The Structural And Properties Of Polymer/Zirconium Phosphate (Phosphonate) Nanocomposites

a-Zirconium phosphate (a-ZrP) is a kind of cationic compounds. In addition to the layered structure, a-ZrP has a number of additional advantages, including a much higher ion exchange capacity, ease of dimensional control, ease of intercalation/exfoliation, and controllable/designable surface functionality. Thus, a-ZrP has a prospect of incalculable in the improvement of polymer. properties. Based on the previous studies, a-ZrP has been synthesized using the refluxed method and further modified by the n-butylamine to obtain the enlarger interlayer space. Then pea starch/a-zirconium phosphate (PS/ZrP) and chitosan/a-zirconium phosphate (CS/ZrP) nanocomposites have been prepared. The thesis focuses on the interfacial interaction between polymer matrix and nano-particles. The structure and properties of nanocomposites have also been discussed. And then a new type of layer zirconium phosphonate (zirconium glycine-N, N-dimethylphosphonate, abbreviated as ZGDMP), with the functional group-COOH has been synthesized. And pea starch/zirconium phosphonate (PS/BA-ZGDMP) and chitosan/zirconium phosphonate (CS/BA-ZGDMP) nanocomposites have been prepared. The interfacial interaction on the structure and properties has been discussed through the comparision.The main contents and results in this thesis are as follows:1. Glycerol-plasticized pea starch/a-zirconium phosphate (PS/ZrP) nanocomposite films with different loading levels of a-zirconium phosphate (a-ZrP) were prepared by a casting and solvent evaporation method. The effects of the a-zirconium phosphate on the structure and properties of the PS/ZrP films were characterized by Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and tensile testing. The results indicated that hydrogen bonds formed between pea starches (PS) and a-ZrP, which improved interface adhesion and the compatibility between PS and a-ZrP.2. A new type of layered zirconium glycine-N, N-dimethylphosphonate (abbreviated as ZGDMP), with enlarged interlayer d-spacing and the functional group-COOH, was prepared. ZGDMP was successfully intercalated by n-butylamine which further increased the d-spacing to 1.76 nm. The modified ZGDMP (hereafter BA-ZGDMP) was used as nanofiller in a glycerol-plasticized thermoplastic pea starch (PS) matrix. Compared with previous studies on a-ZrP-reinforced pea starch matrix, the present system of BA-ZGDMP reinforced pea starch (PS/BA-ZGDMP) presents two significant points:(i) the tensile strength was enhanced to 12.14 MPa, which was remarkably higher than that of the PS/ZrP system (9.44 MPa); and (ii) the moisture uptake in PS/BA-ZGDMP was reduced to 59.1%, which was lower than that of the PS/ZrP system (63.1%). These results can be attributed to the introduction of the polar carboxylate ions (-COO), which resulted in Van der Waals force as well as stronger hydrogen bonding, and stronger interfacial adhesion and interaction between the polar BA-ZGDMP and the polar starch matrix.3. The objective of this work is to prepare nanocomposite films of chitosan/a-zirconium phosphate (CS/ZrP) by casting process, using a-zirconium phosphate (a-ZrP) as nanofillers and chitosan as matrix. The effects of a-zirconium phosphate on the structure and properties of the nanocomposites were investigated. FT-IR revealed that a strong interaction between a-ZrP and chitosan formed during the film-forming process. The results from scanning electron microscope (SEM) and transmission electron microscope (TEM) indicated that a-ZrP uniformly dispersed and formed moderate exfoliated a-ZrP nanoplateletes in chitosan matrix. The parameter B calculated from tensile yield stress according to Pukanszky model was used to value the interfacial interaction between chitosan matrix and a-ZrP. The film with loading of 2 wt%α-ZrP had the highest B value (3.2), indicating the strongest interfacial interaction. 4. A new type of layer zirconium phosphonate (zirconium glycine-N, N-dimethylphosphonate, abbreviated as ZGDMP), with the functional group-COOH, has been successfully prepared and characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). In order to confirm the effect of the functional group-COOH on the structure and properties of composites, then a series of chitosan/zirconium phosphonate modified by n-butylamine (BA-ZGDMP) nanocomposite films were prepared by casting process. FTIR spectra suggested that strong interactions existed between BA-ZGDMP and chitosan matrix. Compared with neat CS film, the tensile strength (σb) and the elongation at break (εb) of the nanocomposite film were greatly improved by 35.1% and 15.6%, respectively, only with 1.0 wt% BA-ZGDMP loading. In addition, the BA-ZGDMP also improved the water resistance of the nanocomposites.