Structure and properties of blends of poly(ethylene-co-vinyl alcohol) with poly(styrene-co-maleic anhydride)

Blends of polystyrene (PS) and polyurethane (PU) elastomer were obtained by melt mixing, using poly(styrene-co-maleic anhydride) (SMA) containing 7 wt % of maleic anhydride groups as a reactive compatibilizer. Polyurethanes containing polyester flexible segments, PU-es, and polyether flexible segments, PU-et, were used. These polyurethanes were crosslinked with dicumyl peroxide or sulfur to improve their mechanical properties. The anhydride groups of SMA can react with the PU groups and form an in situ graft copolymer at the interface of the blends during their preparation. The rheological behavior was accompanied by torque versus time curves and an increase in the torque during the melt mixing was observed for all the reactive blends, indicating the occurrence of a reaction. Solubility tests, gel permeation chromatography, and scanning electronic microscopy confirmed the formation of a graft copolymer generated in situ during the melt blending. These results also indicate that this graft copolymer contains COC bond between SMA and PU chains.

Section: Resultssupporting

confidence: 63%

In situ compatibilization of polystyrene and polyurethane blends by using poly(styrene‐co‐maleic anhydride) as reactive compatibilizer

Cassu

Felisberti

2001

“…Reactive groups can be either part of the main backbone macromolecular chain, or side chain groups. Copolymers are the most used compatibilizers, while SMA can be used for the reactive compatibilization of PS with other polymers 30–33. The dynamic mechanical properties and the morphology of similar blends are particularly interesting 34…”

Section: Resultsmentioning

confidence: 99%

Blends of polymers with similar glass transition temperatures: A DMTA and DSC study

Bikiaris

Prinos

Botev

et al. 2004

Self Cite

ABSTRACT:The miscibility of different polymer blends was studied with dynamic mechanical thermal analysis (DMTA) in conjunction with differential scanning calorimetry (DSC). The blends were prepared by melt mixing polymers having similar glass transitions such as polyglutarimide (PGI), styrene-co-maleic anhydride random copolymers (SMA), and polystyrene (PS). In PGI/SMA blends, there is only one glass transition detected with DMTA. In the case of PGI/SMA14 blends, the single glass transition temperature is due to their full miscibility. However, PGI/SMA8 blends are immiscible throughout the whole composition range as was verified by optical observation (opaque appearance), DSC, and scanning electron microscopy. The observation of only one glass transition by DMTA was attributed to weak interactions that take place between the two polymers, leading to partial mutual solubility and bringing the slightly different T g temperatures of the pure polymers even closer. In SMA8/SMA14 blends, there are two glass transitions detected with DSC as well as with DMTA, indicating that the two copolymers are immiscible. However, in all compositions, shifts of the glass transitions were observed with DMTA, which is evidence of partial miscibility. The observation of immiscibility was easiest in PS/SMA blends by both techniques, because of the bigger difference in glass transition temperatures of the initial polymers.

“…The addition of SMA into blends of amorphous polyamide (a‐PA) and the styrene–acrylonitrile copolymer (SAN) leads to the enhancement of interfacial adhesion and the tensile properties were improved until 10 wt % of SMA content 6. SMA has also been used in blends containing poly(ethylene‐ co‐ vinyl alcohol) (EVAL) prepared by melt mixing 7…”

Section: Introductionmentioning

confidence: 99%

Polystyrene and polyether polyurethane elastomer blends compatibilized by SMA: Morphology and mechanical properties

Cassu

Felisberti

2001

Blends of polystyrene (PS) and the polyether polyurethane elastomer (PUet) were prepared by melt mixing using poly(styrene-co-maleic anhydride) (SMA) containing 7 wt % of maleic anhydride as a compatibilizer. The polyurethane in the blends was crosslinked using dicumyl peroxide or sulfur. The content of maleic anhydride was varied in the blends through the addition of different SMA amounts. The morphology of the blends was analyzed by SEM and a drastic reduction of both the domain size and its distribution was observed with increase of the anhydride content in the blends. The morphology of the PU-et blends also showed dependence on the crosslinker agent used for the elastomer, and larger domains were obtained for the elastomer phase crosslinked with dicumyl peroxide. The mechanical properties of the blends were evaluated by flexural and impact strength tests. The blend containing 0.5 wt % of maleic anhydride and 20 wt % of PU-et crosslinked with sulfur showed the highest strength impact, which was three times superior to the PS strength impact, and the blends containing 20 wt % of PU-et crosslinked with dicumyl peroxide showed the highest deflection at break independent of the anhydride content.