Effect of montmorillonite on thermal and moisture absorption properties of polyimide of different chemical structures

Abstract

ABSTRACT:The thermal properties and the moisture absorption of three types of polyimide/montmorillonite nanocomposite were investigated: 3,3Ј,4,4Ј-biphenyltetracarboxylic dianhydride-4,4Ј-oxydianiline (BPDA-ODA); pyromellitic dianhydride-ODA (PMDA-ODA); and 3,3Ј,4,Ј-benzophenone tetracarboxylic dianhydride-ODA (BTDA-ODA). The inhibition effect on in-plane coefficients of thermal expansion (CTE) and moisture absorption of these polyimide nanocomposites by layered silicates from montmorillonite was found to decrease with the crystallinity in the pristine polyimides. The largest reduction, 30% in in-plane CTE occurred in the case of amorphous BTDA-ODA containing 5 wt % montmorillonite as compared with that of pure BTDA-ODA, while the reduction in in-plane CTE was 20% for the case of semicrystalline BPDA-ODA. The maximum reduction in moisture absorption, 43%, also took place for the case of 3/97 ODA-Mont/BTDA-ODA as compared with that of pure BTDA-ODA, whereas the semicrystalline 1/99 PPD-Mont/BPDA-ODA showed a 30% reduction as compared with that of pure BPDA-ODA.

Effect of clay on properties of polyimide‐clay nanocomposites

“…PIclay nanocomposites exhibit lower CTE than that of pristine PI, which is a general trend known from literature. 15,[17][18] However, explanation of this trend is not consistent. Wei et al 15 believed that the crystallinity of PI holds the CTE down and the CTE of crystalline PI is substantially lower than that of amorphous PI.…”

“…Clay materials would reduce the CTE of PI but in different extent. 15 However, the effect of clay is not explained. Yano et al 17 and Chang et al 18 both attributed the low CTE of nanocomposites to the much lower CTE of clay than that of pristine PI.…”

Synthesis and characterization of fluorinated polyimides derived from 1,4-bis-[4-amino-2-(trifluoromethyl)-phenoxy] benzene/tetrafluoride benzene

“…The moisture uptakes of aromatic PIs were up to 3.0-3.5% depending on the chemical structure of polymer and the relative humidity of the environments. [27] However, the moisture absorptions of some FPIs could be reduced to less than 1%. Two methods were used to measure the moisture uptakes in this paper and the results are listed in Table 5.…”

Gelatin blended with Cloisite 30B (MMT) for control release of Ofloxacin

“…[15][16][17] This may be promising method to enhance the gelatin properties for biomedical applications.…”