(ORDO NEWS) — NUST MISIS scientists, together with colleagues from the Federal University of Technology in Akura (Nigeria), have developed a new technology for manufacturing building composites and slabs based on them.
Vegetable waste from coconut and hibiscus fibers provided the new material with increased moisture resistance and strength, which will be especially in demand in residential construction.
The results of the work were published in the international scientific journal Environmental Science and Pollution Research. Waste recycling is the most important task of “green” chemistry.
They are raw materials for creating materials that purify wastewater, extract metals, pigments, and are also used in the production of building materials such as gypsum, road surfaces, and so on.
Cement boards are composites made from recycled paper and cement as a binder. These types of material can be used for wall and ceiling cladding , as well as replacing expensive chipboard (chipboard) in furniture production.
The paper in the composition of waste paper has good heat and sound insulation, it is cheap to use and requires a minimum of energy during processing, which allows it to be classified as an environmentally friendly material.
However, having a high surface porosity, the paper pulp is prone to abundant absorption of moisture from the air, which greatly impairs the functional properties of cement boards.
NUST MISIS researchers, together with colleagues from the Federal University of Technology in Akura, solved this problem by using coconut shell powder and kenaf (hemp hibiscus) as a paper pore filler.
Microstructure of fibers with different percentages of plant fiber
“The purpose of incorporating fibers into the cement material was to increase its strength and plasticity. In addition, fibers are included to reduce the initiation and propagation of cracks and to evenly distribute stress in the composite matrix.
We mixed kenaf fiber in various proportions with 20 percent cement and the same amount of coconut shell powder, while the rest of the composition was paper pulp.
The obtained samples of composites were kept for 14, 28 and 90 days and the mechanical properties were studied.
The results showed that a fiber dosage of two percent optimally improved the adhesion strength and screw holding force compared to the control mixture,” said Valentin Romanovsky, co-author of the study, leading expert at the Research Center for Structural Ceramic Nanomaterials of NUST MISiS.
Scheme of composite production technology
According to the developers, natural plant fibers are light, very cheap and have high strength and ductility. The waterproof fiber of kenaf, a well-known spinning culture, like jute fiber, is suitable for the manufacture of packaging fabrics and bags, carpets and tablecloths, for the manufacture of paper and cardboard.
The addition of kenaf fiber in a percentage mass of 1-3 percent provided an increase in the elastic modulus of the composite, and hence the strength of the final building boards.
In a previous study, the authors showed that even a 10% addition of coconut shell powder can be successfully used as a pore filler in a composite, reducing its “moisture permeability” compared to controls. Currently, the scientific team is completing a series of laboratory tests in order to optimize the developed technology.
Contact us: [email protected]