Bio-based polyurethane foams toward applications beyond thermal insulation (original) (raw)
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Journal of Renewable Materials, 2018
This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foams from biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate) (PET) were used to synthesize PU polyols. Addition of adipic acid (ADA) to polyol resulted in improved thermal and viscoelastic properties of foam materials. ADA content was varied from 1 to 6 wt%. Results of the dynamic mechanical spectra indicate an increase of the storage modulus E′ and the loss modulus E″ in the whole temperature range for specimens with higher loading of ADA. In addition, damping factor shifted to higher temperatures, but damping intensity remained almost unaffected by the compositions. Scanning electron microscopy of the foams' cross sections testified that the average cells' size of 110 mm was unaffected by the ADA content in polyol.
Industrial Crops and Products, 2018
In the present work, we report on rigid polyurethane foams (PUR) prepared using three rapeseed oil-based polyols with different chemical structures. The first and the second polyols were made following the transesterification and transamidization methods, whereas the third one was prepared through epoxidation and a ringopening reactions. The rapeseed oil-based PUR foams were next compared with reference foams obtained using polyether petrochemical polyols. The diversity of the chemical structures of the bio-polyols allowed an evaluation of the effect of the bio-component's structure on the properties of the foams obtained. It was noticed that the structures of the bio-polyols have a significant effect on the reactivity of the resultant polyurethane systems. The formulations modified with the bio-polyol containing amine groups were the most reactive and exhibited a faster decrease of the dielectric polarization than the formulations based on the bio-polyol obtained in the epoxidation and ring-opening reactions. The apparent densities of the rigid polyurethane foams were comparable −ca. 36-38 kg/m 3. The PUR foams based on the bio-polyol obtained by the transesterification method were characterized by the lowest content of closed cells. A replacement of a petrochemical polyol with each of the rapeseed oil-based bio-polyols used increased the brittleness of the foams obtained. The values of the thermal conductivity coefficient increased vs the ageing time (24 h, 7 days, 30 days, 3 months and 3 years). The highest values of the thermal conductivity after different ageing times were noticed for the materials modified with the bio-polyol obtained in the transamidization reaction. The rigid polyurethane foams based on the bio-polyol obtained in the two-step methods were characterized by more beneficial mechanical properties. As far as the thermal stability and flammability are concerned, more favourable properties were noticed for the foams modified with the products of the rapeseed oil transamidization and transesterification reactions.
The Use of Biodiesel Residues for Heat Insulating Biobased Polyurethane Foams
International Journal of Polymer Science
The commercial and biobased polyurethane foams (PUF) were produced and characterized in this study. Commercial polyether polyol, crude glycerol, methanol-free crude glycerol, and pure glycerol were used as polyols. Crude glycerol is byproduct of the biodiesel production, and it is a kind of biofuel residue. Polyol blends were prepared by mixing the glycerol types and the commercial polyol with different amounts, 10 wt%, 30 wt%, 50 wt%, and 80 wt%. All types of polyol blends were reacted with polymeric diphenyl methane diisocyanates (PMDI) for the production of rigid foams. Thermal properties of polyurethane foams are examined by thermogravimetric analysis (TGA) and thermal conductivity tests. The structures of polyurethane foams were examined by Fourier Transformed Infrared Spectroscopy (FTIR). Changes in morphology of foams were investigated by Scanning Electron Microscopy (SEM). Mechanical properties of polyurethane foams were determined by compression tests. This study identifies...
Polyurethane Foams from Cellulosic Waste and Natural Oil-based Polyols – a Modified Approach
Polymers from renewable resources, 2013
A modified approach was used to prepare polyurethane (PU) foams employing natural oil-based polyols. Functionalized polyols with different hydroxyl values were synthesized from glycoside obtained from waste paper and reacted with natural oils viz. castor oil and soy oil. The obtained polyols were used to prepare the TDI-adduct based foams. Their physical and thermal properties were studied and compared using compression tests and thermogravimetric analysis; their cellular structures were also investigated using scanning electron microscopy. Processing parameters such as cream, rising and gel times were determined for the reactivity of the prepared polyols. Confirmation of PU linkage was performed by FTIR. The prepared PU foams demonstrated compressive properties ranging from 0.2 to 1.2 MPa and microscopic studies of the foam cell structure indicated its possible use for insulation purposes.
Scientific Reports, 2024
The increasing interest in polyurethane materials has raised the question of the environmental impact of these materials. For this reason, the scientists aim to find an extremely difficult balance between new material technologies and sustainable development. This work attempts to validate the possibility of replacing petrochemical polyols with previously synthesized bio-polyols and their impact on the structure and properties of rigid polyurethane-polyisocyanurate (PUR-PIR). To date, biobased polyols were frequently used in the manufacturing of PU, but application of bio-polyols synthesized via solvothermal liquefaction using different chains of polyethylene glycol has not been comprehensively discussed. In this work, ten sets of rigid polyurethane foams were synthesized. The influence of bio-polyols addition on foam properties was investigated by mechanical testing, thermogravimetric analysis (TGA), and cone calorimetry. The structure was determined by scanning electron microscopy (SEM) and a gas pycnometer. The tests revealed a significant extension of foam growth time, which can be explained by possible steric hindrances and the presence of less reactive secondary hydroxyl groups. Moreover, an increase average size of pores and aspect ratio was noticed. This can be interpreted by the modification of the cell growth process by the introduction of a less reactive bio-polyol with different viscosity. The analysis of foams mechanical properties showed that the normalized compressive strength increased up to 40% due to incorporation of more cross-linked structures. The thermogravimetric analysis demonstrated that the addition of bio-based polyols increased temperature of 2% (T 2%) and 5% (T 5%) mass degradation. On the other hand, evaluation of flammability of manufactured foams showed increase of total heat release (HRR) and smoke release (TSR) what may be caused by reduction of char layer stability. These findings add substantially to our understanding of the incorporation of bio-polyols into industrial polyurethane systems and suggest the necessity of conducting further research on these materials.
Polymers, 2019
This article raised the issue of studies on the use of new bio-polyol based on white mustard seed oil and 2,2’-thiodiethanol (3-thiapentane-1,5-diol) for the synthesis of rigid polyurethane/polyisocyanurate (RPU/PIR) foams. For this purpose, new formulations of polyurethane materials were prepared. Formulations contained bio-polyol content from 0 to 0.4 chemical equivalents of hydroxyl groups. An industrial flame retardant, tri(2-chloro-1-methylethyl) phosphate (Antiblaze TCMP), was added to half of the formulations. Basic foaming process parameters and functional properties, such as apparent density, compressive strength, brittleness, absorbability and water absorption, aging resistance, thermal conductivity coefficient λ, structure of materials, and flammability were examined. The susceptibility of the foams to biodegradation in soil was also examined. The increase in the bio-polyol content caused a slight increase in processing times. Also, it was noted that the use of bio-polyol...
Molecules (Basel, Switzerland), 2017
Rigid polyurethane foams were synthesized using a renewable polyol from the simple physical mixture of castor oil and crude glycerol. The effect of the catalyst (DBTDL) content and blowing agents in the foams' properties were evaluated. The use of physical blowing agents (cyclopentane and n-pentane) allowed foams with smaller cells to be obtained in comparison with the foams produced with a chemical blowing agent (water). The increase of the water content caused a decrease in density, thermal conductivity, compressive strength, and Young's modulus, which indicates that the increment of CO₂ production contributes to the formation of larger cells. Higher amounts of catalyst in the foam formulations caused a slight density decrease and a small increase of thermal conductivity, compressive strength, and Young's modulus values. These green foams presented properties that indicate a great potential to be used as thermal insulation: density (23-41 kg·m(-3)), thermal conductivit...
Journal of Applied Polymer Science, 2014
Depolymerized polyethylene terephthalate and liquefied wood polyesters can be used as a polyol for the production of polyurethane/polyisocyanurate foams. In this research, liquefied wood was synthesized by using a combination of diethylene glycol and glycerol and due to the possibility of using glycerol that is a by-product in biodiesel production, our goal was to use as much glycerol in the liquefaction reagent as possible. We determined the properties of the polyols, properties of produced foams, and explained their correlation. Greater amount of glycerol in the liquefaction reagent resulted in higher OH number, molecular weight, functionality, and viscosity of the polyol, as well as in longer cream time and tack free time in foam preparation. Glass transition temperature, density, and water absorption of the foam increased with increasing amount of glycerol in liquefied wood. Compressive stress increased up to 30% of the glycerol in the reagent and then reduced, while thermal conductivity was not affected. V
Polymers
Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. The effect of the NCO index on the physical, chemical and compressive properties of the liquefied EFB-based PUF (EFBPUF) was evaluated. The EFBPUFs showed a unique set of properties at each NCO index. Foaming properties had affected the apparent density and cellular morphology of the EFBPUFs. Increasing NCO index had increased the crosslink density and dimensional stability of the EFBPUFs via formation of isocyanurates, which had also increased their thermal stability. Combination of both foaming properties and crosslink density of the EFBPUFs had influenced their respective compressive properties. The EFBPUF produced at the NCO index of 120 showed the optimum compressive strength and relea...
Polymers, 2020
Developing polyols derived from natural sources and recycling materials attracts great interest for use in replacing petroleum-based polyols in polyurethane production. In this study, rigid polyurethane (PUR) foams with various isocyanate indices were obtained from polyols based on rapeseed oil and polyethylene terephthalate (RO/PET). The various properties of the prepared PUR foams were investigated, and the effect of the isocyanate index was evaluated. The closed-cell content and water absorption were not impacted by the change of the isocyanate index. The most significant effect of increasing the isocyanate index was on the dimensional stability of the resulting foams. This is due to the increased crosslink density, as evidenced by the increased formation of isocyanurate and increase of the glass transition temperature. Additionally, the influence on compression strength, modulus, and long-term thermal conductivity were evaluated and compared with reference PUR foams from commerc...