Synthesis of polystyrene modified with fluorine atoms: Monomer reactivity ratios and thermal behavior

Abstract

Homo‐ and copolymers of 4‐fluorostyrene (FSt) and styrene (St) were synthesized with different feed ratios using free radical bulk polymerization with azobisisobutyronitrile (AIBN) as initiator. It yielded series of (co)polymers with various amounts of included FSt, P(St‐co‐FSt) (5–50 mol%) and PFSt. The effect of the initiator concentration on the molecular weights of the homopolymers, that is, PSt and PFSt was investigated. Copolymer compositions were determined by nuclear magnetic resonance spectroscopy. The relative reactivity ratios of both comonomers were determined by applying the conventional linearization methods of Jaacks (J), Finemann–Ross (F–R), inverted Finemann–Ross (IF–R), and Kelen‐Tüdos (K–T). The reactivity ratios values of St and FSt obtained from J plot are 1.06 and 0.84, F–R plot are 1.18 and 1.06, IF–R 1.01 and 0.86, and K–T plot 1.04 and 0.88, respectively. Thermal properties of prepared (co)polymers, that is, glass transition temperature (Tg) and thermal stability, were determined from differential scanning calorimetry and thermogravimetrical measurements. The lack of significant influence of FSt comonomer content on Tg of (co)polymers was observed. Additionally, the thermal degradation kinetics of obtained PSt and PFSt was studied by thermogravimetric analysis. Kinetic parameters such as the thermal decomposition activation energy (E) and frequency factor (A) were estimated by Ozawa model [E(O) and A(O), respectively] and Kissinger model [E(K) and A(K), respectively]. The activation energy and the frequency factor of PFSt (253 kJ/mol) were higher than PSt (236 kJ/mol). The resulting activation energies estimated using the two methods were quite close. POLYM. ENG. SCI., 54:1170–1181, 2014. © 2013 Society of Plastics Engineers

Halogeno‐modified polystyrene: monomer reactivity ratios, thermal behaviour and flammability

“…As evident from the table, a lack of influence of the presence of F atoms in polymers on T g is detected, contrary to that of Br and Cl atoms. A similar result was obtained in the case of copolymers of 4‐fluorostyrene and St, reported in our previous work . Introduction of Br and Cl atoms into polymers results in an increase of the T g values of the homopolymers (PBrSt and PClSt), and an increase of comonomer (ClSt and BrSt) content in the copolymers causes an increase of T g of the (co)polymers.…”

“…The higher temperatures ( T 5% , T 10% , T max ) are achieved for P5FSt, and, as expected, the larger the 5FSt loading in the copolymers, the higher the thermal stability observed. This is in contrast to copolymers of 4‐fluorostyrene and St in which a negligible impact of 4‐fluorostyrene on thermal properties was detected . Considering samples with various concentrations of ClSt and BrSt, only a very slight improvement in thermal stability of PSt is observed.…”

“…Value of E is higher about 100 kJ mol −1 than for pure PSt, and value of A increases from 10 14 to 10 21 s −1 . Poly(4‐fluorostyrene) reported in previous work exhibited a thermal decomposition activation energy about 17 kJ mol −1 higher than PSt …”

Polystyrene with trifluoromethyl units: Monomer reactivity ratios, thermal behavior, flammability, and thermal degradation kinetics

“…An example is a pair of St with 4‐fluorostyrene (FSt) ( r St = 0.96, r FSt = 0.85) and St with 2,3,4,5,6‐pentafluorostyrene (5FSt) ( r St = 0.44 and r 5FSt = 0.42) . These values were confirmed and reported in our previous works . As can be seen, the values of relative reactive ratios of fluorinated comonomers decrease for monomers covalently bonded with fluorine atoms with an increasing fluorine atoms into macromolecule ( r FSt = 0.85 > r StCF3 = 0.54 > r 5FSt = 0.42 > r St(CF3)2 = 0.13).…”

Coordination‐Insertion Copolymerization of Norbornene and p‐Substituted Styrenes Using Anilinonaphthoquinone‐Ligated Nickel Complexes

“…Copolymerization with functionalized monomer is preferable to post‐functionalization because functional groups can be installed with exact compositions by a simple process. Ring‐substituted S derivatives provide wide application, in which the substituents can be varied from electron‐withdrawing to electron‐donating groups 20–22…”