Zoran S. Petrović

Bio: Zoran S. Petrović is an academic researcher from Pittsburg State University. The author has contributed to research in topics: Polyurethane & Polyol. The author has an hindex of 50, co-authored 165 publications receiving 9283 citations. Previous affiliations of Zoran S. Petrović include CertainTeed Corporation & University of Massachusetts Amherst.

Polyurethanes from Vegetable Oils

Abstract: Vegetable oils are excellent but very heterogeneous renewable raw materials for polyols and polyurethanes. This review discusses the specific nature of vegetable oils and the effect of their structures on the structure of polyols and polyurethanes. One section is dedicated to polyols for rigid and flexible foams and methods of their preparation such as direct oxidation of oils, epoxidation followed by ring opening, hydroformylation, ozonolysis, and transesterification. The next section deals with preparation and structure‐property relationships in polyurethanes from different groups of polyols, different isocyanates, and different degrees of crosslinking. The final section covers the environmental aspects of bio‐based polyurethanes, i.e., thermal stability, hydrolytic stability, and some aspects of biodegradability.

Thermal stability of polyurethanes based on vegetable oils

Abstract: A series of polyurethanes from polyols derived from soybean, corn, safflower, sunflower, peanut, olive, canola, and castor oil were prepared, and their thermal stability in air and nitrogen assessed by thermogravimetric analysis, FTIR, and GC/MS. Oil-based polyurethanes generally had better initial thermal stability (below 10% weight loss) in air than the polypropylene oxide-based polyurethane, while the latter was more stable in nitrogen at the initial stage of degradation. If weight loss at a higher conversion is taken as the criterion of stability, then oil polyurethanes have better thermal stability both in air and in nitrogen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1723–1734, 2000

Rigid polyurethane foams based on soybean oil

Abstract: Both HCFC- and pentane-blown rigid polyurethane foams have been prepared from polyols derived from soybean oil. The effect of formulation variables on foam properties was studied by altering the types and amounts of catalyst, surfactant, water, crosslinker, blowing agent, and isocyanate, respectively. While compressive strength of the soy foams is optimal at 2 pph of surfactant B-8404, it increases with increasing the amount of water, glycerin, and isocyanate. It also increases linearly with foam density. These foams were found to have comparable mechanical and thermoinsulating properties to foams of petrochemical origin. A comparison in the thermal and thermo-oxidative behaviors of soy- and PPO-based foams revealed that the former is more stable toward both thermal degradation and thermal oxidation. The lack of ether linkages in the soy-based rather than in PPO-based polyols is thought to be the origin of improved thermal and thermo-oxidative stabilities of soy-based foams. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 467–473, 2000

Effect of structure on properties of polyols and polyurethanes based on different vegetable oils

Abstract: We synthesized six polyurethane networks from 4,4-diphenylmethane di- isocyanate and polyols based on midoleic sunflower, canola, soybean, sunflower, corn, and linseed oils. The differences in network structures reflected differences in the composition of fatty acids and number of functional groups in vegetable oils and resulting polyols. The number average molecular weights of polyols were between 1120 and 1300 and the functionality varied from 3.0 for the midoleic sunflower polyol to 5.2 for the linseed polyol. The functionality of the other four polyols was around 3.5. Canola, corn, soybean, and sunflower oils gave polyurethane resins of similar crosslink- ing density and similar glass transitions and mechanical properties despite somewhat different distribution of fatty acids. Linseed oil- based polyurethane had higher crosslinking density and higher mechanical properties, whereas midoleic sunflower oil gave softer polyurethanes characterized by lower Tg and lower strength but higher elongation at break. It appears that the differences in properties of polyurethane networks resulted primarily from different crosslinking densities and less from the position of reactive sites in the fatty acids. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 809 - 819, 2004

Thermal degradation of segmented polyurethanes

Abstract: Thermal degradation of polyurethane samples was studied by a thermogravimetric method. The effect of soft-segment length and soft-segment concentration on activation energy of the degradation process was measured. Three methods of calculation gave activation energies at different stages of the very complex weight loss process. It was shown that at initial stages of the weight loss the process was dominated by hard-segment degradation. Activation energy of the whole process calculated by the Ozawa–Flynn method did not offer clear insight into the structure–stability relationship of polyurethanes. The second method showed that activation energy of the initial stage of degradation increased with decrease in hard-segment length. The Flynn method of calculating activation energy produced fairly constant activation energy of the first 40% degradation, at around 150 kJ/mol, for polymers in the C series. Generally, calculation of kinetic parameters of a complex degradation process as in polyurethanes gives results that are not easy to interpret. It has been shown qualitatively that polymers with higher soft-segment concentration display lower initial weight loss and higher onset temperatures of degradation. © 1994 John Wiley & Sons, Inc.

Chemical Routes for the Transformation of Biomass into Chemicals

Abstract: 3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Conversion of biomass to selected chemical products

Abstract: This critical review provides a survey illustrated by recent references of different strategies to achieve a sustainable conversion of biomass to bioproducts. Because of the huge number of chemical products that can be potentially manufactured, a selection of starting materials and targeted chemicals has been done. Also, thermochemical conversion processes such as biomass pyrolysis or gasification as well as the synthesis of biofuels were not considered. The synthesis of chemicals by conversion of platform molecules obtained by depolymerisation and fermentation of biopolymers is presently the most widely envisioned approach. Successful catalytic conversion of these building blocks into intermediates, specialties and fine chemicals will be examined. However, the platform molecule value chain is in competition with well-optimised, cost-effective synthesis routes from fossil resources to produce chemicals that have already a market. The literature covering alternative value chains whereby biopolymers are converted in one or few steps to functional materials will be analysed. This approach which does not require the use of isolated, pure chemicals is well adapted to produce high tonnage products, such as paper additives, paints, resins, foams, surfactants, lubricants, and plasticisers. Another objective of the review was to examine critically the green character of conversion processes because using renewables as raw materials does not exempt from abiding by green chemistry principles (368 references).

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

Abstract: 5. In Situ Polymerization 3907 5.1. General Polymerization 3907 5.2. Photopolymerization 3910 5.3. Surface-Initiated Polymerization 3912 5.4. Other Methods 3913 6. Colloidal Nanocomposites 3913 6.1. Sol-Gel Process 3914 6.2. In Situ Polymerization 3916 6.2.1. Emulsion Polymerization 3917 6.2.2. Emulsifier-Free Emulsion Polymerization 3919 6.2.3. Miniemulsion Polymerization 3920 6.2.4. Dispersion Polymerization 3921 6.2.5. Other Polymerization Methods 3923 6.2.6. Conducting Nanocomposites 3924 6.3. Self Assembly 3926 7. Other Preparative Methods 3926 8. Characterization and Properties 3928 8.1. Chemical Structure 3928 8.2. Microstructure and Morphology 3929 8.3. Mechanical Properties 3933 8.3.1. Tensile, Impact, and Flexural Properties 3933 8.3.2. Hardness 3936 8.3.3. Fracture Toughness 3937 8.3.4. Friction and Wear Properties 3937 8.4. Thermal Properties 3938 8.5. Flame-Retardant Properties 3941 8.6. Optical Properties 3942 8.7. Gas Transport Properties 3943 8.8. Rheological Properties 3945 8.9. Electrical Properties 3945 8.10. Other Characterization Techniques 3946 9. Applications 3947 9.1. Coatings 3947 9.2. Proton Exchange Membranes 3948 9.3. Pervaporation Membranes 3948 9.4. Encapsulation of Organic Light-Emitting Devices 3948

Surface and Colloid Science

Abstract: 1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Review of biodiesel composition, properties, and specifications

Abstract: Biodiesel is a renewable transportation fuel consisting of fatty acid methyl esters (FAME), generally produced by transesterification of vegetable oils and animal fats. In this review, the fatty acid (FA) profiles of 12 common biodiesel feedstocks were summarized. Considerable compositional variability exists across the range of feedstocks. For example, coconut, palm and tallow contain high amounts of saturated FA; while corn, rapeseed, safflower, soy, and sunflower are dominated by unsaturated FA. Much less information is available regarding the FA profiles of algal lipids that could serve as biodiesel feedstocks. However, some algal species contain considerably higher levels of poly-unsaturated FA than is typically found in vegetable oils. Differences in chemical and physical properties among biodiesel fuels can be explained largely by the fuels’ FA profiles. Two features that are especially influential are the size distribution and the degree of unsaturation within the FA structures. For the 12 biodiesel types reviewed here, it was shown that several fuel properties – including viscosity, specific gravity, cetane number, iodine value, and low temperature performance metrics – are highly correlated with the average unsaturation of the FAME profiles. Due to opposing effects of certain FAME structural features, it is not possible to define a single composition that is optimum with respect to all important fuel properties. However, to ensure satisfactory in-use performance with respect to low temperature operability and oxidative stability, biodiesel should contain relatively low concentrations of both long-chain saturated FAME and poly-unsaturated FAME.