Nanocomposites of poly(lactic acid) (PLA)/poly(butylene adipate‐co‐terephthalate) (PBAT) blends with multiwalled carbon nanotubes (MWCNTs) were prepared and their morphology, as well as electrical, mechanical, and thermal properties were investigated. The motivation of this work is to prepare electrically conductive and environmentally benign polymer nanocomposites using biodegradable PLA/PBAT blends. The composites were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning and transmission electron microscopy, tensile and microindentation tests, and thermogravimetric analyses (TGA). Volume resistivity and resistance to tensile deformation were measured for electrical characterization. The nanocomposites films were integrated into an electrical circuit to confirm their electrical conductivity. The FTIR spectra revealed the physical mixing between the polymer matrix and the filler. TEM micrographs suggested selective localization of MWCNTs in the PBAT phase with partial agglomeration forming a co‐continuous morphology. TGA and derivative thermogravimetric curves suggested the overall decreasing thermal stability of composites than pure polymer blends regardless of the effects on individual blend components. A relatively low electrical percolation threshold (around 1 wt% of the fillers) compared to the literature works was achieved. Increasing electrical resistance of nanocomposites upon tensile deformation suggested their possibility of piezoresistive properties. Furthermore, the overall mechanical performance (i.e., elastic modulus, tensile strength, and hardness) of the materials was found to improve with increasing filler content.
The present work features some simple methods of preparing pure hydroxyapatite nanoparticles (nano-HAp), a useful biomaterial, via various wet chemical methods and using biogenic sources such as eggshells and animal bone. The nano-HAp hence prepared was subsequently characterized by FTIR spectroscopy and XRD technique. The FTIR spectra confirmed the presence of PO43- and OH- ions as major functional groups in the prepared material, with some additional peaks implying the presence of CO3- ions and adsorbed water molecules. The XRD patterns, in agreement with the JCPDS 09-432 data, demonstrated the crystalline nature of the nano-HAp and confirmed the phase as being apatite. The average grain diameter of the nanocrystallites was found in the range of 15-30 nm. The preparatory methods depicted herein can be easily employed in ordinary high school laboratories having basic facilities such as availability of distilled water, some handy glasswares, common laboratory chemicals and instruments such as balance, hot air oven and furnace.
BIBECHANA 18 (2021) 83-90
Polymers are made from the monomers that are used for packaging purposes. The degradation of polymers can take place either abiotic or biotic pathways. Abiotic pathway occurs from thermal, photo-degradation, and catalytic methods whereas, biotic occurs in presence of different types of microorganisms. The degradation of polymers (polyethylene and polylactic acid) was explained by the thermal, catalytic, and biodegradation process. The thermal degradation of polyethylene and polylactic acid was explained by the thermogravimetric analysis (TGA) curve. Catalysts such as zeolites and amorphous silica-alumina are used for the degradation of polyethylene whereas, tin for polylactic acid. Microorganisms such as bacteria, fungus, and actinomycetes help for the degradation of polyethylene and polylactic acid.
BIBECHANA 18 (2021) 240-253
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