scholarly journals Auxetic polyurethane foams – method for determining a softening point

2017 ◽  
Vol 40 (2) ◽  
pp. 5-38
Author(s):  
Janusz Lisiecki
Keyword(s):  
Polyurethane Foam ◽  
Softening Point ◽  
Annealing Temperature ◽  
Polyurethane Foams ◽  
The Way

Abstract The article described selected methods for determining a softening point of plastics (polymers). The way of determining a softening point of polyurethane foams was suggested. Moreover, the influence of annealing temperature of an auxetic polyurethane foam on its volume was presented.

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.

Raman Spectra of Ion Implanted Graphite

1981 ◽  
Vol 7 ◽  
Author(s):  
B.S. Elman ◽  
H. Mazurek ◽  
M.S. Dresselhaus ◽  
G. Dresselhaus
Keyword(s):  
Raman Spectroscopy ◽  
Ion Implantation ◽  
Raman Spectra ◽  
Annealing Temperature ◽  
Annealing Process ◽  
Lattice Order ◽  
Annealing Temperatures ◽  
High Fluences ◽  
Lattice Damage ◽  
The Way

ABSTRACTRaman spectroscopy is used in a variety of ways to monitor different aspects of the lattice damage caused by ion implantation into graphite. Particular attention is given to the use of Raman spectroscopy to monitor the restoration of lattice order by the annealing process, which depends critically on the annealing temperature and on the extent of the original lattice damage. At low fluences the highly disordered region is localized in the implanted region and relatively low annealing temperatures are required, compared with the implantation at high fluences where the highly disordered region extends all the way to the surface. At high fluences, annealing temperatures comparable to those required for the graphitization of carbons are necessary to fully restore lattice order.

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 Effective polyurethane compositions filled with industrial wastes

2018 ◽  
Vol 7 (2.13) ◽  
pp. 240
Author(s):  
Goncharova Margarita Alexandrovna ◽  
Korneeva Anastasia Olegovna ◽  
Korneev Oleg Olegovich ◽  
Hameed Ghalib Hussain Al-Surraiwy
Keyword(s):  
Polyurethane Foam ◽  
Residential Buildings ◽  
Converter Slag ◽  
Sandwich Panels ◽  
High Strength ◽  
Average Density ◽  
Polyurethane Foams ◽  
Industrial Wastes ◽  
Building Structures ◽  
Coefficient Of Thermal Conductivity

Formulations are developed and optimized for of rigid polyurethane foams filled with converter slag. The optimum content of the filler is 30%. Polyurethane compositions have the following characteristics: average density – 42.59 kg/m3, compressive strength at 10% deformation – 0.293 MPa, water absorption by volume 1.71%, coefficient of thermal conductivity – 0.028 W/m·0C. Polyurethane foams are applied in sandwich panels, multi-layer roof constructions and for the manufacture of fixing systems for metal rolled.Sandwich panels with polyurethane foam insulation and sheathing of specialized panels are designed for the construction of pre-fabricated residential buildings. The forecasting of polyurethane durability in building structures as thermal insulation in sandwich panels the foam lifespan is about 75 years, which is approximately two times greater than that of the unreinforced foam.Layered roof structures with modified rigid polyurethane foam are used for buildings and structures for various purposes. Their use makes it possible to solve several tasks: creating a complete architectural image, ensuring high strength and deformation characteristics with good noise and heat insulation, minimization when mounting. The use of lightweight, transportable and technologically advanced roofing elements in conditions of mass production creates significant opportunities for industrial construction. The proposed foam fixing systems during shipping rolled metal in containers makes it possible to exclude the possibility of the longitudinal and transverse shift of pallets with rolls, to protect metal from damage, to simplify the design of the foxing elements, reduce the production cost, and minimize the amount of time for fixing metal rolls in the container.  

Failure of Polyurethane Foams under Different Loading Conditions

2008 ◽  
Vol 385-387 ◽  
pp. 205-208 ◽  
Author(s):  
Liviu Marsavina ◽  
Tomasz Sadowski ◽  
Dan Mihai Constantinescu ◽  
Radu Negru
Keyword(s):  
Mechanical Properties ◽  
Polyurethane Foam ◽  
Polyurethane Foams ◽  
Experimental Results ◽  
Loading Conditions ◽  
Sandwich Composites ◽  
Considerable Influence ◽  
Three Point Bending

Polyurethane foam materials are widely used as cores in sandwich composites, for packing and cushioning. This paper presents the experimental results obtained for the mechanical properties of polyurethane foams in different loading conditions and the influence of impregnation on the mechanical properties. A 200 kg/m3 density polyurethane foam was tested in tension, compression and three point bending. The experimental results show that the impregnation layer has no effect on the strength of the foam, but has considerable influence on the tensile and flexure modulus.

Laboratory plant for evaluation of burnout rate of various materials

2021 ◽  
pp. 19-23
Author(s):  
Н.П. Копылов ◽  
Е.Ю. Сушкина ◽  
В.И. Новикова ◽  
В.В. Яшин
Keyword(s):  
Induction Period ◽  
Flame Retardant ◽  
Polyurethane Foam ◽  
Beech Wood ◽  
Polyurethane Foams ◽  
Air Flow Rate ◽  
Linear Section ◽  
Significant Discrepancy ◽  
Burnout Rate ◽  
Burn Rate

Описана методика исследования скорости выгорания различных материалов. Для реализации методики создана лабораторная установка. Экспериментально установлено, что процесс выгорания материалов зависит от температуры реактора и скорости воздушного потока. Кривая выгорания имеет S-образный вид и три характерных участка: индукционный период, линейный участок и участок реакции, где происходит выгорание углеродистого остатка. В табличной форме представлены результаты исследования некоторых широко распространенных материалов. The article describes a method for studying the burnout rate of various materials. There was created the laboratory plant for implementation of the method. It is experimentally established that the process of burnout of materials depends on the temperature of the reactor and the air flow rate. The burn-up curve has an S-shape and three characteristic sections: the induction period, the linear section, and the reaction section where the carbon residue burns out. The article presents the results of study of some widely distributed materials in tabular form. The mass burn rate of beech wood is 1.5 times higher than that one of pine. Perhaps this is due to the impregnation of beech with furniture varnish, since the sample was part of the furniture lining. It is noteworthy that significant discrepancy in the burn-up rates was obtained during combustion of samples of different brands of polyurethane foams. So, for hard polyurethane foam - “izolan 2”, which has a flame retardant in its composition, burnout curves with longer induction period are obtained (as a result of flame retardant action). However, the burnout rate is higher in comparison with soft polyurethane foam without flame retardant (foam rubber). The composition of the material “isolan-2”. Rubber also has a long induction period, but a high burnout rate.

Synthesis and Characterization of Bio-Based Rigid Polyurethane Foams with Varying Amount of Blowing Agent

2019 ◽  
Vol 803 ◽  
pp. 346-350
Author(s):  
Jessalyn C. Grumo ◽  
Lady Jaharah Y. Jabber ◽  
Arnold A. Lubguban ◽  
Rey Y. Capangpangan ◽  
Arnold C. Alguno
Keyword(s):  
Polyurethane Foam ◽  
Functional Group ◽  
Polyurethane Foams ◽  
Synthesis And Characterization ◽  
Rigid Polyurethane Foam ◽  
Sem Images ◽  
Average Cell Size ◽  
Average Cell ◽  
Blowing Agent

We report on the rigid polyurethane foam (RPUF) with varying amount of blowing agent. The effects of blowing agent in the formation of polyurethane will be characterized using scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. SEM images revealed that varying the amount of blowing agent will significantly change the surface morphology of the resulting RPUF. The average cell size of the RPUF increases with increasing amount of blowing agent. Moreover, FTIR results revealed the presence of functional group related to formation of urethane bonds such as N-H, C=O, C=N and C-O-C stretching suggesting that polyurethane foam was successfully synthesized. This simple and straightforward process of RPUF using water as blowing agent will be economical.

scholarly journals Osseodensification Drilling vs. Standard Protocol of Implant Site Preparation: An In Vitro Study on Polyurethane Foam Sheets

Prosthesis ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 76-86
Author(s):  
Luca Comuzzi ◽  
Margherita Tumedei ◽  
Adriano Piattelli ◽  
Giovanna Iezzi
Keyword(s):  
Polyurethane Foam ◽  
Cortical Layer ◽  
Polyurethane Foams ◽  
Insertion Torque ◽  
Standard Type ◽  
Removal Torque ◽  
In Vitro Investigation ◽  
Posterior Maxilla ◽  
And Control

(1) Background: The aim of the present in vitro investigation was to evaluate, on polyurethane sheets, two different drilling techniques for dental implant positioning using osteocondensing burs compared to a standard type protocol. (2) Methods: Three different implant designs (Implacil De Bortoli UN III 4 × 10 mm, Restore RBM 4 (HEX) × 10 mm; Implacil De Bortoli UN II 4 × 10 mm) were evaluated (test implant (osteocondensing drills) and control implant (standard drills)). The insertion torque (IT), the removal torque (RT) and the resonance frequency analysis (RFA) values of test and control implants inserted in different size and different density polyurethane foam models were compared for 120 experimental sites. Accordingly, 120 experimental holes were produced in different PCF polyurethane foams: 60 sites were produced in 10 PCF sheets and 60 sites in 10 PCF sheets with an additional 1 mm layer of 30 PCF. (3) Results: The IT, removal torque and RFA values were significantly higher for both of the evaluated implants, in the sites prepared with the osteocondenser drills when compared to sites prepared with standard drills (p < 0.05). The UNII and UN III showed significantly higher stability compared to the HEX implant; these differences increased drastically in the 10 PCF Polyurethane Block with the additional 1 mm cortical layer (p < 0.05). (4) Conclusions: The outcome of this investigation suggested a possible clinical application of osteocondensing burs in case of reduced bone quality and quantity in the posterior maxilla.

Preparation of rigid polyurethane foams with powder filler

2012 ◽  
Vol 32 (2) ◽  
Author(s):  
Joanna Paciorek-Sadowska ◽  
Bogusław Czupryński ◽  
Joanna Liszkowska ◽  
Kazimierz Piszczek
Keyword(s):  
Compressive Strength ◽  
Polyvinyl Chloride ◽  
Softening Point ◽  
Processing Parameters ◽  
Polyurethane Foams ◽  
Favorable Effect ◽  
Start Time ◽  
Rigid Polyurethane Foams ◽  
Powder Filler ◽  
Foam Plastics

Abstract The diversified properties of polyurethane (PUR) foam plastics result from differences in the receipts applied during their preparation. The preparation of rigid polyurethane-polyisocyanurate foams (PUR-PIR) with application of different amounts of polyvinyl chloride (PVC) s-70 as a filler is described in this study. It was found that application of PVC s-70 has an effect on the prolongation of processing parameters, i.e., start time and, to a greater extent, expansion and gelation times. Moreover, it was found that introduction of filler into the foam composition causes a reduction in the capacity of the foam to absorb water; however, a distinct change in the amount of closed cells in comparison with standard foam was not observed. A favorable effect of filler on brittleness and flammability of PUR-PIR foams (significant reduction) as well as on compressive strength and softening point (a significant increase in these values) was observed.

Preparation of open cell rigid polyurethane foams and modified with organo-kaolin

2019 ◽  
Vol 56 (4) ◽  
pp. 435-447
Author(s):  
Guojian Wang ◽  
Tao Yang
Keyword(s):  
Compressive Strength ◽  
Polyurethane Foam ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Polyurethane Foams ◽  
Compressive Property ◽  
Rigid Polyurethane Foam ◽  
Open Cell ◽  
Silane Coupling ◽  
Cell Opening

The open cell rigid polyurethane foam (ORPUF) was prepared by adding chemical cell openers including O-500 and AK-9903. The FTIR results of cell openers and open cell rate of ORPUFs showed that O-500 has more effective cell opening capacity. In the ORPUF foaming formulation using O-500 as cell opener, silane coupling agent (KH-550) modified kaolin (organo-kaolin) was introduced into ORPUF with different weight loadings. The cellular morphology, apparent density, and compressive strength of the foams were tested in order to investigate the effects of organo-kaolin on the open cell rate and compressive property of the foams. The results showed that the open cell rate of ORPUFs slightly increased from 83.9% to 92.9% with the content of organo-kaolin. Meanwhile, compared to neat ORPUF, the compressive strength of foams increased by 72.8% when the content of introduced organo-kaolin was 4 parts per hundred of polyol by mass (php).

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