PAPER-LIKE AND NANOCOMPOSITE MATERIAL BASED ON MINERAL FIBER

Abstract

The paper-like nanocomposite material can be used as capillary-porous elements of evaporative-type air-cooling units. As mineral fibers, glass fibers with a diameter of 0.4 μm are used. These fibers are hydrophilic; they do not swell and have a large specific surface area. As a binder, sodium aluminate and aluminum sulfate are used at a predetermined ratio.

Description

Paper-like nanocomposite material based on mineral fibers for evaporative-type air-cooling units.

The invention is related to the field of paper-like composite materials and can be used as capillary-porous elements of evaporative-type air-cooling units.

There is a capillary-porous material that is well-known that contains glass fibers with a diameter of 0.2 μm and an inorganic binder (patent RU 2478747 C2, 16 May 2011). This invention uses mineral fibers of various diameters and nature, that provide a capillary-porous structure, while the strength is regulated by the amount of binder.

The closest analogue is a paper-like material made of glass fibers of 0.25 μm in diameter, using aluminum salts and polyvinyl acetate emulsion (PVAE) as binder, with the addition of polyvinyl alcohol fibers (PVA), (patent RU 2425919 C1, 15 Apr. 2010).

The aim of the invention is to provide a paper-like nanocomposite with a hydrophilic capillary-porous structure in order to provide high absorbency, moisture capacity, size invariance (no swelling or warpage) and resistance to mold, fungi, and microorganisms of the aquatic environment, non-toxic and with a technological strength enough to be processed into various wares.

To achieve this goal, a series of research work was carried out with the subsequent production of an experimental batch of material. The casting of the material was carried out according to a conventional paper-based molding technique on a LOA-2 sheet paper machine. The experimental lot was made on “Voit” paper machine, and introduced into the production of energy-saving, environmentally friendly evaporative-type air-cooling units.

Glass fibers with a nominal diameter of 0.4 μm were used as mineral fibers. These fibers are hydrophilic and at the same time they do not swell and have a large specific surface, which is important when forming a thin capillary-porous structure in the process of forming a sheet. In contrast to fibers of plant origin, mineral fibers do not have the bonding ability. To provide bonding, a measured amount of sodium aluminate solution (NaAlO2) with a pH of 12 was added to the composition. The formation of polynuclear complexes was provided by measured addition of aluminum sulfate (Al2 (SO4)3) solution with medium pH of 3.

As a result of the hydrolytic reaction, polynuclear complexes are formed that can react with functional groups located on the surface of the fiber with the formation of a coordinate bond—in particular, a hydrogen bond. The resulting polynuclear complexes provide strength, and also synergize the fine capillary-porous structure of the material formed by Ø 0.4 μm glass fibers. Active regulation of the pH of the medium, achieved by changing the ratio between the amounts of NaAlO2 and Al2 (SO4)3, makes it possible to obtain polynuclear complexes with different reactivity and dimensionality. The reactivity provides the strength characteristics and the dimensionality guarantees a thin capillary-porous structure. This method of introducing and forming a binder when molding the material makes up the claim for novelty of the invention.

As a result of the experimental production, the material with the following ratio of components by mass (%) was obtained:

Ø 0.4 μm glass fiber—70%

NaAlO2—5-25

Al2(SO4)3—5-25

With properties presented in Table 1 and differing from those known in blend composition and higher characteristics in height and time of water rise, moisture capacity and strength.

Table 1 gives examples of material compositions and their properties

	TABLE 1
	Compositions
		Ø 0.4 μm glass	Ø 0.4 μm glass	Ø 0.4 μm glass
		fiber - 70%	fiber - 70%	fiber - 70%
		NaAlO2 - 5%	NaAlO2 - 15%	NaAlO2 - 25%
No.	Properties	Al2(SO4)3 - 25%	Al2(SO4)3 - 15%	Al2(SO4)3 - 5%
1	Mass 1 sq. m, g	100	100	100
2	Thickness, mm	0.5	0.5	0.5
3	Maximum water rise	400	500	400
	height with vertical
	position of the plate
	at 20° C., mm
4	Water rise time with	10	6	8
	vertical position of
	the plate and a height
	of up to 180 mm at
	20° C., min
5	Moisture capacity, %	600	700	600
6	Breakdown force in	8	10	8
	machine direction, H

Due to its inorganic nature, the material is characterized by its thermic, chemical and biological stability, absence of toxicity and zero emission of harmful substances into the air, resistance to mold, fungi and microorganisms in the aquatic environment.

Based on the data contained in the table, the presented materials have better characteristics compared to their analogs and can be used as capillary-porous elements in evaporative-type air cooling units.

The presence of a nanoscale binder in the composition, which is confirmed by electron microscopy (FIG. 1), as well as the significant effect of same on the properties of the material, gives the right to assert that the production of these materials belongs to the realm of nanotechnology.

Claims

1. Paper-like nanocomposite material based on mineral fibers using NaAlO2 and Al2 (SO4) 3 as binder made on paper making equipment using casting technique and characterized by its blend composition and higher characteristics in height and time of water rise, moisture capacity and strength, with the following ratio of components, mass. %: Ø 0.4 μm glass fiber—70%Sodium aluminate NaAlO2—5-25 (by Al2O3)Aluminum sulfate Al2(SO4)3—5-25 (by Al2O3)