Abstrato

Modification of epoxy resins by thermoplastic polyurethanes based on polycarbonate diol

Milorad Ninkovic

 The modification of epoxy resins with thermoplastic polyurethanes with good elastic characteristics was done in this thesis. The impact of synthetic polyurethane based on polycarbonate diol (5,10, and 15% by weight in proportion to epoxy), as well as the proportion of rigid elastomeric segments (20, 25, and 30% by weight), on the epoxy composite networking process was investigated. A differential scanning calorimeter (DSC Q20 TA Instruments) was used to evaluate the networking of epoxy hybrid materials at three different heating speeds (5, 10 and 20oC/min). Thermoplastic polyurethane films with varying percentages of hard segments (20, 25, and 30% by weight) were utilised to modify epoxy resins. In different weight percentages relative to the resin,  synthesised polyurethane elastomers were added to the epoxy (5, 10 and 15 wt percent ). A composite mixture was stirred using a magnetic stirrer at 60oC for 2 hours to blend elastomers and epoxides. The mixture is then agitated for another 20 minutes in an ultrasonic bath for greater homogeneity. The Jeffamine D-2000 cross-linker was then added to the binary component that had been created. The new reaction mixture was then vacuum dried for an hour to eliminate any remaining CO2 bubbles. The reaction mixture is put onto polypropylene plates to make films. The polypropylene plates were placed in the dryer after 24 hours at room temperature, where the process of networking modified epoxy resins lasted an additional 4 hours at TPUs (thermoplastic polyurethane elastomers) are segmented copolymers comprising urethane and alternately dispersed flexible soft segments and more stiff hard segments. Polyether and polycarbonate diols are used as soft segments in traditional TPUs polyester, whereas aliphatic diols (primarily butane-1,4-diol (BD)) and aromatic (primarily 1,1′-methanediylbis(4-isocyanatobenzene) (MDI)) or aliphatic diisocyanates (mostly 1,1′-methanediylbis(4-isocyanato) . TPUs are widely used in a variety of fields, including medicine, footwear, and the car sector, but new materials with improved characteristics and versatility are still needed. As a result, alterations to standard TPUs are made to their main chain, side chains, and the polymer surface itself. My colleagues and I recently demonstrated TPUs that had been adjusted in the main chain. 2,2′-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol (diol OSOE), 2,2′-[oxybis(benzene-1,4-diylsulfanediyl)]diethanol, or 2,2′-[sulfanediylbis(benzene-1,4-diylsulfanediyl)]diethanol commercial diisocyanates, such as MDI, diethanol, Commercial polymer diols, such as aliphatic polyether diol of Mn=1000g/molMn=1000g/mol and aliphatic polycarbonate diol of Mn = 2000 g/mol, and HMDI and 1,6-diisocyanatohexane (HDI) (PCD). Thermal stability and tensile strength (up to 44 MPa) were found to be quite excellent in these polymers. TPUs based on aliphatic diisocyanates were also resistant to yellowing and showed good transparency in some circumstances. When compared to polymers made using conventional chain extenders, those made with sulfur-containing chain extenders had greater adhesion qualities to metals as well as increased refractive index and transparency.