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Tammann&rsquo, s two-stage crystal-nuclei-development method is applied for analysis of the thermal stability of homogenously formed crystal nuclei of poly(butylene isophthalate) (PBI) as well as their possible reorganization on transferring them to the growth temperature, using fast scanning chip calorimetry. Crystal nuclei were formed at 50 &deg, C, that is, at a temperature only slightly higher than the glass transition temperature, and developed to crystals within a pre-defined time at the growth temperature of 85 &deg, C. The number of nuclei, overcritical at the growth temperature, was detected as a function of the transfer-conditions (maximum temperature, heating rate) by evaluation of the developed crystal fraction. For different size-distributions of crystal nuclei, as controlled by the nucleation time, there is detected distinct reduction of the nuclei number on heating to maximum temperatures higher than about 90 to 110 &deg, C, with the latter value holding for longer nucleation time. Longer nucleation allows for both increasing the absolute nuclei number and generation of an increased fraction of larger nuclei. Heating at 1000 K/s to 140&ndash, 150 &deg, C causes &ldquo, melting&rdquo, of even the most stable nuclei. While direct transfer of crystal nuclei from the nucleation temperature (50 &deg, C) to the growth temperature (85 &deg, C) reveals negligible effect of the transfer-heating rate, in-between heating to higher temperatures is connected with distinct nuclei-reorganization above 85 &deg, C on heating slower than 1000&ndash, 10.000 K/s. The performed study not only provides specific valuable information about the thermal characteristics of crystal nuclei of PBI but also highlights the importance of proper design of Tammann&rsquo, s nuclei development experiment for analysis of nuclei numbers. With the evaluation of critical rates of temperature-change for suppression of non-isothermal formation of both nuclei and crystals, the kinetics of crystallization of the slow crystallizing PBI is further quantified.

9th International Conference on Broadband Dielectric Spectroscopy and its Applications; University of Pisa and National Research Council, Pisa, Italy; September 11-16, 2016; http://the-dielectric-society.org/?q=9th-bds-conference-pisa-2016, Due to the limited availability of fossil sources and their price fluctuations, the current interest of both academic and industrial communities is nowaday focused on the development of polymeric materials from renewable resources. Among the so-called green chemicals, 2,5-furandicarboxylic acid displays a large potential as green monomer for the synthesis of new polyesters able to replace the very important thermoplastic polymers based on petroleum-derived terephthalic acid, from which differ for the substitution of the benzene ring with a furanic one. 1,4-cyclohexanedicarboxylic acid is also a biobased monomer, whose polyesters proved to be biodegradable. The presence of an aliphatic ring permits conformational isomery, not possible for the aromatic ring, which strongly influences the final properties. Lastly, 1,3-propanediol can be also obtained by renewable feedstocks. Taking into account this scenario, poly(propylene 2,5-furanoate) (PPF) and poly(propylene 1,4-cyclohexanedicarboxylate) (PPCE) have been synthesized and the structure-dynamics relationship has been investigated by means of dielectric loss spectroscopy, focusing the attention on sub-glass relaxations. The two new biobased polyesters have been then compared with the well-known poly(propylene terephthalate) polyester (PPT) previously investigated, in order to evaluate the effect of substitution of the aromatic ring of PPT with the aliphatic ring of PPCE, on one side, and with the furanic ring of PPF, on the other side. The corresponding polyesters of neopentyl glycol have been also prepared and taken into consideration. In fact, as previously pointed out in the case of terephthalic-based polyesters , the substitution of the two hydrogen atoms of the methylene group in B position with respect the ester oxygen with methyl groups renders the mcromolecular chains stiffer and consequently significantly impacts on sample dynamics.