Zirconium Phosphate/Fibrous Cerium Phosphate Nanocomposite Membrane Self Supported Benzimidazole, Its Co-Aniline, Co-Pyrrole and Co-Indole Polymerization Agent

Nanosized zirconium phosphate and nano fibrous cerium phosphate , Zr(HPO4)2.H2O(nZrP) , Ce(HPO4)2.2.9H2O (nCePf), respectively, were prepared and characterized. Mixing slurry aqueous solution of (nZrP and nCeP f ) in 25:75 wt/wt% mixing ratios) , respectively, lead to formation of novel zirconium phosphatefibrous cerium phosphate nanocomposite membrane, [Zr(HPO4)2]0.25[Ce(HPO4)2]0.75.3.87H2O(nZrP-nCePf), was characterized. Zirconium phosphate-fibrous cerium phosphate/ polybenzimidazole-/polybenzimidazolee-co-polyaniline/polybenzimidazole-co-polypyrrole-/polybenzimidazole-co-polyindole nanocomposite membranes were prepared via in-situ chemical oxidation polymerization of the benzimidazole, and its co-monomers in alcohol, that was promoted by the reduction of Ce(iv) ions present in the inorganic matrix of (nZrP-nCePf ) nanocomposite membrane. A possible explanation is nCePf , present on the surface of composite membrane, is attacked by benzimidazole and its co-monomers , converted to cerium(III) orthophosphate(CePO4). The resultant materials were characterized by elemental (C,H,N) analysis , FT-IR, and scanning electron microscopy(SEM) .. SEM images of the resulting nanocomposites reveal a uniform distribution of the polybenzimidazole and its co-polymers on the inorganic matrix. From elemental (C,H,N) analysis the amount of organic material (PBI) present in (nZrP-nCePf)/PBI composite found to be = 5.7% in wt.. T.he amount of organic materials present in copolymers found to be for (nZrP-nCePf)/PBI-co-PANI (PBI = 9.33%, PANI= 13.32% in wt)., for (nZrP-nCePf) /PBI -co-PPy (PBI = 12.85%, PPy = 7.1% in wt) , and for (nZrPnCePf) /PBI-co-PIn ( PBI = 16.47% , PIn = 8.81% in wt).

Polyindole (PIn) is an electro active polymer, owns advantages especially fairly good thermal stability [37,38]. Polyindole can be obtained from chemical, electrochemical and interfacial polymerization of indole [37,38]. Its electrical and electrochemical properties show great promise for commercial applications [39,40]. Some studies shows polyindole has similar properties like polyaniline, based on their high conductance and good environmental stability [41,42].
Inorganic layered tetravalent metal phosphates nanomaterials are receiving great attention because of their size, structure, and possible biochemical applications [51,52], that have been proven to be good carriers for organic polar molecules. These materials are good thermal stability and does not change on aging. Examples of these are zirconium phosphates. Taking advantage of the expandable of their layered.
Cerium phosphates have been studied for a long time as ion exchangers, their structures remains unknown until recently [53][54][55]. The reason is that, the composition, the structure and the degree of crystallinity of their precipitates results from reaction of solutions containing a Ce IV salt is mixed with a solution of phosphoric acid of [(PO 4 )/Ce(iv) ratio], strongly dependent on the experimental conditions such as rate and order of mixing of the solutions, stirring, temperature and digestion time, this also implemented on fibrous cerium phosphate [50,56]. To date most of the work on fibrous cerium phosphate was carried out on its ion exchange [57], intercalation [58] and electrical conductance properties [59], on its poly(vinylalcohol) [60] and (polyvinyl chloride-based polyvinylalcohol) composites have been reported [61].
Nanoscaled tetravalent metal phosphates and their organic polymer composites comprise an important class of synthetic engineering. However; research in such area is still Terra incognita [62][63][64][65]. Nanotechnologies are at the center of numerous investigations and huge investments. Chemistry has anticipated for long the importance decreasing the size in the search of new properties of materials, and of materials structured at the nanosize in a number of applications relate to daily life. Organic-inorganic nanocomposite membranes have gained great attention recently [64,66]. The composite material may combine the advantage of each material, for instance, flexibility, processability of polymers and the selectivity and thermal stability of the inorganic filler [63][64][65][66][67].

Preparation Of Zirconium Phosphate-Fibrous Cerium Phosphate Nanocomposite Membrane(Nzrp-Ncep f )
Slurry aqueous solution of 0.15g of Zr(HPO 4 ) 2 .H 2 O (nZrP) in 20ml distilled water was added gradually to 150ml of slurry aqueous solution of fibrous cerium at 45°C , with stirring for 48h. The resultant product was filtered in Buchner funnel , washed with distilled water and dried in air.

Preparation of Nzrp-Ncep f / PBI Nanocomposite Membrane
0.132g of nZrP-nCeP f was immersed in 5ml 4% benzimidazole in ethanol at room temperature for 48h. Then the impregnated sheet was removed, washed with distilled water and ethanol and left to dry in air. The colour of the resultant product was beige.

Preparation of Nzrp-Ncep f / PBI-Co-Pani Nanocomposite Membrane
0.2g of nZrP-nCeP f composite sheet was immersed in a mixture of 10 ml 4% aniline and 10ml 4% benzimidazole in ethanol at room temperature for 48h.. The obtained composite membrane was washed with ethanol and left to dry in air. The colour of the resultant product was green.

Preparation of Nzrp-Ncep f / PBI-Co-Ppy Nanocomposite Membrane
0.2g of nZrP-nCeP f composite sheet was immersed in a mixture of 10ml 4% pyrrole and10ml 4% benzimidazole in ethanol, at room temperature for 48h. The obtained composite membrane was washed with ethanol and left to dry in air. The colour of the resultant product was green.

Preparation Of Nzrp-Ncep f / PBI-Co-Pin Nanocomposite Membrane
0.2g of nZrP-nCeP f composite sheet (0.2g) was immersed in a mixture of 10ml 4% indole and 10ml 4% benzimidazole in ethanol at room temperature for 48h. The obtained composite membrane was washed with ethanol and left to dry in air. The colour of the resultant product was brown.

TGA of nCeP f
Thermogram of (nCeP f ) is shown in Figure 2. The thermal decomposition occurs in continuous process, The thermal analysis was carried out at temperatures between 10-775°C, the final product was CeP 2 O 7 . Loss of water of hydration occurs between 60-200°C, followed by POH groups condensation. The total weight loss found to be equal to 19.09%.   Figure 4. The photograph shows its average size is ~20.5 nm.

TEM of nCeP f
Transmission electron microscopy image(TEM) of the nanosized fibrous cerium phosphate(2% in wt in PVA) , is shown in Figure 5. Its average size found to be ~15nm.

Ion Exchange Capacity of Ncep f
The ion exchange capacity of nanosized fibrous cerium(iv) phosphate , Ce(HPO 4

SEM of nZrP
SEM morphology image of the nanosized zirconium phosphate is shown in Figure 7. The photograph shows its average size in the range 48nm. Its interlayer distance (d 001 ) found to be equal to7.65Å. Fig-7. SEM morphology image of nZrP.

TEM of nZrP
Transmission electron microscopy image (TEM) of the nanosized zirconium phosphate is shown in Figure  8.The photograph shows its average size is ~85.7nm.

FT-IR of nZrP
The FT-IR spectrum are a key tool to detect the presence of water molecules as well as to investigate the Hbonds structure different forms with very different structures. Structures of the sample morphology in the FT-IR analysis allows understanding the structural changes involved in phase transition, proton exchange and hydrationdehydration process. Figure 9 shows FT-IR spectrum of nZrP , consists of broad band centered at ~ 3250 cm -1 The two sharp side bands at 3590 and 3500 cm -1 , represent good crystallinity, include range of broad band, were attributed to symmetric asymmetric vibration of hydroxyl groups of water of crystallization. Sharp band at~ 1600 cm -1 , assigned for H-O-H bending .The broad band, with two small sharp band at 1250, 965 cm -1 with maxima at ~1040 cm -1 , is characteristic of the vibration of orthophosphate groups. The bands at the region 600-~400 cm -1 are ascribe the presence of δ(PO 4 ) .

Ion Exchange Capacity of nZrP
The ion exchange capacity of nanosized zirconium phosphate found to be equal to 6.66 meq/g. Zirconium phosphate fibrous cerium phosphate nanocomposite membrane was prepared and characterized by XRD, TGA and SEM.  Figure 10 shows two major peaks equal to 11.31Å and 7.81Å which are related to the interlayer distance of their parent materials which shows the formation of the composite. The first d value concern nCeP f the second one is related to nZrP.  Figure 11. The thermal analysis found to occur in three stages. The first stage is related to the loss of water of hydration between 75-240°C, followed by POH groups condensation up to 800°C. The total weight loss found to be equal to 20.1%. The final product was [Zr 0.25 -CeP 0.75 ]P 2 O 7 The thermogra is accomponed with four endothermic peaks.

FT-IR Spectra of nZrP-nCeP f / PBI Composite
FT-IR spectrum of nZrP-nCeP f / PBI composite is shown in Figure 13 , consist of broad band centered around ~ 3435cm -1 , is due to OH groups symmetric stretching of H 2 O super imposed with the N-H stretching of aromatic amines (expected at the range 3695.9-.3000cm -1 ),. Small band around ~1 628 cm -1 is related to H-O-H bending , and sharp broad band centered at 1000.cm -1 is corresponds to phosphate groups vibration. Small bands at ~ 2924 , 2856cm -1 corresponds to C-H bonds, The presence of two bands in the range of 1600-1300 cm -1 is assigned to the (C=C stretching vibration of quinoid ring), while the lower frequency mode at ~1 100cm -1 depicts the presence of benzenoid rings . However the higher frequency vibration has a major contribution from the quinoid rings (C=C stretching vibration of quinoid ring), Thus FT-IR spectrum confirms the formation of polymerization. Fig-13. FT-IR spectrum of ( nZrP-nCePf)/PBI nanocomposite.

FT-IR of (nZrP M2 -nCeP f )/ Polybenzimidzole-Co-Polypyrrole Nanocomposite
FT-IR spectrum of polybenzimidazole-co-polypyrrole nanocomposite copolymer is shown in Figure 17. A broad band cantered at 3400 cm -1 , due to the characteristic stretching vibration OH groups symmetric of H 2 O, superimposed with that of N-H stretching of aromatic amines. Small bands at the range 2960-2865cm -1 could be attributed to N-H stretching. Bands in the region 1680-1600cm -1 are related to stretching C-C bonds characteristic of pyrrole unites C-H (aromatic) stretching, C=C stretching. C-N stretching (between two indole units), are in the region 1570-1370cm -1 .The presence of bands in the range 1455-1373 cm -1 is assigned to the non-symmetric C6 ring stretching modes and contribution from the quinoid rings, the presence of benzenoid units. However, the characteristic band for polybenzimidazole are found in the range of 1487-1176cm -1 . Small sharp band at 1625 cm -1 is related to H-O-H bending, Sharp broad band centered at 1040 cm -1 is corresponds to phosphate groups vibration .  Figure 19 shows FT-IR spectrum of nZrP M2 .nCeP f / polybenzimidazole-co-polyindole nanocomposite membrane. A broad band cantered at 3400 cm -1 , due to the characteristic stretching vibration OH groups symmetric of H 2 O, superimposed with that of N-H stretching of aromatic amines. Small bands at the range 2960-2865cm -1 could be attributed to N-H stretching. bands in the region 1680-1600cm -1 are related to stretching C-C bonds characteristic of pyrrole unites C-H (aromatic) stretching, C=C stretching. C-N stretching (between two indole units), are in the region 1570-1370cm -1 . The presence of bands in the range 1455-1373 cm -1 is assigned to the nonsymmetric C6 ring stretching modes and contribution from the quinoid rings, the presence of benzenoid units of polyindole . However, the characteristic band for polybenzimidazole are found in the range of 1487-1176cm -1 . Small sharp band at 1625 cm -1 is related to H-O-H bending. Sharp broad band cantered at 1040 cm -1 is corresponds to phosphate groups vibration. Fig-19. FT-IR of (nZrPM2-nCePf)/ polybenzimidazole-co-polyindole nanocomposite 3.16.6. SEM of (nZrP-nCeP f )/ polybenzimidazole-co-polyindole nanocomposite Figure 21 shows SEM image for (nZrP-nCePf)/polybenzimidazole-co-polyindole nanocomposite membrane, reveal a distribution of the co-polymer on the inorganic matrix
The presence of Ce(iv) ions allows redox reactions necessary to oxidative polymerization to occur. A possible explanation is that polymerization of BI and its co-monomers were promoted by the reduction of some of nCePf present in inorganic composite membrane (nZrP-nCeP f ), that attacked by BI , and its co-monomers, respectively, converted to cerium(III) orthophosphate (CePO 4 ).
The formulation of the resultant conducting polymers nanocomposites was supported by elemental(C,H,N) analysis, FT-IR spectra and SEM. Colour changes supports the formation of the resultant organic polymers composites . We suggest self doping occurred on polymerization, which is due to H + present in (ZrO 3 POH) groups.
Beneficial properties of the resultant nanocomposites can be considered these composites as novel conducting inorganic-organic composites, ion exchangers, solid acid catalyst and as sensors.