Diethanolamides of Castor Oil as Polyols for the Development of Water-Blown Polyurethane Foam

Castor oil was chemically modified into a diethanolamide by a two step process. The first step was the hydroxylation of double bonds in castor oil and second step was the transamidation using diethanolamine to increase the hydroxyl value. Water blown polyurethane foams were developed with this castor oil based polyol using polypropylene glycol of molecular weight 1,000 as the copolyol and polymeric MDI. The density and mechanical properties namely compression and flexural strength depended on the composition of the foam formulation. The hydroxyamide content and molecular weight of commercial polyol had significant effect on the micro structure as observed by optical microscopy.     

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.     

Morphological and Thermal Characterization of Linseed-Oil Based Polymers from Cationic and Thermal Polymerization

Linseed oil-based polymers have been synthesized via cationic and thermal polymerization and characterized through various techniques, such as SEM, DMA, DSC and TGA. The morphology of the polymer samples after extraction reveals the smooth structure of the polymer matrix. With an increase in oil content, the morphology is observed to be more loosely bound. With an increase in linseed oil content in the samples, the room temperature storage modulus (E′) varies from 10.4 × 10⁷ to 1.8 × 10⁷ Pa. The glass transition temperatures measured through DMA of the cationic samples ranges from 70 to −6 °C and the crosslink densities range from 18.4 × 10³ to 3.4 × 10³ mol/m³. The glass transition temperatures of the thermal samples range from 106 to −4 °C and the crosslink densities range from 7.7 × 10³ to 2.4 × 10³ mol/m³. The TGA results show three stages of degradation of the polymer samples and it is also revealed that these polymers are stable up to 200 °C, showing negligible decomposition.     

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.     

Degradation Study of Biobased Polyester–Polyurethane and its Nanocomposite Under Natural Soil Burial,UV Radiation and Hydrolytic-Salt Water Circumstances

The current study focuses on the development of a formulation of polyester polyurethane (PEPU) samples using castor oil (CO) modified polyester polyol and partially biobased aliphatic isocyanate. The CO modified polyester polyol was synthesized employing transesterification reaction between CO and diethylene glycol in the presence litharge (PbO) catalyst. Subsequently, the modification of CO was confirmed using proton nuclear magnetic resonance (¹HNMR) spectra analysis. In the next stage, the biobased polyester polyurethane nanocomposites (PEPUNC) were prepared by incorporating 3 wt% OMMT nanoclay within PEPU through in situ polymerization technique. The produced PEPU was confirmed by Fourier transform infrared spectroscopy (FTIR) and ¹HNMR spectra analysis. Further, the degradation properties of developed PEPU subjected to soil-burial, UV exposure and hydrolytic-salt water medium were noted by FTIR spectroscopy. Corresponding weight loss, mechanical measurements and morphological studies through scanning electron microscopy (SEM) analysis were studied. The results showed that the addition of OMMT nanoclay within the PEPU matrix produces significant improvement in the degradation rate which indicated the susceptibility of OMMT nanoclay to humidity upon exposure to soil burial. The produced microorganisms from the soil resulted in significant chemical and morphological changes in the entire structure of the PEPU. Additionally, the highest degradation and percentage of weight loss was observed under soil burial as compared to UV exposure and hydrolytic-salt water medium.     

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.     

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.     

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.     

Characteristics of products and PCDD/DF emissions from a pyrolysis process of urethane/styrofoam waste from electrical home appliances

A plastic fraction consisting mainly of polyurethane/styrofoam waste is generated after separating valuable spare parts and metals from used electrical home appliances. In Korea, such waste is currently incinerated in cement kilns or is landfilled. However, owing to its high volatile matter content, conversion into gaseous or liquid pyrolysis products is a preferable alternative. A pyrolysis process of polyurethane and styrofoam waste from electrical home appliances was evaluated by characterizing the products generated at 500°–800°C. The para meters determined were the yields of gas, oil, and char; the characteristics of the remaining char; and the con centration of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzo-furans in the product gas. As expected, the char yield decreased at higher temperatures, whereas gas and oil yields showed increasing tendency. The oil products could be used as storable fuels with a calorific value of 6000–8000 kcal/kg. Fine pores were observed in the char. The adsorption and decolorizing ability of the char were almost the same as those of activated carbon, so that pyrolysis char has potential for use as a sorbent. Further feasibility studies will be needed before utilizing pyrolysis technology to recover either fuels or usable products from polyurethane/styrofoam waste.     

Thermal and Mechanical Properties of Polyurethane Rigid Foam Based on Epoxidized Soybean Oil

A soypolyol based on epoxidized soybean oil (ESO) was prepared in the presence of HBF₄ and diethanolamine (DEA) was used as ring opener. A series of polyurethane rigid foam were prepared by mixing polyol with TDI using an isocyanate index of 1.1. The polyol used in this paper were a mixture of soypolyol and a commercial PL-5601 polyester polyol and the mass fraction of PL-5601 was in the range of 0–60%. The thermal properties of the resins were characterized by DSC and TG. The results showed that these rigid foams possess high thermal stability. There were two glass transition temperature of each foam and Tg₁ was increasing with the increasing of OH value. The compression strength of the foam was also recorded, and the effect of mass ratio of soypolyol and PL-5601 polyester polyol on the compression strength was discussed.     

Treatment of discarded oil in supercritical carbon dioxide for preparation of carbon microspheres

Carbon microspheres with diameter of 1–10 μm were prepared by treatment of waste oil in a supercritical carbon dioxide (scCO₂) system. The structure and morphology of the products were characterized by X-ray diffraction, field-emission scanning electron microscopy, and Raman spectrometry. It is shown that the products consist of graphite microspheres with relatively low graphitization. The yield of solid products increased from 26.8 wt% to 42.2 wt% as the reaction temperature was raised from 530°C to 600°C. Spheres with multilayer structure could be obtained by means of subsequent vacuum annealing of the carbon microspheres at 1500°C. The formation mechanisms of carbon microspheres in the scCO₂ system and the influence of vacuum annealing on the structure are discussed in detail.     

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.     

Thermo-Chemical Decomposition Study of Polyurethane Elastomer Through Glycerolysis Route with Using Crude and Refined Glycerine as a Transesterification Agent

Due to the increasing amount of polyurethane waste, chemical recycling of these materials is a topic of growing interest for many researchers. The primary purpose of polyurethane feedstock recycling is to recover the starting polyol. In this study glycerolysis using glycerine from two sources and two purity grades is proposed as a method of chemical recycling. The main effort of this paper focuses on the employment of commercial glycerine of analytical grade and waste glycerine without purification derived from the biodiesel production, as a decomposing agent for polyurethane recycling. In this study, the influence of polyurethane to glycerine mass ratio (PU/GL) and the type of decomposing agent on the chemical structure by FTIR, ¹H NMR and GPC was examined. FTIR analysis of the glycerolysates showed absorption peaks similar to the virgin polyol. Those results are in compliance with GPC chromatograms, which showed for all samples, well-defined peak at ca. 13 min of retention time. The molecular weight of glycerolysates was ranging from 800 to 1300 g mol^?1 depending on PU/GL mass ratio. The novel decomposition agent, namely waste glycerine derived from biodiesel production was successfully used in glycerolysis process.     

Oil Erosion in an Annular Flume by Seawater of Varying Turbidities: A Critical Bed Shear Stress Approach

Laboratory experiments were conducted in an annular flume using Hibernia crude oil to determine: (1) the critical shear stress (τ_c) necessary to remove stranded oil from a surface by resuspension and (2) the effect of suspended sediment concentrations (SSCs) on the oil erosion processes. Two types of erosion were evident: Type I––solution and erosion of soluble aromatics; and Type II––mass erosion of visible droplets. In particulate free seawater at 13 °C, the Type II erosion threshold τ_cII is 5.0 Pa. This is equivalent to a mean current velocity (U_y) of 0.55 m s⁻¹. At U_y values <0.55 m s⁻¹, Type I erosion occurred as shown by the increase of oil concentrations without visible erosion of the oil surface. Temperature has a strong control on the threshold and rate of oil erosion: the threshold for Type I erosion at 4 °C was higher and erosion rate lower than at 13 °C. No Type II erosion was observed at 4 °C. SSCs also affects the entrainment of oil. Oil erosion was most efficient at moderate SSCs. At very high SSCs, turbulence suppression and drag reduction became effective and oil erosion rate decreased. SSC at 200–250 mg l⁻¹ were observed to give maximum erosion efficiency and is therefore suggested as the optimal concentration for erosion and elimination of heavy crude oil at a water temperature of 13 °C.     

Aminolysis and aminoglycolysis of waste poly(ethylene terephthalate)

This paper describes the chemical degradation of waste poly(ethylene terephthalate) (PET) with polyamines or triethanolamine, the characteristics of the products, and a search for ways to use these products. Solvolysis of the polymer ester bonds was caused by diethylenetriamine, triethylenetetramine, and their mixtures, as well as mixtures of triethylenetetramine and p-phenylenediamine or triethanolamine. Products of aminolysis or aminoglycolysis of PET obtained in reactions performed at 200–210°C (with a molar ratio of the recurrent polymer unit to amine of 1 : 2) have been characterized using nuclear magnetic resonance (NMR). Viscosity and hydroxyl number measurements have been done for PET/triethanolamine products. Substances from aminolytical reactions with polyamines were tested as hardeners for liquid epoxy resins, and the product of polymer aminoglycolysis with triethanolamine was tested as an epoxy resin hardener, e.g., for water-borne paints, and a polyol component for rigid polyurethane foams. The compositions of epoxy resin hardeners have been characterized using DSC and rheometry. Comparative analyses of the hardened epoxy materials have been done on the basis of glass temperature and mechanical properties data, as well as some specific properties of the coating materials and rigid polyurethane foams. Received: September 15, 2000 / Accepted: September 21, 2000     

Behavior of bromine on the thermal decomposition of paper-based phenolic laminate wastes

We investigated the thermal properties and behavior of bromine on the thermal decomposition of paper-based phenolic laminate wastes containing polybrominated flame retardants. The thermal properties of the phenolic laminate wastes were measured with a thermogravimeter and a conduction-type scanning calorimeter (TG-CSC). The weight loss of the wastes on thermal decomposition was mainly in three phases between 40°C and 600°C. The enthalpy (ΔH) of the thermal decomposition was 104 cal/g. The material balance of the decomposition components was measured with batch-type thermal decomposition equipment. The ratios of carbon residue, liquid, and gas on decomposition at 800°C in a vacuum were 37 wt. %, 48 wt. %, and 15 wt. %, respectively. The bromine contents in the carbon residue and liquid were less than 0.02 wt. % and 10 wt. %, respectively. These results are useful both in the carbonization process of these wastes and in the application of carbon residue as carbon materials. Received: August 11, 2000 / Accepted: March 7, 2001     

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.     

A Processing,Characterization and Marine Biodegradation Study of Melt-Extruded Polyhydroxyalkanoate (PHA) Films

A series of polyhydroxyalkanoates (PHA), all containing 1% nucleating agent but varying in structure, were melt-processed into films through single screw extrusion techniques. This series consisted of three polyhydroxybutyrate (PHB) and three polyhydroxybutyrate-valerate (PHBV) resins with varying valerate content. Processing parameters of temperature in the barrel (165–173 °C) and chill rolls (60 °C) were optimized to obtain cast films. The gel-permeation chromatography (GPC) results showed a loss of 8–19% of the polymer’s initial molecular weight due to extrusion processing. Modulated differential scanning calorimetry (MDSC) displayed glass transition temperatures of the films ranging from −4.6 to 6.7 °C depending on the amount of crystallinity in the film. DSC data were also used to calculate the percent crystallinity of each sample and slightly higher crystallinity was observed in the PHBV series of samples. X-ray diffraction patterns did not vary significantly for any of the samples and crystallinity was confirmed with X-ray data. Dynamic mechanical analysis (DMA) verified the glass transition trends for the films from DSC while loss modulus (E′) reported at 20 °C showed that the PHBV (3,950–3,600 MPa) had the higher E′ values than the PHB (3,500–2,698 MPa) samples. The Young’s modulus values of the PHB and PHBV samples ranged from 700 to 900 MPa and 900 to 1,500 MPa, respectively. Polarized light microscopy images revealed gel particles in the films processed through single-screw extrusion, which may have caused diminished Young’s modulus and tensile strength of these films. The PHBV film samples exhibited the greatest barrier properties to oxygen and water vapor when compared to the PHB film samples. The average oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) for the PHBV samples was 247 (cc-mil/m²-day) and 118 (g-mil/m²-day), respectively; while the average OTR and WVTR for the PHB samples was 350 (cc-mil/m²-day) and 178 (g-mil/m²-day), respectively. Biodegradation data of the films in the marine environment demonstrated that all PHA film samples achieved a minimum of 70% mineralization in 40 days when run in accordance with ASTM 6691. For static and dynamic incubation experiments in seawater, microbial action resulting in weight loss as a function of time showed all samples to be highly biodegradable and correlated with the ASTM 6691 biodegradation data.     

A new method for evaluating the sewage sludge pyrolysis kinetics

A new method to simplify calculation the kinetics model is applied to sewage sludge pyrolysis based on the assumption that volatile run out as soon as it formed and during temperature arising process in this study. Difference method widely used to solve math problems is conducted to calculate kinetics parameters. Pyrolysis experiments are carried out at heating rates of 10, 15, 20, and 50 °C/min. All the TG curves are divided into three parts which are beginning decomposition temperature range, main decomposition temperature range, and final decomposition temperature range. The second one is employed to determine the parameters for more than 70% of the total mass loss occurs in this range. According to the developed method, the react order, reaction energy and pre-exponential factor are obtained, which are in the range of 3.9–4.1, 82.3–109.2 kJ/mol and 7.7 × 10⁶–2.8 × 10⁹/min, respectively, which are in the range of that reported previously. As a comparison experimental data with calculated data, the well fitting results indicate that this method is appropriate for simulating sludge pyrolysis kinetics.     

The Properties of Poly(<Emphasis Type="SmallCaps">l</Emphasis>-Lactide) Prepared by Different Synthesis Procedure

Different synthesis methods were applied to determine optimal conditions for polymerization of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione (l-lactide), in order to obtain poly(l-lactide) (PLLA). Bulk polymerizations (in vacuum sealed vessel, high pressure reactor and in microwave field) were performed with tin(II) 2-ethylhexanoate as the initiator. Synthesis in the vacuum sealed vessel was carried out at the temperature of 150 °C. To reduce the reaction time second polymerization process was carried out in the high pressure reactor at 100 °C and at the pressure of 138 kPa. The third type of rapid synthesis was done in the microwave reactor at 100 °C, using frequency of 2.45 GHz and power of 150 W at the temperature of 100 °C. The temperature in this method was controlled via infrared system for in-bulk measuring. The solution polymerization (with trifluoromethanesulfonic acid as initiator) was possible even at the temperature of 40 °C, yielding PLLA with narrow molecular weight distribution in a very short period of time (less than 6 h). The obtained polymers had the number-average molecular weights ranging from 43,000 to 178,000 g mol⁻¹ (polydispersity index ranging from 1 to 3) according to the gel permeation chromatography measurements. The polymer structure was characterized by Fourier transform infrared and NMR spectroscopy. Thermal properties of the obtained polymers were investigated using thermogravimetry and differential scanning calorimetry.