The aim of this thesis was to prepare a polylactic acid, nanofibrillated cellulose and
Pinus sylvestris extract based composite. First, we performed the Soxhlet extraction with different solvents (cyclohexane, acetone, ethanol) to obtain a wet extract, which we then rotavaped to produce a dry extract of Scots pine knot wood. We performed chemical analysis of extract (gravimetric method, high performance liquid chromatography (HPLC), UV – Vis spectrophotometry). We then lyophilised the nanofibrillated cellulose, mixed it with chloroform and homogenized the mixture. Lastly, we prepared the polylactic acid. We mixed the components to obtain the desired composites. We performed a scratch test after 40 days. We expected the nanofibrillated cellulose to improve the mechanical properties and the extractives to impair them, which has not proved to be entirely correct. The addition of nanofibrillated cellulose worsened the mechanical properties oh the PLA polymer. Extract combined with nanofibrillated cellulose improved the properties of film in some cases, while it did not produce a better resilience against scratching in others. The most resilient was the PLA and extract based composite, while the one made of PLA, extract and 2 % freeze dried nanofibrillated cellulose proved to be the least resilient.
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