Biodegradable Composites and Their Application in Agriculture

Darbo objektas – bioskaidūs kompozitai iš krakmolo, techninio glicerolio ir rapsų išspaudų. Darbo tikslas – iš krakmolo ir biodyzelino gamybos metu susidarančių šalutinių produktų – techninio glicerolio ir rapsų išspaudų – pagaminti kompozitus, tinkamus vienkartinių indų, skirtų augalams auginti, gamybai. Darbo metodai – biokompozitų plėvelių mechaninių savybių tyrimui naudota universali bandymų mašina ZWICK/ROELL BDO-FBO.5TH. Sorbcinės savybės, tirpumas vandenyje, pralaidumas vandens garams, dirvožemio drėgmė, pH tirti remiantis standartizuotais metodais. Plėvelių bioskaidumas nustatytas pagal bandinių apaugimą mikroskopiniais grybais (Paecilomyces variotii, Penicillium sp., arba Trichoderma virens) 5 balų sistema. Darbo rezultatai. Iš krakmolo, rapsų išspaudų ir gryno glicerolio pagaminti žemės ūkio paskirties kompozitai, iš jų išlietos plėvelės ir ištirtos jų savybės. Mechaninių savybių tyrimai parodė, kad didėjant išspaudų kiekiui plėvelėse, jų atsparumas trūkimui proporcingai mažėja, o elastingumas didėja. Didžiausias santykinis pailgėjimas nutrūkimo momentu būdingas plėvelėms, kuriose krakmolo ir rapsų išspaudų masės santykis – 6:4, 5:5. Plėvelių tirpumas vandenyje gerėja didėjant rapsų išspaudų kiekiui jose. Esant krakmolo-rapsų išspaudų masės santykiui 4:6, plėvelių tirpumas vandenyje padidėja iki 38,8 %. Rapsų išspaudų kiekis plėvelėse, jų higroskopiškumui esminės įtakos neturi. Plėvelių prisisotinimo vandens garais laipsnis esant 100 % aplinkos drėgmei, siekia 45 %. Techninis glicerolis krakmolo-rapsų išspaudų plėvelių plastifikavimui tinka tik naudojant jį kartu su karbamidu. Optimalus techninio glicerolio ir karbamido masės santykis jose – 3:0,2-3:0,6. Vienkartinių indų formavimui labiausiai tinka plėvelės, kuriose krakmolo, rapsų išspaudų, techninio glicerolio ir karbamido masės santykis yra 4:6:3:0,4. Iš šios sudėties plėvelių pagaminti indeliai augalams, ištirtos jų eksploatacinės savybės atliekant vegetacinius bandymus. Krakmolo-rapsų išspaudų indelių mechaninės ir eksploatacinės savybės lyginant su šiuo metu naudojamais pramoniniais durpiniais indeliais yra geresnės. Jie tvirtesni ir elastingesni, mažiau laidūs vandens garams. Esant aukštai aplinkos oro temperatūrai, dirvožemio drėgmės ir temperatūros svyravimai juose yra mažesni negu durpiniuose ir polipropileniniuose indeliuose. Krakmolo-rapsų išspaudų indeliai dirvožemyje suyra per 14 parų.The object of the study – biodegradable composites from starch, technical glycerol and rape seed cake. The aim of the study – preparation of composites useful for the fabrication of disposable pots for the cultivation of plants from the byproducts of biodiesel production, technical glycerol and rape seed cake. The methods of the study – universal test machine ZWICK/ROELL BDO-FBO.5TH was used for the investigation of the mechanical properties of the films of biocomposites. The standard methods were used for the estimation of the sorption properties, solubility in water, vapour permeability, humidity of soil, pH. Biodegradability of the films was estimated from the vegetation of fungus (Paecilomyces variotii, Penicillium sp., or Trichoderma virens) using the scale of five points. The results of the study. Polymer composites with the potential application in agriculure were prepared from starch, rape seed cake and pure glycerol. The investigation of mechanical properties of the composite films revealed decrease of tensile strength and increase of elasticity with the increase of the content of rape seed cake in the films. The highest elongation at break was observed for the films in which the ratios of starch and rape seed cake were 6:4 and 5:5. The solubility in water of the films increase with the increase of the content of rape seed cake. At the mass ratio of starch and rape seed cake of 4:6, the solubility of the films in water reaches 38.8 %. The amount of rape seed cake in the films has no substantial effect on their hygroscopicity. The saturation of the films with water vapour reaches 45 % at the ambient humidity of 100 %. The technical glycerol can be used for the plastification of the composite films of starch and rape seed cake only in combination with urea. The optimum mass ratio of technical glycerol and urea is in the range of 3:0.2-3:0.6. The composite films with the mass ratio of starch, rape seed cake, technical glycerol and urea 4:6:3:0.4 are the most suitable for the fabrication of the disposable pots. The films of such composition were used for the preparation of the experimental pots. The performance of the pots was studied in the vegetative tests. It was established that the performance and mechanical properties of the pots prepared from starch and rape seed cake based composites are better than those of the commercial peat pots. They are stronger, more elastic and less permeable to water vapour. At high ambient temperatures the fluctuations of soil temperature and moisture are lower than those observed in the peat and polypropylene pots. The pots prepared from starch and rape seed based composites degrade in soil within 14 days.Žemės ūkio akademijaVytauto Didžiojo universiteta

Biodegradable Polymer Composites from Organic and Inorganic Industrial Residues for Agricultural Applications

Disertacijoje išanalizuotos gamybos liekanų (galvijų ragų drožlių, fosfogipso, pušies žievės ir spyglių, rapsų išspaudų ir žalio glicerolio) panaudojimo galimybės žemės ūkio paskirties polimerinių biokompozitų gavimui. Nustatyta, kad dėl daugumos šių liekanų sudėtyje esančio azoto, fosforo junginių, jos gali atlikti ne tik polimerų užpildų, kuriais biokompozituose pakeičiama dalis polimero, funkciją, taip mažinant sunaudojamo polimero kiekį, bet ir suteikti gaminiams papildomų naudingų savybių. Panaudojant kaip rišiklį bioskaidų polimerą poli(vinilo alkoholį) ir gamybos metu susidarančias liekanas sukurti biokompozitai. Iš jų išlietos plėvelės ir ištirtos jų mechaninės, viskoelastinės, sorbcinės savybės. Biokompozitai su rapsų išspaudų, ragų miltų, fosfogipso ar jų mišinių užpildais panaudoti mineralinių trąšų granulėms padengti. Ištirtos jais dengtų trąšų granulių savybės, atlikti vegetaciniai bandymai tręšiant jomis pomidorų daigus. Biokompozitai su ragų miltų užpildu panaudoti mulčiavimo plėvelėms ant substrato paviršiaus sudaryti. Nustatyta, kad šios dangos sulėtina vandens išgaravimo greitį iš substrato 26–33 %, sumažina piktžolių daigumą bei padidina mikrobiologinį dirvožemio aktyvumą. Iš biokompozitų, kuriuose kaip užpildas panaudoti pušies žievės miltai, pagaminti indeliai, skirti augalams auginti. Ištirtos šių indelių eksploatacinės savybės bei atlikti vegetaciniai bandymai auginant juose serenčius. Nustatyta, kad vandens išgaravimo greitis per biokompozito indelių sieneles 45 % mažesnis, substrato temperatūra juose 3–4 C aukštesnė, lyginant su durpiniais indeliais. Augalai, auginti biokompozito indeliuose, turi geriau išvystytą šaknų sistemą nei auginti durpiniuose indeliuose.In this work the applicability of production residues, i.e. cattle horn shavings, phosphogypsum, pine bark and needles, rapeseed cake and crude glycerol for the preparation of polymer biocomposites for the agricultural applications were estimated. It was established that many residual products contain derivatives of nitrogen, phosphorus and other substances which can be serve as nutrients for plants. For this reason, they can serve not only as fillers of biocomposites, which enable to decrease the amount polymer required, but also as components providing other useful properties to the products. Biocomposites are developed using biodegradable polymer poly(vinyl alcohol) as a binder and meals of different residual products as the fillers. The films of the biocomposites were casted and their mechanical, viscoelastic and sorption properties were studied. Biocomposites containing meals of rape seed cake, horn meal, phosphogypsum or their mixtures as the fillers were used for coating of granules of mineral fertilizers. The properties of the fertilizers granules of which were coated with the biocomposite films were studied and tested in the cultivation of tomato sprouts. Biocomposites containing horn meal as the filler were used for the formation of mulch films on the surface of growing substrate. It was established that the mulch coatings prepared from the developed biocomposites decrease the rate of evaporation of water from the substrate by 26–33% and the viability of weeds and increase microbiological activity of soil. The films of the biocomposites filled with the pine bark meal were used for the fabrication of pots intended for cultivation of plants. Properties of the pots were studied and they were tested in the cultivation of Tagetes patula L. It was established that the rate of evaporation of water through the walls of the biocomposite pots was by 45% lower and the temperature of substrate in the biocomposite pots was by 3–4 C higher as compared with the corresponding characteristics of peat pots. Plants cultivated in the biocomposite pots had better developed root systems as compared to those cultivated in peat pots.Žemės ūkio akademijaVytauto Didžiojo universiteta

Polymer Composites for Mulching Coatings

The film-forming composites from poly(vinylalcohol), cattle horn mealand glycerolare proposed in this presentation for the formation of coatings for mulching of plants cultivated in pots and containers.Poly(vinyl alcohol)was used as a binder. Horn meal was used as the nitrogen containing filler. Glycerol was used as a plasticizer.The effect of the particle size of horn meal on the mechanical properties, water vapour permeability, solubility of the films cast from the composites was studied. The decrease of the particle size of the filler leads to the increase of tensile strength and of elongation at break and to the decrease of water vapour permeability of the films. In addition, the decrease of the particle size of the filler leads to the increase of the amount of water soluble nitrogen in films. The composites were used for the mulching of the tomato sprouts cultivated in pots. For the preparation of mulching coatings the liquid mulching composition was spread out on the surface of the growing media. After evaporation of water the polymer coatings, acting as the mulch films, were obtained. The effect of the particle size of horn meal in the mulching composition on the quality of mulch coatings, the rate of evaporation of water from the growing substrate and on plant growth was studied.It was established that the proposed mulch films retain moisture in the pots and stimulate growth of sproutsVytauto Didžiojo universitetasŽemės ūkio akademij

Effect of crude glycerol on the properties horn meal filled poly(vinyl alcohol) composites as materials for mulching coatings

Vytauto Didžiojo universitetasŽemės ūkio akademij

Film-Forming Starch Composites for Agricultural Applications

Biodegradable polymer composites were prepared from starch, crude glycerol, rapeseed cake and urea. The uniform films of the composites were prepared by casting technique. Mechanical properties and solubility in water of the films were studied. Increase of the content of rapeseed cake in the composites lead to the decrease of tensile strength and to the increase of elongation at break. The solubility of the composites in water increased with the increase of the content of rapeseed cake and urea. The changes of pH of soil being in the contact with the composite films were studied. It was established that the composites with the ratio of starch, rapeseed cake, crude glycerol and urea ranging from 4:6:3:0.2 to 4:6:3:1 can be used for the production of disposable plant pots. Too high content of urea can increase pH of soil up to the limit dangerous for plantsVytauto Didžiojo universitetasŽemės ūkio akademij

Biodegradable polymer composites and their aplication in agriculture

Vytauto Didžiojo universitetasŽemės ūkio akademij

Slow-release fertilizers based on biodegradable polymer composites

Vytauto Didžiojo universitetasŽemės ūkio akademij

Bioskaidžių plėvelių iš krakmolo ir biodegalų gamybos atliekų savybių tyrimai

Vytauto Didžiojo universitetasŽemės ūkio akademij

Biodegradble polymer composites containing nutrients for slow release fertilisers

Vytauto Didžiojo universitetasŽemės ūkio akademij

Biodegradable polymer composites with nitrogen- and phosphorus-containing waste materials as the fillers

Composites consisting of polyvinyl alcohol, nitrogen- and phosphorus-containing waste materials were prepared and studied as materials for encapsulation of mineral fertilizers By-products of biodiesel production (rapeseed cake, crude glycerol), horn meal (waste product of haberdashery) and phosphogypsum (by-product of the production of phosphorus fertilizers) were used as the fillers of the composites. The films of the composites with the different amounts of nitrogen and phosphorus were prepared using different fillers or their mixtures. Mechanical, properties of the films, hygroscopicity, solubility in water were studied. The composites developed were used for the encapsulation of mineral fertilizers. It was established that encapsulation resulted in the increase of the time of release of the fertilizers. The developed slow-release fertilizers represent a combination of inorganic and organic compounds. The organic part consists of nitrogen- and phosphorus containing horn meal and rapeseed cake. Since assimilation of organic substances is considerably longer, nitrogen and phosphorus of these components will be available for plants much later than inorganic nitrogen and phosphorus. Thus the composite film will not only decrease the rate of desorption of the components from the granules of the fertilizers but will also prolong the impact of the fertilizers on the plantsVytauto Didžiojo universitetasŽemės ūkio akademij