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In recent years, biocomposites have gained increasing attention in both industry and academia as a promising sustainable alternative to conventional composites. While the application range of biocomposites is continuously increasing, they are still very little used as food contact materials. The aim of the present study was to investigate the suitability of viscose fibres as reinforcement in thermoplastic biocomposites intended for food contact applications. Viscose fibres were compounded into biobased high-density polyethylene (HDPE) using a co-rotating twin-screw extruder and test specimens were injection moulded. Biocomposites were prepared using untreated and pelletized viscose fibres and the effect of the addition of compatibilizer and lubricant was investigated. Morphological, mechanical, rheological and migration properties of the prepared samples were characterised. Untreated fibres exhibited a significantly higher reinforcing effect than pelletized fibres due to better dispersion. The addition of a compatibilizer resulted in enhanced interfacial adhesion and fibre dispersion, which was reflected in increased tensile strength. The overall migration of all studied compositions was well below the permitted level, while the addition of a compatibilizer resulted in a strong acidic flavour in sensory tests, which is not permissible in food contact applications. The results showed that viscose fibres are a promising candidate for the preparation of thermoplastic biocomposites for food contact applications.

Plastic injection moulding is one of the most commonly used manufacturing processes applied to produce plastic products. The process is relatively energy efficient, since it takes less energy to melt or soften plastics than it does metals. However, injection moulding is a multifaceted process which has many variables that many forget to account for. This may lead to financial losses and a larger environmental impact than necessary. This paper is a brief introduction of the steps we at Plastika Skaza take and the tools, we use to ensure that our product have a minimal environmental impact. We have taken our Bokashi Organko 2 as a case study to present the actions we took during the products life time, from first concepts to active production. By using Computer aided simulations, modern machinery, recycled materials and statistical methods, such as the design of experiments, Taguchi model and Life cycle impact assessment, we achieved an average reduction of 39,4 % in the products environmental impact.

V diplomskem delu smo se posvetili izboljšanju tehnološkega procesa izdelave kartona. Eksperimentalno raziskavo smo opravili v realnem okolju kartonažne tovarne skozi daljše obdobje. S povečanim deležem uporabe recikliranih vlaken ter z uvajanjem zaprtih krožnih procesov papirna industrija sicer zmanjša stroške in vplive na okolje, vendar so to tudi glavni vzroki za povečanje mikrobiološke aktivnosti. Kakovost kartona se zmanjša zaradi prisotnosti mikroorganizmov, ki povzročijo nihanja pH vrednosti in neenakomerno raztapljanje CaCO3, ki se zadnje čase vedno bolj uporablja tudi kot polnilo. Izsledki raziskave so pokazali, da se z uvajanjem CO2 v papirno pulpo stabilizirajo pogoji za ohranjanje karbonatnega ravnotežja v mokrih fazah, posledično se zmanjša mikrobiološka aktivnost in poraba kemikalij, stabilizira se pH vrednost vse skupaj pa pripomore k zanesljivejši proizvodnji in boljši kakovosti izdelka. In the dissertation we focused on the improvement of technological process in cardboard production. The experimental research was performed in realistic environment of cardboard factory through longer period. Using increased share of recycled fibres and by introducing of closed circular processes, the paper industry reduces costs and impacts on the environment however, these are also the main causes for microbiological activity enlargement. The quality of paperboard is reduced due to the presence of microorganisms, which cause changes in pH values and uneven dissolving of CaCO3 that is nowadays increasingly used as a filler. The research results indicated, that the introduction of CO2 to paper pulp stabilizes the conditions for keeping the carbonate equilibrium in wet phases constant. Consequently, the microbiological activity and consumption of chemicals is reduced, and pH value is stabilized all this contributes to more reliable production and better product quality.