Synthesis and properties of silica–polyimide hybrid films derived from colloidal silica particles and polyamic acid

Abstract

A series of SiO 2 /polyimide hybrid films with different contents and sizes of SiO 2 particles were prepared by blending polyamic acid (PAA) and SiO 2 nanoparticles obtained from Stö ber method, followed by a step thermal imidization process. The size and content effect of SiO 2 particles on the mechanical and thermal properties was studied. It was found that as the silica particles were introduced into polyimide matrix, T g s of hybrid films increased on the whole and there was a maximum value of T g for the hybrid film with 10-nm SiO 2 particles. TGA indicated that the thermal stability for hybrid films decreased with the increasing content and size of SiO 2 particles. Dynamic mechanical thermal analysis (DMTA) indicated that the modulus of hybrid films increased, while the tensile strength and elongation at break decreased as the size of SiO 2 particles increases from 10 to 25 nm and to 65 nm. All polyimide hybrid films were amorphous according to X-ray determination.

Preparation of magnetic polyimide/maghemite nanocomposite fibers by electrospinning

“…This phenomenon could be due to the massive agglomeration of magnetic nanoparticles in the fibers, less interfacial interaction, and compatibility between the polymer and g-Fe 2 O 3 phase resulted in the less efficient stress transfer process. 32 Due to the rigid nanoparticles, the elongation at break decreased with increasing the content of Fe 3 O 4 . It was noticed from Table 1 that there was no significant influence of iron oxide nanoparticles on the mechanical properties of PI fiber membranes.…”

Fabrication and properties of polyimide composites filled with zirconium tungsten phosphate of negative thermal expansion

“…indicates that some ZWP powder dispersed in the PI matrix in an exfoliation morphology, while more powder is embedded in the PI matrix. These embedded particles with small size may be benefit to the improvement of thermal properties [12].…”

“…From the results of FTIR ( Fig.4) and SEM (Fig.5), ZWP particles (about 320nm in size) disperse in fully imidized PI matrix. These small particles may have strong interaction with the colloidal PI matrix and can act as efficient physical cross-linking points to restrict the segmental motion of polymers [12,29]. With the increment of ZWP powder, more powder acting as the efficient physical cross-linking points would be obtained.…”

“…To reduce the TEC of PIs, forming hybrid PI composites with inorganic filler materials is a promising approach [1]. In recent years, many researches have been carried out to tune the properties of PIs by incorporating inorganic materials, such as silica particles [1,12], TiO 2 nanoparticles [13], montmorillonite [14], CNT [15], Ti [16] or Al 2 O 3 [17], etc. However, the reduction in TEC by these particles is limited because of the positive TEC of the fillers [11].…”

High‐performance polyimide film based hybrid nanostructures: Synthesis, characterization, and properties investigation

“…On the other hand, PI‐based hybrid nanocomposites have also been studied such as ZnO‐CNTs, chitosan‐CNTs, oraganic–inorganic nanohybrids, silica–silver hybrids, surface‐silvered graphene‐CNTs, Co 0.5 Ni 0.5 Fe 2 O 4 /CNTs and Pt/carbon, polymethyl methacrylate (PMMA)‐grafted‐MWCNTs. PI‐based nanocomposites and hybrids have shown good mechanical properties , thermal properties , electrical properties , photochemical properties , electrochemical properties , physical properties and tribological properties . Pure PI has tensile strength of 120–140 MPa .…”