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.

ABSTRACT:In this study, rigid thermoset polymers were prepared from radical copolymerization of the soybean oil monoglyceride maleates with styrene. In the first part of the study, soybean oil monoglycerides (SOMGs) were obtained from the reaction of soybean oil with glycerol at 220 -240°C with an optimization of the reaction to maximize the monoglyceride yield. In the following step, SOMG were reacted with maleic anhydride at temperatures around 100°C to produce the SOMG maleate half esters. Different catalysts and different reaction conditions were examined to increase the maleate half esters' yields. The reactions were followed by IR and 1 H NMR, and the products were characterized by mass spectrometry. In the final step, the radical initiated copolymerization of the SOMG maleates with styrene produced rigid, thermoset polymers. The emulsion copolymerization of the SOMG maleates with styrene was also carried out successfully without the addition of an emulsifier. The obtained polymers were characterized by IR and the crosslinked network structure of the copolymers was examined with the swelling behavior in different solvents. Mechanical properties of the cured resin such as T g , dynamic flexural modulus, and surface hardness were also determined.

Simultaneous addition of bromine and acrylate to the double bonds of fatty acids in triglycerides was achieved. In the first part of the study, methyl oleate was bromoacrylated in the presence of acrylic acid and N-bromosuccinimide as a model compound for the application of the reaction to the triglycerides. Next, soybean oil and high oleic sunflower oil were bromoacrylated by using the same procedure. The products were characterized by GC, IR, 1 H-NMR, 13C-NMR, and mass spectrometry. The bromoacrylation yields for soybean oil and sunflower oil were 75 and 55%, respectively. A rigid thermoset polymer was prepared from the radical copolymerization of bromoacrylated soybean oil with styrene. The bromoacrylated sunflower oilstyrene copolymer showed semirigid properties. The crosslinked network structure of the copolymers was examined by their swelling behavior in different solvents. Glasstransition temperatures were also determined and soybean oil-based polymer and sunflower oil-based polymer showed a glass transition at 55-65 and 20 -30°C, respectively. The storage moduli of the soybean-based and sunflower-based polymers at room temperature were approximately 1.0 ϫ 10 10 and 1.1 ϫ 10 8 Pa, respectively. Photopolymerization was also carried out by using 2,2-dimethoxy-2-phenyl-acetophenone as initiator. The response of the cured polymers to the thermal energy produced by a small flame was also tested by the ignition respond index method according to ASTM D 3713-78 and was found to be 5 B at 2.00 mm.

In this study, an easy and efficient synthesis of unsaturated plant oil triglycerides having isocyanate groups is reported. In the first step of the synthesis, the triglyceride was brominated at the allylic positions by a reaction with N-bromosuccinimide, and in the second step, these brominated species were reacted with AgNCO to convert them to isocyanate-containing triglycerides. At the end of the reaction, approximately 60-70% of the bromine was replaced by NCO groups, and the double bonds of the triglyceride were not consumed. When the amount of AgNCO was increased, the yield also increased. The final products were characterized with IR and 1 H-NMR, and polyurethanes and polyureas were obtained from these fatty isocyanates with alcohols and amines, respectively. The polymers were characterized by differential scanning calorimetry and thermogravimetric analysis. Differential scanning calorimetry curves showed that glycerin polyurethane showed a glass-transition temperature at 198C, castor oil polyurethane showed two glass-transition temperatures at 243 and 368C, and triethylene tetraamine polyurea showed a glass-transition temperature at 318C. Some properties of the polymers, such as the tensile strength and swelling ratios, were also determined. The swelling rate of glycerin polyurethane was higher than that of castor oil polyurethane in dichloromethane. The equilibrium swelling ratio was highest for the castor oil polyurethane. The polyurethanes synthesized in this study had a Young's modulus around 50 kPa and a tensile strength around 0.01 N/mm 2 (100 kPa). The tensile strength of glycerin polyurethane was higher than that of castor oil polyurethane.