Poly(enonsulfides) from the addition of aromatic dithiols to aromatic dipropynones

Abstract

SynopsisNovel poly(enonsu1fides) were prepared with inherent viscosities as high as 1.35 dL/g by nucleophilic addition of various aromatic dithiols to 1,l'-(1,3-or 1,4-phenylene)bis(3-phenyl-2-propyn-1-one) in m-cresol at 25-40°C. A tough clear yellow film with a tensile strength of 11,300 psi and a tensile modulus of 466,000 psi at 25°C was cast from a chloroform solution of the polymer prepared from 1,3-dithiobenzene and l,l'-(1,4-phenylene)bis(3-phenyl-2-propy-l-one). The poly(enonsu1fides) exhibited Tg's as high as 180°C and weight losses of approximately 10% at 331°C in air. The synthesis and characterization of several poly(enonsu1fides) are discussed.

Click Nucleophilic Conjugate Additions to Activated Alkynes: Exploring Thiol-yne, Amino-yne, and Hydroxyl-yne Reactions from (Bio)Organic to Polymer Chemistry

“…Unfortunately, these aromatic thiol-yne polymers were difficult to fully characterize as a result of their limited solubility, however, the polymers could be retrieved in high yields (>90%) by a simple precipitation procedure in methanol (Scheme 11). 136 Poor overall solubility made typical characterization techniques challenging, nevertheless, the aromatic backbones resulted in thermally robust polymers as evidenced by a high decomposition temperature (T d,10% ≥ 330 °C) with glass transition temperatures (T g ) above 100 °C that were also dependent on regiochemistry, where an increasing quantity of 1,4-aryl substitution over 1,3-substitution in the polymer backbone led to a ∼20 °C increase in the T g .…”

“…As a consequence of their exceptional reactivity, ynones were the first Michael acceptors to be polymerized with dithiols in a thiol-yne polyaddition. − Bass and co-workers synthesized a series of disubstituted aryl internal ynones from the addition of lithium phenylacetylide to aryl dialdehydes . These diynone species were then reacted with dithiophenols in the presence of methylmorpholine to furnish unsaturated step-growth polymers with pendant phenyl groups.…”

Click Step-Growth Polymerization and E/Z Stereochemistry Using Nucleophilic Thiol–yne/–ene Reactions: Applying Old Concepts for Practical Sustainable (Bio)Materials

“…Notably, work in the late 1980s reported several base-catalyzed thiol–yne polymerizations using thiophenols and aromatic ynones, although their poor solubility generally precluded in-depth characterization. − In 2010, Tang and co-workers also reported an amine-catalyzed thiol–yne polymerization of bisthiophenols and aromatic dipropiolates to yield unsaturated step-growth polymers with moderate molar mass ( M W = 30 kDa) and high Z -content (up to 80%) . While these studies had an exclusive focus on aromatic polymers, we anticipated that the aliphatic polymers would have superior processability, mechanical performance, and degradability, all of which are important metrics to consider in the context of sustainable polymers.…”

Activated Internal Alkyne‐Based Polymerization†

“…A precursive attempt to prepare poly(enonsulfide)s with good mechanical and thermal performance by nucleophilic addition polymerization of activated dipropynones with aromatic dithiols was reported by Bass and coworkers in 1987 (Scheme 3a). [ 42 ] Interestingly, the stereoregularity of polymers could be fine‐tuned via the reaction solvent and base catalyst. Coincidentally, Dix and coworkers explored a similar polyaddition reaction between dithiothreitol and bis(acetylene ketone) in the presence of triethylamine, and a poly(enone‐sulfide) with 60% Z ‐isomer and moderate molecular weight was yielded, which might be used as a curing system for paint, coating or adhesive.…”