Polylactide Used as Filment in 3d Printing – Part 2: TG-DTG, DSC and DRIFT investigations

A series of structural and thermal analysis research (TG-DTG, DSC, DRIFT) were performed for the samples of polylactide (PLA), which is commonly used in additive technologies as a structural material. In total four materials were considered, including two containing dyes with different colors, a material made of PLA recyclate and a graphene-modified PLA material. It was noted that PLA material reinforced with graphene phase (GRAFYLON®) retains the best thermal properties (TG-DTG), which results in wider possibilities of its processing, including further modification and usability in manufacturing vehicle structural elements. Recycled PLA material (ALFA+W) was characterized by a higher melting point (Tp) by more than 20oC than other samples (DSC analysis), so it can be more useful in the production of structural elements operating, as well as used at elevated temperatures

FT-IR STUDIES OF THE POLYMERIC BINDER BioCo1 WITH MODIFIED BIOPOLYMER – PART I

The paper presents structural studies of polymeric water soluble compositions consisting of acrylic derivatives/modified biopolymer. The research FT-IR was focused on novel polymer composition poly(acrylic acid)/modified starch (PAA/CMS) designed for application in the foundry industry - a novel group of polymeric BioCo binders. It was found, that the structure changes occur within groups: carboxyl present in poly(acrylic acid) and carboxyl and hydroxyl groups contained in carboxymethyl starch (vibrations: νs-C=O, νs-COO- and δ-C-O-H). 

"Granice i pogranicza: państw, grup, dyskursów... : perspektywa antropologiczna i socjologiczna" - recenzja

Praca zbiorowa Granice i pogranicza: państw, grup, dyskursów… Perspektywa antropologiczna i socjologiczna, przygotowana pod redakcją naukową Grażyny Kubicy i Haliny Rusek, zawiera teksty badaczek i badaczy związanych z Sekcją Antropologii Społecznej Polskiego Towarzystwa Socjologicznego. Jak piszą Redaktorki we Wprowadzeniu, intencją autorów była reinterpretacja teorii granic Frederika Bartha w kontekście granic państwowych, kulturowych, granic tworzonych między dyscyplinami, dyskursami, ale i klasami. Opracowanie składa się z trzech części i zawiera szesnaście artykułów, w których autorzy podejmują problematykę granic i pograniczy w szerokim kontekście kultury

Coming Back from International Educational Exchanges – Difficulties, Changes, Challenges

International collaboration in education has resulted in an increasing number of participants in educational exchanges at various stages of education. Taking part in a foreign intercultural exchange is an important experience, associated with a half a year or a year-long immersion in another culture and with the return home. Changing the residence country for a certain period, learners consciously undertake the tasks aimed at familiarization with the new culture, language, customs or behaviours. Few of them think about the difficulties associated with the comeback. The presented research results show that, during the exchange, learners were able to build their strategy of functioning in the host family and country. As a result, this helped them to handle the difficulties of the reverse culture shock, which is manifested by the optimistic-active strategy applied by most of the learners after returning home

BIODEGRADATION OF A NEW POLYMER BINDER BASED ON MODIFIED STARCH IN A WATER ENVIRONMENT

In this study, the results of biodegradability of new polymeric binder consist of modified starch - Polvitex Z (by Xenon) in water solution are presented. Biodegradation tests were conducted in accordance with Zahn-Wellens method, which is intended to denote the susceptibility to biodegradation by microorganisms (in high concentrations during the static test) of the non-volatile, watersoluble organic compounds. Observations of the decomposition process was carried out through regular, daily or at certain time intervals by measurement the Chemical Oxygen Demand (COD) and level of biodegradability (RT)  in the prepared samples during the test. The study showed that the starch binder is fully biodegradable material in an aqueous medium.

Polylactide Used as Filment in 3D Printing – Part 1: FTIR, DRIFT and TG-DTG Studies

A short literature review was undertaken in terms of the structure, properties and applications of polymers, including those commonly used in 3D printing. The research part included the structural and thermal analysis of polylactide (PLA), which is an example of an extensively used polymer in the developing 3D technology. Special attention was paid to the comparison of structure and thermal stability of two different (from various producers) polylactide samples. The research, involving such analytical methods as infrared spectroscopy (FTIR) and diffuse reflectance infrared spectroscopy (DRIFT), allowed the comparison of the structure of the two PLA samples considered. The determination of the temperature range in which changes related to PLA thermodestruction occur was a result of the performed thermoanalytical research (DRIFT, TG-DTG). Thermal studies also allowed to establish the temperature range in which the material does not yet degrade, which is important in the context of future planned research work on polylactide modification to obtain the improvement of the thermal and mechanical properties of PLA-based materials. This research area will be described in the second part of the publication

DETECTION OF NITRATES(V) AND SULFATES(VI) BY UV-VIS SPECTROPHOTOMETRY METHOD IN USED GREEN SAND BONDED BY BENTONITE WITH MODIFIED STARCH ADDITION

The research results (SEM, UV-Vis) that contain a part of the work connected with determining the influence of a modified starch addition on the physical and chemical property changes of green sands (including the emission levels of harmful substances from the used molding sands formed as a result of the liquid metal pouring of molds) are presented in this paper. A surface analysis (SEM) was performed for the fresh molding sands and used molding sands with and without modified starch samples. On the bases of the received microscopic images, the impact of the temperature factor on the morphology of the molding sand samples after the liquid metal pouring process are assessed. In the second part of the performed work on the UV-Vis research, eluates from two used molding sands (green sand [sand number 1] and green sand with the addition of a modified starch [sand number 2]) were tested for nitrate and sulfate content. In order to determine whether the level of nitrate and sulfate elusion from the used molding sands is permissible, the received results were compared with the Minister of Environment’s regulations concerning the requirements of surface waters used for supplying the population with potable water

STRUCTURAL CONSTRUCTION OF THE HARDENERS WITH DIFFERENT HARDENING RATES INTENDED FOR GEOPOLIMER BINDER SYSTEMS USED FOR THE PREPARATION OF MOULDING SANDS

The paper presents the results of structural investigations of hardeners series of different hardening rate of the geopolymer Geopol, manufactured by the Sand-Team Company. Studies showed that these hardeners have the similar chemical structure and that the hardening rate of the binder depends on the proper selection of the proportions of respective components

THE RECLAMATION OF SPENT SAND BONDED BY POLYMERIC BINDER BioCo2

The paper presents the results of studies on reclamation of moulding sand with a new polymeric binder BioCo2. The polymeric binder of new generation – BioCo2 – is an aqueous solution of two-component polymeric composition of poly(acrylic acid) and dextrin. The aim of research was to show whether can recover sand (reclaim) from the used sand. The properties for reuse as a component of moulding sand were discussed.Used sands and reclaim were subjected to analysis designed to show the degree of reclaimability. Assessment of process was based on the following indicators: the amount of dust released during reclamation, loss on ignition, WSR index and the surface morphology of the sand grains

BTEX EMISSIONS FROM BioCo2 BONDED MOULDING SANDS

The aim of the research was to determine the volume of BTEX emission (benzene, toluene, ethylbenzene and xylenes) from BioCo2 bonded moulding sands. BioCo2, a new polymer binder, is a water solution of two - component polymer composition(polyacrylic acid and dextrin).Research on gas emissions were performed according to the method developed at Faculty of Foundry Engineering, AGH University of Science and Technology. The measurementof BTEX samples adsorbed on activated carbon was made with the use of gas chromatography (GC-FID) and was followed by a qualitative and quantitative analysis. The research showed that the volume of BTEX emissions was lower in BioCo2 bonded moulding sand than in resin-bonded sand Kaltharz U404