Synthesis and Rapid Polymerizations of Aryl- and Alkyl-bis(azetidine-2,4-dione)s to Polymalonamide Elastomers

Self-polymerization of Meldrum's acid-amine compounds: an effective route to polyamides

Meldrum's acid-amine compounds are effective monomers for the synthesis of linear and hyperbranched polyamides in a short reaction time under mild reaction conditions.

Polymerization of Meldrum's Acid and Diisocyanate: An Effective Approach for Preparation of Reactive Polyamides and Polyurethanes

Meldrum's acid (MA) is utilized as a monomer to polymerize with diisocyanates to result in polyamides, containing MA moieties at polymer chains. This reaction is also employed to prepare isocyanate-terminated polyamide segments which are utilized as a precursor for preparation of MA-containing polyurethanes. Based on the thermolysis reaction of MA groups, followed by ketene dimerization reaction, the reactive polyamides and polyurethanes show self-cross-linkable features. The cross-linked polyurethanes exhibit good film formability, thermal stability, and mechanical properties. A new MA-based polymerization method and a novel synthesis route for preparation of reactive polyamides and polyurethanes are demonstrated.

A strategy for preparing spirobichroman dianhydride from bisphenol A and its resulting polyimide with low dielectric characteristic

The high performance polyimide, SBC-DDM, exhibits a large free volume, leading to outstanding organo-solubility and a low dielectric constant.

An efficient Sn(ii)-catalyzed one-pot synthesis of a 3-substituted azetidine-2,4-dione framework

A novel Sn(ii)-catalyzed tandem cyclization reaction of aromatic aldehydes with ethyl cyanoacetate has been achieved to afford a series of 3-substituted azetidine-2,4-diones in good to excellent yields.

Organic/Metallic nanohybrids based on amphiphilic dumbbell-shaped dendrimers

In this study, we synthesized a series of amphiphilic dumbbell-shaped dendrimers through the addition reactions of a hydrophilic poly(oxyalkylene) with hydrophobic dendrons based on 4-isocyanate-4'-(3,3-dimethyl-2,4-dioxo-azetidine)diphenylmethane with different numbers of branching generations. The addition reaction of azetidine-2,4-diones of dendrons to amines of poly(oxyalkylene) was proceeded by stirring the reactants in dry tetrahydrofuran (THF) under nitrogen at 60 °C. In aqueous media, the dumbbell-shaped dendrimers self-assembled into micelles with their hydrophobic dendrons in the core and their hydrophilic poly(oxyalkylene) segments forming loops in the corona shell. Employing the unique self-assembled micelle structures as templates for subsequent chemical reduction of the Ag(+) ions, we generated new types of organic/metallic [silver nanoparticle (AgNP)] nanohybrid clusters. The long poly(oxyalkylene) loops that extended into the aqueous phase complexed with the Ag(+) ions, providing the suspension with steric stabilization to prevent the AgNPs from collision and flocculation. After reduction, the AgNPs were present in a homogeneous distribution in the round dendrimer micelle-stabilized nanoclusters. The diameter of each AgNP was less than 10 nm; the diameter of each round nanocluster was in the range of 50-200 nm. The encapsulation efficiency of the AgNPs in micelles was about 54-69% for the dumbbell-shaped dendrimer based organic/AgNP nanohybrid.