Nonlinear phase‐separation behavior of poly(methyl methacrylate)/poly(styrene‐co‐maleic anhydride) blends

The nonlinear phase‐separation behavior of poly(methyl methacrylate)/poly(styrene‐co‐maleic anhydride) (PMMA/SMA) blends over wide appropriate temperature and heating rate ranges was studied using time‐resolved small‐angle laser light scattering. During the non‐isothermal process, a quantitative logarithm function was established to describe the relationship between cloud point (T_c) and heating rate (k) as given by T_c = Alnk + T₀, in which the parameter A, reflecting the heating rate dependence, is much different for different compositions due to phase‐separation rate and activation energy difference. For the isothermal phase‐separation process, an Arrhenius‐like equation was successfully applied to describe the temperature dependence of the apparent diffusion coefficient (D_app) and the relaxation time (τ) of the early stage as well as the late stage of spinodal decomposition (SD) of PMMA/SMA blends. Based on the successful application of the Arrhenius‐like equation, the related activation energies could be obtained from D_app and τ of the early and late stages of SD, respectively. In addition, these results indicate that it is possible to predict the temperature dependence of the phase‐separation behavior of binary polymer mixtures during isothermal annealing over a range of 100 °C above the glass transition temperature using the Arrhenius‐like equation. © 2012 Society of Chemical Industry     

Effects of blending on the molecular dynamics of highly interacting binary polymer blends of poly(methyl methacrylate) and poly[styrene‐co‐(maleic anhydride)]

The molecular dynamics and miscibility of highly interacting binary polymer blends of poly(methyl methacrylate) (PMMA) and poly[styrene‐co‐(maleic anhydride)] random copolymer with 8 wt% maleic anhydride content (SMA) were investigated as a function of composition over a wide range of frequency (10^?2–10⁶ Hz) at different constant temperatures (30–160 °C). Only one common glass relaxation process (α‐process) was detected for all measured blends, and its dynamics and broadness were found to be composition dependent. The existence of only one common α‐relaxation process located at a temperature range between those of the pure polymer components indicated the miscibility of the two polymer components over the entire range of composition. The miscibility was also confirmed by measuring the glass transition temperatures of the blends, T_g, using differential scanning calorimetry. The composition dependence of T_g of the blends showed a positive deviation from the linear mixing rule and well described by the Gordon–Taylor–Kwei equation. The relaxation spectrum of the blends was resolved into α‐ and β‐relaxation processes using the Havriliake–Negami (HN) equation and ionic conductivity. The dielectric relaxation parameters obtained from HN analysis, such as broadness of relaxation processes, maximum frequency, f_max, and dielectric strength, Δ? (for the α‐ and β‐relaxation processes), were found to be blend composition dependent. The kinetics of the α‐relaxation process of the blends were well described by the Meander model, while an Arrhenius‐type equation was used to evaluate the molecular dynamics of the β‐relaxation process. Blending of PMMA and SMA was found to have a considerable effect on the kinetics and broadness of the β‐relaxation process of PMMA, indicating that the strong interaction and miscibility between the two polymer components could effectively change the local environment of each component in the blend. © 2013 Society of Chemical Industry     

Investigation on the miscibility of the blends of poly(methyl methacrylate) and poly(styrene‐co‐acrylonitrile)

The miscibility was investigated in blends of poly(methyl methacrylate) (PMMA) and styrene‐acrylonitrile (SAN) copolymers with different acrylonitrile (AN) contents. The 50/50 wt % blends of PMMA with the SAN copolymers containing 5, 35, and 50 wt % of AN were immiscible, while the blend with copolymer containing 25 wt % of AN was miscible. The morphologies of PMMA/SAN blends were characterized by virtue of scanning electron microscopy and transmission electron microscopy. It was found that the miscibility of PMMA/SAN blends were in consistence with the morphologies observed. Moreover, the different morphologies in blends of PMMA and SAN were also observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(styrene‐co‐acrylonitrile)

Isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMAs) (designated as iPMMA, aPMMA, and sPMMA) with approximately the same molecular weight were mixed separately with poly(styrene‐co‐acrylonitrile) (abbreviated as PSAN) containing 25 wt % of acrylonitrile in tetrahydrofuran to make three polymer blend systems. Differential scanning calorimetry (DSC) was used to study the miscibility of these blends. The results showed that the tacticity of PMMA has a definite impact on its miscibility with PSAN. The aPMMA/PSAN and sPMMA/PSAN blends were found to be miscible because all the prepared films were transparent and showed composition dependent glass transition temperatures (T_gs). The glass transition temperatures of the two miscible blends were fitted well by the Fox equation, and no broadening of the glass transition regions was observed. The iPMMA/PSAN blends were found to be immiscible, because most of the cast films were translucent and had two glass transition temperatures. Through the use of a simple binary interaction model, the following comments can be drawn. The isotactic MMA segments seemed to interact differently with styrene and with acrylonitrile segments from atactic or syndiotactic MMA segments. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2894–2899, 1999     

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     

Ionomeric blends of poly(ethylene oxide) with poly(styrene‐co‐maleic anhydride) ionomer: Miscibility,crystallization, and melting behavior

The miscibility and crystallization behavior of poly(ethylene oxide) (PEO) and poly(styrene‐co‐maleic anhydride) ionomer (SMAI) blends were studied by the dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). This study has demonstrated that the presence of ion–dipole interactions enhances the miscibility of otherwise immiscible polymers in the PEO and high molecular weight poly(styrene‐co‐maleic anhydride) (SMA). The effect of ion–dipole interactions on enhancing miscibility is confirmed by the presence of a single glass transition temperature (T_g) and a depression of the equilibrium melting temperature of the PEO component. The equilibrium melting temperature of PEO in the blends are obtained using Hoffman‐Weeks plots. The interaction energy density, β, is calculated from these data using the Nishi‐Wang equation. The results suggest that PEO and SMAI blends are thermodynamically miscible in the melt. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1–7, 2000     

Polymer blends of stereoregular poly(methyl methacrylate) and poly(styrene‐co‐p‐hydroxystyrene)

Isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMAs) (designated as iPMMA, aPMMA, and sPMMA) were mixed with poly(styrene‐co‐p‐hydroxystyrene) (abbreviated as PHS) containing 15 mol % of hydroxystyrene separately in 2‐butanone to make three polymer blend systems. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to study the miscibility of these blends. The three polymer blends were found to be miscible, because all the prepared films were transparent and there was a single glass transition temperature (T_g) for each composition of the polymers. T_g elevation (above the additivity rule) is observed in all the three PMMA/PHS blends mainly because of hydrogen bonding. If less effective hydrogen bonding based on the FTIR evidence is assumed to infer less exothermic mixing, sPMMA may not be miscible with PHS over a broader range of conditions as iPMMA and aPMMA. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 431–440, 1999     

Molecular simulation of miscibility of poly(2,6‐dimethyl‐1,4‐phenylene ether)/poly(styrene‐co‐acrylonitrile) blend with the compatibilizer triblock terpolymer SBM

Polymer blend of poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE) and poly(styrene‐co‐acrylonitrile) (SAN), which has broad commercial interest, has limited miscibility. A triblock terpolymer, polystyrene‐block‐polybutadiene‐block‐poly(methyl methacrylate) (SBM), is often used as compatibilizer to improve the miscibility of PPE/SAN. In this work, dissipative particle dynamics and molecular dynamics of Material Studio were used to study the essentials that influence miscibility of the blend systems, and then Flory–Huggins parameter χ, radial distribution function (RDF) and morphologies are analyzed. It shows that the blends with more content of styrene in SAN (above 90 wt%), whose mass percentage is 60%, are best miscible. For the systems of PPE/SAN added with SBM, the miscibility increases and then decreases with the increase of SBM content. A longer chain of styrene (S) in SBM leads to wrapped structure of PMMA by PB, wrapped by PS, resulting in decrease of the miscibility. From studies and simulation of χ and RDF, the best blend system for commercial and industrial use is the one with mass ratio of PPE/SAN/SBM 36/54/10, in which S content in SAN is above 90 wt%. For SBM, the ratio of chain length styrene (S)/butadiene (B) is lessthan 1, while B and M are the same in chain length. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Direct polymer reaction of poly(styrene‐co‐maleic anhydride): Polymeric imidization

Using direct polymer reaction of poly(styrene‐co‐maleic anhydride) (SMA), a synthesis of copolymer of styrene and N‐aryl succinimide (SMI) has been investigated. SMI copolymers were synthesized from SMA copolymers by a concerted two‐step reaction, which consisted of the condensation reaction (step 1) of SMA with aromatic amine to prepare a precursor, succinamic acid, for imide formation and the cyclodehydration reaction (step 2) of succinamic acid. In this article, the application of Searle's preparation method of N‐aryl or N‐alkyl maleimide to the direct polymer reaction for SMI was attempted. Compared with synthesis of monomeric imides, the imide formation in polymeric condition appeared to be a little more sensitive to the reaction condition. The optimum condition for maximum conversion was examined in terms of time, temperature, and the amount of reactants. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1187–1196, 1999     

Blending poly(methyl methacrylate) and poly(styrene‐co‐acrylonitrile) as composite polymer electrolyte

A blend of poly(methyl methacrylate) (PMMA) and poly(styrene‐co‐acrylonitrile) (PSAN) has been evaluated as a composite polymer electrolyte by means of differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, ac impedance measurements, and linear sweep voltammetry (LSV). The blends show an interaction with the Li⁺ ions when complexed with lithium perchlorate (LiClO₄), which results in an increase in the glass‐transition temperature (T_g) of the blends. The purpose of using PSAN as another component of the blend is to improve the poor mechanical properties of PMMA‐based plasticized electrolytes. The mechanical property is further improved by introducing fumed silica as inert filler, and hence the liquid electrolyte uptake and ionic conductivity of the composite systems are increased. Room‐temperature conductivity of the order of 10^?4 S/cm has been achieved for one of the composite electrolytes made from a 1/1 blend of PSAN and PMMA containing 120% liquid electrolyte [1M LiClO₄/propylene carbonate (PC)] and 10% fumed silica. These systems also showed good compatibility with Li electrodes and sufficient electrochemical stability for safe operation in Li batteries. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1319–1328, 2001     

Kinetics of phase separation of poly(styrene‐co‐methyl methacrylate) and poly(styrene‐co‐acrylonitrile) blends

The phase behavior and kinetics of phase separation for blends of the random copolymer poly(styrene‐co‐methyl methacrylate) (SMMA) and poly(styrene‐co‐acrylonitrile) (SAN) were studied by using small‐angle laser light scattering. The partially miscible SMMA/SAN blends undergo spinodal decomposition (SD) and subsequent domain coarsening when quenched inside the unstable region. For blends of SMMA and SAN, the early stages of the phase separation process could be observed, unlike a number of other blends where the earliest stages are not visible by light scattering. The process was described in terms of the Cahn–Hilliard linear theory. Subsequently, a coarsening process was detected and the time evolution of q_m at the beginning of the late stages of phase separation followed the relationship q_m∝t^?1/3, corresponding to an evaporation–condensation mechanism. Self‐similar growth of the phase‐separated structures at different timescales was observed for the late stage. Copyright © 2004 Society of Chemical Industry     

Compatibility and thermal properties of poly(acrylonitrile–butadiene–styrene) copolymer blends with poly(methyl methacrylate) and poly(styrene‐co‐acrylonitrile)

The mechanical and heat‐resistant properties of acrylonitrile–butadiene–styrene (ABS) binary and ternary blends were investigated. The relationship of compatibility and properties was discussed. The results show that poly(methyl methacrylate) (PMMA) and styrene–maleic anhydride (SMA) can improve the thermal properties of conventional ABS. The Izod impact property of ABS/PMMA blends increases significantly with the addition of PMMA, whereas that of ABS/SMA blends decreases significantly with the addition of SMA. Blends mixed with high‐viscosity PMMA are characterized by higher heat‐distortion temperature (HDT), and their heat resistance is similar to that of blends mixed with SMA. For high‐viscosity PMMA, from 10 to 20%, it is clear that blends appear at the brittle–ductile transition, which is related to the compatibility of the two phases. TEM micrographs show low‐content and high‐viscosity PMMA in large, abnormally shaped forms in the matrix. Compatibility between PMMA and ABS is dependent on both the amount and the viscosity of PMMA. When the amount of high‐viscosity PMMA varied from 10 to 20 wt %, the morphology of the ABS binary blends varied from poor to satisfactory compatibility. As the viscosity of PMMA decreases, the critical amount of PMMA needed for the compatibility of the two phases also decreases. SMA, as a compatibilizer, improved the interfacial adhesiveness of ABS and PMMA, which results in PMMA having good dispersion in the matrix. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2652–2660, 2002     

Kinetic analysis of the imidization of poly(styrene‐co‐maleic anhydride) with aniline in the melt

On the basis of the competitive reactions of intermediate poly(styrene‐co‐N‐phenyl maleamic acid) (SNPMA) to produce either poly(styrene‐co‐maleic anhydride) (SMA) or poly(styrene‐co‐N‐phenyl maleimide) (SNPMI), the imidization kinetics of SMA with aniline in the molten state were investigated by a novel approach. The volatiles emitted during the reaction of SNPMA were monitored online with both thermogravimetric analysis and Fourier transform infrared (FTIR) integrated technology. The experimental results directly and definitely indicate that the amidization reaction from SMA to SNPMA in the melt was reversible. Moreover, the kinetic parameters of the competitive reactions of SNPMA in the melt to produce either SMA or SNPMI were determined by FTIR analysis and then compared with those parameters in solution that were obtained in our previous study. It was also implied that the forward ring‐opening reaction of SMA in the melt was nearly instantaneous and that the rates of the competitive reactions of SNPMA to produce either SMA or SNPMI were crucial for the total imidization of SMA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of blend composition and organoclay loading on the nanocomposite structure and properties of miscible poly(methyl methacrylate)/poly(styrene‐co‐acrylonitrile) blends

Organically‐modified montmorillonite clay nanocomposites of poly(styrene‐co‐acrylonitrile) (SAN), poly(methyl methacrylate) (PMMA) and SAN/PMMA miscible blend are investigated. Structure characteristics at the nanoscale and microscale and thermal and tensile properties are studied as a function of polymer blend composition and filler loading fraction. Blend miscibility and T_g are unaffected by up to 10% by wt. organoclay. Thermal degradation stability increases with SAN content and exhibits an optimum value of clay loading. Stiffness shows significant improvement. Tensile strength and elongation‐at‐break suffer as a result of nanocomposite formation. Modulus shows a maximum enhancement of 57% (5 ± 0.06 GPa at 10 wt% filler, 20/80 SAN/PMMA) and varies linearly with clay fraction for all compositions of matrix phase. Predictions of Halpin–Tsai composite model are in excellent agreement with the experimental behavior over full range of polymer blend composition. Fundamental aspects of a polymer blend–clay nanocomposite are clarified, such as lack of additional synergy between clay platelets and matrix, and tensile ductility reduction, compared with polymer–clay system. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Effect of in situ polymerization conditions of methyl methacrylate on the structural and morphological properties of poly(methyl methacrylate)/poly(acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene) PMMA/AES Blends

In this study, the structural and morphological properties of poly(methyl methacrylate)/poly(acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene‐g‐styrene) (PMMA‐AES) blends were investigated with emphasis on the influence of the in situ polymerization conditions of methyl methacrylate. PMMA‐AES blends were obtained by in situ polymerization, varying the solvent (chloroform or toluene) and polymerization conditions: method A—no stirring and air atmosphere; method B—stirring and N₂ atmosphere. The blends were characterized by infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and dynamic mechanical analysis (DMA). The results showed that the PMMA‐AES blends are immiscible and present complex morphologies. This morphology shows an elastomeric dispersed phase in a glassy matrix, with inclusion of the matrix in the elastomer domains, suggesting core shell or salami morphology. The occlusion of the glassy phase within the elastomeric domains can be due to the formation of graft copolymer and/or phase inversion during polymerization. However, this morphology is affected by the polymerization conditions (stirring and air or N₂ atmosphere) and by the solvent used. The selective extraction of the blends' components and infrared spectroscopy showed that crosslinked and/or grafting reactions occur on the elastomer chains during MMA polymerization. The glass transition of the elastomer phase is influenced by morphology, crosslinking, and grafting degree and, therefore, T_g depends on the polymerization conditions. On the other hand, the behavior of T_g of the glassy phase with blend composition suggests miscibility or partial miscibility for the SAN phase of AES and PMMA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Variations of the glass‐transition temperature in the imidization of poly(styrene‐co‐maleic anhydride)

The imidization of poly(styrene‐co‐maleic anhydride) (SMA) was conducted, and the glass‐transition temperatures (T_g's) of the resulting products were measured with differential scanning calorimetry. The contributions from functional groups of maleic anhydride, N‐phenylmaleamic acid, and N‐phenylmaleimide to T_g were examined. T_g increased in the order of SMA < styrene–N‐phenyl maleimide copolymer < styrene–N‐phenyl maleamic acid copolymer and followed the Fox equation. T_g of the imidized products of SMA could be controlled by the conversions of both ring‐opening and ring‐closing reactions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2418–2422, 2007     

Kinetics and simulation of the imidization of poly(styrene‐co‐maleic anhydride) with amines

The imidization of poly(styrene‐co‐maleic anhydride) with amines may improve some of its end‐use properties. The objective of this study was to examine the mechanism and kinetics with aniline (ANL) as an amine of the preparation of poly(styrene‐co‐N‐phenyl maleimide). The reaction was carried out in a tetrahydrofuran solution at 25–55°C and in an ethylbenzene solution at 85–120°C. The extent of the reaction was determined by conductance titration, a new and simple method. Two consecutive reactions were involved in the imidization: ring opening to produce an acido‐amide group and ring closing to form a corresponding imide group. The imidization rate was greatly influenced by the reaction temperature and the molar ratio of ANL to the anhydride. A model for the imidization kinetics over a wide range of reaction temperatures and concentration ranges was developed and validated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2744–2749, 2006     

Decreasing miscibility with greater heterogeneity in ternary polymer blend: poly(cyclohexyl methacrylate), poly(α‐methyl styrene) and poly(4‐methyl styrene)

A ternary blend system comprising poly(cyclohexyl methacrylate) (PCHMA), poly(α‐methyl styrene) (PαMS) and poly(4‐methyl styrene) (P4MS) was investigated by thermal analysis, optical and scanning electron microscopy. Ternary phase behaviour was compared with the behaviour for the three constituent binary pairs. This study showed that the ternary blends of PCHMA/PαMS/P4MS in most compositions were miscible, with an apparent glass transition temperature (T_g) and distinct cloud‐point transitions, which were located at lower temperatures than their binary counterparts. However, in a closed‐loop range of compositions roughly near the centre of the triangular phase diagram, some ternary blends displayed phase separation with heterogeneity domains of about 1 µm. Therefore, it is properly concluded that ternary PCHMA/PαMS/P4M is partially miscible with a small closed‐loop immisciblity range, even though all the constituent binary pairs are fully miscible. Thermodynamic backgrounds leading to decreased miscibility and greater heterogeneity in a ternary polymer system in comparison with the binary counterparts are discussed. © 2003 Society of Chemical Industry     

Miscibility windows in ternary polymer blends of a polyester,polymethacrylate and poly(styrene‐co‐acrylonitrile)

Miscibility, phase diagrams and morphology of poly(ε‐caprolactone) (PCL)/poly(benzyl methacrylate) (PBzMA)/poly(styrene‐co‐acrylonitrile) (SAN) ternary blends were investigated by differential scanning calorimetry (DSC), optical microscopy (OM), and scanning electron microscopy (SEM). The miscibility window of PCL/PBzMA/SAN ternary blends is influenced by the acrylonitrile (AN) content in the SAN copolymers. At ambient temperature, the ternary polymer blend is completely miscible within a closed‐loop miscibility window. DSC showed only one glass transition temperature (T_g) for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends; furthermore, OM and SEM results showed that PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 were homogeneous for any composition of the ternary phase diagram. Hence, it demonstrated that miscibility exists for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends, but that the ternary system becomes phase‐separated outside these AN contents. Copyright © 2003 Society of Chemical Industry     

Immiscibility–miscibility phase transitions in blends of poly(L‐lactide) with poly(methyl methacrylate)

BACKGROUND: The nature of phase transitions and apparently irreversible phase homogenization upon heating in blends of biodegradable poly(L ‐lactide) (PLLA) with poly(methyl methacrylate) (PMMA) were proven using differential scanning calorimetry, polarized optical microscopy, scanning electron microscopy and ¹H NMR spectroscopy. The complex phase behaviour in this blend system is puzzling and is a matter of debate; this study attempts to clarify the true nature of the phase behaviour. RESULTS: A PMMA/PLLA blend is immiscible at ambient temperature but can become miscible upon heating to higher temperatures with an upper critical solution temperature (UCST) at 230 °C. The blends, upon rapid quenching from the UCST, can be frozen into a quasi‐miscible state. In this state, the interaction strength was determined to be χ₁₂ = ? 0.15 to ? 0.19, indicating relatively weak interactions between the PLLA ester and PMMA acrylic carbonyl groups. CONCLUSION: The absence of chemical exchange reactions above the UCST and phase reversibility back to the original phase separation morphology, assisted by solvent re‐dissolution, in the heat‐homogenized PLLA/PMMA blend was shown. Verification of UCST behaviour, phase diagrams and solvent‐assisted phase reversibility were experimentally demonstrated in PMMA/PLLA blends. Copyright © 2008 Society of Chemical Industry