Effect of wool keratin proteins and peptides on hair water sorption kinetics

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.     

Effect of the Presence of an Ester of Montanic Acids With Multifunctional Alcohols in the Composites of Titanium Dioxide Nanoparticles With Poly (Ethylene Terephthalate) in Their Non-Isothermal Crystallization

The effect of the addition of an ester of montanic acid with multifunctional alcohols in the effectiveness of the dispersion and compatibility of TiO₂ nanoparticles when included as filler in poly(ethyleneterephthalate) for composite production is studied through the study of the non-isothermal crystallization by differential scanning calorimetry (DSC). The application of the Avrami method enables to evaluate the compatibility and the level of dispersion/aggregation of the nanofiller in the poly(ethyleneterephthalate) by the analysis of the temperature and enthalpy of crystallization, the kinetic parameters and the half-crystallization time.     

Water sorption of nails treated with wool keratin proteins and peptides

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.     

Thermal transitions of polylactide false-twist textured multifilaments determined by DSC and TMA

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.     

Thermomechanical analysis of merino wool yarns

Summary 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.     

The effect of internal lipids on the water sorption kinetics of keratinised tissues

Water has a large influence on the properties of keratinised tissues. The water diffusion properties of keratinised tissues are known to be governed by the cell membrane complex, which is mainly composed of internal lipids. The main aim of this work was to characterise the differences in the water sorption and desorption behaviour of human hair and stratum corneum (SC) both with and without internal lipids. Absorption and desorption curves were obtained using a thermogravimetric balance equipped with a controlled humidity chamber. The results demonstrate that the role of the intercellular lipids in the SC is more marked than in hair, which is likely due to the greater amount of lipids present in its structure. Therefore, lipid structures in the SC are essential both to prevent changes in the water-holding capacity of the skin and to maintain the water permeability of the SC.     

Effect of the air-jet and the false-twist texturing processes on the thermomechanical behaviour of polyamide 6.6 yarns

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.     

Effect of different dispersing agents in the non-isothermal kinetics and thermomechanical behavior of PET/TiO2 composites

This work is based on the analysis of the influence of dispersing agents on the non-isothermal kinetics, thermomechanical behavior and dispersing action of PET/TiO₂ nanocomposites. The influence of two montanic waxes and an amide wax used as dispersing agents in the nucleating effect of the nanoparticles is studied. The dispersing agents are the following: a) a partly saponified ester of montanic acids (PSEMA), b) an ester of montanic acids with multifunctional alcohols (MAWMA) and c) an amide wax based on N,N′-Bisstearoyl ethylenediamine (AW). The non-isothermal kinetics based on the Avrami method revealed that MAWMA and PSEMA favors the nucleating effect of the nanoparticles when are included in PET. Birefringence microscopy points out the good dispersing capacity of MAWMA and AW and the termomechanical analysis confirmed that the ester of montanic acids with multifunctional alcohols MAWMA shows the best dispersing properties and best promotes the nucleating effect of the TiO₂ nanoparticles when used for PET/TiO₂ nanocomposites production.     

Determination of the heatsetting temperature of polyester by TMA

The determination of the effective temperature of the thermal treatment applied to polyester substrates in the textile process has been broadly studied by differential scanning calorimetry (DSC). In this investigation, the authors have studied the possibilities of the thermomechanical analysis (TMA) as a method for the determination of this temperature. For this purpose, fabrics of polyester heatset in an industrial plant between 160 and 210°C, have been analyzed by DSC and TMA. The good results obtained show the possibilities of this technique for the determination of the effective temperature of a thermal treatment. This revised version was published online in July 2006 with corrections to the Cover Date.