Zinc oxide as a new catalyst for poly(lactic acid)/maleated polypropylene reactive blending: an approach to enhance miscibility and mechanical properties
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引用次数: 0
Abstract
To eliminate the defects of polylactic acid (PLA), maleated polypropylene (MAPP) as a toughener in the presence of a new exchange catalyst, ZnO, was applied. By keeping the amount of MAPP constant, samples with different amounts of ZnO nanoparticles (NPs) were prepared and studied by tensile, Izod, differential scanning calorimetry (DSC), melt flow index (MFI), water droplet contact angle (WDCA), transition electron microscopy (TEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analyses. In comparison to neat PLA, mechanical tests showed that with a slight decrease in elastic modulus and tensile strength, elongation at break and impact strength values increased more than three times for the sample containing 0.125 wt.% of catalyst. DSC analysis indicated that with the catalyst present, the Tg values of both polymers became closer to one another. Additionally, the absence of cold crystallization in PLA and the reduction in Tm and crystallinity of both polymers are evident factors contributing to the best miscibility of the reactive blend. MFI evaluation displayed decrease in viscosity and WDCA measurement indicated the creation of more polar groups on the surfaces of samples containing ZnO. TEM, EDX and XRD analyses proved the appropriate distribution and dispersion of NPs within the blend matrix as well as obvious decrease in the crystallinity of the resulting alloy. All these results demonstrate the better performance of exchange (esterification and transesterification) reactions between the active groups of both polymers (with ZnO presence) and the formation of PLA–MAPP copolymers, resulting in better miscibility and mechanical properties.
Graphical abstract
Possible transesterification reactions during melt blending of PLA and MAPP.
期刊介绍:
Original research on all aspects of polymer science, engineering and technology, including nanotechnology
Presents original research articles on all aspects of polymer science, engineering and technology
Coverage extends to such topics as nanotechnology, biotechnology and information technology
The English-language journal of the Polymer Society of Korea
Macromolecular Research is a scientific journal published monthly by the Polymer Society of Korea. Macromolecular Research publishes original researches on all aspects of polymer science, engineering, and technology as well as new emerging technologies using polymeric materials including nanotechnology, biotechnology, and information technology in forms of Articles, Communications, Notes, Reviews, and Feature articles.