The influence of molecular weight distribution on the optimal thermal treatment of poly(3-hexythiophene) based bulk heterojunction photovoltaic cells

2006 ◽  
Vol 36 (3) ◽  
pp. 295-300 ◽  
Author(s):  
R. C. Hiorns ◽  
R. de Bettignies ◽  
J. Leroy ◽  
S. Bailly ◽  
M. Firon ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Treatment ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Bulk Heterojunction ◽  
Photovoltaic Cells

scholarly journals Ring-Opening Polymerisation ofrac-Lactide Using a Calix[4]arene-Based Titanium (IV) Complex

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Marco Frediani ◽  
David Sémeril ◽  
Dominique Matt ◽  
Luca Rosi ◽  
Piero Frediani ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Treatment ◽  
Microwave Irradiation ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Ring Opening ◽  
The Other ◽  
Maldi Tof ◽  
Other Hand ◽  
First Time

cone-25,27-Dipropyloxy-26,28-dioxo-calix[4]arene titanium (IV) dichloride(1)has been assessed in the ring-opening polymerisation ofrac-lactide (L,D-LA). The polymers formed (PLDA) turned out to display an isotactic stereoblock microstructure (determined by NMR) despite the fact that the catalyst hasC2vsymmetry. Two techniques were applied for initiating the polymerisation reaction, microwave irradiation, and conventional thermal treatment. The polymers obtained were all characterised by NMR, IR, HPLC-SEC, DSC, and MALDI-TOF analysis. The use of microwave irradiation, applied for the first time to calixarene-based catalysts in the presence of therac-lactide monomer, increased the polymerisation rate compared with that obtained by the other method. On the other hand, standard thermal treatment enabled a slightly better control than microwave irradiation over the molecular weight and molecular weight distribution of the polylactides formed.

Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.)

2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe
Keyword(s):  
Molecular Weight ◽  
Protein Content ◽  
Ammonium Sulfate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Protease Activity ◽  
Protein Concentration ◽  
Temperature Stability ◽  
Partial Purification ◽  
Ammonium Sulfate Precipitation

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 

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