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Polylactide multifilament yarns were textured in order to be endowed with properties of natural staple fibre yarns for textile applications. Texturing promotes the formation of stable secondary links between the macromolecular chains. A polylactide 167/68 dtex multifilament yarn was textured under different conditions. Relaxation experiments at yield, strain softening, strain hardening and just before breaking were performed. The relaxation behaviour was studied by the application of the generalized Maxwell model. The initial stress induced when stretched, the final non-relaxed stress after relaxation and the stress relaxed at different times were determined. Variations in the relaxation behaviour were related to texturing conditions and stretching.

Water has a considerable effect on human keratin fibres, such as nails, and is therefore crucial for their cosmetic performance. Wool proteins are mild, natural, biodegradable and are sustainably produced with multiple functionalities. They have a potential for use in the cosmetic and detergent markets. The effectiveness of two wool keratin ingredients in restoring the water sorption characteristics of nails was determined. Acetone treatment modified nail water sorption, resulting in an increase in water sorption capacity and in nail permeability. The application of keratin peptides and proteins to healthy and damaged nails improved water sorption properties, reducing permeability, especially in the case of wool keratin protein treatment.

Water produces changes in the properties of human keratin fibers, such as hair and nails, and therefore plays an important role in their cosmetic performance. Reactive cosmetic treatments of hair and nails often impair fiber structure, resulting in an adverse effect on water absorption. The moisture absorption/desorption isotherm curves for untreated hair and nails and the kinetics of these processes are studied in this work. The effects of different chemical cosmetic treatments on hair and nail water absorption are also evaluated. The isotherms for these human keratinized tissues behaved as expected, with a characteristic hysteresis between moisture uptake and desorption. Human nails showed a lower moisture regain and a much lower diffusion coefficient with respect to human hair. Permeability, directly related to the diffusion coefficient, increased with the degradation treatment. The diffusion coefficient was important in determining the integrity of keratin fibers.

Most beauty care products and treatments primarily affect the cuticle layers of hair fibers. The resulting damage has an adverse effect on hair water absorption. Water changes a wide variety of properties of human hair and is therefore of fundamental interest. Wool proteins are mild, natural, biodegradable, and sustainably produced with multiple functionalities and potential for use in the personal care and detergent market. In this study, the effect on hair water sorption of two types of keratin samples obtained from wool is investigated. Modifications of hair water sorption due to a bleaching treatment have been demonstrated, with lower values of water sorption capacity and an increase of the fibers permeability. Applications of keratin peptides and proteins to bleached hair improved the water sorption properties of the fibers and reduced their permeability.

Polyamide 6.6 multifilament yarns are converted to crimped fibres by texturing in order to simulate the properties of natural staple fibre yarns for textile applications. Texturing is carried out by mechanical stresses (turbulences or twisting) in different atmospheres which affect crystallinity and thermal stability of yarns. Two polyamide yarns with the same linear density but consisting of filaments of different fineness were textured by the air-jet and the false-twist procedures. The influence of texturing conditions and filament fineness on crystallinity and thermomechanical behaviour and dimensional stability were studied by TMA and DSC. The air-jet texturing procedure leads to a slight increase in crystallinity of yarns whereas the false-twist texturing procedure was more effective especially when thicker filaments were textured. The inflection point of the shrinkage curve before melting was a good estimator of the effective temperature of yarn texturing.

High-elevation endorreic lakes in the Southern Altiplano of South America represent a major source of local biodiversity. Size and depth of wetlands in Northwest Argentine (NWA) and Southwest Bolivia (SWB) have shown to be very sensitive to basin hidrological balances, and consequently, very vulnerable to deleterious effects from climate changes. The management of these water resources requires a comprehensive knowledge of their natural variability over multiple time scales. In this study we present a multi-century reconstruction of past lake-area fluctuations in the NWA and SWB, inferred from Polylepis tarapacana tree-ring records. Between 1975 and 2009 interannual lake area fluctuations from nine lakes were quantified based on Landsat satellite images. A composite P. tarapacana tree-ring chronology was developed. Correlations analyses were performed to screen potential predictor tree-ring chronologies for reconstruction models. Inter-annual lake area fluctuations were positively correlated with inter-annual variations of the radial growth of P. tarapacana. A tree-ring chronology (601 years long) was use as predictor, in a regression model, to reconstruct the annual (January–December) mean lake area from nine endorreic lakes. The chronology captures 60% of the total variance in lake-area fluctuations and shows adequate levels of cross-validation. The twentieth century was unusual in the long-term context provided by the reconstruction; a persistent negative trend in lake area is clear in the reconstruction during the past century and is consistent with glacier retreat and other climate proxies from the Altiplano and tropical Andes. These results provide a baseline for the historical range of variability in lake fluctuations, and thus should be considered for the management of biodiversity and water resources in the region, particularly in relation to future XXI century climate scenarios.

The thermomechanical analysis is applied to characterize the shrinking process of bovine chrome leather. The interpretation of the curves obtained is performed and a value of glass transition temperature is estimated. The influence of the sampling zone on the thermomechanical parameters is discussed. The influence of different “retanning agents,” which act as crosslinking compounds on the fibrous structure of collagen, is also evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 314–322, 2001

The condensation reactions between (4-amino-2,6-dichlorophenyl)bis(2, 4,6-trichlorophenyl)methyl radical and acetylacetone or 1, 4-bis(5-methyl-2-thienyl)-1,4-butanedione yield [2,6-dichloro-4-(2, 5-dimethyl-1-pyrrolyl)phenyl]bis(2,4,6-trichlorophenyl)methyl radical (3(*)()) and [2,6-dichloro-4-[2, 5-bis(5-methyl-2-thienyl)-1-pyrrolyl]phenyl]bis(2,4, 6-trichlorophenyl)methyl radical (4(*)()), respectively. EPR studies of both radicals 3(*)() and 4(*)() in CH(2)Cl(2) solution suggest a weak electron delocalization with coupling constant values of 1.25 and 1.30 G, respectively, with the six aromatic hydrogens. Their electrochemical behavior was analyzed by cyclic voltammetry. Both radicals show reversible reduction processes at E degrees = -0.69 V and -0.61 V versus SSCE, respectively, and anodic peak potentials at E(p)(a) = 1.10 and 0.72 V, respectively, versus SSCE at a scan rate (nu) of 200 mV s(-)(1), being reversible for radical 4(*)(). X-ray analysis of radical 3(*)() shows a high value (65 degrees ) of the dihedral angle between the 2,5-dimethylpyrrolidyl moiety and the phenyl ring. Smooth oxidation of radical 4(*)() in CH(2)Cl(2) containing trifluoroacetic acid gives an ionic diradical species with a weak electron interaction (|D/hc| = 0.0047 cm(-)(1)). A Curie plot of the Deltam(s)() = +/-2 signal intensity versus the inverse of the absolute temperature in the range between 4 and 70 K suggests a triplet or a nearly degenerate singlet-triplet ground state.

The synthesis of 4,4-iminobis(2,2′,2″,4′,4″,6,6′,6″-octachlorotriphenylmethyl) diradical3, a stable organic magnetic molecule consisting of two spin-containing fragments linked by a nitrogen atom, is reported. Electron paramagnetic resonance (EPR) analysis in methyltetrahydrofuran solution (∼10–3 m) at low temperatures showed a typical fine structure (gxx=2.0042;gyy=2.0048;gzz=2.0027) of Δms=±1transition( | D/hc |=0.0071 cm–1; | E/hc |=0.0006 cm–1) as well as a broad (ΔHpp=7.5 G) and weak signal of Δms=±2 transition (g=4.124), due to an asymmetric and excited triplet state corresponding to an intramolecular spin–spin interaction which diminishes with decreasing temperature. It also showed a pair of small peaks, that might be associated with a weaker dipole–dipole interaction which diminishes with increasing temperature, emerging at both sides of a central and single peak due to a doublet state resonance corresponding to 2,2′,2″,4′,4″,6,6′,6″-octachloro-4-{3,5-dichloro-4-[bis(2,4,6-trichlorophenyl)methylene]cyclohexa-2,5-dienylideneamino}triphenylmethyl radical 4, obtained by smooth oxidation of 3. From magnetic susceptibility measurements of the sample in the solid, a linear four-spin model was applied to establish that the singlet is the ground state of the molecule and that two triplets (Jintra=–286±30 K, J′inter=–160±50 K) were the low-lying excited states. Organic solutions of 3 in air slowly oxidize to give 4, a much more persistent monoradical which is also obtained by a smooth oxidation of 3 with AgNO3 in CHCl3 . Cyclic voltammograms for the reduction of 3 and 4 in dimethylformamide (DMF) with tetra-n-butylammonium perchlorate exhibited three consecutive redox couples with standard potentials of –0.23, –0.58 and –0.74 V vs. SCE, indicating a reasonable stability of anions 3–and32– in DMF solution.

(2,6-Dichlorophenyl)bis(2,4,6-trichlorophenyl)methyl radical ( 2 ) has been prepared through a reaction sequence of five stages obtaining four new intermediate compounds 1–4 . Assignment of the structures of these compounds have been completely ascertained by means of their 1 H NMR spectra. The new persistent radical 2 has been characterized by EPR spectra and magnetic susceptibility measurements. The X-ray structural analysis of 2 shows that it adopts a propeller-like conformation with the phenyl rings twisted around their bonds to trivalent carbon. Magnetic susceptibility of 2 is characteristic of a paramagnet with a weak antiferromagnetic interaction at low temperatures (Weiss constant, Θ = −1.8 K).

The synthesis of new organic free radicals of the PTM (perchlorotriphenylmethyl) series with different substituents in the 3- and 5-positions of one phenyl ring and their α- H precursors are described. All these radicals are stable red solids with high melting points. Their electron spin resonance spectra in solution and their magnetic susceptibilities in solid are reported and commented upon. Electrochemical behavior of radical 5 by means of cyclic voltammetry is also presented.

Photochlorinations of nonachloro-3-(chloromethyl)-1,4-dihydronaphthalene (1) and nonachloro-7-(chloromethyl)-1,4-dihydronaphthalene (2) give nonachloro-3-(dichloromethyl)-1,4-dihydronaphthalene (3) and nonachloro-7-(dichloromethyl)-1,4-dihydronaphthalene (4), respectively. Dechlorination of both 3 and 4 by means of SnCl2.2H2O affords heptachloro-7-(dichloromethyl)naphthalene (5). Photobromination of heptachloro-7-methylnaphthalene (6) with Br2 results in 2-(bromomethyl)heptachloronaphthalene (8) or heptachloro-7-(dibromomethyl)naphthalene (7), depending on the reaction time. Intermediate 8 can be prepared in high yield by bromination of 6 with NBS in the presence of AIBN. Theoretical calculations in 7 indicate the existence of two energetically favoured conformers and that one of them seems to be slightly more stable than the other one. Accordingly, the 1H NMR spectra of 5, 7, and 2-(bromochloromethyl)heptachloronaphthalene (9) are temperature dependent, displaying two singlets that collapse in a sharp singlet about 100°C. Although the two conformers of 5, 7, and 9 can be detected in solution, only the most stable of each pair, at least in the case of 7, is present in solid form (X-ray analysis). A dynamic 1H NMR study shows that the barriers to rotation of CHCl2, CHBrCl, and CHBr2 groups in 5, 9, and 7 are as high as 16.8, 18.2, and 19.3 kcal mol−1, respectively. The X-ray structure of 7 is commented, and spectral data of the synthesized compounds are reported.

A new chemical method of simultaneous polymerization and doping of 2,2'-bithiophene (1) and 2,2',5',2''-terthiophene (2) using thallium(III) trifluoroacetate (TTFA) in trifluoroacetic acid (TFA) is reported. These reactions have been carried out at 20 o C and at 72 o C observing no remarkable differences in the quality of the polymers, which are undoped or compensated and purified to their neutral state by extraction with different solvents, and redoped in I 2 atmosphere

Tris(2,4,6-trichlorophenyl)carbenium hexachloro-antimonate (2), (2,6-dichloro-4-hydroxyphenyl)bis(2,4,6-trichlorophenyl)methyl radical (4) and its methyl ether derivative 5 have been synthesized and isolated as crystalline solids. In contrast to 5, radical 4 is not very stable in air, and the disappearance of 4 by aerial oxidation has been monitored by UV-vis spectroscopy. The EPR spectra of 4 and 5 are reported and commented upon.

Dichlorobis(pentachlorophenyl)germane (3) has been prepared by reaction of GeCl4 with either pentachlorophenyllithium or pentachlorophenylmagnesium chloride. After neutral hydrolysis of 3, bis(pentachlorophenyl)germanediol (8) has been isolated and characterized as a stable solid. Thermal dehydration of 8 has been studied by thermogravimetry (TG) and differential scanning calorimetry (DSC), the product being {(C6Cl5)2GeOn}. Reaction of 3 with methanol leads to dimethoxybis(pentachlorophenyl)germane (4). Reduction of 3 with LiAlH4 gives bis(pentachlorophenyl)germane (5) which, on treatment with Br2 and I2, gives dibromo- (6) and diiodobis(pentachlorophenyl)germane (7), respectively. The molecular structure of the diiodogermane 7 has been fully established by X-ray crystallography.

CCl 3 F in the presence of AlCl 3 is not only a very suitable reagent for the trifluoromethylation of polychlorobenzenes, but also for converting CCl 3 group into CF 3 group, at least in the cases of perchlorotoluene and 2,4,5-trichloro-1-(trichloromethyl)-benzene

Bis(pentachlorophenyl) silanediol (3) has been prepared by neutral hydrolysis of perchlorodiphenylsilane (2). Reduction of 2 with LiAlH4 gives bis(pentachlorophenyl) silane (4) which upon treatment with bromine gives dibromobis(pentachlorophenyl)silane (5). Reaction of 2 with methanol and ethanol leads to dimethoxybis(pentachlorophenyl)silane (6) and diethoxybis(pentachlorophenyl)silane (7) respectively. The IR spectra of 2–7, as well as the UV and 1H NMR spectra of some of these compounds, are reported. The results of thermogravimetric and differential scanning calorimetric studies on silanediol 3 are discussed. The structure of the silane 7 has been established by X-ray crystallography.

The chlorination of 2-methylnaphthalene (1) and 1-methylnaphthalene (12) by means of Silberrad's reagent (initial components: SO 2 Cl 2 , S 2 Cl 2 , and AlCl 3 ) has been performed.We describe our results concerning the synthesis of the two heptachloro(chloromethyl)naphthalenes and the Friedel-Crafts alkylation of pentachlorobenzene

The synthesis, characterization, and physical properties of perchloro-2,6-bis(diphenylmethyl)-pyridine-α,α'-ylene biradical (1) and αH-tricosachloro-2,6-bis(diphenylmethyl)pyridine-α'-yl radical (2) which present exceptionally high stabilities are reported. The synthesis of 1 and 2 have been accomplished using different strategies in order to get them separately, although 1 always contains 2 as an impurity. 1 is a molecule constituted by two trivalent carbon atoms linked by a trichlorom-pyridylene spacer which has proved to be a good ferromagnetic coupling unit. Magnetic susceptibility measurements from 4.2 to 300 K show that the ground state of 1 is the triplet being 2J=358±14 cm -1 (1.03 kcal/mol), the triplet-singlet energy gap. At low temperature, an antiferromagnetic interaction between intermolecular spines was observed (Curie temperature, θ 1 =-2.02±0.10K). The EPR spectrum of 1 in frozen 2-methyltetrahydrofuran (133 K) in the Δm s =±1 region affords three symmetric pairs of lines corresponding to a triplet species without axial symmetry with zfs parameters |D/hc|=0.0081 cm -1 . The Δm s =±2 transition follows the Curie law over the range 10.0-62.o K, supporting the highest multiplicity of the molecule in the ground state. The cyclic voltammogramm of 1 exhibits a redox couple (E°=0.18 V vs SCE) which is attributed to the reduction of this biradical to the stable anion 12 (1 - ), and a second irreversible peak (E p c = -0.25 V vs SCE) which is ascribed to the formation of the unstable dianion 13 (1 2- ). The electronic spectrum of 1 is presented and discussed

Tris(2,4,6-trichlorophenyl)carbenium hexachloro-antimonate (2), (2,6-dichloro-4-hydroxyphenyl)bis(2,4,6-trichlorophenyl)methyl radical (4) and its methyl ether derivative 5 have been synthesized and isolated as crystalline solids. In contrast to 5, radical 4 is not very stable in air, and the disappearance of 4 by aerial oxidation has been monitored by UV-vis spectroscopy. The EPR spectra of 4 and 5 are reported and commented upon.

Photochlorinations of nonachloro-3-(chloromethyl)-1,4-dihydronaphthalene (1) and nonachloro-7-(chloromethyl)-1,4-dihydronaphthalene (2) give nonachloro-3-(dichloromethyl)-1,4-dihydronaphthalene (3) and nonachloro-7-(dichloromethyl)-1,4-dihydronaphthalene (4), respectively. Dechlorination of both 3 and 4 by means of SnCl2.2H2O affords heptachloro-7-(dichloromethyl)naphthalene (5). Photobromination of heptachloro-7-methylnaphthalene (6) with Br2 results in 2-(bromomethyl)heptachloronaphthalene (8) or heptachloro-7-(dibromomethyl)naphthalene (7), depending on the reaction time. Intermediate 8 can be prepared in high yield by bromination of 6 with NBS in the presence of AIBN. Theoretical calculations in 7 indicate the existence of two energetically favoured conformers and that one of them seems to be slightly more stable than the other one. Accordingly, the 1H NMR spectra of 5, 7, and 2-(bromochloromethyl)heptachloronaphthalene (9) are temperature dependent, displaying two singlets that collapse in a sharp singlet about 100°C. Although the two conformers of 5, 7, and 9 can be detected in solution, only the most stable of each pair, at least in the case of 7, is present in solid form (X-ray analysis). A dynamic 1H NMR study shows that the barriers to rotation of CHCl2, CHBrCl, and CHBr2 groups in 5, 9, and 7 are as high as 16.8, 18.2, and 19.3 kcal mol−1, respectively. The X-ray structure of 7 is commented, and spectral data of the synthesized compounds are reported.

The chlorination of 2-methylnaphthalene (1) and 1-methylnaphthalene (12) by means of Silberrad's reagent (initial components: SO 2 Cl 2 , S 2 Cl 2 , and AlCl 3 ) has been performed.We describe our results concerning the synthesis of the two heptachloro(chloromethyl)naphthalenes and the Friedel-Crafts alkylation of pentachlorobenzene

Bis(pentachlorophenyl) silanediol (3) has been prepared by neutral hydrolysis of perchlorodiphenylsilane (2). Reduction of 2 with LiAlH4 gives bis(pentachlorophenyl) silane (4) which upon treatment with bromine gives dibromobis(pentachlorophenyl)silane (5). Reaction of 2 with methanol and ethanol leads to dimethoxybis(pentachlorophenyl)silane (6) and diethoxybis(pentachlorophenyl)silane (7) respectively. The IR spectra of 2-7, as well as the UV and 1H NMR spectra of some of these compounds, are reported. The results of thermogravimetric and differential scanning calorimetric studies on silanediol 3 are discussed. The structure of the silane 7 has been established by X-ray crystallography. © 1992.

CCl 3 F in the presence of AlCl 3 is not only a very suitable reagent for the trifluoromethylation of polychlorobenzenes, but also for converting CCl 3 group into CF 3 group, at least in the cases of perchlorotoluene and 2,4,5-trichloro-1-(trichloromethyl)-benzene

5 pages, 4 figures, 2 tables.-- Available online Jan 11, 2006., There is a difference in structure across the wool fibre which is usually referred to as bilateral. The endothermic denaturation doublet of keratins has been observed by different authors for a variety of keratins and measuring conditions and mainly interpreted by different theories. Merino wool yarns have been analyzed by the thermomechanical analysis and at low stress two thermal transitions before melting have been identified. These two thermal transitions are in accordance with the onset temperatures of the denaturation doublet shown by the DSC both at temperatures lower than the thermal degradation temperature determined by TG. The DSC of fibrillated fibres by abrasion showed not a denaturation doublet but just only a denaturation peak. The two transitions of the TMA and the modification of the DSC curve by abrasion seems to confirm that abrasion removes the component which denaturates at lower temperature., Authors are indebted the Spanish Ministry of Science and Education for its financial help through the Project MAT2004-04981-C03-03.

7 pages, 3 figures, 4 tables.-- Printed version published May 2003., The differential sdlubility and thermal analysis of three kinds of polyester fibers designed for rotor, worsted ring, and carded ring spinning are measured. Poly(ethylene terephthalate) yarns are obtained through the three processes and then analyzed. Using a thermomechanical analyzer, the thermal transitions of the different yarn types are determined. The crystallinity of fibers and yarns is measured by DSC. The relationship between thermal transitions, crystallinity, and differential solubility of the polyester fibers and yarns is studied and some inferences on its fine structure are reported., Financial support through the 2001 Industry-CSIC (Departamento de Postgrado y Especialización) Postdoctoral Grant.

Several polycloro(trifluoromethyl)benzenes have been prepared by treatment of the corresponding polychlorobenzenes with CCl3F and AlCl3. The resulting trifluoromethyl derivatives, by reaction with the same inorganic halide in CS2, give their trichloromethyl analogues.

Several polycloro(trifluoromethyl)benzenes have been prepared by treatment of the corresponding polychlorobenzenes with CCl3F and AlCl3. The resulting trifluoromethyl derivatives, by reaction with the same inorganic halide in CS2, give their trichloromethyl analogues.

The sulfonations of pentachlorobenzene (1) with 25% oleum at 40°C or 140°C, or with 65% oleum at 40°C give always excellent yields of pentachlorobenzenesulfonic anhydride (2). However, pentachlorobenzenesulfonic acid (3) is obtained when the working up of the reaction mixture is not mild enough to avoid the hydrolysis of the anhydride 2. Acid 3 is also synthesized starting from pentachlorophenol (4) via O-pentachlorophenyl dimethylthiocarbamate (6), its isomerization to S-pentachlorophenyl dimethylthiocarbamate (7) and final oxidation to 3. Pentachlorobenzenesulfonyl chloride (8) and anhydride (2) are also obtained from acid 3. Anhydride 2 reacts at 200°C with phenol 4 or pentachloroaniline (10) giving pentachlorophenyl pentachlorobenzenesulfonate (9), or a mixture of pentachlorobenzenesulfonyl pentachloroanilide (11) and pentachloroanilinium pentachlorobenzenesulfonate (12), respectively. Sulfonamide 11 can be obtained in two polymorphic forms and an ethyl ether solvate, for which interesting sp...

The sulfonations of pentachlorobenzene (1) with 25% oleum at 40°C or 140°C, or with 65% oleum at 40°C give always excellent yields of pentachlorobenzenesulfonic anhydride (2). However, pentachlorobenzenesulfonic acid (3) is obtained when the working up of the reaction mixture is not mild enough to avoid the hydrolysis of the anhydride 2. Acid 3 is also synthesized starting from pentachlorophenol (4) via O-pentachlorophenyl dimethylthiocarbamate (6), its isomerization to S-pentachlorophenyl dimethylthiocarbamate (7) and final oxidation to 3. Pentachlorobenzenesulfonyl chloride (8) and anhydride (2) are also obtained from acid 3. Anhydride 2 reacts at 200°C with phenol 4 or pentachloroaniline (10) giving pentachlorophenyl pentachlorobenzenesulfonate (9), or a mixture of pentachlorobenzenesulfonyl pentachloroanilide (11) and pentachloroanilinium pentachlorobenzenesulfonate (12), respectively. Sulfonamide 11 can be obtained in two polymorphic forms and an ethyl ether solvate, for which interesting sp...

The synthesis, characterization, and physical properties of perchloro-2,6-bis(diphenylmethyl)-pyridine-α,α'-ylene biradical (1) and αH-tricosachloro-2,6-bis(diphenylmethyl)pyridine-α'-yl radical (2) which present exceptionally high stabilities are reported. The synthesis of 1 and 2 have been accomplished using different strategies in order to get them separately, although 1 always contains 2 as an impurity. 1 is a molecule constituted by two trivalent carbon atoms linked by a trichlorom-pyridylene spacer which has proved to be a good ferromagnetic coupling unit. Magnetic susceptibility measurements from 4.2 to 300 K show that the ground state of 1 is the triplet being 2J=358±14 cm -1 (1.03 kcal/mol), the triplet-singlet energy gap. At low temperature, an antiferromagnetic interaction between intermolecular spines was observed (Curie temperature, θ 1 =-2.02±0.10K). The EPR spectrum of 1 in frozen 2-methyltetrahydrofuran (133 K) in the Δm s =±1 region affords three symmetric pairs of lines corresponding to a triplet species without axial symmetry with zfs parameters |D/hc|=0.0081 cm -1 . The Δm s =±2 transition follows the Curie law over the range 10.0-62.o K, supporting the highest multiplicity of the molecule in the ground state. The cyclic voltammogramm of 1 exhibits a redox couple (E°=0.18 V vs SCE) which is attributed to the reduction of this biradical to the stable anion 12 (1 - ), and a second irreversible peak (E p c = -0.25 V vs SCE) which is ascribed to the formation of the unstable dianion 13 (1 2- ). The electronic spectrum of 1 is presented and discussed

A partially oriented melt-extruded PLA multifilament was false-twist textured to stabilize its structure. Conventional DSC analysis showed a relaxation peak at the end of glass transition. Simultaneous consideration of the TMA curve enabled us to evaluate both the relaxation and the cold crystallisation produced during the DSC scan. The periodic load applied during TMA experiments also enabled us to examine the evolution of Young’s modulus along the glass transition, relaxation and cold crystallisation phenomena. Increases in Young’s modulus and in enthalpy are related because of crystallisation. Texturing increased crystallinity and decreased cold crystallisation of PLA during the DSC scan.