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The present review showed the importance of using the differential scanning calorimetry (DSC) in the evaluation of the hair damage. Many hair-straightening treatments necessarily involve a heating process, which even at low temperatures can cause damage to hair. Several researches demonstrated the influence of the exposure to heat in various types of hair, correlating it with the increase in the temperature. In this sense, the importance of this research is in raising awareness to the consumers and professionals (cosmetic formulators, researchers, hair stylists and dermatologists) about the issues of employing heat in the modification of the hair. To this, the present review refers to a broad and updated bibliographic collection comprising several studies related to the investigation of the thermal events that occur in the hair under heating until 300 °C, including the denaturation of the α-keratin, employing DSC. This protein forms a crystalline structure in the hair cortex and provides the hair mechanical properties such as strength and elasticity. But once denatured, the damage done to the hair may be irreversible. However, studies related to thermal decomposition of this protein are necessary due to the increased use of thermal hair styling tools, which can be associated, or not, with chemical treatments. Yet, in the literature, few reviews on this important tool of characterization and evaluation in hair samples are available. Thus, additionally, the objective of this work is to support researchers to direct the study with most feasible experimental conditions to achieve more potent results employing DSC. [ABSTRACT FROM AUTHOR]

The wood is considered a natural composite of extreme complexity, mainly composed of cellulose, lignin, hemicellulose (polyposis), and extractives. Its composition encourages biological attacks from different species. In this context, several techniques have been studied and applied for disinfecting and decontaminating wood-made works of art and cultural heritage objects, which have been damaged by fungi, bacteria, and insects. Gamma radiation has been studied as an alternative to chemical methodologies for this purpose. By this way, the aim of this article is to illustrate the effect of gamma radiation on some physicochemical properties of Pinnus patula, Pinnus cunninghamia, Cedrella fissillis, and Ocotea porosa wood species. The irradiation has shown itself to be a fast and efficient process to eliminate infestations by both insects and microorganisms and no quarantine is required because of the no generation of toxic residues. On the other hand, this process does not protect the irradiated material from re-infestations or re-contamination. In this study, relatively high gamma radiation doses were applied up to 100 kGy so that radiation effects, which are cumulative, could be retrieved by means of thermal properties. The results have shown that gamma radiation, in the studied dose range, does not promote meaningful alterations on the evaluated properties, which allows that artifacts be irradiated multiple times, even if a re-infestation occurs. [ABSTRACT FROM AUTHOR]

Plastics have been used in short-life products, which have presented harmful consequences for the nature, because of the low degradation rate reached by the most common polyolefins. This work evaluates the mechanical and thermal properties of pure iPP, plasticized starch (TPS) with biodiesel (TPSBio) or commercial (TPSCom) glycerols, and their blends (iPP/TPSPlas). The addition of TPSPlas caused an increasing on the cristallinity of iPP, mainly for the compositions 90/10 and 80/20, probably due to morphological alterations such as crosslinking, that may have modified the molecular arrangement of the iPP in the presence of glycerol. [ABSTRACT FROM AUTHOR]

Hydrogels, in general, can be used as a compliant surface in prosthesis of human synovial joints due to their biocompatible characteristics. In this work, different hydrogels were prepared from two aqueous solutions of PVAL (15 and 20 mass/mass%) by chemical reactions using citric acid as a cross-linking agent and by electron beam (EB) irradiation with doses from 25 to 100 kGy. The hydrogels were evaluated by their mechanical properties through indentation creep test, thermal properties by differential scanning calorimetry (DSC), and also equilibrium water content (EWC). [ABSTRACT FROM AUTHOR]

Radiation curing is an environmentally-friendly technology. Furthermore, radiation curing is a faster, energy saving and more efficient industrial process than the heat-curable process. One of the most important requirements for the widespread application of UV curable coatings in the coating industry is that they are stable vs. atmospheric degradation. Today's state of the art in oxidative drying and thermosetting coatings is the use of light stabilizers to protect polymers vs. the damage of outdoor exposure. Oxygen has a detrimental effect on the cure response of free radical systems, especially in thin-film coatings. Differential photocalorimetry (photo-DSC) was used to investigate the oxygen effect and the use of light stabilizers on UV curing of photocurable formulations based on acrylate materials. Coating thickness influence was also considered. [ABSTRACT FROM AUTHOR]