scholarly journals DIMENSIONALLY STABLE WATER-BLOWN POLYURETHANE FOAM EXTENDED WITH BIO-BASED PROPYLENE GLYCOL AND MODIFIED WITH PAPER WASTE SLUDGE

2017 ◽  
Vol 9 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Agnė KAIRYTĖ ◽  
Aiga IVDRE ◽  
Saulius VAITKUS
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Propylene Glycol ◽  
Polyurethane Foam ◽  
Environmental Problem ◽  
Diffusion Rate ◽  
Blowing Agent ◽  
Waste Sludge ◽  
Paper Waste ◽  
High Diffusion Rate

Paper waste sludge (PWS) is the main and the greatest by-product in paper production process, and its elimination as well as destruction is a primary environmental problem. This research explores the feasibility of such wastes to be used in polyurethane foam composites. It is well known that using water as a sole blowing agent has major drawbacks such as long demould time, shrinkage, high diffusion rate of carbon dioxide and etc.; therefore, the bio-based propylene glycol (RPG) is used in order to solve such problems. The addition of 20 parts by weight (pbw) of RPG eliminates the primary shrinkage of the foam composites when PWS is used in the amount varying from 5% to 20%, and improves the dimensional stability at 70 oC and 90% relative humidity conditions. The addition of titanate coupling agent modified PWS particles increases the compressive strength of the final composites from ̴ 26% to ̴ 53%, from ̴ 17% to ̴ 31% and from ̴ 3% to ̴ 23% for, respectively, 10 pbw, 15 pbw and 20 pbw RPG extended foam composites.

Paper waste sludge enhanced eco-efficient polyurethane foam composites: Physical-mechanical properties and microstructure

2016 ◽  
Vol 39 (6) ◽  
pp. 1852-1860 ◽  
Author(s):  
Agnė Kairytė ◽  
Mikelis Kirpluks ◽  
Aiga Ivdre ◽  
Ugis Cabulis ◽  
Sigitas Vėjelis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyurethane Foam ◽  
Waste Sludge ◽  
Paper Waste

scholarly journals THE IMPACT OF CHAIN EXTENDER ON THE PROPERTIES OF POLYURETHANE FOAM BASED ON RAPESEED OIL POLYOL OBTAINED VIA CHEMO–ENZYMATIC ROUTE

2016 ◽  
Vol 8 (3) ◽  
pp. 101-107 ◽  
Author(s):  
Agnė Kairytė ◽  
Saulius Vaitkus ◽  
Giedrius Balčiūnas
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Propylene Glycol ◽  
Polyurethane Foam ◽  
Rapeseed Oil ◽  
Corn Starch ◽  
Enzymatic Route ◽  
The Impact

Presently, researches regarding green chemistry are conducted due to its significance for the mitigation of environmental problems, particularly those related to carbon dioxide emissions in relation to global warming and the usage of fossil feedstocks not only for energy generation but also for materials production. The study examines the impact of bio-products such as corn starch, rapeseed glycerin as well as petroleum based propylene glycol as bifunctional and trifunctional chain extenders on physical-mechanical properties of polyurethane foam from rapeseed oil polyol derived via chemo-enzymatic route. The obtained foams were characterized using European and international methodologies for determination of density, compressive strength perpendicular and parallel to foaming directions, thermal conductivity, long-term water absorption after 28 days of immersion, closed cell content and cell size. Foams containing (5–25) pphp of corn starch display significantly lower values in density and compressive strength as well as cell size compared to the neat polyurethane foam. The greatest compressive strength and the lowest thermal conductivity are obtained for foams with 25 pphp of rapeseed glycerin. All foams extended with bio-products and propylene glycol are characterized by the higher long-term water absorption compared to that of the neat polyurethane foam.

Effect of CO2 Curing on the Strength of High Strength Pervious Concrete

2020 ◽  
Vol 846 ◽  
pp. 207-212
Author(s):  
Ming Gin Lee ◽  
Yung Chih Wang ◽  
Wan Xuan Xiao ◽  
Ming Ju Lee ◽  
Tuz Yuan Huang
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
High Strength ◽  
Pervious Concrete ◽  
Control Group ◽  
Curing Time ◽  
Compressive Strength Of Concrete ◽  
Curing Pressure

This study was conducted to assess the effect of CO2 curing on the compressive strength of high strength pervious concrete. The factors studied to evaluate compressive strength of concrete on CO2 curing pressure, curing time, and age of specimen at testing. Three Aggregate sizes, three CO2 curing pressures, three CO2 curing time, and three testing ages were used in this investigation. The research tried to produce a high strength pervious concrete and use carbon dioxide for curing to find out whether it could enhance the compressive strength. The results show that the compressive strength of the control group increases rapidly and its 90-day compressive strength closed to 60 MPa. The 1-day compressive strength has a major impact after CO2 curing and their strength decreased by about 0% to 50% as compared to the control group. However, it is observed that there is only slight difference in relationship between modulus of elasticity and compressive strength obtained from 100 by 200mm cylinders with CO2 curing.

Development of Water Blown Bio-Based Thermoplastic Polyurethane Foams

2012 ◽  
Vol 584 ◽  
pp. 361-365 ◽  
Author(s):  
Baralu Jagannatha Rashmi ◽  
Daniela Rusu ◽  
Kalappa Prashantha ◽  
Marie France Lacrampe ◽  
Patricia Krawczak
Keyword(s):  
Compressive Strength ◽  
Cell Size ◽  
Surfactant Concentration ◽  
Thermoplastic Polyurethane ◽  
Polyurethane Foams ◽  
Chain Extender ◽  
Morphological Properties ◽  
Foam Sample ◽  
Glass Transition Temperatures ◽  
Blowing Agent

Water blown biobased thermoplastic polyurethane (TPU) foams were prepared using synthetic and biobased chain extender. The concentration of chain extender, blowing agent (BA) and surfactant were varied and their effects on physical, mechanical and morphological properties of foams were investigated. Density, compressive strength and modulus of foams decreases with an increase in BA content and increased with chain extender concentration, but do not change significantly with change in surfactant concentration. The glass-transition temperatures of the foam samples increases with an increase in BA and chain extender concentration. The cell size of the foam sample increases slightly with an increase in BA whereas chain extender concentration has no effect on cell size.

Temperature dependency of the long-term thermal conductivity of spray polyurethane foam

2021 ◽  
pp. 174425912110454
Author(s):  
Neal Holcroft
Keyword(s):  
Thermal Conductivity ◽  
Polyurethane Foam ◽  
Cellular Structure ◽  
Gas Diffusion ◽  
Temperature Dependent ◽  
Blowing Agent ◽  
Closed Cell ◽  
Wall Assembly ◽  
Cell Foam

The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.

scholarly journals Carbon-Negative Cement Manufacturing from Seawater-Derived Magnesium Feedstocks

2021 ◽  
Author(s):  
Palash Badjatya ◽  
Abdullah Akca ◽  
Daniela Fraga Alvarez ◽  
Baoqi Chang ◽  
Siwei Ma ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Portland Cement ◽  
Energy Use ◽  
Source Material ◽  
Magnesium Ions ◽  
Cement Manufacturing ◽  
Carbon Dioxide Co2 ◽  
Carbonation Curing ◽  
Free Magnesium

This study describes and demonstrates a carbon-negative process for manufacturing cement from widely abundant seawater-derived magnesium (Mg) feedstocks. In contrast to conventional Portland cement, which starts with carbon-containing limestone as the source material, the proposed process uses membrane-free electrolyzers to facilitate the conversion of carbon-free magnesium ions (Mg2+) in seawater into magnesium hydroxide (Mg(OH)2) precursors for the production of Mg-based cement. After a low-temperature carbonation curing step converts Mg(OH)2 into magnesium carbonates through reaction with carbon dioxide (CO2), the resulting Mg-based binders can exhibit compressive strength comparable to that achieved by Portland cement after curing for only two days. Although the proposed “cement-from-seawater” process requires similar energy use per ton of cement as existing processes, its potential to achieve a carbon-negative footprint makes it highly attractive to decarbonize one of the most carbon intensive industries.

scholarly journals Reliability of Unconventional Concrete: Improvement in Mix Design and Addition of Bacterial Admixture

2021 ◽  
Vol 9 (11) ◽  
pp. 136-149
Author(s):  
Burhan Afzal
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Silica Fume ◽  
Carbon Dioxide Emissions ◽  
Substantial Reduction ◽  
Bacillus Sphaericus ◽  
Industrial Wastes ◽  
Engineering Properties ◽  
Environmental Damage

Abstract: Portland cement is used by the construction industries, which is known to be a heavy contributor of carbon dioxide emissions and environmental damage. Adding of industrial wastes like demolished old concrete OF structures, silica fume (SF) fly ash (FA) as additional cementing materials (SCMs) could result in a substantial reduction of the overall Carbon dioxide trace marks of the final concrete product. Use of these additional materials in construction industry especially in the making of concrete is highly challenging. Remarkable research efforts are needed to study about the engineering properties of concrete incorporating such industrial wastes. Present research is an effort to study the properties of concrete adding industrial wastes such as demolished concrete, FA and SF The improvement of properties of RCA concrete with the incorporation of two ureolytic-type bacteria, Bacillus subtilis and Bacillus sphaericus to improve the properties of RCA concrete. The experimental investigations are carried out by experts evaluate the improvement of the compressive strength, capillary water absorption and drying shrinkage of RCA concrete adding bacteria. Seven concrete mixes are manufactured using Portland slag cement (PSC) partially changed with SF ranging from 0 to 30%. The mix proportions were obtained as per Indian standard IS: 10262-2009 with 10% extra cement when SF is taken as per the above the construction practice by experts. Optimal dosages of SF for maximum values of compressive strength, tensile splitting strength and flexural strength at 28 days are determined. Keywords: Bacillus subtilis, Bacillus sphaericus, RCA, PSC, Silica Fume.

scholarly journals Bio-based rigid polyurethane foam prepared from apricot stone shell-based polyol for thermal insulation application – Part 2: Morphological, mechanical, and thermal properties

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6080-6094
Author(s):  
Muhammed Said Fidan ◽  
Murat Ertaş
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Polyurethane Foam ◽  
Flame Retardants ◽  
Compressive Modulus ◽  
Cell Diameter ◽  
Mechanical And Thermal Properties ◽  
Rigid Polyurethane Foam

The procedure for the liquefaction of apricot stone shells was reported in Part 1. Part 2 of this work determines the morphological, mechanical, and thermal properties of the bio-based rigid polyurethane foam composites (RPUFc). In this study, the thermal conductivity, compressive strength, compressive modulus, thermogravimetric analysis, flammability tests (horizontal burning and limited oxygen index (LOI)) in the flame retardants), and scanning electron microscope (SEM) (cell diameter in the SEM) tests of the RPUFc were performed and compared with control samples. The results showed the thermal conductivity (0.0342 to 0.0362 mW/mK), compressive strength (10.5 to 14.9 kPa), compressive modulus (179.9 to 180.3 kPa), decomposition and residue in the thermogravimetric analysis (230 to 491 °C, 15.31 to 21.61%), UL-94 and LOI in the flame retardants (539.5 to 591.1 mm/min, 17.8 to 18.5%), and cell diameter in the SEM (50.6 to 347.5 μm) of RPUFc attained from liquefied biomass. The results were similar to those of foams obtained from industrial RPUFs, and demonstrated that bio-based RPUFc obtained from liquefied apricot stone shells could be used as a reinforcement filler in the preparation of RPUFs, specifically in construction and insulation materials. Moreover, liquefied apricot stone shell products have potential to be fabricated into rigid polyurethane foam composites.

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