Blending of styrene‐block‐butadiene‐block‐styrene copolymer with sulfonated vinyl aromatic polymers

Different polymers containing sulfonic groups attached to the phenyl rings were prepared by sulfonation of polystyrene (PS) and styrene‐block‐(ethylene‐co‐1‐butene)‐block‐styrene (SEBS). The sulfonation degree (SD) was varied between 1 and 20 mol% of the styrene units. Polyphase materials containing sulfonated units were prepared by blending styrene‐block‐butadiene‐block‐styrene (SBS), with both sulfonated PS and sulfonated SEBS in a Brabender mixer. Such a procedure was performed as an alternative route to direct sulfonation of SBS which is actually not selective towards benzene rings because of the great reactivity of the double bonds in polybutadiene (PB) blocks to sulfonation agents. Thermal and dynamic‐mechanic analysis, together with morphology characterization of the blends, is consistent with obtaining partially compatible blends characterized by higher T_g of the polystyrene domains and improved thermal stability. © 2001 Society of Chemical Industry     

Domain structure and miscibility studies of blends of styrene–butadiene–styrene block copolymers (SBS) and styrene–glycidyl methacrylate statistical copolymers (PS‐GMA) using SAXS and DMTA

The domain structure and miscibility in the solid state of a series of blends of styrene‐butadiene‐styrene (SBS) block copolymers and styrene‐glycidyl methacrylate (PS‐GMA) statistical copolymers with varying molecular weights and compositions were studied using small angle X‐ray scattering and dynamic mechanical thermal analysis. Depending on the molecular characteristics of each component, different types and degrees of solubilization of PS‐GMA in SBS were found which, in addition to the initially SBS phase morphology, lead to materials with multiphase domain morphologies with differences in size and structure. The degree of solubilization of PS‐GMA into the PS domains of SBS was found to be higher for blends containing PS‐GMA with lower molecular weight (M_w = 18 100 g mol^?1) and lower GMA content (1 wt%) and/or for SBS with higher PS content (39 wt%) and longer PS blocks (M_w = 19 600 g mol^?1). Localized solubilization of PS‐GMA in the middle of PS domains of SBS was found to be the most probable to occur for the systems under study, causing swelling of PS domains. However, uniform solubilization was also observed for SBS/PS‐GMA blends containing SBS with composition in the range of a morphological transition (PS block M_w = 19 600 g mol^?1 and 39 wt% of PS) causing a morphological transition in the SBS copolymer (cylinder to lamella). Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Micro‐ and macrophase separation of thermosetting systems modified with epoxidized styrene‐block‐butadiene‐ block‐styrene linear triblock copolymers and their influence on final mechanical properties

BACKGROUND: The goal of this work was to establish the minimum degree of epoxidation needed to develop nanostructured epoxy systems by modification with poly(styrene‐block‐butadiene‐block‐styrene) (SBS) triblock copolymers epoxidized to several degrees, and also to investigate the effect of polystyrene (PS) content on the final morphologies. By using two SBS copolymers, the influence of the weight ratio of the two blocks on the generated morphologies and mechanical properties was also analysed. RESULTS: Nanostructured thermosets were effectively obtained through reaction‐induced microphase separation of PS blocks from the matrix. A minimum of 27 mol% of epoxidation, which corresponds to 4.8 wt% of epoxidized polybutadiene (PB) units in the overall mixture, was needed to ensure nanostructuring of final mixtures and thus their transparency. Hexagonally ordered nanostructures were achieved for PS contents of around 16–20 wt%, which agrees with our previous results for mixtures with other SBS copolymers with different ratios between blocks. The fracture toughness of the epoxy matrix was improved or at least retained with mixing. CONCLUSION: The degree of epoxidation of PB blocks needed to switch epoxy/SBS mixtures from a macrophase‐separated to a nanostructured state has been established. The generated morphologies in the epoxy systems are mainly dependent on the PS content in the mixture. Copyright © 2008 Society of Chemical Industry     

The mechanical properties of styrene-butadiene-styrene (SBS) triblock copolymer blends with polystyrene (PS) and styrene-butadiene copolymer (SBR)

Measurements were made of linear viscoelastic properties and nonlinear stress-strain properties of phase-separated styrene-butadiene-styrene (SBS) copolymers and their blends with several homopolymer polystyrenes (PS) and one random copolymer (SBR). Torsion pendulum testing yielded shear moduli G′, G″, and Rheovibron experiments produced tensile moduli E′, E″, over a 220°K range of temperature, both at low frequencies. For pure copolymers and their PS blends, G′ and E′ correlated quite well with the total PS content, but G″ and E″ were more sensitive to how the additive was distributed. Results suggest that a PS additive whose molecular weight (M) is less than that of the copolymer PS-block (M_s) causes expansion of both the interphase and the homogeneous PS-rich phase, while an additive with M > M_s mixes less well with these phases (probably forming separate domains of pure PS) and is less effective in enhancing the linear moduli. The blending with SBB produced reduction in G′ but a broad midrange peak in G″, suggesting that SBR was localized almost entirely within an expanded interphase. Tensile stress-strain data were obtained with an Material Testing System at room temperature. For PS blends, properties did not correlate well with the total PS content, the blends being always weaker than the SBS of the same overall composition. The amount of set also increased with PS content in the blends. Cyclic tests to increasing strain showed progressive structural alterations (as for the host SBS), with blend behavior resembling host properties more closely with each new cycle. When SBR was the additive, amounts as small as 1 percent reduced the curves by 15 percent. The yield stress was eliminated entirely with an addition of 10 percent SBR, but for all cases the set was the same. Results are discussed in terms of interphase force barriers to chain flow.     

Storage modulus of polybutadiene core in acrylonitrile–butadiene–styrene polymers with different degrees of grafting

The linear viscoelastic behavior of acrylonitrile‐butadiene‐styrene (ABS) polymers in the molten state, with different degrees of grafting, was investigated within the framework of Palierne's emulsion model. The main aim of the present study is to quantitatively analyze the effect of grafting degree on the storage modulus G′ of the polybutadiene (PB) rubber core dispersed in ABS polymers. According to our model calculations, the degree of grafting significantly affects the G′ values of the PB core and, hence, the viscoelastic properties of ABS polymers. Our calculations showed that the Palierne model is very useful to calculate the storage modulus of the rubber particles dispersed in rubber‐modified polymeric materials, at least in the high‐frequency region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 924–930, 2001     

A modified rheological model of viscosities for BR–SBS blends

Blends of polybutadiene (BR) and styrene–butadiene–styrene triblock copolymer (SBS) have been prepared by a two‐roll mill. The morphologies of extruded samples from a capillary rheometer were observed by scanning electron microscopy (SEM). It is found that PS phase is dispersed in the BR phase. The glass transition temperature (T_g) of the blend has been examined by using differential scanning calorimetry (DSC). From the T_g behavior and the electron microscopy study, it is found that certain degree of miscibility between the polystyrene phase and the BR phase is observed. The rheological behavior of the blend has been investigated by a capillary rheometer. It is found that the viscosity of the blend increases with increased content of PS phase. The behavior is in accord with the expected behavior of filler effect. To predict the filler effect of PS phase on the BR–SBS blend, a modified model of Chen and Cheng is proposed to elucidate the rheological properties of the BR–SBS blends with different compositions. Chen and Cheng's micromechanical model derived in Part I of this series, which relates the macroscopic shear stress to the macroscopic shear rate of a rigid non‐Newtonian suspension when the direct contribution of Brownian force is completely neglected. The agreement between the theoretical predictions and the experimental results is satisfactory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 39–46, 1999     

Effects of the molecular structure of impact modifier and compatibilizer on the toughening of PBT/SBS/PS‐GMA blends

This work aims at studying the toughening process of poly(butylene terephthalate) (PBT) through its blends with styrene‐butadiene‐styrene block copolymers (SBS), in the presence of poly(styrene‐ran‐glicydil methacrylate) (PS‐GMA) as reactive compatibilizer. High values of impact strength were attained for PBT/SBS blends without the compatibilizer; however, this improvement is achieved for blends with SBS having similar viscosity compared to PBT, at high SBS content (40 wt %) and for blends prepared under specific processing conditions. The efficiency of the in situ compatibilization of PBT/SBS blends by PS‐GMA was found to be strongly dependent on the SBS and PS‐GMA molecular characteristics. Better compatibilizing results were observed through fine phase morphologies and lower ductile to brittle transition temperatures (DBTT) as the interfacial interaction and stability of the in situ formed compatibilizer are maximized, that is, when the miscibility between SBS and PS‐GMA and reaction degree between PBT and PS‐GMA are maximized. For the PBT/SBS/PS‐GMA blends under study, this was found when it is used the SBS with higher polystyrene content (38 wt %) and with longer PS blocks (M_w = 20,000 g mol^?1) and also the PS‐GMA with moderate GMA contents (4 wt %) and with molecular weight similar to the critical one for PS entanglements (M_c = 35,000 g mol^?1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5795–5807, 2006     

Influence of core–shell rubber particles synthesized with different initiation systems on the impact toughness of modified polystyrene

Core–shell poly(butadiene‐graft‐styrene) (PB‐g‐PS) rubber particles were synthesized with different initiation systems by emulsion grafting polymerization. These initiation systems included the redox initiators and an oil‐soluble initiator, 1,2‐azobisisobutyronitrile (AIBN). Then the PB‐g‐PS impact modifiers were blended with polystyrene (PS) to prepare the PS/PB‐g‐PS blends. In the condition of the same tensile yield strength on both samples, the Izod test showed that the notched impact strength of PS/PB‐g‐PS(AIBN) was 237.8 J/m, almost 7 times than that of the PS/PB‐g‐PS(redox) blend, 37.2 J/m. From transmission electron microscope (TEM) photographs, using the redox initiators, some microphase PS zones existed in the core of PB rubber particles, which is called “internal‐grafting.” This grafting way was inefficient on toughening. However, using AIBN as initiator, a great scale of PS subinclusion was seen within the PB particle core, and this microstructure increased the effective volume fraction of the rubber phase with a result of improving the toughness of modified polystyrene. The dynamic mechanical analysis (DMA) on both samples showed that the glass transition temperature (T_g) of rubber phase of PS/PB‐g‐PS(AIBN) was lower than that of PS/PB‐g‐PS(redox). As a result, the PB‐g‐PS(AIBN) had better toughening efficiency on modified polystyrene than the PB‐g‐PS(redox), which accorded with the Kerner approximate equation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 738–744, 2007     

Grafting of maleic anhydride onto styrene–butadiene–styrene triblock copolymer using supercritical CO2 as a swelling agent

Grafting of maleic anhydride (MA) onto styrene–butadiene–styrene triblock copolymer (SBS) was carried out by free radical polymerization using supercritical carbon dioxide (SC CO₂) as a solvent of MA and swelling agent of SBS. The effect of various factors such as monomer concentration, initiator concentration, SC CO₂ pressure, and reaction time on grafting ratio was studied. SBS and the product (SBS‐g‐MA) were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). GPC data showed that the molecular weight of SBS‐g‐MA is bigger than that of SBS. DSC testing indicated that the glass transition temperature (T_g) of SBS‐g‐MA is higher than that of SBS. By SEM photo, we can observe that some particles which contain more oxygen atom grew out from the surface of SBS‐g‐MA when grafting ratio reached at 5.6%, and the amount and diameter of particles increased with increasing of grafting ratio. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4425–4429, 2006     

Mechanical and piezo‐resistive properties of styrene–butadiene–styrene copolymer covalently modified with graphene/styrene–butadiene–styrene composites

As novel piezoelectric materials, carbon‐reinforced polymer composites exhibit excellent piezoelectric properties and flexibility. In this study, we used a styrene–butadiene–styrene triblock copolymer covalently grafted with graphene (SBS‐g‐RGO) to prepare SBS‐g‐RGO/styrene–butadiene–styrene (SBS) composites to enhance the organic solubility of graphene sheets and its dispersion in composites. Once exfoliated from natural graphite, graphene oxide was chemically modified with 1,6‐hexanediamine to functionalize with amino groups (GO–NH₂), and this was followed by reduction with hydrazine [amine‐functionalized graphene oxide (RGO–NH₂)]. SBS‐g‐RGO was finally obtained by the reaction of RGO–NH₂ and maleic anhydride grafted SBS. After that, X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and other methods were applied to characterize SBS‐g‐RGO. The results indicate that the SBS molecules were grafted onto the graphene sheets by covalent bonds, and SBS‐g‐RGO was dispersed well. In addition, the mechanical and electrical conductivity properties of the SBS‐g‐RGO/SBS composites showed significant improvements because of the excellent interfacial interactions and homogeneous dispersion of SBS‐g‐RGO in SBS. Moreover, the composites exhibited remarkable piezo resistivity under vertical compression and great repeatability after 10 compression cycles; thus, the composites have the potential to be applied in sensor production. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46568.     

Styrene–butadiene block copolymer with high cis‐1,4 microstructure

The sequential block copolymerization of styrene (St) and butadiene (Bd) was carried out with an activated rare earth catalyst composed of catalyst neodymium tricarboxylate (Nd), cocatalyst Al(i‐Bu)₃ (Al), and chlorinating agent (Cl). The microstructure, composition, and morphology of the copolymer were characterized by FTIR, ¹H NMR, ¹³C NMR, and TEM. The results show that styrene–butadiene diblock copolymer with high cis‐1,4 microstructure of butadiene units (～ 97 mol %) was synthesized. The cis‐selectivity for Bd units was almost independent on the content of styrene units in the copolymer ranging from 18.1 mol % to 29.8 mol %. The phase‐separated morphology of polystyrene (PS) domains of about 40 nm tethered by the elastomeric polybutadiene (PB) segments is observed. The PS‐b‐cis‐PB copolymer could be used as an effective compatilizer for noncompatilized binary PS/cis‐PB blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and dynamic mechanical properties of poly(styrene‐b‐butadiene)‐modified clay nanocomposites

Polybutyl acrylate (PBA) was intercalated into clay by the method of multistep exchange reactions and diffusion polymerization. The clay interlayer surface is modified, and obtaining the modified clay. The structures of the clay‐PBA, clay‐GA (glutamic acid), and the clay‐DMSO (dimethyl sulfoxide) were characterized using X‐ray diffraction (XRD). The new hybrid nanocomposite thermoplastic elastomers were prepared by the clay‐PBA with poly(styrene‐b‐butadiene) block copolymer (SBS) through direct melt intercalation. The dynamic mechanical analysis (DMA) curves of the SBS/modified clay nanocomposites show that partial polystyrene segments of the SBS have intercalated into the modified clay interlayer and exhibited a new glass transition at about 157°C (T_g3). The glass transition temperature of polybutadiene segments (T_g1) and polystyrene segments out of the modified clay interlayer (T_g2) are about ?76 and 94°C, respectively, comparied with about ?79 and 100°C of the neat SBS, and they are basically unchanged. The T_g2 intensity of the SBS‐modified clay decreases with increasing the amounts of the modified clay, and the T_g3 intensity of the SBS‐modified clay decreases with increasing the amounts of the modified clay up to about 8.0 wt %. When the contents of the modified clay are less than about 8.0 wt %, the SBS‐modified clay nanocomposites are homogeneous and transparent. The T_gb and T_gs of the SBS‐clay (mass ratio = 98.0/2.0) are ?78.39 and 98.29°C, respectively. This result shows that the unmodified clay does not essentially affect the T_gb and T_gs of the SBS, and no interactions occur between the SBS and the unmodified clay. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1499–1503, 2002; DOI 10.1002/app.10353     

Rapid FTIR method for quantification of styrene‐butadiene type copolymers in bitumen

The mid‐IR molar absorptivity for polystyrene (PS) and polybutadiene (PB) blocks were obtained for five styrene‐butadiene‐styrene (SBS) and SB copolymers, including linear, branched, and star copolymers, and their blends with bitumen. The average absorptivity for PS and PB blocks was 277 and 69 L mol⁻¹ cm⁻¹ and it was little affected by the S/B ratio or the copolymer architecture. In the presence of bitumen, Beer's law was obeyed but the respective PS and PB absorptivity was 242 and 68 L mol⁻¹ cm⁻¹, possibly because of weak interactions between the copolymer and bitumen. The absorptivity values were used to calculate the concentration of SB‐type copolymers in blends with bitumen with an accuracy of 10% or better. The method can be used to probe the stability of bitumen–copolymer blends in storage at 165°C, to determine the copolymer concentration in commercial polymer modified bitumen (PMB), and to assess the resistance of PMB to weathering. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1034–1041, 2001     

Cell evolution and compressive properties of styrene–butadiene–styrene toughened and calcium carbonate reinforced polystyrene extrusion foams with supercritical carbon dioxide

Polystyrene (PS) foams have been used in various fields, whereas its broader application is limited by its low mechanical strength and brittle features. In this study, styrene–butadiene–styrene (SBS) and calcium carbonate (CaCO₃) nanoparticles were melt‐blended with PS and extrusion‐foamed with supercritical carbon dioxide as a blowing agent to simultaneously toughen and reinforce PS foams. Under the same foaming conditions, the addition of SBS and CaCO₃ was shown to have a significant influence on the cell structure and the compressive properties of the composite foams. We found that the cell structure evolution was highly correlated with the system viscosity. When the rubbery‐phase SBS content was 20%, the cell diameter decreased by 20.7%, and the compressive modulus was enhanced by 289.5%. With the further addition of 5% rigid CaCO₃ nanoparticles, the cell diameter was further reduced by 72.2% and the compressive modulus was improved by 379.2%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43508.     

Effect of styrene‐butadiene triblock copolymer structure on its compatibilization efficiency in PS/PB and PS/PP blends

Two styrene‐butadiene triblock copolymers differing in the length of their styrene blocks (40S‐60B‐40S and 10S‐60B‐10S) were used as compatibilizers for PS/PB (4/1) and PS/PP (4/1) blends. The supramolecular structure of the copolymers determined by small‐angle X‐ray scattering (SAXS), morphology of the blends using transmission electron microscopy (TEM), and their tensile impact strength were chosen as criteria of the compatibilization efficiency of the copolymers used. Different mechanisms of compatibilization for “symmetrical” system (PS/PB/SBS) and “asymmetrical” system (PS/PP/SBS) were proved. While for the PS/PB blend, the 40S‐60B‐40S copolymer proved to be a good compatibilizer, for the PS/PP blend, surprisingly, the 10S‐60B‐10S copolymer is more efficient.     

Transparent,fluorescent, and mechanical enhanced elastomeric composites formed with poly (styrene‐butadiene‐styrene) and SiO2‐hybridized CdTe quantum dots

Transparent poly(styrene‐butadiene‐styrene) (SBS)‐quantum dots (QDs) composites (SBS/CdTe QDs) that simultaneously possess strong photoluminescence (PL) and enhanced mechanical properties are presented for the first time based on the facile blending of SiO₂‐hybridized CdTe QDs with SBS. UV–vis spectrum and fluorescence measurement show that SBS/CdTe QDs composites exhibit good optical properties. The results of transmission electron microscopy show good dispersion of CdTe QDs in the SBS matrix. The results of dynamic mechanical thermal analysis indicate that the micro‐phase separated structure of the SBS is exist in the composites, and the presence of CdTe QDs can lead to an decrease of glass transition temperatures of polybutadiene (PB) and polystyrene(PS) domains. In addition, mechanical tests reveal that the addition of CdTe QDs is a useful approach to improve the mechanical properties of SBS. Meanwhile, the fluorescent photographs taken under ultraviolet light prove that SBS/CdTe QDs composites possess strong PL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Plasticization of nano‐CaCO3 in polystyrene/nano‐CaCO3 composites

The shear rheological properties of polystyrene (PS)/nano‐CaCO₃ composites were studied to determine the plasticization of nano‐CaCO₃ to PS. The composites were prepared by melt extrusion. A poly(styrene–butadiene–styrene) triblock copolymer (SBS), a poly(styrene–isoprene–styrene) triblock copolymer (SIS), SBS‐grafted maleic anhydride (SBS–MAH), and SIS‐grafted maleic anhydride were used as modifiers or compatibilizers. Because of the weak interaction between CaCO₃ and the PS matrix, the composites with 1 and 3 phr CaCO₃ loadings exhibited apparently higher melt shear rates under the same shear stress with respect to the matrix polymer. The storage moduli for the composites increased with low CaCO₃ concentrations. The results showed that CaCO₃ had some effects on the compatibility of PS/SBS (or SBS–MAH)/CaCO₃ composites, in which SBS could effectively retard the movement of PS chain segments. The improvement of compatibility, due to the chemical interaction between CaCO₃ and the grafted maleic anhydride, had obvious effects on the rheological behavior of the composites, the melt shear rate of the composites decreased greatly, and the results showed that nano‐CaCO₃ could plasticize the PS matrix to some extent. Rheological methods provided an indirect but useful characterization of the composite structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Effect of styrene–isoprene–styrene,styrene–butadiene–styrene,and styrene–butadiene–rubber on the mechanical,thermal, rheological,and morphological properties of polypropylene/polystyrene blends

The mechanical, thermal, rheological, and morphological properties of polypropylene (PP)/polystyrene (PS) blends compatibilized with styrene–isoprene–styrene (SIS), styrene–butadiene–styrene (SBS), and styrene–butadiene–rubber (SBR) were studied. The incompatible PP and PS phases were effectively dispersed by the addition of SIS, SBS, and SBR as compatibilizers. The PP/PS blends were mechanically evaluated in terms of the impact strength, ductility, and tensile yield stress to determine the influence of the compatibilizers on the performance properties of these materials. SIS‐ and SBS‐compatibilized blends showed significantly improved impact strength and ductility in comparison with SBR‐compatibilized blends over the entire range of compatibilizer concentrations. Differential scanning calorimetry indicated compatibility between the components upon the addition of SIS, SBS, and SBR by the appearance of shifts in the melt peak of PP toward the melting range of PS. The melt viscosity and storage modulus of the blends depended on the composition, type, and amount of compatibilizer. Scanning electron microscopy images confirmed the compatibility between the PP and PS components in the presence of SIS, SBS, and SBR by showing finer phase domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 266–277, 2003     

Dynamic mechanical properties of polystyrene‐block‐poly[ethylene‐co‐(ethylene‐propylene)]‐block‐polystyrene triblock copolymer/hydrocarbon oil blends

Blend systems of polystyrene‐block‐poly(ethylene‐co‐(ethylene‐propylene))‐block‐polystyrene (SEEPS) triblock copolymer with three types of hydrocarbon oil of different molecular weight were prepared. The E″ curves as a function of temperature exhibited two peaks; one peak at low temperature (? ?50°C), arising from the glass transition of the poly[ethylene‐co‐(ethylene‐propylene)] (PEEP) phase and a high temperature peak (? 100°C), arising from the glass transition of the polystyrene (PS) phase. The glass transition temperature (T_g) of the PEEP phase shifted to lower temperature with increasing oil content. The shifted T_g depended on the types of oil and was lower for the low molecular weight oil. The T_g of PS phase of the present blend system, were found to be constant and independent of the oil content, when molecular weight of the oil is high. However, for the lower molecular weight oil, the T_g of the PS phase also shifted to lower temperatures. This fact indicates that the oil of high molecular weight is merely dissolved in the PS phase. The E′ at (75°C, at which temperature both of PEEP and PS phases are in glassy state, was found to be independent of oil content. In contrast, at 25°C, at which temperature the PEEP phase is in rubbery state, the E′ decreased sharply with increasing oil content. This result indicates that the hydrocarbon oil was a selective solvent in the PEEP phase. It mainly dissolved in the PEEP phase, although slightly dissolved into the PS phase as well, when molecular weight of oil is low. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The study of poly(styrene‐co‐p‐(hexafluoro‐2‐hydroxylisopropyl)‐α‐methylstyrene)/poly(ethylene oxide) blends

Different hydroxyl content poly(styrene‐co‐p‐(hexafluoro‐2‐hydroxylisopropyl)‐α‐methylstyene) [PS(OH)‐X] copolymers were synthesized and blends with 2,2,6,6‐tetramrthyl‐piperdine‐1‐oxyl end spin‐labeled PEO [SLPEO] were prepared. The miscibility behavior of all the blends was predicted by comparing the critical miscible polymer–polymer interaction parameter (χ_crit) with the polymer–polymer interaction parameter (χ). The micro heterogeneity, chain motion, and hydrogen bonding interaction of the blends were investigated by the ESR spin label method. Two spectral components with different rates of motion were observed in the ESR composite spectra of all the blends, indicating the existence of microheterogeneity at the molecular level. According to the variations of ESR spectral parameters T_a, T_d, ΔT, T_50G and τ_c, with the increasing hydroxyl content in blends, it was shown that the extent of miscibility was progressively enhanced due to the controllable hydrogen bonding interaction between the hydroxyl in PS(OH) and the ether oxygen in PEO. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2312–2317, 2004