Synthesis And Properties Of Itaconic Acid Based And Biobased Polyamides

Nowadays, polyamides(PA), which are usually synthesized from petrochemicals, are essential in our daily life because of their outstanding properties such as high modulus, toughness, and abrasion resistance. However, with the depleting fossil resources and the related environmental issues brought by fossil feedstock utilization and consumption, it is very important and urgent for us to develop durable and high performance materials from renewable resources. During the last few decades, many bio-based polymers emerged as alternatives for petroleum-based polymers. Approaches like biotechnology (e.g., production of microbial polyesters), chemical modification of natural polymers, and polymerization of bio-based monomers have been used to generate bio-based polymersAmong these polyamides, several all-bio-based polyamides or partly bio-based polyamides were commercialized. A class of bio-based aliphatic polyamides (BDIS) was synthesized by melting copolycondensation from four biomass monomers:itaconic acid (I A), sebacic acid (SA),1, 10-decanediamine (DD), and 1,4-butanediamine (BD). BDIS was characterized by Fourier-transformed infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), X-ray diffraction spectroscopy (XRD), thermal analysis (TA) and mechanical tests. IA was introduced into the system in order to adjust the chemical structure and the aggregation structures of the BDIS polyamide. Thus, some new polyamides with tunable properties were obtained, such as semi-crystalline polyamide with relatively low melting point, glassy polyamide with excellent toughness, and even rubbery amorphous polyamide after hydration. The BDIS with 100% itaconic acid can even be dissolved in ethanol, which makes it possibly be used by coating and dipping methods. In vitro cytotoxicity tests showed that these polyamides are nontoxic towards mouse fibroblasts and have great potential in biomedical applications.Isothermal crystallization and non-isothermal crystallization of BDIS(IA-15%) were investigated by differential scanning calorimetry (DSC). The Avrami equation was used to describe the isothermal crystallization of BDIS polyamides. The modified Avrami equation, the modified Ozawa equation, and an equation combining the Avrami and Ozawa equations were used to describe the non-isothermal crystallization. The Avrami exponent n was found to be in the range of 2.21-2.79 for isothermal crystallization and 4.10-5.52 for non-isothermal crystallization.Polyamide is known to be hygroscopic, due to the amide groups repeated in the molecular main chain, which influence the stability of the size and properties of materials. In this part, the purpose of this work was to study the effects of three green solvents H2O, glycerol, and soybean oil on the properties of bio-based BDIS polyamides. The physical-chemical, mechanical and processability of the BDIS was influenced by the plasticizer content. The BDIS(IA-80%) polyamides showed considerable water absorption up to 22.0%. The amorphous BDIS(IA>50%) polyamide decreases the glass transition temperature directly and changes from the glassy state to the rubbery state after water soaking., the polyamide has an excellent recovery capability even though no chemical crosslink exists. The H2O-plasticized BDIS polyamides can be very useful for the preparation of physical water gel. Glycerol molecules formed hydrogen bonds with BDIS macromolecules and decreased the interaction among BDIS macromolecules. The soybean-oil-plasticized BDIS polyamides displayed excellent toughness, with elongation at break values reaching 650%.In order to improve the thermal stability, solvent resistance and mechanical properties of BDIS, the radiation crosslinking of BDIS has been investigated over a range of irradiation dose (50-250 kGy) with limited air. Due to the possible outdoor exposure in diverse applications, knowledge of the resistance to weather of BDIS materials is an important issue, not only for aesthetic aspects as in rapid yellowing, but also for changes in their properties. BDIS were exposed to an artificial ageing environment produced by a UV weathering device for different times. To follow and to evaluate this material ageing, several techniques such as FTIR, DSC, and XRD were employed to correlate the morphology and the mechanical properties.The BDIS and PCL/BDIS membranes were also prepared by electrospun and its properties were inverstigated. Anti-infection drug-loaded PCL/BDIS membranes were fabricated by electrospinning. Metronidazole (MNA), an antibiotic, was successfully incorporated into electrospun PCL/BDIS membranes at different concentrations. We systematically investigated the properties of the PCL/BDIS-MNA membranes. The dispersion of drug in the fibers and the physical-chemical of the PCL/BDIS-MNA membranes with different drug contents, drug release profiles, antibacterial function and biodegradability of the membranes were investigated. By comparing the comprehensive properties of the electrospun membranes, drug loaded membranes were effective in preventing the colonization of bacteria and infection.