Miscible binary blends containing the polyhydroxy ether of bisphenol-a and various aliphatic polyesters

Blends of the polyhydroxy ether of bisphenol-A, Phenoxy, with the polyesters poly(1,4-butylene adipate), poly(ethylene adipate), poly(2,2-dimethyl-1,3-propylene succinate), poly(2,2-dimethyl-1, 3-propylene adipate), poly(1,4-cyclohexane-dimethanol succinate), and poly(?-caprolactone), are found to exhibit the single, composition-dependent glass transition temperatures characteristic of miscible systems. Phenoxy blends containing poly(ethylene succinate), poly(hexamethylene succinate), or poly(pivaloactone) were found to be immiscible. Blend interaction parameters, obtained from analysis of the melting-point depressions observed for miscible blends containing crystallizable polyester components, are found to vary with polyester chemical structure so as to suggest an optimum density of ester groups in the polyester chain for achieving maximum interaction with Phenoxy. Too many or too few ester groups lead to immiscible polyester–Phenoxy blends.     

Miscibility in PVC-polyester blends

Blends of poly(vinyl chloride), PVC, with the polyesters poly(butylene adipate), poly(hexamethylene sebacate), poly(2,2-dimethyl,1,3-propylene succinate) and poly(1,4-cyclohexanedimethanol succinate) were found to exhibit a single, composition dependent glass transition. Thus, these polyesters are miscible with PVC as others have reported for poly(?-caprolactone). However, mixtures of poly(ethylene succinate), poly(ethylene adipate) and poly(ethylene orthophthalate) with PVC were found not to be miscible. Melting point depression has been used to estimate the blend interaction parameter. These results combined with others from the literature suggest that there is an optimum density of ester groups in the polymer chain for achieving maximum interaction with PVC. Too few or too many ester groups result in immiscibility with PVC.     

Mechanochemical synthesis and characterization of poly(vinyl chloride)-block-poly(ethylene-co-propylene) copolymers by ultrasonic irradiation

Mechanical degradation and mechanochemical reaction in heterogeneous and homogeneous systems of poly(vinyl chloride) and poly(ethylene-co-propylene) polymer have been studied by ultrasonic irradiation at 30 °C. The rates of decrease in the number-average molecular weights of the degraded poly(vinyl chloride) and poly(ethylene-co-propylene) polymer were much faster in order of the solid poly(vinyl chloride)—poly(ethylene-co-propylene) polymer solution, the swelled poly(vinyl chloride)—poly(ethylene-co-propylene) polymer solution, and the homogeneous solution systems. On the other hand, mechanochemical reaction occurred by free radicals produced from the chain scissions of both polymers by ultrasonic waves. The changes in the composition of the total block copolymer, the unreacted poly(vinyl chloride), and the unreacted poly(ethylene-co-propylene) polymer in individual reaction systems were obtained. In addition, the microscopic observation of the surfaces of the polymers on before and after mechanochemical reaction is carried out. Received: 10 May 2000/Revised version: 1 August 2000/Accepted: 3 August 2000     

Polyester–polycarbonate blends. VI. Branched aliphatic polyesters

Polycarbonate blends with poly(pivalolactone) were found to be completely immiscible based on the glass transitional behavior observed by thermal analysis. Crystallinity of the poly(pivalolactone) was unaffected by blending with polycarbonate. The heat of mixing of low molecular weight analogs of this system, ethyl pivalate and diphenyl carbonate, were found to be endothermic, in contrast to exothermic mixing observed for similar linear esters. Methyl branching adjacent to the ester carbonyl is believed to shield the specific interaction of this unit with the aromatic carbonate structure which leads to exothermic mixing and miscibility of similar unbranched esters with polycarbonate. Blends of poly(2,2-dimethyl-1,3-propylene succinate) were found to be partially miscible with polycarbonate because the shielding is not so great since the methyl groups are further removed from the ester group.     

Thermally induced phase separation in homogeneous blends of poly(2,6-dimethyl-1,4-phenylene oxide) with poly(o-fluorostyrene-co-p-chlorostyrene) and with poly(o-fluorostyrene-co-o-chlorostyrene)

The phase separation behavior of initially compatible blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with poly(o-fluorostyrene-co-p-chlorostyrene) [poly(oFS-co-pCIS)] and with poly(o-fluorostyrene-co-o-chlorostyrene) [poly(oFS-co-oCIS)] was studied by DSC. It was found that copolymers of poly(oFS-co-pCIS) containing between 15 and 62 mol % pCIS have shown no phase separation after annealing at temperatures up to 320°C. It was also observed that blends containing this copolymer with 74 mol % pCIS show phase separation at 250°C, which depended on blend composition. Additionally, all PPO/poly(oFS-co-oCIS) blends exhibit phase separation after annealing to a temperature of 230°C. Thermal degradation of the polymer blends was not observed at the temperatures studied.     

Phase behavior of blends of aliphatic polyesters with a vinylidene chloride/vinyl chloride copolymer

A series of aliphatic polyesters having CH₂/COO ratios from 2 to 14 in their repeat units were blended with a copolymer of vinylidene chloride containing 13.5% by weight of vinyl chloride. Blends of polyesters having CH₂/COO < 4 did not form completely miscible amorphous phases, whereas polyesters having CH₂/COO ≥ 4 did form completely homogeneous amorphous phases for all temperatures below the decomposition point except for the polyester with CH₂/COO = 14 which showed reversible phase separation on heating, i.e., lower critical solution temperature behavior. Interaction parameters were estimated by melting point depression and by analog calorimetry. The behavior reported here is qualitatively similar to that reported earlier for blends of aliphatic polyesters with poly(vinyl chloride), polyepichlorohydrin, polycarbonate, styrene–allyl alcohol copolymers, and the hydroxy ether of bisphenol A.     

Preparation and Characterization of Poly(2,2-dimethyl-1,3-propylene oxalate) Polymer and the Study of its Metal Uptake Behavior Toward Pb(II), Cd(II), and Hg(II) Ions

Abstract

Poly(2,2-dimethyl-1,3-propylene oxalate) was synthesized from oxalyl chloride and 2,2-dimethyl-1,3-propane diol. The polymer was characterized by inherent viscosity, FT-IR, XRD, SEM, ¹H-NMR, ¹³C-NMR, DSC, and TGA. The polymer uptake behavior towards Pb(II), Cd(II), and Hg(II) ions was studied by the batch equilibrium technique as a function of pH and contact time. The adsorption isotherms of metal ions were also investigated. Column experiments were used to determine the loading capacity and study desorption of metal ions. The polymer showed high metal-ion uptake capacity towards Pb(II), but moderate capacity towards Cd(II) and Hg(II) ions. Interestingly, the polymer was found to be highly selective for Pb(II) ions at pH 5 and 25°C. The metal ion uptake properties of the polymer show fittings for both Langmuir's and Freundlich equations. The metal-bound polymer was regenerated by treatment with 1 M HNO₃. Therefore, it may be employed for the removal of heavy metal pollutants in environmental and industrial applications.     

Development of antifouling poly(vinyl chloride) blend membranes by atom transfer radical polymerization

In this study, antifouling poly(vinyl chloride) (PVC) blend membranes were prepared by blending the PVC based amphiphilic copolymer PVC‐g‐poly(hydroxyethyl methacrylate) (PVC‐g‐PHEMA), synthesized by atom transfer radical polymerization (ATRP), into the hydrophobic PVC matrix via the nonsolvent‐induced phase separation method. The in situ ATRP reaction solutions were also used as the blend additives to improve membrane performance. Attenuated total reflectance–Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy indicated that the blend membranes based on the two blend routes exhibited similar surface chemical compositions. The membrane morphology and surface wettability were determined by scanning electronic microscopy and water contact angle measurement, respectively. The blend membranes showed improved water permeability, comparable rejections and enhanced antifouling properties compared with the pure PVC membrane. The PVC blend membranes also had excellent long‐term stability in terms of chemical compositions and fouling resistance. The results demonstrated that ATRP was a promising technique to synthesize amphiphilic copolymer and prepare stable blend antifouling membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45832.     

Improvement of the dispersion degree in incompatible polystyrene/poly(n-butylmethacrylate) blends by the graft poly(2,6-dimethyl-1,4-phenylene oxide) on poly(n-butylmethacrylate)

Summary Using optical and electron microscopy it is evidenced that the introduction of graft copolymer poly(2,6-dimethyl-1,4-phenylene oxide) on poly (n-butylmethacrylate) improves substantially the degree of dispersion in the incompatible polymer blend polystyrene/poly (n-butylmethacrylate). The action of the copolymer is attributed-besides the mutual dissolution of the PBMA sequences — to the compatiblity between the PPO-grafts and the PS component of the blend. This is supported by the Tg data which show that the Tg of the PS in the blend is influenced by the present graft copolymer. The observed decrease of the Tg is explained by the concomitant admittance in the PS phase of the PBMA backbone together with the PPO grafts.     

Partial miscibility in the system poly(para-chlorostyrene-co-ortho-chlorostyrene)/poly(2,6-dimethyl-1,4-phenylene oxide)

The compatibility of random copolymers of para-chlorostyrene and ortho-chlorostyrene (PO copolymers) with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) has been studied by differential scanning calorimetry (d.s.c.). Blends prepared by compression moulding of coprecipitated powders display either one or two glass transitions, dependent on the composition of the copolymer component of the blend. PO copolymers of para-chlorostyrene content from 23 to 64% are miscible with PPO in all proportions, using the customary criteria of a single calorimetric glass relaxation and optical clarity. Both homopolymers poly(para-chlorostyrene) (P_pClS) and poly(ortho-chlorostyrene) (P_oClS) are found to be incompatible with PPO; such blends exhibit two glass transitions at temperatures characteristic of the pure component phases. All compatible PO-PPO blends undergo phase separation upon annealing at elevated temperatures, indicating that a lower critical solution temperature (LCST) must exist. The phase separation is found to be reversible by annealing below the LCST, at temperatures which are still above the glass transitions of both blend components.     

Nonisothermal crystallization kinetics of novel biodegradable poly(butylene succinate-co-2-methyl-1,3-propylene succinate)s

Two novel poly(butylene succinate-co-2-methyl-1,3-propylene succinate)s, PBMPSu 95/5 and PBMPSu 90/10, were characterized as having 6.5 and 10.8 mol% 2-methyl-1,3-propylene succinate (MS) units, respectively, by ¹H NMR. A differential scanning calorimeter (DSC) and a polarized light microscope (PLM) employed to investigate the nonisothermal crystallization of these copolyesters and poly(butylene succinate) (PBSu). Morphology and the isothermal growth rates of spherulites under PLM experiments at three cooling rates of 1, 2.5 and 5 °C/min were monitored and obtained by curve-fitting. These continuous rate data were analyzed with the Lauritzen-Hoffman equation. A transition of regime II→III was found at 96.2, 83.5, and 77.9 °C for PBSu, PBMPSu 95/05, and PBMPSu 90/10, respectively. DSC exothermic curves at five cooling rates of 1, 2.5, 5, 10 and 20 °C/min show that almost all of the nonisothermal crystallization occurred in regime III. DSC data were analyzed using modified Avrami, Ozawa, Mo, Friedman and Vyazovkin equations. All the results of PLM and DSC measurements reveal that incorporation of minor MS units into PBSu markedly inhibits the crystallization of the resulting polymer.     

Study on morphology of compatibilized poly (vinyl chloride)/ultrafine polyamide‐6 blends by styrene–maleic anhydride

Ultrafine polyamide‐6 (UPA6) with a size of 4–8 μm was prepared via jet‐milling. Blends of poly (vinyl chloride) (PVC) and UPA6 using a reactive copolymer styrene–maleic anhydride (SMA‐18%) were prepared. The change in morphology and structure of the blends were studied using differential scanning calorimetry, scanning electron microscopy, and X‐ray diffraction. The blend behavior was also determined experimentally using dynamic mechanical analysis. Contrasted to the original PA6, the crystallinity of the UPA6 decreased, the size of its crystallites were reduced, and its melting point decreased to 175°C. In all blends, PVC formed the continuous matrix phase. SMA is miscible with PVC and tends to be dissolved in the PVC phase during the earlier stages of blending. The dissolved SMA has the opportunity to react with PA6 at the interface to form the desirable SMA‐g‐PA6 copolymer. This in situ formed SMA‐g‐PA6 graft copolymer tends to anchor along the interface to reduce the interfacial tension and results in finer phase domains. Cocrystallity existed in PVC/(UPA6/SMA) at a ratio of 82/(18/5). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 850–854, 2005     

Miscibility in poly(vinyl chloride)/chlorinated poly(vinyl chloride) blends,and blends of different chlorinated poly(vinyl chlorides)

Blends of poly(vinyl chloride) with chlorinated poly(vinyl chloride) (PVC), and blends of different chlorinated poly(vinyl chlorides) (CPVC) provide an opportunity to examine systematically the effect that small changes in chemical structure have on polymer-polymer miscibility. Phase diagrams of PVC/CPVC blends have been determined for CPVC's containing 62 to 38 percent chlorine. The characteristics of binary blends of CPVC's of different chlorine contents have also been examined using differential calorimetry (DSC) and transmission electron microscopy. Their mutual solubility has been found to be very sensitive to their differences in mole percent CCl₂ groups and degree of chlorination. In metastable binary blends of CPVC's possessing single glass transition temperatures (T_g) the rate of phase separation, as followed by DSC, was found to be relatively slow at temperatures 45 to 65° above the T_g of the blend.     

Deformation behavior of HDPE/(PEC/PS)/SEBS blends

Immiscible blends of high density polyethylene (HDPE) and an amorphous glassy phase consisting of either pure polystyrene (PS) or a miscible blend of PS and a polyether copolymer (PEC) were compatibilized with various amounts of a styrene-hydrogenated butadiene block copolymer (SEBS). PEC is structurally similar to poly(2,6-dimethyl-1,4-phenylene oxide) (PPO). Using a liquid displacement stress dilatometer, the volume change of samples during uniaxial mechanical straining was determined and related to the various modes of deformation. Blends were fabricated by both injection and compression molding. Miscible PEC and PS blends were found to undergo a craze to shear yielding transition between 40 and 60% PS, which occurred at higher PS concentrations as SEBS was added. Blends with a HDPE matrix and a dispersed glassy phase showed reduced volume dilatation on adding SEBS, indicating better interfacial adhesion between the incompatible blend components. Increases in the sample volume were substantially less in blends with a PEC/PS glassy phase instead of pure PS, suggesting more effective compatibilization by the SEBS copolymer in blends with PEC. This trend is presumed to stem from an exothermic heat of mixing between the PS endblocks of SEBS and the PEC-rich phases in the blend. Microscopic evidence of the improved adhesion and modes of deformation agrees with the results obtained by dilatometry. The volume dilatation of compression-molded materials do not seem to be similarly affected by the composition of the glassy phase which may reflect morphological differences between injection-and compression-molded blends.     

Improving the antifouling property of poly(vinyl chloride) membranes by poly(vinyl chloride)‐g‐poly(methacrylic acid) as the additive

To improve the antifouling property of poly(vinyl chloride) (PVC) membranes, a series of poly(methacrylic acid) grafted PVC copolymers (PVC‐g‐PMAA) with different grafting degree were synthesized via one‐step atom transfer radical polymerization process utilizing the labile chlorines on PVC backbones followed by one‐step hydrolysis reaction. PVC/PVC‐g‐PMAA blend membranes with different grafting degree and copolymer content were prepared by nonsolvent induced phase separation method. The surface chemical composition, surface charge, membrane structures, wettability, permeability, separation performances and the fouling resistance of blend membranes were carefully investigated. The results indicated that the PMAA chains were segregated towards the surface and the membranes were endowed with negative charge. The hydrophilicity and permeability of the blend membranes were obviously improved. Furthermore, the antifouling ability especially at neutral or alkaline environments was also significantly increased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42745.     

Water-swelling behavior of an ethylene–vinyl alcohol copolymer in the presence of sorbed sodium chloride

The swelling behavior of water in a poly(ethylene–vinyl alcohol) copolymer (70 mol % vinyl alcohol) has been characterized at 25°C by vapor and liquid sorption experiments over a range of water activities. The activity of the vapor phase has been varied by incrementing the pressure of the water vapor in the sorption cell. Alternatively, for the liquid phase experiments, aqueous sodium chloride solutions of different concentrations have been used to vary systematically the activity of the water in the salt solution and to introduce various concentrations of salt into the copolymer films. Relaxation-controlled sorption and Fickian diffusion have been observed as limiting cases of the water sorption behavior at high and low water activities, respectively. The effects of sorbed sodium chloride on water vapor sorption kinetics and equilibria were determined independently. A second salt phase forms within the previously homogeneous and seemingly single phase polymeric system, upon contacting the salt-loaded film with a water vapor activity above a threshold value corresponding to the activity of water in the salt solution used to introduce the salt into the films. The water and salt solubilities in the ethylene–vinyl alcohol copolymer have been measured systematically to describe the complex sorption equilibria associated with this three-component, multiphase system.     

Structures and gas permeabilities of poly(vinyl chloride)/oligo(dimethylsiloxane) blend membranes

A series of polymer blend membranes with several weight ratios of poly(vinyl chloride) (PVC) and oligo(dimethylsiloxane) (ODMS) were prepared and the permeation behaviors of O₂ and N₂ were studied. These components are only partially miscible to each other, leading to a phase separation. In order to improve the compatibility of these polymer blends, the use of a graft copolymer PVC-g-ODMS was explored. The gas permeation studies, the thermal analyses, and the microscopic observations were made on PVC-g-ODMS/ODMS blend membranes, and the results indicate that these blend membranes have rather high gas permeabilities together with good mechanical properties.     

Effect of modifier characteristics on toughness of poly(vinyl chloride)

The effects of the mechanical properties of an acrylic graft copolymer and a silicone/acrylic composite rubber graft copolymer on the toughening of poly(vinyl chloride) (PVC) are examined. In the experiment for improvement of impact resistance of PVC, toughness of the blend polymer of a silicone/acrylic composite rubber graft copolymer is improved remarkably. The effect is attributed to the suppression of stress concentration below the fibril strength of the polymer alloy effectively by releasing the constraint of strain resulting from easy void formation at low stress. © 1996 John Wiley & Sons, Inc.     

Mechanical properties of poly(vinyl chloride) blends and corresponding graft copolymers

The mechanical properties of the poly (vinyl chloride) (PVC) and poly (glycidyl methacrylate) [poly (GMA)] blend system and the PVC and poly (hydroxyethyl methacrylate) [poly (HEMA)] blend system and their crosslinked films were investigated. At the same time, the mechanical properties for the corresponding graft copolymers such as PVC-g-GMA, PVC-g-HEMA, and their crosslinked films were also investigated in this study. The results showed that the tensile strengths for PVC–poly (GMA) blend systems were higher than those for PVC-g-GMA graft copolymer, and the tensile strengths for PVC-g-HEMA were higher than those for PVC-poly (HEMA) blend systems. However, the mechanical properties for the PVC–poly (GMA) blend system were not affected by the crosslinking of the blend system, but those for PVC-poly (HEMA) and their graft copolymers decreased with an increase of the equivalent ratio ([NCO]/[OH]) of the crosslinker. Finally, the surface hydrophilicity of the PVC-g-HEMA graft copolymer and PVC-poly (HEMA) blends were also assessed through measuring the contact angle. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 307–319, 1998     

Synthesis of core-shell emulsion copolymer of poly(butyl acrylate)/α-methyl styrene-co-methyl acrylate,with application as processing aid of poly(vinyl chloride)

The core-shell grafting copolymer of α-methyl styrene-methyl acrylate on poly(butyl acrylate) was synthesized. The particle morphology of latex and core-shell grafting polymerization was investigated as a function of: (a) reaction temperature; (b) initiator concentration used in the secondary polymerization; (c) monomer to polymer ratio; (d) emulsifier concentration. The compatibility of this copolymer with poly(vinyl chloride) (PVC) was determined by the method of solubility parameter and scanning electron microscopy. The rheological behavior of the blend of this copolymer with PVC was investigated. The mechanical properties of the blend were determined. The results show that this copolymer can be used as processing aid for PVC. © 1994 John Wiley & Sons, Inc.