Spectroscopic characterization of linseed oil based polymer nano-composites

Polymer Testing 27 (2008) 916–923

Contents lists available at ScienceDirect

Polymer Testing journal homepage: www.elsevier.com/locate/polytest

Chemical Analysis

Spectroscopic characterization of linseed oil based polymer nano-composites Vinay Sharma a, b, J.S. Banait b, P.P. Kundu a, * a b

Department of Chemical Technology, Sant Longowal Institute of Engineering and Technology, Sangrur, Punjab 148106, India Faculty of Physical Sciences, Punjabi University, Patiala, Punjab 147002, India

a r t i c l e i n f o

a b s t r a c t

Article history: Received 15 May 2008 Accepted 18 July 2008

Conjugated linseed oil based nano-composites from thermal polymerization have been investigated quantitatively through 1H NMR and FTIR spectroscopic techniques. The solubility of samples measured by soxhlet extraction ranges from 28 to 55% for varying linseed oil content (30–70%) and 28 to 43% for the samples with varying montmorillonite clay content (0–10%). The content of grafted linseed oil calculated from 1H NMR results ranges from 2 to 19% with varying oil content (30–70%) and 7 to 22% with varying clay content (0–10%). The FTIR results show variation in grafted linseed oil content from 2 to 19% with varying oil content (30–70%) and 6 to 23% with varying clay content (0–10%). The clay embedded in the polymer matrix, calculated from FTIR results, ranges from 3 to 5% with varying oil content (30–70%) and 0 to 8% with varying clay content (0–10%). Ó 2008 Elsevier Ltd. All rights reserved.

Keywords: Linseed oil polymers 1 H NMR FTIR Quantification Nano-composite

1. Introduction Polymer layered silicate nano-composites have received great attention in the last decade due to their enhanced properties compared to the pristine polymer or to conventional composites [1–4]. To date, many polymer nano-composites have been reported [5–14]. They are especially attractive as their mechanical, thermal and electrical properties can be improved and new high quality compounds can be easily designed [15]. Several types of clay, such as montmorillonite, saponite, mica, illite, kaolinite, vermiculite and sepiolite are used as fillers [16]. Amongst these, montmorillonite is the most preferred nano-filler due to the largest surface area and the highest cation exchange capacity [17]. The silicate can be dispersed in a liquid monomer or a solution of monomer. It is also possible to melt-mix polymers with layered silicates, avoiding the use of organic solvents [18–20]. The latter method permits the use of conventional processing techniques, such as injection molding and extrusion.

* Corresponding author. E-mail address: [email protected] (P.P. Kundu). 0142-9418/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.polymertesting.2008.07.008

Spectroscopic techniques are important procedures to characterize various polymers [20–23]. These techniques are powerful tools for the characterization of the polymers both qualitatively [24] and quantitatively [25]. A lot of research work has been published previously on the quantitative analysis of clays and nano-composites by NMR and FTIR [26–29]. In the present work, linseed oil nano-composites have been synthesized and studied quantitatively by 1H NMR and FTIR. A lot of research work has already been carried out on the quantification of the formation of polymers during polymerization from monomers through FTIR [30–32]. However, the present work reports the complete analysis of linseed oil nano-composites through 1H NMR and FTIR. 2. Experimental 2.1. Materials Conjugated linseed oil (87% conjugation) was purchased from Alnor Oil Company, NY, USA. Acrylic acid and tetrahydrofuran were purchased from Merck Chemical Co.,

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

Germany. Divinylbenzene was purchased from Fluka Chemie. Montmorillonite (K-10), cetyl trimethyl ammonium bromide and hexadecyl ammonium bromide were purchased from Aldrich Chemical Company (Milwaukee, MI) and were used as-received. 2.2. Sample preparation

917

A sample ranging from 2 to 3 g of the bulk polymer was extracted for 24 h with 150 mL of refluxing tetrahydrofuran. After extraction, the resulting solution was concentrated by rotary evaporation and subsequent vacuum drying. The insoluble solid was dried under vacuum for several hours before weighing. 3.2. 1H Nuclear magnetic resonance (1H NMR)

2.2.1. Modification of montmorillonite Montmorillonite clays were dispersed in DI water by stirring. Cetyl trimethyl ammonium bromide (CTAB) or hexadecyl ammonium bromide (HDAB) was added to the dispersion. The whole dispersion was heated at 80  C for 4 h. The exchanged clays were filtered and washed with DI water until they were free from bromide (tested by titration with silver nitrate). The modified clay was dried at 80  C under vacuum. The cation exchange capacity (CEC) of the modified clay was calculated by titrating the supernatant against a standard iodine solution. Only those sodium ions which are exchanged during stirring of the clay react with iodine, giving the equivalent weight of the sodium in the supernatant. CEC (cation exchange capacity) calculated from the titre value for CTAB was 29.92 and for HDAB 152.84 meq/100 gm of clay. 2.2.2. Nano-composite preparation The polymeric nano-composites were prepared by heating the desired mixture of conjugated linseed oil, acrylic acid, divinylbenzene and modified montmorillonite in a glass vial. The detailed compositions are reported in Table 1. The dispersion was maintained by constant magnetic stirring at 500 rpm (overnight for proper intercalation). The mixture was heated at 85  C for 2 h, followed by 1–4 h at 95  C such that the viscosity of the liquid (prepolymer) was sufficiently high and fillers became totally exfoliated. In this condition, the fillers will not be separated from the pre-polymer when stirring is stopped. The whole mass was transferred to an appropriate mould and put in an oven at 100  C for 2 h, 120  C for 12 h and 130  C for 12 h. 3. Characterization 3.1. Soxhlet extraction The polymeric materials as reported in Table 1 were soxhlet extracted for their soluble and insoluble contents.

The extracted soluble part of the polymeric material as well as the linseed oil, styrene and divinylbenzene was dissolved in CDCl3. Tetramethylsilane (TMS) was used as a reference compound to compare the obtained data. The solution was scanned with a multinuclear FT-NMR spectrometer (Bruker AC-300 F) at 300 MHz. A total of 30 scans were averaged to obtain the final data. 3.3. Fourier transform infra-red spectroscopy The dried insoluble part after soxhlet extraction was analyzed by FTIR spectrometry using a Perkin–Elmer RX-I spectrophotometer. Samples were prepared by the KBr pellet method and spectra were collected as a sum of 32 scans at a resolution of 4 cm1. Specifically, about 1 mg of finely powdered polymer sample was mixed with 100 mg of KBr powder in a mortar and pestle. The mixture was then pressed in a die at about 100 MPa pressure for 3 min to get a transparent disk. This disk was then placed in a sample holder and the peak transmittance recorded. 4. Results and discussion 4.1. Soxhlet extraction Polymeric samples were extracted for their insoluble content and these results are reported in Table 2. The plot between the content of linseed oil and soluble content of the nano-composite sample is shown in Fig. 1. For the nanocomposite samples at fixed clay contents (5%), the increase in the oil content from 30 to 70% in the samples leads to a decrease in insoluble content from 72 to 43% and an increase in the soluble part from 28 to 57%. These results indicate that with the increase of linseed oil content, the cross-linking density of the polymeric samples decreases. For the variation of filler from 0 to 10% at a fixed composition of the polymer, the soluble portion decreases from 45

Table 1 Detailed composition of the polymer samples prepared from linseed oil Sample ID

Conjugated linseed oil (%)

Divinylbenzene (%)

Acrylic acid (%)

Clay montmorrilonitea (K-10) (%)

CLin30 Clin40 CLin50 CLin60 CLin70 CTABMONT2.5 CTABMONT7.5 CTABMONT10 HDABMONT2.5 MONT0

30 40 50 60 70 50 50 50 50 50

10 10 10 10 10 10 10 10 10 10

60 50 40 30 20 40 40 40 40 40

5 5 5 5 5 2.5 7.5 10 2.5 0

a

The clay is modified by using Cetyl trimethyl ammonium bromide (CTAB), or hexadecyl ammonium bromide (HDAB).

(CTAB) (CTAB) (CTAB) (CTAB) (CTAB) (CTAB) (CTAB) (CTAB) (HDAB)

918

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

Table 2 The detailed compositions of the thermally crosslinked nano-composites of conjugated linseed oil, acrylic acid and divinylbenzene copolymers from soxhlet extraction and 1H NMR spectroscopic results Sample ID

CLin30 CLin40 CLin50 CLin60 CLin70 CTABMONT2.5 CTABMONT7.5 CTABMONT10 HDABMONT2.5 MONT0

Soluble extractible compositiona

Soxhlet results

Wt% of oil

Wt% of AcA & DVB

Solubleb (wt%)

Insolublec (wt%)

98.11 96.21 96.03 95.06 95.58 94.52 94.09 95.37 93.1 95.82

1.99 3.79 3.97 4.94 4.42 5.48 5.91 4.63 6.9 4.18

28.53 33.14 36.80 43.48 57.49 29.69 39.28 40.18 48.65 44.85

71.47 66.86 63.20 56.52 42.51 70.31 60.72 59.82 51.35 55.15

(27.99j0.54) (31.88j1.26) (35.34j1.46) (41.33j2.15) (54.95j2.54) (28.06j1.63) (36.96j2.32) (38.32j1.86) (42.29j3.36) (42.98j1.87)

(2.01j69.46) (8.12j58.74) (14.66j48.54) (18.67j37.85) (15.05j27.46) (21.94j48.37) (13.04j47.68) (11.68j48.14) (7.71j46.64) (7.02j48.13)

a Microcomposition of the extracted soluble materials calculated from the 1H NMR integrals of the glyceride peak at 4.1 ppm, acrylic OH peak at 9.8 ppm and aryl CH peak at 7 ppm. b The data in parentheses have been calculated directly from the wt% of oil and wt% of acrylic-DVB contents in the soluble extract. The first value in the parentheses represents the percent oil contents and the second value represents the percent acrylic-DVB contents. c The data in the parentheses have been calculated indirectly from the weight % of the oil and acrylic-DVB contents in the soluble extract; as the total mass of the soluble and insoluble parts held constant. The first value in the parentheses represents the percent oil contents and the second value represents the percent acrylic-DVB contents.

to 30% and the insoluble portion increases from 55 to 70%. The variation in soluble content with increase in the filler content is shown in Fig. 1. The soluble content reduces from the level for the pure polymer to a minimum at the 2.5% filler level and then increases with further increase of filler content up to 10% (from Fig. 1). 4.2. 1H NMR of linseed nano-composites Amongst the monomers (linseed oil, acrylic acid and divinylbenzene) used for the preparation of nanocomposites, linseed oil is the least reactive one. Thus, it is expected that a large amount of linseed oil should remain unreacted, leading to an increase in the soluble fraction of the polymers. 1H NMR spectra of pure AcA, DVB, CLin, the solvent and the soluble extract from the polymeric sample (CLin50) are shown in Fig. 2. The extracts from CLin50 are representative of the soluble extracts obtained from all

0

1

2

3

4

5

6

7

8

9

10 11 48

60 56

46

Oil Variation Clay Variation

52

44 42

48

40 44

38

40

36

36

34

32

32

28

30 28 25

30

35

40

45

50

55

60

65

70

Conjugated Linseed Oil In Samples (wt %) Fig. 1.

75

Soluble contents of Nano-composites (wt %)

Soluble contents of Nano-composites (wt %)

Clay Contents (%) -1

other samples (CLin30-CLin70). The peak at 2.8 ppm is due to the methylene (CH2) protons present in between the two unsaturated C]C double bonds of the fatty acid chain. The appearance of a similar peak in the DVB is due to the presence of methylene protons in the ethylvinylbenzene, which is present to the extent of about 20% of the DVB. The peaks for the vinylic (C]C–H) protons of the linseed oil, AcA and DVB are present at 5.1–6.8 ppm. The peaks at 4.1– 4.5 ppm in the soluble extract (CLin30 to CLin70) (sample CLin50 is shown in Fig. 2) and in conjugated linseed oil are due to the methylene protons (CH2) of the glyceride unit. This is a characteristic peak for the linseed oil. It is used in calculating the oil content in the soluble extract of polymeric material. The aromatic protons of the DVB and the oligomeric portion of the material are observed between 7.1 and 7.9 ppm. These aromatic peaks are distinctive and are used to calculate the DVB content in the soluble extracts. However, the solvent (CDCl3) peak, which appears in the same region at 7.26 ppm, has been excluded from all calculations. The peak at 11.9 ppm in acrylic acid is due to the –OH of the carboxylic group present in the acid, which shifted downwards to 9.8 ppm in the polymeric samples. The acrylic acid generally exists in dimeric form due to presence of intermolecular hydrogen bonding (Scheme 1) and, when it is polymerized, the dimeric form becomes non-existent. The cleavage of intermolecular hydrogen bonding leads to the shifting downwards of the signal. This peak is a characteristic peak of acrylic acid. The solvent removed from the soluble portion by vacuum evaporation is free from any oligomers and the peak is shown in Fig. 2. The peak is the same as for pure solvent. The contents of conjugated linseed oil, acrylic acid and divinylbenzene (wt%) for different polymeric samples are reported in Table 2. The content of linseed oil (wt%) in the soluble extract varies from 95 to 98% with varying oil content and the content of the acrylic-DVB component varies from 2 to 5% at fixed nano-filler content (5%). The contents of conjugated linseed oil in the soluble extract and insoluble portion increases with an increase in the oil

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

919

Conjugated Linseed Oil

CL in 50-AcA 40-DVB 10 (CTABMONT 5%)

Solvent for extraction and collected solvent on extraction

Divinylbenzene

Acrylic Acid

12

11

10

9

8

7

6

5

4

3

2

1

0

Fig. 2.

H

O H2C

O CH

CH O

H

O

Acrylic Acid

Intermolecular Hydrogen Bonding Cleavage

O

2 H2C

CH

OH Acrylic Acid Scheme 1.

CH2

ppm

920

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

content of the samples. At varying filler content from 0 to 10%, the content of conjugated linseed oil varies from 93 to 96% and the content of acrylic-DVB components varies from 4 to 7%. The pristine polymer sample shows a maximum soluble oil content (43 wt%) and the sample with 2.5% filler show a minimum soluble oil content (28 wt%). 4.3. FTIR analysis of linseed nano-composites 4.3.1. Organophilic modification of montmorillonite The montmorillonite clay was modified by using two organic modifiers, cetyl trimethyl ammonium bromide (CTAB) and hexadecyl ammonium bromide (HDAB). The modification was studied by FTIR (Fig. 3). The appearance of new peaks at 2927, 2855 and 1460 cm1 indicates the occurrence of an exchange reaction. The peaks at 2927 and 2855 cm1 correspond to the C–H stretching vibrations of CH2 groups and the peak at 1460 cm1 corresponds to C–H deformation vibration of CH2 groups. These peaks indicate that the CTAB or HDAB cations are exchanged with the sodium ions of montmorillonite clay. Fig. 3 shows the characteristic peaks of both montmorillonite clay and the organic surfactant modified clay (CTAB–MONT and HDAB–MONT). The peak at 1013 cm1 can be ascribed to the Si–O–Si stretching vibrations and peaks between 552 and 728 cm1 can be ascribed to the stretching and bending vibrations of Si–O [33]. These peaks also appear in the nano-composite of conjugated linseed oil-acrylic aciddivinylbenzene in Figs. 4 and 5, indicating the existence of the silicate network. 4.3.2. Quantification of grafted oil and montmorillonite clay The quantitative analysis of a component in solution can be successfully carried out provided that there is a suitable band in the spectrum of the component of interest. A simple solid mixture can be easily analyzed quantitatively, but a component in a complex mixture presents special problems. The mixture of conjugated linseed oil, acrylic acid and divinylbenzene is a complex mixture. The selection of characteristic peaks can solve the complexity of quantification. To quantify the unknown amount of linseed

Fig. 4.

oil grafted to AcA–DVB copolymer and the percentage of grafting, four absorbance peaks at 1744, 1711, 1530 and 694 cm1 were selected [28–30]. These four peaks are at 1744 cm1 for ester linkage in the oil, at 1711 cm1 for the carbonyl stretch in the acrylic acid, at 1530 cm1 for aromatic –C]C– linkage in divinylbenzene and at 694 cm1 for Si–O, Si–O–Al stretching vibrations [34]. The selected absorbance peaks are shown in Figs. 4 and 5. The regression calibration curves of various contents (wt%) against absorbance are obtained from the absorbance of samples at different peaks (Fig. 6). The data from the calibration curve is used to calculate the linseed oil content (wt%) in the insoluble portion and are reported in Table 3. It is observed that the grafted conjugated linseed oil content increases with an increase in the oil content from 2.12 to 18.67% at fixed clay content (5%). The content of grafted conjugated linseed oil decreases with an increase in the clay content from 2.5 to 10% in the nano-composite samples with fixed monomer content. The sample with 2.5% clay has the highest, and the pristine polymer sample

0.8

Absorbance (A. U.)

0.7 0.6

552 cm

0.5 0.4

-1

-1

728 cm

2927 cm

0.3

1013 cm

-1

-1

MONT

2855 cm

-1

1460 cm

0.2

HDAB-MONT

0.1

CTAB-MONT

-1

0.0 3000

2500

2000

1500

1000

500

Wavenumber (cm-1) Fig. 3.

Fig. 5.

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

a

1.6

0.165

Nano-composite Samples (at Fixed Clay contents) Y = 0.106 + (5.147)X

0.150

2

R = 0.9916; SD = 0.0922 N = 5; P < 0.914 x 10

1.4

Absorbance (A. U.)

1.8

-3

A1744/A1711+1540+742) Linear Fit

1.0 0.8

Sample with Montmorillonite Clay

0.135 0.120 1035 cm-1

0.105 0.090 0.075 0.060

-1

813 cm 526 cm-1

0.045

0.6

0.030

0.4 0.4

0.6

0.8

1.0

1.2

1.4

1.6

Sample without Montmorillonite Clay

2000

1.8

1500

1000

500

Wavenumber (cm-1) 1.2

b

1.1 1.0

Fig. 7.

Nano-composite samples with variable clay contents (2.5-10 %) Y = 0.441 + (3.689)X 2 R = 0.9298; SD = 0.0917 N = 4; P < 0.070

A1744/A1711+1540+742) Linear Fit

0.9 0.8 0.7 0.6 0.82

0.84

0.86

0.88

0.90

0.92

0.94

0.96

CLin/(AcA+DVB+MONT) (wt/wt) Fig. 6.

shows a minimum, grafted linseed oil content. The addition of nano-clay at 2.5% level results in the increase of barrier properties of the polymer matrix and it is difficult for a liquid to diffuse through it. The FTIR spectrum for the pristine polymer and montmorillonite containing polymer is shown in Fig. 7. It is observed that the polymer sample with montmorillonite shows characteristic peaks for the Si–O–Si and Si–O stretching vibrations, which are absent in the pristine polymer. The peak at 1035 cm1 can be ascribed to the Si–O–Si stretching vibrations and peaks between 526 and 813 cm1 can be ascribed to the stretching and bending vibrations of Si–O [34]. The clay

Table 3 The grafted linseed oil contents and clay contents in the insoluble portion of the polymers nano-composites calculated through FTIR spectroscopy Sample ID

Linseed oil contents (wt%)

Clay contents (wt%)

CLin30 CLin40 CLin50 CLin60 CLin70 CTABMONT2.5 CTABMONT7.5 CTABMONT10 HDABMONT2.5 MONT0

2.12 8.84 14.85 18.67 17.46 22.57 12.24 10.94 8.40 6.84

3.37 3.69 4.04 4.38 4.44 2.18 6.23 8.25 1.98 0

contents in the insoluble portion of the nano-composite are also estimated as embedded clay in the polymer matrix. This indicates that the clay is also extracted in the soluble portion during soxhlet extraction. The calibration curve for clay content is obtained by plotting absorbance ratio as a function of the relation clay/polymer ratio at the initial level (Fig. 8). The contents of clay entrenched in the polymer matrix are reported in Table 3. At a fixed montmorillonite content of 5%, the clay entrenched in the matrix increases from 3.37 to 4.44% with an increase in the linseed oil content. For fixed monomer content and a variation in montmorillonite content from 2.5 to 10%, the calculated (embedded) montmorillonite content increases. The gap between the original and the calculated amount goes on increasing with increasing content of clay in the samples. It is observed that the gap is a minimum at 2.5%, indicating maximum exfoliation and having less loss during extraction. The linseed oil grafted to the polymer is calculated from 1 H NMR and FTIR spectroscopic analysis and the variation of contents of grafted linseed oil with the linseed oil content in the samples is plotted in Fig. 9. It is observed

Absorbance ratio (A742 / A1744+1711+1540)

Absorbance Ratio (A1744/A1711+1540+742)

1.2

921

0.16

Samples with Clay Variation 2.5 - 10 %

0.14

Y = -0.026 + (1.912)X 2 R = 0.9916; SD = 0.0098 N = 4; P < 0.0098

0.12 0.10

A742 / A1744+1711+1540 Linear Fit

0.08 0.06 0.04 0.02 0.00 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11

MONT/CLin+AcA+DVB (wt./wt.) Fig. 8.

922

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

a

20

5.0

With variation in linseed oil

18

1H-NMR

a 4.8

Results

FTIR Results

16

4.6

14

4.4

12 4.2

10

Grafted Linseed Oil (wt %)

6 4 2 0 25

30

35

40

45

50

55

60

65

70

Linseed Oil (wt %) 24 23

With variation in clay contents

b

22

1

21

FTIR Results

H-NMR Results

20 19

Clay Contents in Nano-composites (wt %)

4.0

8

Change in clay contents with change in oil %

3.8 3.6

Original Clay Contents Clay Contents through FTIR

3.4 25

30

35

40

45

50

55

60

65

70

Linseed Oil Contents (wt %) 10 9

b

Change in clay with change in clay % Original Clay Contents (wt %)

8

Clay Contents through FTIR (wt %)

7

18 6

17 16

5

15 14

4

13 3

12 11

2

10 2

3

4

5

6

7

8

9

10

11

Clay Contents (wt %)

2

3

4

5

6

7

8

9

10

11

Clay Variation (wt %)

Fig. 9.

Fig. 10.

from Fig. 9a that the content of grafted linseed oil increases linearly with increase in the oil content from 30 to 60%, and then shows a decrease for the sample with 70% linseed oil content. For an increase in clay content from 2.5 to 10%, the content of grafted linseed oil decreases. The grafted linseed oil calculated from 1H NMR results corroborate with the results obtained from FTIR analysis. The nano-composite formation is confirmed by the Si–O and Si–O–Si stretching vibrations. Fig. 10 shows the change in the clay content calculated from FTIR to the original clay content with variation in linseed oil content (Fig. 10a) and with variation in nano-filler content (Fig. 10b). In Fig. 10a, the change in the clay content (which as per composition is fixed at 4.76%) is plotted against the variation in the linseed oil content from 30 to 70%. It is observed that the increase in oil content from 30 to 70% results in an increase in the embedded clay (wt%) from 3.37 to 4.44%. The sample with minimum linseed oil and maximum acrylic acid is supposed to show maximum exfoliation. Linseed oil is less reactive as compared to acrylic acid and divinylbenzene. Hence, it is expected that the embedded clay will be

a maximum for the sample with minimum linseed oil content. However, the results are exactly opposite to the behavior expected. This is only possible if the rate of polymerization increases with the increase in oil content. The above mentioned findings have been confirmed during the heating of pure conjugated linseed oil and a mixture of modified montmorillonite clay with conjugated linseed oil at 100  C. During the same period of heating (thermal polymerization), it has been observed that increase in viscosity is much higher in the case of the nano-clay filled conjugated linseed oil compared to only conjugated linseed oil. This indicates that the rate of thermal polymerization increases considerably due to the presence of nano-filler. The nano-fillers are sodium and magnesium silicates [Mþy(Al2  y Mgy)(Si4)O10(OH)2$nH2O], and the cations generally help during the drying of linseed oil [35–37]. Fig. 10b shows the change in embedded clay (%) with the variation in original clay content (%). In Fig. 10b, the polymer composition is same for all the samples, only clay content is changed from 2.44 to 9.09%. It is observed that

V. Sharma et al. / Polymer Testing 27 (2008) 916–923

the increase in clay content from 2.44 to 9.09% results in widening of the gap between original and calculated values (from FTIR). This suggests that the loss of filler is a minimum (0.26%) for the sample containing 2.5% clay due to better exfoliation. 5. Conclusions Nano-composites from conjugated linseed oil, acrylic acid and divinylbenzene using organophilic montmorillonite have been prepared by thermal polymerization. The nanocomposites were successfully studied by using 1H NMR and FTIR spectroscopy. The organophilic modification of the montmorillonite clay was done by using CTAB and HDAB surfactants and confirmed by FTIR analysis. Soxhlet extraction was used to separate the soluble and insoluble part of the nano-composites. The solubility of samples through soxhlet extraction ranges from 28 to 55% with varying linseed oil content (30–70%) and 28 to 43% for the samples with varying montmorillonite clay content (0 to 10%). The soluble extract and insoluble portion were used for further study of the nano-composites. The linseed oil grafted to the nanocomposites was quantified by 1H NMR as well as by FTIR spectroscopy. The results from FTIR and 1H NMR corroborate each other. The content of grafted linseed oil in the nanocomposites ranges from 2 to 19% with varying oil content (30–70%) and 7 to 22% with varying clay content (0–10%). The clay embedded in the polymer matrix was also calculated from FTIR studies. The clay embedded to the polymer matrix ranges from 3 to 5% with varying oil content (30–70%) and 0 to 8% with varying clay content (0 to 10%). References [1] R. Gangopadhyay, A. De, Chem. Mater. 12 (2000) 608–622. [2] S.S. Ray, M. Biswas, Mater. Res. Bull. 33 (1998) 533–538. [3] F.R. Costa, U. Wagenknecht, G. Heinrich, Polym. Degrad. Stab. 92 (2007) 1813–1823. [4] S.D. Burnside, E.P. Giannelis, Chem. Mater. 7 (1995) 1597–1600. [5] S.H. Hwang, S.W. Paeng, J.Y. Kim, W. Huh, S.W. Lee, Polym. Bull. 49 (2003) 329–335. [6] H. Zhao, S.D. Argoti, B.P. Farrell, D.A. Shipp, J. Polym. Sci., Part A: Polym. Chem. 42 (2004) 916–924. [7] H.K. Fu, C.F. Huang, J.M. Huang, F.C. Chang, Polymer 49 (2008) 1305–1311.

923

[8] N.A. Hocine, P. Mederic, T. Aubry, Polymer Test. 27 (2008) 330–339. [9] P. Maiti, C.A. Batt, E.P. Giannelis, Biomacromolecules 8 (2007) 3393– 3400. [10] M. Alexandre, P. Dubois, Mater. Sci. Eng. 28 (2000) 1–63. [11] Y. Kojima, A. Usuki, M. Kawasumi, A. Okada, Y. Fukushima, T. Karauchi, O. Kamigaito, J. Mater. Res. 6 (1993) 1185–1189. [12] J.W. Gilman, C.L. Jackson, A.B. Morgan, R. Harris Jr., E. Manias, E.P. Giannelis, M. Wuthenow, D. Hilton, S.H. Phillips, Chem. Mater. 12 (2000) 1866–1873. [13] E.P. Giannelis, R. Krishnamoorti, E. Manias, Adv. Polym. Sci. 138 (1999) 107–147. [14] I. Hackman, L. Hollaway, Durability and mechanical properties of polymer-layered silicate nanocomposites, in: Chen, Teng (Eds.), Proceedings of the International Symposium on Bond Behaviour of FRP in Structures (BBFS 2005), 2005, pp. 525–530. [15] S.S. Ray, M. Okamoto, Prog. Polym. Sci. 28 (2003) 1539–1641. [16] T. Shichi, K. Takagi, J. Photochem. Photobiol. C Photochem. Rev. 1 (2000) 113–130. [17] G. Brindley, G. Brown (Eds.), Crystal Structure of Clay Minerals and Their X-ray Identification, Miner Soc London, 1980, pp. 227–232. [18] A.J.F. De Carvalho, A.A.S. Curvelo, J.A.M. Agnelli, Carbohydr. Polym. 45 (2001) 189–194. [19] P. Viville, R. Lazzaroni, E. Pollet, M. Alexandre, P. Dubois, G. Borcia, J.J. Pireaux, Langmuir 19 (2003) 9425–9433. [20] A. Vermogen, K. Masenelli-Varlot, R. Seguela, J. Duchet-Rumeau, S. Boucard, P. Prele, Macromolecules 38 (2005) 9661–9669. [21] J.L. Koenig, Spectroscopy of Polymers, second ed. Elsevier, 1999. [22] N. Eidelman, C.G. Simon Jr., J. Res. Natl. Inst. Stand. Technol 109 (2004) 219–231. [23] N. Everall, P.R. Griffiths, J.M. Chalmers, Vibrational Spectroscopy of Polymers: Principles and Practice, Wiley, 2007. [24] E. Boccaleri, A. Arrais, A. Frache, W. Gianelli, P. Fino, G. Camino, Mater. Sci. Eng. B 131 (2006) 72–82. [25] B.C. Smith, Multiple Components II: Chemometric Methods and Factor Analysis in Quantitative Spectroscopy: Theory and Practice, Academic Press, California, USA, 2002. [26] P.M. Henrichs, J.M. Hewitt, L.J. Schwartz, D.B. Bailey, J. Polym. Sci., Part A: Polym. Chem. 20 (1982) 775–782. [27] H.N. Cheng, Macromolecules 30 (1997) 4117–4125. [28] S.M.S. Jamaludin, M.R. Nor Azlan, M.Y.A. Fuad, Z.A.M. Ishak, U.S. Ishiaku, Polymer Test. 19 (2000) 635–642. [29] L.B. Canto, L.A. Pessan, Polymer Test. 21 (2002) 35–38. [30] P. Zhang, J. He, X. Zhou, Polymer Test. 27 (2008) 153–157. [31] S. Chakraborty, S. Bandyopadhyay, S.C. Ameta, R. Mukhopadhyay, A.S. Deuri, Polymer Test. 26 (2007) 38–41. [32] G.M.M. Sadeghi, J. Morshedian, M. Barikani, Polymer Test. 22 (2003) 165–168 [33] J.W. Kim, M.H. Noh, H.J. Choi, D.C. Lee, M.S. Jhon, Polymer 41 (2000) 1229–1231. [34] P.S. Nayak, B.K. Singh, Bull. Mater. Sci. 30 (2007) 235–238. [35] W.L. Evans, P.E. Marling, S.E. Lower, Ind. Eng. Chem. Res. 19 (1927) 640–641. [36] G.L. Clark, H.L. Tschentke, Ind. Eng. Chem. Res. 21 (1929) 621–627. [37] A.J. Currier, I.H. Kagarise, Ind. Eng. Chem. Res. 29 (1937) 467–469.