Mikelis Kirpluks

Three Different Approaches for Polyol Synthesis from Rapeseed Oil

Three different kinds of polyols from rapeseed oil were synthesised and characterized during this study. Afterwards, using these polyols rigid polyurethane foams were produced, which are used as thermal insulation material in construction industry and in production of refrigerators. Polyols from rapeseed oil were synthesised by epoxidation, transamidization and transesterification methods. One rapeseed oil based polyol was synthesized by partial epoxidation of the double bonds in fatty acid chains and overall opening oxirane rings by using diethylene glycol. Other two methods transamidization and transesterification of ester bonds of triglyceride were carried out using diethanolamine and triethanolamine respectively. To use these polyols for production of polyurethane foams, hydroxyl value, acid value, water content, viscosity and density of polyols were determinated. The functionality of obtained polyols was calculated on the base of number-average molecular weight and hydroxyl value. After laboratory trials a pilot scale production of the rapeseed oil polyols was carried out in 50 L reactor. From synthesized polyols rigid polyurethane foam samples were produced in laboratory scale and also in semi industrial scale, using industrial high pressure spraying equipment machine. Technological parameters, density and closed cell content were determined for obtained polyurethane foams.

Rigid Polyurethane Foam Thermal Insulation Protected with Mineral Intumescent Mat

Abstract One of the biggest disadvantages of rigid polyurethane (PU) foams is its low thermal resistance, high flammability and high smoke production. Greatest advantage of this thermal insulation material is its low thermal conductivity (λ), which at 18-28 mW/(m•K) is superior to other materials. To lower the flammability of PU foams, different flame retardants (FR) are used. Usually, industrially viable are halogenated liquid FRs but recent trends in EU regulations show that they are not desirable any more. Main concern is toxicity of smoke and health hazard form volatiles in PU foam materials. Development of intumescent passive fire protection for foam materials would answer problems with flammability without using halogenated FRs. It is possible to add expandable graphite (EG) into PU foam structure but this increases the thermal conductivity greatly. Thus, the main advantage of PU foam is lost. To decrease the flammability of PU foams, three different contents 3%; 9% and 15% of EG were added to PU foam formulation. Sample with 15% of EG increased λ of PU foam from 24.0 to 30.0 mW/(m•K). This paper describes the study where PU foam developed from renewable resources is protected with thermally expandable intumescent mat from Technical Fibre Products Ltd. (TFP) as an alternative to EG added into PU material. TFP produces range of mineral fibre mats with EG that produce passive fire barrier. Two type mats were used to develop sandwich-type PU foams. Also, synergy effect of non-halogenated FR, dimethyl propyl phosphate and EG was studied. Flammability of developed materials was assessed using Cone Calorimeter equipment. Density, thermal conductivity, compression strength and modulus of elasticity were tested for developed PU foams. PU foam morphology was assessed from scanning electron microscopy images.

Rigid polyurethane foams obtained from tall oil and filled with natural fibers: Application as a support for immobilization of lignin-degrading microorganisms

The forest biomass represents an abundant, renewable, non-food competition, and low-cost resource that can play an alternative role to petro-resources. The first topic of the research activity is focused on the use of wood and a pulp mill by-product—tall oil —as raw materials for the production of rigid polyurethane foams. The maximum content of the renewable resource in ready foams is 26%. By using biopolymers as a matrix, a natural way is to reinforce them with natural fibers. Further advantages are significant weight and cost savings and, at the same time, replacement of petrochemical raw materials. Three different natural fibers (cellulose, wood, and modified cellulose) were tested as a filler of foams. Rigid polyurethane foams was used as biomass support particles for immobilization of microorganisms. Suspension cultures of the organism with biomass support particles can promote the adhesion of cells to the porous matrix surface, and subsequently the cells become immobilized during the cultivation. This method for cell immobilization has a great potential for enhancing the production of proteins or chemicals in culture supernatants. The presence of natural fibers in the matrix promotes the enzyme production because the material not only functions as an attachment place but also supplies some nutrients to the microorganism and induces the production of ligninolytic enzymes. This paper discusses the studies into the use of tall oil as a renewable source in rigid polyurethane foam production

Structure, Mechanical, Thermal and Fire Behavior Assessments of Environmentally Friendly Crude Glycerol-Based Rigid Polyisocyanurate Foams

In this work, rigid polyisocyanurate foams were prepared at partial substitution (0–70 wt%) of commercially available petrochemical polyol, with previously synthesized biopolyol based on crude glycerol and castor oil. Influence of the biopolyol content on morphology, chemical structure, static and dynamic mechanical properties, thermal insulation properties, thermal stability and flammability was investigated. Incorporation of 35 wt% of crude glycerol-based polyol had reduced average cell size by more than 30% and slightly increased closed cell content, simultaneously reducing thermal conductivity coefficient of foam by 12% and inhibiting their thermal aging. Applied modifications showed also positive impact on the mechanical performance of rigid foams. Increase of crosslink density resulted in enhancement of compressive strength by more than 100%. Incorporation of prepared biopolyol resulted in enhancement of thermal stability and changes in degradation pathway. Up to 35 wt% share of crude glycerol-based polyol, foams showed similar flammability as reference sample, which can be considered very beneficial from the environmental point of view.

The Effect of Montmorillonite Type Nanoparticles on Stiffness and Flammability of Rapeseed Oil Based Polyisocyanurate Foams

Polyisocyanurate foams incorporating polyols derived from rapeseed oil are developed, with the polyol system comprising up to 80% of rapeseed oil esters. To enhance the mechanical characteristics and fire resistance of the foams, they are filled with three different types of organically modified clay (organoclay) in the range of loading from 1 to 5% by weight. Marked increase in tensile stiffness of nanocomposite foams is observed.

Rapeseed Oil as Feedstock for High Functionality Polyol Synthesis

In this study, polyols with high average functionality were synthesized from a renewable resource, rapeseed oil, as raw material for rigid PU foam production. A well-known method of rapeseed oil fatty acid double bond epoxidation was used to introduce oxirane rings into rapeseed oil structure. The temperature infl uence on epoxidation reaction conversion rate was studied by volumetric and FTIR spectra analysis. After epoxidation of rapeseed oil, an oxirane ring-opening reaction was carried out to obtain high functionality polyols. Diethylene glycol, a conventional oxirane ring-opening reagent, was compared to amine-based polyfunctional alcohols, diethanolamine and triethanolamine. The introduction of tertiary amine groups into the polyol structure provided catalytical properties for obtained polyols, which will allow a reduction of the amount of catalysts in polyurethane foam formulations. Hydroxyl value, acid value, moisture content, viscosity and density of synthesized polyols were determined, and their structure and average functionality were analyzed by FTIR and MALDI-TOF spectroscopy and GPC analysis. Also, the main characteristics of rigid PU foam obtained from synthesized polyols were determined.

Crude Tall Oil as Raw Material for Rigid Polyurethane Foams with Low Water Absorption

The synthesis technology of polyol from crude deciduous tree tall oil was developed, the structure of obtained polyol was analyzed using FTIR spectroscopy. Compositions of rigid polyurethane (PUR) foams were formulated using polyol from crude deciduous tree tall oil, Isocyanate indexes varied in wide range from 150 to 300. The densities of obtained rigid polyurethane foams was in range from 44-101 kg/m3. Produced rigid PUR foams were characterized by good compression characteristics and low water absorption. The optimal water absorption was achieved at density lower than 50 kg/m3 and Isocyanate index lower than 175. Thus the obtained PUR foams have the potential to be used for boat construction or for production of life-saving equipment.

Evaluation of the Apparent Interfacial Shear Strength of Nanocellulose/PVA Composites

Nanocellulose in the form of whiskers and nanofibers has become a promising reinforcement material for polymer composites due to its high mechanical characteristics and sustainability. For optimization of composite properties, efficient means of characterization of the stress transfer between fibrous nanofiller and the polymer matrix are needed. In the current work, the apparent interfacial shear strength (IFSS) of cellulose nanofiber/PVA is evaluated by a modified Bowyer and Bader method based on an analysis of the stress–strain curve of a composite film in uniaxial tension. The IFSS is found to exceed shear yield strength of the neat polymer, suggesting good adhesion.