Polyol Research Articles

Organic carbonates as green and sustainable complexing agents for double metal cyanide catalysts for the synthesis of polyether and poly(ether-carbonate) polyols

We investigated various linear carbonates, including dimethyl carbonate and diethyl carbonate, and cyclic carbonates such as ethylene carbonate, propylene carbonate (PC), butylene carbonate, and glycerol carbonate, as complexing agents (CAs) for the preparation of double metal cyanide (DMC) catalysts. The DMC catalysts bearing carbonate complexing agents exhibited good to excellent activities for the ring-opening polymerization of epoxides (turnover frequencies of up to 467 min−1) and the copolymerization of epoxides and CO2, producing polyether polyols with moderate molecular weights (1700–9700 g mol−1), narrow polydispersity indexes (1.1–1.2), very low unsaturation values (0.002–0.009), and low viscosities (438 −997 cP). The DMC catalyst bearing PC also afforded linear and branched polycarbonate polyols in high yields (up to 83%) and carbonate contents (up to 36 mol%). Density functional theory calculations were also performed to understand the effect of the CAs on the structural properties and activities of the corresponding DMC catalysts.

Microstructure characterization and mechanistic insight into polyether polyols and their associated polyurethanes.

This article reviews the analytical tool chest used for characterizing alkoxylates and their associated copolymer mixtures. Specific emphasis will be placed upon the use of mass spectrometry-based techniques as rapid characterization tools for optimizing reaction processes in an industrial R&D setting. An initial tutorial will cover the use of matrix-assisted laser desorption/ionization-mass spectrometry and tandem mass spectrometry fragmentation for detailed component analysis (e.g., polyol and isocyanate) of a model polyurethane-based foam. Next, this critical feedback information will be used with the guidance of mass spectrometry to initiate the development of a new, more efficient, tris(pentafluorophenyl)borane (FAB) catalyst-based alkoxylation process for generating the next generation of glycerin-initiated poly(propylene oxide)-co-poly(ethylene oxide)copolymers. Examples will be provided for each step in the FAB-based optimization process that were required to generate the final product. Following this example, two-dimensional liquid chromatography, supercritical fluid chromatography, and ion mobility separations, along with their coupling to mass spectrometry, will be reviewed for their efficiency in characterizing and quantitating the components within these complex polyether polyol mixtures.

Recycling and Reuse Production Technology of Waste Polyurethane Foam

Waste polyurethane foam is a kind of manufacturing and construction industry waste used as raw material to produce polyol polymer with high added value. In this way, the recycling economy of waste polyurethane foam is developed. In this paper, a production process line for recycling waste polyurethane foam was designed and established. The economic benefits of the production line were evaluated with the production cost as the index and the actual production data. Compared with the price of commercial polyether polyol, the price of regenerated polyether polyol was 13, 920 CNY/t, which was reduced by 30.4%. The re-foaming of the regenerated polyether polyol was observed by scanning electron microscope. The results showed that the polyurethane foam foamed with regenerated polyether polyol had a complete bubble structure. The bubble structure is regular and completely hexagonal, with a strong skeleton, an excellent cross-linking structure, and a uniform and dense bubble distribution. Therefore, the production process can be widely promoted as a sustainable, green, and high-value-added waste polyurethane treatment process.

A Hyperbranched Polyol Process for Designing and Manufacturing Nontoxic Cobalt Nanocomposite.

A method for the design and synthesis of a metallopolymer composite (CoNP) based on cobalt nanoparticles using the hyperbranched polyol process was developed. It was shown that hyperbranched polyester polyols in a melted state can be both a reducing agent and a stabilizer of metal nanoparticles at the same time. The mechanism of oxidation of hyperbranched polyol was studied using diffuse reflectance IR spectroscopy. The process of oxidation of OH groups in G4-OH started from 90 °C and finished with the oxidation of aldehyde groups. The composition and properties of nanomaterials were determined with FT-IR and UV-Vis spectroscopy, Nanoparticle Tracking Analysis (NTA), thermogravimetric analysis (TG), powder X-ray diffraction (XRD), NMR relaxation, and in vitro biological tests. The cobalt-containing nanocomposite (CoNP) had a high colloidal stability and contained spheroid polymer aggregates with a diameter of 35-50 nm with immobilized cobalt nanoparticles of 5-7 nm. The values of R2 and R1 according to the NMR relaxation method for CoNPs were 6.77 mM·ms-1 × 10-5 and 4.14 mM·ms-1 × 10-5 for, respectively. The ratio R2/R1 = 0.61 defines the cobalt-containing nanocomposite as a T1 contrast agent. The synthesized CoNPs were nonhemotoxic (HC50 > 8 g/mL) multifunctional reagents and exhibited the properties of synthetic modulators of the enzymatic activity of chymosin aspartic proteinase and exhibited antimycotic activity against Aspergillus fumigatus. The results of the study show the unique prospects of the developed two-component method of the hyperbranched polyol process for the creation of colloidal multifunctional metal-polymer nanocomposites for theranostics.

In situ Monitoring of Double Metal Cyanide (DMC) Catalyst Synthesis by Raman Spectroscopy

Double metal cyanide (DMC) catalyst is widely used for the alkoxylation reaction to produce polyether polyol from ethylene/propylene/butylene oxides. It is challenging to optimize the synthesis process, due to the lack of real-time understanding of the speciation of the reaction mixture. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and actual alkoxylation reaction performance are effective ways for the evaluation of success of each synthesis, but it is difficult to guide process optimization. An in situ Raman method is developed in this study to monitor the DMC catalyst synthesis in real time to accelerate the process optimization. The synthesis involves the reaction of ZnCl2 and K3Co(CN)6 (KHCC) to form Zn3[Co(CN)6]2 (ZHCC). ZHCC is then converted to DMC in the presence of excess of t-butanol and ZnCl2 in the second step. Characteristic KHCC Raman peaks were observed at 2138 and 2153 cm-1, ZHCC at 2185 and 2206 cm-1, and DMC at 2203 and 2225 cm-1, respectively. This enables realtime tracking of both steps’ conversion. Both t-butanol and ZnCl2 concentrations were found to substantially influence the kinetics of DMC formation, but not the Raman spectra of the final DMC products. The reaction time could be adjusted from hours to minutes through the control of reactant concentrations.

Synthesis and properties of UV‐curable star‐shaped polyester

AbstractUV‐curable coatings mainly include vinyl resin, active thinner, and photoinitiator, among which UV‐curable resin accounts for a large proportion and is the main factor that determines the film performance. Existing vinyl resins have the disadvantages of high viscosity, high cost, and low curable function. Herein, the polyol as the core, first reacted with anhydride to produce half ester, and then with glycolyl methacrylate ring opening to get vinyl star polyester. The molecular structure and molecular weight of UV‐curable star polyesters were analyzed using FTIR, 1H NMR, and GPC. The impact of the type and ratio of anhydride and small molecular polyols on the viscosity and coating properties of vinyl star polyester were investigated. The results indicated that the resin viscosity and film hardness increased as the hydroxyl function of small molecular polyols increased. It was also discovered that the inclusion of polyether polyol N210 in the reaction system reduced the viscosity of the resin to 2025 mPa s and improved the hardness of the film to 2H, as well as its impact toughness.

Polyurethane foams co-blown by water and alkylated polyethylenimine-CO2 adducts: An additive or antagonistic effect?

Recently developed CO2 adducts of alkylated polyethylenimines (PEIs) can replace traditional, ozone-depleting, and/or global warming halogen-containing blowing agents of polyurethanes (PUs). Meanwhile, water is the most common chemical blowing agent that is cheap and also environment neutral. Herein, the co-blowing performances of the two types of blowing agents were investigated. For the polyether polyol or castor oil derived polyol foaming systems, which were blended just before foaming, the consequent co-blown foams surprisingly did not possess lower densities than the control foams blown solely by water, showing an antagonistic effect in blowing performance. The relatively large particles (e.g. tens of micrometers) of the hydrophilic PEI-CO2 blowing agents absorbed water from the foaming mixtures, preventing the trapped water from chemically blowing PUs. After the foams were set, the absorbed water gradually diffused out to react with the residual isocyanate groups, which no longer contributed to PU foaming. Differently, after aging the castor oil derived polyol foaming mixtures (without water and isocyanate components that were added before PU foaming), the dispersed PEI-CO2 particles decreased in size down to nanoscale (about 20–180 nm). These nanoparticles were small enough for out-diffusion of the absorbed water, which generated foaming CO2 in time. The densities of the resultant foams could be lowered to the theoretical values. The additive effect with water could enhance the application freedom of the climate-friendly alkylated PEI-CO2 blowing agents.

Study on Efficient Degradation of Waste PU Foam.

In this paper, the high-efficiency degradation and alcoholysis recovery of waste polyurethane foam were realized using a combination of a high-efficiency alkali metal catalyst (CsOH) and two-component mixed alcoholysis agents (glycerol and butanediol) in different proportions, using recycled polyether polyol and one-step foaming to prepare regenerated thermosetting polyurethane hard foam. The foaming agent and catalyst were adjusted experimentally to prepare regenerated polyurethane foam, and a series of tests were conducted on the viscosity, GPC, hydroxyl value, infrared spectrum, foaming time, apparent density, compressive strength, and other properties of the degradation products of the regenerated thermosetting polyurethane rigid foam. The resulting data were analyzed, and the following conclusions were drawn: The optimal conditions of alcoholysis were obtained when the mass ratio of glycerol to butanediol was 3:2, the amount of cesium hydroxide was 0.08%, the reaction temperature was 170 °C, and the reaction time was 2.5 h. Regenerated polyurethane foam with an apparent density of 34.1 kg/m3 and a compressive strength of 0.301 MPa was prepared under these conditions. It had good thermal stability, complete sample pores, and a strong skeleton. At this time, these are the best reaction conditions for the alcoholysis of waste polyurethane foam, and the regenerated polyurethane foam meets various national standards.

The Effect of NCO Content in Polyurethane Foam for Automotive Instrument Panel

A thermoplastic polyurethane (TPU) series for automotive panels with high durability have been newly synthesized using the reacting process based on polyester polyol (BTG), polycaprolactone triol (PCL), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 1,4-butanediol chain extender as a function of NCO/OH ratio (NCO index). The dependence of varying NCO index of synthesized TPUs on tensile strength and hardness have evaluated. To form PU foams with suitable rigidity and uniform skin-pores, the optimal synthetic process was controlled precisely by the amount of solvent, foaming agent, silicone surfactant, and catalysts content. A considerable NCO index dependence was observed in the range of 0.96 ≤ NCO index ≤ 0.99 at almost same molecular weight. When NCO index of TPU was 0.98, mechanical properties achieved maximum value due to the uniform open cell structure of molding PU foam. With the ratio of NCO/OH increasing, the hardness of PU foam also increased until 0.98 NCO index while the hardness of 0.99 NCO index decreased. The designed TPU with 0.98 NCO could be a promising formulation for molding foams of automotive skin panels and seating.

Preparation and performance study of modified soybean oil polyurethane foam used for soccer equipment

AbstractSoccer is known as the world's largest sport and has a wide range of players. Most of the materials used in existing football equipment are polyurethane extracted from petrochemical resources, which are gradually reduced and non‐renewable. Finding an alternative new material is an inevitable trend. Soybean oil (SO) was quantitatively transformed into polyols to afford industrially important high resilience flexible polyurethane foam(HR‐PUF). Photoinduced thiol‐ene click chemistry was investigated for the efficient preparation of modified soybean oil polyols (MESO) with primary hydroxyl groups. In order to improve the reaction efficiency and the degree of carbon–carbon double bonds functionalization, reduce reaction time, we have chosen a step‐by‐step method of adding. The effects of different reaction times and [thiol]/[ene] ratios on conversion and degree of functionalization were discussed. It is realized that under room temperature conditions, after 12 h of reaction, the carbon–carbon double bond of SO is almost completely converted and quantitatively converted into a hydroxyl group to a degree of 89%. The corresponding HR‐PUFs were prepared by mixing MESO with L2000 (Polyether Polyol). The effect of the difference in the amount of MESO added to the foam properties was investigated. Through the apparent density and a scanning electron microscope (SEM), it can be concluded that with the amount of MESO added increases, the cell size, opening ratio and the number of cells of HR‐PUF are decreased, the density is increased. Through thermogravimetric analysis (TGA) and dynamic thermomechanical analysis (DMA), it was proved that the thermal stability of the foam increased with the addition of MESO. Through 40% compression strength (CLD40%), ball rebound experiments, and static compression experiment. It is proved that the increase of the addition of MESO, the rebound resilience of HR‐PUF can be improved.

Big Data in The Preparation and Application of Phosphorus and Nitrogen Synergistic Flame-Retardant Polyester Polyols: Based on IoT Monitoring

Big Data in The Preparation and Application of Phosphorus and Nitrogen Synergistic Flame-Retardant Polyester Polyols: Based on IoT Monitoring

A Review of Waterborne Polyurethane Coatings and Adhesives with Polyester Polyol from Poly(Ethylene Terephthalate) Waste

A Review of Waterborne Polyurethane Coatings and Adhesives with Polyester Polyol from Poly(Ethylene Terephthalate) Waste

Determination of End-Group Functionality of Propylene Oxide-Based Polyether Polyols Recovered from Polyurethane Foams by Chemical Recycling.

Chemical recycling of polyurethane foams (PUFs) leads to partially aromatic, amino-functionalized polyol chains when the urethane groups in the PUF structure are incompletely degraded. Since the reactivity of amino and hydroxyl groups with isocyanate groups is significantly different, information on the type of the end-group functionality of recycled polyols is important to adjust the catalyst system accordingly to produce PUFs from recycled polyols of suitable quality. Therefore, we present here a liquid adsorption chromatography (LAC) method using a SHARC 1 column that separates polyol chains according to their end-group functionality based on their ability to form hydrogen bonds with the stationary phase. To correlate end-group functionality of recycled polyol with chain size, LAC was coupled with size-exclusion chromatography (SEC) to form a two-dimensional liquid chromatography system. For accurate identification of peaks in LAC chromatograms, the results were correlated with those obtained by characterization of recycled polyols using nuclear magnetic resonance, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and SEC coupled with a multi-detection system. The developed method allows the quantification of fully hydroxyl-functionalized chains in recycled polyols using an evaporative light scattering detector and appropriate calibration curve.

Renewable triblock copolymers of polylactide and polyether polyol: degradation behaviors of their monolayers and films

Bio-based monomers appear to be more attractive and increasingly important due to their potential to reduce the environmental impact of traditional petrochemical-based polymer production. This study deals with the synthesis, characterization, and degradation of triblock copolymers containing polylactide (PLA) and bio-based polyether polyol. Although the glass transition and melting temperature of copolymers decrease with polyether polyol content, copolymerization of lactide with the polyether polyol shows slower enzymatic degradation behavior than PLA itself by using both Langmuir monolayers and thin films. Overall, controlling the degradation of biodegradable polymers is useful for the commodity industries because it provides a sustainable and customizable solution.

Thermogravimetric studies, kinetic modeling and product analysis of the pyrolysis of model polymers for technical polyurethane applications

The pyrolysis of four kinds of common polyurethanes comprising a rigid and a flexible foam, a cast elastomer, and a thermoplastic polyurethane (TPU) was investigated by thermogravimetric analysis and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). All samples are based on methylene diphenyl diisocyanate (MDI), with polyether polyols as the soft segment of the foams and polytetrahydrofuran as the soft segment of the cast elastomer and TPU. Each polyurethane degrades in a two-step manner with a high correlation between the polymer structure and the mass loss in each step. Two kinetic modeling approaches based on either parallel or consecutive reactions were successfully applied to describe the pyrolytic degradation. The virgin polymers and pyrolysis intermediates obtained from thermogravimetry with isothermal segments at different temperatures of 350–450 °C were investigated by ATR-FTIR. Both foams exhibit retention of feedstock nitrogen in a carbonaceous intermediate while no significant residue formation and nitrogen retention are observable for cast elastomer and TPU pyrolysis. Aromatic amines in the foam pyrolysis intermediates point to the formation of a secondary polymer originating from the urethane segments in the course of the degradation. In Py-GC/MS, the foams yield nitrogen-carrying fragments of the MDI. MDI and 1,4-butanediol are regenerated from TPU pyrolysis, indicating different degradation pathways. CE pyrolysis also releases 1,4-butanediol but no nitrogen-carrying compounds are detectable. This work demonstrates the individuality of polyurethane materials in terms of their pyrolysis behavior and released products. Potential high-value products are identified in pyrolysis at laboratory scale. The findings of this study underline the need for a comprehensive examination of polyurethane pyrolysis with differentiation of polyurethane composition and morphology to optimize technical scale polyurethane pyrolysis.

Development of an electrochemical membrane bioreactor for succinic acid production and in situ separation with engineered Yarrowia lipolytica cultivated on municipal biowaste hydrolysate

A novel electrochemical membrane bioreactor (EMB) integrating succinic acid (SA) production and in situ separation in the anode compartment through an anion exchange membrane was employed in fed-batch fermentations with Y. lipolytica PSA02004 using hydrolysates from the organic fraction of municipal solid waste (OFMSW) as feedstock. The initiation of electrolysis cell operation and the reduction of pH from 6 to 5.5 at 30 h in a 6.7 L bioreactor improved the SA production efficiency, resulting in 66.7 gSA/L, 0.51 g/g yield, 0.78 g/(L·h) productivity, high coulombic efficiency (66.2%) and relatively low electricity consumption for SA separation (2.6 kWh/kgSA). The recirculation of the fermentation broth in the cathode compartment and the OH– produced by water reduction reduced NaOH consumption (35.4%) for pH control during fermentation. The fermentation was efficiently replicated in a 30 L bioreactor with a low membrane surface area (100 cm2) electrolysis cell, but it failed with a higher membrane surface area (702 cm2) electrolysis cell indicating that yeast cell viability, cell design and EMB configuration are important aspects for process scale-up. SA crystals were purified, at 99.95% purity and 95% yield, from the anolyte solution via activated carbon treatment, evaporation, crystallization and drying. Cell removal via centrifugation and acidification stages were not required as in conventional SA purification processes. The produced SA crystals were suitable for the production of polyester polyols for polyurethane urea dispersions applications.

Preparation and optimization of WPU dispersion from polyether/polyester polyols for film and coating applications

BackgroundCastor oil and polytetramethylene ether glycol (PTMG) are used as polyester and polyether polyols. The waterborne polyurethane (WPU) resin is synthesized from polyether/polyester polyols following a ketone and catalyst-free pre-polymerization process. MethodsWPU resins are prepared from PTMG/castor oil with various hydroxyl molar ratios, such as 1/0, 3/1, 1/1, 1/3, and 0/1. Significant findingsThe results indicate that the WPU dispersions has a long shelf-life, high colloidal stability, and narrow distribution of molecular size. The addition of castor oil can increase the proportion of the cross-linking density, hard segments and hydrogen bonds of the WPU molecular chain. The addition of PTMG/castor oil increases from the molar ratio 1/0 to 1/1, the tensile strength of WPU film increases from 17.1 MPa to 25.6 MPa; the T5% increases from 250°C to 262°C; the water swelling ratio at 24 h decreases from 33.2 g/g to 19.4 g/g. The results indicate the using PTMG/castor oil can improve the mechanical strength, water resistance, and thermal stability of WPU film. The WPU could be applied to wood coatings with high properties. This study provides a cleaner process for optimizing the performance of WPU resin, which can replace conventional ketone- and organotin-based films and coatings.

Organonitriles as complexing agents for the double metal cyanide-catalyzed synthesis of polyether, polyester, and polycarbonate polyols

A series of double metal cyanide (DMC) catalysts prepared using nitrile compounds as complexing agents (CAs) was employed for the synthesis of polyether, polyester, and polycarbonate polyols. The DMC catalysts bearing nitrile CAs exhibited remarkably higher activities toward the ring-opening polymerization (ROP) of propylene oxide (PO) and ε-caprolactone (CL), as well as toward the copolymerization of PO with CO2, than conventional DMC catalysts prepared using tert-butyl alcohol as a CA. Accordingly, DMC catalysts bearing 2-methylbutyronitrile or isobutyronitrile showed the highest activities for the ROP of PO (TOF=533 min−1) and CL (TOF=83 h−1), respectively, whereas the DMC using acetonitrile CA exhibited the highest efficiency for the copolymerization of PO and CO2 (TOF=475 h−1). The resultant polypropylene oxide polyols were characterized by a narrow polydispersity index (1.1 −1.2) and a low unsaturation level (0.004−0.014). In addition, the DMC catalyst bearing isobutyronitrile afforded α,ω-hydroxyl-terminated polycaprolactones with controlled molecular weights (1000−9800 g mol−1) and a narrow polydispersity index of 1.1−1.5. Polycarbonate polyols with relatively high yields (56–67 %) and carbonate contents (30–38 %) were also obtained.

Study and Characterization of Regenerated Hard Foam Prepared by Polyol Hydrolysis of Waste Polyurethane.

In this paper, four different kinds of diols were used for the alcoholysis of waste thermoplastic polyurethane elastomers. The recycled polyether polyols were used to prepare regenerated thermosetting polyurethane rigid foam through one-step foaming. We used four different kinds of alcoholysis agents, according to different proportions of the complex, and we combined them with an alkali metal catalyst (KOH) to trigger the catalytic cleavage of the carbamate bonds in the waste polyurethane elastomers. The effects of the different types and different chain lengths of the alcoholysis agents on the degradation of the waste polyurethane elastomers and the preparation of regenerated polyurethane rigid foam were studied. Based on the viscosity, GPC, FT-IR, foaming time and compression strength, water absorption, TG, apparent density, and thermal conductivity of the recycled polyurethane foam, eight groups of optimal components were selected and discussed. The results showed that the viscosity of the recovered biodegradable materials was between 485 and 1200 mPa·s. The hard foam of the regenerated polyurethane was prepared using biodegradable materials instead of commercially available polyether polyols, and its compressive strength was between 0.131 and 0.176 MPa. The water absorption rate ranged from 0.7265 to 1.9923%. The apparent density of the foam was between 0.0303 and 0.0403 kg/m3. The thermal conductivity ranged from 0.0151 to 0.0202 W/(m·K). A large number of experimental results showed that the degradation of the waste polyurethane elastomers by the alcoholysis agents was successful. The thermoplastic polyurethane elastomers can not only be reconstructed, but they can also be degraded by alcoholysis to produce regenerated polyurethane rigid foam.

Research on main influencing factors and complete support technology for dynamic pressure and large deformation roadway

To determine the main factors influencing dynamic pressure and large deformation roadways, a targeted set of support technologies was designed. The 2603 air inlet roadway of the Zhangcun coal mine in Lu'an, Shanxi Province, was taken as an example. The influence of the Wenwangshan South normal fault and in situ stress field on the dynamic pressure roadway was analyzed theoretically, and the main factors influencing this dynamic pressure and large deformation roadway under natural geological conditions were determined. The effect of the existing roadway support scheme was evaluated by field test methods such as nondestructive bolt testing. The influence of mining two working faces on the dynamic pressure and large deformation roadway was studied by the FLAC3D numerical simulation method. On this basis, a new grouting material was developed, a complete set of technical schemes of full-section integrated cooperative support of dynamic pressure and large deformation roadways was proposed, and the field application effect was verified. The results showed that under natural geological conditions, the 2603 air inlet roadway was located within the influence range of the Wenwangshan South normal fault, which was significantly affected and controlled by the fault. The included angle between the roadway extension direction and the maximum principal stress was 74°, which was not conducive to the stability of the roadway. The range of the roadway loose zone was large. Under the existing support conditions, the surrounding rock could not form a relatively stable structure, which was one of the main reasons for the large deformation of the surrounding rock in the dynamic pressure roadway. The 2603 air inlet roadway was affected by the mining of both the adjacent working face and the 2603 working face. The stresses were superimposed, and the roadway was greatly deformed and damaged. A new grouting material was developed. A crosslinking agent prepared by toluene diisocyanate and polyether polyol was added to the existing polyurethane material to form a new grouting material, and a complete supporting technical scheme was proposed. The field application results showed that the displacement and floor heave of both sides of the roadway were reduced by approximately 87%, the deformation and failure of the coal and rock mass of the roadway were effectively controlled, and the deformation of the dynamic pressure roadway was greatly reduced.