Effect of lignins on structure, tensile and thermal properties of polyurethanes films

The organosolv lignins of wheat straw acts as a cross linking macromonomer in PU compositions. The fractionation of lignin and variation of fractions contents in PU composition allow to control the properties of PU films and to obtain the elastomers in high elastic state at room temperature or rigid and glassy crosslinked PU

The wheat straw lignin as renewable polyol for polyurethanes elastomers

The novel wheat straw) produced on CIMV pilot plant (France) was sequential extracted with organic solvents of different polarity (dichloromethane, methanol and dichloromethane/methanol mixture. Parent lignin was characterized by a weak activity in reaction with MDI in comparison with fractionated lignins. In this study the effects of lignin on the properties of PU elastomers obtained from three components systems included polyethelene glykol (Mn=400 g/mol) as a soft segment, fractionated lignins and commercial polymeric diphenylmethane diisocyanate Voratec SD 100 were investigate

Polyoxometallate catalyzed oxidative modification of lignin as a favorable pre-treatment for copolymerization with propylene oxide for polyurethanes production

The oxypropylation of the parent and oxidized lignins with propylene oxide (PO) was studied in high pressure Parr reactor using KOH as a catalyst. It was shown that oxypropylation of lignin pre-oxidized in the system POM/H2O2 proceeded in the similar manner as the parent lignin but the rate of the process was some lower due to the presence of higher amount of -COOH groups with lower nucleophilicity

The effect of alkali catalyst content and water content in organosolve wheat straw lignin on process of it oxypropylation and characteristics of lignopolyols obtained

The novel wheat straw organosolv lignin (BIOLIGNIN) produced on CIMV pilot plant (France) was oxypropylated at propylene oxide lignin ratio equal 7/3 in laboratory scale high pressure Parr reactor using different KOH content and water content in lignin. It was shown that in dependence of reaction condition the yield of solid non-liquified fraction varied in the range 0.1-9.9%

Influence of Long-Term Storage and UV Light Exposure on Characteristics of Polyurethane Foams for Cryogenic Insulation

Rigid polyurethane (PUR) foams have been the most effective insulation material used in space launchers since the beginning of cryogenic fuel use, due to their outstanding thermal and mechanical properties. In this study, spray-applied PUR foams using different ratios of amine-based catalysts were produced. Due to climate change, several restrictions have been made regarding the usage of blowing agents used for PUR foam production. Lately, hydrofluoroolefins (HFOs) have been suggested as an alternative for PUR foam production due to their low global warming potential (GWP) and ozone depletion potential (ODP), replacing the hydrofluorocarbons (HFCs) so far used. This change in blowing agents naturally altered the usage of catalysts. Reactive amine-based catalysts are less hazardous because of their low volatility and ability to react successfully with isocyanate or polyols. Spray-applied PUR foams with a potential application for cryogenic insulation were produced and tested for long-term storage, analyzing parameters such as the pH value of polyol composition, foaming kinetics (trise, tcream), etc. Athermal analysis (TG, DSC) was also applied to developed materials, as well as artificial ageing by exposing samples to UV light. It was discovered that PUR foams obtained using reactive amine-based catalysts, such as Polycat 203 and 218, have a higher integral heat capacity, but polyol mixtures containing these catalysts cannot exceed a storage time of more than 4 months. It was also observed from artificial ageing tests of PUR cryogenic insulation by exposure to UV light that the thickness of the degraded layer reached 0.8 mm (after 1000 h), but no significant destruction of cellular structure deeper in the material was observed

A Review of Wood Biomass-Based Fatty Acids and Rosin Acids Use in Polymeric Materials

In recent decades, vegetable oils as a potential replacement for petrochemical materials have been extensively studied. Tall oil (crude tall oil, distilled tall oil, tall oil fatty acids, and rosin acids) is a good source to be turned into polymeric materials. Unlike vegetable oils, tall oil is considered as lignocellulosic plant biomass waste and is considered to be the second-generation raw material, thus it is not competing with the food and feed chain. The main purpose of this review article is to identify in what kind of polymeric materials wood biomass-based fatty acids and rosin acids have been applied and their impact on the properties

Two Approaches of Introduction of Wheat Straw Lignin in Rigid Polyurethane Foams

Different separate approaches of CIMV lignin introduction into PUR foam system were studied: as filler without chemical preprocessing and as liquid lignopolyol obtained by lignin oxypropylation in alkali conditions. The incorporation of increasing amount of lignin as filler into reference PUR foam systems on the basis of mixture of commercial polyethers Lupranol 3300 and Lupranol 3422 steadily decreased the compression characteristics of foams, their dimensional stability and hydrophobicity. The complete substitution of Lupranol 3300 by lignopolyol increases its cell structure uniformity and dimensional stability and does not reduce the physical-mechanical properties of foam

Natural Oil-Based Rigid Polyurethane Foam Thermal Insulation Applicable at Cryogenic Temperatures

This paper presents research into the preparation of rigid polyurethane foams with bio-polyols from rapeseed and tall oil. Rigid polyurethane foams were designed with a cryogenic insulation application for aerospace in mind. The polyurethane systems containing non-renewable diethylene glycol (DEG) were modified by replacing it with rapeseed oil-based low functional polyol (LF), obtained by a two-step reaction of epoxidation and oxirane ring opening with 1-hexanol. It was observed that as the proportion of the LF polyol in the polyurethane system increased, so too did the apparent density of the foam material. An increase in the value of the thermal conductivity coefficient was associated with an increase in the value of apparent density. Mechanical tests showed that the rigid polyurethane foam had higher compressive strength at cryogenic temperatures compared with the values obtained at room temperature. The adhesion test indicated that the foams subjected to cryo-shock obtained similar values of adhesion strength to the materials that were not subjected to this test. The results obtained were higher than 0.1 MPa, which is a favourable value for foam materials in low-temperature applications

Polyurethane Foam Composites Reinforced with Renewable Fillers for Cryogenic Insulation

Sawdust, microcellulose and nanocellulose and their silanized forms were used to reinforce rigid polyurethane (PU) foam composites. The concentration of fillers was varied in the range of 0.5–1.5%. For rigid PU foam formulations, three polyols from recycled and renewable materials were used, among other components. Polyols were obtained from rapeseed oil, tall oil fatty acids and recycled polyethylene terephthalate. As rigid PU foam composites in literature have been described as appropriate thermal insulation material, the appliance of obtained composites for cryogenic insulation was investigated by determining the various physical-mechanical properties of composites. The physical-mechanical properties, such as the modulus of elasticity, compressive and tensile strength in both 293 K and 77 K, adhesion measurements with and without cryo-shock, apparent density, thermal conductivity coefficient, and safety coefficient were measured. The results showed that the addition of fillers did not give a significant improvement of characteristics

Development of the approaches for complex utilization of brown algae (Fucus vesiculosus) biomass for the obtaining of value-added products

The seaweed collected after stranding on beaches of Latvia is underexploited natural resource, which has a potential as raw material for biologically active compound extraction for cosmetic and pharmacy and fertilizer in sustainable agriculture. The aim of the present study was development of the approach for the processing of brown alga Fucus vesiculosus biomass, collected from the Gulf of Riga. The thorough characterization of the chemical composition of Fucus vesiculosus has shown that it is a potential source for obtaining of nitrogen-containing fertilizers, and biologically active compounds. One of the proposed approaches for the processing of the Fucus vesiculosus biomass under study includes algae extraction with organic solvents and CaCl2 solution and obtaining soil organic amendment on the basis of the extract-free residue. The ethyl acetate extract was rich in phenolic compounds (430 ± 30 GAE mg/g) with high antioxidant activity in DPPH• and ABTS•+ tests. The ethanol extract contained significant amounts of phlorotannins that was confirmed by the data of LC-MS/MS analysis. The CaCl2 extract was used for the obtaining of sulphated polysaccharide fucoidane (yield ≈7% on the basis of oven dry matter, o.d.m.), which has numerous biological activities. The extract-free residue didn’t show phytotoxicity. The extract free algal biomass exhibited positive effect in root elongation tests with oat (Avena sativa). As alternative approach for processing of the algal biomass, the mechano-chemical treatment of algal biomass with lignin was proposed. EPR analyses confirmed interaction between algal biomass and lignin