conviction that polymers are “high-molecular” substances consisting of covalently
bonded chain molecules in a lecture in 1919 [67]. In his teaching, he already had
solidly established the modern concept of polymerization and polymers; lecture
notes of his chemistry students show this convincingly. We show here four pages
from the notes of Adolf Krebser, who took Staudinger’s Organic Chemistry course
in the summer semester of 1919. On the second page, addition polymerization is
introduced and the structure of polyoxymethylene on the third page is self-evident.
The fourth page shows an example of a condensation polymerization (Figs. 2, 3, 4,
and 5).
The nomenclature had not been changed yet: the lecture notes of Max Brunner
(student in the winter semester 1921/22) give a definition of the term polymer that is
almost identical with that of Berzelius (Fig. 6).
In 1920, there followed a landmark paper [68] entitled “On polymerization” in
which Staudinger explains his views on polymerization and attempts to separate
polymerization from similar processes, such as dimerizations where the dimer is not
able to react analogously to the monomer. He also introduced the, now common,
chain formulae for polyoxymethylene, polystyrene, and polyisoprene (caoutchouc) –
but not without crediting Pickles [66] for inventing the notation with the example
of polyisoprene – and the polymeric anhydrides of malonic acid and adipic acid.
These were still largely conjectures, but Hermann Staudinger and Jakob Fritschi
[69] provided the first convincing experimental proof with the observation that
caoutchouc and its saturated derivative (“hydrogenated rubber”) exhibit the same
“colloidal” behavior, even though caoutchouc has a large number of electron-rich
double bonds (before believed to be the cause of the colloidal behavior) and the
hydrogenated alkane is entirely devoid of them. In addition, they also emphasized
the fact that polymolecularity of such high molecular weight substances was
unavoidable.
After 14 years at ETH, Herrmann Staudinger left Zurich in 1926 and assumed a
position at the University of Freiburg (Germany), where he continued and amplified
his work on macromolecules (Fig. 7).
Staudinger relentlessly championed the molecular, or primary valence,
viewpoint in the years that followed [1, 70]. His research group systematically
created a number of new polymer classes and he was slowly joined in his views by a
larger and larger fraction of scientists. Some exceptional synthetic chemists
supported his concepts (e.g., Wallace Hume Carothers [71]) and physical chemists
and physicists joined ranks with him (e.g., Kurt Heinrich Meyer [72], Herman
Francis Mark [73], Werner Kuhn [74], and Rudolf Signer [75]) although their
relationships with Staudinger were more often strained than not. Staudinger was a
man of strong character and not always willing to compromise.
In the mid-1930s the battle had largely been won. Only a few pockets of science
continued to harbor colloidal concepts for chain molecules (e.g., biology), but these
areas had also adopted “Staudinger’s” viewpoint by 1940.
Why Was the Macromolecular Hypothesis Such a Big Deal?
71
bonded chain molecules in a lecture in 1919 [67]. In his teaching, he already had
solidly established the modern concept of polymerization and polymers; lecture
notes of his chemistry students show this convincingly. We show here four pages
from the notes of Adolf Krebser, who took Staudinger’s Organic Chemistry course
in the summer semester of 1919. On the second page, addition polymerization is
introduced and the structure of polyoxymethylene on the third page is self-evident.
The fourth page shows an example of a condensation polymerization (Figs. 2, 3, 4,
and 5).
The nomenclature had not been changed yet: the lecture notes of Max Brunner
(student in the winter semester 1921/22) give a definition of the term polymer that is
almost identical with that of Berzelius (Fig. 6).
In 1920, there followed a landmark paper [68] entitled “On polymerization” in
which Staudinger explains his views on polymerization and attempts to separate
polymerization from similar processes, such as dimerizations where the dimer is not
able to react analogously to the monomer. He also introduced the, now common,
chain formulae for polyoxymethylene, polystyrene, and polyisoprene (caoutchouc) –
but not without crediting Pickles [66] for inventing the notation with the example
of polyisoprene – and the polymeric anhydrides of malonic acid and adipic acid.
These were still largely conjectures, but Hermann Staudinger and Jakob Fritschi
[69] provided the first convincing experimental proof with the observation that
caoutchouc and its saturated derivative (“hydrogenated rubber”) exhibit the same
“colloidal” behavior, even though caoutchouc has a large number of electron-rich
double bonds (before believed to be the cause of the colloidal behavior) and the
hydrogenated alkane is entirely devoid of them. In addition, they also emphasized
the fact that polymolecularity of such high molecular weight substances was
unavoidable.
After 14 years at ETH, Herrmann Staudinger left Zurich in 1926 and assumed a
position at the University of Freiburg (Germany), where he continued and amplified
his work on macromolecules (Fig. 7).
Staudinger relentlessly championed the molecular, or primary valence,
viewpoint in the years that followed [1, 70]. His research group systematically
created a number of new polymer classes and he was slowly joined in his views by a
larger and larger fraction of scientists. Some exceptional synthetic chemists
supported his concepts (e.g., Wallace Hume Carothers [71]) and physical chemists
and physicists joined ranks with him (e.g., Kurt Heinrich Meyer [72], Herman
Francis Mark [73], Werner Kuhn [74], and Rudolf Signer [75]) although their
relationships with Staudinger were more often strained than not. Staudinger was a
man of strong character and not always willing to compromise.
In the mid-1930s the battle had largely been won. Only a few pockets of science
continued to harbor colloidal concepts for chain molecules (e.g., biology), but these
areas had also adopted “Staudinger’s” viewpoint by 1940.
Why Was the Macromolecular Hypothesis Such a Big Deal?
71