Polyurethane Thermosets Using Lipidic Poly(α‐Hydroxyketone) (original) (raw)
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Polymer
The sustainability of the polymeric materials has become a fundamental challenge; therefore, the development of new biobased formulations has gained increasing interest. Thermoset polyurethanes (PURs) present high performance and are a competitive solution for structural composites. However, polyols used in the PUR synthesis are typically from petrochemical origin. Nowdays, a broad range of biobased polyols is available in the market, but there is not yet a specific formulation for high performance PURs composites. The aim of this work was to study the effect of biobased polyols' characteristics in the PUR processing and final properties. In addition, biobased polyol features to synthesize BIO-PURs suitable for structural applications were stablished. The viscosity and reactivity were studied by means of rheology and differential scanning calorimetry (DSC). Thermal and mechanical properties were studied through thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and flexural tests. The results obtained demonstrated the dramatic influence of polyols' nature on BIO-PUR/PUR properties and their effect on the crosslink density. It was observed that using a high functionality and high hydroxyl index biobased polyol, it was possible to synthesize high performance BIO-PUR suitable for structural composites.
Journal of Oleo Science, 2013
INTRODUCTION Polyurethane is a versatile polymer which had been found an increasingly outstanding position among the most important organic polymers in coating industries, elastomeric items, and materials for engineering, biomaterials in implants, electronic and technological applications as their structure can be tailor-made to suit specific requirements due to the vast variety of raw materials available of polyols and isocyanates 1 4. Thermoplastic polyurethane is a linear segmented block copolymer composed of hard and soft segments that can be deformed plastically under the influence of heat and returns to solid when cooled. On the other hand, thermosetting polyurethane which is highly cross-linked polymer behaves differently as they cannot be melted after curing process. Both thermoplastic and thermosetting polyurethanes are usually consumed petroleum as their raw material in products such as coated fabrics, wire coatings, shoe
The physical and mechanical properties of polyurethanes from oleic acid polyols
Journal of Applied Polymer Science, 2009
Three different polyester polyols, with various oleic acid content, were used in the preparation of polyurethane (PUR) coatings. The polyols were designated as Alk28, Alk40, and Alk65, in which 28, 40, and 65 represent the percentage of oleic acid of the polyol formulations. These polyester polyols were reacted with aromatic diisocyanate [toluene diisocyanate (TDI)] to form PUR coatings. The acid value, hydroxyl value, molecular weight, and viscosity of the polyols have been determined. The reaction between the polyols and TDI was studied by Fourier Transform Infrared spectroscopy and X-ray diffraction (XRD). The effects of varying NCO/OH ratio and oleic acid content of polyols on physical and mechanical properties of PUR films were studied. XRD results indicate that the samples are amorphous. PURs, made with Alk28, have the best mechanical properties followed by Alk40 and Alk65. The mechanical properties of the samples have increased as the NCO/OH ratio was increased from 1.2 to 1.6. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Fully Bio-Based Thermosetting Polyurethanes from Bio-Based Polyols and Isocyanates
Polymers
The trend towards the utilization of bioresources for the manufacturing of polymers has led industry players to bring to the market new monomers. In this work, we studied 3 polyisocyanates and 2 polyols with high renewable carbon contents, namely L-lysine ethyl ester diisocyanate (LDI), pentamethylene-diisocyanate (PDI) isocyanurate trimer, and hexamethylene-diisocyanate (HDI) allophanate as the isocyanates, as well as castor oil and polypropanediol as the polyols. These monomers are commercially available at a large scale and were used in direct formulations or used as prepolymers. Thermosetting polymers with Tg values ranging from −41 to +21 °C and thermal stabilities of up to 300 °C were obtained, and the polymerization was studied using NMR, DSC, and rheology. Cured materials were also characterized using FTIR, DMA, gel content, and swelling index determinations. These high bio-based content materials can successfully be obtained and could be used as alternatives to petro-based ...
Polymer, 2005
New telechelic cis-1,4-polyisoprene oligomers bearing an hydroxyl group at the end of the polyisoprene backbone and possessing controlled molecular weights were used as soft segments in the elaboration of polyurethane elastomers. Besides, the well defined hydroxytelechelic cis-1,4-polyisoprene (HTPI) structure obtained through a controlled methodology, was chemically modified leading to hydrogenated and epoxidized oligomers based polyurethanes. The influence of the structural changes of these precursors on the polyurethanes properties have been studied. Thus, mechanical parameters as well as glass transition and mechanical transition temperature measurements indicated an increase in PUs hardness when the length of soft segment decreases and when the degree of epoxidized and hydrogenated isoprenic moieties increases. Moreover, based on thermogravimetric analysis (TGA), a linear relationship was established between the weight loss in the urethane stage degradation and the amount of hard segments in the PUs. Otherwise, the hydrogenated soft segments were found more thermally stable than the epoxidized and the non modified ones. By comparison with similar investigations developed from commercial oligodienes (PBHT R20 LM w and EPOL w ), this study mainly showed that the PUs based on hydrogenated hydroxytelechelic cis-1,4-polyisoprenes were more thermally stable and softer than the EPOL w based analogues. q Polymer 46 www.elsevier.com/locate/polymer 0032-3861/$ -see front matter q
Polymer Degradation and Stability, 2012
Biobased thermoplastic polyurethanes (TPUs) obtained from dimer acid-based polyols, 4,4 0 -diphenylmethane diisocyanate and 1,4-butanediol were synthesised by using a two-step prepolymer process. The effect of dimer acid-based polyols on the processing parameters was investigated. A full thermal, mechanical and thermo-mechanical characterisation of TPUs synthesised with different hard segment (HS) contents was also carried out. Thermogravimetric analysis showed the presence of three degradation steps which varied between the different TPU structures depending on the HS content. Colour tests showed substantial differences between TPU samples which were related to degradation parameters. Initial degradation temperatures were lower than the polyol's one and decreased with increasing HS contents. Tensile tests showed high deformation at break for these elastomeric TPU samples, except for the sample with 40 wt% of HS. Finally, rheology studies revealed that the melting temperature generally decreased with higher HS contents.
European Journal of Chemistry, 2018
Thermo-responsive vegetable oil-based polyurethanes were successfully prepared by poly-condensation reaction in the mixture of polyol and hexamethylene diisocynate. The functionality and high molecular weight of the polyurethanes were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR), Carbon Nuclear Resonance Spectroscopy (13C NMR), and Gel Permeation Chromatography. The viscosity of the polyols was characterized by Rheometry and flow rate of the polyols were derived from power law model. The kinetic and thermodynamic parameters of synthesized polyurethanes HSCP and HPCP were calculated from by TG curve. Five different mass loss temperature was obtained in the TGA curve of HSCP and HPCP, which corresponded to the decomposition of the physically observed NH and C=O formed between polyol and diisocyanate, respectively. The average value of the activation energy calculated by Murray and White, Coats and Redfern, Doy...
A green approach toward oleic- and undecylenic acid-derived polyurethanes
Journal of Polymer Science Part A: Polymer Chemistry, 2011
Naturally occurring oleic and undecylenic acids were used as raw materials for the synthesis of novel polyurethanes (PUs). The application of environmentally friendly thiol-ene additions to 10-undecenoate and oleate derivatives was studied with the goal of obtaining renewable diols. The resulting monomers were then polymerized with 4,4 0-methylenebis (phenylisocyanate), in N,N-dimethylformamide solution using tin (II) 2-ethylhexanoate as catalyst, to produce the corresponding thermoplastic PUs (TPUs). Also, ultrasound irradiation has been tested to improve the synthesis of PU. Under these conditions, TPUs were obtained in high yields (80-99%) with weight-average molecular weights in the 36-83 kDa range. The chemical structures of PUs were assessed by FTIR and NMR spectroscopy. The thermal and mechanical properties of the synthesized TPUs have been studied and they showed a clear dependence on the structure of the parent diol. MTT test was carried out to asses the potential cytotoxicity of the prepared PUs, indicating no cytotoxic response. V
Lipidic polyols using thiol‐ene/yne strategy for crosslinked polyurethanes
Journal of Polymer Science Part A: Polymer Chemistry, 2014
Oleic acid and diacid were converted into propargylic esters followed by thiol-ene/yne coupling (TEC/TYC) functionalizationin presence of mercaptoethanol. The multi-radical addition on fatty esters leads to the formation of lipidic polyols (OH1 and OH2), as judged by 1 H NMR and mass spectroscopiesas well as by steric exclusion chromatography (SEC). The crosslinking reaction between TEC/TYC-based polyols and MDI isocyanate reactant was monitored by FTIR experiment and reaction parameters were optimized. By differential scanning calorimetry (DSC), relatively high glass transitions are measured corresponding to structure with little or without dangling chain. Moreover, the thermal stability of the resulting plant oil-based polyurethane materials (PU1 and PU2)were found to be fully consistent with that of other lipidic polyurethanes respectinga three-step process.Thanks to TYC methodology, fatty diacid produces lipidic polyol without dangling chain and lipidic thermoset PU with relatively high Tg.
Polymer, 2012
Four aliphatic thermoplastic poly(ester-urethane)s (PEUs) with similar molecular weights but varying polyesters molecular weight (534e1488 g/mol) were prepared from polyester diols, obtained by melt condensation of Azelaic acid and 1,9-Nonanediol, and 1,7-heptamethylene di-isocyanate (HPMDI) all sourced from vegetable oil feedstock. The thermal, and mechanical properties, and crystal structure of PEUs were investigated using DSC, TGA, DMA, tensile analysis and WAXD. For sufficiently long polyester chain, WAXD data indicated no hydrogen bonds polyethylene (PE)-like crystalline packing and for short polyester chains, small crystal domains with significant H-bonded polyamide (PA)-like packing. Crystallinity decreased with decreasing polyester molecular weights. The polymorphism of PEUs and consequently their melting characteristics were found to be largely controlled by polyester segment length. TGA of the PEUs indicated improved thermal stability with decreasing polyester chain length, suggesting a stabilization effect by urethane groups. Mechanical properties investigated by DMA and tensile analysis were found to scale predictably with the overall crystallinity of PEUs.