Preparation of high performance PP/ reduced graphene oxide nanocomposites through a combined in situ polymerization and masterbatch method

Despite the great potential of graphene as a nanofiller, achieving homogeneous dispersion remains the key challenge for effectively reinforcing polyolefin (such as polyethylene (PE) and polypropylene (PP)) nanocomposites. Therefore, in this research, we report a facile combined in situ polymerization and masterbatch method for fabricating PP/reduced graphene oxide (rGO) nanocomposites. In the polymerization stage, the synthesized catalyst exhibited a very high activity toward propylene polymerization, while the resultant PP/rGO with a very high isotactic index (I.I. = 99.3), broad molecular weight distribution (Mw/Mn = 14.9), and thermal stability was produced. After meltblending with commercial PP, a significantly increased modulus along with no observable change in tensile strength and elongation-at-break were achieved via the addition of a very small amount of rGO; these properties resulted from the suitable dispersion and good interface adhesion of the graphene sheet and PP matrix. Thus, this work provides a method for production of high performance PP

Fabrication and Characterization of Collagen-Immobilized Porous PHBV/HA Nanocomposite Scaffolds for Bone Tissue Engineering

The porous composite scaffolds (PHBV/HA) consisting of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and hydroxyapatite (HA) were fabricated using a hot-press machine and salt-leaching. Collagen (type I) was then immobilized on the surface of the porous PHBV/HA composite scaffolds to improve tissue compatibility. The structure and morphology of the collagen-immobilized composite scaffolds (PHBV/HA/Col) were investigated using a scanning electron microscope (SEM), Fourier transform infrared (FTIR), and electron spectroscopy for chemical analysis (ESCA). The potential of the porous PHBV/HA/Col composite scaffolds for use as a bone scaffold was assessed by an experiment with osteoblast cells (MC3T3-E1) in terms of cell adhesion, proliferation, and differentiation. The results showed that the PHBV/HA/Col composite scaffolds possess better cell adhesion and significantly higher proliferation and differentiation than the PHBV/HA composite scaffolds and the PHBV scaffolds. These results suggest that the PHBV/HA/Col composite scaffolds have a high potential for use in the field of bone regeneration and tissue engineeringclose2

Allogeneic Stem Cell Transplantation for Patients with Advanced Hematological Malignancies: Comparison of Fludarabine-based Reduced Intensity Conditioning versus Myeloablative Conditioning

We compared the outcomes of allogeneic hematopoietic stem cell transplantation using reduced intensity and myeloablative conditioning for the treatment of patients with advanced hematological malignancies. A total of 75 adult patients received transplants from human leukocyte antigen-matched donors, coupled with either reduced intensity (n=40; fludarabine/melphalan, 28; fludarabine/cyclophosphamide, 12) or myeloablative conditioning (n=35, busufan/cyclophosphamide). The patients receiving reduced intensity conditioning were elderly, or exhibited contraindications for myeloablative conditioning. Neutrophil and platelet engraftment occurred more rapidly in the reduced intensity group (median, 9 days vs. 18 days in the myeloablative group, p<0.0001; median 12 days vs. 22 days in the myeloablative group, p=0.0001, respectively). Acute graft-versus-host disease (≥grade II) occurred at comparable frequencies in both groups, while the incidence of hepatic veno-occlusive disease was lower in the reduced intensity group (3% vs. 20% in the myeloablative group, p=0.02). The overall 1-yr survival rates of the reduced intensity and myeloablative group patients were 44% and 15%, respectively (p=0.16). The results of present study indicate that patients with advanced hematological malignancies, even the elderly and those with major organ dysfunctions, might benefit from reduced intensity transplantation

Preparation of Isotactic Polypropylene/Exfoliated MoS2 Nanocomposites via In Situ Intercalative Polymerization

In this research, a Ziegler–Natta catalyst intercalated MoS2 was synthesized through the intercalation of a Grignard reagent into MoS2 galleries, followed by the anchoring of TiCl4. During propylene polymerization, the intercalated MoS2 exfoliated in situ to form PP/exfoliated MoS2 (EMoS2) nanocomposites. The isotactic index values of the resultant PP/EMoS2 nanocomposites were as high as 99%, varying from 98.1% to 99.0%. It was found that the incorporation of the EMoS2 significantly improved the thermal stability and mechanical properties (tensile strength, modulus, and elongation at break) of PP. After introduction of EMoS2, the maximum increases in Td5% and Tdmax were 36.9 and 9.7 °C, respectively, relative to neat PP. After blending with commercial PP, the resultant nanocomposites increase in tensile strength and modulus up to 11.4% and 61.2% after 0.52 wt % EMoS2 loading. Thus, this work provides a new way to produce high-performance PP

Performance Evaluation of Red Clay Binder with Epoxy Emulsion for Autonomous Rammed Earth Construction

&nbsp;Existing rammed earth construction methods have disadvantages such as increased initial costs for manufacturing the large formwork and increased labor costs owing to the labor-intensive construction techniques involved. To address the limitations of the existing rammed earth construction methods, an autonomous rammed earth construction method was introduced herein. When constructing an autonomous rammed-earth construction method, an alternative means of assuring the performance at the initial age of the binder in terms of materials is needed. In this study, in order to satisfy the performance of the red clay binder, epoxy emulsion was added to analyze the compressive strength, water loosening, shrinkage, rate of mass change, and microstructure in the range of the initial age. As a result of the analysis, the applicability of the epoxy emulsion was confirmed as a new additive for application to an autonomous rammed-earth construction method

Synthesis, Film Fabrication, and Optical Properties of Polymers Containing Metal Cation Complex Type D-pi-A Chromophore

Donor-pi-acceptor (D-pi-A) type chromophore-based polymers were newly synthesized. These polymers exhibited absorption peak due to intramolecular charge transfer (ICT) in a visible range as well as absorption peak due to carbonyl group in both solution and film state by measuring UV visible spectra. The addition of Eu(3+) ion into the polymers induced red-shift in absorption due to ICT and the color changes from yellow to red in the solution and film were observed by naked eyes. The contents of crosslinking agent influenced the features and solubility of the polymers. In addition, the contents of crosslinking agent and the Eu(3+) ion addition improved film-forming ability.1