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Abstract

Due to the significant and harmful effect of the global warming on our communities, health, and climate, the usage of thermal insulation material in building is must to decrease the energy consumption and to improve energy efficiency. On the other hand, the utilization of waste and biomass resources for developing new bio-based composite materials is attracting much attention for the environmental and socioeconomics. Therefore, in this study, thermal insulation bio-based composite panels from Tetra Pak® waste and wool fiber waste with different ratios were manufactured. Likewise, other sandwich bio-based composite panels were manufactured using Tetra Pak waste as a core material with glass woven fabric and jute wove fabric as skin materials. Thermal conductivity and thermal resistance results showed a significant improvement on thermal insulation properties of the developed biocomposite panels compared to the control samples made of plain Tetra Pak®.

Keywords

Food package waste wool waste fibers glass fiber jute thermal conductivity

Introduction

With the increasing consumption of fiber reinforced polymer, environmental concerns relating to many issues such as energy-intensity, sustainability, recyclability, and biodegradability have been highlighted [1,2]. Thus, intensified efforts are being made to reduce the dependence on petroleum-based materials. Utilization of lignocellulosic materials is a rapidly growing sector, not only for the production of commodities, such as textiles, paper, and home furniture but also for specialty goods involved in automotive industries, ships, wind turbine blades, and construction panels [3 –5]. Several researches are being conducted on enhancing thermal conductivity of textile reinforced composite for insulation applications [6 –8].

Tetra Pak® is a largest producer of beverage cartons worldwide. The number of Tetra Pak packages sold in 2014 was around 180 billion packages which is around 2.5 million tons [9]. According to the company news release, just 26% of this quantity had been recycled [10]. From the previous numbers and facts, it can be concluded that huge amount of used Tetra Pak packages are not recycled which are more than 70% of the total annual production. Consequently, accumulation of this material can reach a problematic level, which will be more hazardous to the environment.

Tetra Pak packaging is made of three main components: 75% cellulose fibers, 20% low-density polyethylene (LDPE), and 5% Aluminum. The paper material used in Tetra Pak packaging is unbleached sulfate (kraft) and CTMP (chemi-thermo-mechanical process) pulp [11]. According to Tetra Pak company, recycling is divided into three categories, depending on the materials to be recycled. The first recycling method is fiber recycling (re-pulping): in this process, paper or cellulose fibers are separated from LDPE and Aluminum to reproduce paper pulp for new paper products such as corrugated cartons and consumer products, such as cardboard, paper towels, notebooks, and other new paper products [12]. The second recycle method is PolyAl: in this category, LDPE and aluminum in Tetra Pak packages are used, either together or separately, and then these are used as raw material for new products. The third recycle material is full carton; this category uses the whole package without any process of separation, whereas cellulose fibers, LDPE, and aluminum, are used to produce material for new products.

Thermal conductivity

Thermal conductivity is the flow of thermal energy through a unit thickness of a material under a temperature gradient and expressed by the coefficient of thermal conductivity [13]. Thermal conductivity is a very important parameter in determining heat transfer rate and is required for the development of drying models and in industrial operations such as adhesive curing rate [14]. Also, Thermal conductivity must be known when choosing the insulation materials to attenuate fluctuation in the out door environment which maintain an indoor temperature that is independent of outdoor temperature fluctuations. The materials used for insulation must have good warmth-keeping properties such as lower thermal diffusivity to provide sufficient protection from severe temperature changes [15]. Kawasaki and Kawai [15] also stated that plywood sandwich panels had the characteristics of well-balanced thermal insulation and warmth-keeping properties (steady- and non-steady-states), which were important for insulation performance in that they maintained temperature and relax severe temperature changes in residences exposed to diurnal and seasonal temperature changes. Wood materials possess a superior thermal conductivity properties compared to other building materials which is due to its porous structure of them [16,17]. They are one of the preferred materials in many application such as construction industry, refrigerators, automobile industry, and in the manufacture of barrels, because of their low thermal conductivity and high resistance [16]. Thermal conductivity of wood materials has varied according to wood type, direction of wood fiber, resin type, and additive members used in the manufacture of wood composite panels [18]. Natural fibers such as wool fibers are well known for their superior thermal insulation properties; therefore, they are used for building thermal insulation despite their high cost compared to other materials [19]. The main objective of this study is to decrease the thermal conductivity and enhance thermal resistance of composite material made of Tetra Pak waste for thermal insulation applications. Thus, the Tetra Pak waste can be recycled to decrease the environmental impact of such unexploited waste. On the other hand, new insulation composite materials could be created for the manufacture of great value-added applications.

Materials and methods

Shredded Tetra Pak waste packaging cartons were supplied from EKOPAN Company, Izmir, Turkey. As stated earlier, Tetra Pak waste contains 20% of LDPE; therefore, no thermoplastic or thermoset resin is required to prepare the final composite samples. This process can be considered as a recycling process to reuse the Tetra Pak waste to create a composite material suitable for insulation applications. In this study, two groups of composite samples were prepared. The first composite group contains Tetra Pak mixed with wool fiber waste at different ratios. The second composite group contains glass fiber woven fabric and jute woven fabric as a skin layer for Tetra Pak layer which is used as a core material.

Manufacturing composites from Tetra Pak waste

Composite samples were fabricated using a mold (400 mm in square shape) that was hot pressed in two stages: The first stage at 190℃–200℃ for 2 min under 29–72.5 psi (2–5 bars); the second stage at 190–200℃ for 3 min under 145 psi (10 bars) to reach the target thickness of 5 mm. The finished composites were conditioned in a climate-controlled chamber with a relative humidity of 65% ± 5% and temperature of 20℃ ± 2℃ until they reached equilibrium moisture content before testing and characterization procedures.

Tetra Pak/wool waste fiber

Wool fibers are known for their superior insulation properties as the still air is trapped within the fibers. Wool’s spinning waste is usually shredded and is used as a stuffing material. For this study, wool waste fibers acquired from YUNSA (Wool Industry and Trading, Istanbul, Turkey) are used. In this composite group, shredded Tetra Pak waste is mixed with different mixing ratios of wool waste fibers: 0%, 5%, 10%, 15%, and 20% (Figure 1). The effect of the added ratio of wool waste fibers on thermal conductivity, thermal resistance, and % difference of heat flow will be investigated. Table 1 depicts the hybrid biocomposite samples’ specifications from Tetra Pak waste and wool waste fibers. TP and W represent Tetra Pak® and wool waste fibers, respectively.

Figure 1.

Tetra Pak® mixed with wool yarn waste.

Table 1.

Description of Tetra Pak®/wool composites.

Sample ID	Wool waste content, %	Tetra Pak® waste content, %
1 TP0W	0	100
2 TP5W	5	95
3 TP10W	10	90
4 TP15W	15	85
5 TP20W	20	80

Tetra Pak (core)/woven fabric (skin)

In this section, two different woven fabric materials are used as a skin layer, glass fiber woven fabric, and jute woven fabric. Glass fiber woven roving fabric were used as skin layers. Used glass fiber fabric has an areal density of 800 g/m². The number of warp and weft yarns are equal to acquire a balance structure, while the jute fabric has a balanced plain weave 1/1 structure with an areal density of 280 g/m². Polypropylene spunbonded nonwoven fabric (12 g/m²) was used as an additional thermoplastic layer in order to enhance the adherence between the woven materials layers and Tetra Pak waste. Nonwoven polypropylene was used in some samples as a top and bottom layers, and in some samples it was placed between the woven materials and Tetra Pak as indicated in Figure 3.

Table 2 depicts the hybrid biocomposite samples’ specifications from Tetra Pak waste as core layer and woven fabric as skin layers. TP, and J, G, and PP represent Tetra Pak, jute woven fabric, glass woven fabric, and polypropylene nonwoven spunbonded fabric, respectively.

Table 2.

Description of Tetra Pak® sandwich composites.

Sample ID	Skin material
1 TP	No
2 PP-TP-PP	Polypropylene
3 J-TP-J	Jute woven fabric
4 J-PP-TP-PP-J	Jute + polypropylene
5 PP-J-TP-J-PP	Polypropylene + jute
6 G-TP-G	Glass woven fabric
7 G-PP-TP-PP-G	Glass + polypropylene
8 PP-G-TP-G-PP	polypropylene + Glass

Figure 2 illustrates the schematic diagram of sandwich hybrid biocomposite layers made of Tetra Pak, glass fiber woven fabric, and PP nonwoven. Composite structures of different manufactured samples are illustrated in Figure 3 along with sample id.

Figure 2.

Fabrication of hybrid biocomposite samples of Tetra Pak waste (core), glass fiber woven fabric, and PP (skin).

Figure 3.

Hybrid biocomposite samples orientation and identification.

Thermal insulation test

Material thermal conductivity and thermal resistance are considered an important parameter for selecting thermal insulation materials. Thermal conductivity values are related to the thickness and density of the board, the highest density boards possess the least insulating effect. This is because the low-density board contains voids with air, which is one of the poorest conductors [20]. Thermal conductivity was determined according to ASTM C518 & ISO 8301. FOX 314 Heat Flow Meter apparatus (HFM) was used to measure the steady-state heat transfer through flat materials as shown in Figure 4. A 305-mm square sample was placed between two flat plates (305 mm square) which are controlled at a specified constant temperature. Square 101 ± 1 mm HFMs are embedded in the center of the upper and lower plates to measure the heat flow through the specimen. Thermocouples are also embedded in the plates to measure the temperature drop across the specimen. Specimen’s thickness is measured in-situ with four optical encoders, one at each corner of the plate, providing stable measurements within 0.025 mm.

Figure 4.

FOX 314 heat flow meter.

The measured temperature and the HFMs for the upper and lower plates are recorded every 0.5 s. These recorded measurements are organized into groups of 512, called data blocks (one data block consisting of about 4 min of data). Each plate’s average temperature and HFM voltage is calculated for every data block and the software uses these average values to calculate the thermal conductivity using equation (1). The last three data blocks are measured when the steady state condition is reached. The device determines the steady state condition when the average temperatures of the top and bottom plates are within ± 0.2℃ and that the average HFM voltage readings for one data block are within 2% of the previous data block.

k = \frac{q ″ L}{Δ T}

(1) where k is the thermal conductivity of the specimen in W/(m · K), q″ is the heat flux in W/m², and ΔT is the temperature difference across the specimen in K. The difference in percentage between the heat flow through the top and bottom plates was calculated based on equation (2). To reduce the uncertainty in the calculated thermal conductivity,

\bar{q ″}

is used in the calculation of thermal conductivity.

% Difference = \frac{| q ″ U - q ″ L |}{\bar{q ″}}

(2) where q″ _U and q″ _L are the absolute heat flux values measured by the upper and lower HFM in W/m², respectively, and q″ is the average of q″ _U and q″ _L _.

R is the absolute thermal resistance in K/W and defined as the capacity of a material to block heat flow over a given area and under a specific temperature. The higher the value at a given set of conditions, the better the material will perform as a thermal insulator. Thermal resistance is calculated based on equation (3).

R = \frac{L}{kA}

(3) where L is the total thickness of the composite wall in m, k is the conductivity value provided by the HFM apparatus in W/(m · K), and A is the measuring area in m².

R-value is the thermal insulation and measured in m²K/W and it is the thermal resistance of a unit area of a material and is calculated based on equation (4).

R - value = \frac{L}{k}

(4)

Results and discussion

Tetra Pak/wool waste hybrid biocomposite

The thermal conductivity results of Tetra Pak/wool are shown in Table 3 and Figure 5. The results show an improvement on reducing thermal conductivity of Tetra Pak composite with incorporated wool waste fibers. The thermal conductivity of Tetra Pak composite reduced from 0.06296 W/mK to 0.06115 when mixed with 15% wt. wool waste fibers, which is approximately 3% reduction in thermal conductivity %.

Figure 5.

Thermal conductivity of Tetra Pak® waste/wool waste hybrid biocomposite.

Table 3.

Thermal conductivity values of Tetra Pak/wool composites.

Samples		Thickness (mm)	Thermal conductivity (W/mK)	Reduction in thermal conductivity (%)	Percent difference^a (%)
1	TP0W	4,94	0.06296 ± 0.001	–	0.39
2	TP5W	4,77	0.06211 ± 0.00002	1.350	0.38
3	TP10W	4,82	0.06158 ± 0.0001	2.192	0.32
4	TP15W	5,06	0.06115 ± 0.0006	2.875	0.30
5	TP20W	5,20	0.06222 ± 0.0004	1.175	0.41

Difference between the heat flow through the top and bottom plates was calculated based on equation 2.

On the other hand, sample 4 prepared with 20% wool waste fibers showed a slight reduction in thermal conductivity; this may have occurred because of the mixing process that was carried out manually which may produce a non-homogeneous mixture of Tetra Pak and wool fibers. Other results indicate that as the wool waste ratio increase, the reduction in thermal conductivity increases. Percent difference between the heat flux measured by the upper and lower HFM (% difference) revealed that as the wool fiber’s ratio increases the percent difference decreases. This indicates that the average between the two plates’ temperature is increases as the wool fiber’s ratio increases. Standard deviation indicates that the decrease in thermal conductivity is significant when wool fibers are introduced into the Tetra Pak composite. Wool fibers trapped small air in a foam-like structure; this air-trapping property is the basic principle in eliminating or reducing heat transfer from one side to another.

These thermal conductivity results are low compared with hemp-based composite materials [21]. Hemp composite with densities ranging between 0.62 and 1.28 g/cm³ showed thermal conductivity between 0.087 and 0.138 W/mK. These values are higher than the thermal conductivity of all hybrid composite samples fabricated from waste. Thermal conductivity of bamboo fiber-reinforced composite using polyester resin showed a decrease in thermal conductivity as the fiber volume fraction increased. The lowest thermal conductivity was recorded for fiber volume fraction of 30% and was 0.185 W/mK; this value is 200% higher than what was recorded in our study [22]. In other study, cotton, bamboo, and wool fibers were used as a reinforcement fibers with polyurethane (PU) resin to improve the thermal properties. Results showed significant decrease in the thermal conductivity as the natural fiber was introduced to the PU matrix, whereas the thermal conductivity of the pure PU resin was 0.0425 W/mK and the thermal conductivity of the PU/wool was 0.0370 W/mK [23].

Tetra Pak (core)/woven fabric (skin)

Thermal conductivity and thermal resistance results of Tetra Pak composite and Tetra Pak as a core with different fabrics (glass, jute, and nonwoven) as skin are shown in Table 4. Results revealed that Tetra Pak/glass composite and Tetra Pak/jute composite recorded the highest reduction in thermal conductivity compared to Tetra Pak and Tetra Pak/nonwoven composite. Introducing glass woven fabric as skin layers to the Tetra Pak reduced the thermal conductivity by 8.5% compared to plain Tetra Pak composite. These results are lower than what was presented by [15], whereas a composite of wood-based sandwich were developed with an average thickness of 96 mm.

Table 4.

Thermal conductivity values of Tetra Pak® sandwich composites.

	Samples	Thickness (mm)	Thermal conductivity (W/mK)	Reduction in thermal conductivity (%)	Percent difference (%)
1	TP	5.68	0.06020 ± 0.0005	–	0.32
2	PP-TP-PP	5.53	0.06175 ± 0.001	−2.57	0.31
3	J-TP-J	6.95	0.05615 ± 0.0008	6.73	0.56
4	J-PP-TP-PP-J	6.48	0.06009 ± 0.001	0.18	0.10
5	PP-J-TP-J-PP	5.49	0.05951 ± 0.001	1.15	0.36
6	G-TP-G	6.15	0.05511 ± 0.0005	8.46	0.57
7	G-PP-TP-PP-G	5.84	0.05710 ± 0.001	5.15	0.22
8	PP-G-TP-G-PP	5.33	0.05810 ± 0.001	3.49	0.63

However, when PP nonwoven fabric was used as an additional thermoplastic layer in order to enhance the adherence between the glass woven fabric and the Tetra Pak, thermal conductivity reduced by 5.15% when PP nonwoven fabric located between Tetra Pak waste and glass woven fabric. But the thermal conductivity reduced by 3.5% when PP nonwoven located used as top and bottom layers as shown in Figure 6. This may attribute to the fact that the PP has a higher thermal conductivity than glass fiber [24,25]; therefore, when PP located on the very top layer it facilitates the higher amount of heat to transfer throughout the thickness.

Figure 6.

Thermal conductivity of Tetra Pak® waste (core)/woven fabric (skin) composite.

On the other hand, 6.7% reduction on thermal conductivity occurred when jute woven fabrics were used as skin layers. As the jute fabric has low thermal conductivity, adding top and bottom layers of jute fabric caused a significant effect on reducing the thermal conductivity of the composite material. This agrees with the finding of Vigneswaran et al. [26]. According to them as the ratio of jute increases the thermal conductivity decreases. Using PP nonwoven caused an increase in the thermal conductivity of Tetra Pak/jute fabric. Sample of Tetra Pak with two layers of PP nonwoven showed a 2.5% increase on thermal conductivity of Tetra Pak composite. This due to the high thermal conductivity of PP. Absolute thermal resistance results show that Tetra Pak/jute possess the highest thermal resistance of 12.37 K/W among all other samples. The absolute thermal resistance, thermal resistivity, and thermal conductance are shown in Table 5.

Table 5.

Thermal Resistance and conductance values of Tetra Pak® sandwich composites.

Sample ID		Absolute thermal resistance \|R\| = L/kA (K/W)	Thermal resistance R-value = L/K (m²K/W)	Thermal resistivity r = 1/K (Km/W)	Thermal conductance C = 1/R (W/m²K)
6	TP	9.4352	0.0944	16.6113	10.5986
7	PP-TP-PP	8.9555	0.0896	16.1943	11.1664
8	J-TP-J	12.3776	0.1238	17.8094	8.0791
9	J-PP-TP-PP-J	9.1363	0.0914	16.6417	10.9454
10	PP-J-TP-J-PP	9.8135	0.0981	16.8039	10.1901
11	G-TP-G	11.7583	0.1176	18.1455	8.5046
12	G-PP-TP-PP-G	10.7706	0.1077	17.5131	9.2846
13	PP-G-TP-G-PP	9.1738	0.0917	17.2117	10.9006

A comparison in thermal conductivity between Tetra Pak/jute, Tetra Pak/glass fiber, and traditional insulation materials is shown in Figure 7 [27]. This comparison reveals that Tetra Pak composite exhibits the lowest value of thermal conductivity among other traditional insulation materials, whereas Tetra Pak composite is approximately 40% lower in thermal conductivity compared to other materials. Therefore, Tetra Pak waste mixed with wool yarn waste and Tetra Pak as a core material with skin of glass fiber or jute fiber can be used as an efficient insulator materials.

Figure 7.

Comparison between thermal conductivity of Tetra Pak® waste (core)/woven fabric (skin) composite and other traditional wood base materials.

Mohapatra et al. [28] investigated the effect of teak wood particle size and particle ratio in wood/epoxy composite thermal conductivity. And it was found that as teak wood particle size increased the thermal conductivity increased with increasing the wood particle’s ratio. Teak wood particles with 150 µm with 35.9 volume fraction showed the lowest thermal conductivity of 0.139 W/mK (Figure 6). The mechanical and physical properties of the hybrid composite are investigated and will be published later.

Conclusions

Tetra Pak waste was used to fabricate composite material that can be used as an insulator material for buildings. A mixture of shredded Tetra Pak waste and wool fiber waste was pressed under high pressure and temperature to produce the final composite samples. Other group of composite samples were prepared using Tetra Pak waste as a core material and the skin materials were glass fiber fabric, jute fabric, and polypropylene fabric. The results of Tetra Pak waste/wool waste revealed that introducing the wool waste to the Tetra Pak waste enhanced the thermal insulation properties of the final composite samples compared to the composite samples made of plain Tetra Pak waste. Air trapped within the wool fibers enhanced the insulation properties of the produced composite from Tetra Pak waste.

On the other hand, Tetra Pak waste/glass fiber showed 8.5% reduction in thermal conductivity compared to 6.5% reduction when jute fabric used as skin material to the Tetra Pak waste composite. All the above results indicate that Tetra Pak waste can be recycled and converted into composite material that can be reused as an insulator material for buildings.

Footnotes

Acknowledgements

The authors thank EKOPAN Company for providing raw materials. They would also like to thank Kastamonu Integrated Wood Industry and Trade Inc., for providing their testing facilities.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work has been partially funded by Scientific and Technological Research Council of Turkey (TUBITAK) under grant number 21514107-216.01-237755.

References

Shah

. Developing plant fibre composites for structural applications by optimising composite parameters: A critical review. J Mater Sci 2013; 48: 6083–6107.

Ashori

. Wood–plastic composites as promising green-composites for automotive industries. Bioresour Technol 2008; 99: 4661–4667.

Khanjanzadeh

Bahmani

Rafighi

et al.

Utilization of bio-waste cotton (Gossypium hirsutum L.) stalks and underutilized paulownia (paulownia fortunie) in wood-based composite particleboard. Afr J Biotechnol 2012; 11: 8045–8050.

Lykidis

Grigoriou

Barboutis

. Utilisation of wood biomass residues from fruit tree branches, evergreen hardwood shrubs and Greek fir wood as raw materials for particleboard production. Wood Mater Sci Eng 2014; 9: 202–208.

Sassoni

Manzi

Motori

et al.

Novel sustainable hemp-based composites for application in the building industry: Physical, thermal and mechanical characterization. Energy Build 2014; 77: 219–2266.

Siddiqui

Sun

. Automated model generation of knitted fabric for thermal conductivity prediction using finite element analysis and its applications in composites. J Ind Text 2016; 45: 1038–1061.

Rajkumar

Srinivasan

Suvitha

. Natural protein fiber hybrid composites: Effects of fiber content and fiber orientation on mechanical, thermal conductivity and water absorption properties. J Ind Text 2015; 44: 709–724.

Yachmenev

Parikh

Calamari

. Thermal insulation properties of biodegradable, cellulosic-based nonwoven composites for automotive application. J Ind Text 2002; 31: 283–296.

Tetra Pak global site. TetraPak. Tetra Pak International S.A, http://www.tetrapak.com/about-tetra-pak/the-company/facts-and-figures (accessed 24 April 2015).

10.

Tetra Pak. Tetra Pak 2014 sustainability update. Tetra Pak International S.A, http://www.tetrapak.com/environment/sustainability-report (accessed 24 April 2015).

11.

Yılgör

Kartal

Houtman

et al.

Composite boards produced from waste Tetra Pak® packaging materials: Chemical properties and biological performance. BioResources 2014; 9: 4784–4807.

12.

Lopes

CMA

Felisberti

. Composite of low-density polyethylene and aluminum obtained from the recycling of postconsumer aseptic packaging. J Appl Polym Sci 2006; 101: 3183–3191.

13.

Kollmann

FFP

Cote

. Principles of wood science and technology, Berlin: Springer-Verlag, 1968.

14.

Sahin

Altun

. Effect of some chemicals on thermal conductivity of impregnated laminated veneer lumbers bonded with poly(vinyl acetate) and melamine–formaldehyde adhesives. J Forest Faculty 2008; 8: 125–130.

15.

Kawasaki

Kawai

. Thermal insulation properties of wood-based sandwich panel for use as structural insulated walls and floors. J Wood Sci 2006; 52: 75–83.

16.

Zink-Sharp

. Geometric model for softwood transverse thermal conductivity. Part I. Wood Fiber Sci 2005; 37: 699–711.

17.

Kruger

Adriazola

MKO

. Thermal analysis of wood-based test cells. Constr Build Mater 2010; 24: 999–1007.

18.

Kamke

Zylkowoski

. Effects of wood-based panel characteristics on thermal conductivity. Forest Prod J 1989; 39: 19–24.

19.

Wells

Carrington

et al.

Thermal conductivity of wool and wool–hemp insulation. Int J Energy Res 2006; 30: 37–49.

20.

Zhou

Zheng

et al.

An environment-friendly thermal insulation material from cotton stalk fibers. Energy Build 2010; 42: 1070–1074.

21.

Manzi

Sassoni

Motori

et al.

New composite panels with hemp hurds for sustainable buildings. Environ Eng Manag J 2013; 12: 31–34.

22.

Mounika

Ramaniah

Ratna Prasad

et al.

Thermal conductivity characterization of bamboo fiber reinforced polyester composite. J Mater Environ Sci 2012; 3: 1109–1116.

23.

Büyükakinci

Sökmen

Küçük

. Thermal conductivity and acoustic properties of natural fiber mixed polyurethane composites. Tekstil ve Konfeksiyon 2011; 21: 124–132.

24.

Osswald

Baur

Brinkmann

et al.

Properties and testing: international plastics handbook—the resource for plastics engineers, 4th ed. Cincinnati, OH: Hanser Publishers, 2006.

25.

Incropera

DeWitt

Bergman

et al.

Fundamentals of heat and mass transfer, Hoboken, NJ: John Wiley & Sons, Inc., 2007.

26.

Vigneswaran

Chandrasekaran

Senthilkumar

. Effect of thermal conductivity behavior of jute/cotton blended knitted fabrics. J Ind Text 2009; 38: 289–307.

27.

Williamson

Beauchamp

. Insulation solution to enhance the thermal resistance of suspended timber floor system in Australia, Melbourne, VIC, Australia: Forest and Wood Products Research and Development Corporation, 2005.

28.

Mohapatra

Mishra

Choudhury

. Experimental study on thermal conductivity of teak wood dust reinforced epoxy composite using Lee’s apparatus method. Int J Mech Eng Appl 2014; 2: 98–103.

Thermal insulation properties of hybrid textile reinforced biocomposites from food packaging waste

Abstract

Keywords

Introduction

Thermal conductivity

Materials and methods

Manufacturing composites from Tetra Pak waste

Tetra Pak/wool waste fiber

Tetra Pak (core)/woven fabric (skin)

Thermal insulation test

Results and discussion

Tetra Pak/wool waste hybrid biocomposite

Tetra Pak (core)/woven fabric (skin)

Conclusions

Footnotes

Acknowledgements

Declaration of Conflicting Interests

Funding

References