Acrylonitrile Content In SAN Research Articles

Study of compatibility, morphology structure and mechanical properties of CPVC/ABS blends

AbstractCompatibility, morphology structure, and mechanical properties of CPVC/ABS (Chlorinated polyvinyl chloride/acrylonitrile‐butadiene‐styrene) blends were studied. The core‐shell ratios of ABS were set at 40/60 and 70/30. The interface interactions between ABS and CPVC were changed by modifying the acrylonitrile (AN) content of the shell. The compatibility of CPVC with the shell of ABS was studied by the blends of CPVC/SAN with different AN content in SAN. Dynamic mechanical analysis results of CPVC/SAN were in accordance with the morphological properties of CPVC/ABS. The mechanical properties of CPVC/ABS blends in which the polybutadiene content was set to 15 wt % were studied. Results showed, with the change of AN content, the impact strength followed different way for CPVC/ABS blends with different core‐shell ratios of ABS because of the influence of the compatibility. When the core‐shell ratio was 40/60, the CPVC/ABS blends were much ductile in more widely AN range than the blends, whereas the core‐shell ratio of ABS was 70/30. The differences also showed in the SEM micrographs by the investigation of toughening mechanism. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Viscoelastic properties of blends of poly(methyl methacrylate) and poly(styrene-co-acrylonitrile) having various acrylonitrile contents

Dynamic viscoelastic properties of blends of poly(methyl methacrylate) (PMMA) and poly(styrene-co-acrylonitrile) (SAN) with various AN contents were measured to evaluate the influence of SAN composition, consequently χ parameter, upon the melt rheology. PMMA/SAN blends were miscible and exhibited a terminal flow region characterized by Newtonian flow, when the acrylonitrile (AN) content of SAN ranges from 10 to 27 wt %. Whereas, PMMA/SAN blends were immiscible and exhibited a long time relaxation, when the AN content in SAN is less than several wt % or greater than 30 wt %. Correspondingly, melt rheology of the blends was characterized by the plots of storage modulus G′ against loss modulus G″. Log G′ versus log G″ plots exhibited a straight line of slope 2 for the miscible blends, but did not show a straight line for the immiscible blends because of their long time relaxation mechanism. The plateau modulus, determined as the storage modulus G′ in the plateau zone at the frequency where tan δ is at maximum, varied linearly with the AN content of SAN irrespective of blend miscibility. This result indicates that the additivity rule holds well for the entanglement molecular weights in miscible PMMA/SAN blends. However, the entanglement molecular weights in immiscible blends should have “apparent” values, because the above method to determine the plateau modulus is not applicable for the immiscible blends. Effect of χ parameter on the plateau modulus of the miscible blends could not be found. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Study of Adhesion and Fracture of Polymer Laminates by Imaging of Interfaces

AbstractThe adhesion and fracture of styrene‐acrylonitrile random copolymer and poly(methyl methacrylate) (PMMA/SAN) laminates were studied. They showed a drastic transition from brittle to ductile on varying the acrylonitrile (AN) content in SAN, with changes in the fracture mode from interfacial failure to cohesive fracture. Energy‐filtering transmission electron microscopy (EFTEM) and scanning electron microscopy (SEM) with an in‐lens detector system were employed to study the interface and adhesion of the laminates. The effect of the AN content in SAN on the PMMA/SAN interfacial structures could be revealed by imaging of the interfaces using elemental mapping and electron energy loss spectroscopy (EELS). The in‐lens detector system in the SEM enabled the differentiation of thin interfaces with poor adhesion strength, yielding smooth and flat fracture surfaces, where numerous nanosized fibrils were formed normal to the surfaces.magnified image

Window of Acrylonitrile Content for Miscibility in Blends Comprising Poly(styrene-co-acrylonitrile)s and Poly(benzyl methacrylate)

For the first time, miscibility between poly(styrene-co-acrylonitrile) (SAN) and poly(benzyl methacrylate) (PBzMA) was proved. The miscibility window was found in SAN/PBzMA as the copolymer structure was varied systematically by altering weight percent of the acrylonitrile (AN) unit in the SAN copolymers. The lower bound of AN content in SAN for miscibility of SAN/PBzMA blend is 3.5 wt %, and the upper bound is 24.4 wt % AN in the copolymer. The trend of Tg broadening and LCST (cloud point) behavior for the SAN/PBzMA blends in that these phase-related quantities were all affected by AN content in SAN copolymers. Within the window, the copolymer/polymer mixtures formed a true miscible blend system. The effect of SAN structure (by controlling AN weight percent) on the window miscibility of SAN/PBzMA blends is interpreted and discussed in detail.

Morphology and physical properties of SAN/NBR blends: The effect of AN content and melt viscosity of SAN

To study the effect of dispersed poly(butadiene-co-acrylonitrile) (NBR) rubber size on the physical properties of poly(styrene-co-acrylonitrile) (SAN)/NBR blends, SANs with various melt viscosities and acrylonitrile (AN) contents were examined. The dispersed size of NBR, whose AN content is 30 wt %, was reduced as the melt viscosity of the SAN matrix was increased or as the AN content of the SAN matrix was reduced in the range of 19–32 wt %. As the melt viscosity of the SAN matrix was increased, the damping peak of the NBR phase moved to a higher temperature, and as the AN content of SAN was reduced, the damping peak of the SAN phase moved to a lower temperature. Higher values of impact strength and elongation at break and reduced yield behavior at a low shear rate were observed at a finer dispersion of NBR. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 935–941, 1999

Studies on miscibility in polycarbonate/poly(styrene-co-acrylonitrile) blends by ellipsometry

The interfacial thickness between immiscible polymers, bisphenol A polycarbonate (PC) and styrene–acrylonitrile random copolymers (SAN), was measured by ellipsometry as a function of temperature and acrylonitrile content in SAN, in order to study the miscibility between PC and SAN. Both the temperature and copolymer composition (AN content) dependence of the interfacial thickness in the equilibrium state indicated a maximum. Using the values of the interfacial thickness, it is possible to calculate the polymer–polymer interaction parameter χAB between PC and SAN. The χAB exhibited the lowest positive value at about 200°C for each copolymer composition due to the maximum of the interfacial thickness, i.e. at low temperature range, χAB decreased with increasing temperature, then χAB increased at high temperature range. This behaviour implies the possibility of the coexistent behaviour of upper and lower critical solution temperature (UCST and LCST) in the phase diagram of the mixture consisting of polymers with suitable molecular weight. This coexistent behaviour of UCST and LCST was confirmed by measuring cloud point curves of the mixtures having lower molecular weight PC. On the other hand, the copolymer composition dependence of χAB also has a minimum in a certain copolymer composition, which leads to the miscibility window behaviour. From these results, it was shown that there appeared to be a loop-type miscibility window (`miscibility egg') in the miscibility diagram of copolymer composition versus temperature of PC/SAN. From the calculation based on these results, it has also been shown that all three segmental interaction parameters χi/j of PC/SAN, i.e. χS/C, χAN/C and χS/AN, decreased with increasing temperature monotonically. It was predicted that the LCST behaviour in PC/SAN mixtures could occur due to the remarkable decrease of interaction χS/AN between comonomers in SAN at high temperature, without the free volume contribution.

Structure development in the phenolic resin-poly(styrene-ran-acrylonitrile) copolymer blends

Single-phase mixtures of phenolic derivatives with poly(styrene-ran-acrylonitrile) copolymers (SAN) were cured in the presence of hexamethylenetetramine, and the effect of the acrylonitrile (AN) content in SAN on the phase separation and reaction kinetics during curing were investigated by light scattering, differential scanning calorimetry (DSC), and optical microscopy (OM). DSC measurements revealed that the reaction rate does not have a significant effect on the AN content in SAN but depended on the fraction of multifunctional phenols in total phenols. The time variation of the light scattering profile during cure demonstrated the characteristic feature for spinodal decomposition. OM observation revealed that a co-continuous two-phase structure appeared after a certain time lag and coarsened to a spherical domain structure consisting of phenolic-rich particles dispersed in the SAN-rich matrix. The periodic distance, Λm in the phase-separated structure changed with curing time, as follows. The higher the miscibility between phenolic resin and SAN, the higher the fraction of multifunctional phenols in total phenols, the higher the SAN composition, and the lower the cure temperature, the shorter the Λm was. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 757–764, 1998

Effects of mixing ratio and monomer composition on morphology and mechanical properties of SMI/SAN blends

This article was concerned with the morphology and mechanical properties of blends of poly(styrene-co-N-phenylmaleimide) (SMI) and poly(styrene-co-acrylonitrile) (SAN) as functions of the mixing ratio of the blends and the acrylonitrile content in SAN. Differential scanning calorimetry (DSC) and field-emission scanning trans-mission electron microscopy (FE-STEM) were used for the morphology characterization, and tensile strength and KI (stress intensity factor in mode I), for the mechanical property comparison. The miscibility of the polymers was clearly distinguished using the number of glass transitions shown in the DSC thermograms. FE-STEM supports the DSC results, assisting in understanding the blend morphology for the immiscible blends in terms of the shape and size of the dispersed phase. The mechanical properties suggest that the miscible blends are superior to the immiscible counterparts and illustrate how the acrylonitrile content in SAN and the molecular weights of SMI and SAN affect the toughness of the miscible blends. We conclude from the study that the miscibility between SMI and SAN is an important factor for toughness enhancement of the blends. As a miscible blend, the mechanical properties improve with increase of the acrylonitrile content in SAN and the molecular weight of SMI and SAN. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 513–523, 1998

Effect of the type of SAN in SAN/CPE blend: Morphology, mechanical, and rheological properties

The effect of the molecular weight and acrylonitrile (AN) content of the styrene-acylonitrile copolymer (SAN) on the morphology, mechanical, and rheological properties of SAN/chlorinated polyethylene (CPE) blends was studied. The interaction between dispersed particle and matrix is expected to be optimal at the 25% AN content of SAN. Phase inversion from a dispersion to a continuous phase appears to occur above 50 wt % CPE. Mechanical properties increased with molecular weight at a constant AN content of SAN. Morphological, mechanical, and rheological properties were more sensitive to the AN content, rather than the molecular weight of SAN. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 27–36, 1998

Compatibilizing effect of poly(methyl methacrylate) in polycarbonate/poly(acrylonitrile-co-butadiene-co-styrene) blend

It is shown that PMMA can compatibilize the polycarbonate blend with ABS whose acrylonitrile content in SAN is 34-35 wt%

Rheological properties of poly(?-caprolactone) and poly(styrene-co-acrylonitrile) blends

Rheological properties of poly(e-caprolactone) (PCL) and Poly (styrene-co-acrylonitrile) (SAN) blends were examined as a function of the acrylonitrile (AN) content in SAN, to systematically understand the correlation between the interaction parameter and the theological properties of miscible polymer blends. When the plateau modulus (GN0) and zero shear viscosity (η0) of the PCL/SAN blends are plotted against the AN content in SAN, a minimum is observed. Qualitatively, the results obtained parallel the variation of the interchain interaction with the AN content. The negative deviation ofGN0 andη0 from linearity seems to be attributed to the increase in the entanglement molecular weight between dissimilar chains which results from the chain extension caused by interchain interaction.

Melting point depression in poly(?-caprolactone) / poly(styrene-co-acrylonitrile) blends

The melting point depression of poly(ɛ-caprolactone)/poly(styrene-co-acrylonitrile) (PCL/SAN) blends with changes in acrylonitrile content of SAN and in blend ratio was investigated by differential scanning calorimetry. For the melting points at a constant blend ratio occur a minimum in dependence on the copolymer composition for blends containing about 20 wt% acrylonitrile in SAN. From melting point depression data a negative, binary interaction parameter was obtained for PCL/SAN blends containing a SAN with 19.2 wt% AN. By optical microscopy it can be shown that the shape of the spherulites changes with copolymer composition of SAN and blend ratio.

The miscibility window of poly(methylmethacrylate)/poly(styrene- co-acrylonitrile) blends

The miscibility behaviour of poly(methylmethacrylate)/poly(styrene- co-acrylonitrile) (PMMA/SAN) blends with changes in blend ratio and acrylonitrile content of SAN was investigated by laser light scattering. The results show a miscibility window in the temperature versus copolymer composition plane. The phase morphology was observed over the whole copolymer composition and temperature area by light microscopy. A highly interconnected two-phase structure which occurs just above the lower critical solution temperature can also be found at room temperature in a certain region just outside the composition of the miscibility window. The differential scanning calorimetry trace of miscible systems displays a broadening at high PMMA contents in the blend.

Compatibility of poly(ϵ‐caprolactone) (PCL) and poly(styrene‐co‐acrylonitrile) (SAN) blends. II. The influence of the AN content in SAN copolymer upon blend compatibility

AbstractThe compatibility of polymer blends of poly(ϵ‐caprolactone) (PCL) and poly(styrene‐co‐acrylonitrile) (SAN) containing various acrylonitrile (AN) contents was studied to evaluate the influences of copolymer composition and PCL concentration upon blend compatibility. Blend compatibility was characterized by the occurence of a single glass transition intermediate between the transitions of the respective pure components. The glass transitions were determined by differential scanning calorimetry (DSC) and dynamic mechanical measurement (Rheovibron). It was found that SAN and PCL form compatible blends when the AN content of SAN ranges from 8% to 28% by weight. These blends are compatible in all proportions except for SAN 28 (AN wt % = 28) and PCL blends containing 70 or 85 wt % PCL. Blends of PCL and SAN were found to be incompatible when the AN content in SAN is greater than 30 wt % or less than 6 wt %. Lower critical solution temperature (LCST) behavior, which can be attributed to phase separation, was found to occur when these blends were heated to elevated temperatures. The cloud point, or phase separation, was found to vary with AN content in SAN and the concentration of SAN in the blend.