Flax fibers as natural filler for rigid polyurethane- -polyisocyanurate foams based on bio-polyol from rapeseed oil

The influence of flax fibers on the physical and mechanical properties and the flammability of rigid polyurethane-polyisocyanurate foams obtained from rapeseed oil-based polyol was analyzed. The rigid polyurethane-polyisocyanurate foams with apparent density of 40−48 kg/m3 were prepared. It has been found that the introduction of flax fiber has a beneficial effect on selected properties of obtained foams

Modification of expandable polystyrene beads

This paper presents the effect of modification of expandable polystyrene beads (PSB) with an additional amount of physical blowing agent and the addition of ethylene wax on their properties. Three different sizes of PSB beads were analyzed. The bulk density and thermal properties – thermogravimetric and differential scanning calorimetry were evaluated

Tailoring Mechanical Properties of Rigid Polyurethane Foams by Sorbitol and Corn Derived Biopolyol Mixtures

Sorbitol arises to be a strong candidate for renewably sourced polyol synthesis. Moreover, processes for extracting sorbitol directly from cellulosic materials are effective, and materials such as agroforestry residues could be used as green sorbitol sources. Rigid polyurethane foams were successfully synthesized by using mixtures of a sorbitol based high functionality polyol and a corn based diol. Microstructure and properties of the rigid polyurethane foams were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, thermal conductivity measurements, compression tests, and dynamic mechanical analysis. Results showed that the cross-linking density of the formed polymer network was directly modified by polyol mixture ratio, and microstructure and properties also changed in consonance. The incorporation of different amounts of a diol with longer chain length between hydroxyl groups allowed fixing the rigidity of the foams, opening the door to the possibility of designing rigid polyurethane foams with tailored properties.Financial support from the Basque Government in the frame of Grupos Consolidados (IT-776-13) and from European Union-FP7-PIRSES-GA-2012-BIOPURFIL program is gratefully acknowledged. Additionally, the author thanks the University of the Basque Country (UPV/EHU) for funding this work (PIFUPV047/2011). Technical support provided by SGIker (UPV/EHU, MINECO, GV/EJ, ESF) is gratefully acknowledged

Synthesis of thermal insulating polyurethane foams from lignin and rapeseed based polyols: a comparative study

Nowadays, a large number of polyurethane (PU) system modifications relies on the use of different bio-polyols. In this context, two bio-based polyols, one synthesized from lignin and one from rapeseed oil were evaluated in the replacement of a petrochemical polyol at an amount of 10–30 wt.% in rigid polyurethane foam formulations (RPU). The lignin-based polyol was produced by oxypropylation from an organosolv lignin (ALCELL) and the rapeseed oil-based one prepared by a two-step method of epoxidation followed by oxirane ring opening with diethylene glycol. The replacement of the petrochemical polyol with the lignin bio-polyol increased the reactivity of the reactive mixtures, while the rapeseed oil bio-polyol gave the opposite effect. This was confirmed by the respective changes observed in the dielectric polarization of the reactive mixtures together with the maximum temperature achieved in the foam core during the foaming process. The foams modified with the tested bio-polyols had both lower apparent density (40–45 kg/m3) and closed cell content (86–89%), comparatively with a reference foam. The replacement of petrochemical polyol with the bio-polyols up to 30 wt% caused, in the modified foams, a slight decrease of the compressive strength. Moreover, the introduction of the bio-polyols into PU formulations generally did not influence the thermal conductivity coefficient that was around 23 mW/m·K for the obtained materials.info:eu-repo/semantics/publishedVersio

Rigid polyurethane foams modified with liginin based bio-polyols

Nowadays, a large number of polyurethane (PU) systems modifications relies on the use of different bio-polyols, as described in literature. Among them, one of the most important is the incorporation of bio-polyols based on plant wastes such as lignin. In this work, two bio-polyols have been synthesized from a technical lignin and applied to obtain rigid PU foams (10-30wt. in polyol premix). The lignin, obtained by an organosolv process (aqueous ethanol) proceeds from hardwoods and was converted into liquid bio-polyols by an oxypropylation process. The addition of the lignin-based bio-polyols to the PU system increased its reactivity, as confirmed by a faster decrease of the dielectric polarization and an increase of the maximum temperature in the foam core during the foaming process. The foam modified with these bio-polyols had a slightly lower apparent density and compressive strength. The obtained foams have an apparent density and a closed cell content of about 40 to 45 kg/m3 and 86-89%, respectively. The compressive strength of the foams decrease as the bio-polyol content increased. On the other hand the thermal conductivities of the obtained materials were similar ca. 23 mW/m·K. Concerning thermal stability, lignin-based foams start to degrade at lower temperatures and show a slower degradation pattern (high residue in TG).info:eu-repo/semantics/publishedVersio

Факторы риска развития синдрома вегетативных дисфункций и признаков дисплазии соединительной ткани

СОЕДИНИТЕЛЬНОЙ ТКАНИ БОЛЕЗНИФАКТОРЫ РИСКАНЕРВНОЙ СИСТЕМЫ ВЕГЕТАТИВНОЙ ДИСФУНКЦИЯ НАСЛЕДСТВЕННАЯНЕРВНОЙ СИСТЕМЫ ВЕГЕТАТИВНОЙ БОЛЕЗНИДЕТЕЙ ОХРАНЫ ЗДОРОВЬЯ СЛУЖБ

Introduction to bio-based materials and biotechnologies for eco-efficient construction

This chapter introduces some sustainability challenges, as well as the importance of resource efficiency and the European bioeconomy strategy. The importance of biobased materials and biotech admixtures for eco-efficient construction is summarized. The importance of changing the curriculum of civil engineering to address sustainability challenges and also enhance the collaboration between civil engineers and biotech experts is briefly discussed. Comments concerning the biobased and biotech related publication intensity of several well know civil engineering departments are also made. An outline of the book is also given