In the synthesis of linear step-growth polymers molecular weight control is accomplished through the addition of a controlled amount of monomer carrying the functional group B in excess (B-B or H-B types). The Carothers equation is used to calculate average chain lengths. This paper extends the analysis of chain lengths to include the effect of monofunctional monomers carrying the limiting group A (H-A), allowing the systematic analysis of complex systems containing both bifunctional and monofunctional species of any type (A-A, B-B, H-B and H-A). This refinement is particularly relevant for the synthesis of oligomers from systems with complex feed composition.
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Generalization of the Carothers equation for linear step growth polymers.
Sci Rep
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Department of Mining-Metallurgy Engineering and Materials Science, Faculty of Engineering, POLYMAT, University of the Basque Country (UPV/EHU), Plaza Ingeniero Torres Quevedo 1, Bilbao, Spain.
In the synthesis of linear step-growth polymers molecular weight control is accomplished through the addition of a controlled amount of monomer carrying the functional group B in excess (B-B or H-B types). The Carothers equation is used to calculate average chain lengths. This paper extends the analysis of chain lengths to include the effect of monofunctional monomers carrying the limiting group A (H-A), allowing the systematic analysis of complex systems containing both bifunctional and monofunctional species of any type (A-A, B-B, H-B and H-A).
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J Am Chem Soc
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Molecular Engineering & Sciences Institute, University of Washington, Seattle, Washington 98195, United States.
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Adv Mater
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Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA.
The molecular weight (MW) of PBnDT-FTAZ can be precisely controlled by adjusting the stoichiometric ratio of the two monomers, following the Carothers equation. The study of a set of PBnDT-FTAZ polymers with different MWs reveals that the MW significantly influences the morphology and structural order of PBnDTFTAZ in its bulk heterojunction solar cells, with the highest efficiency (over 7%) achieved with the use of a MW of 40 000 g mol(-1) .
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