Structure characterization and biodegradation rate of poly(ε-caprolactone)/starch blends

The present paper focuses on the effects of blending poly (ε-caprolactone) (PCL) with thermoplastic starch (TPS) on the final biodegradation rate of PCL/TPS blends, emphasizing the type of environment in which biodegradation takes place. The blends were prepared by melt-mixing the components before a two-step processing procedure, which strongly affects the degree of plasticization and therefore the final material morphology, as was detailed in the previous work, was used for the thermoplastic starch. The concentration row of pure PCL over PCL/TPS blends to pure TPS was analyzed for biodegradation in two different environments (compost and soil), as well as from a morphological, thermomechanical, rheological, and mechanical point of view. The morphology of all the samples was studied before and after biodegradation. The biodegradation rate of the materials was expressed as the percentage of carbon mineralization, and significant changes, especially after exposure in soil, were recorded. The crystallinity of the measured samples indicated that the addition of thermoplastic starch has a negligible effect on PCL-crystallization. The blend with 70% of TPS and a co-continuous morphology demonstrated very fast biodegradation, with the initial rate almost identical to pure TPS in both environments while the 30% TPS blend exhibited particle morphology of the starch phase in the PCL matrix, which probably resulted in a dominant effect of the matrix on the biodegradation course. Moreover, some molecular interaction between PCL and TPS, as well as differences in flow and mechanical behavior of the blends, was determined. © Copyright © 2020 Nevoralová, Koutný, Ujčić, Starý, Šerá, Vlková, Šlouf, Fortelný and Kruliš.MH CR [NV15-31269A]; Technology Agency of the CR [TE01020118, TN01000008]; Ministry of Education, Youth and Sports of the CR, program NPU I [POLYMAT LO1507

Influence of chain length on intercalation process of polyvinychloride/clay nanocomposites based on alkyl - amine

Cílem této práce je studovat vliv délky alkylového řetězce na interkalační proces a vlastnosti polymer/jíl nanokompozitů. Do dnešní doby bylo studováno velké množství polymerní systémů, ale malá pozornost je stále věnována polyvinylchlorid/jíl nanokompozitům, ačkoliv polyvinylchorid (PVC) patří mezi nejlépe prostudované polymerní systémy a nabízí široké aplikační možnosti. Přírodní montmorillonit Na-MMT, byl interkalován oktadecylaminem (ODA), dodecylaminem (DDA) a oktylaminem (OA) pomocí ion-dipólové interkalace. Cílem bylo zjistit použitelnost těchto interkalátů pro nanokompozitní materiály. Struktura byla hodnocena na základě RTG a molekulových simulací. Všechny nanokompozitní systémy byly připraveny na KO-hnětiči. Výsledné materiály byly testovány z hlediska odolnosti proti abrazi, mechanických vlastností a tepelně-mechanických vlastností."The aim of this paper is to study the influence of chain length on the intercalation processes and on the properties of polymer/clay nanocomposites. Many polymer/clay nanocomposites have been studied so far. Less attention has been given to PVC/clay nanocomposites, although polyvinylchloride (PVC) is the best known and most widely used vinyl plastic. Natural montmorillonite, Na-MMT, was intercalated with octadecylamine (ODA), dodecylamine (DDA) and octylamine (OA) molecules by ion#dipole intercalation to determine the applicability of these intercalates for nanocomposite materials. The structure was determined by X-ray diffraction and molecular simulation. All polymer samples were prepared in a KO-Kneader in melt conditions. The prepared materials were tested for abrasion resistance, and mechanical and thermo-mechanical properties.

How to make usage of the standardized EuroFlow 8-color protocols possible for instruments of different manufacturers

International audienceA critical component of the EuroFlow standardization of leukemia/lymphoma immunophenotyping is instrument setup. Initially, the EuroFlow consortium developed a step-by-step standard operating protocol for instrument setup of ≥8-color flow cytometers that were available in 2006, when the EuroFlow activities started. Currently, there are 14 instruments from 9 manufacturers capable of 3-laser excitation and ≥8 color measurements. The specific adaptations required in the instrument set-up to enable them to acquire the standardized 8-color EuroFlow protocols are described here. Overall, all 14 instruments can be fitted with similar violet, blue and red lasers for simultaneous measurements of ≥8 fluorescent dyes. Since individual instruments differ both on their dynamic range (scale) and emission filters, it is not accurate to simply recalculate the target values to different scale, but adjustment of PMT voltages to a given emission filter and fluorochrome, is essential. For this purpose, EuroFlow has developed an approach using Type IIB (spectrally matching) particles to set-up standardized and fully comparable fluorescence measurements, in instruments from different manufacturers, as demonstrated here for the FACSCanto II, and Navios and MACSQuant flow cytometers. Data acquired after such adjustment on any of the tested cytometry platforms could be fully superimposed and therefore analyzed together. The proposed approach can be used to derive target values for any combination of spectrally distinct fluorochromes and any distinct emission filter of any new flow cytometry platform, which enables the measurement of the 8-color EuroFlow panels in a standardized way, by creating superimposable datafiles