ISSN:
1572-8935
Keywords:
Solvent effects
;
Promoter effects
;
Monomer reactivity ratios
;
Hexamethylcyclotrisiloxane (D3)
;
Hexaphenylcyclotrisiloxane (P3)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The solvent and promoter effects on the monomer reactivity ratios, r1 and r2, for the living copolymerization of hexamethylcyclotrisiloxane (D3) and hexaphenylcyclotrisiloxane (P3) in the case of relatively high [monomer]0/[initiator]0 ratio and low phenyl content (less than 50%) are reported. The amount of promoter DMSO had significant effects on the reactivity ratios, r1 and r2, in toluene as well as in THF with different trend. The values of r1 decreased while r2 increased with the decreasing of the amount of DMSO in toluene. Both r1 and r2 increased with a decrease of the amount of DMSO in THF. For copolymerizations in mixed solvents, r1 was less sensitive to the change of THF portion than r2 in the presence of 0.5 wt% of promoter DMSO. Eventually, r1 became equal to r2 in 100 % THF (r1 = r2 = 0.19). However, without DMSO, r1 became more sensitive to the change in THF concentration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01494256
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