This paper inspects the response of the warm insurance covering of rigid foam polyurethane (PU) got from castor oil (Ricinus communis) in heat conditions, taking into account dynamic environment approach. Liners have been extensively used, in light of the fact that the incorporation of structures is subject for the best maintenance of warmth by radiation, yet the usage of PU foam got from this vegetal oil is extraordinary and has the potential gain of being biodegradable and practical. The hot wire equivalent procedure gave the warm conductivity assessment of the foam. The thermo gravimetric examination engaged the examination of the foam weakening and its lifetime by powerful evaluation that incorporates the rot cycle. The PU foam warm direct examination was performed by social event test data of inside surface temperature assessed by thermocouples and assessed by delegate scene of the climatic fact. The results lead to the end that the PU foam got from castor oil can be applied to warm security of housetop systems and is an earth neighborly material.

1. Presentation

The essential target of this paper discusses the PU foam’s warm lead when applied as warm securing covering in test cells in relative assessment among four unmistakable conditions, using the air data examination subject to the possibility of specialist scene of the climatic truth. This paper similarly chooses the conductivity coefficient of PU foam and its lifetime by the rot cycle energy.

Utilizing materials that guide heat insurance had its beginning in 1940s, attempting to diminish utilizes on warming in countries with colder winters. In any case it was in the after war society numerous years, some place in the scope of 1970s and 1980s, with oil costs rising, that the regard for the prerequisite for diminishes in energy usage was more expansive. In Brazil, the market of warm insurance things that joins at any rate two structure segments emerged during the 1980s. Recently, the country has gotten a wide variety of things for heat assurance, which is used in housetop structures and side bolts, rooftops and floors (Moura, 2010).

Among the various usages of warm assurance, linings have been comprehensively used, since the consideration of structures is responsible for the best maintenance of warmth by radiation (Teemusk and Mander, 2009). There are various materials used in warm insurance, for instance, polystyrene, polyurethane, glass downy, rock and even earthenware production. The all-encompassing polystyrene and polyurethane foam (from oil) are appeared for security at lower temperatures, anyway never more than 80 °C or 90 °C, as they are powerless to defilement by heat movement. Because of high temperatures, wool based materials show better execution. Glass wool bears temperatures of around 250 °C; rock downy maintains higher temperatures and the earth wool can endure temperatures more than 1000 °C (FAO, 2010).

This work is huge and imaginative as it presents the presumable usage of rigid foam polyurethane (PU) got from castor oil (Ricinus communis) as a covering in the warm direct of housetop systems in structures as a choice as opposed to materials right currently advanced. This PU unbendable foam can be seen as such a material for “reasonable plan” (Preigaukas, 2011) because it begins from a plant helpfully created and used in agribusiness for soil nitrification, during the time spent reap upset. The advancement of castor bean has made situations in nation zones, with government maintain, since castor oil is used to convey bio energizes (green oil) (Cangemi et al., 2010). Exactly when used as security the foam presents two significant properties: in case of fire no risky gases are conveyed, and PU foam is absolutely biodegradable (Cangemi et al., 2008).

This foam was made by the Group of Analytical Chemistry and Polymer Technology (GQATP) at the Chemistry Institute of São Carlos, University of São Paulo, and is exhibited by Cequil-Central Ind. Des. Polímeros Ltda. association arranged in the city of Araraquara, São Paulo, Brazil.

1.1. Dynamic air approach: delegate scene of the climatic reality

Monteiro (1973) communicated that it is basically possible to fathom the development of air through joint examination of climatological data got by units of requested time, at any rate step by step, which identify with the depiction of commonplace scale wind current, featuring the movement of air states. Through those rhythms, conveyed by the climatic parts, it is possible to settle down scenes depicted and specialist, through plans of the atmosphere, that addresses even more fittingly the climatic reality (Vecchia, 1997).

As demonstrated by Vecchia (1997), the dynamic procedure that isolates the scenes is the force and length of each air mass which overpowers over the spot. By virtue of the region of São Paulo, Brazil, the action of Polar Atlantic masses (mPA) or Tropical Atlantic masses (mTA) may be essentially blazing, solidified, clearly, the pattern of warmth gains by sun arranged radiation.

The scenes should be depicted by their repercussion on the collected space and, explicitly, on the structure envelope, portraying their warm and energy evaluation. The general evaluation of those envelopes impacts the warm vibes of the human animal improving conditions of warm weight. Thusly, it is possible to depict a specialist scene of the climatic fact, in limit of the warm weight constrained on vibes of Human Comfort. It is of focal importance for this data variety to make sure to consider topographical parts change (Vecchia, 1998).

In the wake of researching the scene truly illustrative of environment, one day may be picked as illustrative of atmosphere capacities, for deceivability of the object of study (Givoni et al., 2001). In this manner, the correct usage of air components depends upon the audit strings sorts of atmosphere, from neighborhood responses accumulated during that time by day and hourly assortments of the segments of air (surface assessments, through stations and meteorological stations) and pictures gave by meteorological satellites (Vecchia, 1998). The air data assessment normally incorporates the yearly instances of the basic climatic components affecting human comfort and the warm exhibition of structures (Givoni, 1992). In any case, basic permission to this data base isn’t adequate. It is crucial for the correct interpretation of characteristics for the real appreciation of climatic cycles (Vecchia, 1997).

2. Trial strategies

2.1. The hot wire equivalent technique .

The hot wire equivalent technique licenses choosing the three warm properties simultaneously: warm conductivity, warm diffusivity and express warmth (Santos et al., 2004). Warm conductivity is the property that sets up the level of working temperature of a material; it is a huge limit in issues incorporating heat move in reliable state. Warm diffusivity is an assessment of the speed at which warmth multiplies through the material and is huge in issues including touchy state heat exchange. The specific warmth is a thermodynamic sum, critical at high temperatures, and related with energy use during warming (Santos, 2002).

The test includes in changing the resistance and thermocouple in equivalent with the objective that they are at the point of convergence of the model (Fig. 1) for the predictable electric stream that experiences the wire to convey a reliable proportion of warmth per time unit and length unit, which will cause through the material.


This was standardized in 1978 by DIN 51046-Part 2. According to the norm, the warm conductivity is resolved using only two motivations behind the warm transient. Right when a sentence of test warm transient is thought about, the warm conductivity is resolved every two concentrations and a while later a fundamental number shuffling mean of the decided characteristics is found. As the glow is outfitted by a slim electric hindrance with a specific warmth limit, the model is restricted, there is a contact resistance between the wire and the model, and the test has a base and a biggest opportunity to be used in the assessment of warm conductivity. In our test the figuring was performed by an item program made by Professor Wilson Nunes dos Santos, from the Engineering Materials Department, at the Federal University of São Carlos, São Paulo, Brazil.

2.2. Thermo gravimetric examination (TGA)

TGA is where the guide to be dismembered is put on scales and in an oven. The temperature is adjusted and the stuff records the mass adversity, procuring all warm crumbling (Claro Neto, 1997). In this work the instances of rigid polyurethane foam were researched with two objections: to check the weakening advances and to choose its lifetime by assessment of energy of the cycle being referred to.

The examination of disintegration steps allowed choosing the significant temperature extent of the material, for instance with no change in its engineered robustness. The examination of the thermo gravimetric twists, when performed at different warmth extents, considers a functioning appraisal by strategies for a mathematical assessment using the Ozawa–Flynn–Wall model (ASTM, 2005).

For the thermo gravimetric examination, the SDT Q 600 model from TA Instruments was used. The objective of the TGA is to look at the crumbling of the foam at different temperatures.

2.3. PU foam warm assurance

The PU foam made out of castor oil and a pre-polymer subject to MDI (diphenylmethane diisocyanate) was procured by mixing the parts in the mass degree of 0.7 polyol to 1.0 pre-polymer with mechanical tumult for 20 s; it was then filled the most ideal structure. After polymerization PU foam of 40 kg/m³ thickness was obtained. For each plate 210 g polyol and 300 g pre-polymer were used, amounting to 510 g of material on each plate. For the game plan of the plates utilized in the linings of test cells 02 and 04 a cast iron of 0.50×0.50×0.03 m3 internal estimations was used. The last weight of around 400 g and 0.03 m thickness with an area of 0.25 m². The last thickness of the plates was set reliant on the materials sold as warm defenders, which have thicknesses between 25 mm and 50 mm (ISAR, 2010).

2.4. Warm conduct investigation of the PU froth got from castor oil

2.4.1. Test cells: zone and characteristics

São Carlos is arranged in a zone known as tropical or bury equatorial jungle area. The environment is dominatingly tropical (EMBRAPA, 2008), set apart by the move of two seasons: dry season with dry and warm winters (April to September) and turbulent season with boiling and clingy summers (October to March).

The overall preliminary examination included among four cover systems, as follows:

• Test Cell 01: asbestos solid tile without earth piece and PU foam lining from castor oil.

• Test Cell 02: asbestos solid tile and PU foam lining from castor oil.

• Test Cell 03: asbestos solid tile and earth piece.

• Test Cell 04: asbestos solid tile, mud piece and PU foam lining from castor oil.

The test cells are block work improvements of ended mud over “boat” of reinforced concrete with a standardized size, differentiating just in the housetop structure. Spaces are worked with fitting scale so they can keep up the linearity of the temperature data accumulated close to the authentic situation. This linearity of the assessments would not be cultivated if scale models were used instead of test cells (Vecchia, 2003).

The test cells were expected to ensure likeness to a certified condition in data making sure about. Their significant properties are near and they were engineered on the ground so that there was no shadow of various cells relating to the away from of the sun, and they had comparable conditions of reasonableness before some other atmosphere work.

The four test cells have an internal component of 2.20 m×2.70 m (Fig. 2) and rooftop stature of 2.23 m. The housetop is slanted up to around 5% (Fig. 3). Each cell has a standard port of 2.10 m×0.60 m size outside facing east and a 1.0 m×0.70 m window defying north. Portals and windows are made of Tetra Pak® plasterboard packaging.



The housetop structures are similar, beside the nonappearance or not of the part things (Table 1). Test cell 01 has quite recently the asbestos solid housetop. Test cell 02 has an asbestos solid housetop and the PU foam masterminding got from castor oil set over a wooden structure in an organization (Fig. 4b). There is a space between the asbestos solid housetop and the PU foam lining (Fig. 3). Cell 03 has an asbestos solid housetop and earth segment. There is in like manner a space between the asbestos solid housetop and aesthetic area (Fig. 3). Test cell 04 is the most complete housetop structure since it has an asbestos solid roof, terminated piece and PU foam lining. In Cell 04, the ceramic piece was made after the housetop incline, i.e., 0.30 m away from it, forming an inflatable pad. The PU foam lining was presented on ceramic piece’s inward surface by screws.

Table 1.

Component itemsThickness (cm)
Asbestos cement roof0.4
PU foam lining3.0
Ceramic slab10.0

Fig. 4. (a) Placement of the PU plates in cell 04 and (b) PU foam lining in test cell 02

The test cells grasped for the investigation are arranged in the test plot of the Laboratory Building (LCC) of the Department of Architecture and Urban Planning, Engineering School of São Carlos, University of São Paulo, arranged in São Carlos, São Paulo, Brazil (Cardoso, 2011).

2.4.2. Stuff for data grouping in the exploratory plot

The stuff of the station is given by Campbell Scientific Inc. association, liable for the arrangement and limit of meteorological data, for instance, sun based radiation, temperature and relative sogginess, wind speed and heading, air weight and precipitation. Other equipment, for instance, a 12 V battery-fueled battery, daylight based board and the CR10X information lumberjack keeps the station working.

The data from the test cells were accumulated by assessments of surface temperatures, and by strategies for 2×24 AWG type T (copper-constantin) thermocouples, with assessments at time-frames min accepted the internal surface of the materials, which appear as the last portions of the housetop structure for each test cell. The thermocouples were related with the multiplexer and the data were taken care of on the CR10X information lumberjack. After this storing, the data were moved online by modem to the Laboratory Building (LCC) PC through unequivocal programming PC208W.

The test plot arranged at the Department of Architecture and Urban Planning, Engineering School of São Carlos, University of São Paulo, holds a modified atmosphere station and the test cells used in the assessment, with the most ideal equipment presented for the obtainment of significant data.

2.4.3. Foundation of thermocouples in the test cells

The thermocouples were set in each test cell according to the parts that make every housetop structure, as the assessment would survey the warm introduction of PU foam got from castor oil in a comparative examination of four housetop systems. The fact of the matter was to record the temperature inside the outside of the last segment of the housetop system:

• TEST CELL 01: For this circumstance the thermocouple was put on the internal surface of the tiles.

• TEST CELL 02: The thermocouple was presented on the interior surface of a covering plate.

• TEST CELL 03: The terminated piece got the thermocouple on its interior surface.

• TEST CELL 04: Thermocouple was also situated on the internal surface of a covering plate.

2.4.4. Air examination

As demonstrated by Monteiro (1973), the climate of São Carlos, São Paulo, Brazil, is obliged by focal and tropical air masses, setting the state of progress between an especially dry season with warm and dry winters (April to September) and a blustery season with boiling and clammy summers (October to March). The dry season is depicted by low precipitation, low cloudy cover, low relative moistness, and beneath temperatures when differentiated and the tempestuous season, fundamentally from Tropical Atlantic and Polar Atlantic air masses in the area. The tempestuous season has high typical temperatures with ample precipitation and high relative wetness with otherworldly Equatorial Continental air mass.

The data assembled are related to the climatic beat from January to April. We picked a specialist day with regular conditions of warmth, as most extraordinary sun controlled radiation, i.e., the sky remained clear, with low cloudy cover, taking the assessments of the NormaisClimatológicas 1960–1991 (Ministério da Agriculture ReformaAgrária, 1992) as a sort of point of view.

3. Results

3.1. Hot wire equivalent system.

In the HWPM tests assessing 0.05×0.23×0.14 m3 and thickness of 37.0 kg/m3 were used. The models were placed in the gadget to ensure the best possible contact. The resistance used was KANTHAL 6.4900 Ω/m, 0.07 m arranged at the edge of the model over the width, and a K-type thermocouple in comparing with 0.015 m hindrance (Fig. 5a). Some weight was applied to the set (Fig. 5b) to ensure more critical contact between the models and the hot wire.

Fig. 5. (a) Placement of the opposition (white bolt) and thermocouple (dark bolt). (b) Final change of the PU froth test.

Albeit 15 min would be sufficient for the test, we picked a time of 30 min to guarantee a more precise outcome. In this test we utilized an electric flow of 1.1 A, and the set stayed at room temperature. The outcomes for unbending polyurethane froth tests got from castor oil were:


•SPECIFIC HEAT: 4607.15 J/kg K

•THERMAL DIFFUSIVITY: 2.65×10−7 m²/s



As indicated by boundaries followed by Professor Wilson Nunes dos Santos, the unbending froth polyurethane got from castor oil can likewise be delegated a protecting material (0.01–0.05 W/m K).

3.2. Thermo gravimetric investigation (TGA)

Fig. 6 shows the thermo gravimetric bend of PU froth got from castor oil at a warming pace of 10 °C/min and wind stream of 100 mL/min.

Fig. 6

As can be found in Fig. 6, the overall pattern of rot occurs in two stages, starting at 170 °C. According to Claro Neto (1997), the essential stage is connected with a breaking in the urethanes chains, and a short time later in the ester bonds. The PU foam got from castor oil doesn’t bear such a weakening at temperatures under 170 °C.

A mathematical treatment performed by the TA Instruments association programming (Fly-Wall-Ozawa Model) gave the results showed up in Table 2. We can derive that it takes the polymer around 14 years to achieve this change rate at reliable temperature of 81 °C.

Table 2. Estimated lifetime vs. temperature.
Temperatura (°C)Temperature (K)Lifetime (h)

The results show that at the temperature at which the material will be revealed as warm covering securing there happens no rot, guaranteeing that this liner can be used being developed.

3.3. The warm direct of the PU foam defender

São Carlos’ region has a dry season with warm and dry winter, and turbulent season with boiling and moist summer. On account of troubles with the data variety plan of test cells, the hour of study was delimited from January to April.

Inside this period a climatic scene was picked which has atmosphere with heat conditions, with low cloudy cover, no precipitation, since the foam warm lead was made defying the glow. In like manner, it was picked the specialist scene of the climate reality among March 6th, 2010 to March twelfth, 2010, i.e, among 65 to 71 days of the Julian year (the articulation “day or Julian year” isn’t commonly used, just in conditions that need to become familiar with the particular day on which the data were assembled, while the Gregorian timetable which uses a versatile course of action of hop year and can be adjusted to approach the stations shifting, finally reason chaos and weakness in environment data).

Fig. 7, Fig. 8 show data accumulated by the customized station, related to specialist scene for examined climate reality.

Fig. 7.


The impact of similar scene in inward surface temperatures of the test cells was recorded by the thermocouples introduced in every region, and it is appeared in Fig. 9.


FIG 09

Looking at the atmosphere charts for the picked scene, considering the direct of air factors during this period, it will in general be seen that there was part of an infection front which starts to tropicalize from March 07th, allowing the examination of resolute polyurethane foam warm lead as a result of hot conditions. This is certifiable in light of the fact that from March 07th, the outside air temperature (Fig. 8) forms near with the previous day, and it remains high, on account of the effect of sun situated radiation, since there is minimal cloudy cover and precipitation doesn’t occur. As the assessment object isn’t the completed air examination, the infection front area through the São Carlos’ district was not dismembered.

In the overall assessment among the four test cells, March ninth, 2010 was picked as a specialist day of rankling conditions that occur in summer–pre-winter progress, Fig. 10 and Table 3. During the current day the best impetus for overall radiation was 994 W/m2 (13:30 p.m) and the most extraordinary motivator for outside air temperature was 30.86 °C (3:00 p.m).


Table 3. Internal surface temperatures—March 9th, 2010
Test cellTemperature maximum (°C)Temperature minimum (°C)
Test cell 01 (Tile)35,61 (2 p.m)16,58 (7 a.m)
Test cell 0228,78 (4:30 p.m)17,56 (6:30 a.m)
(PU lining)  
Test cell 03 (Slab)26,02 (6:30 p.m)20,87 (7:30 a.m)
Test cell 04 (Slab)29,72 (6:30 p.m)19,23 (7:30 a.m)
Test cell 0428,94 (6 p.m)18,61(7:30 a.m)
(PU lining)  

In test cell 01 the radiation in the tiles is immediately shipped off inside as warmth on account of the low warm torpidity of the tiles and the way that they don’t have warm assurance properties. The housetop course of action of test cell 02 goes probably as a space between the housetop and the level rooftop skewed PU foam, relating to the floor. In this situation the space helps the covering insurance. Fig. 10 and Table 3 show that there is a qualification of 6.83 °C between the most extraordinary temperature came to in cell 01 (35.61 °C at 2:00 p.m) and that came to in cell 02 (28.78 °C at 4:30 p.m). In any case, due to the thickness of the plates, the warm inaction is low. Test cell 03 is the housetop system comprehensively used in structures. There is a second story room also. For this circumstance the terminated area is positively not a nice defender, anyway it is thicker than the foam lining, demonstrating more vital warm latency. By virtue of the PU lining in test cell 04 was typical a lower a motivation for its inside surface temperature, since this cell is more completed than various cells used in the examination. Regardless, for this circumstance there is no a space, simply a space of 0.30 m between the asbestos solid housetop and imaginative piece, subsequently within surface temperature of PU lining in cell 04 was higher than the internal surface temperature of terminated lump in test cell 03.

Taking a gander at the PU foam lining most noteworthy temperature of test cells 02 and 04, it might be said that what is important isn’t in the value each one came to, yet in the time they take to show up all things considered outrageous temperature.

Separating the results it was found that the quality of ensuring polyurethane foam lining decreases the glow commitment during both day and night. Another factor that helped the warm security was the presence of the second story room. The bound air inside the extra space requires longer warming ability to convey heat. The inflatable pad in cell 04 in like manner helps the security. The warm mass can help heat security when gotten together with other ensuring contraptions.

4. Ends

According to the hot wire equivalent technique, the PU foam got from castor oil can be seen as an exceptionally ensuring material. The thermo gravimetric assessment showed that the rot of the foam begins at approximately 170 °C, i.e., the PU foam has higher insurance from degradation by heat, yet it needs various tests to assert that can be recommended for assurance at temperatures more than 80 °C. Thusly, the evaluated lifetime of castor foam at consistent temperature of 81 °C is about 14 years. Various tests, nevertheless, must be performed to enhance the depiction of the material.

Concerning the close to examination of the warm lead of the foam applied by strategies for plates, it was possible to reason that the foam can lessen the glow exchange among outside and indoor conditions, reducing around 6 °C of the most outrageous inside surface temperature. This component got together with other collaborator contraptions in warm insurance can ensure more unmistakable capability to the glow exchange decline.


The makers are grateful to CNPq, FAPESP. We gratefully perceived Dr. Wilson Nunes dos Santos (Materials Engineering Department/Federal University of São Carlos); and the Laboratory Building staff for their specific assistance with the preliminaries.


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