G. Bogdanić

Miscibility in blends of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) with homopolymers of halogen-substituted styrene derivatives

Abstract Miscibility and phase behaviour in blends of poly(p-fluorostyrene) (PpFSt), poly(o-fluorostyrene) (PoFSt), poly(p-chlorostyrene) (PpClSt), poly(o-chlorostyrene) (PoClSt), poly(p-bromostyrene) (PpBrSt) and poly(o-bromostyrene) (PoBrSt) with partially sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) copolymers [i.e. systems of the type ( A ) n 1 ( C 1− y D y ) n 2 have been studied by d.s.c. as a function of temperature and degree of sulfonylation. For all the para-substituted styrene polymers/SPPO blends studied, limited miscibility regimes are found. A miscibility regime is also found for PoFSt/SPPO blends. However, PoClSt and PoBrSt are not miscible with any SPPO. Using the mean-field approach, we have calculated all the pertinent segmental interaction parameters for these blends. In several systems, certain blends have been found to exhibit lower critical solution temperature behaviour.

Miscibility and phase behaviour in poly(2,6-dimethyl-1,4-phenylene oxide) and poly(fluorostyrene-co-bromostyrene) blends

Abstract Copolymers of ortho(para) fluorostyrene and ortho(para) bromostyrene with a range of copolymer compositions were prepared by free radical polymerization in toluene solution using azobis(isobutyronitrile). The miscibility and phase behaviour of these copolymers in blends with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) have been studied by differential scanning calorimetry. Of the four possible copolymer systems, miscibility was observed only for PPO/poly( o -fluorostyrene-co- p -bromostyrene) blends in which the copolymer contains between 11 and 73 mol% p -bromostyrene. High temperature phase separation in the miscible blends is a function of copolymer composition and of the thermal history. The results can be explained on the basis of the mean field theory of phase behaviour for homopolymer-copolymer systems.

Miscibility in blends of phenylsulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) and poly(p-fluorostyrene-co-o-fluorostyrene)

Abstract Miscibility and phase separation in blends of random copolymers of p -fluorostyrene and o -fluorostyrene [P( p FSt- co - o FSt)] with phenylsulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) copolymers in which the degree of sulfonylation ranges from 4 to 92 mol% have been studied by differential scanning calorimetry (d.s.c.) at temperatures up to 320°C. It was found that miscibility depends on isomeric composition, the degree of sulfonylation, and temperature. Certain blends exhibit lower critical solution temperature ( LCST ) behaviour.

Miscibility behaviour of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) copolymers in the blends with poly(styrene-co-maleic anhydride) and with poly(α-methylstyrene-co-maleic anhydride)

SummaryThe miscibility behaviour of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) of the different degree of sulfonylation blended with poly(styrene-co-maleic anhydride) or poly(α-methylstyrene-co-maleic anhydride) was studied. The critical degree of sulfonylation for phase separation in these blends was found to be 55 mole % and 66 mole %, respectively. The miscibility behaviour was analyzed on the basis of the mean field treatment and studied by DSC.

Structural Differences Between Copolymers of Acryl‐ and Methacryl‐dicyclohexylurea with Ethylene Glycol Dimethacrylate and their Thermal Degradation Products

The present paper describes structural characteristics of crosslinked copolymers of acryl‐dicyclohexylurea (A‐DCU) and methacryl‐dicyclohexylurea (MA‐DCU) with ethylene glycole dimethacrylate (EDMA). Both copolymers decompose when heated at temperatures between 180–250°C under the separation cyclohexylisocyanate (C6H11NCO) yielding nanoporous copolymers of poly(A‐CHA‐co‐EDMA) and poly(MA‐CHA‐co‐EDMA). The comparison was also made between structural characteristics of crosslinked nanoporous copolymers of poly(A‐CHA‐co‐EDMA) and poly(MA‐CHA‐co‐EDMA) and nonporous crosslinked model compounds poly(A‐CHA‐co‐EDMA) and poly(MA‐CHA‐co‐EDMA).

POLYMERIZATION OF N(p-PHENOXY-PHENYL)ACRYLAMIDE AND COPOLYMERS WITH STYRENE

Copolymerization of N(p-phenoxy-phenyl)acrylamide (PhOPhAA) with styrene (St) in butanone at 70°C under different monomer-to-monomer ratios in the feed using AIBN as free-radical initiator is described. The total monomer concentration was 1 mol L−1. The copolymer composition was evaluated by the nitrogen content in copolymers. The reactivity ratios determined by the Kelen-Tüdös method indicates the random arrangement of monomers in the copolymer chain with an azeotropic point at the equimolar ratio of comonomers. Mean sequence length distribution in copolymers was estimated from r1 (PhOPhAA) = 0.53 and r2 (St) = 0.48. Activation energy determined by the Arrhenius method is 118 kJ mol−1. Copolymers are thermally stable up to a temperature of 400°C under TGA conditions. Tgs and higher transition temperatures increase by increasing the content of PhOPhAA in copolymers. The same was also found for molecular weights of copolymers.

Phase behaviour in blends of poly[styrene-co- ortho(para)-bromostyrene] and phenylsulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) copolymers

Abstract Random copolymers of styrene with ortho- or para-bromostyrene differ substantially in their blend behaviour with partly sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO). Copolymers of styrene with ortho-bromostyrene exhibit a very narrow window of miscibility in comparison with styrene-para-bromostyrene copolymer blends with SPPOs. The experimental results can be accounted for on the basis of individual segmental interaction parameters by applying mean-field theory.

FREE-RADICAL-INITIATED COPOLYMERIZATION OF 2-CHLOROSTYRENE, 4-CHLOROSTYRENE, AND 2,6-DICHLOROSTYRENE WITH MALEIC ANHYDRIDE

The title copolymers have been prepared by the free-radical-initiated copolymerization of 2-chlorostyrene (2-ClSt), 4-chlorostyrene (4-ClSt) and 2,6-dichlorostyrene (2,6-DClSt) with maleic anhydride (MAn) in toluene at 65°C. Copolymers of chlorinated styrenes with MAn prepared under different monomer-to-monomer ratios in the feed have alternating composition. In all cases, the mixture of comonomers forms charge-transfer complex monomers (CTC). The initial rate of copolymerization increases with the increase of electron donors in the comonomer feed, and the highest rates were at the equimolar ratios of comonomers in the feed. The thermal stability of the polymers was measured by thermogravimetric analysis in nitrogen. Homopolymers decompose by a one-step mechanism, while copolymers are more thermostable and decompose by a two-step mechanism. Glass transition temperatures (Tgs) of homopolymers are lower than Tgs of copolymers. The number and weight average molecular weights of chlorinated copolymers are higher than those of the corresponding homopolymers.

Free‐Radical Initiated Polymerization of N‐methacryl‐N,N′‐diisopropylurea with Styrene

Free‐radical initiated copolymerization of N‐methacryl‐N,N′‐diisopropylurea (MA‐DiPrU) with styrene (St) was performed to low conversion by using dibenzoyl peroxide (Bz2O2) in butanone at 70°C. The copolymer composition was calculated on the basis of nitrogen content in copolymers. The reactivity ratios determined by the Kelen‐Tüdös method are: r1(MA‐DiPrU)=0.39 and r2(St)=1.03. In all cases, regardless of the monomer‐to‐monomer ratios in the feed, an excess of St was present in copolymers. Copolymers decompose under TGA conditions in nitrogen by a two‐step mechanism. In the first step between 180°C and 250°C, isopropylisocyanate (iPrNCO) separates by degradation of diisopropylurea in the side chain. The thermally stable residue represents the copolymer of methacryl‐isopropylamide (MA‐iPrU) with St, which decomposes by a one‐step mechanism between 280°C and 450°C.