Challenges in the experimental investigation of the caloric and thermomechanical behaviour of semi-crystalline polymers: A study on the example of polyethylene terephthalate (PET)

Publication date: Available online 7 December 2019Source: Polymer TestingAuthor(s): C. Mittermeier, A. LionAbstractInvestigations on industrial produced polyethylene terephthalate (PET) were carried out in the temperature range from the glassy to the liquid state. In differential scanning calorimetry (DSC) experiments, the sample passed through this temperature range several times at different speeds, interrupted by isothermal segments. Thereby the caloric behaviour observed in earlier publications could be confirmed. A closer look reveals variations in the behaviour, depending on the initial state of the sample. The thermal and mechanical boundary conditions seem to have a long-term influence on the semi-crystalline state. Independent of the initial state, a fundamental decrease in the crystallization tendency could be observed after each temperature loop. The most likely explanation for that is an increase in molecular weight in the higher temperature ranges. This leads to an increase in viscosity, as it occurs in the solid poly-condensation (SSP) process. Mechanical experiments were also carried out in the temperature range investigated, but only at different isothermal levels due to experimental limits. For these experiments, theoretical considerations were made on the basis of the viscoelastic generalisation of Hooke’s law. These show the influence of the significant decrease of the ratio between shear- and bulk stiffness in the glass-transition range. While the un...
Source: Polymer Testing - Category: Chemistry Source Type: research

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In this study, we first designed and prepared a novel multi-functional photoluminescence form-stable phase change materials (FSPCMs) using photoluminescence side chain liquid crystalline polymers with different flexible spacers length as gelators, and using paraffin as phase change materials. The properties, and the effect of flexible spacer length on the properties of photoluminescence FSPCMs were studied in detail by “tube test” method, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), fourier-transform infrared spectroscopy (FT-IR), polarized optical microscopy (POM), rheometry test,...
Source: Polymer - Category: Chemistry Source Type: research
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Source: Scandinavian Journal of Primary Health Care - Category: Primary Care Authors: Source Type: research
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Source: Psychopharmacology - Category: Psychiatry Source Type: research
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Source: Fluids and Barriers of the CNS - Category: Neuroscience Source Type: research
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Publication date: Available online 20 January 2020Source: Materials Science and Engineering: AAuthor(s): K. Korgiopoulos, M. PekguleryuzAbstractIt was observed that low level of yttrium (Y) has a modifying effect on the Mg17Al12 phase in the binary Mg-6wt%Al casting alloy. Scanning/transmission electron microscopy, mechanical testing and thermodynamic calculations were employed to understand the modification mechanism. It is found that Y at trace level refines the β-Mg17Al12 phase leading to increased tensile elongation and compressive strain to fracture. The refinement effect is lost with further increase in the Y le...
Source: Materials Science and Engineering: A - Category: Materials Science Source Type: research
Cancer Research UK scientists working in Cambridge made a vital energy-producing chemical magnetic and used MRI scans to watch how quickly breast cancer cells used it up.
Source: the Mail online | Health - Category: Consumer Health News Source Type: news
The J.P. Morgan Healthcare conference runs every year in San Francisco, a big draw for the biotech industry, and many organizations take the opportunity to host events at the same time. Among these, the SENS Research Foundation has for the past few years hosted a pitch day in which biotech companies in the longevity industry, largely startups, present to that portion of the Bay Area investor community interested in funding the treatment of aging as a medical condition. I was there to present on progress at Repair Biotechnologies, and took some notes on the other companies as they talked about their work. Kimera Labs ...
Source: Fight Aging! - Category: Research Authors: Tags: Investment Source Type: blogs
Publication date: Available online 20 January 2020Source: Food HydrocolloidsAuthor(s): Yuying Wang, Anqi Zhang, Xibo Wang, Ning Xu, Lianzhou JiangAbstractFor the first time, the irradiation technology combined with Maillard reaction were used to improve the freeze - thaw stability of soybean protein emulsion. The freeze-thaw stability of emulsions prepared with soy protein isolate (SPI), soy protein isolate and maltose mixture (SPI+M) or glycosylated soy protein isolate with maltose formed by irradiation of 7.5 kGy and 12.5 kGy (named SPI-M7.5 and SPI-M12.5, respectively) was compared. Fourier transform infrared spectrosco...
Source: Food Hydrocolloids - Category: Food Science Source Type: research
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Source: Food Hydrocolloids - Category: Food Science Source Type: research
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