Viscosity and its relationship to crystallization in a binary system of saturated triacylglycerides and sesame seed oil

This paper describes the relationship of viscosity with the crystallization process in a binary system formed by sasame oil and different concentrations of tripalmitin (TP) and tristerian (TS) (0.0, 0.032, 0.098, 0.18, 0.26, 0.344 g/dL). The behavior of the reduced viscosity (η_red) indicated that TP and TS affected the native bilayer lamellar organization of sesame oil triacylglycerides. The behaviour of η_red at TP or TS concentrations ≤0.098 g/dL suggested that, as a result of intermolecular interactions between the saturated triacylglyceride and the unsaturated triacylglycerides of sesame oil, the oil solution developed lamellar structures with a smaller size than the native structures in sesame oil. At TP or TS concentrations >0.098 g/dL, the behavior of η_red indicated that TP or TS segregated out of the lamellar structure as the temperature was decreased. The kinetics of the segregation phenomenon was a function of the concentration of saturated triacylglyceride and the type of triacylglyceride (i.e., TP or TS), and was favored by an increase in the shear rate. In all situations, the temperature of nucleation was achieved when η_red=0, which may represent the point at which the interfacial energy between sesame oil and the developing nuclei achieved its maximum value. The higher the intermolecular interaction between the TP or TS and the triacylglyceride structure of the sesame oil, the lower the temperature at which η_red=0 in the oil solutions. As a result, the diffusion term (i.e., viscosity of the liquid phase) became a limiting factor for crystal growth rate, especially at TP and TS concentrations ≤0.18 g/dL.     

Extraction and solution properties of the galactomannan from the seeds of Cassia javanica L.

The galactomannan from the seed of Cassia javanica L. was extracted in 26% yield and submitted to viscosity measurements. The intrinsic viscosity [η] = 11.3 dl/g was determined at 25 °C and used to calculate the viscosity average molecular weight, Mˉ_v = 1.5 × 10⁶. Variation of the specific viscosity at zero shear rate as a function of the coil overlap parameter revealed two critical concentrations, C* = 0.54 and C** = 2.6 g/l, more frequently observed for rigid polysaccharides. Received: 23 July 1997/Revised: 29 September 1997/Accepted: 3 October 1997     

Synthesis and characterization of soluble polyamides from bis-[(4′-aminobenzyl)-4-benzamide] ether and various diacids

New aromatic diamine containing preformed amide, ether, and methylene; bis-[(4′-aminobenzyl)-4-benzamide] ether (BABE), was synthesized and characterized by FT-IR, NMR, and mass spectrometry. Aromatic–aliphatic polyamides were prepared from BABE with aliphatic/aromatic diacids via Yamazaki’s polymerization. The polyamides were characterized by FT-IR, ¹H NMR, inherent viscosity [η_inh], solubility tests, differential scanning calorimetry [DSC], thermogravimetric analysis [TGA], and X-ray diffraction [XRD]. Polyamides had inherent viscosities 0.35–0.84 dL/g, soluble in aprotic polar solvents like N-methyl-2-pyrrolidone, N, N-dimethyl acetamide and dimethyl sulphoxide containing LiCl due to an amorphous to partially crystalline morphology; as XRD patterns indicated. DSC analysis of polyamides showed glass transition temperatures 166–268 °C. Polyamides showed high thermal stability as they did not degrade below 300 °C, had 10% weight loss temperature higher than 375 °C, and the char yields at 900 °C were 22–55%; indicating potential applications as engineering materials.     

Viscosity-structure relationship of dilute triglycerides’ solutions correlation to retention time in reversed-phase liquid chromatography

The dynamic viscosity (η) of dilute solutions of the trigly-cerides triolein, trilinolein, trimyristin, tristearin and tripalmitin in benzene at temperatures in the range of 25–37°C can be expressed in terms of the viscosity of the solvent (η₀), the triglycerides’ concentration (C) and structural characteristics, such as the length of the carbon chains (CN) and the number of double bonds (DB). The simple empirical equation ln η=k₀+k₁ ln η₀+k₂ CN+k₃ DB+k₄ C satisfactorily describes (within the experimental error of 0.002 cp) the solution viscosity of triglycerides inp-xylene when using the coefficients derived from the benzene solutions. In addition, a relation is derived extending the application of the above-mentioned empirical equation to multicomponent dilute solutions. This last one describes the dilute solution viscosity of natural oils in benzene and agrees with the experimental values. Furthermore, the triglycerides that have equal partition numbers in reversed-phase liquid chromatography (RPLC) exhibit equal values for the solution viscosity. This relationship is similar to the equation expressing the retention time of RPLC in terms of the structure of the solute. Hence, it is suggested that the shape of the solute, which is a significant factor for the solution viscosity of triglycerides, also plays an important role in the retention mechanism of RPLC.     

Fullerene lipids: Synthesis of novel nitrogen-bridged [60]fullerene fatty ester derivatives

Reactions of methyl 6-azido-hexanoate, 8-azido-octanoate, and 12-azido-dodecanoate with [60]fullerene (1) gave the corresponding aza-[60]fullerene ester derivatives (2a-2c, 22–35% based on the amount of [60]fullerene reacted). The nitrogen atom is bonded to the [60]fullerene cage to yield a “[5,6]-open” type aza substructure. This was confirmed by the appearance of 30–31 sp ² signals at δ_C 133–147 in the carbon nuclear magnetic resonance spectra. Reaction of methyl 11-azido-7-undecynoate with [60]fullerene furnished a mixture of aza-[60]fullerene (2d, 53%) and aziridine-[60]fullerene (2e, 38%) ester derivatives. Compound 2e was identified as the “[6,6]-closed” type aziridine-[60]fullerene derivative, which displayed 10 sp ² signals in the region δ_C 140–145 and one signal at δ_C 85.05 for the sp ³ carbons of the cage. Refluxing a solution of compound 2d in toluene for 50 h gave about 50% yield of compound 2e, but not vice versa.     

Synthesis and Crystal Structures of Two New Coordination Polymers Based on Diphenic Acid

Two new metal coordination polymers [Zn(dpa)(bim)] _n and [Ni(dpa)(bpp)] _n , (H₂dpa = 3,4′-Biphenyl-dicarboxylic acid, bim = Benzimidazole and bpp = 1,3-Di (4-pyridyl)-propane) have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses reveal that the 3,4′-diphenic acids act as bridging ligands, exhibiting three coordination modes to link metal ions: μ ₂–η ¹: η ¹, μ ₁–η ¹: η ⁰ and μ ₁ –η¹: η¹. Compound 1 demonstrates a one-dimensional zigzag chain. There exists intermolecular hydrogen bonding interactions in compound 1 which lead to form supramolecular structure. Compound 2 is a two-dimensional (4,4) net, and further assembled twofold interpenetrating net. Furthermore, compound [Zn(dpa)(bim)] _n shows intense photoluminescence at room temperature.     

Viscosity behavior and chain conformation of a (1→3)-α-glucan from Ganoderma lucidum

Summary Seven fractions of a (1→3)-α-D-glucan from Ganoderma lucidum have been studied by light scattering, sedimentation equilibrium, and viscometry in dimethylsulfoxide (DMSO) containing 0.25 M lithium chloride at 25°C. The intrinsic viscosity [η] - molecular weight relation for this glucan in the mixed solvent is found to be represented approximately by [η] = 0.071 M _w ^0.60 cm³ g⁻¹ in the range of weight-average molecular weight M _w studied, i.e., from 8 × 10³ to 4.4 × 10⁵. Its analysis based on current theories for wormlike chains shows that, without excluded volume effect, the (1→3)-α-D-glucan chain is characterized by a linear mass density of 380 nm⁻¹, a Kuhn segment length of about 3 nm, and a diameter of 1.2 nm and is somewhat more extended but more flexible than amylose, a (1→4)-α-glucan, in DMSO. Received: 28 July 1998/Accepted: 18 August 1998     

Synthesis of poly(ethylene terephthalate-co-isophthalate) via ring-opening polymerization of their cyclic oligomers

Syntheses of poly(ethylene terephthalate-co-isophthalate) (PET-co-PEI) were achieved via ring-opening copolymerization of corresponding cyclic oligoesters. The ring-opening polymerization (ROP)-PET-co-PEI were prepared by equilibrating an equimolar amount of cyclic oligo(ethylene terephthalate) and cyclic oligo(ethylene isophthalate) using di-n-butyltin oxide catalyst under high concentration conditions at 270 and 290 °C for 8 and 12 h. The copolyesters were obtained in yields of up to 91% with the inherent viscosity (η _inh) of up to 2.89 dl/g indicating the drastically high molecular weight compared with the conventional and ROP routes for the synthesis of PEI. The differential scanning calorimetry data of ROP-PET-co-PEI showed the melting temperatures above 400 °C indicated the potential used in high temperature application.     

Synthesis of poly-p-phenylenebenzobisthiazole used for fabrication of a thermostable, high-modulus fibre

A method was developed for synthesis of poly-p-phenylenebenzobisthiazole (PPBT) from 2,5-diamino-1,4-dimercaptobenzene diphosphate (DADMB) and terephthalic acid (TPA) in a solution of polyphosphoric acid (PPA) with a 12–15 wt. % concentration of PPBT with a molecular weight of 34,000–38,600 ([η] = 24.5–28.8 dl/g). It was shown that a high concentration of P₂O₅ in PPA, which should be 85.5–86.5 wt. % at the end of the reaction, is one of the basic conditions for obtaining a high-molecular-weight polymer from DADMB diphosphate and TPA. The synthesized liquid-crystalline polymers with a high molecular weight and concentration of 14–15 wt. % in PPA solution were used in the form of polycondensation solutions for spinning high-modulus PPBT fibres. Translated fromKhimicheskie Volokna, No. 6, pp. 35–39, November–December, 1998. We would like to thank L. P. Mil'kova for participating in the x-ray diffraction studies and discussing the results.     

5,9,23-Triacontatrienoic methyl ester,an elastase inhibitor from the marine sponge Chondrilla nucula

A polyethylenic fatty ester was isolated from the marine sponge Chondrilla nucula. The structure was elucidated through NMR spectral data and MS analysis as 5,9,23-triacon-tatrienoic methyl ester 1. Compound 1 is an elastase inhibitor [ID₅₀=10 μg/mL (2·10⁻⁵M)].     

From 1-<Emphasis Type="SmallCaps">d</Emphasis> to 3-<Emphasis Type="SmallCaps">d</Emphasis> Supramolecular Structures Derived from Diphenic Acid and Auxiliary Ligands

Four novel compounds [Co(Hdpa) ₂(4,4′-bipy)₂]_n (1), {[Ni(dpa)(2,2′-bipy)(H₂O)](H₂O)}_n, (2), [Ni(dpa)(im)₃]_n (3) and [Zn(dpa)(im)]_n (4) [H₂dpa = 2,4′-diphenyl-dicarboxylic acid, 4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine and im = imidazole] were synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. X-ray crystallography shows that the 2,4′-diphenic acid exhibits three coordination modes to link the metal ions: μ ₁ −η¹: η¹/μ ₀ −η⁰: η⁰, μ ₁−η ¹: η ⁰/μ ₂−η ¹: η ¹ and μ ₁−η ¹: η ⁰/μ ₁−η ¹: η ⁰. Compound 1 has a 1D supramolecular structure. Compounds 2 and 3 are 3D supramolecular structures. Compound 4 is a 2D supramolecular structure. All the compounds, 1–4, are self-assembled to form supramolecular structures through hydrogen bonding interactions.     

Viscometric Study of Dilute Poly(Acrylonitrile–Ammonium Itaconate) Solutions

The intrinsic viscosity of dilute poly(acrylonitrile–ammonium itaconate) copolymer solution in dimethyl sulfoxide was studied by viscometry. Abnormal phenomena of the η_sp/c versus c curves of poly(acrylonitrile–ammonium itaconate) were found. Owing to the effect of NH₄ ⁺, there were three anomalistic turning points in the curve of the Huggins dependence compared with other polyacrylonitrile copolymers.     

Copolymerization of 1-butene and 1-hexene with supported titanium catalyst

With TiCl₄/MgCl₂ (Ti) and Al(i-Bu)₃ (Al) as catalysts, the thermoplastic copolymer of 1-butene(Bt) and 1-hexene(He) was synthesized successfully. The effects of Bt/He, Ti/(He+Bt), Al/Ti, temperature and reaction time on conversion, catalyst efficiency(CE), intrinsic viscosity([η]) and insoluble content were studied. The copolymer was analyzed with Fourier transform-infrared (FTIR) and nuclear magnetic resonance (¹H-NMR). Results showed that the optimal polymerization conditions were: He/Bt = 0.25, temperature 40°C−50°C, Al/Ti = 400−500, Ti/(Bt+He) = 3 × 10⁻⁵ − 4 × 10⁻⁵, time 4 h. Intrinsic viscosity was found to increase with increasing Ti/(Bt+He) and decreasing Al/Ti and polymerization temperature. When the molar content of He, Al/Ti and polymerization temperature increased, the insoluble content in CH₂Cl₂ of copolymers decreased. When Ti/(Bt+He) and reaction time increased, the insoluble content in CH₂Cl₂ of copolymers also increased. The crystallization and stereoregularity of poly(1-butene) decreased with the addition of He. Translated from China Synthetic Rubber Industry, 2006, 29(6): 429–434 [译自: 合成橡胶工业]     

Influence of Extraction Processing on Rheological Properties of Rapeseed Oils

Rheological behavior of six crude rapeseed oils with different extraction methods including hot-pressing, solvent-extraction and cold-pressing were studied. Viscosities of the oils were measured with shear rates ranging from 0.1 to 200 s⁻¹ at three different temperatures. The Casson model was used to fit the experimental data and the Arrhenius equation was applied to estimate the energy of activation for viscosity (E _a). The extraction methods affected the total tocopherol, total phytosterols, total phenols, phosphorus and fatty acid composition. The hot-pressed medium-erucic rapeseed oil (HMRO) had the greatest viscosity, and the cold-pressed low-erucic rapeseed oil (CLRO) had the lowest viscosity among all the oils with shear rates >5 s⁻¹ at 10 °C. The crude rapeseed oils exhibited Newtonian behavior at higher shear rates. The significant difference of viscosity of the six oils was reduced with increasing temperature, and there was no significant change (P > 0.01) among the oils with a shear rate of 100 s⁻¹ at 50 °C. According to the values of E _a, the following order of a change in viscosity was obtained as follows: CMRO > SMRO > HMRO > CLRO > SLRO > HLRO(C, cold pressed; S, solvent extracted; H, hot pressed; M, medium erucic; L, low erucic; RO, rapeseed oil). Minor components may be the contributing factors for the values of E _a of rapeseed oils. The higher shear limiting viscosity (η_c) values calculated by the Casson model decreased as the temperature increased, but no significant change (P > 0.01) was observed for η_c by using different extraction methods at 50 °C.     

Synthesis,characterization and acidochromism of Poly (2-<Emphasis Type="Italic">N,N</Emphasis>–dimethylamino-4,6-Bis (2-thienyl)-pyrimidine)

A new monomer (2-N,N-dimethylamino-4,6-Bis (2-thienyl)–pyrimidine) was synthesized and its homopolymer was successfully prepared by using Ferric trichloride (FeCl₃) as an oxidant. The structure of the polymer and monomer was fully characterized by ¹H–NMR, FTIR, UV-vis, Fluorescent spectroscopy and X-ray diffraction pattern. The polymer gives rise to a band at λ _max = 391 nm. The polymer showed the PL spectrum, gave a peak at 507 nm.We have observed that the polymer was sensitive to inorganic acids and the acidochromism behavior was investigated applying organic acid such as CF₃COOH. The corresponding UV-Vis peaks were observed at 464 nm and 357 nm respectively. X-ray diffraction data shows that polymer has a certain crystallinity. The polymer exhibited an [η] value of 0.26 dLg⁻¹ at 25 °C in H₂SO₄ (w = 98%).     

Correlating viscosity with temperature and other properties

Simple viscosity equations based on linearities [1/η^e (or φ^e) vs. T; T/η^e vs. T and φ^e vs. P; (η, viscosity; φ, fluidity; T, temperature; and P, any property or property function linear with T, such as, density, refractivity, and surface tension)] are given for glycerol, triglycerides, glyceride oils, n-fatty acids, esters, an alcohol, and an amine.     

Effect of ZnCdTe-Alloyed Nanocrystals on Polymer–Fullerene Bulk Heterojunction Solar Cells

The photovoltaic properties of solar cell based on the blends of poly[2-methoxy-5-(2-ethylhexoxy-1,4-phenylenevinylene) (MEH-PPV), fullerene (C60), and ZnCdTe-alloyed nanocrystals were investigated. Comparing the spectral response of photocurrent of the MEH-PPV:C₆₀ (+ZnCdTe) nanocomposite device with that of the devices based on MEH-PPV:C₆₀ and pristine MEH-PPV, one can find that the nanocomposite device exhibits an enhanced photocurrent. In comparing the composite devices with different ZnCdTe:[MEH-PPV + C₆₀] weight ratios of 10 wt% (D_1–1), 20 wt% (D_1–2), 40 wt% (D_1–3), and 70 wt% (D_1–4), it was found that the device D_1–3 exhibits the best performance. The power conversion efficiency (η) is improved doubly compared with that of the MEH-PPV:C₆₀ device.     

Thiohydroxamic esters

Summary N-Hydroxypyridine-2-thione derivativesIa-c and N-hydroxy-4-methylthiazole-2(3H)-thione derivativesIIa-b act as chain transfer agents in free radical polymerizations of methyl methacrylate (C _x =0.6–4.3), styrene (C _x =0.32–3.9), methyl acrylate (C _x =3.1–20), and vinyl acetate (C _x =9.7–80) at 60°C. Some retardation occurs with vinyl acetate and methyl acrylate.Ib also has the property of initiating the polymerization of methyl methacrylate photochemically, whileIIb acts as a thermal initiator. The chain transfer constants ofIIb make it particularly suitable for regulating molecular weight in batch polymerizations of methyl methacrylate and styrene.     

Synthesis and characterization of new aromatic polyesters based on 8,16-methano-16H-dinaphtho[2,1-d:1′,2′-g][1,3]dioxocin-2,14-diol

The bisphenol monomer containing dinaphthodioxocin group viz., 8,16-methano-16H-dinaphtho[2,1-d:1′,2′-g][1,3]dioxocin-2,14-diol (MDDD) was synthesized from commercially available 2,7-dihydroxynaphthalene and malonaldehydetetramethyl acetal and fully characterized by FT-IR, ¹H, ¹³C NMR and mass spectroscopies. A series of new aromatic polyesters was synthesized by phase transfer-catalysed interfacial polycondensation or high temperature solution polymerization method. Optimal conditions for polyesterification were obtained via study of the model compounds. These polyesters were characterized by spectroscopic technique, viscosity measurement, solubility, thermal stability, DSC, and elemental analysis. Inherent viscosities and number average molecular weights (M_n) of polyesters were in the range 0.33–0.74 dl/g and 13,130–38,000 (Gel Permeation Chromatography, polystyrene standard). All of the new polymers show very good solubility in polar aprotic solvents and could be cast into transparent, flexible and apparently tough films. The glass transition temperature (T_g) of polyesters was in the range of 152–289 °C. Polyesters derived from MDDD and eight aromatic diacid chlorides did not show any weight loss below 330 °C and retained 23–43% weight at 600 °C. The temperature at 10% weight loss (T₁₀), determined from thermogravimetric analysis of polyesters, was in the range 420–434 °C indicating their good thermal stability.     

Solution properties of polymacromonomers consisting of polystyrene

Summary Dynamic light scattering measurements have been made on 14 samples of a polymacromonomer consisting of polystyrene with 15 styrene side-chain units in cyclohexane at 34.5°C (the theta point) to determine the translational diffusion coefficient D as a function of molecular weight. The dependence of D on the main-chain length is analyzed on the basis of the wormlike chain by taking into account the end effect arising from side chains near the main-chain ends. The model parameters describing this dependence, i.e., the Kuhn segment length (11.5 ± 1.5 nm), the linear mass density (5600 ± 700 nm⁻¹), the diameter (5.2 ± 0.5 nm), and the end-effect parameter δ (2.5 ± 0.3 nm), are close to those determined previously from <S ²>_z (the z-average mean-square radius of gyration) and [η] (the intrinsic viscosity), leading to the conclusion that the wormlike chain model is capable of consistently explaining <S ²>_z, [η], and D of the polymacromonomer in the Θ solvent. Received: 8 February 2000/Accepted: 18 February 2000