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In the work, the poly(lactic acid) (PLA)/poly (ethylene-butylacrylate-glycidyl methacrylate) (PTW) blends were prepared by melt compounding. PTW as a toughening agent for PLA, the PLA/PTW blends had good compatibility due to the chemical reaction between the epoxy groups of PTW and the end group of PLA during the blending process. With increasing PTW content from 0 to 20%, the impact strength of PLA/PTW blends was enhanced from 4.6 to 54.1 kJ/m2 and the elongation at break was increased from 5.6% to 270%. The scanning electron microscopy (SEM) images of the impact fracture surfaces showed a large amount of cavities and plastic deformation, which caused by the elastomer and the interfacial adhesion enhanced through the interaction of the terminal functional groups. That was the reason that the toughness of PLA was increased. Finally, proteinase K-catalyzed degradation tests shown that the addition of PTW was beneficial to the biodegradation of PLA and reduced environmental pollution.

Sevoflurane (Sev) anesthesia is widely used in pediatrics due to its low blood-gas partition coefficient and lack of pungency. However, Sev treatment may lead to cognitive dysfunction in later life. The current study administered Sev to neonatal rats to investigate the effects of Sev treatment on cognitive performance in adulthood. In total, 6-day-old rats received 3% Sev for 2 h daily for 3 consecutive days. The cognitive function of rats in adulthood was evaluated in 56-day-old rats by Morris water maze test. The hippocampal neuron morphology was observed by Nissl staining. Hippocampal brain-derived neurotrophic factor (BDNF) levels were measured by ELISA. The protein expression of protein kinase A (PKA), cAMP response element binding protein (CREB), phosphorylated-CREB (p-CREB) and BDNF in hippocampus were assessed by western blotting. The water maze results demonstrated that neonatal treatment with Sev resulted in a significant impairment of cognition in 56-day-old adult rats. Behavioral analysis revealed that Sev treatment increased latency to first pass the platform and decreased residence in target quadrants and across platform frequency compared with the control group in Morris water maze tests. Furthermore, compared with the control group, neonatal exposure to Sev reduced the number of neurons and the concentration of BDNF in the hippocampus, a brain region important for learning and memory. Additionally, Sev significantly decreased the expression of PKA, p-CREB, BDNF and the p-CREB/CREB ratio. Treatment with bucladesine, a selective PKA agonist, partially reversed the deleterious effects of Sev. In summary, the results indicated that PKA-CREB-BDNF signaling served an important role in the cognitive decline caused by neonatal exposure to Sev.

Poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT) and poly(propylene carbonate) polyurethane (PPCU) were blended by using a twin-screw extruder, and then, the PLA/PBAT/PPCU trinary blends were made into films via the blown film technique. The PLA/PBAT/PPCU blends were characterized by dynamic rheometer and differential scanning calorimetry (DSC). From the analysis of DSC, it indicated that the glass transition temperature (Tg) of PBAT and PPCU was increased and the glass transition temperature (Tg) of PLA was decreased with increasing PPCU content. PPCU could improve miscibility among PLA, PBAT and PPCU. The tests of mechanical showed that the elongation at break of PLA/PBAT/PPCU films decreased from 240 to 226% in the machine direction and from 413 to 353% in the transverse direction. The tensile strength was increased in the machine direction from 40.2 to 46.5 MPa in the machine direction and from 28.5 to 42.8 MPa in the transverse direction. The tear strength was from 1334.7 to 143.6 kN/m in the machine direction and from 137.3 to 147.8 kN/m in the transverse direction. PBAT was a good toughening agent for PLA, and PPCU was a compatibilizer for PBAT and PLA blends.

Polylactide (PLA), methyl methacrylate-butadiene-styrene copolymer (MBS), and poly(propylene carbonate) polyurethane (PPCU) were blended and subjected to blown film process. The rheological, mechanical, morphological, thermal, and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied. Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA. The impact strength of 50/10/40 PLA/MBS/PPCU blend (74.7 kJ/m2) was about 7.5 times higher than that of the neat PLA (10.8 kJ/m2), and the elongation at break of 50/10/40 PLA/MBS/PPCU blend (276.5%) was higher by about 45 times that of PLA (6.2%). The tear strength of PLA/MBS/PPCU films was 20 kN/m higher than that of PLA, and the elongation at break (MD/TD) of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%, whereas that of PLA was only 2.7%/3.0%. POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS. With increasing PPCU content from 5% to 20%, the density of spherulite nucleation increased and the size of crystalline particles decreased continuously, but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30% to 40%. The PLA/MBS/PPCU films exhibited excellent mechanical properties, which expanded the application range of these biodegradable films.

High surface-area manganese oxides catalysts are widely employed in catalytic oxidation of volatile organic compounds (VOCs) because of their high efficiency and good stability. However, template agents are usually introduced to the synthesis process to create the high surface area (>150 m2/g). It is quite expensive and complicated, restricting the widespread applications. Herein, a template-free method was reported here to prepare high surface-area MnO2 catalysts by selectively removing La elements from LaMnO3 perovskites using acid treatment. The obtained MnO2 catalysts possessed excellent catalytic activity in toluene oxidation. Besides, the reserved La elements after acid treatment could be recycled to repeat the preparation process. After three cyclic processes, the catalytic performances were improved gradually, which may provide the possibility for the practical application in VOCs elimination.

Polylactide (PLA) was first toughened with methyl methacrylate-butadiene-styrene (MBS) copolymer. Then the toughened PLA was further blended with diethylene glycol monobutyl ether adipate (DGBEA) using a twin-screw extruder. Finally, the extruded samples were blown using the blown film technique. The PLA/DGBEA/MBS blends were characterized by dynamic rheometer, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC). Rhelological investigation demonstrated that there was a significantly dependence of viscosity on composition. DMA results displayed that the PLA/DGBEA/MBS blends showed a single peak, which suggested that PLA and the shell of MBS be compatible. So, DGBEA could act as a plasticizer and improve the miscibility of PLA/MBS blends. The crystallization morphology, mechanical properties, optical properties, the morphology of the tear-fracture surfaces, and enzymatic degradation of the PLA/DGBEA/MBS films were further studied. The Maltese cross pattern phenomenon weakens and the spherulite size becomes smaller from the observation of the polarized microscope. With an increase of MBS content from 3% to 12%, the tensile strength of the films decreased from 38.2/37.5 MPa (MD/TD) to 25.2/26.4 MPa (MD/TD), however, the elongation at break increased significantly from 72.3/83.1% (MD/TD) to 289.5/286.8% (MD/TD), which indicated the toughening effects of the MBS on PLA. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

Fe3O4 magnetic nano-particles were prepared by a co-precipitation method and were modified using oleic acid. Then, the cross-linked magnetic compsoite microspheres containing a carboxyl group were prepared by using an improved emulsion polymerization with divinylbenzene (DVB) as the cross-linking agent. The composite microspheres comprised the Fe3O4 magnetic nano-particles as cores and the copolymer of styrene and acrylic acid as shells. The morphology and structure of the composite microsphere were characterized by FT-IR, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and so on. The results show that the composite microspheres were well dispersed in emulsion with uniform sizes and carboxyl groups on their surface. They were cross-linked and stable in 1 mol/L of HCl and DMF.