Polyamide nanofilms synthesized via controlled interfacial polymerization on a “jelly” surface

A thermal-sensitive “jelly” was used to control the diffusion of a diamine monomer for synthesizing polyamide free-standing nanofilms with an adjustable thickness of 5–35 nm.

Synthesis and properties of the novel polyimides containing cyano and biphenyl moieties

A series of cyano-functionalized polyimides (CN-PIs) were prepared and derived from a novel diamine monomer having cyano and biphenyl groups. Meanwhile, another series of PIs without cyano groups (H-PIs) were prepared as counterparts for comparison purposes. Both series of PIs exhibited good solvent resistance, good thermal stability, remarkable film-forming ability, and excellent tensile properties. The Tg values of CN-PIs were 260–330°C, which were 10–17°C higher than the corresponding –CN free H-PIs. The CN-PIs exhibited no obvious decomposition below 470°C, and their 5% weight loss temperatures were above 568°C under nitrogen atmosphere. All the CN-PI films had high tensile strength and Young’s moduli, which were related to their rigid backbones and strong interactions between molecular chains. Due to their higher molar polarization, CN-PIs expressed the higher dielectric constants (3.29–3.69 at 1 MHz) in comparison with the corresponding H-PIs. CN-PIs exhibited the improved transparency, and both CN-PIs and H-PIs had better transparency than commercial Kapton® film. Introducing –CN groups could have an effect on the coefficient of thermal expansion and peel strength of the PIs. The peel strength of the PI, which was derived from cyano-functionalized diamine monomer and 4,4′-oxydiphthalic anhydride, could even reach 1.10 N mm-1, suggesting its strong interaction to copper matrix and potential use in flexible circuit board.

Synthesis of aromatic, soluble, and thermally stable polyamides derived from new diamine containing unsymmetrical phenolphthalein and imidazole pendent group

A novel diamine monomer containing unsymmetrical phenolphthalein and triaryl imidazole pendant group, 3,3-bis(4-(4-amino-2-(4,5-diphenyl-1H-imidazol-2-yl)phenoxy)phenyl)isobenzofuran-1(3H)-one (BADPPI), was successfully prepared in three steps. The novel diamine monomer BADPPI was directly polymerized with commercially available diacids, such as terephthalic acid, isophthalic acid, pyridine-2,6-dicarboxylic acid, and adipic acid, to obtain corresponding polyamides (PAs). The resulting novel aromatic PAs were obtained in high yields and moderate inherent viscosities in the range of 0.52–0.57 dL g−1 and exhibited excellent solubility in aprotic polar solvents, such as N,N-dimethylacetamide , N-methyl-2-pyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, meta cresol, and pyridine. PAs showed high glass-transition temperatures between 191°C and 277°C. Thermogravimetric analysis of the PAs indicated a 10% weight loss ( T10%) in the temperature range of 382–473°C and char yields at 600°C under nitrogen atmosphere in the range of 56–70% depending on the diacids monomer used for the PAs preparation.