Alejandra Opazo

Blends of poly(2-hydroxyethyl methacrylate)/ (styrene-co-dialkyl itaconates) and poly(N-vinyl-2-pyrrolidone)/(styrene-co-dialkyl itaconates)

SummaryBlends containing poly(N-vinyl-2-pyrrolidone) (PVP) and poly(hydroxyethyl methacrylate) (PHEMA) with (styrene-co-dimethyl itaconate) (Sty-co-DMI) and (styrene-co-diethylitaconate) (Sty-co-DEI) copolymers of three different compositions were studied. One Tg value over the whole range of compositions is observed for the majority of the blends, what is indicative of compatibility. The Gordon-Taylor kGT and the Couchman kC parameters were determined for all the blends in order to compare the strength of the interactions. The effect of the side chain structure of the copolymer on the miscibility of these blends is analyzed.

Blends of poly(vinylpyrrolidone)/poly(monoitaconates). I : Interpolymer complex formation

Abstract Blends containing poly(vinylpyrrolidone) (PVP) of three different molecular weights and poly(monoitaconates) (PMI) with different side chain structures were prepared. Polymer blends of various compositions were analyzed by Differential Scanning Calorimetry (D.S.C.). The calorimetric study was performed on films prepared from methanol and dimethylformamide (DMF). One Tg value is observed for the majority of the samples over a wide range of composition, but in all cases a minimum in the Tg-composition diagram is observed which is attributed to an interpolymer complex formation. The analysis of these systems in solution by using turbidimetry and viscometry techniques for PMMI/PVP confirms the results obtained in the solid state.

Solution properties of poly(di-1'-methylalkyl itaconates)

Abstract Di-1′-methylalkyl itaconates and the corresponding poly(di-1′-methylalkyl itaconates) (PD1′Al) containing 2-propyl (PDiPI), 2-butyl (PDiBI), 1′-methylbutyl (PDiAI), 1′-methylpentyl (PDiHI) and 1′-methyiheptyl (PDiOI) groups as side chains were synthesized and characterized. The polymers were fractionated by fractional precipitation. The fractions were characterized by viscometry in THF and acetone, and by light scattering and size exclusion chromatography in THF. The K a and a parameters of the Kuhn—Mark—Houwink—Sakurada equations were determined in THF and acetone. The stiffness of the polymer chain was estimated through the rigidity indices, a, and the characteristic ratio, C α , using the conformational parameter K Θ obtained from the Stockmayer—Fixman plots. The effect of the side-chain structure on the stiffness, conformational behaviour and glass transition temperatures, T g , of these polymers is discussed and the results compared with those corresponding to other related polymer analogues.

Miscibility of poly(2,6-dimethyl-1,4-phenylene oxide)/poly(vinyl pyrrolidone) blends

The miscibility of blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and poly(vinylpyrrolidone) (PVP) was studied by differential scanning calorimetry (DSC) through the analysis of the glass transition temperature Tg. The dependence of Tg with the annealing temperature was determined for PPO and PVP samples of different molecular weights. The phase diagrams for blends containing three different PVP samples were established. Blends of PPO and PVP were found to be miscible for composition lower than 30% and higher than 65% of PVP. A inmiscibility window between 30 and 65% of PVP is also described.

Copolymers of maleic anhydride with monooctyl itaconate. Synthesis, characterization and viscometric behaviour

Abstract Maleic anhydride-monooctyl itaconate copolymer was synthesized by radical polymerization. The viscometric behaviour was studied in dilute solution. The copolymer was fractioned and characterized by size exclusion chromatography membrane osmometry and viscometry. The classical viscometric relationships were established in several solvents. The conformational and thermodynamic parameters Kθ and B were evaluated from viscosity data in good solvents using the Stockmayer Fixman, Berry and Kamide-Moore extrapolations. The rigidity parameters σ and C∞ show flexibility of the polymer chain, due to the incorporation of the maleic anhydride units when the copolymer is compared with the corresponding homopolymer poly(mono-n-octyl itaconate).

Thermal stability of poly(mono-n-alkylitaconates) and mono-n-alkylitaconate-co-vinylpyrrolidone copolymers I

Poly(monoitaconates) containing octyl, decyl and dodecyl groups and random monoalkylitaconate-co-vinylpyrrolidone copolymers were studied by thermogravimetric analysis. Copolymers of mono-n-octylitaconate (MOI), mono-n-decylitaconate (MDI), and mono-n-dodecylitaconate (MDoI), respectively, with N-vinyl-2-pyrrolidone (VP) of different compositions were studied by dynamic thermogravimetric analysis. The thermal stability of the copolymers depends on the structure of the monoitaconate comonomer and on the composition of the copolymer The kinetic analysis of the degradation data shows that the thermal decomposition of these copolymers can be described by several kinetic orders depending on the copolymer and on the composition. The relative thermal stability of the copolymers increases as the VP content increases and as the length of the side chain of the itaconate increases, following the same trend as the flexibility of the copolymers in solution.ZusammenfassungPoly(monoitaconate), die Octyl-, Decyl- und Dodecylgruppen enthalten, sowie statistische Monoalkyl-itaconate-co-vinylpyrrolidon Copolymere und Copolymere des N-vinyl-2-pyrrolidons mit Mono-n-octylitaconaten (MOI), Mono-n-decylitaconaten (MDI) und Mono-n-dodecylitaconaten (MDoI) verschiedener Zusammensetzungen wurden durch dynamische TG Analyse untersucht.Die thermische Beständigkeit der Copolymere hängt von der Struktur der Monoitaconatecomonomere und von der Zusammensetzung der Copolymere ab. Die kinetische Auswertung der TG-Kurven ermöglicht eine Beschreibung der thermischen Zersetzung der Copolymere nach verschiedenen kinetischen Ordnungen, je nach Copolymerart und Zusammensetzung. Die Copolymere sind thermisch stabiler, wenn die VP-Gehalt bzw. die Seitenkettenlänge, zunimmt. Dieses Verhalten zeigt im Grunde genommen die gleiche Tendenz, wie die Beweglichkeit dieser Copolymere in Lösung.

Maleic acid-alt-styrene copolymer as compatibilizer for poly(ethylene oxide)-poly(styrene) blends

Maleic acid-alt-styrene (MAaS) copolymer with number-average molecular weight [Mbar] n = 2500 was used as a compatibilizer in blends of poly(ethylene oxide) (PEO) and poly(styrene) (PS). PEO with weight-average molecular weight [Mbar] w = 105 (PEO100) and two PS samples with [Mbar] w = 9 × 104 and 4 × 105, respectively (PS90 and PS400, respectively) were used. A depression of the melting temperature T m of PEO in blends containing MAaS relative to pure PEO and PEO/PS blends was observed. The melting enthalpy ΔH m for the PEO/PS blends containing MAaS was lower than those of pure PEO and PEO/PS blends without compatibilizer. The crystallization kinetics of PEO and the blends were studied by differential scanning calorimetry (DSC) at different crystallization temperatures T c. Flory-Huggins interaction parameters χ12 for the blends were estimated. Their values are in good agreement with those obtained for similar systems and suggest that the free energy of mixing ΔG mix should be negative. Polarized optical microscopy shows differences in the macroscopic homogeneity of the blends containing compatibilizer that could be attributed to a compatibilization process.

THERMAL STUDIES OF POLY(ESTERS) CONTAINING SILICON OR GERMANIUM

Las propiedades termicas de poli(esteres) conteniendo silicio o germanio en la cadena principal y derivados de los difenoles bis(4-hidroxifenil)-difenilsilano o bis(4-hidroxifenil)-difenilgermano y los cloruros de los acidos isoftalico y tereftalico fueron estudiadas mediante calorimetria diferencial de barrido y termogravimetria dinamica. Los poli(esters) derivados del acido tereftalico mostraron mayores valores de Tg y estabilidad termica que aquellos derivados del acido isoftalico. Los poli(esteres) conteniendo Ge mostraron mayores valores de Tg pero menores valores de temperatura de descomposicion termica que sus analogos conteniendo Si

Conformational transition in (maleic anhydride mono-n-octyl itaconate) copolymer

SummaryThe dependence of intrinsic viscosity [η] on temperature for fractions of poly(maleic anhydride-co-mono-n-octylitaconate) [p(MA-co-MOI)] was studied. A discontinuity in [η] as function of temperature similar to that of poly(mono-n-octylitaconate) (PMOI) is found which has been attributed to a conformational transition of the polymer chain. This conformational transition can be removed by the addition of poly(dimethylsiloxane) (PDMS). The effect is interpreted in terms of interpolymer complexation.

Thermal Stability of Aromatic Poly(monoitaconates)

Abstract Thermogravimetric analysis of poly(mono-benzyl itaconate), (PMBzI) poly(mono-ethylphenyl itaconate) (PMEPI) and poly(mono-n-propyl itaconate) (PMPPI), were performed by dynamic thermogravimetry. The thermal stability of these polymers depends on the side chain structure. The kinetic analysis of the degradation data shows that the thermal decomposition of these polymers follows a 0.5 kinetic order in all the cases.