ISSN:
0570-0833
Keywords:
Addition polymerization
;
Polymerization
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The polymerizability of compounds such as 1,l-disubstituted ethylenes, aldehydes, ketones, isocyanates, and five- and six-membered ring compounds is determined largely by thermodynamic considerations. The transition from non-polymerizability to polymerizability, correspondlng to a change in the sign of ΔG, is often quite sharp. Factors which generally make the free energy of polymerization more negative, and which therefore favor polymerization, are low temperature, high pressure, and high monomer concentration. Additional driving force is sometimes available if the monomer is in the supercooled (glassy) state rather than the crystalline state, or if the polymer crystallizes on formation. Alkyl substituents have an unfavorable effect on polymerizability; halogen substituents have a favorable effect. Many monomers which do not homopolymerize for thermodynamic reasons will copolymerize with a second monomer to the extent of forming copolymers containing 50 or even 66 mol per cent of the first monomer.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/anie.197304871
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