Peanut Husk Panels for Use in Architecture and Design

The peanut husk panels are the result of a study involving research, development and innovation. Through a research and development agreement with the company Maglione Hnos y Cia SA, the support of the Ministerio de Ciencia Tecnología e Innovación productiva (MINCyT) and the Ministerio de Ciencia y Tecnología in the province of Córdoba, the project has achieved serial production of the panels at pilot scale. The next stage consists of scaling up the production of the panels for their eventual commercialization.
 
The Argentinian Peanut is grown mainly in the center and south of the province of Córdoba, where the agroecological conditions are optimal for their development. 95% of the country’s total peanut crop is produced and processed in Córdoba. Their quality is widely recognized and demand for the Argentinian peanut is highest in the US and Europe. The production of peanuts in Córdoba currently stands at over 1,000,000 tons per year. However, only a small quantity of this is sold in the domestic market, with over 95% of total production being exported.
 
Córdoba’s success in the development of this agro-industrial specialty can be explained by the quality of the soil and the presence of the processing plants. No fertilizers, and only minimal quantities of agrochemicals, are used on the crops. In addition, crop rotation with soybean, corn and pastures helps to preserve soil health and maximize yields.
 
The husks account for 30% of the total weight of the peanut in-shell. Their removal is the first process the peanuts undergo on entering the selecting and processing plant. This creates a concentrated overabundance of husks, which have no applications on a scale similar to that of their production.
 
Peanut Husks
Agriculture is one of the pillars of the Argentinian economy. There is well developed seed-processing technology, with emphasis placed on its performance.
 
Seed and grain husks are not highly valued. In general, nature takes care of things: their biodegradable properties mean they can be used to improve the soil.
 
There is a difference when it comes to peanut husks, however. They are the natural containers of seeds which grow below ground. The properties that nature designed to protect the peanut seed while it is growing are the same properties which mean they do not easily biodegrade.
 
Evidence of this is frequently seen in the areas surrounding selecting and processing plants, where husks pile up year after year. In large quantities, they harm the soil and pollute the area around the plant and can even pose a fire risk.
 
The first process that the in-shell peanut undergoes on entering the processing plant is the separation from the husk, the by-products of which are husks and seed coatings. The added benefit of this process is that these by-products are removed in such a way that allows them to be easily retrieved and suitable for use as raw material.
 
This means we find ourselves with an overabundance of plant material with particular characteristics: concave convex, with a rigid structure, porous surface, and very light.
 
Some characterization tests were carried out. When magnified, the peanut husks were observed to be composed of a triple-layered structure, in which the rigidity is provided by the inner shell. A fibrillar mesh covers the inner shell, providing strength. On the surface, a thin skin covers the mesh to protect it and keep it stuck to the inner shell.
 
They are highly water-absorbent, a process which produces a brown substance with a high tannin content. The botanical composition of the husks is cellulose, hemicellulose and lignin, with a high proportion of lignin compared to other plant fibers, a lower hemicellulose content and a higher amount of lignin.
 
Panels Made from Peanut Husks
The aim of this project, led by Doctor Gatani for the past 10 years, was to develop a new material which would serve as an alternative in architecture and design, a sector which generates a demand for large quantities of materials.
 
The result of the material made with peanut husks as the main aggregate was volatile-organic-compound (VOCs)-free polymer-based agglomerated panels.
 
The incorporation of the husks, without grinding and without any chemical treatment, was sufficiently compatible with the resin. The result was a material with properties similar to those of industrialized wooden panels. The production process is based on the wood industry.
 
The particles are passed over a double sieve in a rotary tumbler in order to eliminate dust particles and foreign matter. They are then combined with polymeric resin in an industrial mixer to obtain the final mixture from which the panels will be made.
 
Molding involves combining high pressure and high temperature for a few minutes. The result is agglomerated sheets which are aesthetically attractive due to their textures and natural colors, e.g., ochres, browns, copper browns and yellows.
 
The use of these by-products on their elimination from the production chain allows us to achieve a texture which looks rough but is smooth to the touch, and in which we can see the shapes and sizes of the husks, as well as some stems and leaves from the peanut plant.
 
The physical and mechanical properties achieved are similar to those of wood fiberboard, with a density of around 800 kg/m3 and a modulus of rupture of up to 10 MPa. Given these characteristics, this material is recommended for non-load-bearing applications. As with industrialized wooden sheets, they should be protected from exposure to moisture.
 
Architecture and Design
In order to validate the empirical and scientific experiments carried out on the resulting materials, the panels were used in experimental applications in architecture as well as object and furniture design. The designs were produced by professional architects and industrial designers who formed part of the work group. Funding for the project was provided through successive investigation, development and innovation projects in Argentina.
 
Partitions, ceilings and dividing panels have been developed with the aim of demonstrating the panels’ suitability as a sustainable concept in the definition and design of spaces and their finishes.
 
Offcuts were used to make a number of small objects such as pencil cases, card holders, chair seats, cup holders, clipboards, picture frames and trays.
 
What remains is the final stage of the project: applying the results achieved for use in industry.