Obtaining Polyurethane Microcapsules Using Interphases Polymerization

Microencapsulation is a process in which around solid particles, liquids or molecular dispersions spherical shell from other material is made. Capsule membrane can be one or multi-walled, with varied thickness, porosity, mechanical strength or size. Application areas of microcapsules include agriculture, pharmacy, food, cosmetics, textiles, paints, adhesives and coatings, etc [1]. In this work in order to obtain self-healing coating materials that can autonomously extend the lifetime of the surface material, polyurethane microcapsules were formed. Microcapsules were synthesized by interfacial polymerization. For capsule shell forming polyol (glycerol or 1,3-propanediol) and toluene diisocyanate was used, while role of active agent performed isophorone diisocyanate. As a solvent cyclohexanone was taken, but as surfactant – gum arabic. In order to evaluate morphology and surface features of microcapsules scanning electron microscope SEM Tescan TS 5136 MM with secondary electron detector and VEGA TC computer software was used. To ensure isocyanate existence inside capsules, samples were tested using FT-IR spectroscopy

High Functionality Polyols from Rapeseed Oil as Raw Material for Polyurethane Thermal Insulation

In this study IWC uses well known epoxy ring opening reaction [1] with different polyfunctional alcohols to obtain polyols with high reactivity and high functionality. Epoxidation of rapeseed oil was done by peroxyacetic acid, which was obtained from reaction between hydrogen peroxide and acetic acid, in presence of ion-exchange resin catalyst. Conversion of 84% of rapeseed oil double bonds was achieved and afterwards epoxy rings were opened with polyfunctional alcohols TEA and diethylene glycol (DEG). Molar ratio of epoxy groups and polyfunctional alcohol 1/1.1 was used. DEG polyol is already produced on industrial scale and it was chosen as comparison material. After epoxy ring opening additional amount of TEA was added to carry out transesterification of triglyceride ester bonds in presence of zinc acetate catalyst. Three different molar ratios of fatty acid triglyceride and TEA were studied: 1/1.5; 1/2.0 and 1/2.5. Following characteristics were determine for obtained polyols: hydroxyl value, acid value, viscosity, density and moisture. The structure of polyols were investigated by Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC). From GPC data average molecular weight (Mn), the weight average molecular weight (Mw), polydispersity index and average functionality of polyols was determine. Obtained polyols were used to produce rigid PU foam thermal insulation materials for which thermal conductivity, apparent density and compression strength was tested. This study showed that it is possible to obtain good quality polyols and rigid PU foams that are comparable to petrochemical materials and conventional bio-based polyols. Obtained TEA polyols had much higher reactivity than DEG polyol. Also their OH value was higher 550±15 to 242±15 mgKOH/g. From FTIR spectra it was seen that full epoxy group conversion was achieved, but GPC data showed that oligomers with high Mn were obtained, especially in case of DEG polyol which’s Mn was 2542 g/mol compared to TEA polyol with Mn of 709 g/mol

Microwave Synthesis of Polyols for Urethane Materials

All type of thermally driven chemical reactions can be accelerated by microwaves (MW). From the early 1980-ties, many investigations have been performed in the field of MW synthesis of different organic substances. It is possible significantly to decrease the synthesis reaction time from hours to minutes. Arrhenius equation (Eq.1) testifies that very low activation energy should be applied to start the chemical reaction [1]. = − / (Eq.1) The main aim of the present investigation is connected with synthesis of polyols for urethane materials preparations. MW assisted reactions of glycolysis and transesterification were performed and compared with conventional synthesis. The investigation is focused on the utilization of bio-based rapeseed oil (RO) and recycled polyethylene terephatale (PET) for the proposed MW synthesis. The clear PET bottle waste was depolymerized by the glycolysis reaction with diethylene glycol (DEG). The additives of adipine acid (ADA) and glycerol (GL) were used. The hydroxyl group containing polyol was transesterified from RO. Zinc acetate (ZnAc) catalysis was used for both reactions. Both polyols were also transesterified together

Recycled Pet Flakes and Rapeseed Oil as Feedstock for Rigid Polyurethane Foams

Among different poly(ethylene terephthalate) (PET) recycling techniques chemical recycling is the most favourable and depolymerizing PET using glycolysis offers following advantage such as lower reagent amounts, lower temperatures and pressure [1, 2]. To prevent some of the PET polyol drawbacks such as incompatibility with the physical blowing agents and high viscosity, vegetable oil based polyols are introduced in polyol system [3]. Three bio/recycled polyols using recycled PET and rapeseed oil (RO) were successfully synthesized using continuous two-step method

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 productio