**3.6 Thermal analysis**

The decomposition temperatures (Td) for LDPE and LDPE nanocomposite were obtained by thermogravimetric analysis (TGA). Samples (10 mg) placed in

**145**

decomposition [24].

using melt mixing technique.

cal to that inside the glass greenhouse.

**4. Conclusion**

**Figure 11.**

the LDPE matrix.

*Nanosilica Composite for Greenhouse Application DOI: http://dx.doi.org/10.5772/intechopen.92181*

an alumina holder were submitted to a heating cycle at a rate of 10°C/min starting

**Figure 11** shows the decomposition profile (percentage of weight loss with temperature) for LDPE and LDPE/silica nanocomposites performed in one step. The presence of SiO2 in the nanocomposite confers thermal stability to it shown by the continuous shifting of the curve to higher temperatures as the SiO2 content increased. These results may be attributed to the silica layers acting as an insulator and a barrier to mass transport from volatile substances generated during the

Throughout this study, silicon dioxide films with different ratios (0.5, 1, 2.5, 5, 7.5, and 10 wt% SiO2) were mixed with low-density polyethylene (LDPE) polymer,

The effect of incorporation of 0.5–10 wt% of silica particles to a tensile property of LDPE matrix was investigated. The results showed that the addition of 1 wt% of nanosilica has successfully enhanced the tensile and elongation at break of the nanosilica-filled LDPE material. The incorporation of >1 wt% of nanosilica particles had caused agglomeration and uneven distribution of the particles throughout

These LDPE/silica nanocomposites were used to build a mini greenhouse. SiO2 reduces the transmission of radiation near 9 μm and allows the transmission of the ultraviolet and visible radiations to pass through them during daytime (period of sunshine, without being exposed to direct sunshine.) Thus, we were able to preserve the thermal radiation of the ground by raising the internal temperature of the greenhouse up to more than 2°C than that of the same greenhouse without mixing. The temperature inside the LDPE/silica greenhouse was found to be almost identi-

from room temperature (25°C) up to 600°C, under nitrogen atmosphere.

*TGA curves of neat LDPE and LDPE/SiO2 nanocomposites under nitrogen flow.*

*Nanosilica Composite for Greenhouse Application DOI: http://dx.doi.org/10.5772/intechopen.92181*

*Composite and Nanocomposite Materials - From Knowledge to Industrial Applications*

sampled by this technique do not yield an average picture of the sample. Also, transmission electron microscopy (TEM) is better suited than SEM for studying

*Scanning electron micrograph of nanocomposite LDPE 2.5 wt% SiO2 sample at ×2000 magnification.*

The decomposition temperatures (Td) for LDPE and LDPE nanocomposite were obtained by thermogravimetric analysis (TGA). Samples (10 mg) placed in

**144**

**Figure 10.**

**Figure 9.**

*Transmittance at 9 μm as a function of different ratios of SiO2.*

nanoparticle dispersion [9].

**3.6 Thermal analysis**

**Figure 11.** *TGA curves of neat LDPE and LDPE/SiO2 nanocomposites under nitrogen flow.*

an alumina holder were submitted to a heating cycle at a rate of 10°C/min starting from room temperature (25°C) up to 600°C, under nitrogen atmosphere.

**Figure 11** shows the decomposition profile (percentage of weight loss with temperature) for LDPE and LDPE/silica nanocomposites performed in one step. The presence of SiO2 in the nanocomposite confers thermal stability to it shown by the continuous shifting of the curve to higher temperatures as the SiO2 content increased. These results may be attributed to the silica layers acting as an insulator and a barrier to mass transport from volatile substances generated during the decomposition [24].

### **4. Conclusion**

Throughout this study, silicon dioxide films with different ratios (0.5, 1, 2.5, 5, 7.5, and 10 wt% SiO2) were mixed with low-density polyethylene (LDPE) polymer, using melt mixing technique.

The effect of incorporation of 0.5–10 wt% of silica particles to a tensile property of LDPE matrix was investigated. The results showed that the addition of 1 wt% of nanosilica has successfully enhanced the tensile and elongation at break of the nanosilica-filled LDPE material. The incorporation of >1 wt% of nanosilica particles had caused agglomeration and uneven distribution of the particles throughout the LDPE matrix.

These LDPE/silica nanocomposites were used to build a mini greenhouse. SiO2 reduces the transmission of radiation near 9 μm and allows the transmission of the ultraviolet and visible radiations to pass through them during daytime (period of sunshine, without being exposed to direct sunshine.) Thus, we were able to preserve the thermal radiation of the ground by raising the internal temperature of the greenhouse up to more than 2°C than that of the same greenhouse without mixing. The temperature inside the LDPE/silica greenhouse was found to be almost identical to that inside the glass greenhouse.

Statistically speaking the conclusions are acceptable because the experiment was replicated many time. The main gain is the fact that the LDPE/silica greenhouse has the same temperature as the glass-made greenhouse.
