Pure and Applied Chemistry Novel Copolymers of

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Journal of Macromolecular Science, Part A: Pure and Applied Chemistry Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lmsa20

Novel Copolymers of Difluoro Ring-substituted 2Phenyl-1,1-dicyanoethylenes with 4-Fluorostyrene: Synthesis, Structure and Dielectric Study a

a

b

b

Salima Atlas , Mustapha Raihane , Gregory B. Kharas , Peter G. Hendrickson , Hamid a

c

Kaddami , Mourad Arous & Ali Kallel

c

a

Laboratory of Organometallic and Macromolecular Chemistry-Composites Materials, Faculty of Sciences and Technologies , Cadi-Ayyad University , Marrakech , Morocco b

Chemistry Department , DePaul University , Chicago , Illinois

c

Laboratoire des Matériaux Composites, Céramiques et Polymères, Faculté des Sciences de Sfax , Sfax , Tunisia Published online: 24 Oct 2012.

To cite this article: Salima Atlas , Mustapha Raihane , Gregory B. Kharas , Peter G. Hendrickson , Hamid Kaddami , Mourad Arous & Ali Kallel (2012) Novel Copolymers of Difluoro Ring-substituted 2-Phenyl-1,1-dicyanoethylenes with 4-Fluorostyrene: Synthesis, Structure and Dielectric Study, Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, 49:12, 997-1010, DOI: 10.1080/10601325.2012.728453 To link to this article: http://dx.doi.org/10.1080/10601325.2012.728453

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Journal of Macromolecular Science, Part A: Pure and Applied Chemistry (2012) 49, 997–1010 C Taylor & Francis Group, LLC Copyright
ISSN: 1060-1325 print / 1520-5738 online DOI: 10.1080/10601325.2012.728453

Novel Copolymers of Difluoro Ring-substituted 2-Phenyl-1,1-dicyanoethylenes with 4-Fluorostyrene: Synthesis, Structure and Dielectric Study SALIMA ATLAS1, MUSTAPHA RAIHANE1, GREGORY B. KHARAS2∗, PETER G. HENDRICKSON2, HAMID KADDAMI1, MOURAD AROUS3, and ALI KALLEL3 1

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Laboratory of Organometallic and Macromolecular Chemistry-Composites Materials, Faculty of Sciences and Technologies, Cadi-Ayyad University, Marrakech, Morocco 2 Chemistry Department, DePaul University, Chicago, Illinois 3 Laboratoire des Mat´eriaux Composites, C´eramiques et Polym`eres, Facult´e des Sciences de Sfax, Sfax, Tunisia Received, Accepted June 2012

Copolymerization of fluorine ring-substituted 2-phenyl-1,1-dicyanoethenes, RC6 H3 CH C(CN)2 (R is 2,3-F,F, 2,4-F,F, 2,5-F,F, 2,6F,F, and 4-CF3 ) with 4-fluorostyrene were prepared in the presence of a radical initiator (ABCN) at 70◦ C. The composition of the copolymers was calculated from nitrogen analysis, and the copolymers were characterized by IR, 1H and 13C-NMR, GPC, DSC, and TGA. The monomer reactivity ratios for 4-fluorostyrene (M1 ), r1 = 0.6 and 2-(2,4-difluorophenyl)-1,1-dicyanoethene (M2 ), r2 = 0 were determined from Fineman-Ross plot. The order of relative reactivity (1/r1 ) for difluoro-substituted monomers is 2,4-F,F (0.31) > 2,3-F,F (0.25) > 2,5-F,F (0.22) > 2,6-F,F (0.10). DSC curves showed that the copolymers were amorphous with high T g in comparison with that poly(4-fluorostyrene) indicating a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer units. From the thermogravimetric analysis, the copolymers began to degrade in the range 214–260◦ C. The copolymer of 4-fluorostyrene and 2-(2,4-difluorophenyl)-1,1-dicyanoethene and poly(4-fluorostyrene) were dielectrically characterized in the range 25–200◦ C. The dominating relaxation process detected in both materials was the α-relaxation, associated with the dynamic glass transition. The relationship polarity-permittivity was discussed. Keywords: Trisubstituted ethylenes, radical copolymerization, 4-fluorostyrene copolymers, dielectric properties

1 Introduction Trisubstituted ethylenes (TSE, CHR1 = CR2R3) continue to attract attention of polymer chemists as reactive comonomers and models for mechanistic studies. It was shown that electrophilic tri- and tetrasubstituted olefins are particularly useful in delineating the transition from radical chemistry to ionic chemistry (1). Previous studies showed that TSE containing substituent larger than fluorine exhibit no tendency to undergo polymerization via double bonds. This is due to kinetic consideration superimposed on the thermodynamic factor responsible for the difficulty with which 1,1 and 1,2-disubstituted ethylenes polymerize. Radical copolymerization provides the most general method of overcoming problems encountered in homopolymerization of TSE monomers (2). This approach has been successful

∗

Address correspondence to: Gregory B. Kharas, Chemistry Department, DePaul University, IL 60614-3214. Fax: 773-325-7421; Email: [email protected]

in preparing copolymers from electrophilic TSE monomers having double bonds substituted with halo, cyano, and carbonyl groups and electron-rich monosubstituted ethylenes such as styrene, N-vinylcarbazole, and vinyl acetate (3, 4). These copolymers showed a tendency toward the formation of alternating copolymers which can be explained by the formation of donor-acceptor complexes (5). Ring–unsubstituted 2-phenyl-1,1-dicyanoethylene was copolymerized with styrene (6,7), vinyl ethers (8,9), methyl methacrylate (10) and N-vinyl-2-pyrrolidone (11). In relation to electric applications of cyano polymers, the piezoelectric activity of the amorphous with high T g of an alternating copolymers of 1,1-dicyanoethylene (vinylidene cyanide) (VCN) and vinyl acetate (VAc) was described by Miyata et al. (12). The dielectric behavior of the poly(VCNalt-VAc) has been studied by Furukawa et al. (13), the most important finding in this investigation is the very large dielectric strength or unusual large relaxation strength above its T g in non-crystalline copolymer. Unlike fluoropolymers, a mesophase glass structure has been proposed for this copolymer allowing cooperative effects in relation to

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dipolar motions of CN groups around the glass transition temperature (T g = 178◦ C). This copolymer has impedance similar to that of the human body and has been suggested for medical applications as an ultrasonic transducer (14). Alpha relaxation phenomena have been characterized around to T g temperatures in the dielectric study of TSE copolymers of vinylidene methyl cyanide with 4fluorostyrene and 4-chlorostyrene (15). The low values of dielectric increment, ε were explained by the steric effect of the bulky aromatic groups (16). Montheard et al. (17) have studied the radical copolymerization of VCN with two styrenic comonomers bearing a fluorinated chain in the para position, leading to alternating copolymers. Random copolymers of VCN with 1,1-difluoro-2,2-dichloroethylene and 1,2- difluoro-1,2-dichloroethylene (18) have been reported. The synthesis of TSE copolymer based on methyl vinylidene cyanide and 2,2,2-trifluoroethyl methacrylate has been reported (19) and recently its dielectric behavior has been investigated (20). In recent study, we have presented the synthesis and characterization of a novel copolymer of vinylidene cyanide (VCN) and 2,2,2-trifluoroethyl methacrylate (MATRIF) (21). High-resolution 1H and 13 C-NMR spectra were used to study the microstructure of the copolymer suggesting alternating tendency in this copolymerization. The dynamic dielectric behavior of the poly(VCN-co-MATRIF) copolymer was also investigated, this copolymer exhibited a dynamic scenario with four relaxation processes, two above T g , merging at low temperatures, and two below T g . Addition of VCN unit increased the dielectric constant as well as the value of T g (22). Recently, the radical copolymerization of some ring substituted of 2-phenyl-1,1-dicyanoethylenes with 4fluorostyrene has been reported (23–27). In continuation of our studies of cyano- and fluorinesubstituted polymers it was of interest to prepare and characterize novel copolymers of fluorine ring-substituted 2-phenyl-1,1-dicyanoethenes, RC6 H3 CH C(CN)2 (R is 2,3-F,F, 2,4-F,F, 2,5-F,F, 2,6-F,F, and 4-CF3 ) with 4fluorostyrene.

the copolymers were measured with TA (Thermal Analysis, Inc.) Model Q10 differential scanning calorimeter (DSC). The thermal scans were performed in a 25 to 200◦ C range at a heating rate of 10◦ C/min. T g was taken as a midpoint of a straight line between the inflection of the peak’s onset and endpoint. The thermal stability of the copolymers was measured by thermogravimetric analyzer TA Model Q50 from ambient temperature to 800◦ C at 20◦ C/min. The molecular weights of the polymers were determined relative to polystyrene standards in THF solutions with sample concentrations 0.8% (wt/vol) by gel permeation chromatography (GPC) using a Altech 426 pump at an elution rate of 1.0 mL/min; TSK–GEL G4000HHR column at 25◦ C, and Viscotek 302 and Viscotek UV 2501 detector. 1H- and 13CNMR spectra were obtained on 10–25% (w/v) monomer or polymer solutions in CDCl3 at ambient temperature using a Bruker Avance 300 MHz spectrometer. Elemental analyses were performed by Quantitative Technologies (NJ). Dielectric relaxation spectroscopy (DRS) measurements were performed on thin rectangular strips (dimensions of about 10 × 10 × 0.5 mm3). The films were metalized using aluminum to prevent the specimen from losing its dimensional integrity when heating and to improve the contact with the electrodes. Then, the sample was placed between two gold parallel plate electrodes. The parallel plate sensors were used to evaluate bulk dielectric properties and to track molecular relaxations. Dielectric determinations of the complex permittivity ε∗ (ε∗ = ε (f) − jε (f)), the real part (apparent permittivity) ε , the imaginary part (loss factor) ε and the dissipation factor tan δ (tan δ = ε /ε ) were performed using a Novocontrol Dielectric Alpha Analyzer allowing measurements over the temperature ranging from −150◦ C to 300◦ C and a frequency interval from 0.001 to 10 Mhz. The temperature was automatically controlled by using the Novocontrol Quatro Cryosystem temperature controller. The dielectric measurements were performed by isochronal runs with fixed frequencies and ramping temperatures from ambient to 200◦ C, and then decreasing it with a heating rate of 2◦ C/min under a nitrogen atmosphere.

2 Experimental

2.3 Monomer Synthesis

2.1 Materials 2,3-difluoro-, 2,4-difluoro-, 2,5-difluoro-, 2,6-difluoro-, 4trifluoromethylbenzaldehydes, piperidine, 4-fluorostyrene (4FST), 1,1 -azobis(cyclohexanecarbonitrile) (ABCN), chloroform, THF, and toluene supplied from Aldrich Chemical Co., were used as received. 2.2 General Procedures Infrared spectra of the TSE monomers (NaCl plates) and polymers (KBr pellets) were determined with a Nicolet Avatar 360 FT-IR spectrometer. The melting points of the monomers and the glass transition temperatures (T g ) of

The TSE monomers were synthesized by Knoevenagel condensation (28) of an appropriate ring-substituted benzaldehyde with malononitrile, catalyzed by base, piperidine (Sch. 1). The synthesis procedure and characterization of 2,4-difluoro, 2,5-difluoro (29), and 2,6-difluorophenylsubstituted TSE (30) was described earlier. In a typical synthesis, equimolar amounts of malononitrile and an appropriate benzaldehyde were mixed with 2 mL of DMF in an Erlenmeyer flask. A few drops of piperidine were added with stirring. The crystalline product of the reaction was isolated by filtration, purified by crystallization from 2-propanol, and dried until constant weight in a vacuum oven.

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Novel Copolymers of 4-Fluorostyrene 3.2 Copolymerization

Sch. 1. Monomer synthesis (where R = 2,3-F,F; 2,4-F,F; 2,5-F,F; 2,6-F,F; 4-CF3 ).

The copolymers were prepared at 4FST/TSE = 1/1 (mol) the monomer feed using 4 wt% of ABCN dissolved in toluene and heated at 70◦ C (Sch. 2). After 48 h, the mixture was cooled to room temperature, and precipitated dropwise in methanol. The yields of copolymerization were ranging between 50 and 70%. The composition of the copolymers was determined based on the nitrogen content.

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3.3 Characterization 2.3.1 2-(2,3-difluorophenyl)-1,1-dicyanoethylene Yield: 84%; mp 139◦ C; 1H-NMR δ 8.1, 7.6, 7.0 (m, PhH), 8.0 (s, CH ); 13C-NMR δ 163 (CH ), 166, 163, 161, 150, 130, (Ph), 113 (C≡N), 85 (C ); IR 3031 (w, C-H phenyl), 2226 (m, C≡N), 1651(m, C C). Anal. Calcd. for C10H4F2N2: C, 63.17; H, 2.12; N, 14.73; Found: C, 63.36; H, 1.79; N, 14.47. 2.3.2 2-(4-trifuoromethylphenyl)-1,1-dicyanoethylene Yield: 82%; mp 114◦ C; 1H-NMR δ 7.8, 7.1, 7.0 (m, PhH), 8.2 (s, CH ); 13C-NMR δ 158 (CH ), 146, 130, 128, 126 (Ph), 115, 114 (C≡N), 117 (C ); IR 3029 (w, C-H phenyl), 2227 (m, C≡N), 1647(m, C C). Anal. Calcd. for C11H5F3N2: C, 59.47; H, 2.27; N, 12.61; Found: C, 58.21; H, 2.11; N, 12.33.

3 Results and Discussion 3.1 Homopolymerization These TSE monomers are unable to homopolymerize which is associated with steric difficulties encountered in homopolymerization of 1,1 and 1,2-disubstituted ethylene (2). Homopolymerization of 4FST under conditions identical to those in the copolymerization experiments yielded 76% of poly(4-fluorostyrene), P4FST (Table 1).

Table 1. Homo and copolymerization of 4-fluorostyrene (M1 ) with fluorine ring-substituted of 1,1-dicyanoethylenes, RC6 H3 CH C(CN)2 (M2 ) R P4FST 2,3-F,F 2,4-F,F 2,5-F,F 2,6-F,F 3-CF3 a

Yield a, wt%

N wt%

m2 in pol., mol%

Tg (◦ C)b

Mw, kD

76 53 59 69 51 62

7.51 7.22 7.64 8.30 8.01

40.02 38.14 40.87 45.29 48.88

104 130 156 118 122 116

19.60 16.60 8.00 13.62 12.31 13.58

Polymerization time was 48 h; Tg transition was observed by DSC.

b

Figure 1, represents the infrared spectrum of 2-(2,4difluorophenyl)-1,1-dicyanoethylene copolymer with 4FST. Vinylic band absorbance (C C) of TSE and 4FST at 1615 and 1618 cm−1, respectively, are absent, indicating that the copolymerization reaction has occurred. Characteristic band of this copolymer are 2939 cm−1 (aliphatic C-H stretch), 2233 cm−1 (C≡N stretch). Stretching bands at 1605, 1510, 1426 cm−1 corresponding to the benzene rings of both comonomers, as well as a doublet at 970, 835 cm−1 associated to C-H out of plane deformations. Similar observations can be made for the IR spectrum of all TSE copolymers. Figure 2 represents the 1H-NMR of 2-(4-trifluoromethylphenyl)-1,1-dicyanoethylene and 4FST copolymer. The broadening of the NMR signals in the spectra of the copolymer is apparently associated with Head-to-Tail (A) and Head-to-Head (B) structures, which formed through the attack of 4-fluorostyrene ended radical on both sides of TSE monomers (Fig. 3). The presence of both configurations Head-Tail and Head-Head structures were observed in the copolymers of styrene and 2-phenyl-1,1-dicyanoethene (5). The 1H-NMR spectra show a broad signal of TSE and 4FST aromatic protons at 6.0–8.0 ppm, which results from overlapping multiplets of four, spin system. The resonance at 4.0–3.25 ppm is assigned to the styrene backbone protons, methylene in structure (A) and methane in structures (B) which are in close proximity to cyano groups in TSE4FST diads or in 4FST centered TSE-4FST-TSE triads. The resonance in the range 2.5–3.3 ppm is assigned to the methine protons of fluorinated TSE. This assignment is based on the comparison with the methine proton absorption in Head to-Head and Head-to-Tail polystyrenes (5). The overlapping resonances in the 0.8–1.8 ppm range are attributed to the methine protons of 4FST-4FST dyads. The 13C-NMR spectrum of 2-(4-trifluoromethylphenyl)1,1-dicyanoethylene and 4FST (Fig. 4) also supports the suggested skeletal structure of the copolymers. By comparing the chemical shifts of 13C-NMR in P4FST homopolymer with those of 2-phenyl-1,1-dicyanoethylene and 4FST (31), the assignments of peaks are as follows: 160–165 ppm (phenyl carbons bonded to fluorine atoms of TSE and 4FST), 121–140 ppm (phenyl carbons), 110–120 ppm (CN) of TSE unit and 35–50 ppm (methine and methylene backbone carbons of TSE and 4FST). The

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Atlas et al. CN CN

CN

H2 C

H C

H C m

n

ABCN

CN

Toluene

R

R

F

F

R= 2,3-F,F; 2,4-F,F; 2,5-F,F; 2,6-F,F; 4-CF3

absorption at 58 ppm is assigned to the quaternary carbon of TSE (C(CN)2 ). In addition, we noted also the absence of the vinyl bond at 159 ppm ( CH) and 138 ppm ( C) associated to TSE monomer. All these 13C-NMR data showed that the radical copolymerization between TSE and 4FST occurred. According to nitrogen analysis, between 38 and 49 mol% of TSE monomer is present in the copolymers (Table 1). The copolymers prepared in the present work are all soluble in ethyl acetate, DMF, CHCl3 and insoluble in petroleum

ether, and heptane. The copolymerization of the fluorine ring-substituted TSE with 4FST results in formation of copolymers with weight- average molecular masses 8.0 to 17 kD. 3.4 Reactivity Ratios 3.4.1 Low Conversion The kinetics of radical copolymerization of 4FST (M1 ) with 2-(2,4-difluorophenyl)-1,1-dicyanoethylene (M2 ) was

95

60

1605. 78

55 50 45 40

734. 80 835. 40

65

970.41

70

1139.84 1089.54

75

1227.21 1161.02

80

1425.76

2939.11

85

1272.21

2233. 53

90

% Transmittance

35 30

1510.80

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Sch. 2. 4FST-TSE copolymer synthesis.

25 20 15 10 3500

3000

2500

2000

1500

1000

Wavenumbers (cm-1)

Fig. 1. IR spectrum of copolymer based on 2-(2,4-difluorophenyl)-1,1-dicyanoethylene and 4FST. (Color figure available online.)

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Novel Copolymers of 4-Fluorostyrene

Fig. 2. 1H-NMR spectrum of 2-(4-trifluoromethylphenyl)-1,1-dicyanoethylene and 4-fluorostyrene.

R CN H 2C

CH CN

CN H2 C

*

H C

C H

* CN

(1)

n

R

H-T structure (A)

F F R δ−

δ+

H2C

C H

CN

Ph *

δ+

δ−

HC

C

Ph

H2 C

H C

C H

*

(2)

n

CN

CN

CN F

H-H structure (B)

Fig. 3. Head-to-Tail (A) and Head-to-Head (B) structures of copolymers of TSE and 4FST TSE monomers in structures (A) and (B).

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Fig. 4. 13C-NMR of 2-(4-Trifluoromethylphenyl)-1,1-dicyanoethylene and 4-fluorostyrene copolymer.

investigated at initial [M1 ]0 /[M2 ]0 molar ratios ranging between 30/70 and 70/30 to achieve a conversion less than 20% (Table 2). The relative reactivity of (M1 ) and (M2 ) can be estimated by assuming applicability of the copolymer composition equation (Eq. 1) of the terminal copolymerization model (2). m1 /m2 = [M1 ](r1 [M1 ] + [M2 ])/[M2 ]([M1 ] + r2 [M2 ])

(1)

m1 and m2 are the mole fractions of 4FST, and TSE monomer units in the copolymer, respectively; [M1 ] and [M2 ] are the concentrations of 4FST and TSE in the monomer feed, respectively. Fineman and Ross rearranged Equation 1 to Equation 2 (2): G = r1 H − r2

(2)

where G = X(Y−1)/Y, H = X2/Y, X = [M1 ]/[M2 ], and Y = m1 /m2.

In the absence of the self-propagation of TSE monomer (k22 = 0, r2 = 0), the Equation 2 yields Equation 3. G = r1 H

(3)

Thus, the plot of G against F yields a straight line with slope r1 = k11 /k12 . Figure 5 shows that reactivity of 4FST radical toward TSE (r1 ) is around 0.6 according to the Equation (3). The experimental curve (i.e., the molar ratio of 4FST (M1 ) units in the copolymer F1 vs. the molar ratio of (M1 ) units in the feed f1 ) is shown in Figure 6. Because r1 2,5-F,F (0.22) > 2,6-F,F (0.10). More detailed information on the copolymer composition at different monomer feed ratios would be necessary for the application of copolymerization models that would allow prediction of copolymer composition. 3.5 Thermal Properties Two key thermal properties were studied, glass transition temperature, T g , and thermal degradation, T d , determinated by differential scanning calorimetry (DSC) and by, thermogravimetric analysis (TGA), respectively. All the copolymers show a sharp transition from the glassy domain to the viscoelactic one, as evidenced by the presence of only a neat T g . Although DSC was also realized on all samples from 25 to 180◦ C, the absence of any crystallization or melting temperature was noted. The T g indicates that the copolymers exhibited an amorphous behavior (Fig. 7). Higher Tg of the copolymers in comparison with that of P4FST homopolymer, Tg = 104◦ C indicate substantial decrease of chain mobility of the copolymer due to high dipolar character of the structural unit and also the fluorine position. Information on the degradation of the copolymers was obtained from thermogravimetric analysis in nitrogen. The decomposition products were not analyzed in this study, and the mechanism has yet to be investigated. Figure 8 shows for example the TGA curves

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Heat Flow

-0.1

-0.2

(a)

-0.3

(b)

Tg=122 Tg=104

-0.4 (c)

Tg=130

-0.6

-0.7 40

60

80

100

120

140

160

180

T(°C)

Fig. 7. DSC traces of: (a) of 2-(2,6-difluorophenyl)-1,1-dicyanoethylene and 4-fluorostyrene copolymer, (b) 4-fluorostyrene homopolymer and, (c) 2-(2,3-difluorophenyl)-1,1-dicyanoethylene and 4-fluorostyrene copolymer.

performed under nitrogen for the thermal degradation of the copolymers of 4-fluorostyrene with 2-(2,4-difluorophenyl)-1,1-dicyanoethylene and 2-(2,3-difluorophenyl)1,1-dicyanoethylene. Results of analyses are summarized in Table 4. We can see that the copolymers began to de-

100

(a) (b)

80

weight loss %

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-0.5

60

grade in the range 214–260◦ C (Td onset). The introduction of fluorine atoms in the ring of phenyl does not change thermal stability of these copolymers similarly to 2-phenyl-1,1-dicyanoethylene copolymer with 4FST which is stable until 300◦ C (31). Figure 8 shows that the copolymers decompose on two steps. First is fast, which the polymers lose about 90% of their weight and the second is much slower. For example, the 2-(2,4-difluorophenyl)1,1-dicyanoethylene copolymer decomposed with much smaller content loses weight on heating in two stages with rapid decomposition of 93% of the sample in the 275–390◦ C range followed by much slower second stage decomposition in the 480–650◦ C range. According to the% of residual copolymers (Table 4), the depolymerization reaction could be suggested as the mechanism of their thermal decompositions.

40

Table 4. TGA data for fluorine ring-substituted of 2-phenyl-1,1dicyanoethylene (TSE) copolymers with 4-fluorostyrene

20

TGA (◦ C) 0 100

200

300

400

500

600

700

800

T(°C)

Fig. 8. TGA Thermogram of (a): 2-(2,4-difluorophenyl)1,1-dicyanoethylene and (b): 2-(2,3-difluorophenyl)-1,1dicyanoethylene copolymers.

R (TSE) 2,3-F,F 2,4-F,F 2,5-F,F 2,6-F,F

Onset

10% wt loss

50% wt loss

Residue (%)

240 260 220 214

275 293 274 232

325 339 333 324

0.75 0.24 0.38 0.67

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Novel Copolymers of 4-Fluorostyrene 3.6 Dielectric Properties

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Broadband dielectric spectroscopy was performed to characterize molecular motions in P4FST and 4FST copolymer of 2-(2,4-difluorophenyl)-1.1-dicyanoethylene The goal of this study is to explore the incorporation of fluorinated TSE units in the dielectric properties of these copolymers and to establish the structure-properties relationships. 3.6.1 P4FST Figure 9 shows isochronal scans temperature at fixed frequencies 103 Hz, 1.09 kHz, 11.6 kHz and 123 kHz of the real permittivity ε (Fig. 9a) and the dissipation factor tan δ (Fig. 9b), respectively, for P4FST. Two successive parts can be pointed out from the analysis of ε and tan δ according to the temperature zone: the first one from 0 to 95◦ C and the second one from 95 to 160◦ C. In the glassy state of P4FST in the region between 0 to 95◦ C (below T g = 104◦ C), the ε and tan δ had low dependence on frequency, no dielectric relaxation was observed in tanδ curves (Fig. 9b), the dipolar orientation is mainly blocked (20). As a consequence, the real part of permittivity is almost constant (ε = 2.1) corresponding to typical value for the atomic and electronic polarization (33). This value is similar to the insulating commercial polystyrene (2.5