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Influence of the Structure of Low MolecularWeight Esters on Poly(lactic acid) in the Plasticization Process - part 1

Gzyra-Jagieła Karolina, Sulak Konrad, Draczyński Zbigniew, Madej Kiełbik Longina, Jagodzińska Sylwia, Borkowski Dominik

Fibres & Textiles in Eastern Europe

2022

Vol. 30, no. 3

93--101

Polymers derived from renewable sources which are additionally subject to degradation processes are currently an interesting alternative to conventional polymers of petrochemical origin. One of such polymers is poly(lactic acid) (PLA), which can be used in the packaging, textile and also medical industries. Its great advantage is the susceptibility to biodegradation and the nontoxicity of the degradation products. Because of high brittleness and stiffness, the modification of PLA is necessary to improve its plastic deformability, which can expand the new application possibilities. As part of the research work, the modification of PLA by plasticisation was undertaken to improve its plastic deformability properties. The low molecular mass esters from the citrate group and glycerol triacetate were used. The samples extruded from plasticised polymer were characterised using Differential Scanning Calorimetry (DSC) and Gel Permeation Chromatography/Size Exclusion Chromatography (GPC/SEC). The mechanical properties and melt flow rate after modification were determined. The aim of the research was to determine the relationship between the structure of a plasticiser and its ability to reduce the interactions in the polymer chain in order to develop an optimal polymerplasticiser arrangement. Based on this research, there was no relationship between the efficiency of the plasticisation process and the increasing molecular mass of the plasticiser. The additional chemical (acetyl) group in the plasticiser also does not increase the efficiency of the PLA plasticisation process. In the next steps of the research, functional forms will be produced, i.e. fibers, films, and fittings from the selected polymer-plasticiser systems.

Badania porównawcze własności materiałów modelowych uzyskiwanych różnymi metodami

Świątkowski K.

Rudy i Metale Nieżelazne

2005

R. 50, nr 8

448-451

Przedstawiono wyniki badań krzywych umocnienia oraz granicy plastyczności próbek cylindrycznych, wykonanych z materiałów modelowych o zróżnicowanym składzie. Próbki te uzyskano na drodze klasycznego topienia oraz na drodze wyciskania. Krzywe umocnienia uzyskano w próbie spęczania. Posłużyła ona do otrzymania granicy plastyczności. Otrzymane wyniki wskazują na istotny wpływ metody otrzymywania próbek na przebieg krzywych umocnienia własności mechanicznych próbek. Opracowano procedury przygotowania próbek w postaci wlewków okrągłych, uzyskanych w procesie krzepnięcia we wlewnicy metalowej. Jako materiał modelowy zastosowano mieszaniny plasteliny z kaolinem, kredą i FILIĄ. Równocześnie zastosowano metodę wyciskania takich samych wlewków, z których następnie wykonano próbki do badań charakterystyk mechanicznych w procesie spęczania. Uzyskano zależności sigma = f(varepsilon), które mogą być wykorzystane do modelowania procesów odkształcania plastycznego metali na zimno.

The results of investigations of constitutive equations and mechanical properties of model materials were presented in the paper. Cylindrical samples were manufactured in the casting and extrusion processes. The special procedures of cylindrical samples preparation by using of casting method were elaborated and also special tool for extrusion process. The constitutive equations and the mechanical properties of samples made of mixtures of plasticine with kaolin, chalk and modelling wax FILIA were obtained in compression tests. A distinct influence of the samples method preparation on the obtained stress-strain relationships were observed. Obtained relationships sigma =f(varepsilon), can be used to the physical modelling of metal working processes.