Chitosan X Cellulose
A material combination in an established cycle
Chitosan and cellulose form a material combination that can be recycled in an established material cycle. The solubility of chitosan in acidic solutions fits into the existing processes of waste paper recycling.
This project presents the properties of the material combination developed and documented in experiments. These properties promise new, expanding and supporting capabilities that broaden the portfolio of paper applications.
Four impressive results of the experiments were agreeably staged in DIN A4 format. These can be assigned to the four elements of fire, earth, water and air of our planet and thus stand in special relation to the project orientation: a resource-saving handling of our planet.
full concept text
Chitosan and cellulose form a material combination that can be recycled in an established material cycle. This project presents the properties of the material combination developed and documented in experiments. These properties promise new and supporting capabilities that expand the portfolio of paper applications.
The solubility and separability of chitosan and cellulose are the focus of the project. New material combinations or additives of the processing steps often cause problems in established material cycles and thus lead to the whole product being discarded. This material is lost for further recycling steps. The solubility of chitosan in acidic solutions fits into the existing processes of waste paper recycling.
Chitin, the raw material of chitosan, is the second most abundant biopolymer in nature after cellulose. It can be found in the exoskeletons of shellfish or insects or in fungi. The polysaccharide is used to form structures. Chitin is currently extracted from crab shells in Asia. A local, alternative source is provided by maggot farming. Here, the pupae of the black soldier fly can be used. In the first step, the chitin is extracted from the shells and pupae using acids and alkalis. In the process, proteins, lime and dyes are washed out. Further processing steps neutralize the chemicals used, making them ecologically safe. Deacetylation turns chitin into chitosan. Through this chemical process, powders or granules with different concentrations and properties can be produced as required. Chitosan has numerous special properties that offer great potential for a wide range of applications. The material owes many of these properties to its positive charge, which contrasts with the negative charge of many other natural substances.
The cellulose used for paper production is obtained from trees that are mostly cleared in Latin American and Asian countries. The cellulose fibres are processed with the use of a tremendous amount of water and chemicals before they can be added to the papermaking process.
Chitosan and cellulose are processed into paper with further additives. Various products are manufactured from these semi-finished products. After a comparatively short utilization phase, paper products are collected via the domestic disposal route and fed to local waste paper recycling plants. Here, cardboard, paper and foreign materials are separated each other. The paper is shredded and defibred in water. With the help of caustic soda, colour particles are foamed out of the pulp. Here, a further bath in an acidic solution can dissolve the chitosan from the cellulose. This way, the cellulose and the chitosan can be separately added back to the paper production cycle.
In this project, a wide variety of properties of the material combination were worked out through wide-ranging experiments. Four impressive results of these experiments were staged agreeably in DIN formats. The accessories used in the individual stagings provide an outlook on possible applications and convey the haptics and properties.
By applying chitosan, the paper stops burning, draws water more slowly and retains its shape when wet. With a localized application of chitosan, the chitosan contracts during the drying process and has a shaping effect on the paper. Chitosan makes the paper impermeable to air and allows it to be glued.
The four selected properties can be assigned to the four elements of fire, earth, water and air of our planet and are thus in special relation to the project orientation: a resource-saving handling of our planet.