Micromechanical deformation processes responsible for toughening mechanisms in ultrafine monospherical inorganic particle-filled polyethylene were investigated in situ by a field-emission gun-environmental scanning electron microscope (FEG-ESEM) with low-voltage techniques. In general, the ultimate properties of polymer composites are largely dependent on the degree of dispersion of filler particles into the matrix. Very often, the agglomeration is one of inevitable occurrences in polymer composites, mixed with ultrafine filler particles. In the present work, the effects of agglomerates, consisting of ultrafine monospherical filler particles, were reexamined in polymer composites on the toughening mechanism. The results show that the dominant micromechanical deformation processes are the multiple debonding processes inside agglomerates, in which the ratio of the matrix strand and the size of agglomerate plays a great role of matrix yielding. In the specimen, where the agglomerates are isolated in the matrix, deformation begins at the equatorial region of agglomerates and propagates through them. However, in the case of closely placed agglomerates, deformation occurs homogeneously within the whole area inside the agglomerates. In both cases, in conjunction with the multiple debonding processes, the major part of energy during the deformation dissipates through the shear-flow processes of the matrix material. In particular, the micromechanical deformation processes observed in this work confirm that the agglomerates do not always have negative effects on the mechanical properties-at least, in the shear deformable semicrystalline polymer matrices. The agglomerates may be effectively used for the improvement of toughness. Furthermore, the FEG-ESEM with low-voltage techniques offers an extremely promising and efficient alternative method to study the morphology as well as in situ micromechanical deformation processes in nonconducting polymer systems.

In this study, castor oil was alcoholyzed with both aliphatic alcohols, such as glycerol and pentaerythritol, and an aromatic alcohol, bisphenol A propoxylate. The resulting alcoholysis products were then malinated and cured in the presence of styrene. Soybean oil pentaerythritol glyceride maleates were also prepared for a direct comparison of the properties of the castor oil and soybean oil based resins. Castor oil was directly malinated as well to see the effect of the alcoholysis step on the properties of the castor oil based resins. The monomers synthesized were characterized by 1 H-NMR spectroscopy, and the styrenated resin liquid properties, such as viscosity and surface energy values, were determined. The conversion of polymerization was determined using time resolved FTIR analysis for the styrenated soybean oil pentaerythritol glyceride maleates, castor oil maleates, and castor oil pentaerythritol glyceride maleates. The effect of monomer identity and styrene content on the conversion of polymerization was explored.

Maleic anhydride modified soybean-and castor-oil-based monomers, prepared via the malination of the alcoholysis products of the oils with various polyols, such as pentaerythritol, glycerol, and bisphenol A propoxylate, were copolymerized with styrene to give hard rigid plastics. These triglyceride-based polymers exhibited a wide range of properties depending on their chemical structure. They exhibited flexural moduli in the 0.8-2.5 GPa range, flexural strength in the 32-112 MPa range, glass transition temperatures (T g ) ranging from 72 to 1528C, and surface hardness values in the 77-90 D range.The polymers prepared from castor oil exhibited significantly improved modulus, strength, and T g values when compared with soybean-oil-based polymers. These novel castor and soybean-oil-based polymers show comparable properties to those of the high-performance unsaturated polyester (UP) resins and show promise as an alternative to replace these petroleum-based materials.

ABSTRACT:In this study soybean oil triglycerides were reacted with maleic anhydride in an ene reaction to introduce more than two maleate residues per triglycerides. The maleinized soybean oil (SOMA) was then polymerized with diols to the half-ester stage only. Two different types of alcohols was used in this work: (1) short-chain polyhydroxy linear or cyclic alcohols having 2, 3, 4, or 6 hydroxyl groups; and (2) long-chain dihydroxy alcohols. The aim was to determine the effect of functionality and chain length by choosing alcohols with increasing number of hydroxyl groups and different chain lengths. The reaction of alcohols with anhydride functionalized soybean oil to give a polymeric halfester is a reaction that proceeds without the formation of byproducts and is different from complete polyesterification of maleinized oils, which are well known. To improve the reaction yields, different catalysts and different reaction conditions were examined. The structural analysis of the products was done with 1 H-NMR and IR spectroscopy. All of the new polymers obtained were resilient and soft rubbers at room temperature. Castor oil polymer mixed with 60% CaCO 3 and 12% cork powder gave a resilient and nontacky linoleum composition.

ABSTRACT:The Ritter reaction of plant oil triglycerides (such as soybean and sunflower oil) with acrylonitrile was used to introduce acrylamide functionality on the triglyceride. Acrylonitrile and triglycerides were reacted in the presence of H 2 SO 4 , and acrylamide derivatives were obtained in yields of 45 and 50% for sunflower oil and soybean oil, respectively. Radical initiated copolymerization of the acrylamide derivatives of the triglycerides with styrene produced semirigid polymers. Characterization of new monomers and polymers was done by 1 H-NMR, 13 C-NMR, IR, and MS. The swelling behavior of the crosslinked network polymers was determined in different solvents. Glass transiton temperature (T g ) of the cured resin was also determined by differential scanning calorimeter to be 40°C for soybean based polymer and 30°C for sunflower-based polymer. Homo-and copolymerization behavior of acrylamide derivatives of methyl oleate (MOA) and methyl 10-undecenoate (MUA) were also investigated. The reactivity ratios of these monomers with respect to styrene were determined by the Fineman-Ross method using 1 H-NMR spectroscopic data. The reactivity ratios were r sty ϭ 1.776; r moa ϭ 0512 for MOA, and r sty ϭ 1.142; r mua ϭ 0.507 for MUA, respectively. Photopolymerization behaviors of MOA and MUA were also investigated using the photoDSC technique and the rate of polymerization of MUA is higher than that of MOA under the same conditions.