A new morphology of crew-cut aggregates prepared from highly asymmetric triblock copolymers of 5-(N,N-diethylamino)isoprene and styrene in dilute solution is reported. After quaternization of the polar block, using dimethyl sulfate, the copolymers consist of a long block of polystyrene (PS) with short poly[5-(N,N,N-diethylmethylammonium)isoprene] (PAI) blocks at both chain ends. The aggregates were prepared by first dissolving the copolymers in a common solvent for both blocks and then adding water to induce the segregation of the PS chains. 1,4-Dioxane, THF, or a DMF/THF mixture was used as the common solvent in the preparation of these structures. The bowl-shaped aggregates are essentially highly polydisperse spheres, containing an asymmetrically placed single void space, which has broken through the surface. The continuous phase is composed of an assembly of reverse micelles (PAI core and PS corona) with hydrophilic PAI chains surrounding the structure at the polymer/aqueous solution interface. It is believed that the formation of the bowl-shaped morphology is under kinetic control and does not represent an equilibrium state. A possible mechanism for the formation of this aggregate is proposed, based on two other previously reported crew-cut morphologies from diblock copolymers. This study illustrates the importance of the preparative conditions on the self-assembly of nonequilibrium aggregates from amphiphilic block copolymers.

Mechanical and thermal properties of materials prepared by curing epoxidized soybean oil with various cyclic acid anhydrides in the presence of tertiary amines were investigated by dynamic mechanical thermal analysis and thermogravimetry. All samples presented thermoset material characteristics that were dependent upon the type of anhydride, the anhydride/epoxy molar ratio, and epoxy group content. The thermosets obtained from anhydrides with rigid structures as such phthalic, maleic, and hexahydrophthalic showed higher glass transition temperatures (Tg) and cross-linking densities. As expected, the Tg decreased as the anhydride/epoxy ratio decreased. The influence of the degree of epoxidation of soybean oil on the mechanical properties and Tg was also investigated. It was found that the higher the epoxy group amount, the higher the Tg and hardness. Cured resins exhibited thermal stability up to 300°C, except for those prepared with dodecenylsuccinic anhydride, which began to decompose at lower temperature. They presented excellent chemical resistance when immersed in 1% wt/vol NaOH and 3% wt/vol H 2 SO 4 solutions but poor chemical resistance in the presence of organic solvents.Vegetable oils represent an interesting renewable source for the production of useful chemicals and new materials (1). Soybean oil is readily available in bulk and is mainly composed of TG molecules derived from unsaturated acids, such as oleic acid (22%), linoleic acid (55%), and linolenic acid (7%). Although unsaturated acids possess double bonds, which are the reactive sites for coatings and paints, they need to be functionalized by the introduction of epoxy, hydroxyl, or carboxyl groups in order to be used for preparation of polymeric materials.Soybean oil can be epoxidized by different methods (2-4) yielding conversions and selectivities higher than 90%. Industrially, it is used mainly as a polyvinyl chloride additive to improve stability and flexibility. New applications have been made possible by the use of photochemically initiated cationic curing (5) and by the preparation of thermosetting materials such as epoxy resins.Epoxy resins are widely used as adhesives and as matrices in composite materials because of their good physical and chemical properties. Toughness and other properties of epoxy resins can be significantly improved by the modification of classical epoxy resins, such as those based on diglycidylether of bisphenol A (DGEBA). Epoxidized vegetable oils prepared from the most unsaturated oils, e.g., soybean oil or linseed oil, can be used for such purpose.In this work we report dynamic mechanical properties of different materials prepared by curing fully and partially epoxidized soybean oil (ESO) with various cyclic acid anhydrides in the presence of tertiary amines. Thermal and chemical resistance were also investigated. MATERIALS AND METHODSPhthalic anhydride (PA), hexahydrophthalic anhydride (CH), maleic anhydride (MAL), and N,N′-dimethylaniline (ARO) were purchased from Aldrich Chemical Co. (Milwaukee, WI) and purif...

Soybean oil and castor oil were modified and used to prepare rigid polyurethane foam with similar properties to a commercial foam used for thermal insulation applications. Soybean oil was firstly modified according to a peracid method, using formic acid and hydrogen peroxide to yield a formiated soy polyol. Furthermore, transesterification was performed with a polyfunctional alcohol to increase OH-functionality. Castor oil, which has hydroxyl groups in the molecular structure, was only transesterified. The vegetable polyols were characterized by OHnumber, Brookfield viscosity, differential scanning calorimetry, and size exclusion chromatography. The foams were prepared at constant NCO/OH ratio (1.2 : 1) by the hand mix method and poured into a closed steel box. They were characterized using scanning electron microscopy, thermogravimetric analysis, and dynamic mechanical analysis. The apparent density and the compression strength of foams were determined, respectively, by the mass/volume relation and through the table tensile tester. After modification, the polyols reached an OH-number between 393 and 477 mg KOH/g oil, showing a low viscosity and molecular weight, allowing the preparation of a rigid vegetable foam with an apparent density of 50 6 1 kg/m 3 and compression strength around 200 kPa. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: [530][531][532][533][534][535][536][537] 2011

Niobium pentoxide could be used to produce adhesive resins with enhanced properties.

Polyurethanes can be prepared using polyols obtained from vegetable oils in natura, such as castor oil, or from functionalized vegetable oils, such as hydroxylated soybean oil. These polyurethanes have different valuable properties, determined by their chemical composition and cross-linking density. In this study, soy epoxy polyols with different OH contents were prepared through a one-step reaction using the method of in situ performic acid generation. Polyols with OH functionalities from 1.9 to 3.2 were reacted in bulk with different diisocyanates at a NCO/OH molar ratio of 0.8 and 60°C for 24 h. Mechanical properties of the polyurethanes were determined by dynamic mechanical thermal analysis, hardness (Shore A), and swelling measurements. Polymer networks with glass-transition temperatures (T g ) from -13 to 48°C were obtained. We observed that the higher the OH functionality of the polyols, the higher the T g and cross-linking density of the polyurethane network. The influence of diisocyanate structure (rigid or flexible chain), curing temperature, and curing reaction time on mechanical properties was also investigated.Paper no. J10956 in JAOCS 82, 365-371 (May 2005). KEY WORDS:Hydroxylated soybean oil, mechanical properties, polyurethane, soy epoxy polyol.The use of renewable resources has attracted the attention of many researchers because of their potential to replace petrochemical derivatives (1-3). Soybean oil is an inexpensive, readily available, renewable resource and provides an excellent platform for polymeric materials. Soybean oil is mainly composed of TG molecules derived from unsaturated FA such as oleic acid (22%), linoleic acid (55%), and linolenic acid (7%). Although they possess double bonds, which are the reactive sites for coatings and paints, they need to be functionalized to prepare polymers (4). Polyurethanes (PU) have been prepared from vegetable oils in natura, such as castor oil, or from polyols obtained from vegetable oils, such as corn, sunflower, and soybean oils, and show a number of excellent properties because of the hydrophobic nature of TG (5,6). To use natural oils as raw materials for PU production, multiple hydroxyl functionalities are required. Usually these are obtained by reacting epoxidized oils with low-M.W. mono-or polyfunctional alcohols or acids.Recently, Petrovic et al. (7) reported the effect of the NCO/OH molar ratio on soy-based PU network properties using a methoxylated soy polyol (OH functionality = 3.7) and 4,4′-methylenebis(phenyl isocyanate) (MDI). Glassy polymers were produced when the NCO/OH ratio was between 0.8 and 1.05. Higher cross-linking densities, glass-transition temperatures (T g ), and tensile strengths were observed as the NCO/OH ratio increased. The influence of the diisocyanate structure on the properties of these soy-based PU was also investigated (8).Guo et al. (9) reported the physical and mechanical properties of soy polyol-derived PU prepared by the hydrogenation of hydroformylated soybean oil. When the hydroformylation reaction was rhod...

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Six fillers from forestry wastes (wood, bark, cones and needles from young pine trees, kraft lignin, and recycled paper sludge from industry wastes) were incorporated into polyurethane (PU)‐based foams prepared via free‐rise pouring method. Variable filler contents (1, 5, and 10 wt %) and NCO/OH ratios (0.6, 0.9, and 1.2) were investigated. A simple mixture (1:3) of castor oil and crude glycerin (byproduct from biodiesel production) was used as biobased polyol. The foam composites were investigated through spectroscopy, morphological, mechanical, and hygroscopic analyses. The addition of fillers decreased water uptake and yielded rigid PU systems with more homogenous cell structure. The 1% and 5% reinforcement wood were the most effective among the studied compositions, with better mechanical and hygroscopic performance, probably due the higher compatibility of the wood with the PU system, which promote urethanic bonds between filler and isocyanate, as indicated by wet chemical results and micrographs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45684.

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