Study On The Molecular Design, Synthesis, And Porperties Of Novel Biobased Crosslinkable Polyamides

The chemical industry has been developing since the past centuryusing petroleum as its primary feedstock. However, with an exponentialgrowth in the demand for fossil raw materials today, industry revolutionbecome definitely reliable on fossil resources to produce the fuels,chemicals and polymers required for modern life. Meanwhile, we have toface the most critical challenges ever of fossil resource depletion andproliferation of global climate changing emissions, pollutant as well assolid wastes and find ways out. While polymer industry is recognized ashuge energy and raw material consuming and discharges enormousamounts of wastes and effluents, polymer from renewable resources, suchas biomass, can significantly cut down greenhouse gas (GHG) emissionsand save fossil energy use today as compared with conventionalpetrochemical-based polymers. Therefore, the development of biomass feedstock provides a feasible solution. Biomass is a feasible substitute,providing many of the same chemical building blocks-plus others thatpetrochemicals cannot-which are required to fabricate durable andhigh-performance materials.Herein, we report the successful simple synthesis of uniquebio-based crosslinkable polyamides by carrying out catalyst-free meltingcopolycondensation of four monomers derived from large-scaled biomassfeedstock: sebacic acid (SA), itaconic acid (IA),1,10-diaminodecane(DD) and1,4-diaminobutane (BD). The chemical and physical propertiesof the resultant copolyamide poly (buta-co-deca) methylene(itaconic-co-sebac) amides (BDIS) have been investigated.This novel material was characterized by nuclear magneticresonance spectroscopy (NMR), Fourier-transformed infraredspectroscopy (FT-IR), differential scanning calorimetry (DSC), thermalanalysis (TA), mechanical tests, X-ray diffraction spectroscopy (XRD)and hydration experiments. We demonstrate that the chemical structure,morphology and physical integrity of the synthesized copolyamides canbe tuned by simply varying the initial monomer feed ratio. It is porvedthat the pendent C=C double bond of itaconic acid plays a crucial role incontrolling and tuning the molecular structure and the correspondingproperpties of the BDISs. This new BDIS biobased polyamides displayversatility and tunablity in mechanical properties as determined by the chemical structure of the copolyamides.The hydration and plastification of the BDIS by water were exploredby us. It is noted that the water drastically depresses the glass transitiontemperature of the BDIS polyamides and has a significant effect on themechanical properties of BDISs.The BDIS was crosslinked by two approaches: thermal crosslinkingand radiation. The structures and properties of corresponding crosslinkedBDIS were characterized. The BDIS nanofiber was also prepared byelectrospun and its properties were inverstigated.Meanwhile, this work studies the crystallization kinetics and meltingbehaviors of the BDIS biobased crosslinkable polyamides under bothisothermal and non-isothermal conditions. The isothermal crystallizationkinetics is described by the Avrami equation while under thenon-isothermal conditions, the crystallization kinetics are explored by theAvrami equation modified by Jeziorny, the Ozawa theory, the modifiedOzawa equation and a combined Avrami and Ozawa equation.