Investigation the Effect of Thermal Agent on Physical Properties of PVC-PVA Blended

In this study, the optical characteristics of polyvinyl chloride(PVC), polyvinyl alcohol (PVA) and binary PVA - PVC blend films at various concentrations PVA75% + PVC25%, PVA50% + PVC50%


Introduction
With new polymer development, composites, and blends it became necessary to modify thermal, mechanical, optical, and electrical characteristics to get the desired features 1 .A polymer blend is a Published Online First: February, 2024 https://doi.org/10.21123/bsj.2024.8992P-ISSN: 2078-8665 -E-ISSN: 2411-7986 Baghdad Science Journal composition 3 .Poly (vinyl chloride) PVC is a rigid, hard substance at room temperature 5 .It is reasonably dense and has a low softening point.The chlorine atom boosts interchain attraction, resulting in an increase in the polymer's stiffness and hardness.In the realm of plastics, PVC's rigid shape, which may be extruded into pipe, conduit, or sheet, is important.It can be utilized in place of rubber in low-voltage cables and domestic wiring since it is flexible.With major applications ranging from high-volume construction-related products to straightforward electric wire insulation and coatings, this polymer could be called the most frequently used plastic substance [6][7] .Due to its numerous significant characteristics, polyvinyl alcohol (PVA) is a crucial polymer for the pharmaceutical and biomedical industries.It was applied to food, industrial, commercial, and medicinal products [8][9] .A linear polymer with a carbon-chain backbone and hydroxyl groups joined to methane carbonate is polyvinyl alcohol.The hydroxyl groups can act as hydrogen bond sources and facilitate the production of polymers.PVA is not a material that is found in nature.The main component utilized in the manufacturing of polyvinyl alcohol is vinyl acetate monomer 10 .The studies of ultraviolet and visible light spectroscopy to as certain how substances absorb, transmit, and emit these wavelengths of light can be used to calculate the coefficient of absorption α from the absorbance (A) [11][12][13] : Where (t) the thickness of thin film.Many researchers studied the physical properties of blend and composite of PVC and PVA and they get good results.Due to its cheap production cost, PVA has recently been the subject of extensive study, which has led to a variety of industrial uses.As a result, this work attempts to employ a PVA-PVC polymer blending approach that can enhance the physical properties of the materials generated.Ghuzlan S.  16 have studied the optical properties of polyvinyl alcohol (PVA)and doped with CuO and Fe2Cl3 and they get good results.Zainab A. Al-Ramadhan and Itab Fadhil Hussein 17 have studied the optical parameters of poly(vinyl chloride)(PVC) and PVC doped with Zn(etx)2.The addition of the dopant was shown to have an impact on optical parameters including the absorption coefficient, refraction index (n), and extinction coefficient (K).The effect of temperatures on the optical properties of (PMMA-PVC-PS) blend was studied by Ali N. Sabbar, Karar M. Talib and Hassan T. Badh, they obtained that the energy gap was reduced by applied temperatures 18 .In this work the effect of different temperatures 25, 120 and 140 °C for 1 hour on the optical characteristics of binary blend films of PVC and PVA at various concentrations PVA75% + PVC25%, PVA50% + PVC50%, and PVA25% + PVC75% were examined.

Materials and Methods
Polyvinyl alcohol (PVA) processed by the company Central Drug House (CDH)(India) with a molecular weight 14000 g/mole, polyvinyl chloride (PVC) processed by the company SABIC (Saudi) with a molecular weight 6000 g/mole and dimethylformamide (DMF) processed by Thomas Baker (India) used in this work.By using the casting method, PVC, PVA and binary blended with varying concentrations PVA75%+PVC25%, PVA50%+PVC50%, and PVA25%+PVC75% were obtained 19 .PVC and PVA films are made by dissolving 0.4 grams of each polymer in dimethylformamide (DMF) solvent using a magnetic stirrer at 50 0 C for 4 hours, casting the solution into a glass dish, and allowing it to dry for 2 days at room temperature.To make binary blended in various concentrations PVA75%+PVC25%, PVA50%+PVC50%, and

Results and Discussion
The absorption spectra for PVA, PVC, and the binary PVA-PVC blends at different concentrations are shown in Fig. 1.PVA exhibits a small absorbance peak at 275 nm with an absorbance 0.2477.This absorption peak might be related to π →π* electronic transition, this is agreed with reference 20 , which is followed by a significant increase in absorption at 250 nm.Whereas the pure PVC film's absorption spectrum exhibits a broad spectrum.The absorbance value at 240 nm abruptly rises in PVC.Binary PVA-PVC blends have a greater absorption compared to PVA and PVC pure polymers.The absorption spectra of binary PVA-PVC blends increased with increased the amount of PVA.The increase in absorbance in the blend due to overlap between chains of polymers leads to increased charge carriers 21 .The increased absorption and the best ratio of the blend are evident with PVA 75%+ PVC25%.The spectrum transmittance of PVA, PVC, and binary PVA-PVC blend films is shown in Fig. 2. The transmission in the binary mixture of PVA and PVC is lower than it is for PVA and PVC that are pure polymers.When the amount of the PVA in binary PVA-PVC blends increased, the transmission values decreased.With an increase in temperature, the weak PVA peaks in the binary blend became more absorbent.Increases in the absorbance in polymer blend with increased temperatures agree with reference 18 .
Fig. 6 depicts the spectrum of transmittance for a binary blend with various concentrations PVA75%+PVC25%, PVA50%+PVC50%, and PVA25%+PVC75% as a function of temperature at 120,140 °C for 1 hour.As the temperature was raised, the binary blend's transmission dropped off.The absorption coefficient can be obtained from Eq. 1. Fig. 7 illustrates the absorption coefficient for PVA, PVC, and a binary combination of both at various concentrations.The binary blend absorption coefficient is better than pure polymer because of increase in absorption due to the charge carried increased 21 .When the amount of the PVA in binary PVA-PVC blends increased, the absorption coefficient is increased.Electronic transitions are classified as direct transitions when the absorption coefficient is greater than 10 4 cm -1 or as indirect transitions when it is less than 10 4 cm -1 12-22 .In this paper, the indirect nature of the electrical transitions is expected.Fig. 9 illustrates the absorption coefficient for a binary blend of PVA75%+PVC25%, PVA50%+PVC50%, and PVA25%+PVC75% at various temperatures.After applying temperatures, the binary blend's absorption coefficient rose, this is agreed with reference 18 .PVA, PVC, and binary mixed exhibit indirect electronic transitions both before and after applied temperatures.The optical energy gap in indirect electronic transitions can be calculated via plot (α h ν) 1/2 to the h ν in high absorption ranges then extrapolating the region of linear to (α h ν) =0 12 .Fig. 10 and Table 1 show the optical energy gap of PVA, PVC, and their binary blend with different concentrations.
As the concentration of polyvinyl alcohol increased, the energy gap of binary PVA-PVC blend decreased.Fig. 11 and Table 1 illustrate the impact of temperature at 120,140 °C for 1 hour on the energy gap of PVA and PVC films.When the temperature was raised, in PVA the energy gap shrunk.The energy gap in PVC was slightly altered by the applied temperature.Fig. 12

Figure 1 .
Figure 1.Spectrum of absorption for PVA, PVC and binary blend PVA-PVC.

Fig. 3 Figure 3 .
Fig.3illustrates the temperature effect at 120,140 °C for 1 hour on the spectrum of absorption of PVA and PVC films.With a rise in temperature, the absorbance of the PVA's faint peak rose.PVC's absorbance changes slightly as the temperature rises.

Figure 4 .Fig. 5
Figure 4. Spectrum of transmittance at different temperatures for: A=PVA and B=PVC.Fig.5 depicts the spectrum of absorption of a binary mix with various concentrations PVA75%+PVC25%, PVA50%+PVC50%, and PVA25%+PVC75% after one hour at 120,140 °C.With an increase in temperature, the weak PVA peaks in the binary blend became more absorbent.Increases in the absorbance in polymer blend with increased temperatures agree with reference18 .

Figure 7 .
Figure 7. Absorption coefficient for PVA, PVC and binary blend PVA-PVC.The absorption coefficient of PVA and PVC after undergo temperature at 120,140 °C for 1 hour is shown in the Fig.8.In PVA, the absorption coefficient increase after applied temperature while the absorption coefficient of PVC slight changes after applied temperature.

Figure 8 .
Figure 8. Absorption coefficient at different temperatures for: A=PVA and B=PVC.

Figure 11 .
Figure 11.Energy gap at different temperatures for: A=PVA and B=PVC.

Table 1 . The effect of temperature on energy gap for PVA, PVC and their binary blend
and Table1display the energy gap for a PVC blend led to improve physical properties (absorption and absorption coefficient) and the best ratio of the blend is evident with PVA 75%+ PVC25%.We suggest a new field of binary