Research On The Interface Of Polymer Composites

Interface research has an important effect on the properties and application of the polymer composites. More and more people pay their attention to this area.This paper studies the interface of lignin/phenol formaldehyde(PF), CaCO3/poly (ethylene terephthalate) (PET), and CaCO3/polyethylene glycol phosphate (PGP).The first chapter describes two routes for improving the potential for partially replacing phenol with lignin in PF resin. The first method is the refinement of ligninsulphonate. The product prepared by the two-step sulfonation has a higher sulfonation degree, purity, and lower sugar content. The number of the polar function groups of lignin is increased, so it has the stronger interaction with PF. In the second method, phenolation and three-step polymerization were combined to increase the reactivity of black liquor lignin. The number of covalent bonds is increased between PF resin and lignin. Temperature stability, infrared and ultraviolet radiation resistances of the resins prepared by the two methods are both improved.Due to the reaction of CaCO3 with terephthalic acid (TPA), the interaction of CaCO3 and PET in the compound prepared by the in-situ polymerization is weak. PGP solves the main problems: the reaction of CaCO3 with TPA, the agglomeration of CaCO3 nanoparticles, and the morphology control of CaCO3 nanoparticles. PGP provides a large of hydroxy groups which can form covalent bonds with carboxyl groups of PET during the polymerization, enabling CaCO3 nanoparticles to attach to PET matrix via the covalent bond. Based on these researches, stearic acid (SA) was modified on the surface of PGP-CaCO3 nanoparticles by the post-treatment, and the hydrophobic CaCO3 is obtained. This kind of the hydrophobic CaCO3 has the better compatibility with the polymer, which can be filled in PET at the process of polycondensation. The two kinds of nanocomposite exhibite a better dispersion of small primary nanoparticles, a higher polymerization degree, a better thermal stability and lower carboxyl end group content.In the third chapter, the interface of PGP and CaCO3 is studied. PGP is modified on calcite surface via chemical bond,which controls and tunes the growth of CaCO3. The nanoparticles have a better dispersion in ethylene glycol. We discuss the influence of the experimental conditions on the dispersion. Based on this, hydrophobic CaCO3 was prepared at room temperature via a carbonization route in the presence of SA and PGP. FTIR demonstrates that SA and PGP are modified on CaCO3 surface via chemical bonds. The effects of the additives on the surface hydrophobicity of CaCO3 are examined. The cooperative interaction of SA and PGP at the interface plays a key role in the formation of the hydrophobic CaCO3. The modified CaCO3 with the contact angle of 106°is used to steady the emulsion of water and n-hexanol. We discuss the influence of the surfactant, time and the electrolyte on the stability of the Pickering emulsion.