The structural color in the polymer blend of poly(methyl methacrylate) and polystyrene

Morphologic and optical studies were performed on the coloring of poly(methyl methacrylate) (PMMA) and polystyrene (PS) opal sheet. It was concluded that the origin of color is the polymer structure itself. There exist three structures in the colored polymer blend: small PS spheres are dispersed in the PMMA matrix, and each PS sphere contains smaller PMMA spheres within it. The dimension of the smaller PMMA spheres is of the same order as the wavelength of visible or near-infrared light. The coloring measured by a spectrometer is well interpreted by the equation of structural color derived by Clewell qualitatively.     

Preparation of porous membranes grafted with poly(spiropyran-containing methacrylate) and photocontrol of permeability

Graft copolymerization of spiropyran-containing methacrylate (SPMMA) and acrylamide (AM) onto the surface of a porous polymer membrane was carried out. The permeability of the graft membrane varied with ultraviolet (UV) - or visible-light irradiation. It was found that the change by UV-light irradiation of the permeability of the H₂O/CH₃OH mixture through the SPMMA/AM-grafted membrane is related to the change by UV-light irradiation of the solubility, i.e., the chain extension, of the graft copolymer in the mixed solvent. When the free SPMMA/AM copolymer becomes insoluble in the H₂O/CH₃OH mixture by UV-light irradiation, the permeability of the H₂O/CH₃OH mixture through the SPMMA/AM-grafted membrane is increased. © 1994 John Wiley & Sons, Inc.     

Dynamic mechanical behavior of poly(vinyl chloride)/poly(methyl methacrylate) polymer blend

A poly(vinyl chloride) (PVC)/poly(methyl methacrylate) (PMMA) (80/20 w/w) polymer blend was studied by mechanical spectroscopy. Two relaxations can be distinguished: in the glassy state, a very large secondary relaxation in the range of 100 K to 325 K which results from the combination of secondary relaxations of PVC and PMMA; and only one main relaxation at 364 K associated to the glass rubber transition. The relaxation spectrum in the range of the β relaxation has been described by a relaxation time distribution function based upon a Gaussian function and a series-parallel model. The α relaxation was studied by means of a theoretical approach for the nonelastic deformation of polymers. We found that the miscibility of this blend appears to be a function of the observation scale: the PVC/PMMA blend is heterogeneous at the scale of molecular movements involved for the β relaxation process but homogeneous at the scale of the chain segments responsible for the α relaxation dynamics. © 1996 John Wiley & Sons, Inc.     

CO2 foaming based on polystyrene/poly(methyl methacrylate) blend and nanoclay

A poly(methyl methacrylate) (PMMA) and nanoclay composite was dispersed into polystyrene (PS) using a twin‐screw extruder. The mixture was then batch foamed with supercritical CO₂. It was found that the cell density of foams based on the blend is higher than that based on the weight average of the two pure polymer components at the same foaming conditions. The cell size decreases and the cell density increases with the increase of the PMMA domain size. One explanation is that the large PMMA domains serve as a CO₂ reservoir and the nucleation in the PS phase is enhanced by the diffusion of CO₂ from the PMMA phase to the PS phase. Very small PMMA domains cannot function as a CO₂ reservoir, and so they are not able to facilitate the nucleation. A much higher cell density and smaller cell size were observed when nanoclay was located at the interface of the PMMA and the PS domains, serving as the heterogeneous nucleating agents. POLYM. ENG. SCI., 47:103–111, 2007. © 2007 Society of Plastics Engineers     

Preparation and properties of poly(butyl methacrylate/lauryl methacrylate) and its blend fiber

The functionalized copolymers, based on butyl methacrylate (BMA), and lauryl methacrylate (LMA) with crosslinking agent HEMA (hydroxyethyl methacrylate) or DVB (divinyl benzene), have been innovatively synthesized by suspension polymerization for oil absorption. Further, the copolymers and polypropylene (PP) blend fiber were attained via melt spinning. Swelling behaviors were evaluated by equilibrium swelling experiment, oil absorbency test, gel fraction measurement, and optical observations in toluene. The thermal properties and morphologies of the blend fibers were analyzed by thermogravimetry (TGA) and a field-emission scanning electron microscope, respectively. The results show that the copolymers and their blend fibers have an impressive absorbency. PBMA/LMA/HEMA can be up to 35.18?g/g, showing the highest absorption in trichloroethylene. Optical images of swollen polymers in toluene depicted a colloidal translucence with gel structure. Thermogravimetric measurement demonstrates that the copolymer and PP are incompatible and PBMA/LMA/DVB component possesses more thermal stability. The micrographs of the blend fibers exhibit coarse surface and porous cross-section, which leads to the fibers being much more readily wetted by oil and provides a huge space for oil storage.     

Nanostructured polymer blend formed from poly(N-vinylpyrrolidone) and end-functional polystyrene

Phase structures of blends of poly(N-vinylpyrrolidone) (PVP) with SO₃H terminated polystyrene (PSS) were investigated. The PVP-PSS blends were macroscopically homogeneous, although the blends of PVP with polystyrene (PS) showed macroscopic phase separation. The PVP-PSS blends, however, showed two glass transitions indicating existence of two phases. Small-angle X-ray scattering measurements revealed the PVP-PSS blends formed mesomorphically ordered morphologies which change with variation of blend composition. The nano-organized phase separation in the PVP-PSS blends was caused due to hydrogen bonding of the PVP with the terminal SO₃H group of the PSS and repulsive interaction between PVP and main chain of the PSS.     

聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子的制备

由种子乳液聚合法制备了聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子。以过硫酸钾(KPS)为引发剂,辛基酚聚氧乙烯醚(OP-10)为乳化剂,合成了聚苯乙烯(PS)种子核;连续滴加甲基丙烯酸甲酯(MMA),在核表面富集MMA,制备了粒径范围在0.16~0.67μm的核-壳粒子;当单体苯乙烯与甲基丙烯酸甲酯(St/MMA)的比为30∶70(质量比)时,所得粒径在0.18μm,粒径分布为0.012。差示扫描量热(DSC)研究显示,复合粒子的玻璃化转变温度(Tg)为97.2℃,峰形单一,表现出良好的热性能。     

Rheological and mechanical properties of poly(lactic acid)/polystyrene polymer blend

Properties modification by blending polymers has been an area of immense interest. In this work, rheological and mechanical properties of poly(lactic acid)/polystyrene (PLA/PS) blends were investigated. PLA/PS blends in different ratios were prepared using a laboratory scale single screw extruder to obtain (3 mm) granules. Rheological properties were studied using a capillary rheometer and the Bagley’s correction was performed. True shear rate (γ _r ), true shear stress (τ _r ), and true viscosity (η _r ) were determined, the relationship between true viscosity and (1/T) was studied for PLA70 blend and the flow activation energy at a constant shear stress (E _τ ) and a constant shear rate (E _γ ) was determined. The mechanical property measurements were performed at room temperature. Stress at break and strain at break were determined. The results showed that PLA/PS blend exhibited a typical shear-thinning behavior over the range of the studied shear rates, and the viscosity of the blend decreased with increasing PLA content. Also it was found that no equal-viscosity temperature exists between PLA and PS. The mechanical results showed immiscibility between PLA and PS in the blend.     

Preparation and characterization of novel crosslinked poly[glycidyl methacrylate–poly(ethylene glycol) methyl ether methacrylate] as gel polymer electrolytes

In this study, glycidyl methacrylate was copolymerized with poly(ethylene glycol) methyl ether methacrylate to obtain a copolymer {poly[glycidyl methacrylate–poly(ethylene glycol) methyl ether methacrylate] [P(GMA–PEGMA)]}, which was crosslinked with α,ω‐diamino poly(propylene oxide) (Jeffamine) at various weight ratios and molecular weights to form novel gel polymer electrolytes (GPEs). The crosslinked copolymers were characterized by Fourier transform infrared spectroscopy and thermal analysis. The crosslinked polymers were amorphous in the pristine state and became crystallized after they were doped with lithium electrolyte. Furthermore, the crosslinking degree of the crosslinked polymers increased with increasing weight ratio of Jeffamine, and both the swelling properties and mechanical behaviors of the crosslinked polymers were heavily affected by the weight ratio and molecular weight of Jeffamine. The ionic conductivity (σ) of the GPEs from the crosslinked copolymers was determined by alternating‐current impedance spectroscopy. A higher molecular weight and increased weight ratio of Jeffamine resulted in a higher σ. The GPE based on P(GMA–PEGMA) crosslinked with an equal weight of Jeffamine D2000 exhibited the highest σ of 8.29 × 10⁻⁴ S/cm at 25°C and had a moderate mechanical strength. These crosslinked copolymers could be potential candidates for the construction of rechargeable lithium batteries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Solution blending of polystyrene and poly(methyl methacrylate)

Blends of poly(methyl methacrylate) (PMMA) and polystyrene (PS) have been investigated by differential scanning calorimetry and scanning electron microscopy. Blends were made of a low molecular weight PS with three PMMAs having number-average molecular weights of (1) 18,300, (2) 37,000, and (3) 211,000, The blend was found to be partially miscible. The composition-dependent values of the polymer-polymer interaction parameter (g₁₂) were determined and found to be from 0.015 to 0.029 for solution casting at 25°C. The interaction parameter (g₁₂) increases with increasing PMMA molecular weights in the PMMA/PS blend systems. This result is consistent with the behavior of the glass transition temperatures and with the microscopy study which indicate that compatibility is greater in the PMMA-1/PS blends having the low molecular weight of PMMA than in the PMMA-3/PS blends having the higher molecular weights of PMMA.     

聚醚砜/磺化聚醚醚酮共混膜的制备和性能

采用流延法制备了聚醚砜(PES)含量不同的PES/磺化聚醚醚酮(SPEEK)共混膜。PES与SPEEK具有良好的相容性。所制备PES/SPEEK共混膜的含水率、溶胀度和甲醇透过系数均随PES含量的增加而降低。虽然共混膜的质子传导性能有所降低.但阻醇性能和溶胀性能提高,这说明PES/SPEEK共混膜是一种很好的直接甲醇燃料电池用固体高分子电解质膜材料。     

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.     

Segmented polymer networks based on poly(N-isopropyl acrylamide) and poly(tetrahydrofuran) as polymer membranes with thermo-responsive permeability

Segmented polymer networks (SPNs) containing a polymer with a lower critical solution temperature were prepared by free radical copolymerization of poly(tetrahydrofuran) (PTHF) bis-macromonomers with N-isopropyl acrylamide (NIPAA). The PTHF bis-macromonomers, which were prepared by living cationic polymerization of tetrahydrofuran, were provided with acrylate or acrylamide end-groups by end-capping the living polymer chains with acrylic acid and 3-acrylaminopropanoic acid, respectively. Differential Scanning Calorimetry (DSC) experiments showed clearly that, for the same fractions of both network components, the phase morphology of the SPNs was highly influenced and adjustable by the nature of the end-groups of the bis-macromonomer as a result of their copolymerization behavior with NIPAA. For the same type of multi-component networks, the morphology changed from a heterogeneous up to a rather homogeneous nature by application of bis-macromonomers with, respectively, acrylate or acrylamide end-groups during their preparation. Swelling and DSC experiments on the swollen SPNs revealed, respectively, that the swelling properties and the cloud point temperature (T_cp) could be controlled by the network composition. The thermo-responsive water permeability and the possible application of the SPNs as pervaporation membranes for the separation of a water/isopropanol mixture were investigated as a function of temperature and network composition. The permeability and selectivity of the membranes decrease when the T_cp is reached. The permeability increases while the selectivity decreases with decreasing crosslink density or higher overall hydrophilicity of the SPNs.     

Preparation and characterizations of interpenetrating polymer network hydrogels of poly(ethylene oxide) and poly(methyl methacrylate)

Interpenetrating polymer network (IPN) hydrogels based on poly(ethylene oxide) and poly(methyl methacrylate) were prepared by radical polymerization using 2,2‐dimethyl‐2‐phenylacetophenone and ethylene glycol dimethacrylate as initiators and crosslinkers, respectively. The IPN hydrogels were analyzed for sorption behavior at 25°C and at a relative humidity of 95% using dynamic vapor sorption. The IPN hydrogels exhibited a relatively high equilibrium water content in the range of 13–68%. The state of water in the swollen IPN hydrogels was investigated using differential scanning calorimetry. The free water in the hydrogels increased as the hydrophilic content increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 258–262, 2003     

Sequential interpenetrating polymer network based on nitrile–phenolic blend and poly(alkyl methacrylate)

Interpenetrating polymer networks (IPNs) based on a nitrile rubber (NBR)–phenolic resin (PH) blend and poly(alkyl methacrylates) were synthesized by a sequential method. The cured blends were swollen in a methacrylate monomer containing a crosslinker and initiator. The swollen rubber sheets were cured at 60°C. From the swelling study of the monomer, it was found that IPN formation in the blend is in between the rubber and poly(alkyl methacrylate) phases only. The IPNs thus formed were characterized for their tensile, dynamic mechanical, and solvent-resistance characteristics. The tensile strength of the IPNs are dependent on the PH content; at a lower content of PH (up to 20 parts), IPNs have a higher strength compared to their corresponding blends, whereas at a higher content of PH (beyond 30 parts), the strength decreases. But for every NBR/PH-fixed composition, the strength of IPNs was found to be increasing in the order of PBuMA < PEMA < PMMA. The dynamic property results showed that NBR/PH blends are incompatible. The storage modulus of IPNs are always higher than their corresponding blends at all temperatures. The tan δ peaks of IPNs are broad, indicating the presence of microphase-separated domains. The IPNs show superior solvent-resistance characteristics compared to the blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:255–262, 1998     

Biocompatible electrospun tactic poly(methyl methacrylate) blend fibers

Uniform and beads free fibers of pristine syndiotactic PMMA (s-PMMA), isotactic PMMA (i-PMMA), and their blends in the ratio of s:i = 3:1, 1:1 and 1:3 were successfully prepared using the electrospinning technique. The tactic PMMA blend fibers showed unique thermal stability and glass transition temperatures compared to their pristine counterparts. An interesting endotherm peak was observed for the s:i = 1:3 electrospun fibers, which might indicate a complex formation between the two tactic PMMAs. Systematic surface functionalities study by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) revealed the interactions between these two tactic PMMAs. Biocompatibility of tactic PMMA and their blend fibers was first time comparably investigated using HeLa as the model mammalian cell line; an intriguing observance was first revealed that the blend fibers showed better biocompatibility than both pristine ones, though the behind mechanism is not well understood yet.     

Preparation of polystyrene/poly(methyl methacrylate) blends by compressed fluid antisolvent technique

Submicron polystyrene (PS)/poly(methyl methacrylate) (PMMA) blends were generated by the precipitation with a compressed antisolvent (PCA) technique. The generation of PS/PMMA blends was carried out by spraying a solution containing PS and PMMA into a precipitator. The blends without coalescence were observed to only be generated when both vapor and liquid CO₂ existed in the precipitator combined with appropriate total polymer concentration in solution, molecular weights (Mws) of PS and PMMA, mass ratio of PS to PMMA, flow rates of CO₂ and polymer solution, and liquid CO₂ level in the precipitator. Two Mws of PS, 144,000 and 44,000, and two Mws of PMMA, 85,000 and 36,000, were used in this study. It was found that the blends could be easier to generate using a higher PS Mw, a lower PMMA Mw, and a higher mass ratio of PS to PMMA. Toluene with a solubility parameter smaller than that of tetrahydrofuran (THF) was found to be the more appropriate solvent for generating spherical PS/PMMA submicron blends. The SEM and TEM images show that the spherical PS/PMMA core/shell blends could be generated at a temperature of 298 K, a pressure of 6.41 MPa, a liquid CO₂ level of 1/2 of the precipitator, a CO₂ flow rate of 2000 mL/min, a solution flow rate of 5 or 10 mL/min, and a total polymer concentration of 0.72 wt% for a PS Mw of 144,000, a PMMA Mw of 36,000, and a PS/PMMA mass ratio of 9/1. Individual and spherical PS and PMMA particles or spherical PS particles partially covered by a PMMA films, however, were generated when the liquid CO₂ level was of 1/8 or lower in the precipitator. A possible mechanism for the formation of core-shell blend was proposed.     

Rheological properties of polystyrene and poly(methyl methacrylate) blends

Rheological properties of the polystyrene (PS) and poly(methyl methacrylate) (PMMA) blends were studied by Advanced Rheometric Expansion System (ARES). Storage modulus and loss modulus of the PS and PMMA blends were measured, and the interfacial tension of the PS and PMMA blends were obtained with various emulsion models by using the storage modulus and loss modulus of the blends. The value of interfacial tension estimated from the Palierne emulsion model was found to be 2.0 mN/m. Also, the interfacial tension between PS and PMMA was calculated by a theoretical model. The values of interfacial tension of the PS and PMMA blends obtained by the experiment and theoretical model were found to be in good agreement.     

Preparation of plasma-polymerized membranes from I-(trimethylsilyl)-I-propyne and gas permeability through the membranes

Summary Plasma-polymerized membranes for gas separation were prepared from 1-(trimethylsilyl)-1-propyne. The permeation data of He, H₂ 0₂, N₂, CO₂, and CH₄ through the membranes showed plasma-polymerized 1-(trimethylsilyl)-1-propyne had high permselectivity but low permeability compared with poly[l-(trimethylsilyl)-1-propyne]. This behavior is considered to be due to the crosslinking structure of the plasma-polymerized membrane. The correlation between plasma polymerization conditions and the membrane performance was studied. The optimum condition at which the deposition rate of the plasma polymer is maximized agreed with the optimum value to yield maximum separation factor of gases through the membrane.