2.3 Characterization
Fourier transform infrared spectroscopic (FTIR) spectra were obtained by
Nexus 670 (Thermo Nicolet, America). The data was collected in
attenuated total reflection (ATR) mode with the wavenumber range from
400 cm-1 to 4000 cm-1. XRD spectra
were recorded on Rigaku SmartLab diffractometer with the Cu Kα at
the voltage of 40 kV and current of 30 mA over the 2θ angular
range of 2 o~30 o at
the scanning speed of 10 o/min. SEM image was
processed on S-4800 (Hitachi, Japan) at an accelerating voltage of 10
kV. Oxygen transmission rate (OTR) was conducted on G2/132 (Labthink,
China) based on the differential pressure method. Water vapor
transmission rate (WVTR) was determined using W3/330 (Labthink, China)
with a sample test area of 5 cm2 at 37.8oC and 77.0 %RH (±1 %RH). The limiting oxygen index
(LOI) values were collected by the YZS-75A oxygen index meter (Bei Guang
Jing Yi, China) according to GB/T 2406.1-2008. MMT-PI film was fixed 2
cm above the heat source (alcohol lamp flame) and the pseudocolor
thermal imager was set at a specific distance for fire-resistance
measurement. The thermal infrared imager VH-780 (Infra Tec, Germany) was
used the capture pseudocolor thermal images during the 90 s video
recording. The test method for water absorption is as follows. The MMT
film, MMT-PI, MMT-PVA, and MMT-CMC were completely immersed in deionized
water and placed under room temperature and pressure for 3 days. The
films were then taken out, and water adhering to the surface of the
films was quickly wiped off and weighed immediately. The water
absorption rate (WA%) was calculated accruing to Eq. 1 .