| الملخص | Summary
This study aimed to prepare pure (activated bentonite) clay with reduced particle size which is starting material to produce better physical and chemical properties of organoclay and poly nano-composite. Reduced particle size of clay was prepared from agitation process, which produced a purified and reduced particle size of activated bentonite for a period of time, [D50 and D90 (particle size distribution)] equal to (198 and 10027nm) respectively. Another stage was used to improve (D50 and D90) of the reduced particle size clay by using shear mixing method giving (D50 and D90) equal to (157 and 5533 nm) respectively at speed=3 and time of (30 min). Organoclay was prepared from reaction of quaternary amine (cetyl tri-methyl ammonium chloride) with reduced particle size of clay at optimum condition of (20 %) quaternary amine to reduced particle size of clay give increasing in d-space (from X-RAY pattern) from (12˚A to 16.8˚A). Poly nano composite was studied by in-situ intercalation method using acrylonitrile as monomer and the reduced particle size of clay, different concentrations of clay and acrylonitrile were tested, best concentration of acrylonitrile to reduced particle size of clay was (5 %) giving d-space (from X-RAY pattern) equal to( 13.6˚A).
Key words:- bentonite, organoclay, polyacrylonitri-composite .
Introduction
Typically, the chemical structures of montmorolonite (MMT) consist of two fused silica tetrahedral sheets that sandwich an edge shared octahedral sheet of either magnesium or aluminum hydroxide. The layered silicate commonly used in nano-composite belongs to the structured family known as the (2:1) phyllosilicates. The Na+ and (Ca+2) residing in the interlayer regions can be replaced by organic cations such as alkyl ammonium ions, by cationic–exchange reaction to render the hydrophilic clay to organophilic (Kshash and Sabber, 2012) . The polymer layered silicate nano composites (PLSNs) are emerging as the most significant and new breed of composite material due to their extensively enhanced mechanical, thermal flammability (Wang, et, al., 2002). These properties of polymerlayered silicate arise from the maximized contact between the organic and inorganic phase, so fillers with high surface - to - volume ratio are commonly used . Unlike to a virgin polymer or conventional micro and macro composite, the improvement in properties of (PLSNs) is remarkable, including high module, increased strength and heat resistance decreased gas permeability and increased biodegradability (Sahoo , et. al.,2011).
Experimental Work
The preparation method applied in this work as follows:
1-Activated Na-Bentonite was preliminary treated with water at solid percent of (0.5 %) for a period of time to reduced and purified clay particles and increase surface area then subjected to high shear mixer device (Hamilton Beach Mixer, Type GM 20) at different times (10, 20 and 30) min and various speeds [1, 2 and 3].
2-The produced bentonite clay from high shear mixing with (80 %) of particles (< 1µm) were mixed with, Cetyl Trimethyl Ammonium Chloride in two ratios (15 and 20) % wt./wt.then dried at (60 oC) to prepare organoclay or mixed with acrylonitrile at different Bentonite / acrylonitrile ratios (3, 6, 15, 30, 60) % wt./wt. to prepare Nano-Composites. The mixture poured in to (250 ml) flat-bottom flask pre-heated into (50 oC) in a water bath, and then injected with (N2) gas for about (10 min) , polymerization then started by adding redox initiator composed from (Na2S2O5, FeSO4.7H2O and Na2S2O8) and the temperature set proceed at (50 oC) for about (60 min) . The product was then decanted from water and filtered out, then subjected for (XRD) analyses .
Discussion and Conclusions
-The first series of tests were conducted to optimize the time and speed of high shear mixing used for reducing particles size of the clay. The experiments were carried out at three different speeds and time (10, 20 and 30) min , the results are presented in table (1) and the (XRD) pattern. It can be seen, that in every increase in high shear mixing time and speed gain reduced particles of clay with (D50) of about (150 nm) and a (D90) of about (5500 nm) for about (30 min) and at speed three.
- The second series of tests were conducted to prepare organoclay by adding ratios of Cetyl Tri-methyl Ammonium Chloride (Quaternary Ammonium Salt, QA) to a certain amount of reduced particles of clay (15 and 20) g of QA% wt./wt. Figures (2 and 3) show (XRD) pattern for organoclay (15 % QA and 20 % QA) respectively.The d space was increased from (12 Ao) in the activated bentonite to (13.5 Ao) in the reduced particles to about (14.1 and 16.8 Ao) for (15 % and 20 % QA) respectively in the organoclay.
-The third series of experiments includes intercalation of polymers in layered hosts, such as layered silicates, has proven to be a successful approach to synthesize PLS nano-composites. In this study, the in-situ intercalative polymerization method applied using acrylonitrile monomer and the reduced particles of clay. Experiments have been conducted using several doses of reduced particles of clay to the monomer (acrylonitrile) charge . According to the results in table (2) d-space values did not increased above (14 Ao) thus no or very weak intercalated interlayer have been existed . The conclusions of this research as follows
-Particle size of activated bentonite could be reduced by agitation and shear mixing method giving particle size distribution with (D50 and D90) equal to (198 and 10027nm) respectively.
-Organo clay could be produced from reduced particle size of activated bentonite by reaction with quaternary amine
-In-situ intercalative polymerization method was not fruitfully work with reduced particles of clay.
References
1-Kshash, J. M., and Sabber, B., 2012. Preparation of Orgnoclay from Iraqi Bentonite for the Removal of Oil Pollution from Produced Water. GEOSURV-Iraq, Int. rep. no. 3404
2-Sahoo, P.K., Biswal, T., Samal, R., 2011. Microwave-Assisted Preparation of Biodegradable Water Absorbent Polyacrylonitrile/Montmorillonite Clay Nanocomposite, Jour. of Nanotech., P1
3-Wang, W., Hu, Y., Song,L., Chen, Z., Fan,W., 2002. Polym. Degard. Stab., Vol. 77, pp. 423
High Shear Mixing Time (min)
High Shear
Mixing Speed Particle Size Distribution (nm)
D 50% D 90%
10 1 225 10449
2 232 9105
3 232 9288
20 1 228 10410
2 223 9042
3 212 8540
30 1 236 9316
2 216 8747
3 157 5533
Table 1: Particle distribution at different speed and time of high shear mixing of clay.
Fig.1: XRD Pattern of the reduced particles
Table 2: d –space of nano-composite for different clay and acrylonitrile doses.
Sample No. Clay (%) Acrylonitrile (%) d-Space
PNC1 3 100 12.74494
PNC2 6 100 12.45593
PNC3 15 100 12.58300-13.92015
PNC4 30 100 12.60829-13.23936
PNC5 60 100 13.06043
PNC6 100 2.5 13.13785
PNC7 100 5 13.60420
PNC8 100 10 12.23875 | en_US |
