Synthesis and characterization of lactic acid-based elastomers

Sammanfattning: Synthesized polymer from bio-based and renewable resources reported as an attractive substitution for fossil-fuel based polymers. Therefore, this work has focused on using sustainable material for production of elastomers to reduce the environmental impact of fossil-based elastomers and overcome the shortage of non-renewable fuels. In this research (as thesis work) bio-based elastomers (resins synthesized by reacting of lactic acid with 1,4-butanediol in presence of toluene and methanesulfonic acid as solvent and catalyst, respectively. To trace the reaction, the Fourier transform infrared (FT-IR) spectrometer was used for structural characterization of the products. Furthermore, the degree of reaction followed by measuring of the acid value using alkali titration method. To achieve the desirable results, both condensed resins were reacted with caprolactone for ring opening polymerization. The produced resins were finally functionalized using methacrylic anhydride and the structures and thermal properties of the produced resin were characterized using FT-IR, DSC and TGA. In addition, the viscoelastic properties of the resins were investigated using dynamic mechanical analysis (DMA); and elasticity and viscosity of the elastomers measured using tensile testing machine and viscometer, respectively. The important result such as viscosity showed the resin with chain length n= 5 had higher viscosity when compared to the resin chain length n=3. This makes the resin (n=5) suitable for applications that need high viscosities. The resin with chain length n=3 had lower viscosity that is suitable for processing at room temperature. Furthermore, the tensile strength results show maximum elongation for resin with chain length n=3 is almost double compared to resin with chain length n=5. The results showed that these bio-based resins are compatible with petrochemical-based resins, due to desirable rubbery properties, melting temperature, also acceptable viscosity, and other good mechanical properties as will be mentioned below.