Water vapor permeable polyurethane films based on the hyperbranched aminoethers of boric acid

The hyperbranched polymers have drawn intensive attention in the design of macromolecules and functional materials because of their unique physical and chemical properties resulting from the branched architecture and the high number of functional groups. In the present study, by means of light scattering, viscosimetry, thermomechanical analysis, tensile stress–strain, mechanical loss tangent and water vapor permeability measurements, we demonstrate the hierarchical macromolecular organization of organoboron polyurethanes synthesized using sterically hindered amino ethers (AEBA) of boric acid. It is shown that the water vapor permeability of polyurethanes obtained on the basis of sterically hindered aminoethers of boric acid is due to the peculiarities of the chemical structure of AEBA, which can exhibit an ionomeric nature and the presence of steric hindrances created in the hyperbranched structure of AEBA, which can lead to an increase in free volume in such polyurethanes.

It is shown that the water vapor permeability of polyurethanes obtained on the basis of sterically hindered aminoethers of boric acid is due to the peculiarities of the chemical structure of AEBA.

Synthesis, Characterization and Preliminary Investigation of Blood Compatibility of Novel Epoxy-modified Polyurethane Networks

To prepare elastomers with acceptable physical properties and good blood compatibility, polyurethane networks were synthesized via crosslinking reaction of epoxy-terminated polyurethane prepolymers (EUPs) and hexamethylene diamine. EUPs were prepared by reacting glycidol and NCO-terminated polyurethanes. All new materials were characterized by conventional spectroscopic methods and properties were evaluated and correlated to their structure. Cytotoxcicity evaluation for the films of samples based on mouse fibroblasts (L929) revealed that these elastomers posed no threat to these cells. In vitro platelet-rich plasma contact test showed reduced number of adhered platelets on the surface of the films, particularly for those with maximum crystallinity and microphase structures and high hydrophilicity. The results obtained implied the potential for the utilization of these elastomers in biomedical applications.

Preparation and ecotoxicity assessment of new biodegradable polyurethane foams

Flexible biodegradable polyurethane foams (BIO-PUR) were prepared by a one-shot process using commercially available coreactants and modified by substituting biodegradable additive based on the acetylated starch (AS), acetylcellulose (AC), 2-hydroxyethylcellulose (HEC) and carboxymethylcellulose sodium salt (CMC) for 5 or 10 wt% of commercial polyether polyol. The BIO-PUR foams were characterized by FTIR, TGA and polarization microscopy. Ecotoxicity of BIO-PUR foams freshwater extracts was evaluated using the alternative crustacean toxicity test Thamnotoxkit F. Values of toxicity were expressed as percentage mortality of the instars II-III larvae of freshwater fairy shrimps (Thamnocephalus platyurus) dependence on the effect criterion of the respective assay. The leaches of BIO-PUR foams modified with 5 or 10 wt% of HEC showed higher toxicity then other BIO-PUR foams, whereas leaches of BIO-PUR with 5wt% of AS and 10wt% of AC were even less toxic than REF. PUR foam.

Novel Polyurethane Electrical Insulator Coatings Based on Amide-Ester-Ether Polyols Derived from Castor Oil and Re-cycled Poly(ethylene terphthalate)

In order to utilize renewable resource raw materials as well as trying to recycle polymeric materials, three new polyols (PEEA1-3) were prepared. Bottle grade recycled poly(ethylene terphthalate) was subjected to transesterification and an amidation reaction with different molecular weights of poly(ethylene glycol) and diethanol amine. The intermediate hydroxyl-terminated compounds were chain extended via an esterification reaction with adipic acid and the products were reacted with castor oil. Polyurethane networks were prepared through the reaction of PEEA1-3 with librated isocyanate groups of a blocked isocyanate curing agent made from trimethylol propane, toluene diisocyanate and N-methyl aniline. All of the starting materials and final cured films were characterized by conventional methods. The curing condition was optimized via gel content measurements. The crosslink density of the samples was determined via an equilibrium swelling method, using the Flory-Rehner equations. The effects of structural parameters on the physical, electrical, mechanical, and dynamic mechanical properties of the polyurethane coatings were evaluated. Investigation of the results showed that the prepared green coatings have environmental benefits as well as high performance as metal insulator coatings.