Polymers obtained from renewable sources are gaining popularity over their petroleum based counter parts in recent years due to their capability to address the environmental pollution related concerns emanating from the widespread usage of synthetic polymers. Even though the polymers from renewable sources are attractive in an environmental point of view, some of the property limitations and the high cost of these materials pose limitations for their extensive commercial applications. These aspects opened the door for a large chunk of research activities in development of polyblends and composites containing polymers from renewable sources as one of the components. Poly (lactic acid) (PLA) is one of the most discussed and commercialized polymer originated from renewable resources. Even though it has many useful properties, certain disadvantages like high brittleness, low impact resistance etc. limit the wide spread commercialization of PLA. In this review article, the recent research activities which are aimed to fill this gap by various modifications of PLA are discussed with special emphasis on the latest research advancements in the field of biodegradable and non biodegradable systems containing PLA.

The nylon 66/nano-CaCO3 composites were prepared by melt blending on a twin-screw extruder. Scanning electron microscopy (SEM), polarized light microscopy (PLM), thermal loss (TGA) and differential scanning calorimetry (DSC) The effects of nanometer calcium carbonate on the polycrystalline behavior and thermal properties of nylon 66/nano CaCO3 composites were investigated. The results show that the nanometer calcium carbonate particles are dispersed in the nylon 66 matrix and exist in the form of aggregates. The nanometer calcium carbonate has the effect of heterogeneous nucleation, which can reduce the size of the spherules. The decomposition temperature of the nylon 66 is 400 ℃, the addition of nano-CaCO3 to reduce the decomposition temperature. At the same time, DSC test showed that the β-crystalline form in the material reduced the melting temperature of the material. The addition of nano-CaCO3 in the nylon 66 matrix resulted in the decrease of the crystallization temperature and the increase of the half-height width of the endothermic peak. The lower the crystallization temperature, the wider the crystallization temperature range.

Lead sulfide (PbS) is an important IV-VI semiconductor material with narrow bandwidth and wide wave width, which attracts people's attention. Nano-level PbS has many novel optoelectronic properties and has a wide range of applications in the field of optoelectronics, such as infrared optoelectronic devices, photovoltaic devices, light-emitting devices and display devices. In this paper, Pbs is produced by solvent thermal method by using lead acetate as lead source, sulfur power as sulfur source, ethylene glycol as solvent, and acetic acid to provide acidic environment. The reaction acidity, type of lead source, amount of sulfur source and other aspects will be explored. The products obtained under different conditions were characterized by X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM). The results showed that PbS produced at 140°C for 24 hours, using 14mL ethylene glycol and 1.2mL acetic acid has the best morphology. It has a non-planar six-arm symmetrical structure. Finally, we prepare the lead sulfide composite Ni/PbS, and characterized it.

The porous carbon/Ni nanoparticle composite was prepared by a freeze-drying method using NaCl as the template. It was applied in the effect of the concentration, adsorption time, and temperature of adsorption on the adsorption behavior. The kinetic model and the adsorption isothermic fitting results show that the adsorption behavior fits with the pseudo-secondary dynamics and the Langmuir isothermal model, indicating that the adsorption process is monolayer adsorption. Thermodynamic results indicate that the adsorption process is spontaneous physicochemical adsorption. The fitting showed that the porous carbon/Ni nanoparticle composites reach 217.17 mg·g^-1, at 313 K indicates good adsorption for Congo red.

Xylene isomers are notorious chemical hazards, and their efficient removal from water solutions is still challenging. The current study reports a polymer nanocomposite as a potential adsorbent for successfully removing dissolved xylene isomers from contaminated water. Polystyrene-1D multiwall carbon nanotube nanocomposite (PS-MWCNT) adsorbent was prepared using the one-step bulk polymerization method. Mesoporous PS-MWCNT was prepared using the nano-crystallization phase separation method. The sulfonation of the mesoporous PS-MWCNT nanocomposites was carried out by treating the samples with concentrated sulfuric acid at elevated temperatures. The sulfonated PS-MWCNT (HO₃S-PS-MWCNT) was found to be a potential adsorbent for dissolved xylene isomers from water solution. In addition, the HO₃S-PS-MWCNT can be efficiently recycled for up to 10 consecutive cycles with negligible decline in adsorption values. The exhibited equilibrium adsorption, rate of adsorption, and rapid regeneration of the HO₃S-PS-MWCNT are clear indications for the possibility of practical utilization of these adsorbents in large-scale water treatment plants.