Research of Biopolyurethane Foam Modified With Paper Production Waste

Disertacijoje nagrinėjamos modifikuotos standžiosios poliuretano putos iš biopoliolių, kurių struktūros ir savybių keitimui naudojamos termiškai ir chemiškai apdorotos popieriaus gamybos atliekų dumblo dalelės. Detaliai išanalizavus šios atliekos savybes bei poveikį gaminiams, galima sukurti putas, pasižyminčias norminiais dokumentais apibrėžtomis bei termoizoliacinėms medžiagoms būdingomis savybėmis. Disertacijos tikslas – sukurti ir ištirti poliuretano putas, susintetintas iš rapsų aliejaus poliolių ir modifikuotas popieriaus gamybos atliekų dumblo dalelėmis. Disertaciją sudaro įvadas, trys skyriai, bendrosios išvados, literatūros ir autorės publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formu-luojamas darbo tikslas bei uždaviniai šiam tikslui pasiekti, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė bei ginamieji teiginiai. Įvado pabaigoje pristatomos disertacijos tema autorės paskelbtos publikacijos ir pranešimai konferencijose bei disertacijos struktūra. Pirmajame skyriuje aptartas atsinaujinančių išteklių, kaip dar vienos priemonės, darniojo vystymosi tikslų įgyvendinimui naudojimas poliuretano putų gamyboje. Taip pat nagrinėjama pagrindinių poliuretano putų žaliavų – poliolių, izocianato, vandens, katalizatorių, paviršių aktyvinančių medžiagų poveikis galutinių gaminių struktūrai ir savybėms. Apžvelgiamos galimybės poliuretano putų savybių modifikavimui naudoti daugiafunkcius grandinės plėtiklius. Taip pat analizuojamas popieriaus gamybos atliekų dumblas, susidarantis atliekinio vandens valymo įrenginiuose, bei jo panaudojimo galimybės statybinių medžiagų pramonėje, kitų užpildų poveikis polimerinių medžiagų savybėms, titanatų, silanų bei cirkonatų panaudojimas. Antrajame skyriuje aprašomos darbe naudotos žaliavos ir jų savybės, taikyti tyrimų metodai bei poliuretano putų, propilenglikoliu ir popieriaus gamybos atliekų dumblo dalelėmis modifikuotų poliuretano putų sudėtys bei technologinė bandinių gamybos schema. Trečiajame skyriuje tiriamas vandens kiekio poveikis poliuretano putų tankiui, pradinei susitraukčiai bei matmenų stabilumui padidintos temperatūros ir drėgmės sąlygomis. Papildomai tiriamas propilenglikolio iš rapsų glicerino ir rapsų glicerino, kaip grandinės plėtiklio, poveikis gaminių fizikinėms ir mechaninėms savybėms. Taip pat pateikiami propilenglikoliu ir popieriaus gamybos atliekų dumblo dalelėmis modifikuotų poliolio mišinių klampos bei poliuretano putų eksploatacinių savybių ir struktūros tyrimų rezultatai. Disertacijos medžiaga paskelbta 5 moksliniuose straipsniuose, o tyrimų rezultatai pristatyti 6 nacionalinėse ir tarptautinėse mokslinėse konferencijose

Dimensionally stable water-blown polyurethane foam extended with bio-based propylene glycol and modified with paper waste sludge

Paper waste sludge (PWS) is the main and the greatest by-product in paper production process, and its elimination as well as destruction is a primary environmental problem. This research explores the feasibility of such wastes to be used in polyurethane foam composites. It is well known that using water as a sole blowing agent has major drawbacks such as long demould time, shrinkage, high diffusion rate of carbon dioxide and etc.; therefore, the bio-based propylene glycol (RPG) is used in order to solve such problems. The addition of 20 parts by weight (pbw) of RPG eliminates the primary shrinkage of the foam composites when PWS is used in the amount varying from 5% to 20%, and improves the dimensional stability at 70 oC and 90% relative humidity conditions. The addition of titanate coupling agent modified PWS particles increases the compressive strength of the final composites from  ̴ 26% to  ̴ 53%, from  ̴ 17% to  ̴ 31% and from  ̴ 3% to  ̴ 23% for, respectively, 10 pbw, 15 pbw and 20 pbw RPG extended foam composites

The impact of chain extender on the properties of polyurethane foam based on rapeseed oil polyol obtained via chemo–enzymatic route

Presently, researches regarding green chemistry are conducted due to its significance for the mitigation of environmental problems, particularly those related to carbon dioxide emissions in relation to global warming and the usage of fossil feedstocks not only for energy generation but also for materials production. The study examines the impact of bio-products such as corn starch, rapeseed glycerin as well as petroleum based propylene glycol as bifunctional and trifunctional chain extenders on physical-mechanical properties of polyurethane foam from rapeseed oil polyol derived via chemo-enzymatic route. The obtained foams were characterized using European and international methodologies for determination of density, compressive strength perpendicular and parallel to foaming directions, thermal conductivity, long-term water absorption after 28 days of immersion, closed cell content and cell size. Foams containing (5–25) pphp of corn starch display significantly lower values in density and compressive strength as well as cell size compared to the neat polyurethane foam. The greatest compressive strength and the lowest thermal conductivity are obtained for foams with 25 pphp of rapeseed glycerin. All foams extended with bio-products and propylene glycol are characterized by the higher long-term water absorption compared to that of the neat polyurethane foam

Imidazolium ionic liquids as compatibilizer agents for microcrystalline cellulose/epoxy composites

Four imidazolium-based ionic liquids (IL; 1-butyl-3-methylimidazolium chloride, 1-carboxymethyl3-methylimidazolium chloride, 1,3-dicarboxymethylimidazolium chloride and 1-(2-hydroxyethyl)- 3-methylimidazolium chloride) were tested as compatibilizers of microcrystalline cellulose (MCC). Subsequently, ethanolic IL solutions were prepared; MCC was mixed, and the mixtures were left to evaporate the ethanol at ambient conditions. These modified MCC were characterized and applied as reinforcements (5.0 and 10 phr) in an epoxy resin aiming to manufacture biobased composites with enhanced performances. The IL did not significantly modify the morphological and structural characteristics of such reinforcements. Regarding the thermal stability, the slight increase was associated with the MCC-IL affinity. The IL-modified MCC-epoxy composites presented improved mechanical responses, such as flexural strength (≈22.5%) and toughness behavior (≈18.6%), compared with pure epoxy. Such improvement was also obtained for the viscoelastic response, where the storage modulus at the glassy state depended on the MCC amount and IL type. These differences were associated with stronger hydrogen bonding between IL and epoxy hardener or the IL with MCC, causing a “bridging” effect between MCC and epoxy matrix

Rigid polyurethane biofoams filled with pine seed shell and yerba mate wastes

Pine seed shells and yerba mate are common wastes leftover from the food and beverage industry. This study presents the development of rigid polyurethane foams (RPUFs) filled with pine seed shells and yerba mate at 5, 10 and 15 wt%. The fillers were characterized for chemical properties using bench chemistry analyses, and the RPUFs were investigated in terms of chemical, morphological, mechanical, thermal and colorimetric characteristics. The main results indicated that yerba mate showed good compatibility with the polyurethane system, probably because its available hydroxyl groups reacted with isocyanate groups to form urethane bonds, producing increases in mechanical and thermal properties. However, pine seed shell did not appear to be compatible. Anisotropy increased slightly, as there was an increase in the percentage of reinforcement. The mechanical properties of the yerba mate reinforced foams proved stable, while there was a loss of overall up to ~50% for all mechanical properties in those reinforced with pine seed shell. Thermal properties were improved up to ~40% for the yerba mate reinforced foams, while those reinforced with pine nuts were stable. It was possible to observe a decrease in the glass transition temperature (Tg) of ~−5 °C for the yerba mate reinforced foams and ~−14 °C for the pine seed shell reinforced ones

Optimization of pin position and angle for Z-pin-reinforced foam core sandwich structures

Sandwich panels (SP) are very promising components for structures as they ally high levels of specific stiffness and strength. Civil, marine and automotive industries are some examples of the sectors that use SPs frequently. This work demonstrates the potential of manufacturing Z-pin-reinforced foam core SPs, using a design strategy that indicated optimal values for both pin position and angle, keeping the same pin diameter as determined in a previous study. A simple search algorithm was applied to optimize each design, ensuring maximum flexural stiffness. Designs using optimal pin position, optimal pin angle and optimal values for both parameters are herein investigated using numerical and experimental approaches. The optimal pin position yielded an increase in flexural stiffness of around 8.0% when compared to the non-optimized design. In this same comparison, the optimal pin angle by itself increased the flexural stiffness by about 63.0%. Besides, the highest increase in the maximum load was found for those composites, molded with optimized levels of pin position and pin angle, which synergistically contributed to this result. All results were demonstrated with numerical and experimental results and there was a good agreement between them

Wood-poly(furfuryl alcohol) prepreg : a novel, ecofriendly laminate composite

Prepregs are commonly fabricated with non-renewable petroleum-based materials. To reduce the impact of the manufacturing of these materials and to produce more sustainable prepregs, this research aims to manufacture poly(furfuryl alcohol)/wood veneer prepregs and their posterior molding in laminate composites. For this purpose, the vacuum infusion process was used to impregnate the wood veneers, and compression molding was applied to manufacture three- and four-layer laminate composites. Scanning electronic microscopy was used to evaluate the impregnation. the laminate manufacturing and differential scanning calorimetry were used to predict the shelf-life of the prepregs, Fourier-transform infrared was used to evaluate the induced hydrolysis resistance, and thermogravimetric analysis was used to determine the thermal degradation of the laminates. Moreover, water uptake and flexural, compressive, and tensile properties were evaluated. The kinetic models were effective and showed a shelf life for the laminates of approximately 30 days in storage at −7 °C, which is an interesting result for laminates with lignocellulosic materials. FTIR proved the laminates’ excellent resistance to hydrolysis. The water absorption, thermal stability, and mechanical properties did not differ as the amount of wood veneer increased, but these results were up to ~40% higher compared with unidirectional wood laminates found in the literature, which is probably linked to the excellent interface observed with SEM

Evaluation of forming mixture composition impact on properties of water blown rigid polyurethane (PUR) foam from rapeseed oil polyol

Rapeseed oil based water blown rigid polyurethane foam was prepared by two shot method. Water was used as a blowing agent on purpose to increase the green nature of the foams. In order to reduce the temperature and shrinkage, acetone and glycerine were added. The influence of these additives on foaming characteristics, density, closed cell content, compressive strength and water absorption was described. It was found that reduction in shrinkage using glycerine leads to greater open cell content and water absorption, lower compressive strength (by almost 72% and 53%), density (by almost 64% and 74%) for moulded and free rise specimens, respectively, and delayed cream time of foaming mixture. The use of acetone reduced foam formation temperature by 15 ◦C, increased moulded and free rise densities by approximately 8%, as well as compressive strength by 22%, and by 10% for moulded and free rise water blown polyurethane specimens.This work has been supported by the Research Council of Lithuania (Project, No. ATE-07/2012)

Application of Walnut Shells-Derived Biopolyol in the Synthesis of Rigid Polyurethane Foams

This study aimed to examine rigid polyurethane (PUR) foam properties that were synthesized from walnut shells (WS)-based polyol. The Fourier Transform Infrared Spectroscopy (FTIR) results revealed that the liquefaction of walnut shells was successfully performed. The three types of polyurethane (PUR) foams were synthesized by replacement of 10, 20, and 30 wt% of a petrochemical polyol with WS-based polyol. The impact of WS-based polyol on the cellular morphology, mechanical, thermal, and insulating characteristics of PUR foams was examined. The produced PUR foams had apparent densities from 37 to 39 kg m−3, depending on the weight ratio of WS-based polyol. PUR foams that were obtained from WS-based polyol exhibited improved mechanical characteristics when compared with PUR foams that were derived from the petrochemical polyol. PUR foams produced from WS-based polyol showed compressive strength from 255 to 310 kPa, flexural strength from 420 to 458 kPa, and impact strength from 340 to 368 kPa. The foams that were produced from WS-based polyol exhibited less uniform cell structure than foams derived from the petrochemical polyol. The thermal conductivity of the PUR foams ranged between 0.026 and 0.032 W m−1K−1, depending on the concentration of WS-based polyol. The addition of WS-based polyol had no significant influence on the thermal degradation characteristics of PUR foams. The maximum temperature of thermal decomposition was observed for PUR foams with the highest loading of WS-based polyol.This article belongs to the Special Issue Performance Research of Polyurethane Foams and Composite

The Impact of Hemp Shives Impregnated with Selected Plant Oils on Mechanical, Thermal, and Insulating Properties of Polyurethane Composite Foams

Polyurethane (PUR) foams reinforced with 2 wt.% hemp shives (HS) fillers were successfully synthesized. Three different types of HS fillers were evaluated—non-treated HS, HS impregnated with sunflower oil (SO) and HS impregnated with tung oil (TO). The impact of each type of HS fillers on cellular morphology, mechanical performances, thermal stability, and flame retardancy was evaluated. It has been shown that the addition of HS fillers improved the mechanical characteristics of PUR foams. Among all modified series, the greatest improvement was observed after the incorporation of non-treated HS filler—when compared with neat foams, the value of compressive strength increased by ~13%. Moreover, the incorporation of impregnated HS fillers resulted in the improvement of thermal stability and flame retardancy of PUR foams. For example, the addition of both types of impregnated HS fillers significantly decreased the value of heat peak release (pHRR), total smoke release (TSR), and limiting oxygen index (LOI). Moreover, the PUR foams containing impregnated fillers were characterized by improved hydrophobicity and limited water uptake. The obtained results confirmed that the modification of PUR foams with non-treated and impregnated HS fillers may be a successful approach in producing polymeric composites with improved properties.This article belongs to the Special Issue Environmentally Friendly Polymeric Blends from Renewable Source