Silica-Like Malleable Materials from Permanent Organic Networks
Science, 2011 · paper · Materials
Designs epoxy networks that rearrange their cross-links by exchange reactions without breaking down into separate chains. They are insoluble yet processable, and their viscosity changes gradually with temperature in an Arrhenius-like way, unlike typical polymers near the glass transition.
2 findings
Substance For the 0.1 mol% sample, the text says the linear expansion coefficient "remains constant from 50° to 250°C". The same paragraph says a glass transition "is visible at lower temperature for both samples", and Tg is "~80°C" (p. 2), which lies inside that range.
- p. 3 Main text, column 2, dilatometry paragraph
remains constant from 50° to 250°C
- p. 3 Main text, column 2, same paragraph
which is visible at lower temperature for both samples with and without a catalyst
- p. 2 Main text, column 3
glass transition at ~80°C
- p. 3 Fig. 4A, 0.1%-1K/min trace
0.1%-1K/min
Only the authors can say what is right here.
Judge's note: The p. 3 text and the Fig. 4A image show the 0.1%-1K/min (pink) trace with a low slope near 50–90°C and a steeper slope above about 100°C, consistent with a glass transition near the stated Tg of ~80°C. A coefficient that is constant from 50°C contradicts both the figure and the next sentences. The lower bound of the range is probably meant to lie above Tg. Only the authors can give the intended range.
Second check: another model agreed
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Reference or label Activation energies are given in the wrong unit: "activation energy of ~80 kJ/mol K" (p. 2) and "activation energy of ~88 kJ/mol K" (p. 3). Both should be kJ/mol.
- p. 2 Main text, column 2, discussion of Fig. 2B inset
activation energy of ~80 kJ/mol K
- p. 3 Results, elongational creep
with activation energy of ~88 kJ/mol K
- p. 3 column 1, creep experiment
activation energy of ~88 kJ/mol K
Judge's note: The page images show 'kJ/mol K' in both places: p. 2, column 2, Fig. 2B inset discussion, and p. 3, column 1, creep viscosity. An Arrhenius activation energy is an energy per mole, so this is a wrong unit (S2). The numbers themselves are not affected.
Second check: another model agreed
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2 minor (typos and the like; most checked by the judge only)
Wording The text says the glass transition is visible "for both samples with and without a catalyst", but the two Fig. 4A samples contain "0.1 mol % (purple) and 5 mol % Zn(acac)2 (black)".
- p. 3 Discussion, dilatometry paragraph
for both samples with and without a catalyst
- p. 3 Fig. 4A caption
with 0.1 mol % (purple) and 5 mol % Zn(acac)2 (black)
Judge's note: The p. 3 caption and text show that both dilatometry samples contain Zn(acac)2. The earlier sentence calls the low-loading one 'the sample with 0.1 mol% Zn(acac)2 catalyst'. 'Without a catalyst' is loose shorthand for a negligible loading.
Second check: another model agreed
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Typo Misspelling on p. 2: "a study of transterification kinetics of model molecules" should read 'transesterification'.
- p. 2 Main text, column 2, first paragraph
a study of transterification kinetics of model
- p. 2 column 1
transterification kinetics
Judge's note: The page 2 image, column 2, shows 'transterification'. Everywhere else the paper spells it 'transesterification'.
Second check: none (judge only)