Study On The Synthesis And Application Of Poly {2,6-Diimidazo[4,5:4'5'-E]Pyridinylene-1,4(2,5-Dihydroxy)Phenylene} Nanoparticles

The rigid-rod polymer family--polymer poly {2,6-diimidazo [4,5-b:4'5'-e]pyridinylene-1,4(2,5-dihydroxy)phenylene}(PIPD) has the ability to form hydrogen bonds between adjacent chains and is characterized by high modulus,high tensile strength and high thermal stability.So far,the study on PIPD was concentrated on the fiber spun from the polymerization solution,the other field works of PIPD were seldom reported.In this dissertation,woks on the synthesis and application of PIPD nanoparticles had been carried out.Regulated PIPD nanoparticles were obtained by in-situ polymerization in presence of inorganic nano-materials. The crystallization behavior,tensile and thermal properties of engineering materials/PIPD blends,such as nylon6/PIPD,PIPD/nilon 66 and epoxy/PIPD blends were investigated.1.PIPD nanoparticles were prepared by in-situ polymerization, especially when the polycondensation was carried out in presence of inorganic nano-materials,such as functionalized carbon nanotubes(f-CNTs) and nano calcium carbonate(nano-CaCO₃).Through the scanning electron microscope(SEM),transmission electron microscopy(TEM), thermogravimetric analysis(TG),energy dispersive x-ray Spectrometer (EDX) characertization,the effect of the inorganic nano-materials and solvent were investigated.The results suggested that the inorganic materials acted somewhat like heterogeneous nucleation agents and the size of f-CNTs-PIPD nanoparticles grew with increasing f-CNTs contents. Much more regulated nanoparticles could be obtained after the MSA solvent treatment.2.The blends of PIPD/nylon 6 and blends of PIPD/nilon 66 have been prepared via a controlled polymer solution crystallization method.The crystallization behavior of the nylon/PIPD blends were investigated using differential scanning calorimetry(DSC),x-ray diffraction(XRD),and polarizing microscopy(PLM).It showed that thepresence of PIPD reduced the crystallization temperature,degree of crystallinity,and the perfect of crystal.In PIPD/nylon 6 blends,the addition of PIPD nanoparticles was benefit to growing theα-form of nylon 6.In PIPD/nilon 66 blends,the addition of PIPD not only made the crystal cell of nylon 66 increased,but also madeα-form of nylon 66 growed on the(100) side easily.3.The blends of PIPD/Epoxy have been prepared via a polymer solution method.The tensile and thermal properties of the blends were investigated by using DMTA and SEM and tensile properties testing methods.When the content of PIPD nanoparticles was 0.7wt%,the tensile strength and tensile modulous of e PIPD/poxyblends were increased by 195%and 66.13%,respectively.The strengthening and toughening effects of PIPD nanoparticles were remarkablely.