Browsing by Subject "puukuitu"

Absorption panels are utilized in public spaces to improve the acoustic properties of the space and to reduce reverberation. Porous materials such as glass wool, mineral wool or polyester based batts are commonly used as sound absorption panels. However, they are generally harmful for environment and difficult to dispose. By foaming cellulose, water and soap, it is possible to form an environmentally friendly porous fiber material, which has the same sound absorption capacity as mineral wool. The purpose of this study is to investigate how the physical and chemical properties of the fiber affect the absorption capacity of the foam-formed pulp panel. The purpose is to find properties that increase the sound absorption ca-pacity. The raw materials used in the study were hardwood and softwood kraft pulp from different bleaching stag-es and dissolving pulp. There were eight pulps with different properties. The softwood pulps were made of pine and the hardwood pulps were made of birch. The pulp was examined for fiber length and width, spe-cific fiber surface area, chemical composition, pore size distribution and average pore diameter. A foam-forming technique was used to prepare the samples, in which the pulp was foamed with water and a surfac-tant. The foam was placed on a water-permeable metal mesh in a mold and dried. The result was a light and porous fibrous panel. Samples were cut from the panels and the sound absorption coefficient was measured using an impedance tube. The study noticed that the density of the sample had a significant effect on the absorption coefficient. Samples with different densities were difficult to compare. On average, the higher the sample density, the higher the sound absorption coefficient. However, the absorption coefficients dissolving pulps were high despite their low densities. The effects of the measured properties of fibers were difficult to determine be-cause it was not known whether the absorption coefficient was affected by measured property or by anoth-er property that was not considered in this study. There were no significant differences in the absorption coefficients with the samples of the same density. According to the results of this study, fiber length and width, chemical composition and the surface area of fibers do not have significant effect on the ability of the cellulose panels to absorb sound. Dissolving pulp had the highest absorption coefficients and the lowest density. By increasing the density of dissolving pulp it’s the absorption coefficient can be raised above the absorption coefficient of glass wool.

The gastrointestinal tract of the ruminants is specialized to utilize fibre as a main source of energy. Cellulose and hemicellulose from grasses typically compose a considerable part of the feeding of ruminants but wood-based feed ingredients are not commonly used. The competition about land use between food and feed production is a global challenge which increases the interest towards novel feeds. Microcrystalline cellulose (MCC) has many applications in food and pharmaceutical industry. Rumen microbes have been able to utilize MCC in vitro which made it reasonable to expect that they could be used as feed for ruminants. The aim of this in vivo experiment was to investigate the effects of MCC on intake, rumen fermentation, milk production and diet digestibility in dairy cows. This experiment used three total mixed rations (TMRs) which included MCC 0, 10 or 100 g/kg DM (MCC0, MCC10, MCC100). In MCC10-diet MCC was added to control diet and in MCC100 diet MCC replaced rolled barley. The ratio of silage and concentrates in TMR was 50:50 and cows were fed ad libitum. 24 multiparous Nordic Red cows were used in the experiment. Six of the cows were rumen cannulated. The experiment consisted of two 21-day periods. Data and samples were collected during the last seven days of the periods. The NDF content in MCC was very high (937 g/kg DM) but crude protein content (12,5 g/kg DM) and organic matter in vitro digestibility (0,404 g/g) were low. Feed intake of the cows was on average 25.6 kg DM/day and there were no significant differences between the diets. The digestibility of NDF increased in MCC100 diet (p<0.001). The digestibility of organic matter and dry matter were not significantly affected by the diet. Inclusion of MCC decreased the energy corrected milk production of the cows about 1.5 kg/day and it decreased also the fat and protein content of the milk (P<0.05). These differencies were however numerically small. Based on the results of this study MCC can be added on the diet of dairy cattle without negative effects on the feed intake but when replacing rolled barley it deacreases slightly the production of the energy corrected milk. Positive effects of MCC on the rumen fermentation could not be demonstrated under circumstances of this experiment.

In the literature study paper manufacturing process and modification of wood fiber-based packaging materials were reviewed. The aim was to understand the properties of polyurethane (PU) and its suitability as an additive in fiber-based food packaging material. Also possibility of migration from food packaging materials and methods of migration analysis were reviewed. The aim of the experimental work was to examine if diisocyanates, phthalates or other substances migrate significantly from PU-impregnated wood fiber-based packaging material to cheese. The impact of storage conditions such as temperature, relative humidity (RH) and storage time on migration were examined. The base of the sample package was made of PU-impregnated fiber material (VTT Oy, Finland) and the cover film was BoPET/PE/PA/EvOH/PE-laminate (Wipak Oy, Finland). Slices of pasteurized hard Cheddar cheese (Wyke Farms Mature Cheddar, England) were packaged as samples. Migration was measured from the surface of the packaging materials and cheese using attenuated total reflection Fourier-transform infrared spectrometer (ATR-FT-IR) and from the head space of the samples using solid-phase microextraction coupled with gas chromatography and mass spectrometer (SPME-GC-MS). No diisocyanates were detected in any packaging material or cheese samples with either methods. A notable peak in the mass spectra of samples containing or having been in contact with PU was caused by 1,6-dioxacyclododecane-7,12-dione. Also one phthalate, diethyl phthalate (DEP) was detected with SPME-GC-MS in some of the samples. The peak areas of DEP decreased after two weeks storage at 10 °C, RH 56 % and 5 °C, RH 90 %, except for cheese. After four weeks storage under the warmest conditions (10 °C, RH 56 %) the peak areas increased for all the samples but decreased at the highest RH (90 %) for PU-fiber and the cheese in it. DEP was detected in almost every cheese sample packed in PU-fibre. DEP was also detected in fiber without PU. No diisocyanates or phthalates classified as harmful to human health were detected in this study. Based on the results of this migration study PU-impregnated fiber material would be safe to use in contact with food.