Manufacture Of Polyurethanes Research Articles

1,5-Pentanediol production from 3,4-dihydro-2H-pyran and acetic acid via successive reactions of esterification and hydrogenation

1,5-Pentanediol as an important chemical intermediate is commonly used for the manufacture of polyesters and polyurethanes. A novel process was developed for the production of bio-based 1,5-pentanediol (1,5-PDO) from 3,4-dihydro-2H-pyran (DHP) and acetic acid (AA) in this work. The esterification of DHP and AA achieved a 59.8% DHP conversion and 91.2% tetrahydropyran-2-yl acetate selectivity (THPOAc) at 373 ​K for 1 ​h and DHP/AA molar ratio of 1 without catalyst. Then the 1,5-PDO with selectivity of 54.5% was obtained from THPOAc via hydrogenation over Cu/Zn8/Al catalyst under the conditions of 453 ​K and 50 ​bar. The higher dispersion of Cu nanoparticles, the larger surface area of metallic Cu, the higher amount of Cu+ active sites and the lower acidity of Cu/Zn8/Al catalyst were beneficial for the hydrogenation of THPOAc to 1,5-PDO.

Pembuatan Poliuretan Sebagai Bahan Pelapis Besi Dengan Pengisi Cangkang Kulit Telur

Research on the manufacture of polyurethane as an iron coating material with an eggshell filler has been done. The purpose of this study was to determine the effect of eggshell weight as an additive on the preparation of polyurethane as an iron coating material and to determine the weight effect of Methylene Diphenyl Diisocyanate (MDI) on the manufacture of polyurethane as an iron coating material with an eggshell filler. By mixing Jatropha oil polyols, Methylene Diphenylene Diisocyianate (MDI), and eggshell, then applied to an iron plate. Polyurethane coatings formed in the analysis of thermal adhesion properties of coatings, Thermal (TGA), functional groups (FT-IR), crystal structures (XRD), and coating morphology (SEM). The results obtained which in addition to the ratio of polyol: isocyanate: eggshell shell of 7: 3: 5% obtained the best results that have the strongest adhesion and has a good mixing structure, and has a heat resistance of 300 0C

Advances in lubricated polydimethylsiloxane surfaces for polyurethane foam molding

Adhesion problems are currently a challenge in the manufacture of molded polyurethane (PUR) foam products. Here, a novel solution has been proposed by infusing a polydimethylsiloxane (PDMS) matrix with a liquid lubricant to obtain slippery liquid-infused porous surfaces (SLIPS). These surfaces have been evaluated when PUR foam is molded on them. The level of adhesion, determined by tensile peel tests, helped to understand the relationship between adhesion phenomena, coating deformability and hysteresis contact angle. A wide variability of hydrophobicity and hardness was obtained among the tested samples. The percentage of oil infused and the way it is integrated into the coating matrix determine the coating performance. The adhesion strength has been significantly reduced thanks, on the one hand, to the lubricating layer generated from the infiltrated oil and, on the other hand, to a porous system capable of self-healing the altered SLIPS surface after demolding. An optimal balance between the elasticity and hydrophobicity of the surface has been obtained; the best surfaces with the least adherence and the greatest durability have been identified for obtaining the foam.

Valorization of palm oil via cross-metathesis reaction using 1-octene

The use of palm oil-derived polyol in polyurethane manufacturing is restricted owing to its poor hydroxyl value, which results in a suboptimal polyurethane network. Palm oil could be first chemically modified by cross metathesis (CM) into olefin and ester products with terminal double bonds prior to converting it to the polyols with optimum hydroxyl value. Due to the catalyst degradation and the unwanted self-metathesis reaction, the plant oil CM employing ethylene has been limited by its poor selectivity and low yield. The goal of present research is to investigate the palm oil CM using 1-octene from the aspects of parametric and kinetic analysis. The use of 1-octene was hypothesized to prevent the formation of undesired catalytic intermediates and hence allowing the ruthenium-based Hoveyda Grubbs second generation catalyst (2nd HGC) to maintain its activity and stability. Adopting one factorial at time (OFAT) in a batch system, the effect of different parameters on cross-metathesis of palm oil was examined. The variation in reaction time, temperature, reactant molar ratio of 1-octene to triolein (MOC/TR), and catalyst loadings were correlated to triolein conversion, yield, and selectivity of 1-decene. The products such as 1-decene and glyceryl tri-9-decenoate were quantified using Gas Chromatography-Mass Spectrometry (GC-MS). The maximum triolein conversion and 1-decene yield, 97.78% and 293.36% respectively, were obtained when the cross metathesis of palm oil using 1-octene occurred at 343 K for 2 h with MOC/TR of 8 and catalyst loading of 5 ppm. After three consecutive catalytic tests carried out at best operating condition, the insignificant decline in the reaction performance evidenced that the 2nd HGC catalyst remained active and stable. It was also found that the power-law model well predicted the concentration profile of the cross-metathesis of palm oil using 1-octene, estimating activation energy of 22583 J/mol. This study developed a new technically feasible process for adding value to palm oil, by enabling the use of palm oil as a feedstock for the production of polyol.

Heterogeneously-catalyzed competitive hydroarylation/hydromination of norbornene with aniline in the presence of Aquivion® ionomer

The hydroarylation of alkenes with aniline is a reaction of high interest, in particular for the manufacture of polyurethanes. This reaction has been mostly investigated in the presence of homogeneous catalysts. So far, heterogeneous catalysts have been scarcely reported for this reaction, mainly due to their inherent low activity and deactivation during the course of the reaction. Here we report the catalytic performance of Aquivion® ionomer, a perfluorinated solid acid polymer, in the hydroarylation of norbornene with aniline. We show that Aquivion® ionomer was robust and can be recycled for at least 6 runs without any decrease of its catalytic performances. Our results also highlight that Aquivion® ionomer improves the propensity of aniline to react through its aromatic ring, thus yielding a higher proportion of hydroarylation products as compared to other tested homogeneous and heterogeneous catalysts.

Kinetic and stability study on the immobilized enzymatic step of one‐pot dimerization of 2‐[2‐(dimethylamino)ethoxy]ethanol

Tertiary amine catalysts (TACs) are essential organic molecules used in polyurethane manufacturing. Synthesis of these chemicals involves the use of catalytic transition metals at high temperatures and high pressures. Simple amine systems react easily with transition metals; however, amine systems with multiple hydroxyl groups and methylamine complexes produce significant byproducts. In this study, synthesis that forgo transition metals is explored. Enzymes can provide a clean industrial alternative to transition metal use. 2‐[2‐(dimethylamino)ethoxy]ethanol (DMAEE) is the monomer used in the synthesis of a model TAC. When DMAEE is first enzymatically oxidized, the aldehyde can serve as an electrophile for 2‐(methylamino)ethanol (MMEA), forming the DMAEE dimer. Choline oxidase catalysis is the first step of this pathway. Steady state kinetic parameters of choline oxidase with choline and DMAEE as substrates, optimum pH, and temperature stability are reported in this study. The effect of MMEA on the enzymatic reaction is examined as well. In an industrial application, immobilized enzymes can enhance stability over a broad range of temperature and pH. Therefore, choline oxidase was immobilized on CNBr‐activated Sepharose beads, and the effects of immobilization are reported in this study.

Absorption, distribution, metabolism, and excretion of methylene diphenyl diisocyanate and toluene diisocyanate: Many similarities and few differences.

Methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI) are high production volume chemicals used for the manufacture of polyurethanes. For both substances, the most relevant adverse health effects after overexposure in the workplace are isocyanate-induced asthma, lung function decrement and, to a much lesser extent, skin effects. Over the last two decades many articles have addressed the reactivity of MDI and TDI in biological media and the associated biochemistry, which increased the understanding of their biochemical and physiological behavior. In this review, these new insights with respect to similarities and differences concerning the adsorption, distribution, metabolism, and excretion (ADME) of these two diisocyanates and the implications on their toxicities are summarized. Both TDI and MDI show very similar behavior in reactivity to biological macromolecules, distribution, metabolism, and excretion. Evidence suggests that the isocyanate (NCO) group is scavenged at the portal-of-entry and is not systemically available in unbound reactive form. This explains the lack of other than portal-of-entry toxicity observed in repeated-dose inhalation tests.

Straightforward Synthesis of Amido Polyols from Epoxidized Soybean Oil for Polyurethane Films

AbstractThis work reports a straightforward and selective method for the preparation of a polyol that can be used in the manufacture of polyurethane (PU) films. The polyol, from the N‐hydroxyalkylamides family, is obtained from the selective amidation and oxirane ring opening of epoxidized soybean oil (ESO) with the amino alcohol N‐methylethanolamine (N‐MEA). The reaction is carried out under mild conditions and in the absence of solvents and catalysts. Other similar amino alcohols (namely monoethanolamine (ETA), 5‐amino‐1‐pentanol (PEA), and 2‐(2‐aminoethoxy)ethanol (AEE)) are also used to carried out the amidation of ESO. However, for these amines, the amidation and/or oxirane ring opening of ESO is not complete. Therefore, the N‐hydroxyalkylamide obtained from the amidation of ESO with N‐MEA is chosen as the polyol for the preparation of PU films. The PU films are obtained from the reaction with a trimer of hexamethylene diisocyanate (Tolonate) and hexamethylene diisocyanate (HDI). Curing proceeds at room temperature, without catalyst. It is shown that the properties of the resulting PU films are dependent on the amount of Tolonate in the formulation.

Occupational Exposure to Diisocyanates in the European Union.

ObjectivesDiisocyanates are a chemical group that are widely used at workplaces in many sectors. They are also potent skin- and respiratory sensitizers. Exposure to diisocyanates is a main cause of occupational asthma in the European Union. To reduce occupational exposure to diisocyanates and consequently the cases of diisocyanate-induced asthma, a restriction on diisocyanates was recently adopted under the REACH Regulation in the European Union.MethodsA comprehensive evaluation of the data on occupational exposure to the most important diisocyanates at workplaces was made and is reported here. The diisocyanates considered are methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and hexamethylene diisocyanate (HDI), accounting for more than 95% of the market volume in the EU. The exposure assessment is based on data from Chemical Safety Reports (CSRs) of REACH Registration Dossiers, workplace air monitoring data from Germany, from the UK Health and Safety Executive (HSE), and literature data relevant for the EU, and the USA.ResultsOccupational exposure to diisocyanates is particularly relevant in: (i) C.A.S.E. applications (Coatings, Adhesives, Sealants, Elastomers), (ii) production of polyurethanes (PUs) (e.g. slab-stock foam), (iii) handling of partly uncured PU products (e.g. cutting, demoulding, spray application of foam), and (iv) when diisocyanates/PUs are heated (e.g. hot lamination, foundry applications/casting forms). Ranking of the reported data on inhalation to diisocyanate exposure at workplaces (maximum values) leads to following order: (i) HDI and its oligomers in coatings, (ii) MDI in spray foam applications, (iii) TDI in manufacture of foam, (iv) TDI in manufacture of PUs and PU composite materials, (v) TDI in adhesives, (vi) MDI in adhesives, (vii) MDI in manufacture of PUs and PU composite materials, (viii) TDI in coatings, (ix) MDI in manufacture of foam, and (x) HDI in adhesives.

Synthesis and characterisation of polyurethane made from pyrolysis bio-oil of pine wood

This paper investigates the manufacture of polyurethane from pyrolysis bio-oil produced from radiata pine wood. Liquid-liquid extraction was used to separate bio-oil into fractions. These fractions were reacted with methylene diphenyl diisocyanate (MDI) to produce polyurethane. For comparison, a series of polyurethanes were prepared with castor oil in a similar manner. Among the various fractions of the bio-oil, the water-insoluble fraction (often referred to as pyrolytic lignin) was found to be the most appropriate component to produce polyurethane as it is a significant fraction of bio-oil and has a high hydroxyl number, hence, is able to produce a robust film. It was found that gradual addition of the polyol to MDI helped produce a more flexible and stable polyurethane film. Water absorption of bio-oil based polyurethane was found to be higher than that of castor oil based polyurethane. However, the diffusion coefficient of water in the bio-oil derived polyurethane was lower than in castor oil-derived polyurethane. These results suggest bio-oil derived polymers may be suitable for use as protective coatings.

Synthesis and characterization of chitosan-bentonite modified polyurethane with biomedical potential

Research on the manufacture of polyurethane with chitosan and bentonite fillers modified with CTAB into montmorillonite (MMT) which will be applied to medical devices. The raw polyurethane from castor oil and diisocyanate is in the form of Toluene Diisocyanate (TDI). The addition of chitosan to castor oil polyurethane functions as an anti-bacterial agent. Pure polyurethane still has a deficiency of high temperatures and therefore added MMT which functions as a heat-retaining agent. The bacteria used are E. coli bacteria and Staphylococcus Aureus bacteria. The results showed a polyurethane that can withstand high temperatures is PU-MMT-CS 6%. The best anti-bacterial properties were obtained in polyurethane containing chitosan with higher concentrations (PU-MMT-CS 6%)

Prediction of the content of NCO-groups in urethane prepolymers based on oligomeric diols with unidentified molecular weight

An effective and easy to use method for estimating the molecular weight of starting oligomeric diols used for the synthesis of polyurethanes is developed. The prepolymers – linear oligomers with terminal isocyanate groups – are first synthesized as an intermediate product. To synthesize such prepolymers used in the free-casting manufacture of polyurethane and polyurethane urea compositions, oligodiol is reacted with an excess of diisocyanate, the ratio of NCO/OH groups being equal to or slightly higher than 2. This is very important for the second stage of synthesis when the prepolymer interacts with hardeners usually containing amine and hydroxyl groups. When the ratio NCO/OH  2 the resulting prepolymer contains a large amount of low molecular weight diisocyanate with a much higher activity compared to the repolymer. As a result, the potlife of polyurethane and polyurethane urea compositions can decrease to an nacceptable level. On the other hand, when the ratio NCO/OH < 2, the prepolymers with high molecular weight and relatively high viscosity can occur, which also complicates the processing of the aforementioned compositions. Maintaining the desired value of the ratio in the synthesis of prepolymers necessitates precise data on the molecular weight of the oligomeric diols used in the synthesis. Current methods for determining the molecular weight of oligomeric diols, based on the analysis of the content of hydroxyl groups have a number of disadvantages, namely the duration and complexity of the procedure and the high cost of the reagents. The developed method is based on conducting advanced syntheses of prepolymers with predetermined ratios between the initial oligomeric diols and diisocyanates. The equations linking the expected content of isocyanate groups in the prepolymer with the weight amounts of the starting components are derived. Testing of the method was carried out using ligoester and oligobutadiene isoprendiol as initial oligomeric diols.

Easy access to oxygenated block polymers via switchable catalysis

Oxygenated block polyols are versatile, potentially bio-based and/or degradable materials widely applied in the manufacture of coatings, resins, polyurethanes and other products. Typical preparations involve multistep syntheses and/or macroinitiator approaches. Here, a straightforward and well-controlled one-pot synthesis of ABA triblocks, namely poly(ether-b-ester-b-ether), and ABCBA pentablocks, of the form poly(ester-b-ether-b-ester’-b-ether-b-ester), using a commercial chromium catalyst system is described. The polymerization catalysis exploits mechanistic switches between anhydride/epoxide ring-opening copolymerization, epoxide ring-opening polymerization and lactone ring-opening polymerization without requiring any external stimuli. Testing a range of anhydrides, epoxides and chain-transfer agents reveals some of the requirements and guidelines for successful catalysis. Following these rules of switch catalysis with multiple monomer additions allows the preparation of multiblock polymers of the form (ABA)n up to 15 blocks. Overall, this switchable catalysis delivers polyols in a straightforward and highly controlled manner. As proof of potential for the materials, methods to post-functionalize and/or couple the polyols to make higher polymers are demonstrated.

Synthesis and Characterization Thermal of Polyurethane/MMT from Castor Oil Polyols for Coating

The purpose of this research overall is the manufacture of polyurethane nanocomposite from castor oil with the addition of montmorillonite nanoparticles as coating material. This study consists of several stages, the manufacture of montmorillonite nanoparticles (MMT), the process of forming polyols from castor oil by epoxidation and hydroxylation reactions with catalysts. The manufacture of polyurethanes (PU) by reacting polyols from castor oil and organic montmorillonite nanoparticles was then characterized and applied to polyurethane nanocomposites as coating materials. Organic montmorillonite nanoparticles are made by an intercalation process with cetyl trimetyl ammonium bromide (CTAB). Polyurethane nanocomposite was prepared by adding organic montmorillonite nanoparticles in polyols before being mixed with toluene diisocyanate. The effectiveness of polyurethane nanocomposites as heat-resistant coatings was determined by thermal properties with thermo gravimetric analysis (TGA) equipment, then the adhesive strength was tested and the morphological properties of the material coating. The manufacture of polyurethane nanocomposite from castor oil as a film coating is applied to material and characterization.

Carbon2Polymer – Conceptual Design of a CO2‐Based Process for the Production of Isocyanates

AbstractThe capture of carbon dioxide and its utilization as a building block in chemical synthesis aim at reducing the depletion of fossil resources and the emission of greenhouse gases. The project Carbon2Chem®‐L5 is dedicated to the development of processes using CO2 for the production of polymer building blocks for polyurethanes. In this work, a process concept is presented for the CO2‐based synthesis of diisocyanates, the main starting material in polyurethane manufacture. Key parameters for process performance are discussed.

National Chemical Technician Award to Jay Allen

Jay Allen, a senior analytical technologist for propylene oxide and propylene glycol at Dow Chemical, is the winner of the 2017 National Chemical Technician Award. The award, administered by the Committee on Technician Affairs, honors excellence and professionalism among technicians, operators, analysts, and other applied chemical technology professionals. During his 30-plus-year career at Dow, Allen has developed and improved numerous analytical methodologies and technologies used for the development and manufacture of polyurethanes, polymers, and high-performance plastic materials. As manager of the site’s propylene oxide and propylene glycol laboratories, he has taken a leadership role in improving the general safety of the lab work environment. Allen has served as the Site Analytical Leadership Team steering team leader for 10 years. Allen was presented with a plaque recognizing his award during the Division of Chemical Technicians luncheon at the ACS national meeting in San Francisco in early April.

Study of Sound Absorption Properties on Rigid Polyurethane Foams using FEA

Objective: The range of raw material used for the manufacture of Polyurethane using Polyol has grown enormously during the past fifty years. A wide range of products is now available, which allows the researchers to produce, collectively known as Polyurethane Foams as Porous Material. This paper examines the sound absorption properties of porous material from the view point of the manufacturer by the experimental and analysis way. Method/Analysis: In this experimental study, finite element method is well established in estimating acoustic transmission loss or sound absorption coefficient of a porous material. Impedance tube is used to measure the acoustic impedance of a sound absorbing porous material, with acoustic source at one end and an acoustic porous material. That is polyurethane foam at other end. There are two common methods used to measure the impedance value of the porous material. The first method involves a moveable microphone that transverses along the impedance tube and the second method is named as “transfer function” or “two-microphone”, the two microphone method is followed in this section. In this study, a 3D impedance tube is modelled using finite element software and the results will be compared with experimental data. Finding: The effort for this study determines a straight forward route to the production of Rigid Polyurethane foams through a direct reaction process. This system has potentially wide relevance as polyurethane foams. Here, an initial study has shown that using different way to calculate the sound absorption coefficient of a material, either by experimental way or by analysis using FEA software ansys. Application/ Improvement: Besides much other application, rigid polyurethane foam is used as acoustic layer in automobile industries, thermal insulation and as energy absorber medium in front bumper of auto motives. Hence by comparing the sound absorption coefficient value of the foam by the both experimental and analysis method we can improve the understanding level and efficiency of the rigid polyurethane foam.

Biopolyols obtained via crude glycerol-based liquefaction of cellulose: their structural, rheological and thermal characterization

In this work lignocellulose biomass liquefaction was used to produce biopolyols suitable for the manufacturing of rigid polyurethane foams. In order to better evaluate the mechanism of the process, pure cellulose was applied as a raw material. The effect of time and temperature on the effectiveness of liquefaction and the parameters of resulting biopolyols were characterized. The prepared materials were analyzed in terms of their chemical structure, rheology, thermal and oxidative stability, and basic physical and mechanical properties that are important from the point of view of polyurethane manufacturing. The optimal parameters for the biopolyol production with a 94 % yield were achieved at 150 °C for a 6-h reaction duration. The obtained polyols were characterized by the hydroxyl number of 643 mg KOH/g and enhanced thermal and oxidative stability compared to the polyols obtained at lower temperatures, which is associated with the altered mechanism of liquefaction. The results of rheological tests, analyzed with the use of Ostwald-de Waele and Herschel Bulkley models, revealed that the prepared biopolyols can be classified as pseudoplastic fluids with the viscosity values similar to those of commercially available products. Rigid foams obtained via partial substitution of petrochemical polyol with prepared bio-based one were characterized by slightly increased apparent density and average cell size comparing to unmodified materials. The best mechanical performance was observed for the sample containing 35 wt% of biopolyol in the polyol mixture, which indicates a synergistic effect between the applied polyols. The applied modification delayed thermal degradation of foams due to changes in thermal decomposition process. In conclusion, the presented work confirms that lignocellulose biomass liquefaction can be successfully applied as a manufacturing method of polyols later used in the production of polyurethanes.

Preparation and characterization of polyurethane plasticizer for flexible packaging applications: Natural oils affirmed access

Developing bio-renewable feedstock for polyurethane (PU) manufacturing and polymer industry as a whole has become highly desirable for both economic and environmental reasons. In this work castor oil (CO) and palm olein (PO) polyols were synthesized and partially used as renewable feedstock for the manufacturing of polyurethane plasticizing resin for printing ink applications. The chemical structure of the prepared polyols and polyurethanes were characterized using IR spectra and GPC and their solubility in common solvents was tested. As well, properties such as flexibility, mechanical properties, optical properties, heat seal and freeze resistance of these prepared printing inks were determined. The results indicated that the prepared printing inks from 50% synthesized polyurethane have high thermal stability, adhesion and excellent freeze resistance. The net technical properties of the new ink formulations are relatively comparable to the printing ink prepared from standard polyurethane plasticizer.

Sustainable Polyurethane Adhesives Derived from Carbon Dioxide

The demand for fuels as raw materials is increasing disproportionally, thus producing huge environmental impacts, as is the case of carbon dioxide emissions into the atmosphere. Nowadays, society is facing several challenges, including the implementation of new technologies that are able to meet energy needs and promote sustainable development. Therefore, one of the most commonly produced and used polymers worldwide, polyurethane, which is currently completely dependent on fossil fuels, could be developed in an environmentally sustainable way. In this regard, CO2 may be used for the synthesis of new materials, such as for the production of polyols, essential components in the manufacture of polyurethane. This work focused on the synthesis of polyurethane adhesives containing polyols from CO2. They were synthesised with 4,4'-diphenylmethane diisocyanate (MDI) and 1,4-butanediol as a chain extender. The sustainable polyurethane adhesives derived from carbon dioxide were characterised by Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric tests (TGA). Finally, the adhesion properties were measured from a T-peel test on leather/polyurethane adhesive/ SBR rubber joints, in order to establish the amount of CO2-based polyol that could be added to polyurethane adhesives satisfactorily to meet the quality requirements of footwear joints.