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Copyright of Ciencia, Tecnología y Salud is the property of Ciencia, Tecnologia y Salud and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bistua: Revista de la Facultad de Ciencias Básicas is the property of Facultad de Ciencias Basicas de la Universidad de Pamplona and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper we studied the physico-chemical, thermal and mechanical properties of the Mopa Mopa (MM) resin, also known as varnish Pasto, obtained it from the leaf bud of the elaegia pastoensis Mora tree. The extraction process of the material is carried out by a hot leach, using ethanol as solvent. Using the MM resin the previously obtained, were prepared test specimens using a process of hot compression molding using a heating plate press. The samples were dried at 80°C for 24 hours and then conditioned at three different relative humidities (R.H.) (47 ± 2%, 77 ± 2% and 97 ± 2%). Thermogravimetric analysis (TGA) in the MM resin revealed that the material showed thermal stability up to about 230°C, indicating that it is feasible to transform it by a thermal process. Later, tests Differential Scanning Calorimetry (DSC) was established that the MM resin had some degree of semi-crystallinity. Finally, moisture absorption and the mechanical properties presented were directly proportional to the different R.H. used on the preparation. [ABSTRACT FROM AUTHOR]

In this work, the experimental design of Taguchi model was applied in order to obtain the most appropriate parameters to elaborate an agglomerate material which presents a good mechanical and thermal behavior. The raw materials used were rice husk, common clay, sand and aloe gel. The importance of the development of the synthetic agglomerates is in the use of agricultural wastes to give them an useful employment when replacing materials of great demand. The experimental combinations were done varying the control factors values: rice husk percentage (R), temperature (T) and thermal treatment time(t). Via to the optimization properties according Taguchi's Methodology, the elasticity modulus, the absorbed energy in the impact, break maximum module and initial decomposition temperature to each experimental combination were selected. The Qualitek-4 software was used below the biggest the better quality characteristic. The optimum parameters obtained to each control level were: R = 15%, T = 120°C and t = 3 h. These results were confirmed with a new experiment, where similar properties to the wood species were obtained. The developing of this will be useful as substitute of the wood and could improve the environment impact due residual materials. [ABSTRACT FROM AUTHOR]

The efficiency of heat stabilizers based on Ca-Zn metal can be increased by up to 50% when it is added hydrotalcite. This paper compares results of thermal stability, measured by two methods: static (conductivity) and dynamic (with a torque rheometer) - to determine differences in the efficiency of three commercial grades of hydrotalcite formulated at different doses. Additionally, limitations for the ISO 182-3 method are identified for evaluating the thermal stability Ca-Zn compounds and an empirical model that relates DHC thermal stability (static) and the Ca / Zn stabilizer system based metals is proposed. [ABSTRACT FROM AUTHOR]