New for old: A novel catalytic combustion method to synthesize multiwalled carbon nanotubes (MWNTs, see SEM image) in situ in high yields from polypropylene as the carbon source in the presence of an organic‐modified clay and a supported nickel catalyst is reported. The method allows new high‐value MWNTs to be created from used polypropylene in an energy‐saving and environmentally friendly process.
Aus alt mach neu: Eine neuartige Methode zur katalytischen Verbrennung von Polypropylen liefert hohe Ausbeuten an mehrwandigen Kohlenstoffnanoröhren (MWNTs, siehe Rasterelektronenmikroskopie‐Bild) in Gegenwart eines mit organischen Gruppen modifizierten Tones und eines immobilisierten Nickelkatalysators. Der umweltverträgliche Prozess wandelt gebrauchtes Polypropylen in hochwertige MWNTs um.
A simple novel method for preparing multiwalled carbon nanotubes/montmorillonite (MWNTs/MMT) hybrids has been established through mixing pristine MWNTs in MMT aqueous dispersion. The principle of this method is based on the formation of stable dispersion containing both MWNTs and MMT in water, which results from strong interaction between MWNTs and MMT platelets. Sedimentation experiments, measurements of ζ potential, and Raman spectra have been used to confirm the presence of strong interaction between MWNTs and MMT sheets. The morphology observation for the dried MWNTs/MMT hybrids shows that the obtained hybrids are homogeneous, in which MWNTs exist as the state of single nanotubes that are absorbed on the surface and edge of MMT sheets. In addition, poly(ethylene oxide) (PEO) nanocomposites containing both MWNTs and MMTs are prepared by using this method. An obvious synergistic effect of MMT sheets and MWNTs in improving mechanical properties of PEO matrix has been observed.
In the treatment of breast cancer, decisions on adjuvant treatment reflect individual patient characteristics like age and comorbidity. This study assessed the association between adherence to guidelines for adjuvant treatment and survival while taking into account age at diagnosis and comorbidities. We collected the Charlson comorbidity index at baseline for 2179 women treated for primary breast cancer from 1992 to 2008 who participated in a German retrospective multicenter cohort study. We assessed subsequent adjuvant therapy guideline adherence and survival in relation to baseline comorbidities. Guidelines for adjuvant chemotherapy and radiotherapy were more often violated in patients with higher Charlson score. Patients with higher Charlson scores received chemotherapy and radiotherapy less often and had higher rates of mastectomy. Irrespective of comorbidity (Charlson score 0, 1-2, ≥3), patients with 100% guideline-adherent adjuvant treatment showed better overall and disease-free survival (DFS) compared to patients with guideline violations (GVs). Controlling for age, comorbidity and tumor characteristics, the hazard ratio for at least one GV was 1.65 (95% confidence interval [CI]: 1.33-2.07) for overall survival and 1.84 (95% CI: 1.53-2.22) for DFS. Guideline-adherent treatment was significantly less frequent in comorbid patients, although guideline adherence was strongly associated with improved survival, irrespective of severity, and number of comorbid diseases.
ABSTRACT:The degradation and flame retardancy of polypropylene/organically modified montmorillonite (PP/ OMMT) nanocomposite were studied by means of gas chromatography-mass spectrometry and cone calorimeter. The catalysis of hydrogen proton containing montmorillonite (H-MMT) derived from thermal decomposition of (alkyl) ammonium in the OMMT on degradation of PP strongly influence carbonization behavior of PP and then flame retardancy. Brønsted acid sites on the H-MMT could catalyze degradation reaction of PP via cationic mechanism, which leads to the formation of char during combustion of PP via hydride transfer reaction. A continuous carbonaceous MMT-rich char on the surface of the burned residues, which work as a protective barrier to heat and mass transfer, results from the homogeneous dispersion of OMMT in the PP matrix and appropriate char produced.
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