*3.2.4 Water absorption*

As shown in the **Table 6** the filler content has a notable effect on water absorption. After 24 h of immersion in water, the lowest water absorption rate was reached with a load proportion of 10%. The incorporation of cocoa shell powder would be help to increase the percentage of water absorption up to a certain content, which means that more hydrogen bonds are formed between the water molecules and the OH group present in the powders. Similar results were observed by Huner et al. who reported that the rate of water absorption increased with increasing fiber content [29, 30]. This could be explained by the formation of a less surface interaction between the matrix and the powder during mixing, resulting in a higher water absorption [31]. In addition, PET would constitute an ideal binder for the compaction of this powder and reduce water absorption. This low water absorption value could improve the physicomechanical properties.

#### **3.3 Chemical stability**

As shown in **Table 7** that after 10 days of impregnation in acidic medium and neutral medium, the composite material undergoes a mass loss of 8 and 2%, respectively, whereas in a basic medium no loss is observed. This result reflects the good chemical stability of the composites under extreme conditions and shows that the material can indeed be applied as a tile coating for the walls of toilets and showers.

## **4. Conclusion**

The chapter studied the chemical stability and mechanical properties of bathroom wall composites manufactured from recycle polyethylene terephthalate mixed with cocoa hull powder. Organosolv treatment of cocoa powder hulls enhanced the quality of the cocoa powder hulls by removal of hemicellulose and lignin thereby increasing the cellulose composition. The Organosolv treatment gave a more thermally stable composite material. The addition of cocoa powder hulls produces an environmentally friendly material. It is clear that cocoa powder hulls have great potential as a filler and reinforcement for composites requiring similar properties to PET. The recycled PET/30% cocoa hull powder blend has higher tensile, flexural, and impact strength compared to other blends. Recycled PET/30% cocoa hull powder blend was also found to have good properties in terms of stability. The manufactured composites showed improved mechanical properties with respect to the powder content increase, showing the reinforcement potential of cocoa powder. It is thus possible to consider a prospective industrial use of this agricultural waste, for instance, for the manufacture of bathroom wall tiles in construction industry in Cameroon.

*Mechanical Properties and Chemical Stability of Bathroom Wall Composites Manufactured… DOI: http://dx.doi.org/10.5772/intechopen.102457*
