Influence of moieties on morphology, thermal, and dielectric properties in polyamide‐polyhedral oligomeric silsequioxanes nanocomposites

Abstract

A series of new hexafluoroisopropylidene, isopropylidene, carbonyl, and ether moieties substituted polyamides have been prepared from aromatic diamines and various moieties substituted aromatic dianhydrides. The synthesized polyamides were readily soluble in polar solvents such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. These polyamides exhibited good thermal stability and high char yields. The chemical and physical properties of the newly prepared polyamide‐polyhedral oligomeric silsequioxanes (PA‐POSS) were compared in terms of their chemical structures and thermal properties. The morphological properties of the polymeric nanocomposites depend both on their chemical structure of dianhydride and the aggregation of POSS were investigated by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Polyamides with bulky POSS and fluoro groups can effectively decrease dielectric constants. The dielectric constants of PA‐POSS were found to be decreased from 3.75 to 3.29 by changing the substitution. These polyamides showed good thermal stability up to 353 °C for a 10 % weight loss. The fluorinated polyamides have relatively higher thermal stability than the polyamides without halogen because of high bond energy of CF bond. The fiuorinated groups in the polymer backbone have played an important role in the improvement of dielectric performance of polymers. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Effect of POSS and chain extender on tensile and fracture properties of neat and short glass fiber reinforced polyamide 6 composites

“…Though the smaller in size these additives, the greater the contribution of interfacial interactions to the material properties of composite material. Thus significant enhancement of mechanical, thermal and physicochemical properties can be acquired by using nano-fillers of different sizes and aspect ratios, such as layered silicates, carbon nanotubes and polyhedral oligomeric silsequioxanes (POSS), into various polymeric matrices [15][16][17].…”

Influence of Polymethylsilsesquioxane Content to the Thermal Stability of Meta-Aramid Fiber Insulation Paper

“…The modified material has the dual advantages of inorganic nanomaterials and organic polymer materials. POSS can improve the thermal stability [4,6,9,10,11,12], mechanical properties [4,6,12,13,14], hydrophobicity [15,16,17], flame retardancy [18,19,20], and dielectric properties [21,22,23] of the polymer at the molecular level; this modification method has been widely studied by researchers.…”

Incorporation of COF‐LZU‐1 into the terpolyimide matrix to obtain COF‐LZU‐1/terpolyimide composites with ultra‐low dielectric constant

“…So, the researchers have applied different post‐modification methods to reduce it to a convenient scale. Several methods such as incorporation of porous material into the polymer matrix , thermal degradation of labile graft or block chains in the polyimides , introduction of bulk fluorinated substituents into the polymer backbone , and so forth. were applied to reduce dielectric constant.…”