Structure formation in poly(ethylene terephthalate) upon annealing as revealed by microindentation hardness and X-ray scattering

Abstract The micromechanical properties (microindentation hardness, H, elastic modulus, E) of poly(ethylene terephthalate) (PET), isothermally crystallized at various temperatures (T a ) from the glassy state are determined to establish correlations with thermal properties and nanostructure. Analysis of melting temperature and crystal thickness derived from the interface distribution function analysis of SAXS data reveals that for T a !190 8C the occurrence of two lamellar stack populations prevails whereas for samples annealed at T a O190 8C a population of lamellar stacks with a unimodal thickness distribution emerges. The H and E-values exhibit a tendency to increase with the degree of crystallinity. The results support a correlation E/Hw20 in accordance with other previously reported data. The changes of microhardness with annealing temperature are discussed in terms of the crystallinity and crystalline lamellar thickness variation. Unusually high hardness values obtained for PET samples crystallized at T a Z190 8C are discussed in terms of the role of the rigid amorphous phase which offers for the hardness of amorphous layers constrained between lamellar stacks a value of H a w150 MPa. On the other hand, for T a Z 240 8C the decreasing H-tendency could be connected with the chemical degradation of the material at high temperature.

One possible explanation for the α* relation in non-crystalline materials

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43032/1/10855_2004_Article_BF00719868.pd

Real-time WAXS study of induced orientation in a liquid crystalline polyester under the influence of a magnetic field

Developed in the context of SAFmaps, containing a georeferenced database on ethanol distilleries, ethanol pipelines and terminals, oil refineries authorized for the production of aviation kerosene and soy processing plants, in Brazil. For ethanol distilleries, the information includes: identification, place, feedstock, products (ethanol/sugar/mix), sugarcane milling capacity (2020), the installed capacity of anhydrous and hydrated ethanol production (2020), and effective production of anhydrous and hydrated ethanol (2019-2020). Ethanol units are registered by ANP. Terminals of the ethanol pipeline system and ethanol pipelines that compose the multimodal logistic system developed by Logum Logística S.A. are made available. For oil refineries, the information includes: identification, place, refining capacity, aviation kerosene and oil processed in 2019 For soy processing plants, the information includes: identification, place, and the status (In operation/Not in operation) in 2018. SAFmaps is a database platform with information on the potential of promising feedstock for the production of Sustainable Aviation Fuels (SAF) in Brazil. SAFmaps includes a database of different feedstocks, background information and assessment results