Polyol Mixture Research Articles

Nanoclay-Flexible Polyurethane Nanocomposites Formulated by Recycled Polyether Polyols

Flexible polyurethane nanocomposites (PUNCs) containing recycled polyether polyols received from chemical recycling of original corresponding foams were synthesized by the incorporation of organically functionalized Cloisite 30B montmorillonite (MMT). Different amounts of MMT (1-3%w) were added to the polyol mixture prior to introducing the isocyanate portion. Recycled polyol was ranged between 10 to 30% of total polyol and MMT was maximum 3%. Thermal, morphological and mechanical properties of prepared PUNCs were studied and the results demonstrated the improvement of properties.

Synthesis of bio‐based polyurethanes from epoxidized soybean oil and isopropanolamine

AbstractEpoxidized soybean oil (ESO) and isopropanolamine were used to synthesize a new polyol mixture for preparation of bio‐based polyurethanes. The chemical synthetic route for reaction of ESO with isopropanolamine was analyzed by 1H‐NMR. The results suggested that both ester groups and epoxy groups in ESO had reacted with amino group of isopropanolamine through simultaneous ring‐opening and amidation reactions. Epoxy groups in various situations exhibited different reactivity, and the unreacted epoxy groups were further opened by hydrochloric acid. The synthesized polyol mixture had high hydroxyl number of 317.0 mg KOH/g. A series of polyurethanes were prepared by curing the synthesized polyol mixture with 1,6‐diisocyanatohexance along with different amount of 1,3‐propanediol (PDO) as chain extender. Tensile tests showed that yield strengths of the polyurethanes ranged from 2.74 to 27.76 MPa depending on the content of PDO. Differential scanning calorimetry analysis displayed one glass transition temperature in the range of 24.4–28.7°C for all of the polyurethane samples, and one melt peak at high content of PDO. Thermogravimetric analysis showed that thermal degradations of the polyurethanes started at 240–255°C. In consideration of simple preparation process and renewable property of ESO, the bio‐based polyurethane would have wide range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

PET from Used Beverage Bottles: A Material for Preparation of Biologically Degradable Copolyesters

Poly(ethylene terephthalate) from used colorless beverage bottles was solvolyzed by ethane-1,2-diol. Hydroxyl end-groups present in the mixture of polyols formed were used to initiate the polymerization of e-caprolactone (CLO) at 190 °C. Polycondensation (190 °C) of the reaction mixture containing an equilibrium amount of lactone corresponding to the reaction temperature yield an aliphatic–aromatic copolyester. A variety of copolyesters containing 20–60 mol. % CLO structural units was prepared. The microstructure of their macromolecules was analyzed using 1H NMR spectroscopy. Copolyesters were characterized by thermal analysis and tensile tests and their biodegradation potential was checked by the composting test.

Polyurethane composites derived from glycerol and molasses polyols filled with oil palm empty fruit bunches studied by TG and DMA

Polyurethane composites filled with oil palm empty fruit bunches (EFB) were prepared using molasses and glycerol based polyols (MLP and GlyP). Glycerol is a by-product of biodiesel fuel (BDF) from palm oil, and EFB a residual component of the palm oil tree. MLP or GlyP was prepared by dissolving molasses or glycerol in polyethylene glycol. In the first series of composites, the NCO/OH ratio was varied from 0.1 to 0.5 at GlyP/MLP ratio of 50/50. In the second series of composites, the GlyP/MLP ratio was varied from 100/0 to 0/100 at NCO/OH=0.4. Thermogravimetry (TG), dynamic mechanical analysis (DMA) and static mechanical tests of the above composites were carried out. It was found that thermal properties of the PU composites were markedly affected by the NCO/OH ratio and GlyP/MLP ratio. The thermal stability increased in the presence of molasses component in the polyol mixture. The segmental motion in PU composites was restricted by the presence of glycerol. Static mechanical tests indicated that the degree of cross-linking plays an important role in determining the efficiency of stress transfer from matrix to filler.

Kinetic study of the formation of lignin-based polyurethanes in bulk

The formation of lignin-based polyurethanes was monitored by Fourier transform infrared spectroscopy working in attenuated total reflectance mode (FTIR-ATR) and kinetics was analyzed according to a global second order model. The used chemical system consisted of 4,4′-methylene-diphenylene diisocyanate (MDI), polycaprolactone (PCL) of three different average-molecular weights (400, 750 and 1000) and two lignin (L) samples (Alcell (A) and Indulin AT (IAT)), incorporated at different weight contents (10%, 15%, 20% and 25%) in the polyol mixture. The polymerization reaction was carried in bulk and without the presence of any catalyst. Results showed that isocyanate conversion decreases with the increase of both lignin content and PCL molecular weight. Moreover, the Indulin AT series leaded to lower isocyanate conversions compared to Alcell counterparts. The global second order treatment showed to be dependent of lignin type and content as well as PCL molecular weight. In fact, for the studied system this model was found to be more adequate for low lignin contents. After the region of linearity, a negative deviation was always observed and found to be more pronounced with increasing the lignin content.

Physiological and biochemical analysis of overwintering and cold tolerance in two Central European populations of the spruce bark beetle, Ips typographus

Overwintering success is one of the key aspects affecting the development and outbreaks of the spruce bark beetle, Ips typographus (L.) populations. This paper brings detailed analysis of cold tolerance, and its influence on overwintering success, in two Central European populations of I. typographus during two cold seasons. Evidence for a supercooling strategy in overwintering adults is provided. The lower lethal temperature corresponds well to the supercooling point that ranges between −20 and −22 °C during winter months. The supercooled state is stabilized by the absence of internal ice nucleators and by seasonal accumulation of a mixture of sugars and polyols up to the sum concentration of 900 mM. The cryoprotective function of accumulated metabolites is probably based on increasing the osmolality and viscosity of supercooled body fluids and decreasing the relative proportion of water molecules available for lethal formation of ice nuclei. No activity of thermal hysteresis factors (stabilizers of supercooled state) was detected in hemolymph. Lethal times for 50% mortality (Lts50) in the supercooled state at −5, −10 or −15 °C are weeks (autumn, spring) or even months (winter), suggesting relatively little mortality caused by chill injury. Lts50 at −15 °C are significantly shorter in moist (6.9 days) than in dry (>42 days) microenvironment because there is higher probability of external ice nucleation and occurrence of lethal freezing in the moist situation.

Investigation of novel polyurethane elastomeric networks based on polybutadiene-ol/polypropyleneoxide mixture and their structure–properties relationship

Polyurethane elastomer networks were designed and synthesized based on hydroxyl terminated polybutadiene/polypropyleneoxide (HTPB/PPO) mixtures, 2,4-toluene diisocyanate and 1,4-butanediol. Various networks with different molar ratio of HTPB to PPO (0/100, 25/75, 50/50, 75/25 and 100/0) had been prepared. Depending on the length of soft segment, average functionality of polyol mixtures, mechanical and thermal properties of samples were varied. Our observations confirmed that final properties of the networks can be attributed to two synergistic factors: (a) formation of chemical network (crosslinking) and (b) soft segment length. An optimum composition was found. This optimum composition shows that both physical (hard domains) and chemical network (crosslinking) have synergistic effects. Moreover, Flory–Hugins interaction parameters of soft and hard segments were calculated. Synthesized polyurethane elastomer networks have a structure similar to semi interpenetrating polymer networks, which is named pseudo-semi-IPN. These novel polyurethane elastomer networks show higher tensile strength and economic benefit than polyurethanes which are based on other non-polar polyols.

Switchable Ionic liquids (SILs) based on glycerol and acid gases

New types of switchable ionic liquids (SILs), containing 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU), glycerol and an acid gas (CO2, SO2), were synthesized and characterized in this study. [DBU][Carbonate] or [sulfonate] were easily synthesized from a non-ionic mixture of molecular organic polyol and amidine base upon bubbling of an acid gas (CO2, SO2). Moreover, they were switched back to the original molecular solvents by flushing out the acid gas (CO2, SO2) by heating and/or bubbling an inert gas such as N2 through it. The structures of the SILs were confirmed by NMR and FTIR. The change from low polarity (molecular solvent) to high polarity (Switchable Ionic Liquid, SIL) was also indicated by the changes in properties, such as viscosity and miscibility with different organic solvents. The decomposition temperatures of the SILs were determined by means of Thermo Gravimetric Analysis (TGA) and gave values in the range of 50 °C and 120 °C for DBU-glycerol-CO2 (SIL1) and DBU-glycerol-SO2 (SIL2), respectively. Due to the reasonable decomposition temperatures, these novel SILs can be employed in multiple applications.

Production of arabitol from glycerol: strain screening and study of factors affecting production yield

Glycerol is a major by-product from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotolerant, were first screened in this study. No strains were found to produce large amounts of xylitol as the dominant metabolite. Some produced polyol mixtures that might present difficulties to downstream separation and purification. Several Debaryomyces hansenii strains produced arabitol as the predominant metabolite with high yields, and D. hansenii strain SBP-1 (NRRL Y-7483) was chosen for further study on the effects of several growth conditions. The optimal temperature was found to be 30°C. Very low dissolved oxygen concentrations or anaerobic conditions inhibited polyol yields. Arabitol yield improved with increasing initial glycerol concentrations, reaching approximately 50% (w/w) with 150 g/L initial glycerol. However, the osmotic stress created by high salt concentrations (≥50 g/L) negatively affected arabitol production. Addition of glucose and xylose improved arabitol production while addition of sorbitol reduced production. Results from this work show that arabitol is a promising value-added product from glycerol using D. hansenii SBP-1 as the producing strain.

Xylitol gum, plaque pH and mutans streptococci

This was a randomised clinical trial (note that the initial screening used a cluster randomised in part design). A total of 176 children (7-9 years old) with high MS scores were randomised into equal groups. For 6 months the xylitol group chewed five times during the day, 11.6 grams of a mixed gum containing 36.6% xylitol and other polyols (34.5%). while the control group chewed an identical dose of a non xylitol gum sweetened with a mixture of different polyols (71.1%). At baseline, 3 months, 6 months and 9 months (3 months after chewing) children were assessed for both plaque acidogenicity (after sucrose challenge) and salivary MS. Statistically significant differences were found between both groups at 3, 6 and 9 months, in 'area under the curve' (AUC) graphs, with lower plaque pH values in the xylitol group at 3 and 6 months and decreasing difference at 9 months. There was no significant difference between the maximum pH fall in both groups, and only small differences in minimum pH values at 3 and 6 months. There was significantly lower MS level in the xylitol compared with the control group. In addition there was a significant relationship between changes in MS levels, and changes in AUC. This randomised clinical trial suggests that the use of high-dose xylitol chewing gum has beneficial effects on plaque pH and MS in children at high risk of caries.

Plasticization of corn starch by polyol mixtures

Polyol mixtures including mixture of conventional plasticizer glycerol and higher molecular weight polyol (HP) such as xylitol, sorbitol and maltitol were used to plasticize corn starch by melt-blending method, and effect of the polyol mixture on the pocessibility, microstructures, thermal stability and mechanical properties of these starch composites (SC) were investigated. The introduction of HP providing greater processing torque can dramatically reduce the strong molecular chain interaction in starch without obvious residual starch granules in the starch composites. The increasing of the molecular weight and content of HP in polyol mixture is beneficial for the significant enhancement of the thermal stability and mechanical strength of the starch composite. Meanwhile, the addition of HP besides conventional glycerol increases the modulus and phase transition temperature of the starch composite too.

Analysis of volatile organic compounds in polyurethane coatings based on Eucalyptus sp. bio-oil pitch using comprehensive two-dimensional gas chromatography (GC × GC)

The development of biomass products seems to be a near-term alternative to fossil derivatives, which aim to mitigate climate changes. It is therefore necessary to investigate whether biomass technologies are really safe and without environmental impact. This work presents a characterization of the volatiles that are released from biopitch and its polyurethane films. Biopitch was obtained via the distillation of Eucalyptus sp. bio-oil; it was recovered by the condensed smoke that was obtained during slow pyrolylis, which is a process that is used to produce charcoal for the iron-making industry in Brazil. Biopitch and castor oil mixtures, in different proportions, were used as polyols in the polyurethane synthesis. The reactions were carried out when the polyol mixtures were stirred together with polymeric MDI (4,4′ methylene diphenyl diisocyanate) NCO/OH = 1.1 and dibutyltin dilaurate as a catalyst. The films were analyzed by comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC/TOFMS). The best experimental conditions that permit the identification of 104 volatile organic compounds were determined. Although the analysis was not quantitative, it was possible to conclude that a large content of biopitch led to the release of a large number of different substances. The main compounds that were released are phenolic methoxyl substituted substances with one aromatic ring and a low toxicity. Due to its high resolution and sensitivity, the methodology that was used seems to be adequate for the analysis of other macromolecular fractions (biopitches) and polymeric materials that are derived from bio-oils.

Viscosity and density of binary mixtures of alcohols and polyols with three carbon atoms and water: equation for the correlation of viscosities of binary mixtures

Measurements have been made of the viscosity and density of binary mixtures of alcohols and polyols with three carbon atoms and water at 298.15 K and at atmospheric pressure, as a function of the mole fraction. Fits have been made of the experimental values corresponding to the excesses of molar volume (V E), the deviations of viscosity (Δη), and the excesses of Gibbs free energy of activation (G* E), by means of the Redlich–Kister equation. A new correlation equation is presented for studying the viscosity of such mixtures, and comparisons are made of the experimental values of viscosity versus the values obtained by means of the mentioned equation and the models of Heric and McAllister. Likewise, and with the purpose of corroborating the validity of the proposed correlation equation, the latter is applied to other reference binary mixtures.

Sorbitol production from lactose by engineered Lactobacillus casei deficient in sorbitol transport system and mannitol-1-phosphate dehydrogenase

Sorbitol is a sugar alcohol largely used in the food industry as a low-calorie sweetener. We have previously described a sorbitol-producing Lactobacillus casei (strain BL232) in which the gutF gene, encoding a sorbitol-6-phosphate dehydrogenase, was expressed from the lactose operon. Here, a complete deletion of the ldh1 gene, encoding the main L-lactate dehydrogenase, was performed in strain BL232. In a resting cell system with glucose, the new strain, named BL251, accumulated sorbitol in the medium that was rapidly metabolized after glucose exhaustion. Reutilization of produced sorbitol was prevented by deleting the gutB gene of the phosphoenolpyruvate: sorbitol phosphotransferase system (PTS(Gut)) in BL251. These results showed that the PTS(Gut) did not mediate sorbitol excretion from the cells, but it was responsible for uptake and reutilization of the synthesized sorbitol. A further improvement in sorbitol production was achieved by inactivation of the mtlD gene, encoding a mannitol-1-phosphate dehydrogenase. The new strain BL300 (lac::gutF Deltaldh1 DeltagutB mtlD) showed an increase in sorbitol production whereas no mannitol synthesis was detected, avoiding thus a polyol mixture. This strain was able to convert lactose, the main sugar from milk, into sorbitol, either using a resting cell system or in growing cells under pH control. A conversion rate of 9.4% of lactose into sorbitol was obtained using an optimized fed-batch system and whey permeate, a waste product of the dairy industry, as substrate.

Characterization of castor oil/polycaprolactone polyurethane biocomposites reinforced with hemp fibers

The thermal and mechanical properties of castor oil/polycaprolactone-based polyurethane (CPU) films and polyurethane biocomposites reinforced with hemp fibers (HCPU) were investigated. Although similar films can be synthesized from petroleum, the main interest in studying these biomass-based composites is based on the fact that both fiber and matrix are derived from renewable resources. In this study, castor oil was used as a polyol for polyurethane films and hemp fiber was used to reinforce the biocomposites. To control the mechanical properties of CPU and HCPU, polycaprolactone diol (PCL) was added to the polyol mixture. Varying the mixing ratio of castor oil and PCL, the thermal and mechanical properties of the CPU and HCPU samples were investigated by using FT-IR, DSC, DMTA, Minimat, and SEM. In an attempt to improve interfacial adhesion between the fiber and matrix biocomposites, hemp fiber was reacted with MDI. FE-SEM micrographs showed that the surface of the hemp fiber became smoother after reaction with MDI. Urethane bonding formation was confirmed by FT-IR.

Ubiquitous Water-Soluble Molecules in Aquatic Plant Exudates Determine Specific Insect Attraction

Plants produce semio-chemicals that directly influence insect attraction and/or repulsion. Generally, this attraction is closely associated with herbivory and has been studied mainly under atmospheric conditions. On the other hand, the relationship between aquatic plants and insects has been little studied. To determine whether the roots of aquatic macrophytes release attractive chemical mixtures into the water, we studied the behaviour of mosquito larvae using olfactory experiments with root exudates. After testing the attraction on Culex and Aedes mosquito larvae, we chose to work with Coquillettidia species, which have a complex behaviour in nature and need to be attached to plant roots in order to obtain oxygen. This relationship is non-destructive and can be described as commensal behaviour. Commonly found compounds seemed to be involved in insect attraction since root exudates from different plants were all attractive. Moreover, chemical analysis allowed us to identify a certain number of commonly found, highly water-soluble, low-molecular-weight compounds, several of which (glycerol, uracil, thymine, uridine, thymidine) were able to induce attraction when tested individually but at concentrations substantially higher than those found in nature. However, our principal findings demonstrated that these compounds appeared to act synergistically, since a mixture of these five compounds attracted larvae at natural concentrations (0.7 nM glycerol, <0.5 nM uracil, 0.6 nM thymine, 2.8 nM uridine, 86 nM thymidine), much lower than those found for each compound tested individually. These results provide strong evidence that a mixture of polyols (glycerol), pyrimidines (uracil, thymine), and nucleosides (uridine, thymidine) functions as an efficient attractive signal in nature for Coquillettidia larvae. We therefore show for the first time, that such commonly found compounds may play an important role in plant-insect relationships in aquatic eco-systems.

Esters of methylolcyclohexanols/ones as synthetic base lubricants

PurposeThe purpose of this paper is to examine the preparation of asymmetric mixed esters of methylolcyclohexanols in order to decrease the pour point and increase the thermal stability of base oils.Design/methodology/approachThe aldol condensation reaction of cyclohexanone with paraformaldehyde is modified to give mixture of alicyclic polyols. The obtained mixture was subsequently esterified by different pure and mixed linear mono carboxylic acids to give asymmetric mixture of esters of methylolcyclohexanols/ones.FindingsThe obtained base lubricants showed better wear preventive characteristcs (four‐ball rolling contact test) compared with previously reported and commercially available ester base lubricants.Research limitations/implicationsBecause of the complexity of the obtained mixture, it was impossible to study the structure and composition of the obtained products by modern techniques such as high field NMR spectroscopy.Practical implicationsThe obtained materials are slightly acidic and should be neutralized before use or formulation.Originality/valueThe paper presents a new process for obtaining synthetic ester base lubricants from mixed polyols of neo structure, which was obtained from aldol condensation reaction of cyclohexanone and paraformaldehyde, and linear aliphatic monocarboxylic acids. The key step in this process is modifying the reaction condition for obtaining mixture of polyols, and not pure 2,2,6,6‐tetramethylolcyclohexanol. This allows one to obtain asymmetrical and complex mixture of esterification products, which is favored in the production of synthetic ester base stocks, having excellent viscosity‐temperature properties, decreased pour point, and increased thermal stability. The synthesized ester base lubricants also show excellent viscosity‐temperature properties compared with ester base lubricants of the same family.

Effect of type and content of binary polyol mixtures on physical and mechanical properties of starch-based edible films

The present study investigated effects of binary mixtures (1:1) of glycerol, xylitol and sorbitol at various concentrations on physical and mechanical properties of potato starch-based edible films stored at various relative vapor pressures (RVP). Edible films were prepared by casting using suspension of binary polyol mixtures (20–50% of solids), potato starch (50–80% of solids) and distilled water which was heated to gelatinize starch. Water sorption of films was affected by the type and content of binary polyol mixture. Water vapor permeability (WVP) of films was found to increase as the content and plasticization effect of binary polyol mixture as well as RVP gradient increased. Young’s modulus of films was observed to decrease with the concurrent increase of elongation at break as the plasticization and the content of binary polyol mixture increased at RVP of 33%. Both tensile strength and elongation at break decreased when films were plasticized at the high content of binary polyol mixtures and stored at the RVP of 54% and 76%. Crystallization of polyols was not observed when binary polyol mixtures were used as plasticizers.

Production of Polyols from Canola Oil and their Chemical Identification and Physical Properties

AbstractThe feasibility of a method based on ozonolysis and hydrogenation reactions for the production of polyols from unsaturated canola oil has been demonstrated. Polyol products with primary alcohol functional groups at position nine of each fatty acid ester in the original triacylglycerol have been produced from canola oil. Short straight‐chain alcohols were also produced and were removed by wiped‐blade molecular distillation. The pure components of the polyol, i.e. mono‐ol, diol and triol were separated by flash chromatography, and identified by Fourier‐transform infrared (FTIR), 1H‐nuclear magnetic resonance (NMR), 13C‐NMR as well as mass spectrometry. Polyol identification was facilitated by the use of a simple high‐performance liquid chromatography (HPLC) method to determine the composition of the polyol mixture, which can be exploited as a quality‐control mechanism in designing novel polyol feedstocks. Basic correlations were established between the molecular diversity of the polyols and their physicochemical properties, such as hydroxyl number, acidity number, and viscosity. It has been found that the produced polyols are suitable for processing methods employing polyols for the production of polyurethanes and can be manipulated to create polyurethanes with desirable properties.

Towards Perfunctionalized Dodecahedranes—En Route to C20 Fullerene

"One-pot" substitution of the twenty hydrogen atoms in pentagonal dodecahedrane (C(20)H(20)) by OH, F, Cl, and Br atoms is explored. Electrophilic insertion of oxygen atoms with DMDO and TFMDO as oxidizing reagents ended, far off the desired C(20)(OH)(20), in complex polyol mixtures (up to C(20)H(10)(OH)(10) decols, a trace of C(20)H(OH)(19)?). Perfluorination was successful in a NaF matrix but (nearly pure) C(20)F(20) could be secured only in very low yield. "Brute-force" photochlorination (heat, light, pressure, time) provided a mixture of hydrogen-free, barely soluble C(20)Cl(16) dienes in high yield and C(20)Cl(20) as a trace component. Upon electron-impact ionization of the C(20)Cl(16) material sequential loss of the chlorine atoms was the major fragmentation pathway furnishing, however, only minor amounts of chlorine-free C(20) (+) ions. "Brute-force" photobrominations delivered an extremely complex mixture of polybromides with C(20)HBr(13) trienes as the highest masses. The MS spectra exhibited exclusive loss of the Br substituents ending in rather intense singly, doubly, and triply charged C(20)H(4-0) (+(2+)(3+)) ions. The insoluble approximately C(20)HBr(13) fraction (C(20)Br(14) trienes as highest masses) obtained along a modified bromination protocol, ultimately allowed the neat mass selection of C(20) (-) ions. The C(20)Cl(16) dienes and C(20)H(0-3)Br(14-12) tri-/tetraenes, in spite of their very high olefinic pyramidalization, proved resistant to oxygen and dimerization (polymerization) but added CH(2)N(2) smoothly. Dehalogenation of the respective cycloaddition products through electron-impact ionization resulted in C(22-24)H(4-8) (+(2+)) ions possibly constituting bis-/tris-/tetrakis-methano-C(20) fullerenes or partly hydrogenated C(22), C(23), and C(24) cages.