Dynamically vulcanized PP/EPDM blends by multifunctional peroxides: Characterization with various analytical techniques

The characterization of peroxide‐cured PP/EPDM TPVs using various spectroscopic techniques is difficult. These techniques are most suited for analysis of solutions, while the PP‐phase does not dissolve in common organic solvents at room temperature. To obtain more insight into the chemistry and reactivity involved between the multifunctional peroxides and EPDM rubber, several characterization techniques were employed. In the present investigation, FTIR, GC‐(FID + MS), HP‐SEC, and element analysis were used to characterize the multifunctional peroxides TBIB and DTBT, before and after the dynamic curing of the EPDM phase. The decomposition products obtained from these multifunctional peroxides are most likely grafted onto the EPDM‐rubber, thereby reducing their volatility and avoiding the common unpleasant smell. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1393–1403, 2005     

Study of various interventions in the façades of a historical building—Methodology proposal,chromatic and material analysis

Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X‐ray spectroscopy (EDS) in addition to scanning electron microscopy (SEM) have been used for determining the color and chemical composition of the architectural elements of the façades of a historical building, which today is the seat of the Diputación Provincial of Cadiz. It dates from 1770 and was built as Custom Headquarters. It is near the port and is almost encircled by the walls of the city. The determination of the color and chemical composition of the materials that provoke this color and the determination of the layers found in the extracted samples from significant zones allow to define the various interventions over the façade and to localize the time in which they were made. This is possible by comparing with graphical registries and historical documentation. The objective is a study of the color of the different façades that the building has had in order to know the history of the building and to choose materials and colors that should be used in a restoration intervention of this historical building. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 382–390, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

GC/FTIR法和GC/MS法联合分析裂解碳五馏份的组成

在两根分离机理完全不同的色谱柱上，即ＨＰ－１０１柱（分配色谱）和Ａｌ３Ｏ２／ＫＣｌＰＬＯＴ柱（吸附色谱），对乙烯装置裂解碳五产品进行了较完全的分离，联合使用毛细管气相色谱－傅立叶红外光谱法和毛细管气相色谱－质谱法进行定性，在氢火焰离子化检测器上得到归一化的定量结果。同时，也推出了两种能分析单体烃及其二聚物组份的裂解碳五组成的色谱方法。     

Polypyrrole–poly(heptamethylene p,p′-bibenzoate) conducting materials. Synthesis and characterization

Polypyrrole–poly(heptamethylene p,p′-bibenzoate) conducting materials, PPy–P7MB/ClO₄, were obtained by anodic coupling of pyrrole into a polybibenzoate inert matrix, using perchlorate anions as dopant agent. P7MB is a main-chain liquid crystalline polybibenzoate with adequate mechanical properties and elastic modulus of 1.4GPa at room temperature. The method of synthesis, galvanostatic or potentiostatic electrodeposition, is responsible for differences in the PPy–P7MB/ClO₄ films electrochemical response. FTIR spectra show the complex structures of P7MB and the composite conducting material. The conductivity of PPy–P7MB/ClO₄ films maintains a relatively high value, σ = 13.74Scm^?1, in spite of the insulating effect of polybibenzoate. Film micrographs reveal the typical cauliflower morphology exhibited by polypyrrole and the evolution of film growth with time.     

The decomposition reaction path of a linear PFPAE under tribological conditions

It has previously been shown using ¹⁹F nuclear magnetic resonance (NMR) spectroscopy that a linear perfluoropolyalkyl ether (PFPAE) fluid undergoes decomposition by a disproportionation reaction mechanism to form acid fluorides when heated in the presence of aluminum chloride. It is shown in this study that the same linear PFPAE fluid decomposes by the same reaction mechanism to form the same acid fluorides when heated at 345°C in the presence of dry air and bearing steels. Then, it is shown that these acid fluorides readily undergo hydrolysis to carboxylic acids when they are exposed to atmospheric moisture. Finally, carboxylic acids were detected in highly stressed linear PFPAE fluids exposed to the atmosphere after recovery from fatigue testing experiments. Therefore, it is concluded that under real tribological conditions, linear PFPAE fluids initially decompose in the presence of bearing steels by a disproportionation reaction mechanism to form acid fluorides which subsequently react with atmospheric moisture to form carboxylic acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

Characterization of polyurethane foams from soybean oil

Modified soy‐based vegetable oil polyols were successfully incorporated as a replacement for conventional polyols to produce flexible slabstock polyurethane foams. The oil was characterized for its hydroxyl value and fatty acid composition. The modified oils had higher hydroxyl values and lower unsaturated acids than regular unmodified oils. Three different modified polyols were used to investigate the reactivity with isocyanates. The effects on the foaming reaction of two different isocyanates, namely TDI and MDI, were investigated. The reactions were also carried out with a mixture of polyols containing synthetic polyols and vegetable oil‐based polyols to delineate the effect of each component. FTIR technique was used to identify the sequence of chemical reactions during the foaming process. The effect of water levels and isocyanate content on the kinetics of the foaming reaction was investigated. Information regarding the formation of hard and soft segments with the varying compositions was obtained. As the water content increased, the amount of the hard segment and urea formation increased in both soy oil polyols and synthetic polyols. Increased synthetic polyols in the mixture increased the rate of reaction and phase mixing due to the availability of primary hydroxyl groups. Scanning electron microscopy (SEM) and small‐angle X‐ray scattering (SAXS) were used to probe the morphology. As the water content increased, the cell size increased. At lower water content a more uniform cell structure was evident and at higher water levels hard domain size increased. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3097–3107, 2002     

Antioxidation Synergism Between ZnDTC and ZnDDP in Mineral Oil

Antioxidation synergistic effects between ZnDTC and ZnDDP in a mineral base oil were investigated by the Rotary Bomb Oxidation Test (RBOT) and the Indiana Stirring Oxidation Test (ISOT). The results indicate that there is strong antioxidation synergism between the two additives. Fourier transmission infrared spectroscopy (FTIR) analyses show that the oxidation products in the tested oils simultaneously containing the two additives are much less than those in the tested oils containing a single additive and the base oil.     

Effect of spin coating on the curing rate of epoxy adhesive for the fabrication of a polymer optical waveguide

Spin coating is a simple process for rapidly depositing thin, solid polymeric films onto relatively flat substrates. Evaporation occurs during spinning of the relatively volatile species in any solution. The curing behavior of spin-coated polymeric film is influenced by the evaporation of any reactive component. An investigation was carried out on a silicon substrate to study the effects of spin coating on the curing behavior of the epoxy adhesive. The degree of curing for both spin and without spin-coated epoxy adhesive was measured by Fourier-transform infrared spectroscopy (FTIR). A slower curing reaction rate was observed for the spin-coated epoxy adhesive. The composition gradient established by solvent evaporation during spinning is responsible for the slower curing reaction rate of the spin-coated epoxy adhesive. From this study, it is proposed to use solvents that are less volatile and allow a greater part of the thinning behavior to occur without significant changes in the fluid properties during the spinning process.     

Infrared spectra of γ‐irradiated poly(acrylic acid)–polyacrylamide complex

Samples of polyacrylamide (PAAm), poly(acrylic acid) (PAA), and their complex were γ‐irradiated at different doses, namely 48, 96, and 144 KGy. The examination of the infrared spectra of these samples showed that there are no significant observable changes in their spectral features apart from slight changes in the intensities of the absorption bands. The analysis of the absorbances ratios (A 1700 cm^?1/A 1450 cm^?1) and (A 1650 cm^?1/A 1450 cm^?1), denoted as R₁ and R₂, respectively, showed that these ratios depend on γ‐doses. It was found that in the case of PAA, R₁ assumed linear increase with increasing the dose to 96 KGy and then showed marked decrease. For the complex, R₁ increased slightly by increasing the dose to 96 KGy and then decreased. For PAAm, although irradiation with 48 KGy increases the values of R₂, irradiation with 96 and 144 KGy decreases its value. On the other hand, for the complex, R₂ suggested slight decrease on irradiation with 48 KGy followed by continued increases with increasing the dose up to 144 KGy. The increase in R₁ and R₂ may be due to crosslinking as a result of the formation of free radicals. The decrease in these ratios after irradiation with 96 KGy may be due to degradation. It was concluded that γ‐irradiation has a lower effect on the complex (i.e., the complex has a structure which is different from those of PAA and PAAm). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1619–1623, 2002     

Dextran–rare earth ion interactions. II. Solid‐state characteristics

The solid‐state characteristics of dextran complexes precipitated from aqueous solutions with three different light‐lanthanoid cations (La³⁺, Ce³⁺, and Nd³⁺) were investigated by spectroscopic and thermal methods. Spectroscopic characterization was realized by the comparative interpretation of the FTIR spectra, and the complexes were found to involve both ligating water and dextran through its O(2) and O(3) atoms. Remarkable spectral changes were noted, particularly with La³⁺, which parallels the previous solution studies. The order of La³⁺ > Ce³⁺ > Nd³⁺ was determined to display the tendency of the Ln³⁺ ion in favor of dextran throughout the competition between water and dextran. The thermal stabilities of the complexes were examined by thermogravimetry (TG), differential TG, and DSC methods. The decomposition steps and temperatures were assigned with respect to the lanthanoid ions used. The TG and DSC results indicated that the complexes are less stable thermally than dextran itself with increasing thermal stabilities in the order of La³⁺ < Ce³⁺ < Nd³⁺ in their anhydrous states. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2168–2174, 2002