Modification of polycarbosilane by polyborazine as a precursor for oxygen-free SiC fibersElectronic supplementary information (ESI) available: DSC thermograms; molecular weight distributions; chromatograms of hydrogen evolution; 29Si NMR spectra. See http://www.rsc.org/suppdata/jm/b3/b303573e/

2003 ◽  
Vol 13 (8) ◽  
pp. 1914 ◽  
Author(s):  
Feng Cao ◽  
Xiao-dong Li ◽  
Jae-ho Ryu ◽  
Dong-pyo Kim
Keyword(s):  
Molecular Weight ◽  
Hydrogen Evolution ◽  
Nmr Spectra ◽  
Supplementary Information ◽  
29Si Nmr ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
29Si Nmr Spectra ◽  
Dsc Thermograms

17O, 13C, and 29Si NMR spectra of some acyloxy- and diacetoxysilanes and acetoxygermanes

1986 ◽  
Vol 51 (11) ◽  
pp. 2582-2589 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
Karel Handlíř ◽  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Periodic System ◽  
Time Scale ◽  
Nmr Spectra ◽  
Group Element ◽  
29Si Nmr ◽  
Carboxyl Group ◽  
29Si Nmr Spectra ◽  
Oxygen Atoms

The 17O, 13C, and 29Si NMR spectra of (CH3)3SiOC(O)R, CH3(XCH2)Si(OC(O)CH3)2, and R3GeOC(O)CH3 compounds are reported. In the 17O NMR spectra at 350 K the only signal is observed with the two latter series, but two well-resolved signals are displayed with the (CH3)3SiOC(O)R compounds. The equivalence of both oxygen atoms in carboxyl group on the NMR time scale is discussed from the viewpoint of a possible coordination of the oxygen atoms to the IVB group element of the periodic system.

The alteration of molecular weight distributions of polymers by ultrasonic energy

1968 ◽  
Vol 25 (1) ◽  
pp. 145-153 ◽  
Author(s):  
George J. Heymach ◽  
Donald E. Jost
Keyword(s):  
Molecular Weight ◽  
Ultrasonic Energy ◽  
Molecular Weight Distributions ◽  
Weight Distributions

Supramolecular Association of Acid-Terminated Poly(dimethylsiloxane)s. 2. Molecular Weight Distributions

2000 ◽  
Vol 33 (22) ◽  
pp. 8479-8487 ◽  
Author(s):  
S. Abed ◽  
S. Boileau ◽  
L. Bouteiller
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions

The Use of Novel F-RAFT Agents in High Temperature and High Pressure Ethene Polymerization: Can Control be Achieved?

2007 ◽  
Vol 60 (10) ◽  
pp. 788 ◽  
Author(s):  
Markus Busch ◽  
Marion Roth ◽  
Martina H. Stenzel ◽  
Thomas P. Davis ◽  
Christopher Barner-Kowollik
Keyword(s):  
Molecular Weight ◽  
High Pressure ◽  
High Temperature ◽  
Degree Of Polymerization ◽  
Molecular Weight Distributions ◽  
High Pressure High Temperature ◽  
Reversible Addition ◽  
Weight Distributions ◽  
Raft Agent ◽  
Initial Results

Simulations are employed to establish the feasibility of achieving controlled/living ethene polymerizations. Such simulations indicate that reversible addition–fragmentation chain transfer (RAFT) agents carrying a fluorine Z group may be suitable to establish control in high-pressure high-temperature ethene polymerizations. Based on these simulations, specific fluorine (F-RAFT) agents have been designed and tested. The initial results are promising and indicate that it may indeed be possible to achieve molecular weight distributions with a polydispersity being significantly lower than that observed in the conventional free radical process. In our initial trials presented here (using the F-RAFT agent isopropylfluorodithioformate), a correlation between the degree of polymerization and conversion can indeed be observed. Both the lowered polydispersity and the linear correlation between molecular weight and conversion indicate that control may in principle be possible.

Determination of molecular weight distributions of polymers by desorption chemical ionization mass spectrometry

1992 ◽  
Vol 64 (17) ◽  
pp. 1879-1884 ◽  
Author(s):  
Marco. Vincenti ◽  
Ezio. Pelizzetti ◽  
Alessandro. Guarini ◽  
Silvestro. Costanzi
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Desorption Chemical Ionization ◽  
Molecular Weight Distributions ◽  
Weight Distributions

Environmentally Benign Adhesive Synthesized by Dispersion Copolymerization of Styrene and Butyl Acrylate

2006 ◽  
Vol 11-12 ◽  
pp. 757-760
Author(s):  
Jun Ying Zhang ◽  
Peng Dou
Keyword(s):  
Molecular Weight ◽  
Butyl Acrylate ◽  
Monomer Concentration ◽  
Environmentally Benign ◽  
Functional Monomer ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Stabilizer Concentration ◽  
Ethanol Medium ◽  
Weight Distributions

Environmentally benign adhesive was synthesized by dispersion copolymerization of styrene(St) and butyl acrylate (BA) in an ethanol medium with benzoyl peroxide (BPO) as the initiator and poly(vinylpyrrolidone) as the stabilizer in the presence of acrylic acid(AA) as the functional monomer. The effect of the concentration of stabilizer, initiator and functional monomer on the conversions, molecular weights and molecular weight distributions was investigated. The results show that the conversions almost keep invariable with the increasing of stabilizer concentration, but the molecular weights increase and molecular weight distributions decrease. Conversions increase with the increasing of initiator concentration, but the molecular weights and molecular weight distributions decrease. However with the increasing of functional monomer concentration, conversions and molecular weight distributions increase but the molecular weights decrease.

Molecular Weight Distributions in Polycondensation

1971 ◽  
Vol 5 (4) ◽  
pp. 679-685 ◽  
Author(s):  
J. G. Watterson ◽  
J. W. Stafford
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions
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