Poly(vinyl methyl ether) poly(methyl methacrylate) blends using diblock copolymer of styrene and methyl methacrylate as compatibilizer

Blends of poly(vinyl methyl ether) (PVME) and poly(methyl methacrylate) (PMMA) compatibilized by poly(styrene-block-methyl methacrylate) (P(S-b-MMA)) ale studied by FT-IR, DSC, excimer fluorescence spectrometry, and scanning electron microscopy (SEM). In FT-IR measurement the ratio of absorption intensity at 1107 cm(-1) to that at 1085 cm(-1) (I-1107/I-1085) reaches a minimum at about 10wt% block copolymer content. DSC results show that the glass transition temperature of PVME in the blends has a maximum at 10 wt% copolymer content. In plots of the ratio of excimer-to-monomer fluorescence emission intensities (I-E/I-M) VS block copolymer content, I-E/I-M increases rapidly above 10%. Ail these phenomena show that PS block chains penetrate into PVME: domains on addition of block copolymer. Above 10% copolymer content, block copolymer chains tend to form micelles in bulk phase.

In situ epoxidation of ethylene propylene diene rubber by performic acid

In this paper, epoxidation of ethylene propylene diene rubber by in situ generated performic acid is discussed. The samples have been characterized by infra-red and H-1-nuclear magnetic resonance analyses. Quantitative analysis of the reaction products is made possible by using the methyl deformation band at 1377 cm(-1) as internal standard. The conversion of double bonds increases rapidly within the first 1 h, then gradually, over 2 h, has only a slight increase. The maximum conversion ratio of double bonds is about 70%. The relative content of epoxy groups has a top value at about 7 h. The side reactions are also discussed. (C) 1997 Elsevier Science Ltd.

Synthesis, characterization and ionic conductivity of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Three comb polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type -O(CH2CH2O)(n)CH3 were synthesized and characterized, and the ionic conductivity of CP/salt complexes is reported. The conductivity of these complexes was about 10(-5)-10(-6) S cm(-1) at room temperature. The conductivity, which displayed non-Arrhenius behaviour, was analysed using the Vogel-Tammann-Fulcher equation. The conductivity maxima appear at lower salt concentration, when CP has longer side chains. Infrared (i.r.) was used to study the cation-polymer interaction. I.r. results also indicate that the ester in CP might decompose at 140 degrees C and reproduce the maleic anhydride ring. (C) 1997 Elsevier Science Ltd.

Critical surface tension of acrylamide-grafted polypropylene copolymer by the contact angle method

The contact angles theta of polar liquids on PP-g-AM copolymer (AM content 0.19, 0.26, and 0.37 wt%) were measured. The critical surface tension gamma(c) of PP-g-AM films were evaluated by the Zisman plot (cos theta versus gamma(L)), the Young-Dupre-Good-Girifalco plot (1 + cos theta) versus 1/gamma(L)(0.5), and the log(1 + cos theta) versus log gamma(L) plot. The gamma(L) values estimated by the plot log(1 + cos theta) versus log gamma(L) were smaller than those obtained by the other plots.

The miscibility of homopolymer random copolymer blends .3. Blends of SAA with polymethacrylates and polyesters

The miscibility of blends of poly(styrene-co-allyl alcohol) (SAA) with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(n-butyl methacrylate) (PnBMA), poly-epsilon-caprolactone (PCL) or polycarbonate (PC) has been studied by means of NMR, FT-IR and DSC techniques. It was found that SAA and PMMA, PEMA or PCL form miscible blends and SAA is only partially miscible with PC or PnBMA. Both phenyl groups and hydroxyl groups in SAA are involved in the intermolecular interactions between SAA and PMMA, PEMA or PCL. Also the hydroxyl-carbonyl hydrogen bonds existing in all the miscible blends studied are formed partially at the expense of the disruption of self-association of hydroxyl groups in pure SAA. (C) 1997 Elsevier Science Ltd. All rights reserved.

Ion-conducting polymers based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CPs) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo(oxyethylene) side chains of the type -O(CH2CH2O)(n)CH3 were synthesized and characterized, and complexed with lithium salts to form amorphous polymer electrolytes. Maximum conductivity close to 1.38 x 10(-4) S/cm was achieved at room temperature and at a [Li]/[EO] ratio (EO = ethylene oxide) of about 0.066. The temperature dependence of ionic conductivity suggested that the ion transport was controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulcher plots. The ionic conductivity maximum moved to a higher salt concentration as the temperature increased, indicating that a larger number of charge carriers can be transferred through polymer chains, of which free volume is increased at higher temperature. IR results indicated that the ester in CPs might decompose at 140 degrees C and reproduce the maleic anhydride ring.

Ionic conductivity of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type -O(CH2CH2O)(n)CH3 have been synthesized and characterized, and complexed with lithium salts to form amorphous polymer electrolytes. CP/salt complexes showed conductivity up to 10(-5)Scm(-1) at room temperature. The temperature dependence of ionic conductivity suggests that the ion transport is controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulcher plots. The ionic conductivity maximum moves to a higher salt concentration as the temperature increases. IR results indicate that the ester in CP might decompose at 140 degrees C and reproduce the maleic anhydride ring.

Crystallization behavior of poly(propylene)/polyamide 1010 blends using poly(propylene)-graft glycidyl methacrylate as compatibilizer

Polyamide 1010/poly(propylene) (PA1010/PP) blends were investigated with and without the addition of poly(propylene)-graft-glycidyl methacrylate (PP-g-GMA). The effect of the compatibilizer on the thermal properties and crystallization behavior was determined by differential scanning calorimetry and wide-angle X-ray diffraction. From the results it is found that the crystallization of PA 1010 is significantly affected by the presence of PP-g-GMA. PP/PA 1010 (75/25) blends containing higher amounts of PP-g-GMA show concurrent crystallization at the crystallization temperature of PP. Isothermal crystallization kinetics also were performed in order to investigate the influence of the compatibilized process on the nucleation and growth mechanism. In the PP/PA 1010 (25/75) blends, concurrent crystallization behavior was not observed, even though the amount of PPg-GMA was high.

Crystallization and intriguing morphologies of compatible mixtures of tetrahydrofuran-methyl methacrylate diblock copolymer with poly(tetrahydrofuran)

The crystallization and unusual crystalline morphologies of compatible mixtures of tetrahydrofuran-methyl methacrylate diblock copolymer with tetrahydrofuran homopolymer were studied. It is shown that the PTHF [poly(tetrahydrofuran)] block of the copolymer cocrystalizes with the PTHF homopolymer in the PTHF microphase of the blend. However, the degree of crystallinity of the PTHF block is always lower than that of the PTHF homopolymer in the PTHF microphase. The crystallizability of the PTHF microphase increases appreciably with increasing PTHF microphase size and PTHF homopolymer weight fraction in the microphase. The morphology study of the blends shows that the crystalline morphology is strongly dependent on blend composition, copolymer composition and PTHF block length, as well as crystallization temperature. When alternating PTHF and PMMA [poly(methyl methacrylate)] lamellae are formed, the macroscopic crystalline morphology could be only observed when the thickness of the PTHF lamellae is large enough (similar to 20 nm). In the blend where PMMA spherical or cylindrical microphases are formed, the crystalline morphology changes dramatically with the change in the PTHF microdomain size and PMMA interdomain distance. Many unusual crystalline morphologies have been observed. A study of the solution-crystallized morphology of the blends at different temperatures shows that the morphology is also strongly dependent on the isothermal crystallization temperature, suggesting that the PMMA microdomains may have different effects on the morphology formation when the blend is crystallized at different rates.

Poly(epsilon-capralactone)/poly(ethylene oxide) diblock copolymer .2. Nonisothermal crystallization and melting behavior

The nonisothermal crystallization behavior and melting process of the poly(epsilon-caprolactone) (PCL)/poly(ethylene oxide) (PEG) diblock copolymer in which the weight fraction of the PCL block is 0.80 has been studied by using differential scanning calorimetry (DSC). Only the PCL block is crystallizable, the PEO block with 0.20 weight fraction cannot crystallize. The kinetics of the PCL/PEO diblock copolymer under nonisothermal crystallization conditions has been analyzed by Ozawa's equation. The experimental data shows no agreement with Ozawa's theoretical predictions in the whole crystallization process, especially in the later stage. A parameter, kinetic crystallinity, is used to characterize the crystallizability of the PCL/PEO diblock copolymer. The amorphous and microphase separating PEO block has a great influence on the crystallization of the PCL block. It bonds chemically with the PCL block, reduces crystallization entropy, and provides nucleating sites for the PCL block crystallization. The existence of the PEO block leads to the occurrence of the two melting peaks of the PCL/PEO diblock copolymer during melting process after nonisothermal crystallization. The comparison of nonisothermal crystallization of the PCL/PEO diblock copolymer, PCL/PEO blend, and PCL and PEO homopolymers has been made. It showed a lower crystallinity of the PCL/PEO diblock copolymer than that of others and a faster crystallization rate of the PCL/PEO diblock copolymer than that of the PCL homopolymer, but a slower crystallization rate than that of the PCL/PEO blend. (C) 1997 John Wiley & Sons, Inc.

Isothermal crystallization of PP-g-GMA copolymer

The overall isothermal crystallization kinetics for neat polypropylene and grafted polypropylene systems were investigated. The rate constants were corrected assuming the heterogeneous nucleation and three dimensional growth of polypropylene spherulites. A semiempirical equation for the radial growth rate of polypropylene spherulites was developed as a function of temperature, and was used to determine the number of effective nuclei of different temperatures. The number of nuclei in grafted samples was estimated to be 10(2)-10(3) times larger than that of neat polypropylene. (C) 1997 John Wiley & Sons, Inc.

Synthesis and ionic conductivity studies of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type-O(CH2CH2O)(n)CH3 have been synthesized and characterized, and complexed with LiNO3 to form an amorphous polymer electrolyte. CP/salt complexes showed conductivity up to 10(-5) S/cm at room temperature. The temperature dependence of ionic conductivity suggests that the ion transport is controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulcher plots. The ionic conductivity maximum moves to a higher salt concentration as the temperature increases. IR results also indicate that the ester in CP might decompose at 140 degrees C and reproduce the maleic anhydride ring.

Rheological studies on the phase dissolution in a block copolymer

The microphase transition in a styrene-butadiene-styrene triblock copolymer was studied by rheometric mechanical spectroscopy. A high-temperature-melt rheological transition from the highly elastic, nonlinear viscous behavior typical of a multiphase structure to linear viscous behavior with insignificant elasticity typical of a single-phase structure was observed. The transition temperature is determined according to the discontinuity of the rheological properties across the transition region, which agrees well with the results obtained from the small angle X-ray scattering data and the expectation of the random phase approximation theory. Maybe for the first time, microphase dissolution was investigated theologically. The storage modulus (G') and the loss modulus (G '') increase with time during the process. An entanglement fluctuation model based on the segmental density fluctuations is presented to explain the rheological behavior in this dissolution process. (C) 1997 John Wiley & Sons.

Toughened poly(butylene terephthalate) by epoxided ethylene-propylene-diene-rubber

Blends of poly (butylene terephthalate) (PBT) and epoxided ethylene-propylene-diene terpolymer (EEPDM) were prepared. Their mechanical properties and morphology were studied by Izod impact test machine and scanning electronic microscope respectively, It was found that the notched Izod impact strength of blend PBT/EEPDM was as about 23 times as that of pure PET and about 10 times as that of blend PBT/EPDM at room temperature, The dispersed rubber particles were much smaller and the phase boundary was more blurred in blend PBT/EEPDM than in blend PBT/EPDM. The toughness of blend PBT/EEPDM was much more better than that of blend PET and PBT/EPDM, which was in good agreement with the difference between their morphologies.

Lithium ion conducting polymer electrolytes based on alternating maleic anhydride copolymer with oligo-oxyethylene side chains

A comb polymer with oligo-oxyethylene side chains of the type -(CH2CB2O)(12)CH3 was prepared from methyl vinyl ether/maleic anhydride copolymer and poly (ethylene glycol) methyl ether. The polymer can dissolve LiClO4 salt to form homogeneous amorphous polymer electrolyte. The ac ion conduction was measured using the complex impedance method, and conductivities were investigated as functions of temperatures and salt concentration. The complexes were first found to have two classes of glass transition which increase with increasing salt content, The optimum conductivity attained at 25 degrees C is in the order of 5.50 x 10(-6)Scm(-1). IR spectroscopy was used to study the cation-polymer interaction.