Upper critical solution temperature type phase behavior of poly(styrene‐co‐acrylonitrile) blends with poly(styrene‐co‐n‐phenyl maleimide) and their interaction energies

To enhance the heat resistance of poly(styrene‐co‐acrylonitrile‐co‐butadiene), ABS, miscibility of poly(styrene‐co‐acrylonitrile), SAN, with poly(styrene‐co‐n‐phenyl maleimide), SNPMI, having a higher glass transition temperature than SAN was explored. SAN/SNPMI blends casted from solvent were immiscible regardless of copolymer compositions. However, SNPMI copolymer forms homogeneous mixtures with SAN copolymer within specific ranges of copolymer composition upon heating caused by upper critical solution temperature, UCST, type phase behavior. Since immiscibility of solvent casting samples can be driven by solvent effects even though SAN/SNPMI blends are miscible, UCST‐type phase behavior was confirmed by exploring phase reversibility. When copolymer composition of SNPMI was fixed, the phase homogenization temperature of SAN/SNPMI blends was increased as AN content in SAN copolymer increased. To understand the observed phase behavior of SAN/SNPMI blend, interaction energies of blends were calculated from the UCST‐type phase boundaries by using the lattice‐fluid theory combined with a binary interaction model. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1131–1139, 2008     

Thermal behaviour of binary and ternary copolymers containing acrylonitrile

Three types of acrylonitrile copolymers (acrylonitrile-styrene-butadiene copolymer (ABS¹), acrylonitrile-styrene random copolymer (SAN²) and acrylonitrile-butadiene random copolymer (BAN³) were studied by thermogravimetry (TG/DTG⁴) and by pyrolysis in a semi-batch process at 450 °C in order to find structure–thermal behaviour relationships. The overlapped thermo-oxidative degradation processes were separated and the corresponding kinetic parameters were calculated. The TG/DTG studies have evidenced that the styrene-acrylonitrile interactions stabilize the nitrile groups reacting by chain scission rather than cyclization and destabilize the styrene units. Also, the cyclization of the acrylonitrile units in ABS is favoured by interactions with the styrene and butadiene units. The pyrolysis behaviour evidenced that the styrene-acrylonitrile interactions in SAN and ABS lead to the formation of 4-phenylbutyronitrile as the most important decomposition compound. ABS shows similar composition of the degradation oil with SAN copolymer therefore in the ABS the styrene-butadiene interactions are less important than those between styrene and acrylonitrile units.     

Intramolecular interactions in poly(styrene-co-acrylonitrile)/poly(ε-caprolactone) blends

Specific interactions in blends of poly(ε-caprolactone) (PCL) and poly(styrene-co-acry-lonitrile) (SAN) were studied as a function of copolymer composition and blend ratio by using Fourier-transform infrared spectroscopy (FTIR). It was shown that miscibility occurred within a certain range of copolymer compositions because the presence of PCL reduced the thermodynamically unfavorable repulsion between styrene and acrylonitrile segments in the random copolymer. This effect was observed in terms of a shift to higher frequencies in the 700 cm^-1 γ-CH out-of-plane deformation vibration absorption of styrene and in the approximately 2236 cm^?1 C?N stretching frequency band in acrylonitrile segments. Specific intermolecular interactions between SAN and PCL were not observed in this study. © 1993 John Wiley & Sons, Inc.     

聚碳酸酯与苯乙烯-丙烯腈共聚物共混体系相容性及其对光学性能的影响

利用分子内链段排斥性相互作用理论研究了聚碳酸酯 (PC) 苯乙烯 丙烯腈共聚物 (SAN)共混体系中组份分子量及SAN共聚比例对体系相容性的影响规律 ,确定了获得均相的PC SAN共混体系的条件 ,考察了体系相容性与光学性能之间的关系 .通过实验获得了均相的PC SAN共混物 ;研究结果表明PC聚合度为 90、SAN聚合度为 3 0的PC SAN(S体积含量为 68%)体系共混比在 60∶40附近时体系的双折射能够实现补偿 ,紫外透光率达到 70 %.     

An experimental study on saturation swelling of styrene–acryronitrile copolymer particles with styrene and acrylonitrile monomers

The saturation swelling behavior of styrene and acrylonitrile (SAN) copolymer particles with a styrene (St) and acrylonitrile (AN) comonomer mixture was investigated experimentally. The effects of the copolymer composition and the compositional inhomogeneity in SAN Copolymer particles on their swelling behavior were examined. The experimental results show that both the copolymer composition and the compositional inhomogeneity in SAN copolymer particles have little or no influence on the swellability of SAN copolymer particles with a St and AN comonomer mixture, as long as the weight fraction of AN monomer units in SAN copolymer particles is less than a certain value between 0.6 and 0.8. With increasing AN content in the copolymer particles beyond this value, however, the swellability of SAN copolymer particles gradually decreases. Semiempirical equations are proposed, which correlate the saturation concentration of each monomer in SAN copolymer particles as a function of the comonomer composition in the monomer droplets and the overall copolymer composition in SAN copolymer particles. © 1994 John Wiley & Sons, Inc.     

The influence of the arrangement of styrene in methyl methacrylate/butadiene/styrene on the properties of PMMA/SAN/MBS blends

A series of methyl methacrylate‐butadiene‐styrene (MBS) core–shell impact modifiers were prepared by grafting styrene (St) and methyl methacrylate (MMA) onto polybutadiene (PB) or styrene‐butadiene rubber (SBR) seed latex in emulsion polymerization. All the MBS modifiers were designed to have the same total chemical composition, and Bd/St/MMA equaled 39/31/30, which was a prerequisite for producing transparent blends with poly(MMA)/styrene‐acrylonitrile (PMMA/SAN) matrix copolymers. Under this composition, different ways of arrangement for styrene in MBS led to the different structure of MBS modifier. The concentration of PB or SBR rubber of MBS in PMMA/SAN/MBS blends was kept at a constant value of 15 wt.%. The effects of arrangement of St in MBS on the mechanical and optical properties of PMMA/SAN/MBS blends were investigated. The results indicated that Izod impact strength of PMMMA/SAN/MBS blend with the amount of St grafted on core in MBS was higher than that of blend with the amount of St copolymerized with Bd in core of MBS, while the transparency of blend is opposite. From transmission electron microscopy, it was found that the arrangement of St in MBS influenced the dispersion of blend, which led to different toughness. Copyright © 2013 John Wiley & Sons, Ltd.     

Miscibility of poly(vinyl chloride) with styrene/acrylonitrile copolymers

Poly(vinyl chloride) (PVC) is shown to be miscible with styrene/acrylonitrile copolymers (SAN) having AN compositions from 11.5 to 26%. Blend samples were prepared using several methods, including solution casting, melt mixing, and precipitation of solutions by a nonsolvent. It is shown that the blend phase behavior is affected by preparation method due to the solvent effect, or Δ_χ effect, and lower critical solution temperature (LCST) behavior. The intramolecular repulsion between styrene and acrylonitrile units in SAN is shown to be the cause of miscibility using heats of mixing obtained from low-molecular-weight analog compounds. An FTIR analysis supplements the above results.     

Morphology and grafting reactions in core/shell latexes

The particle morphology and percent grafting were investigated as a function of the crosslink density of the seed latex in two systems of core/shell latexes of polybutadiene/polymethyl methacrylate (PB/PMMA) and styrene–butadiene rubber/polymethyl methacrylate (SBR/PMMA) prepared by seeded emulsion polymerization at 50°C. The thin layer chromatography/flame ionization detection (TLC/FID) technique was used to characterize the grafting efficiency of the core/shell latexes. The percent grafting of the shell polymer was found to decrease with increasing the crosslink density of the core material. The particle morphology and precent grafting were also investigated as a function of composition and structure of the core material in four core/shell latex systems: polybutadiene/styrene–acrylonitrile copolymer (PB/SAN), (styrene-butadiene) random copolymer/styrene acrylonitrile copolymer (S:B/SAN), polystyrene : polybutadiene/styrene-acrylonitrile copolymer (PS:PB/SAN) and Kraton/styrene-acrylonitrile copolymer (Kraton/SAN), which were prepared by direct emulsification for the seed followed by emulsion polymerization at 70°C for the shell polymer. Grafting and crosslinking of the core material were found to be competitive reactions depending on the microstructure of the seed latex.     

Effect of PBT molecular weight and reactive compatibilization on the dispersed‐phase coalescence of PBT/SAN blends

Poly(butylene terephthalate) (PBT)/styrene‐acrylonitrile copolymer (SAN) blends were investigated with respect to their phase morphology. The SAN component was kept as dispersed phase and PBT as matrix phase and the PBT/SAN viscosity ratio was changed by using different PBT molecular weights. PBT/SAN blends were also compatibilized by adding methyl methacrylate‐co‐glycidyl methacrylate‐co‐ethyl acrylate terpolymer, MGE, which is an in situ reactive compatibilizer for melt blending. In noncompatibilized blends, the dispersed phase particle size increased with SAN concentration due to coalescence effects. Static coalescence experiments showed evidence of greater coalescence in blends with higher viscosity ratios. For noncompatibilized PBT/SAN/MGE blends with high molecular weight PBT as matrix phase, the average particle size of SAN phase does not depend on the SAN concentration in the blends. However noncompatibilized blends with low molecular weight PBT showed a significant increase in SAN particle size with the SAN concentration. The effect of MGE epoxy content and MGE molecular weight on the morphology of the PBT/SAN blend was also investigated. As the MGE epoxy content increased, the average particle size of SAN initially decreased with both high and low molecular weight PBT phase, thereafter leveling off with a critical content of epoxy groups in the blend. This critical content was higher in the blends containing low molecular weight PBT than in those with high molecular weight PBT. At a fixed MGE epoxy content, a decrease in MGE molecular weight yielded PBT/SAN blends with dispersed nanoparticles with an average size of about 40 nm. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Reactive compatibilization of SAN/EPR blends: effect of the kinetics of the compatibilization reaction on the interfacial adhesion

The very poor adhesion between films of styrene and acrylonitrile random copolymer (SAN) and maleic anhydride grafted polypropylene (PP‐g‐MA) can be dramatically improved by an intermediate thin layer of SAN bearing groups reactive toward maleic anhydride. The rate of the interfacial reaction, which is controlled by the reactive groups attached to SAN (amine vs. carbamate) and by the method used to build up the sandwich assembly, has a decisive effect on the capability of the SAN‐g‐PP graft copolymer formed at the interface to improve the fracture toughness in direct dependence on its molecular architecture.     

Co‐continuous Polyamide 6 (PA6)/Acrylonitrile‐Butadiene‐Styrene (ABS) Nanocomposites

Summary: Polyamide 6 (PA6)/acrylonitrile‐butadiene‐styrene (ABS) (40/60 w/w) nanocomposites with a novel morphology were prepared by the melt mixing of PA6, ABS and organoclay. The blend nanocomposites had a co‐continuous structure, in which both PA6 and styrene‐acrylonitrile (SAN) were continuous phases. It was found that the toughening rubber particles were only located in the SAN phase and the strengthening clay platelets were selectively dispersed in the PA6 phase. The co‐continuous nanocomposites showed greatly improved mechanical properties over the whole temperature range when compared with the same blend sample without clay.

Schematic diagram for the co‐continuous ABS/PA6 blend nanocomposite.     

Synthesis of SAN‐containing block copolymers using RAFT polymerization

Copolymerization of styrene and acrylonitrile was carried out via reversible addition‐fragmentation chain transfer process (RAFT) in the presence of cumyl dithiobenzoate with AIBN as initiator. Copolymerization proceeded in a controlled/“living” fashion, and the copolymer composition depended on the feed ratio of monomer pairs. Block copolymers comprising styrene and acrylonitrile (SAN) segments and various functional blocks were synthesized through chain extension using the first blocks as macromolecular chain transfer agents (macroCTAs). Since the polymerization of both blocks proceeded through the RAFT process, the resulting block copolymers exhibited relatively narrow molecular weight distribution, with polydispersity indices in the range of 1.29–1.46. Gel permeation chromatography (GPC), and ¹H NMR and FTIR measurements confirmed the successful synthesis of the functionalized block copolymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2260–2269, 2006     

Miscibility of poly(ϵ-caprolactone) and of poly(styrene-co-acrylonitrile) with poly(styrene-co-acrylic acid)

The miscibility of poly (?-caprolactone) (PCL) with poly (styrene-co-acrylic acid) (SAA) and of poly (styrene-co-acrylonitrile) (SAN) with SAA was examined as a function of the comonomer composition in the copolymers. For PCL/SAA blends it was found that PCL is miscible with SAA within a specific range of copolymer compositions. Segmental interaction energy densities were evaluated by analysis of the equilibrium melting point depression and application of a binary interaction model. The results suggest that the intramolecular repulsion in SAA copolymer plays an important role in inducing the miscibility. Additionally, the critical AA content in SAA for the blend to be homogeneous was predicted by correlating the segmental interaction energy densities with the binary interaction model. For SAN/SAA blends, it was also found that SAA is miscible with SAN within a specific range of copolymer compositions. From the binary interaction model, segmental interaction energy denisties between different monomer units were estimated from the miscibility map and were found to be positive for all pairs, indicating that the miscibility of the blends is due to the strong repulsion in the SAA copolymers.     

Shear flow effect on phase behavior and morphology in polymer blends

The effect of simple shear flow on the phase behavior and morphology was investigated for both polystyrene/poly(vinyl methyl ether) (PS/PVME) and poly(methyl methacrylate)/poly(styrene‐co‐acrylonitrile) (PMMA /SAN‐29.5) blends, which have LCST (lower critical solution temperature)‐type phase diagram. The measurements were carried out using a special shear apparatus of two parallel glass plates type. The PS/PVME blends showed shear‐induced demixing and shear‐induced mixing at low and high shear rate values, respectively. In addition, the rotation speed and the sample thickness were found to have a pronounced effect on the phase behavior under shear flow. On the‐other hand, PMMA/SAN blend showed only shear‐induced mixing and the magnitudes of the elevation of the cloud points were found to be composition and molecular weight dependent. The morphology of the PMMA/SAN=75/25 blend indicated that shear‐induced mixing occurred at a critical shear rate value, below which the two phases were highly oriented and elongated in the flow direction.     

High Resolution Tip Enhanced Raman Mapping on Polymer Thin Films

Advanced tip enhanced Raman mapping (TERM) was applied to high resolution chemical identification on nanoscale. Thin poly(methyl methacrylate)/poly(styrene acrylonitrile) (SAN28/PMMA) blend films were measured at different stages of phase separation. New insights into the phase evolution behavior of the thin films were obtained, when the TERM images were compared. An unexpected morphology transition was observed after a few minutes annealing at 250 °C. No surface enrichment of PMMA was observed, differing from the previous reports on a similar well-studied system of SAN33/PMMA. The glass transition temperature, the surface and interfacial tension were found to be the main factors responsible for the phase evolution behavior of SAN28/PMMA films.     

Homopolymers and copolymers of acrylates and methacrylates of homoterpenylmethyl carbinol and α-campholenol

Acrylates and methacrylates of homoterpenylmethyl carbinol and α-campholenol were homopolymerized. Copolymers with each other and acrylonitrile were studied. Terpolymers of the acrylate of homoterpenylmethyl carbinol and the acrylate of α-campholenol with butadiene and styrene or acrylonitrile were also prepared. The lactone ring in the homopolymer of methacrylate of homoterpenylmethyl carbinol was opened up under basic conditions at room temperature, yielding a water-soluble polymer. Films of this polymer were cast from a water solution. The acrylate of homoterpenylmethyl carbinol gave a high molecular weight copolymer with acrylonitrile which could be molded into a transparent, extremely tough, film. The terpolymers of the acrylate of homoterpenylmethyl carbinol with butadiene and styrene or acrylonitrile were obtained in high yield and could be molded into strong, rubbery films. Several polymers were epoxidized and cured with p-phenylenediamine.     

Blend formation between homo- and co-polymers at 298.15 k,PMMA-SAN blends

Solution heats in chloroform at 25 °C have been measured experimentally for poly(methylmethacrylate) (PMMA), samples of poly(styrene-co-acrylonitrile) (SAN) containing from 5 to 37 mass% of acrylonitrile, and some PMMA-SAN blends prepared inside the miscibility range. From these data the mixing enthalpies for blend formation were obtained. Use of the mixing heats values in the framework of the Prigogine-Flory-Patterson theory allowed to calculate values of the exchange energy parameters between the components of the blends much more negative than existing literature data. Calculation of binary interaction energy parameters between the single repeat units of the copolymer from the above data, and from model compounds, clearly indicates a strong increase of the intramolecular repulsive energy between nitrile and styrene units of SAN, as compared with the interaction between the corresponding free model molecules. This revised version was published online in July 2006 with corrections to the Cover Date.     

Morphology of PC/SAN blends: effect of reactive compatibilization,SAN concentration,processing, and viscosity ratio

This article examines the effects of dispersed phase concentration, processing apparatus, viscosity ratio, and interfacial compatibilization using an SAN–amine compatibilizer on the morphology of blends of bisphenol A–polycarbonate (PC) with styrene–acrylonitrile (SAN) copolymers. For uncompatibilized blends, the dispersed phase particle size increased significantly with SAN concentration, and was found to exhibit a minimum at a viscosity ratio of approximately 0.35 for a fixed concentration of 30% SAN in the blend. Although the morphology of uncompatibilized PC/SAN blends mixed in a Brabender mixer, single‐ and twin‐screw extruders were quite similar, the twin‐screw extruder produced significantly finer morphologies in blends containing SAN–amine. The average particle size for blends compatibilized with the SAN–amine polymer was approximately half that of uncompatibilized blends and was relatively independent of viscosity ratio and dispersed phase composition. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 71–82, 1999     

Thermodynamic characterization of polymer‐polymer interfaces

The properties of multiphase polymer blends are determined in part by the nature of the polymer‐polymer interface. The interfacial tension, γ, influences morphology development during melt mixing while interfacial thickness, λ, is related to the adhesion between the phases in the solid blend. A quantitative relation between the thermodynamic interaction energy and these interfacial properties was first proposed in the theory of Helfand and Tagami and has since been correlated with experimental measurements with varying degrees of success. This paper demonstrates that the theory and experiment can be unified for polymer pairs of some technological importance: copolymers of styrene and acrylonitrile (SAN) with poly (2, 6‐dimethyl‐1, 4‐phenylene oxide) (PPO) and with bisphenol‐A polycarbonate (PC). For each pair, the overall interaction energy was calculated using a mean‐field binary interaction model expressed in terms of the interactions between repeat unit pairs extracted from blend phase behavior. Predictions of γ and λ as a function of copolymer composition made by combining the binary interaction model with the Helfand‐Tagami theory compare favorably with experimental measurements.     

Evaluation of the interaction parameter for poly(ε‐caprolactone)/poly(styrene‐co‐acrylonitrile) blends

In this article, the miscibility of poly(ε‐caprolactone) (PCL) with poly(styrene‐co‐acrylonitrile) (SAN) containing 25 wt % of acrylonitrile is studied from both a qualitative and a quantitative point of view. The evidences coming from thermal analysis (differential scanning calorimetry) demonstrate that PCL and SAN are miscible in the whole range of composition. The Flory interaction parameter χ_1,2 was calculated by the Patterson approximation and the melting point depression of the crystalline phase in the blends; in both cases, negative values of χ_1,2 were found, confirming that the system is miscible. The interaction parameter evaluated within the framework of the mean field theory demonstrates that the miscibility of PCL/SAN blends is due to the repulsive interaction between the styrene and acrylonitrile segments in SAN. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010