Influence of Palm Oil-Based Polyol on the Properties of Flexible Polyurethane Foams

This paper describes the effect of the modification of polyurethane system with palm oil-based polyol on the cell structure and physical?Cmechanical properties of polyurethane foams. Flexible polyurethane foams were prepared by substituting a part of petrochemical polyether-polyol with the palm oil polyol. Selected physical?Cmechanical properties of these foams were examined and compared to the properties of reference foam. The properties such as apparent density, tensile strength, elongation at break, resilience, compressive stress and thermal stability were analyzed. It was found that the modifications of polyurethane formulation with palm oil polyol allow to improve selected properties of final products.     

Ring-Opening Polymerization of Cyclic Esters onto Liquefied Biomass

Ring-opening polymerization of cyclic esters (-caprolactone, -valerolactone, and l-lactide) onto liquefied biomass (LB) was conducted to obtain the polyester-type polyol and to regulate the characteristics of LB. IR and ¹H-NMR spectra of the obtained polyol showed that the polymerization was successfully conducted in the presence of acid catalyst, which is used in liquefaction. The molecular weight (M_w), hydroxyl value, and viscosity were controllable by changing the reaction conditions. Polyester-type polyurethane foams with a wide range of properties were prepared from the obtained polyol with the appropriate combinations of foaming agents.     

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     

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.     

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.     

Structure,Mechanical, Thermal and Fire Behavior Assessments of Environmentally Friendly Crude Glycerol-Based Rigid Polyisocyanurate Foams

In this work, rigid polyisocyanurate foams were prepared at partial substitution (0–70 wt%) of commercially available petrochemical polyol, with previously synthesized biopolyol based on crude glycerol and castor oil. Influence of the biopolyol content on morphology, chemical structure, static and dynamic mechanical properties, thermal insulation properties, thermal stability and flammability was investigated. Incorporation of 35 wt% of crude glycerol-based polyol had reduced average cell size by more than 30% and slightly increased closed cell content, simultaneously reducing thermal conductivity coefficient of foam by 12% and inhibiting their thermal aging. Applied modifications showed also positive impact on the mechanical performance of rigid foams. Increase of crosslink density resulted in enhancement of compressive strength by more than 100%. Incorporation of prepared biopolyol resulted in enhancement of thermal stability and changes in degradation pathway. Up to 35 wt% share of crude glycerol-based polyol, foams showed similar flammability as reference sample, which can be considered very beneficial from the environmental point of view.     

Effects of Wood Fiber and Microclay on the Performance of Soy Based Polyurethane Foams

Various polyurethane (PU) foams were prepared by in situ reaction of isocyanate and soy-based polyol. The effects of wood fiber and microclay on the foam morphologies, mechanical properties and thermal behaviors of PU foams were investigated. NCO index had fundamental impacts on the influences of wood fiber and microclay on the performance of PU foams. The reinforcement behavior of flexible foams was different to that of both semi-rigid and rigid foams. Both fiber and microclay improved the compressive strength at a high NCO index of 140–250, and contributed to relative high decomposition temperatures. Unlike the compressive strength, the tensile strength was decreased due to the amount of hard polyurea formation from secondary reactions at the highest NCO level. In addition, wood fiber had different reinforcement mechanism from microclay. Wood fiber desired to form chemical bonds during foaming while microclay had potential to form physical insertions. This difference was expressed by the change of their thermal degradation temperature.     

Novel Renewable Polyols Based on Limonene for Rigid Polyurethane Foams

Novel renewable polyols based on limonene were synthesized using thiol-ene “click” chemistry. These limonene based polyols were structurally characterized using wet methods (hydroxyl number, acid value and viscosity), gel permeation chromatography and spectroscopic methods. The results indicated that high yield of polyols from limonene based materials can be obtained using thiol-ene reaction. These limonene based polyols were used successfully for preparation of rigid polyurethane foams. These foams had regular shape cells and uniform cell size distribution. Thermal studies on these foams indicated that foams were thermally stable up to 250 °C. The glass transition temperature of the foams was higher than 200 °C. These rigid polyurethane foams had high compressive strength and the highest compressive strength of 195 kPa was observed. These foams have good physical–mechanical characteristics and could be suitable for all the applications of rigid polyurethane foams such as thermal insulation of freezers, storage tanks for the chemical and food industries, and packing materials for food industries.     

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.     

Synthesis and Characterization of Polyols and Polyurethane Foams from PET Waste and Crude Glycerol

In this study, polyethylene terephthalate (PET) waste from post-consumer soft-drink bottles and crude glycerol from the biodiesel industry were used for the preparation of polyols and polyurethane foams. PET waste was firstly depolymerized by the glycolysis of diethylene glycol. The glycolyzed PET oligomers were then reacted with crude glycerol at different weight ratios to produce polyols via a series of reactions, such as esterification, transesterification, condensation, and polycondensation. The polyols were characterized by titration, viscometry, gel permeation chromatography (GPC), and differential scanning calorimetry. Subsequently, polyurethane (PU) foams were made via the reaction between the produced polyols and polymeric methylene-4,4′-diphenyl diisocyanate and were characterized by mechanical testing, scanning electron microscopy, and thermogravimetric analysis. Polyols from crude glycerol and their PU foams were also prepared to compare properties with those of polyols and PU foams from PET and crude glycerol. The influence of aromatic segments existing in glycolyzed PET and glycerol content on the properties of the polyols and PU foams was investigated. It was found that aromatic segments of polyols from glycolyzed PET helped increase their molecular weights and improve thermal stability of PU foams, while high glycerol content in polyols increased the hydroxyl number of polyols and the density and compressive strength of PU foams.     

Scaled-up and economic assessment approach of the split-phase glycolysis process for the recycling of flexible polyurethane foam wastes

The economic viability of the split-phase glycolysis process for the recycling of any kind of flexible polyurethane foam waste employing crude glycerol as cleavage agent has been demonstrated. First, experiments at pilot plant scale were carried out to check that the process can be extrapolated to larger scales. With the goal of scaling-up the process from laboratory scale to pilot plant, geometric similarity criteria were applied together with dynamic similarity for laminar flow in agitated tank reactors. Hence, a pilot plant installation was designed with geometrically similar equipment to those used for lab scale, obtaining analogous results in terms of recovered polyol properties. Then, the basic design of a split-phase glycolysis industrial plant with a capacity for treating 270 Tm per year of flexible PU foams scraps was proposed. Finally, the economic feasibility of such recycling process was confirmed because of the obtention of a Net Present Value (NPV) of 1,464,555€, with an Internal Rate of Return (IRR) of 27.99%, and a payback time between 4 and 5 years.

     

Water-Blown Castor Oil-Based Polyurethane Foams with Soy Protein as a Reactive Reinforcing Filler

To decrease the usage of petroleum based materials, a kind of bio-resource based composite foams were developed with soy protein isolate (SPI) as reactive reinforcing filler in castor oil based polyurethane foams (PUF) prepared by self-rising method using water as a blowing agent. The resulting composite foams were evaluated for their morphology, density, mechanical and biodegradation properties, etc. Fourier transform infrared spectroscopy study exhibited characteristic peaks for SPI and PUF and indicated that the amino groups and hydroxyl groups on SPI reacted with polyphenyl polymethylene polyisocyanates (PAPI) to increase the crosslinking degrees of the composite foams. Densities of the resultant composites were found to increase with increasing SPI content. Mechanical properties of the samples were improved with the increase of SPI content. The compost tests further proved that the composite PUF had better biodegradability than neat PUF. Therefore, this research has provided a simple method of preparing the bio-resource based polyurethane foams, while exploring the potential of using SPI in polyurethane foam applications.     

A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

A new efficient method for the chemical decomposition of polyamide 6.6 by the glycolysis and amino-glycolysis processes was proposed. The glycolysis was conducted using the mass excess of ethylene glycol (EG) as a decomposing agent in the presence of a catalyst. Also, a mixture of EG and triethylenetetramine was used as another decomposing agent in the amino-glycolysis process. The described process of decomposition did not require the use of elevated pressure. The hydroxyl and amine numbers, rheology behavior and the presence of characteristic chemical groups in the obtained glycolysates and aminoglycolysates were determined in order to characterize the reaction products. The decomposition products were defined as non-Newtonian fluids that could be described by suitable mathematical models. The conducted studies showed that the properties of the obtained intermediates depend on the mass excess of the decomposing agent used. The resulting semi-products are suitable for reusing in the synthesis of polyurethanes, which has been confirmed by the exemplary synthesis. In the reaction, 10 and 15 wt% of commercial polyol were replaced with the recovered intermediates.     

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.     

Biocompatible Polyurethane Scaffolds Prepared from Glycerol Monostearate-Derived Polyester Polyol

Biodegradable polyester polyol was synthesized from oleochemical glycerol monostearate (GMS) and glutaric acid under a non-catalyzed and solvent-free polycondensation method. The chemical structure of GMS-derived polyester polyol (GPP) was elucidated by FTIR, ¹H and ¹³C NMR, and molecular weight of GPP was characterized by GPC. The synthesized GPP with acid value of 3.03 mg KOH/g sample, hydroxyl value of 115.72 mg KOH/g sample and M_n of 1345 g/mol was incorporated with polyethylene glycol (PEG) and polycaprolactone diol (PCL diol) to produce a water-blown porous polyurethane system via one-shot foaming method. The polyurethanes were optimized by evaluating glycerol as a crosslinker, silicone surfactant and water blowing agent on tensile properties of polyurethanes. All polyurethanes underwent structural change, and crystalline hard segments of polyurethanes were shifted to higher temperature suggested that hard segments undergone re-ordering process during enzymatic treatment. In terms of biocompatibility, polyurethane scaffold produced by reacting 100% w/w of GPP with isophorone diisocyanate and additives showed the highest cells viability of 3T3 mouse fibroblast (94%, day 1), and MG63 human osteosarcoma (107%, day 1) and better cell adhesion as compared to reference polyurethane produced by only PEG and PCL diol (3T3 cell viability: 8%; MG63 cell viability: 2%). The current work demonstrated GPP synthesized from renewable and environmental friendly resources produced polyurethanes that allows improvement in physico-chemical, mechanical and biocompatibility properties. By blending with increasing content of GPP, the water-blown porous polyurethane scaffold has shown great potential as biomaterial for soft and hard tissue engineering.     

Soybean-Oil-Based Polyisocyanurate Rigid Foams

Polyisocyanurate foams were prepared from polymeric 4,4-diphenylmethane diisocyanate (MDI), soy polyol and polypropylene oxide polyol by varying isocyanate index from 110 to 350. The higher isocyanate index produced polyisocyanurate foams with higher thermal stability, improved flame resistance, tensile strength, higher modulus, and higher glass transition. Soy-based foams displayed better thermal stability, lower flammability, higher rigidity (modulus) and higher compression strength than those based on the propylene oxide polyols of the same molecular weight and functionality.     

Novel polyol initiator from polyurethane recycling residue

Flexible polyurethane foams can be advantageously treated by two-phase glycolysis in order to recover polyols with improved quality. The bottom phase obtained, which contains highly toxic reaction by-products and the excess glycol, presents an environmental and economic problem which should be solved. The main purpose of this work is the development of process for the valorization of these by-products, converting them in non-dangerous and profitable substances. For this process, most of the glycol can be recovered by means of vacuum distillation in order to reuse it in the glycolysis. On the other hand, the vacuum residue, containing the isocyanate part of the glycolysis by-products, was assayed as initiator in the synthesis of new polyols. Propoxylation of the initiator was carried out in different experimental conditions to obtain several polyether-polyols. Rigid polyurethane foams with suitable technical properties were synthesized with those polyols synthesized with the dangerous glycolysis by-products.     

Polyols and Rigid Polyurethane Foams from Cashew Nut Shell Liquid

Cashew nut shell liquid (CNSL) is a natural aromatic oil consisting of a mixture of phenolic structures with a carboxyl group in ortho position and substituted in meta position with a hydrocarbon chain of 15 carbon atoms. The major component of CNSL is anacardic acid (90?%), which is easily decarboxylated to cardanol by distillation. The present work describes the synthesis of new biobased Mannich polyols for rigid polyurethane foams in two steps: synthesis of Mannich bases by reacting phenolic ring of cardanol with N-(2-hydroxyethyl)-1,3-oxazolidine followed by alkoxylation reactions. The polyols were characterized by wet methods (hydroxyl numbers, viscosity, acid value, density, water content, iodine value etc.), spectroscopic methods (FT-IR, ¹H NMR and ¹³C NMR) and by Gel Permeation Chromatography. The Mannich polyols from cardanol are excellent replacements for petrochemical derived Mannich polyols based on nonyl phenol. Cardanol-based polyols were used successfully for the preparation of rigid polyurethane foams of good physical?Cmechanical and fireproofing properties.     

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.     

Chain-Length Shortening of Methyl Ethyl Hydroxyethyl Cellulose: An Evaluation of the Material Properties and Effect on Foaming Ability

During the past century, plastics have become a natural element in our every-day life. Lately however, an awareness about the fossil origin and often non-degradable nature of many plastics is rising. This has resulted in the emergence of some bio-based and/or biodegradable plastics, often produced from renewable resources. One possible candidate for bioplastics production could be found in cellulose. This paper aims at contributing information regarding a cellulose derivative, which could possibly be used in foamed plastics applications. Therefore, the reduction of the chain-length of a methyl ethyl hydroxyethyl cellulose (MEHEC), assessed by size exclusion chromatography, and the effect of chain-length on the foaming behaviour were studied. The foaming was accomplished with a hot-mould technique using aqueous polymer solutions. The generated steam was here used as the blowing agent and important parameters were polymer concentration and solution viscosity. The density of the produced foams was assessed and was in some cases comparable to that of commodity foams. It was found that reducing the chain-length enabled an increase of the initial polymer concentration for the foaming process. This is believed to be beneficial for creating more structurally stable foams of this type.