Palm Oleic Acid Based Alkyds: Effect of the Fatty Acid Content on the Polyesterification Kinetics

The kinetic behavior of polyesterification of the alkyd resins synthesized using glycerol and phthalic anhydride modified with oleic acid from the palm oil at temperatures between 120 and 240 °C was studied. Three alkyds having oleic acid contents of 28, 40, and 65% were prepared by employing fatty acid method. The extent of the polyesterification reaction and average degree of polymerization were monitored by determining the acid number of the aliquot of the reaction mixture at various intervals of time and by measuring the volume of water evolved. Kinetic studies revealed that initial reaction rates followed a second-order kinetics up to certain limit and thereafter deviations were observed. The extent of reaction varied from 77.4 to 86.3% before deviation for all the three samples and exhibited a considerable degree of conversion. The second-order rate constants calculated from the linear part were found to be of the order of 10⁻⁵ g (mg KOH)⁻¹ min⁻¹. Molecular weight of the alkyd samples was determined by GPC; number average molecular weight of the alkyds ranged from 980 to 2,070.     

Ethoxylated Soybean Polyols for Polyurethanes

Soybean polyols prepared by ring opening reactions of epoxidized soybean oil with hydrogen active compounds (water, alcohols, organic or inorganic acids, thiols, hydrogen etc.) have a low reactivity in the reaction with isocyanates because the hydroxyl groups are secondary. This paper presents a simple and convenient method to increase the reactivity of soybean polyols with secondary hydroxyl groups by ethoxylation reactions with the preservation of triglyceride ester bonds. The method uses mild reaction conditions: low alkoxylation temperature of 35–45 °C, low pressure of 0.1–0.2 MPa (15–30 p.s.i.) and a superacid as catalyst (HBF₄). The new soybean polyols have a higher reactivity toward isocyanates in polyurethane formation due to the high percentage of primary hydroxyl groups. The primary hydroxyl content was determined by the second order kinetics of polyol reaction with phenyl isocyanate.     

Ethoxylated Soybean Polyols for Polyurethanes

Soybean polyols prepared by ring opening reactions of epoxidized soybean oil with hydrogen active compounds (water, alcohols, organic or inorganic acids, thiols, hydrogen etc.) have a low reactivity in the reaction with isocyanates because the hydroxyl groups are secondary. This paper presents a simple and convenient method to increase the reactivity of soybean polyols with secondary hydroxyl groups by ethoxylation reactions with the preservation of triglyceride ester bonds. The method uses mild reaction conditions: low alkoxylation temperature of 35–45 °C, low pressure of 0.1–0.2 MPa (15–30 p.s.i.) and a superacid as catalyst (HBF₄). The new soybean polyols have a higher reactivity toward isocyanates in polyurethane formation due to the high percentage of primary hydroxyl groups. The primary hydroxyl content was determined by the second order kinetics of polyol reaction with phenyl isocyanate.     

Sonophotocatalytic Degradation of Chitosan in the Presence of Fe(III)/H2O2 System

The degradation of chitosan by means of ultrasound irradiation and its combination with homogeneous photocatalysis (photo-Fenton) was investigated. Emphasis was given on the effect of additive on degradation rate constants. 24 kHz of ultrasound irradiation was provided by a sonicator, while an ultraviolet source of 16 W was used for UV irradiation. To increase the efficiency of degradation process, degradation system was combined with Fe(III) (2.5 × 10⁻⁴mol/L) and H₂O₂ (0.020–0.118 mol/L) in the presence of UV irradiation and the rate of degradation process change from 1.873 × 10⁻⁹−6.083 × 10⁻⁹ mol^1.7 L s⁻¹. Photo-Fenton process led to complete chitosan degradation in 60 min with the rate increasing with increasing catalyst loading. Sonophotocatalysis in the presence of Fe(III)/H₂O₂ was always faster than the respective individual processes. A synergistic effect between ultrasound and ultraviolet irradiation in the presence of Fenton reagent was calculated. The degraded chitosans were characterized by X-ray diffraction (XRD), gel permeation chromatography (GPC) and Fourier transform infrared (FT-IR) spectroscopy and average molecular weight of ultrasonicated chitosan was determined by measurements of intrinsic viscosity of samples. The results show that the total degree of deacetylation (DD) of chitosan change, partially after degradation and the decrease of molecular weight led to transformation of crystal structure. A negative order for the dependence of the reaction rate on total molar concentration of chitosan solution within the degradation process was suggested. Results of this study indicate that the presence of catalyst in the reaction medium can be utilized to reduce molecular weight of chitosan while maintaining the power of irradiated ultrasound and degree of deacetylation.     

Alkyd-amino resins based on waste PET for coating applications

Waste polyethylene terephthalate (PET) flakes were depolymerized by using propylene glycol (PG) in the presence of zinc acetate as catalyst. Glycolysis reaction products of waste PET obtained by using PET/glycol molar ratio 1/2. Two short oil alkyd resins of high acid values (30-40mgKOH/g) were prepared from phthalic anhydride (PA), glycerin (G), coconut oil fatty acids (COFA) and glycolyzed products of waste PET (PET-based alkyd resins) or glycols (PG) (reference alkyd resins). These alkyd resins were blended with 30%, 40%, and 50% of a commercial urea-formaldehyde, melamine-formaldehyde and urea-formaldehyde/melamine-formaldehyde mixture (1/1 weight ratio) and heated at 140 degrees C. The physical and chemical properties such as drying time, hardness, abrasion resistance, adhesion strength, water resistance, alkaline resistance, acid resistance, gelation time, and thermal oxidative degradation resistance (with thermogravimetric analysis, TGA) of these alkyd-amino resins were investigated. The properties of the waste PET-based resins were found to be compatible with the properties of the reference resins.     

Photosensitized Oxidation of Cyanide in Aqueous Solutions of Photoactive Modified Hydroxyethylcellulose

Novel water-soluble polymeric photosensitizers based on a natural polymer, naphthalene-modified hydroxyethylcellulose (HENC), were obtained and used for the photooxidation of cyanide. The reaction leads to the formation of cyanate. The process occurs via photoinduced electron transfer from CN⁻ to the naphthalene or naphthoquinone polymeric chromophores. The kinetics of the reaction depend on the degree of substitution of HENC, its concentration, and pH of the solution. The polymers can be easily removed after reaction as prolonged irradiation leads to their photodegradation.     

Microwave Assisted Synthesis of Urethane Modified Polyesteramide Coatings from Jatropha Seed Oil

In this study, we have developed urethane modified polyesteramide (UPEA) resin by the condensation polymerization reaction of N,N-bis (2-hydroxy ethyl) jatropha oil fatty amide (HEJA) and itaconic acid to form polyesteramide (PEA). The latter was further reacted with different percentages (16–22%) of toluylene 2,4-diisocyanate (TDI) to prepare UPEA. The structural elucidation of HEJA, PEA, UPEA was carried out by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. The coating was made on mild steel strips. The physico-chemical and physico-mechanical analyses were carried out by standard laboratory methods. The thermal stability of polymer was studied by thermogravimetric analysis. Thermal analyses shows that these coatings can be used safely up to 230 °C. The corrosion protective behavior of UPEA coatings was investigated in acid, alkali, water and xylene. All the coatings exhibited good chemical resistance performance in acid, alkali, saline and organic solvents, while the resin UPEA 20 showed the best performance.     

Emission inventory of deca-brominated diphenyl ether (DBDE) in Japan

Atmospheric emissions of deca-brominated diphenyl ether (DBDE) in Japan were estimated based on the material flow of DBDE products and their emission factors. In 2002, the demand for DBDE in Japan was 2200 ton/year and the stock level was about 60 000 ton. The DBDE flow into the waste stream was estimated to be about 6000 ton/year and the flow out through second-hand product exports was more than 700 ton/year. Home appliance recycling facilities dismantle and crush domestic wastes containing about 600 ton of DBDE annually. Material recycling of crushed plastics is not commonly practiced as yet. Emission factors from plastics processing (2 × 10⁻⁹–1 × 10⁻⁷), textile processing (9 × 10⁻⁷), home appliance recycling (8 × 10⁻⁹–5 × 10⁻⁶), and waste incineration (1 × 10⁻⁷–2 × 10⁻⁶) were estimated using field measurement data. The DBDE emission rate through house dust during the service life of final products (2 × 10⁻⁷–9 × 10⁻⁷ per year) was estimated using the DBDE concentration in dust and the amount of dust in used televisions. Emission factors from previous studies were also used. The estimated total DBDE emission was 170–1800 kg/year. These results suggest the necessity of characterizing emissions during the service life of products, which is essential information for formulating an appropriate e-waste recycling strategy.     

Kinetics and Thermodynamics of Hydrolytic Depolymerization of Polyamide Waste at Various Temperature and Autogenious Pressure by High-Pressure Autoclave

Hydrolytic depolymerization of polyamide waste in water was studied using 0.5 L high pressure autoclave at temperatures of 235, 240, 245, 250 °C and at autogenious pressure 480, 500, 520, and 600 psi (pound per square inch).The reaction rate constant, energy of activation, enthalpy of activation, entropy of activation and equilibrium constant were calculated from the experimental data obtained. The maximum depolymerization (59.2%) of polyamide waste into monomer caprolactum was obtained at 250 °C and 600 psi pressure. The reaction rate constant was obtained on basis of measurement of amine value and residual weight. The depolymerization reaction was found to be pseudo first order with reaction rate constant of the order of 10⁻³ min⁻¹. The enthalpy, entropy and free energy of activation were recorded as 85.75, −0.1354 and 156.59 kJ mol⁻¹ respectively at the experimental conditions for maximum depolymerization of polyamide waste. The thermodynamic equilibrium constant for this hydrolysis reaction was found to be 2.3 × 10⁻¹⁶.     

Chemical Recycling of Polyamide Waste at Various Temperatures and Pressures Using High Pressure Autoclave Technique

Chemical recycling of polyamide waste in water was studied using 0.5 L high pressure autoclave at temperatures of 150, 200, 210, 220,230 and 240 °C and at various pressures of 100, 200, 300, 400, 500, 600 and 700 psi (pound per square inch). Viscosity average molecular weight of the polyamide waste sample was determined by Ostwald method and recorded as 1.928 × 10³. The reaction was found to be first order with velocity constant in order of 10⁻² min⁻¹. The velocity constant and percent conversion of depolymerization reaction at 240 °C and 700 psi pressure were recorded as 2.936 × 10⁻² min⁻¹ and 99.99% respectively. The velocity constant was obtained on the basis of measurement of amine value. Kinetic and thermodynamic parameters such as energy of activation, frequency factor, enthalpy of activation were found to be 10.6 kJ mole⁻¹, 0.3719 min⁻¹ and 6.3 kJ mole⁻¹ respectively, at the optimum conditions for maximum depolymerization of polyamide waste.     

Biodegradable Polyesters and Polyamides From Difunctionalized Lauric and Coconut Fatty Acids

In this work, a major fatty acid from coconut oil was used as starting material in preparing biodegradable polymers. Thus, polyesters and polyamides from varying proportions of monomers, hydroxy- and amino- derivatives of lauric acid were synthesized. Initially, the derivatives were prepared by regioselective chlorination of lauric acid, in the presence of ferrous ions in strong acid medium. Subsequent hydroxylation and amination procedures yielded the hydroxy- and amino- derivatives of lauric acid. These monomers were polymerized in a reaction tube by simple polycondensation method at 220–230 °C for 6–8 h without catalyst. Molecular weight determination using –COOH by end group titration and gel permeation chromatography (GPC) gave an average molar mass of 3,000–5,000 g mol⁻¹ with n = 15–25 monomer units. Thermal properties such as glass transition (T_g) and decomposition (T_d) temperatures were obtained using differential scanning calorimetry (DSC). The same processes of synthesis and determinations above were applied to coconut fatty acids, derived from saponification of coconut oil, and resulted to very similar conclusions. A quick biodegradation assay against fungus Aspergillus niger UPCC 4219 showed that the polymers prepared are more biodegradable than conventional plastics such as polypropylene, poly(ethyleneterepthalate) and poly(tetrafluoroethylene) but not as biodegradable as cellulosic (newsprint) paper.     

Utilization of Natural Oils for Decomposition of Polyurethanes

The model polyurethane foam and model compact polyurethane material were prepared and then decomposed by means of natural oils. Castor oil and fish oil based polyol were used in this study. Optimal conditions for the polyurethane decomposition were found. Temperature 250 °C was necessary for efficient polyurethane decomposition by castor oil whereas 200 °C is sufficient in the case of fish oil based polyol. Prepared products have hydroxyl number in the range of 95–168 mg KOH g⁻¹. During the polyurethane decomposition no cleavage of double bonds in the fatty acid chains of castor oil and fish oil based polyol was observed.     

Development of Thixotropic Coatings Using Dimerized Soybean Oil Fatty Acids: The Case of Polyamide of 1,2-Phenylene Diamine

Soybean oil (SBO) was dimerized and the crude dimer acid product reacted with 1,2-phenylene diamine at 210 ± 5 °C under inert atmosphere to obtain fatty polyamide (FPA). The FPA was used to modify a commercial alkyd resin by reacting a mixture of the alkyd resin with 5 wt% of FPA at 120 °C for 80 min under inert atmosphere. The FTIR spectrum of the FPA modified resin showed evidence of higher degree of H-bonding than was found for the unmodified alkyd. White gloss coatings of 15, 20, 25, and 30% solids were formulated from the modified and unmodified resins and examined for performance with respect to: leveling, sag resistance, drying time, pigment settling, skinning tendency and film hardness. Results showed that the unmodified alkyd coatings exhibited good leveling but poor sag resistance at all solid contents. In contrast, FPA modified alkyd coatings combined good leveling with high sag resistance indicating their thixotropic nature. A strong tendency to pigment settling was observed for unmodified alkyd coatings but was not observed in the FPA modified alkyd coatings. The modified alkyd coatings showed skinning while the unmodified alkyd coatings did not skin. A 30% solids coating formulation of the FPA modified resin showed shorter surface dry time but longer hard dry time than the unmodified alkyd resin coating.     

Nitrogen Budget of a Spruce Forest Ecosystem After Six-year Addition of Ammonium Sulphate in Southwest Sweden

A nitrogen (N) budget was constructed for a period of 6 years (1988–1993) in a Norway spruce stand with current deposition of 19 kg N and 22 kg S ha⁻¹ year⁻¹. The stand was fertilized annually by addition of 100 kg N and 114 kg S ha⁻¹ (NS). Above and below ground biomass, litterfall, fine- root litter production, soil solution and net mineralization were measured to estimate pools, fluxes and accumulation of nitrogen. The average needle litterfall in control (C) and NS plots in 1993 was 2.2 and 2.5 ton ha⁻¹ year⁻¹, respectively. The fine root litter production prior to treatment (1987) was 4.4 ton ha⁻¹ year⁻¹ and after treatment (1993) it was 4.5 and 3.9 ton ha⁻¹ year⁻¹ in C and NS plots, respectively. Net N mineralization in the soil profile down to 50 cm was estimated to be 86 and 115 kg ha⁻¹ year⁻¹ in C and NS plots, respectively in 1992. During the treatment period the uptake of N in the needle biomass in C and NS plots was 29 and 77 kg ha⁻¹ year⁻¹, respectively. No N was accumulated in needles of C plot where the NS plots accumulated 34 kg ha⁻¹ year⁻¹. Of the annually added inorganic N to NS plots 47% was accumulated in the above and below ground biomass and 37% in the soil. N fluxes via fine-root litter production in the C plots were much higher (54 kg ha⁻¹ year⁻¹) than that via litterfall (29 kg ha⁻¹ year⁻¹). The corresponding values in the NS plots were 65 and 43 kg ha⁻¹ year⁻¹, respectively. Most of the net N mineralization occurred in the FH layer and upper mineral soil. It is concluded that fine root litter and litterfall play an important role in the cycling of N. Despite a high N uptake the losses of N in litterfall and fine root litter resulted in an incorporation of N in soil organic matter.     

Viscosity of Soy Protein Plastics Determined by Screw-Driven Capillary Rheometry

Soy protein plastics are a renewable, biodegradable alternative to fossil fuel-based plastic resins. Processing of soy protein plastics using conventional methods (injection molding, extrusion) has met with some success. Viscosities of processable formulations that contain soy protein along with the necessary additives, such as glycerol and cornstarch, have not been reported, but are necessary for extrusion modeling and the design of extrusion dies. Resins consisting of soy protein isolate-cornstarch ratios of 4:1, 3:2, and 2:3 were plasticized with glycerol and soy oil, compounded in a twin screw extruder and adjusted to 10% moisture. The effects on viscosity of added sodium sulfite, a titanate coupling agent and recycling were evaluated using a screw-driven capillary rheometer at shear rates of 100–800/s. The viscosities fit a power-law model and were found to be shear thinning with power-law indices, n, of 0.18–0.46 and consistency indices, m, of 1.1 × 10⁴–1.0 × 10⁵. Power-law indices decreased and consistency indices increased with increasing soy protein-to-cornstarch ratio and in the absence of sodium sulfite. Addition of the titanate coupling agent resulted in increased power-law index and decreased consistency index. Viscosities at a shear rate of 400/s decreased with recycling, except for the 4:1 soy protein isolate to cornstarch formulation, which displayed evidence of wall slip. Power-law indices were unaffected by recycling. Viscosities in the tested shear rate range were comparable to polystyrene and low-density polyethylene indicating soy protein plastics are potential drop-in replacements for commodity resins on conventional plastics processing equipment.     

Trends in Chemical Composition of Wet-only Precipitation at Rural French Monitoring Stations Over the 1990–2003 Period

The long-term monitoring of precipitation and its chemical composition are important for identifying trends in rain quality and for assessing the effectiveness of pollution control strategies. A statistical test has been used to the atmospheric concentrations measured in the French rural monitoring network (MERA) in order to bring out spatio-temporal trends in precipitation quality in France over the period 1990–2003. The non-parametric Mann–Kendall test which has been developed for detecting and estimating monotonic trends in the time series was used and applied in our study at annual values of wet-only precipitation concentrations. The emission data suggest that SO₂ and NO _x emissions decreased (−3.3 and −2.0% year⁻¹, respectively) contrary to NH₃ emissions that increased slightly (+0.2% year⁻¹) over the period 1990–2002 in France. On the national scale, the pH values have a significant decreasing trend of −0.025 ± 0.02 unit pH year⁻¹. and concentrations in precipitation have a significant decreasing trend, −3.0 ± 1.6 and −3.3 ± 0.6% year⁻¹, respectively, corresponding with the downward trends in SO₂ emissions in France (−3.3% year⁻¹). A good correlation (R ² = 0.84) between SO₂ emissions and concentrations was obtained. The decreasing trend of was more significant (−5.4 ± 5.2% year⁻¹) than that of (−1.3 ± 2.4% year⁻¹). Globally, the concentration of the major ions showed a clear downward trend including marine and alkaline ions. In addition, the relative contribution of HNO₃ to acidity precipitation increased by 51% over the studied period.     

Benthic Infaunal Composition and Distribution at an Intertidal Wetland Mudflat

Benthic infaunal communities at Mai Po Inner Deep Bay mudflat, Hong Kong were investigated between August 2002 and August 2003. A total of 55 species belonging to 8 Phyla from more than 99,074 specimens were recorded. The species richness varied between 13 at Station B in August 2002 and 28 at Station D in August 2003 with an average of 21 across the mudflat and the species diversity was low [H′(log₂) = 0.7–3.5 with an average H′ = 2.4]. Seasonal variations were also observed through abundance and biomass across the mudflat among the seasons. The abundance density was between 8,977 individuals m⁻² at Station D in February 2003 and 77,256 individuals m⁻² at Station B in November 2002 and the overall average density was 25,274 individuals m⁻² for the four stations. The benthic infauna were dominated by pollution tolerant species at this wetland mudflat.     

Biodegradation of Epoxy and MF Modified Polyurethane Films Derived from a Sustainable Resource

Mesua ferrea L. seed oil (MFLSO) modified polyurethanes blends with epoxy and melamine formaldehyde (MF) resins have been studied for biodegradation with two techniques, namely microbial degradation (broth culture technique) and natural soil burial degradation. In the former technique, rate of increase in bacterial growth in polymer matrix was monitored for 12 days via a visible spectrophotometer at the wavelength of 600 nm using McFarland turbidity as the standard. The soil burial method was performed using three different soils under ambient conditions over a period of 6 months to correlate with natural degradation. Microorganism attack after the soil burial biodegradation of 180 days was realized by the measurement of loss of weight and mechanical properties. Biodegradation of the films was also evidenced by SEM, TGA and FTIR spectroscopic studies. The loss in intensity of the bands at ca. 1735 cm⁻¹ and ca. 1050 cm⁻¹ for ester linkages indicates biodegradation of the blends through degradation of ester group. Both microbial and soil burial studies showed polyurethane/epoxy blends to be more biodegradable than polyurethane/MF blends. Further almost one step degradation in TG analysis suggests degradation for both the blends to occur by breakage of ester links. The biodegradation of the blends were further confirmed by SEM analyses. The study reveals that the modified MFLSO based polyurethane blends deserve the potential to be applicable as “green binders” for polymer composite and surface coating applications.     

Formation and decomposition of tetrafluoroborate ions in the presence of aluminum

The formation and decomposition of tetrafluoroborate ions (BF₄⁻) in H₃BO₃-Al³⁺-F⁻ solutions were investigated via experiments and thermodynamic calculations. The concentration of the formed BF₄⁻ increased with decreasing pH, raising the total fluoride concentration and lowering the total aluminum ion concentration. Once formed, BF₄⁻ was stable under neutral and alkaline conditions. Fluoride in the form of BF₄⁻ was converted to fluoroaluminate ions by adding an aluminum compound under acidic conditions. A method for removing fluoride in the form of BF₄⁻ is proposed whereby fluoroaluminate ions formed by the reaction of BF₄⁻ with aluminum are decomposed with calcium ions. This process was applied to the treatment of wastewater from flue gas desulfurization plants, and resulted in a satisfying level of reduction in the range of the fluoride emission limit of 8 mg/l.     

Thermal Stability and Degradation of Chitosan Modified by Acetophenone

N-(Methylphenylmethylidenyl) chitosan (MPMC) polymer was synthesized by chemical modification of chitosan. The chemical structure of the modified polymer was characterized by IR, ¹H NMR and elemental analysis. Thermogravimetric reveals that the thermal stability of chitosan polymer is greater than MPMC polymer. The activation energies of thermal degradation of chitosan and MPMC polymers determined using Arrhenius relationship. Thermal degradation of MPMC polymer was studied and the products of degradation were identified by GC–MS technique. It seems that the mechanism of degradation of MPMC polymer is characterized by elimination of low-molecular weight radicals. Combination or recombination of H^· or OH⁻ with these radicals and random scission mechanism along the backbone chain are the main source of the degradation products.