Wyniki wyszukiwania - BazTech

1

Biobased poly(3-hydroxybutyrate acid) composites with addition of aliphatic polyurethane based on polypropylene glycols

Zarzyka Iwona, Czerniecka-Kubicka Anna, Hęclik Karol, Dobrowolski Lucjan, Krzykowska Beata, Białkowska Anita, Bakar Mohamed

Acta of Bioengineering and Biomechanics

|

2022

|

Vol. 24, no. 1

75--89

EN

Poly(3-hydroxybutyrate) (P3HB) is the most important of the polyhydroxyalkanoates. It is biosynthesized, biodegradable, biocompatible, and shows no cytotoxicity and mutagenicity. P3HB is a natural metabolite in the human body and, therefore, it could replace the synthetic, hard-to-degrade polymers used in the production of implants. However, P3HB is a brittle material with limited thermal stability. Therefore, in order to improve its mechanical properties and processing parameters by separating its melting point and degradation temperature, P3HB-based composites can be produced using, for example, linear aliphatic polyurethanes as modifiers. The aim of the study is a modification of P3HB properties with the use of linear aliphatic polyurethanes synthesized in reaction of hexamethylene diisocyanate (HDI) and polypropylene glycols (PPG) by producing their composites. Prepared biocomposites were tested by the scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TGA). Furthermore, selected mechanical properties were evaluated. It has been confirmed that new biocomposites showed an increase in impact strength, relative strain at break, decrease of hardness and higher degradation temperature compared to the unfilled P3HB. The biocomposites also showed a decrease in the glass transition temperature and the degree of crystallinity. Biocomposites obtained with 10 wt.% polyurethane synthesized with polypropylene glycol having 1000 g · mole–1 and HDI have the best thermal and mechanical properties.

2

Thermally stable biopolymer composites based on poly(3-hydroxybutyrate) modified with linear aliphatic polyurethanes– preparation and properties

Zarzyka Iwona, Czerniecka-Kubicka Anna, Hęclik Karol, Dobrowolski Lucjan, Pyda Marek, Leś Karolina, Walczak Małgorzata, Białkowska Anita, Bakar Mohamed

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 2

91--105

EN

Purpose: Poly(3-hydroxybutyrate) (P3HB) is a biopolymer, but storing products from P3HB causes the deterioration of their properties leading to their brittleness. P3HB has also low thermal stability. Its melting point almost equals its degradation temperature. To obtain biodegradable and biocompatible materials characterized by higher thermal stability and better strength parameters than the unfilled P3HB, composites with the addition of polyurethanes were produced. Methods: The morphology, thermal, and mechanical property parameters of the biocomposites were examined using scanning electron microscopy, thermogravimetric analysis, standard differential scanning calorimetry, and typical strength machines. Results: Aliphatic polyurethanes, obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycols, were used as modifiers. To check the influence of the glycol molar mass on the properties of the biocomposites, glycols with a molecular weight of 400 and 1000 g/mol were used. New biocomposites based on P3HB were produced with 5, 10, 15, and 20 wt. % content of polyurethane by direct mixing using a twin-screw extruder. The following property parameters of the prepared biocomposites were tested: degradation temperature, glass transition temperature, tensile strength, impact strength, and Brinell hardness. Conclusions: Improvement of the processing property parameters of P3HB-biocomposites with the addition of aliphatic polyurethanes was achieved by increasing the degradation temperature in relation to the degradation temperature of the unfilled P3HB by over 30 C. The performance property parameters have also been improved by reducing the brittleness compared to the P3HB, as evidenced by the increase in impact strength and the decrease in hardness with an increase in the amount of polyurethane obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycol with a molecular weight of 400 g/mol (PU400) as modifier.

3

Physical blowing agents for polyurethanes

Wianowski Leszek, Białkowska Anita, Dobrowolski Lucjan, Zarzyka Iwona

Polimery

|

2020

|

T. 65, nr 2

83--94

EN

Polyurethane foam materials are the majority among all foam materials. Additionally, they are main part of all produced polyurethanes. Therefore, the problem of selection of suitable blowing agents is very crucial from the point of view of technological, economic and environmental protection benefits. The work is collected and discussed all kinds of physical blowing agents which are used in the production of polyurethane foams. The basic blowing agents used in the polyurethane technology include: chlorofluorocarbons.

PL

Większość materiałów piankowych to piankowe materiały poliuretanowe, stanowiące główną grupę wszystkich produkowanych poliuretanów. Z punktu widzenia korzyści technologicznych, ekonomicznych i ochrony środowiska bardzo istotnym problemem jest dobór odpowiednich środków porotwórczych. W pracy omówiono rozmaite fizyczne środki spieniające wykorzystywane doprodukcji pianek poliuretanowych. Do podstawowych środków porotwórczych stosowanych w technologii poliuretanów zalicza się: chlorofluorowęglowodory (CFC), uwodornione fluorowęglowodory (HFC), uwodornione chlorofluorowęglowodory (HCFC), niskowrzące nasycone i nienasycone węglowodory, nasycone fluoroetery (HFE) i ditlenek węgla. Omówiono zagadnienia związane z problemem doboru odpowiedniego środka spieniającego, uwzględniającego jego oddziaływanie na środowisko, koszty produkcji pianki i wpływ na jej właściwości, w szczególności na termoizolacyjność i palność.