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In this article, a series of oxidized pea starch/chitosan (OPS/CS) blend films were prepared by a casting and solvent evaporation method. The structure, thermal behavior, and mechanical properties of the films were investigated by means of Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and tensile testing. The results suggested that, in addition to hydrogen bonding, the interactions between OPS and CS molecules were enhanced by the formation of electrostatic interaction between the negatively charged carboxyl groups on OPS and the positively charged amino groups on CS. Compared with the pea starch/chitosan (PS/CS) blend films, OPS/CS blend films exhibited significantly higher tensile strength with significantly lower elongation at break. Moreover, incorporation of CS into the OPS matrix also led to a decrease in moisture uptake by the composite film. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Nano-fillers play an important role in the final structure and properties of nanocomposites. The objective of the work presented here was to prepare nanocomposite films of chitosan/α-zirconium phosphate using a casting process, with α-zirconium phosphate (α-ZrP) as nano-filler and chitosan as matrix. The effects of α-ZrP on the structure and properties of the nanocomposites were investigated. X-ray diffraction patterns showed that α-ZrP crystals were intercalated by n-butylamine. The results from scanning electron microscopy and transmission electron microscopy indicated that α-ZrP could be uniformly dispersed in the chitosan matrix when α-ZrP loading in the composites was less than 2 wt%. A strong interaction between α-ZrP and chitosan formed during the film-forming process. Tensile testing showed that the tensile strength and elongation at break of nanocomposite films achieved maximum values of 61.6 MPa and 58.1%, respectively, when α-ZrP loading was 2 wt%. The parameter B calculated from tensile yield stress according to the Pukanszky model was used to estimate the interfacial interaction between the chitosan matrix and α-ZrP. Films with a loading of 2 wt% α-ZrP had the highest B value (3.2), indicating the strongest interfacial interaction. The moisture uptake of the nanocomposites was reduced with addition of α-ZrP. It can be concluded that α-ZrP as nano-filler in a chitosan matrix can enhance the mechanical properties of nanocomposites due to the strong interactions between α-ZrP and chitosan. Copyright © 2010 Society of Chemical Industry

A new type of layered zirconium glycine-N,N-dimethylphosphonate (ZGDMP), with enlarged interlayer d-spacing and a polar carboxylate group (COO–), was prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). ZGDMP was intercalated by n-butylamine which further increased the d-spacing to 1.76 nm. The modified ZGDMP (hereafter BA-ZGDMP) was used as a nanofiller in a glycerol-plasticized thermoplastic pea starch (PS) matrix. Compared with previous studies on PS/α-ZrP, 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 higher than that of the PS/ZrP system (9.44 MPa); and (ii) the moisture uptake of 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 functional carboxylate groups, which resulted in Van der Waals forces, stronger hydrogen bonding, and stronger interfacial adhesion and interaction between the polar BA-ZGDMP and the polar starch matrix. POLYM. COMPOS., 31:1938–1946, 2010. © 2010 Society of Plastics Engineers.

The grafting of 4-vinyl pyridine (4-VP) onto konjac glucomannan (KGM) by ammonium persulfate (APS) as the initiator was studied in an acid aqueous solution under an inert atmosphere. The grafting ratio (G%) and grafting efficiency (E%) were evaluated comparatively. The dependence of these parameters on the initiator concentration, sulfuric acid concentration, ratio of monomer to KGM, temperature, and reaction time was also investigated. Under conditions of [KGM] = 1.00 g/L, [APS] = 1.00 × 10−2 mol/L, [4-VP] = 9.32 × 10−2 mol/L, [H+] = 5.00 × 10−2 mol/L, temperature = 35°C, and time = 120 min, the optimum G% and E% were 307.27 and 52.75%, respectively. The proof of grafting was obtained from thermogravimetric analysis and infrared spectra. Preliminary research of the graft's adsorption capacity for heavy-metal ions [Cr(VI), Cu(II), Pb(II), and Cd(II)] was done. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009