Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and their composite were prepared by melt compounding. Maleic anhydride grafted PLA (PLA-g-MA) was used as a compatibilizer. With the addition of PBAT into PLA, elongation at break and impact strength increased but tensile strength and modulus decreased. Incorporating PLA-g-MA into PLA/PBAT blend improved the mechanical properties of the blend. Tensile properties of blown film prepared from the compatibilized PLA/PBAT blend were better than those of the uncompatibilized PLA/PBAT blend. Incorporating CaCO 3 resulted in increased tensile strength and modulus of the film prepared from the compatibilized blend.
Poly (lactic acid) (PLA), a biodegradable polyester, derived from renewable resources has been widely used in biomedical and packaging applications. However, the shortcomings for using PLA including its processing instability, low melt viscosity and low flexibility limited its applications. To overcome these shortcomings, poly (butylene adipate-co-terephthalate) (PBAT) was blended with PLA to improve ductility of PLA. However, PLA and PBAT are incompatible. Maleic anhydride grafted PLA (PLA-g-MA) was used to enhance the compatibility of the blends. Moreover, the blend of PLA and PBAT exhibited higher elongation at break but lower tensile strength and Young’s modulus than the pure PLA due to the addition of a ductile phase. Therefore, the addition of calcium carbonate (CaCO3) to PLA/PBAT blends led to achieve balanced properties of the blends. In this study, PLA/PBAT blends and PLA/PBAT/CaCO3 composites were prepared by an internal mixer. PLA-g-MA was as a compatibilizer. Mechanical properties and rheological properties of the blend and composites were investigated. In addition, morphologies of PLA/PBAT blend and their composites were observed by a scanning electron microscope (SEM). The incorporation of PBAT gave rise to remarkable improvement in elongation at break and impact strength of PLA. Tensile strength of PLA/PBAT blend was enhanced by adding PLA-g-MA. With increasing CaCO3 content, Young’s modulus of the composites increased while tensile strength and elongation at break decreased.
Poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blend and its composite were prepared by melt blending method. Maleic anhydride grafted PLA (PLA-g-MA) prepared in-house was used as a compatibilizer to enhance the interfacial adhesion between PLA and PBAT and also to improve the dispersion of calcium carbonate (CaCO3) in polymer matrices. Increasing PBAT content (10-30 wt%) resulted in the improvement of elongation at break and impact strength of PLA. Tensile strength, Young’s modulus, and impact strength of PLA/PBAT blend improved with the presence of PLA-g-MA due to enhanced interfacial adhesion between PLA and PBAT. As CaCO3 (5 wt%) was incorporated into the compatibilized blend, tensile strength, Young’s modulus, and impact strength insignificantly changed while elongation at break decreased.
In this study, titania–silica oxides (TixSiy oxides) were successfully prepared via the sol–gel technique. The Ti and Si precursors were titanium (IV), isopropoxide (TTIP), and tetraethylorthosilicate (TEOS), respectively. In this work, the effects of pH and the Ti/Si atomic ratio of titanium–silicon binary oxide (TixSiy) on the structural characteristics of TixSiy oxide are reported. 29Si solid-state NMR and FTIR were used to validate the chemical structure of TixSiy oxide. The structural characteristics of TixSiy oxide were investigated using X-ray diffraction, XRF, Fe-SEM, diffraction particle size analysis, and nitrogen adsorption measurements. By applying X-ray absorption spectroscopy (XAS) obtained from synchrotron light sources, the qualitative characterization of the Ti-O-Si and Ti-O-Ti bonds in Ti-Si oxides was proposed.Some Si atoms in the SiO2 network were replaced by Ti atoms, suggesting that Si-O-Ti bonds were formed as a result of the synthesis accomplished using the sol–gel technique described in this article. Upon increasing the pH to alkaline conditions (pH 9.0 and 10.0), the nanoparticles acquired a more spherical shape, and their size distribution became more uniform, resulting in an acceptable nanostructure. TixSiy oxide nanoparticles were largely spherical in shape, and agglomeration was minimized. However, the Ti50Si50 oxide particles at pH 10.0 become nano-sized and agglomerated. The presence of a significant pre-edge feature in the spectra of Ti50Si50 oxide samples implied that a higher fraction of Ti atoms occupied tetrahedral symmetry locations, as predicted in samples where Ti directly substituted Si. The proportion of Ti atoms in a tetrahedral environment agreed with the value of 1.83 given for the Ti-O bond distance in TixSiy oxides produced at pH 9.0 using extended X-ray absorption fine structure (EXAFS) analysis. Photocatalysis was improved by adding 3% wt TiO2, SiO2, and TixSiy oxide to the PLA film matrix. TiO2 was more effective than Ti50Si50 pH 9.0, Ti50Si50 pH 10.0, Ti50Si50 pH 8.0, and SiO2 in degrading methylene blue (MB). The most effective method to degrade MB was TiO2> Ti70Si30 > Ti50Si50> Ti40Si60 > SiO2. Under these conditions, PLA/ Ti70Si30 improved the effectiveness of the photocatalytic activity of PLA.
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