DEVELOPMENT AND RESEARCH OF POLYURETHANE FOAM COMPOSITE MATERIALS WITH LYSOZYME

2021 ◽  
Vol 43 (3) ◽  
pp. 204-213
Author(s):  
T.V. VISLOHUZOVA ◽  
◽  
R.A. ROZHNOVA ◽  
N.A. GALATENKO ◽  
◽  
...  
Keyword(s):  
Glass Transition ◽  
Composite Materials ◽  
Polyurethane Foam ◽  
Single Phase ◽  
Mechanical Tests ◽  
Polyurethane Foams ◽  
Scanning Calorimetry ◽  
Heating Capacity ◽  
Foam Composite ◽  
Treatment Of Wounds

The article is devoted to the development and research of the structure and properties of polyurethane foam (PUF) composite materials with the antibacterial enzyme lysozyme. A series of PUF composite materials with lysozyme of various concentrations (1, 3 and 5 wt %) were obtained. It is established that the immobilization of lysozyme occurs due to intermolecular hydrogen bonds by the method of IR spectroscopy. According to the results of physical-mechanical tests the adhesive strength of polyurethane foam compositions with lysozyme is in the range of 0,82–1,16 MPa. The introduction of lysozyme into the composition of polyurethane foams and an increase its amount causes a decrease in the values of adhesion strength by 18,1–29,3 %. According to differential scanning calorimetry the tested systems are single-phase with a glass transition temperature in the range of -49,20 to -49,86 °C. The introduction of lysozyme into the composition causes an increase heating capacity at the glass transition, which can be associated with a decrease of the packing density of macrochains resulting in an increase in free volume, which leads to an increase molecular mobility. According to the results of the analysis of transmission optical microscopy micrographs the studied PUF have a microporous structure, which depends on the content of filler in their composition. It was found that the presence of lysozyme in the composition of composite materials leads to a decrease in the percentage of porosity, an increase in the number of pores with a diameter of up to 300 μm, which is 76,7–82,4 % (while for PUF – 69,5 %) and the absence of pores with a diameter larger than 990 μm. Thermogravimetric characteristics indicate the heat resistance of the synthesized PUF to a temperature of 179,95 °C, which allows dry sterilization of samples without changing their characteristics. PUF composite materials with lysozyme are promising materials that can be used in medical practice as polymer compositions for the treatment of wounds and burns.

scholarly journals Natural Oil-Based Rigid Polyurethane Foam Thermal Insulation Applicable at Cryogenic Temperatures

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4276
Author(s):  
Katarzyna Uram ◽  
Aleksander Prociak ◽  
Laima Vevere ◽  
Ralfs Pomilovskis ◽  
Ugis Cabulis ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Apparent Density ◽  
Mechanical Tests ◽  
Polyurethane Foams ◽  
Cryogenic Temperatures ◽  
Rigid Polyurethane Foam ◽  
Foam Material ◽  
Rigid Polyurethane Foams ◽  
Natural Oil ◽  
Cryogenic Insulation

This paper presents research into the preparation of rigid polyurethane foams with bio-polyols from rapeseed and tall oil. Rigid polyurethane foams were designed with a cryogenic insulation application for aerospace in mind. The polyurethane systems containing non-renewable diethylene glycol (DEG) were modified by replacing it with rapeseed oil-based low functional polyol (LF), obtained by a two-step reaction of epoxidation and oxirane ring opening with 1-hexanol. It was observed that as the proportion of the LF polyol in the polyurethane system increased, so too did the apparent density of the foam material. An increase in the value of the thermal conductivity coefficient was associated with an increase in the value of apparent density. Mechanical tests showed that the rigid polyurethane foam had higher compressive strength at cryogenic temperatures compared with the values obtained at room temperature. The adhesion test indicated that the foams subjected to cryo-shock obtained similar values of adhesion strength to the materials that were not subjected to this test. The results obtained were higher than 0.1 MPa, which is a favourable value for foam materials in low-temperature applications.

scholarly journals Plasticizing Properties Improvement of Poly (4-Vinylpyridine)/Clay Composites: Effect of Composition and Clay Nature

2021 ◽  
Vol 21 (3) ◽  
pp. 5-16
Author(s):  
Fayçal Dergal ◽  
Djahida Lerari ◽  
Khaldoun Bachari
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Composite Materials ◽  
Glass Transition Temperature ◽  
In Situ Polymerization ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Composites Materials

Abstract A significant number of investigations have been reported on the elaboration and characterization of Polymer/Clays composites, via different methods. In our work, new composites materials were successfully prepared by in-situ polymerization of 4-vinylpyridine (4VP), in presence of two different types of Algerian modified clays (Maghnia and Mostaganem), noted (BC) and (MC), respectively. Different percentage clays (1 wt%, 3 wt% and 5 wt%) have been used. The differential scanning calorimetry analysis reveals the variation of glass transition temperature (Tg) of the copolymer in the composite materials. We show a decrease glass transition temperature (Tg) from 147°C to 131°C for P4VP-BC and from 147°C to 124°C for P4VP-MC according to the increase percentage of clays. Thermogravimetric analysis (TGA) shows good stability of composite materials at high temperature. Fourier Transformed Infrared (FTIR), Scanning Electron Microscopy coupled with Energy dispersive X-Ray Spectroscopy (SEM-EDX) and 1H NMR spectroscopy are used to show the presence of the clays in the materials.

A greener and sustainable approach for converting polyurethane foam rejects into superior polyurethane coatings

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mechanical Properties ◽  
Polyurethane Foam ◽  
Sebacic Acid ◽  
Polyurethane Foams ◽  
Hexamethylene Diisocyanate ◽  
Alkali Resistance ◽  
Microwave Reaction ◽  
P Recycling ◽  
Amine Groups ◽  
Green Polymer

Recycling is a crucial area of research in green polymer chemistry. Various developments in recycling are driven by Environmental concerns, interest in sustainability and desire to decrease the dependence on non-renewable petroleum based materials. Polyurethane foams [PUF] are widely used due to their light weight and superior heat insulation as well as good mechanical properties. As per survey carried Polyurethane Foam Association, 12 metric tonnes of polyurethane foam are discharged during manufacturing and/or processing and hence recycling of PUF is necessary for better economics and ecological reasons. In present study, rejects of PUF is subjected to reaction with a diethylene amine in presence of sodium hydroxide [NaOH] as catalyst, as a result depolymerised product containing hydroxyl and amine groups is obtained. Conventional and Microwave reaction for depolymerizing polyurethane foam have been carried, and best results are obtained by Microwave reaction. Further depolymerised product with hydroxyl and amine functionalities are reacted with bis (2-hydroxyethyl terephthalate) [BHET] obtained by recycling polyethylene terephthalate [PET] and sebacic acid, with stannous oxalate [FASCAT 2100 series] as catalyst to obtain Polyester amides. These Polyester amides having hydroxyl and amino groups in excess are cured with isocyanates-hexamethylene diisocyanate biuret [HDI biuret] and isophorone diisocyanate [IPDI] for coating applications. The coated films are characterized using physical, mechanical and chemical tests, which shows comparable physical, mechanical properties but alkali resistance is poor.

The Mechanical Properties of Organic Modified Epoxy Resin

2020 ◽  
Vol 43 (3) ◽  
pp. 10-14
Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Mechanical Tests ◽  
Organic Modification ◽  
Three Point Bending ◽  
Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

scholarly journals PEG-POSS Star Molecules Blended in Polyurethane with Flexible Hard Segments: Morphology and Dynamics

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 99
Author(s):  
Konstantinos N. Raftopoulos ◽  
Edyta Hebda ◽  
Anna Grzybowska ◽  
Panagiotis A. Klonos ◽  
Apostolos Kyritsis ◽  
...  
Keyword(s):  
Glass Transition ◽  
Star Polymer ◽  
Polymerization Process ◽  
Degree Of Crystallinity ◽  
Dielectric Relaxation Spectroscopy ◽  
Scanning Calorimetry ◽  
Similar System ◽  
Soft Phase ◽  
Hard Segments ◽  
Star Molecules

A star polymer with a polyhedral oligomeric silsesquioxanne (POSS) core and poly(ethylene glycol) (PEG) vertex groups is incorporated in a polyurethane with flexible hard segments in-situ during the polymerization process. The blends are studied in terms of morphology, molecular dynamics, and charge mobility. The methods utilized for this purpose are scanning electron and atomic force microscopies (SEM, AFM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and to a larger extent dielectric relaxation spectroscopy (DRS). It is found that POSS reduces the degree of crystallinity of the hard segments. Contrary to what was observed in a similar system with POSS pendent along the main chain, soft phase calorimetric glass transition temperature drops as a result of plasticization, and homogenization of the soft phase by the star molecules. The dynamic glass transition though, remains practically unaffected, and a hypothesis is formed to resolve the discrepancy, based on the assumption of different thermal and dielectric responses of slow and fast modes of the system. A relaxation α′, slower than the bulky segmental α and common in polyurethanes, appears here too. A detailed analysis of dielectric spectra provides some evidence that this relaxation has cooperative character. An additional relaxation g, which is not commonly observed, accompanies the Maxwell Wagner Sillars interfacial polarization process, and has dynamics similar to it. POSS is found to introduce conductivity and possibly alter its mechanism. The study points out that different architectures of incorporation of POSS in polyurethane affect its physical properties by different mechanisms.

Evaluation of glass transition in model cell lines using differential scanning calorimetry

Cytotherapy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. S173
Author(s):  
C. Jones ◽  
J. Heimfeld ◽  
B.J. Hawkins ◽  
R. Marcu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Cell Lines ◽  
Scanning Calorimetry ◽  
Model Cell
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