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Home , Polystyrene, Vinyl chloride

International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: [email protected] Volume 3, Issue 5, May 2014 ISSN 2319 - 4847

Optical properties of Poly ()/ blends

Asrar Abdulmunem Saeed & Mohammed Zorah Hassan

Mustansiriyah University- College of Science, Baghdad, Iraq

Abstract Poly (Vinyl chloride) (PVC)/polystyrene (PS) blends with different ratios were prepared by solvent from tetrahydrofuran (THF). The absorption spectra of polyvinylchloride / polystyrene blends at different concentrations (PVC %, 75% PVC/25% PS, 50% PVC / 50%PS, 25% PVC/75% PS, % PS) showed absorption changes in the wavelength range, which depends on the type, and on the concentration of the polymer blends. It was found that 50 % PVC / 50 % PS ratio from these showed higher absorption values in comparison with the other blends. The absorption spectra has been recorded in the wave length range (200 –1100) nm. The absorption coefficients (α), the extinction coefficient (K), (n) have been evaluated.

Key words: optical properties, PVC/PS blend, optical constants.

1- Introduction Polymer blends are a mixture of chemically different polymers or with no covalent bonding between them. Polymer blends are classified as three types, namely, homologous, miscible and immiscible blends. Chemically identical polymers with different molecular masses constitute homologous polymer lends. Miscible polymer blends exhibit single phase behavior and immiscible polymer blends exhibit two or more phases at all compositions and temperatures. Preparation of polymer blends has been received considerable importance in the recent past owing to the shorter time and lower cost of the product development than those of a new polymer [1]. The performance of a polymeric material can be improved by selection of suitable ingredients and their ratios. Polymer blending imparts certain new characteristics leading to the formation of new materials with enhanced physical, chemical and mechanical properties [2, 3]. Blending of two polymers having different properties is usually producing a new polymeric material. These new polymeric material mat possess the properties of both the polymers. The properties of polymer blends such as toughness, strength, etc have close relationships with their internal micro phase morphology [4-6]. Polyvinylchloride has been found to form an immiscible blend with polystyrene. Miscibility is not a prerequisite for blends applications; it is an easy way to design a new polymeric material. Polystyrene is a well-known amorphous polymer with good thermal and radiation resistant properties. Polystyrene is available with a wide range of formulations. The styrenic part may impart the properties like toughening, flame resistance and solvent resistance. Commercially available polystyrene is mostly a tactic type and amorphous in nature. The use of polystyrene is limited because of its susceptibility to degradation from UV radiation, chemical attack from aromatic, and chlorinated may also cause problem in application areas. is one of the most important commercial polymers that have wide range of applications [7]. Polyvinylchloride is a linear, , substantially amorphous polymer, with a huge commercial interest, due to the accessibility to basic raw materials and to its properties. Polymeric materials have attracted the scientific and technological researchers, because of their wide applications. Deshmukh, et al reported the optical transmission and UV-VIS absorption spectra in wavelength of (450-1000)nm with different concentration of polyanline doped PVC-PMMA thin films, the absorption coefficient( ), optical energy gap (Eopt), refractive index(n) and optical constant had been evaluated. The effects of doping percentage of polyaniline on these parameters had been discussed and nonlinear behaviors for all the parameters were investigated [8]. Burghate et al [9] studied the optical properties of PVC-PMMA polymer blends. Joshi et al [10] study the polyblend of polyvinyl chloride (PVC) and polystyrene (PS) in the weight ratio 5:1 using (1.25 g) of PVC and (0.25 g) of PS by casting method. Polyaniline (PANI) has been used as dopant and with (0.5%, 1.0%, 2.0% and 2.5%) of the total weight of the polymers. On the basis of optical absorbance and transmittance measurements at normal incidence of light in the wavelength range (500-1000) nm, the absorption coefficient, optical energy gap, refractive index, optical dielectric constant and ratio of carrier concentration to the effective mass was reported for polyaniline doped PVC-PS blend. It was found that the behavior of all the optical parameters found to be nonlinear. V. Sangawar and N. Mohari[11] study the electrical, thermal and optical band gap of polypyrrole filled PVC:PMMA thin films, they prepared polypyrrole by chemical oxidative method from pyrrole using ammonium per sulfate as oxidant and p- sulphonic as a dopant. G. Patel et al [12] study PVC/PMMA polymer blends were characterized by Fourier Transform Infrared Spectroscopy (FTIR), UV-VIS spectroscopy and mechanical analysis. The changes in mechanical properties are reflected by the changes in the IR spectrum. The mechanical properties of such poly blends revealed a substantial increase in Young modulus and ultimate tensile strength after initial drop at 10% of PMMA.

Volume 3, Issue 5, May 2014 Page 61

International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: [email protected] Volume 3, Issue 5, May 2014 ISSN 2319 - 4847

Optical properties such as the absorption coefficient, optical energy gap were calculated. The effects of different blending percentage on these parameters have been discussed and their results are co-related with IR study. In the present work, PVC/PS blends were prepared with different weight ratios to investigate the optical properties for this blend.

2- Experimental work Commercial grades of PVC and PS were purchased from Modern Scientific Company, Coimbatore and used as received. A series of polymer blends of PVC and PS were prepared from the common solvent tetrahydrofuran(THF) as follows Polymer solutions were prepared by dissolving PVC/PS in various weight ratios (100/0, 75/25, 50/50, 25/75, 0/100 w/w) in THF with thickness about(0.09, 0.095, 0.09, 0.1, 0.085) mm. The solutions were mixed at room temperature and stirred for 4 hours. The solutions were then poured in to the glass plates and THF was slowly evaporated under ambient conditions to form transparent films.

3- Results and Discussion The optical constants are very important because they describe the optical behavior of the materials. The absorption coefficient of the material is very strong function of photon energy and band gap energy. The variation of absorption with wave length of the incident light were recorded by using (UV-VIS. Spectrometer, T70-80) in the wavelength optical range (200 – 1100)nm for . Figure (1) show the absorption spectrum which reveals a strong absorption probability below (250 – 290)nm for (PVC % , 75% PVC/25%PS, 50% PVC / 50%PS , 25% PVC/75% PS, % PS ) respectively .There is sudden decrease in the absorption values observed above the limits. For (50% PVC/ 50% PS) the decrease was even slower. The (50% PVC / 50% PS ) blend showed high absorption than the other blends for polymer blend (PVC/PS) and all the films showed the same behavior but the absorption was decrease at %PS.

Figure. (1): UV/Visible absorption spectroscopy of (PVC/PS) with wave length at different concentration

The sudden raises in absorption spectrum called absorption edge that can be used to determine the optical band gap from calculate the absorption coefficient (α) [13, 14],  = (2.303×A)/t (1) Where A: is the absorption of the material. t: is the sample's thickness (cm). Figure (2) show the relationship of the absorption coefficient with wave length of different weight percentages of PVC/PS blends, it show light absorption edge for PVC, while it became less for PS.

Figure. (2): UV/Visible absorption coefficient of (PVC/PS) with wavelength at different concentration

The refractive index (n) and extinction coefficient (K) were calculated from the following equations, (eqs. (2 and 3)), and plotted in figs. (3 and 4)[13, 15]:

Volume 3, Issue 5, May 2014 Page 62

International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: [email protected] Volume 3, Issue 5, May 2014 ISSN 2319 - 4847

4RR 1 n  (2) R 12  K 2 R 1 R: is the optical reflectance.

Figure (3) shows the variation of refractive index (n) as a function of wave length. In order to compare our results of refractive index for PS with the published data, which were calculated at 600 nm. The value of (n) was found to be (1.85) for thickness (20 µm), while Ahmed et al [16], obtained the value of (n= 2.13) with thickness (100 µm) and Papanu et al [17] obtained (n= 1.48) with thickness (1µm) deposited on silicon wafer. The difference in (n) value is attributed to the different in thickness.

Figure (3): variation of refractive index for (PVC/PS) blend with wave length.

Figure (4) shows the variation of extinction coefficient ( ) with wave length (λ). The blend (50% PVC / 50% PS) concentration has the highest value of (K) and it was displaced toward the long wavelength.

Figure (4): variation of extinction coefficient for (PVC/PS) blend with wavelength.

Table (1) : The parameters of optical constants for polymer blend (PVC / PS)

-1 -4 Polymer. system α (cm ) n 10 ×K PVC 172 2.01 3

75% PS/25% PVC 213 1.17 4.9

50% PS/50% PVC 186 1.82 4.3

25% PS/75% PVC 187 1.8 4.18 PS 240 1.3 5.9

4- Conclusion 1- Strong absorption clear between (200 – 290) nm. 2- 50% PVC / 50% PS blend showed the best optical properties. 3- The absorption coefficient, extinction coefficient, refractive index for (50% PVC / 50% PS) show significant change from samples in compared with other blend samples. Volume 3, Issue 5, May 2014 Page 63

International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: [email protected] Volume 3, Issue 5, May 2014 ISSN 2319 - 4847

References [1] D.H. Baik, G.L. Kim, Y.H. Park, Y. Lee and Y. Son, Effect of polymer blending on the electrical conductivity of polypyrrole/copolyesters composite films, Polymer Bulletin,Vol. 41, pp. 713-719, (1998). [2] A.Z. Aroguz and B.M. Baysal, Thermal, Mechanical and Morphological Characterization Studies of Poly (2, 6- dimethyl1, 4-phenylene oxide) Blends with Polystyrene and Brominated Polystyrene, J. App. Polym. Sci., Vol. 75, pp. 225 – 231, (2000). [3] R. Chakrabarti, M. Das and D. Chakraborty, Physical, Mechanical, and Thermal Properties of PVC/PMMA Blends in Relation to Their Morphologies, J. App. Polym. Sci., Vol. 93, pp. 2721-2730, (2004). [4] P. Raghu, C.K. Nere and R.N. Gagtap, Effect of -Isoprene-Styrene, Styrene-Butadiene-Styrene, and Styrene- Butadiene-Rubber on the Mechanical, Thermal, Rheological and Morphological Properties of /Polystyrene Blends, J. App. Polym. Sci., Vol. 88, pp. 266-277, (2003). [5] M.Y. Gelfer, H.H. Song, L. Liu, B.S. Hsiaol, B. Chul, M.Rafailovich, and V.Zaitsev, Effects of Organoclays on Morphology and Thermal and Rheological Properties of Polystyrene and Poly (methyl methacrylate) Blends, J. Polym. Sci. Part B: Polym. Physics, Vol. 41, pp. 44–54, (2003). [6] S. Shabbir, S. Zulfiqar, I. Lieberwirth, A. Kausar and M.I. Sarwar, Compatibilizing Effect of Functionalized Polystyrene Blends: A Study of Morphology, Thermal and Mechanical Properties, Surf. Interface Anal., Vol. 40, pp. 906–913, (2008). [7] Q. Wang, B.k. Storn, Polymer Testing, Vol. 24, pp. 290, (2005). [8] SH. Deshmukh, DK. Burghate, SN. Shilaskar, GN. Chaudhari and P. Deshmukh, Indian Journal of Pure and Applied Physics, Vol. 46, pp. 344-348, (2008). [9] D. Burghate, A. Bobade, L. Joshi, V.P. Akhare, P.T. Deshmukh, M.S. Deshmukh and S. Shilaskar, J. Polym. Mater. Vol. 26, (2009). [10] L.Joshi, M. Deshmukh, P. Deshmukh, D. Burghate and S. Shilaskar, J. Polym. Mater. Vol. 28, pp. 93-100, (2011). [11] V. Sangawar and N. Moharil, Chemical Science Transactions, Vol. 1, pp. 447-455, (2012). [12] G. Patel, M. Sureshkumar and P. Patel, Kerala, (), AIP Conf. Proc. 1391, 645, (2011). [13] J. Pankov, Optical Processes in Semiconductors. New Jersey: Prentice-Hall, (1971). [14] N.F. Mott, E.A. Davis, Electronic Process in Non-Crystalline Materials (second edition). UK: Clarendon Press Oxford, (1979). [15] M. Balkanski, Optical Properties of , Vol. 2, Amsterdam, New York. Oxford, (1992). [16] A. Ahmed, a. Awatif and N. Majied, Eng. And Technology, Vol. 25, pp.558, (2007). [17] J. Popanu, D. Hess, D. Soane and A.T. Bell, Polym. Sci., Vol.39, pp. 303, (1990).

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