1190
F.A. Morsy et al.
instrument, A tear tester (L&W 2404) was used according to Tappi 496. All optical tests were qualitative and conducted using integrating reflectometer, model JY9800. The instrument has multifunction; it can be used to measure brightness, white- ness, and opacity. The prepared handsheets’ brightness was measured according to ISO 2470:1999. The degree of whiteness was measured according to ISO 11475:1999. The opacity was measured in accordance with ISO 2471:1998.
3. Results and discussion
3.1. XRF chemical analysis
Table 1 shows chemical analysis of SBRSA sample as received by using XRF analysis. The results show that the percentage of SiO 2 is 62.5% and the moisture content is 7.4%. Table 2 represents XRF analysis of thermally treated SBRSA sample. The percentage of silica increased to be 82.9%. The XRF analysis of silica nano-particles indicates that the produced silica has a high purity reaching to 99.8% (Table 3). Table 4 shows that the prepared SiO 2 /CaCO 3 nano- composites (CS1, CS2 and CS3) have SiO 2 contents of 1.82%, 2.12% and 2.99%, respectively. It is found that the amount of SiO 2 in the produced composites increased with increasing the concentration of SiO 2 :CaCO 3 molar ratio in the coating process.
Figure 4
TEM micrograph of silica nano-particles prepared
from thermally treated SBRSA.
The thickness was measured based on Tappi 411 using L&W micrometer 51. The density was calculated according to the following equation: d ¼ 1000 G = t ð 2 Þ where: d = density, kg/m 3 , G = grammage, g/m 2 , t =thick- ness, l m. Bursting was measured using Frank GmbH 1882 burst tes- ter according to Tappi 807. Hounsfield H5KS tensile tester was used to measure tensile strength according to Tappi 404. The internal tearing strength was measured on a pendulum type
3.2. FT-IR spectrum
The major chemical groups present in silica nano-particles prepared from thermally treated SBRSA are identified by the
Figure 5
TEM images of CaCO 3 core particles (C) and SiO 2 /CaCO 3 nanocomposites (CS1), (CS2) and (CS3).
Made with FlippingBook - Online magazine maker