Teresa Nuño

Kinetics of mono alkyl itaconates bulk polymerization by DTA

Abstract The kinetics of mono alkyl itaconates (methyl, ethyl and propyl) bulk self-initiated polymerization were determined by DTA in the temperature range 428–458 K and in the presence of 1,2-azobisisobutyronitrile in the temperature range 363–403 K. The polymerization reaction orders, and the activation energies E a were found to depend on the itaconate nature as well as the enthalpies involved in these processes.

Kinetics of methacrylic derivates bulk polymerization by DTA: Study of the influence of the monomer side group

Abstract The kinetics of a set of methacrylates (t-butylphenyl methacrylate, 2,6-diisopropylphenyl methacrylate and 4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate) bulk self-initiated polymerization were determined by DTA in the temperature range 413–493 K, and in the presence of 1,2-azobisisobutyronitrile in the temperature range 373–453 K. The polymerization reaction orders, and the activation energies E a were found to be dependent on the nature of the methacrylate side group as well as on the enthalpies involved in these processes. The influence of the monomer side group on the polymerization process is discussed.

Bulk polymerization kinetics of methacrylic dimethyl amino ethyl ester acid by DTA

Abstract The kinetics of methacrylic dimethyl amino ethyl ester acid bulk polymerization in the temperature range 428–438 K were determined by differential thermal analysis (DTA). The polymerization reaction of this compound was found to be of first order with respect to the monomer. The values of overall activation energy, E A , as well as the pre-exponential factor, B , were calculated.

Young children’s environmental judgement and its relationship with their understanding of the concept of living things

Abstract Do young children think that plants deserve morally-based respect or, on the contrary, do they feel that respect for plant life is nothing more than another behavioural norm similar to, for instance, one that states that you should not pick your nose in public? This study examines how dilemmas involving environmental, moral and socio-conventional situations are comprehended in early childhood so as to investigate the issue of whether young children attach a significant degree of severity to transgressions against plant life in comparison with disregarding socially accepted rules. Additionally, young children’s judgements are put into perspective alongside their understanding of the concept of living things in order to shed light on the role that grasping essential biological notions might play in the emergence of young children’s assessments of actions that pose a threat to the environment. The sample of the study consists of 328 children (162 girls and 166 boys) who attend Early Years Education or Primary Education and the data examined comes from the individual interviews conducted with the children. The results are discussed in connection with the current understanding of the source of ethical judgements which emphasises the importance that emotions seem to play in the construction of moral thinking.

Free-radical bulk polymerization kinetics of 1-vinyl-imidazole at total conversion by DTA

Abstract The free-radical polymerization of 1-vinyl-imidazole at total conversion in the temperature range 363 to 433 K has been studied by differential thermal calorimetry (DTA). From the experimental data the kinetic order has been calculated and a change in the order has been found in the temperature interval 363–393 K. At higher temperatures the kinetic order remains constant. In order to explain this change we have proposed a kinetic scheme. Finally, the activation energy, EA, and the pre-exponential factor, A, are calculated using the Arrhenius equation.

Young children’s understanding of plant life: a study exploring rural–urban differences in their drawings

Abstract Drawing activities are believed to be a useful methodology to gain insight into young children’s thoughts and ideas related to a diverse range of research topics. In this respect, the study of drawings has proven to be a valuable procedure with a view to unravelling how the natural world is conceptualised in early childhood. The present study examines the content of the drawings that 328 Spanish children aged between of 4 and 7 carried out in their bid to express their understanding of plant life and the data collected is related to the potential for connecting with nature which may be offered by the location of their educational centres. The results show slight but significant differences between the depictions undertaken by the children attending schools in rural environments, and those made by their peer group in urban centres. The evidence and conclusions of the study are coherent with the assumption that as early as kindergarten age, children are well involved in attempting to give meaning to their nature-based experiences.

Polymerization of 4-vinyl biphenyl at advanced degrees of conversion

The bulk self-initiated polymerization kinetics, assuming total conversion, of the 4-vinyl biphenyl was determined by differential thermal analysis (DTA) in the temperature range 463–533 K. Likewise, the overall activation energy, Ea, and the polymerization enthalpies involved in the process have been calculated, as well as the overall rate constants and the reaction order with respect to the monomer concentration.