. We determine, from the Kissinger equation, the apparent activation energy of the curing process. We show that this activation energy depends on the curing duration and that these variations lead to the determination of a time constant, characteristic of the material.     

Analysis of questioned documents: A review

During the last years (2000–2014), many publications concerning the forensic analysis of questioned documents have been published, and new techniques and methodologies are nowadays employed to overcome forensic caseworks. This article reviews a comprehensive collection of the works focused on this issue, including dating studies, the analysis of inks from pens and printers, the analysis of paper, the analysis of other samples related to questioned documents and studies on intersecting lines. These sections highlight the most relevant analytical studies by a wide range of analytical techniques. Separation and spectrometric techniques are critically discussed and compared, emphasizing the advantages and disadvantages of each one. Finally, concluding remarks on the research published are included.     

新型萜烯马来酸酐醇酸树脂的合成与结构表征

利用廉价工业松节油与顺丁烯二酸酐、多元醇。油酸等原料,合成了一种色泽浅,性能良好的萜烯马来酸酐醇酸树脂。研究了合成反应条件,用FTIR谱、^1^HNMR、TGA等手段对产物结构进行了表征,并测定了树脂的性能。     

裂解同时烷基化气相色谱/质谱鉴定醇酸树脂

 用裂解同时烷基化气相色谱-质谱联用技术（SPM-GC-MS）对不同类型的醇酸树脂进行分析研究,将衍生化试剂四甲基氢氧化胺与样品同时裂解,经高效毛细管气相色谱分离,质谱鉴定,可区分醇酸树脂中的多元醇、多元酸、植物油类型,由此对改性醇酸树脂作结构鉴定。与直接裂解-气相色谱-质谱联用技术比较,具有样品前处理快速、简单,用量少,灵敏度高,定性准确,谱图直观等特点。     

Polyurethane Dispersions Based on Sardine Fish Oil,Soybean Oil,and Their Interesterification Products

Alkyd resins were synthesized from different ratios of sardine fish oil and soybean oil. Three alkyd resin samples were styrenated. The styrenated alkyd resins and alkyd resins were subsequently converted into the polyurethane dispersions. The physicochemical properties, such as iodine value, saponification value, and specific gravity were determined. Infrared spectroscopy and nuclear magnetic resonance techniques were used for structural elucidation of newly synthesized resins. The coating properties, such as adhesion, flexibility, scratch hardness, pencil hardness, impact, solvent, and chemical resistance were evaluated. Thermogravimetric analysis was used to investigate the thermal stability of alkyd resin and polyurethane dispersions. Cost effective volatile organic components (VOC) compliant coatings for various applications can be synthesized successfully by partly replacing soybean oil with commercially available, inexpensive sardine fish oil.