**5.3 Fourier Transform Infrared (FTIR) studies**

The FTIR spectra and description of vibration modes of pure PVC, pure Li2B4O7, SPC1, PC and SPC5 are shown in Figures 7(a)–(e) and Table 2, respectively. Comparing SPC1 with pure PVC, there are 10 new peaks have been formed. All of these new peaks are the characteristic bonds of Li2B4O7. Five new peaks have been detected in the wavenumber range of 1200 cm-1–700 cm-1. These peaks are assigned as B–O(B) stretching mode of BO4 tetrahedral shape of Li2B4O7 at 710 cm-1, 815 cm-1, 905 cm-1, 1034 cm-1 and 1120 cm-1. In contrast, for B–O(B) stretching mode of BO3 triangle shape, Li2B4O7 portrays two characteristic peaks at 1246 cm-1 and 1376 cm-1. However, only one peak is observed at 1253 cm-1 for SPC1. This indicates the interaction between PVC and Li2B4O7 and further reveals the decoupling of Li+ from the B–O(B) coordinative bonds. Four new peaks at 451 cm-1, 504 cm-1, 565 cm-1 and 670 cm-1 are designated as O–B–O deformation mode of BO4 tetrahedral in Li2B4O7. All the vibration modes exhibit peak shifting, except the weak peak at 1331 cm-1 which is denoted as CH2 deformation of PVC.

As shown in Figure 7(a), the transmittance peaks at 616 cm-1 and 969 cm-1 are corresponding to cis and trans C–H wagging modes, respectively. Upon addition of Li2B4O7, these peaks are shifted towards higher wavenumber to 637 cm-1 and 973 cm-1, respectively. Apart from that, they exhibit changes in shape. For cis wagging mode, it has been changed from weak peak to shoulder peak, whereas a medium peak has been changed to a broad band for trans wagging mode. A sharp peak is observed at 1067 cm-1 in Figure 7(a), which designated as C– H rocking mode of PVC. However, it turns to a broad band with inclusion of Li2B4O7 and manifests a downward shift to 1062 cm-1. The peak at 833 which corresponds to C–Cl

Characterization of High Molecular Weight Poly(vinyl chloride) –

we proposed as above.

verifies the establishment of polymer complex.

associated in the polymer matrix.

Lithium Tetraborate Electrolyte Plasticized by Propylene Carbonate 181

mode of PVC at 825 cm-1 , and ring stretching and breathing modes of PC at 850 cm-1. As explained in section 5.1, we propose that the hydrogen atom from methyl group in PC would break the O–Li coordination bond through hydrogen bonding. Thus, the dissociated Li+ would interact with the chloride anion of the C–Cl interactive bond in PVC and ultimately form CH–Cl–Li linkage. A broad band is observed at 1062 cm-1 in SPC1 spectrum. However, this C–H rocking mode of PVC has been changed to weak shoulder peak at 1074 cm-1 with adulteration of PC. The effect of PC is also observed for the shoulder peak at 1120 cm-1. As tabulated in Table 2, this peak is assigned as B–O(B) stretching mode of BO4 tetrahedral of Li2B4O7. Nevertheless, a medium sharp peak is attained at 1117 cm-1. The change in shape is due to the merging of this stretching mode with C–O stretching mode of PC as a medium sharp peak is obtained at 1118 cm-1, as shown in Figure 7(d). This interaction further proves the mechanism of complexation that

SPC1 exemplifies two weak peaks at 1331 cm-1 and 1426 cm-1. The first peak is designated as CH2 deformation of PVC, whereas the C–H stretching mode of CH2 group of PVC is for latter peak. Upon inclusion of PC, these two peaks are still appearing in the spectrum. The first peak is shifted upward to 1332 cm-1, whereas the latter peak remains unchanged. Two more new weak peaks have been discovered in this band. These peaks are the B–O(B) stretching mode of BO3 triangle of Li2B4O7 and C–H symmetric deformation mode of PC at 1351 cm-1 and 1388 cm-1, respectively. Moreover, the change in intensity is one of the aspects to determine the complexation of this plasticized–polymer electrolyte. The peak shifting of B–O(B) stretching mode of BO3 triangle shape in Li2B4O7 at 1253 cm-1 still remain the same. However, its peak intensity is slightly declined, from 28% to 21%, in transmittance mode, as illustrated in Figure 8. In contrast, the increase in peak intensity is obtained at high wavenumber range of 3000 cm-1–2900 cm-1. Only two peaks are observed in this range. Both of these peaks are denoted as CH3 asymmetric stretching mode of PVC and shifted to 2912 cm-1 (from 2910 cm-1) and 2975 cm-1 (from 2971 cm-1). In term of intensity, the peaks are gradually increased. For the first peak, it rises up around 7%, from 5% to 12%, in transmittance mode. The peak intensity of latter peak enhances around 10%, from 7% to 17%, in transmittance mode. This reveals the interaction between PVC and PC and further

Some of the characteristic peaks of PC are not be found in the SPC5 spectrum compared to PC spectrum. These peaks include CH2 bending deformational mode of CH3 group of PC, in plane CH2 scissoring mode of PC and the combinations of CH2 rocking and ring breathing mode of PC at 1460 cm-1, 1482 cm-1 and 1555 cm-1, respectively. In PC spectrum, an intrinsic vibrational band of the C=O symmetric stretching mode is located at ∼1800 cm−1. This strong and broad band splits into two components (at 1787 cm−1 and 1900 cm−1). The overtone is produced at 1900 cm−1 as a consequence of Fermi resonance of the C=O stretching mode with the ring breathing mode that lies at ∼950 cm−1. However, this overtone of PC is not being observed in SPC5 spectrum. This disappearance of characteristic divulges the interaction between PC and polymer system. The changes in position, changes in shape, changes in intensity, formation of new peaks and disappearance of peak infers the interaction between PVC, Li2B4O7 and PC. Therefore, it can be concluded that PC is

stretching mode of PVC also shifted to 825 cm-1 upon impregnation of lithium salt. Similarly, C–H stretching mode of CH2 group which is located at 1434 cm-1 for pure PVC spectrum also exhibits downward shift to 1420 cm-1. This discloses the interactions between C–H, C–Cl and Li+. It suggests that the Li+ would be dissociated from O–Li interactive bond by forming hydrogen bonds to hydrogen atom from C–H group in PVC. Hence, these mobile Li+ would re–interact with chloride anions in PVC as chloride anions have three electron lone pairs. The ionic hopping mechanism is eventually generated. The vibrational modes of characteristic peaks not only undergo the changes in shift and shape, but they also demonstrate the change in intensity. An apparent proof has been observed in the wavenumber region of 3000 cm-1–2800 cm-1. Two sharp peaks are located at 2867 cm-1 and 2979 cm-1, and are denoted as CH3 asymmetric stretching mode of PVC. The first transmittance peak is found to be shifted to higher wavenumber of 2910 cm-1, meanwhile it has been moved to 2971 cm-1, for latter peak. Upon the addition of Li2B4O7, the intensity of both peaks is greatly reduced by comparing Figure 7(a) with 7(c). Regarding to the changes in peak intensity, changes in shape, changes in shift, formation of new peaks and disappearance of the peak, it reflects the establishment of polymer–salt complex.

In order to investigate the complexation between PC and polymer matrix, SPC5 is further examined as it achieves the maximum ionic conductivity. Comparing SPC1 with SPC5, seven new peaks have been formed. These peaks are denoted as ring deformation of PC, ring stretching and breathing modes of PC, C–O stretching mode of PC, B–O(B) stretching mode of BO3 triangle shape of Li2B4O7, C–H symmetric deformation mode of PC and C=O symmetric stretching mode of PC at 795 cm-1, 959 cm-1, 1054 cm-1 and 1187 cm-1, 1351 cm-1, 1388 cm-1 and 1794 cm-1, respectively. Upon PC loadings, some of the characteristic peaks are disappeared. These peaks are the weak peaks in PC at 950 cm-1 and 910 cm-1, and the shoulder peak of SPC1 at 1035 cm-1. The characteristic peaks at 446 cm-1, 503 cm-1, 566 cm-1 and 668 cm-1 are designated as O–B–O deformation mode of BO4 tetrahedral in Li2B4O7. The weak peak at 446 cm-1 is originated from the medium sharp peak at 451 cm-1 in SPC1 spectrum. In term of intensity, this characteristic peak is reduced around 18%, from 23% to 5%, in transmittance mode. For the weak peaks at 503 cm-1 and 566 cm-1, they show signs of changes in shape. It has been changed to broad band and slightly shifted from 504 cm-1 for the first peak. On the other hand, the latter peak displays a somewhat upward shift from 565 cm-1 and changed to shoulder peak. An oppose result is obtained for the peak at 702 cm-1, which assigned as B–O(B) stretching mode of BO4 tetrahedral in Li2B4O7. This peak illustrates downward shift from 710 cm-1 to 702 cm-1 and the change in shape, from shoulder peak to weak peak.

Noticeable change in shape is observed in the wavenumber range of 700 cm-1–600 cm-1. A weak peak at 668 cm-1 with a shoulder peak at 637 cm-1 has been changed to two weak peaks at 670 cm-1 and 636 cm-1, respectively, by doping PC into the polymer complex. As aforementioned, the peak at 670 cm-1 is the characteristic peak of O–B–O deformation mode of BO4 tetrahedral, whereas cis C–H wagging mode in PVC is the assignment for the latter peak. Therefore, it implies the interaction between PVC, Li2B4O7 and PC. There is another evidence to prove the complexation between PVC, Li2B4O7 and PC at 830 cm-1. Two shoulder peaks have been changed to a broad band. This arises from the combination of B–O(B) stretching mode of BO4 tetrahedral shape of Li2B4O7 at 815 cm-1, C–Cl stretching

stretching mode of PVC also shifted to 825 cm-1 upon impregnation of lithium salt. Similarly, C–H stretching mode of CH2 group which is located at 1434 cm-1 for pure PVC spectrum also exhibits downward shift to 1420 cm-1. This discloses the interactions between C–H, C–Cl and Li+. It suggests that the Li+ would be dissociated from O–Li interactive bond by forming hydrogen bonds to hydrogen atom from C–H group in PVC. Hence, these mobile Li+ would re–interact with chloride anions in PVC as chloride anions have three electron lone pairs. The ionic hopping mechanism is eventually generated. The vibrational modes of characteristic peaks not only undergo the changes in shift and shape, but they also demonstrate the change in intensity. An apparent proof has been observed in the wavenumber region of 3000 cm-1–2800 cm-1. Two sharp peaks are located at 2867 cm-1 and 2979 cm-1, and are denoted as CH3 asymmetric stretching mode of PVC. The first transmittance peak is found to be shifted to higher wavenumber of 2910 cm-1, meanwhile it has been moved to 2971 cm-1, for latter peak. Upon the addition of Li2B4O7, the intensity of both peaks is greatly reduced by comparing Figure 7(a) with 7(c). Regarding to the changes in peak intensity, changes in shape, changes in shift, formation of new peaks and

disappearance of the peak, it reflects the establishment of polymer–salt complex.

peak to weak peak.

In order to investigate the complexation between PC and polymer matrix, SPC5 is further examined as it achieves the maximum ionic conductivity. Comparing SPC1 with SPC5, seven new peaks have been formed. These peaks are denoted as ring deformation of PC, ring stretching and breathing modes of PC, C–O stretching mode of PC, B–O(B) stretching mode of BO3 triangle shape of Li2B4O7, C–H symmetric deformation mode of PC and C=O symmetric stretching mode of PC at 795 cm-1, 959 cm-1, 1054 cm-1 and 1187 cm-1, 1351 cm-1, 1388 cm-1 and 1794 cm-1, respectively. Upon PC loadings, some of the characteristic peaks are disappeared. These peaks are the weak peaks in PC at 950 cm-1 and 910 cm-1, and the shoulder peak of SPC1 at 1035 cm-1. The characteristic peaks at 446 cm-1, 503 cm-1, 566 cm-1 and 668 cm-1 are designated as O–B–O deformation mode of BO4 tetrahedral in Li2B4O7. The weak peak at 446 cm-1 is originated from the medium sharp peak at 451 cm-1 in SPC1 spectrum. In term of intensity, this characteristic peak is reduced around 18%, from 23% to 5%, in transmittance mode. For the weak peaks at 503 cm-1 and 566 cm-1, they show signs of changes in shape. It has been changed to broad band and slightly shifted from 504 cm-1 for the first peak. On the other hand, the latter peak displays a somewhat upward shift from 565 cm-1 and changed to shoulder peak. An oppose result is obtained for the peak at 702 cm-1, which assigned as B–O(B) stretching mode of BO4 tetrahedral in Li2B4O7. This peak illustrates downward shift from 710 cm-1 to 702 cm-1 and the change in shape, from shoulder

Noticeable change in shape is observed in the wavenumber range of 700 cm-1–600 cm-1. A weak peak at 668 cm-1 with a shoulder peak at 637 cm-1 has been changed to two weak peaks at 670 cm-1 and 636 cm-1, respectively, by doping PC into the polymer complex. As aforementioned, the peak at 670 cm-1 is the characteristic peak of O–B–O deformation mode of BO4 tetrahedral, whereas cis C–H wagging mode in PVC is the assignment for the latter peak. Therefore, it implies the interaction between PVC, Li2B4O7 and PC. There is another evidence to prove the complexation between PVC, Li2B4O7 and PC at 830 cm-1. Two shoulder peaks have been changed to a broad band. This arises from the combination of B–O(B) stretching mode of BO4 tetrahedral shape of Li2B4O7 at 815 cm-1, C–Cl stretching mode of PVC at 825 cm-1 , and ring stretching and breathing modes of PC at 850 cm-1. As explained in section 5.1, we propose that the hydrogen atom from methyl group in PC would break the O–Li coordination bond through hydrogen bonding. Thus, the dissociated Li+ would interact with the chloride anion of the C–Cl interactive bond in PVC and ultimately form CH–Cl–Li linkage. A broad band is observed at 1062 cm-1 in SPC1 spectrum. However, this C–H rocking mode of PVC has been changed to weak shoulder peak at 1074 cm-1 with adulteration of PC. The effect of PC is also observed for the shoulder peak at 1120 cm-1. As tabulated in Table 2, this peak is assigned as B–O(B) stretching mode of BO4 tetrahedral of Li2B4O7. Nevertheless, a medium sharp peak is attained at 1117 cm-1. The change in shape is due to the merging of this stretching mode with C–O stretching mode of PC as a medium sharp peak is obtained at 1118 cm-1, as shown in Figure 7(d). This interaction further proves the mechanism of complexation that we proposed as above.

SPC1 exemplifies two weak peaks at 1331 cm-1 and 1426 cm-1. The first peak is designated as CH2 deformation of PVC, whereas the C–H stretching mode of CH2 group of PVC is for latter peak. Upon inclusion of PC, these two peaks are still appearing in the spectrum. The first peak is shifted upward to 1332 cm-1, whereas the latter peak remains unchanged. Two more new weak peaks have been discovered in this band. These peaks are the B–O(B) stretching mode of BO3 triangle of Li2B4O7 and C–H symmetric deformation mode of PC at 1351 cm-1 and 1388 cm-1, respectively. Moreover, the change in intensity is one of the aspects to determine the complexation of this plasticized–polymer electrolyte. The peak shifting of B–O(B) stretching mode of BO3 triangle shape in Li2B4O7 at 1253 cm-1 still remain the same. However, its peak intensity is slightly declined, from 28% to 21%, in transmittance mode, as illustrated in Figure 8. In contrast, the increase in peak intensity is obtained at high wavenumber range of 3000 cm-1–2900 cm-1. Only two peaks are observed in this range. Both of these peaks are denoted as CH3 asymmetric stretching mode of PVC and shifted to 2912 cm-1 (from 2910 cm-1) and 2975 cm-1 (from 2971 cm-1). In term of intensity, the peaks are gradually increased. For the first peak, it rises up around 7%, from 5% to 12%, in transmittance mode. The peak intensity of latter peak enhances around 10%, from 7% to 17%, in transmittance mode. This reveals the interaction between PVC and PC and further verifies the establishment of polymer complex.

Some of the characteristic peaks of PC are not be found in the SPC5 spectrum compared to PC spectrum. These peaks include CH2 bending deformational mode of CH3 group of PC, in plane CH2 scissoring mode of PC and the combinations of CH2 rocking and ring breathing mode of PC at 1460 cm-1, 1482 cm-1 and 1555 cm-1, respectively. In PC spectrum, an intrinsic vibrational band of the C=O symmetric stretching mode is located at ∼1800 cm−1. This strong and broad band splits into two components (at 1787 cm−1 and 1900 cm−1). The overtone is produced at 1900 cm−1 as a consequence of Fermi resonance of the C=O stretching mode with the ring breathing mode that lies at ∼950 cm−1. However, this overtone of PC is not being observed in SPC5 spectrum. This disappearance of characteristic divulges the interaction between PC and polymer system. The changes in position, changes in shape, changes in intensity, formation of new peaks and disappearance of peak infers the interaction between PVC, Li2B4O7 and PC. Therefore, it can be concluded that PC is associated in the polymer matrix.

Characterization of High Molecular Weight Poly(vinyl chloride) –

**Description of vibration modes**

O–B–O deformation mode of BO4 tetrahedral of Li2B4O7

B–O(B) stretching mode of BO4 tetrahedral shape of Li2B4O7

Ring stretching and breathing

Trans C–H wagging mode of

B–O(B) stretching mode of BO3 triangle shape of Li2B4O7

C–H symmetric deformation

C–H stretching mode of CH2

CH2 bending deformation mode

In plane CH2 scissoring mode of

Combinations of CH2 rocking

C=O symmetric stretching

CH3 asymmetric stretching

Overtone of PC (2×ring breathing mode of PC

at 950 cm-1)

mode of PVC

C–O stretching mode of PC 1051, 1118

modes of PC

Lithium Tetraborate Electrolyte Plasticized by Propylene Carbonate 183

Cis C–H wagging mode in PVC 616 637 636 Rajendran et al.,

Ring deformation of PC <sup>780</sup> – <sup>795</sup>Deepa et al.,

C–Cl stretching mode of PVC 833 825 830 Li et al., 2006a

PVC <sup>969</sup> 973 Disappear Achari et al.,

C–H rocking mode of PVC 1067 1062 1074 Achari et al.,

CH2 deformation of PVC 1331 <sup>1331</sup> <sup>1332</sup>Rajendran et al.,

mode of PC <sup>1390</sup> – <sup>1388</sup>Sharma and

group of PVC <sup>1434</sup> 1426 1426 Rajendran et al.,

of CH3 group of PC <sup>1460</sup> – Not appear Deepa et al.,

PC <sup>1482</sup> – Not appear Deepa et al.,

and ring breathing mode of PC <sup>1555</sup> – Not appear Deepa et al.,

mode of PC <sup>1787</sup> – <sup>1794</sup>Sharma and

Table 2. Assignments of vibrational modes of pure PVC, pure Li2B4O7, PC, SPC1 and SPC5.

2867 and 2979

452, 504, 565 and 669

> 706, 821, 898, 1030 and 1117

850, 910, 950

and 1183

1246 and

**Wavenumber (cm-1)**

**Li2B4O7/PC SPC1 SPC5** 

451, 504, 565 and 670

> 710, 815, 905, 1035 and 1120

<sup>1376</sup> <sup>1253</sup>1253 and

**References PVC/** 

and 955 – 959 Deepa et al.,

<sup>1900</sup> – Not appear Sharma and

2912 and 2975

2910 and 2971

446, 503,

702 and

1054, 1117 and 1187

566 and 668 Ge et al., 2007

<sup>1117</sup>Ge et al., 2007

2008a

2004

2004

2007

Deepa et al., 2004

2007

2000b

Sekhon, 2007

2008a

2004

2004

2004

Sekhon, 2007

Sekhon, 2007

Rajendran et al., 2000b

<sup>1351</sup>Ge et al., 2007

Fig. 7. The FTIR spectra of (a) pure PVC, (b) pure Li2B4O7, (c) SPC1, (d) PC and (e) SPC5.

Fig. 7. The FTIR spectra of (a) pure PVC, (b) pure Li2B4O7, (c) SPC1, (d) PC and (e) SPC5.


Table 2. Assignments of vibrational modes of pure PVC, pure Li2B4O7, PC, SPC1 and SPC5.

Characterization of High Molecular Weight Poly(vinyl chloride) –

Lithium Tetraborate Electrolyte Plasticized by Propylene Carbonate 185

around 45 % of its weight with around 43% residual mass, from 230 °C to 390 °C. In contrast, for SPC7, it is around 29% with 37% residual mass, starting from 238 °C to 388 °C. SPC9 starts to decompose at 239 °C and exemplifies a modest weight loss of 37% at 389 °C, with residual weight of 28%. Among the plasticized–polymer electrolytes, SPC5 portrays the lowest total weight loss of 57%. SPC5 is still a promising candidate as polymer electrolyte although its total weight loss is higher than SPC1. SPC5 exhibits excellent thermal stability

as its stability is up to 230 °C, whereby the normal working range is 40–70 °C.

Fig. 9. Thermogravimetric analysis of pure PVC, SPC1, SPC5, SPC7 and SPC9.

that SPC5 exhibits good thermal stability in comparison with SPC7 and SPC9.

The PVC–Li2B4O7–PC plasticized–polymer system has been prepared and investigated in this project. Upon addition of 20wt% of PC (or designated as SPC5), the highest conductivity of 4.12×10-6 Scm-1 is achieved at ambient temperature. Plasticizer plays a fundamental role to weaken the interaction within the polymer matrix and hence increases the ionic conductivity with a flexible polymer backbone. The polymer electrolytes obey the Arrhenius behavior and indicate the ionic hopping mechanism, as proven in temperature dependence–ionic conductivity studies. In addition, FTIR studies help us to confirm the complexation of PVC–Li2B4O7–PC system by determining the, changes in intensity, changes in shape and changes in shift, appearance and disappearance the peaks. Moreover, the thermal stability of the polymer films is contradictory to the PC mass loadings. By analyzing the TGA thermograms, it divulges

0 100 200 300 400

Pure PVC SPC1 SPC5 SPC7 SPC9

**Temperature (°C)**

**6. Conclusion** 

0

20

31.33% 37.49%

28.11%

43.38% 51.34%

40

60

**Weight (%)**

80

100

120

Fig. 8. The change in intensity of B–O(B) stretching mode of BO3 triangle shape of Li2B4O7 at 1253 cm-1 for (a) SPC1 and (b) SPC5.

#### **5.4 Thermogravimetric analysis (TGA)**

Figure 9 describes the thermogravimetric curves of SPC1, SPC5, SPC7 and SPC9. Two distinct stages have been observed in the temperature regime. The first weight loss is credited to the evaporation of residual THF solvent and dehydration of entrapped moisture (Ramesh et al., 2010). A moderate mass loss is initially observed. Pure PVC and SPC1 elucidate around 6% and 1% of mass losses at 159 °C and 150 °C, respectively. Even though the adulteration of PC increases the weight loss, but it also boosts up the decomposition temperature. As observed, the drop in weight is further increased with increasing the PC concentration. Around 11%, 31% and 32% of weight losses are attained for SPC5, SPC7 and SPC9 at 160 °C, 169 °C and 180 °C, respectively. After complete the dehydration, a stable weight is followed up in the thermal range.

Beyond this stable range, the weight of polymer complexes is drastically reduced in this stage. Dehydrochlorination process is the main contributor for this weight loss. At high temperature, the degrading products such as Cl free radicals are produced initially upon combustion. For further propagation, these free radicals would react with the methyl group of PC and hence break up the interactive bond, leading to the dehydrochlorination mechanism. The HCl cleavage would produce allyl chloride. Then, this allyl chloride favors the unzipping process and results in polyene linkage. This unzipping reaction induces many degradation reactions such as random chain scission reaction, depolymerization, inter– molecular transfer reaction and intra-molecular transfer reaction whereby dimers, trimers and oligomers are produced as well as polymer fragments. As a result, the monomer and oligomers which chemi–adsorbed onto the polymer matrix is volatilized in this region (Ramesh et al, 2011a). Pure PVC has mass loss of 63%, starting from 250 °C to 389 °C, with a residual mass of 31%. As can been seen, the weight losses have been improved by doping of Li2B4O7 and PC. SPC1 delineates the mass loss of 46%, from 230 °C to 390 °C, with residual mass of around 51 %. The effect of PC onto the weight loss is further observed. SPC5 has lost around 45 % of its weight with around 43% residual mass, from 230 °C to 390 °C. In contrast, for SPC7, it is around 29% with 37% residual mass, starting from 238 °C to 388 °C. SPC9 starts to decompose at 239 °C and exemplifies a modest weight loss of 37% at 389 °C, with residual weight of 28%. Among the plasticized–polymer electrolytes, SPC5 portrays the lowest total weight loss of 57%. SPC5 is still a promising candidate as polymer electrolyte although its total weight loss is higher than SPC1. SPC5 exhibits excellent thermal stability as its stability is up to 230 °C, whereby the normal working range is 40–70 °C.

Fig. 9. Thermogravimetric analysis of pure PVC, SPC1, SPC5, SPC7 and SPC9.
