Mesophilic and Thermophilic Anaerobic Digestion of Model Kitchen Waste with Variation of Fat Content

Anaerobic digestion of model kitchen waste (MKW) produced on basis of real kitchen waste (KW) is studied in batch tests. The impact of fat content of three MKWs (14.7 %, 23 %, and 27.2 % rapeseed oil content) on the biogas production at mesophilic and thermophilic conditions and two loadings is examined. The loading of 5 g_VSL⁻¹ leads to fast degradation under both temperature modes and the volume of biogas produced is only weakly correlated to the oil content. For the loading of 25 g_VSL⁻¹ a strong retardation of biogas production, high concentration of volatile fatty acids and no correlation of oil content is observed.     

Photosynthetic production of Dunaliella biomass from natural salt water and carbon dioxide

A Dunaliella strain has been isolated and grown in a medium containing saline lake water. Using 40% saline water and mixture of CO₂-air (4% CO₂) the algae grew with a specific growth rate of 0.073 h⁻¹. The maximum cell concentration was 5.6 × 10⁷ cells cm⁻³ which corresponded to 3.63 g dm⁻³ of dry biomass. Using 80% saline water, a glycerol concentration of 1.47 g glycerol g⁻¹ of, protein was obtained which amounted to 44.3% of Dunaliella dry weight. Fermentor CO₂ from a continuous yeast culture was also used as carbon source for photosynthetic growth. At 2.5% CO₂ in the exit gas a decrease of the specific growth rate was observed but the final concentration attained was comparable to that obtained with CO₂-air mixtures.     

Optimization of Food Waste Bioevaporation Process Using Response Surface Methodology

A proven bioevaporation process was used to treat food waste (FW) by mixing ground FW with biodried sludge (BS). Organic loading (OL), moisture content (MC), and air flow rate (Q_g) showed significant influences on FW bioevaporation performance. Single-parameter experiments for MC and Q_g were conducted and ranges were determined to be 55–67 wt% and 0.04–0.14 m³/kg TS_mixture · h, respectively. In order to optimize the FW bioevaporation process, a central composite design (CCD) and response surface method (RSM) were applied over the preselected ranges of OL (0.00–0.16 kg VS_FW/kg TS_BS), MC (50.91–71.09 wt%), and Q_g (0.01–0.17 m³/kg TS_mixture · h). The results indicated that OL of 0.06 kg VS_FW/kg TS_BS, MC of 59.2 wt%, and Q_g of 0.09 m³/kg TS_mixture · h were the optimal conditions for the FW bioevaporation process. Water evaporation of 123.1% and VS degradation of 108.4% were obtained under these estimated optimal conditions.     

Influence of the dopant on the polypyrrole moisture content: Effects on conductivity and thermal stability

Having in mind to produce electrically conductive carbon–epoxy composite materials, we have filled an insulating epoxy resin with an electronic conducting polymer, polypyrrole (PPy). To select the PPy that best suits this process, various PPys were chemically synthesized. The syntheses were performed in water via a dispersion polymerization route using, initially, either FeCl₃ (PPy–Cl⁻) or (NH₄)₂S₂O₈ (PPy–HSO₄⁻) as oxidizing agents. Then, using (NH₄)₂S₂O₈ as the oxidant, two other PPy doped with aromatic species were obtained due to the dissolution of paratoluenesulfonic acid (PPy–TS⁻) or naphtalenesulfonic acid (PPy–NS⁻) in the reaction media. The characterization of the PPy samples by conductivity measurements, together with elemental and thermal analysis, showed that PPy–TS⁻ exhibits the highest conductivity and thermal stability, with the conductivity remaining steady over 14 days. In addition, a stabilizing effect of the aromatic anions was observed. The experiments have shown that moisture in the PPy cannot be entirely removed and that, with increasing moisture content, the conductivity also increases, indicating an ionic conductivity superimposed on the electronic conductivity usually observed in PPy. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1567–1577, 1998     

The influence of ammonium and methods for removal during the anaerobic treatment of poultry manure

The addition of exogenous NH₄Cl to poultry manure and synthetic medium was used to study the effect of ammonia-nitrogen on the activity and composition of a methanogenic consortium. Results indicated that the production of biogas and methane was not affected by the variation in NH₄Cl concentration within the range 2–10 g dm⁻³ (0·5–2·6 g N-NH₄ dm⁻³). At higher values of ammonium (10–30 g dm⁻³ or 2–8 g N-NH₄ dm⁻³) a significant decline in both parameters (by 50–60% for biogas and 80–90% for methane) was observed. A significant decrease in the numbers of bacteria of all physiological groups (especially proteolytic and methanogenic) was observed when more than 30 g NH₄Cl dm⁻³ (7·8 g N-NH₄ dm⁻³) was added to the fermentation medium. The addition of 10% (w/v) of powdered phosphorite ore enhanced the production of biogas and methane at NH₄Cl concentrations up to 30 g dm⁻³, and also changed the composition of the methanogenic consortium. A partial recovery in the numbers of proteolytic and methanogenic bacteria coupled with the decrease in the density of sulphate-reducers was observed. High concentrations (more than 50 g dm⁻³) of NH₄Cl seemed to cause irreversible inhibition of methanogenesis which could not be eliminated by the addition of phosphorites. ©1997 SCI     

Gas permeation properties of new type asymmetric membranes

We have developed a new type of asymmetric membranes having a homogeneous hyperthin skin layer, which was used as a polyimide synthesized by 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2-bis(4-amino phenyl) hexafluoro-propane (BAAF). The skin layer thicknesses of the 6FDA-BAAF polyimide asymmetric membranes were 40–60 nm, and the porosity was 10^-6% when a defect size was assumed as 5 nm. The permselectivity of 6FDA-BAAF polyimide asymmetric membranes after silicone coating had α of 40 for CO₂/CH₄ and a flux of 1.0 [Nm³/m²-h-atm] (=3.7 × 10⁻⁴ [cm³(STP)/cm² s cmHg]) for CO₂, α of 4.3 for O₂/N₂ and a flux of 2.0 × 10⁻¹ [Nm³/m²/h/atm] (=7.1 × 10⁻⁵ [cm³(STP)/cm²s cmHg]) for O₂. These values were constant for large-scale manufacturing. © 1996 John Wiley & Sons, Inc.     

THE “WHY” OF AGEING CLAY1

Ageing of clay.—(1) Evolution of CO₂ was found to continue for over 34 days after pugging and, like the change of plasticity, to proceed more rapidly between 80° and 90° F than below 60°. (2) Effect of replacing water by non-aqueous liquids was to inhibit the development of plasticity altogether. (3) Effect of a dilute solution of H₂O² was to produce a pronounced increase of viscosity and also to stimulate the growth of filaments algae and the consequent evolution of both CO and CO₂. It seems probable, therefore, that the change of plasticity of clays with time is due, in some way, to the growth of such algae. (4) This algae theory would explain all the effects found. New chemical measure of the plasticity of clays.—The ratio of the amounts of Al₂O₃ and SiO₂ dissolved by caustic potash was found, for the three clays tested (Cooley Ball, Edgar Plastic Kaolin and Harris Spruce Pine), to decrease rapidly with diminishing plasticity and therefore might well be used as a quantitative measure of plasticity.     

Application of the Stover–Kincannon kinetic model to nitrogen removal by Chlorella vulgaris in a continuously operated immobilized photobioreactor system

BACKGROUND: The aim of this study was to evaluate the ammonium nitrogen removal performance of algae culture Chlorella vulgaris in a novel immobilized photobioreactor system under different operating conditions and to determine the biokinetic coefficients using the Stover–Kincannon model. RESULTS: The photobioreactor was continuously operated at different initial ammonium nitrogen concentrations (NH₄‐N₀ = 10–48 mg L⁻¹), hydraulic retention times (HRT = 1.7–5.5 days) and nitrogen/phosphorus ratios (N/P = 4/1–13/1). Effluent NH₄‐N concentrations varied between 2.1 ± 0.5 mg L⁻¹ and 26 ± 1.2 mg L⁻¹ with increasing initial NH₄‐N concentrations from 10 ± 0.6 mg L⁻¹ to 48 ± 1.8 mg L⁻¹ at θ_H = 2.7 days. The maximum removal efficiency was obtained as 79 ± 4.5% at 10 mg L⁻¹ NH₄‐N concentration. Operating the system for longer HRT improved the effluent quality, and the percentage removal increased from 35 ± 2.4% to 93 ± 0.2% for 20 mg L⁻¹ initial NH₄‐N concentration. The N/P ratio had a substantial effect on removal and the optimum ratio was determined as N/P = 8/1. Saturation value constant, and maximum substrate utilization rate constant of the Stover–Kincannon model for ammonium nitrogen removal by C. vulgaris were determined as K_B = 10.3 mg L⁻¹ d⁻¹, U_max = 13.0 mg L⁻¹ day⁻¹, respectively. CONCLUSION: Results indicated that the algae‐immobilized photobioreactor system had an effective nitrogen removal capacity when the operating conditions were optimized. The optimal conditions for the immobilized photobioreactor system used in this study can be summarized as HRT = 5.5 days, N/P = 8 and NH₄‐N₀ = 20 mg L⁻¹ initial nitrogen concentration to obtain removal efficiency greater than 90%. Copyright © 2008 Society of Chemical Industry     

Sliding Wear Properties of Self-Mated Yttria-Stabilized Tetragonal Zirconia Ceramics in Cryogenic Environment

The objective of the present work is to investigate the friction and wear of self-mated ZrO₂ ceramics in a cryogenic environment. Using a specially designed high-speed cryo-tribometer, fine-grained yttria-stabilized tetragonal ZrO₂ polycrystals (Y-TZP) were worn at varying loads (5–15 N) with sliding speed of 1.1 m/s in a cryogenic environment (liquid nitrogen, LN2). For comparison, the sliding tests were also conducted under selected operating conditions on self-mated Y-TZP under ambient conditions (room temperature (RT)), primarily to understand the difference in wear mechanisms for a given sliding condition. With these planned experiments, it was attempted to answer some important issues: (a) Can sliding in LN2 reduce the coefficient of friction (COF) of self-mated ZrO₂? (b) Does t-ZrO₂ transformation occur in a cryogenic environment and if it occurs, how does it affect the fracture behavior? (c) How does the mechanism of wear change from RT to LN2 temperature? In our experiments, high COF (0.35–0.75) and high wear rate of disks 10⁻⁴–10⁻⁶ mm³·(N·m)⁻¹ have been measured under the selected tribological testing conditions. Interestingly, X-ray diffraction analysis revealed the presence of o-ZrO₂ after sliding in a cryogenic environment, while no change in phase assemblage was recorded after sliding under identical conditions at RT. An important observation has been that severe plastic deformation (wider and deeper grooves) at RT and microcracking (“fish scale” pattern)-induced spalling of a damaged layer in an LN2 environment are the dominant wear mechanisms, respectively.     

Fenton oxidation and adsorption pretreatment for superior biogas recovery from biomethanated spent wash

Abstract

A key task in alcohol distilleries is the effective treatment of biomethanated spent wash after biogas recovery. This colored washwater exhibits low biodegradability index (BI?<?0.2), high chemical oxygen demand (30,000?<?COD?<?40,000?mg/L), and recalcitrance to aerobic treatment. In this work, pretreatment of biomethanated distillery wastewater by Fenton oxidation was proposed for improved biogas recovery. The effects of temperature, solution pH, and H₂O₂ dosage on the efficacy of the oxidation process were studied. Using ferrous sulfate catalyst (36?mg/L) for diluted wastewater (BOD₅?=?81; COD?=?400?mg/L), 54% reduction in COD was achieved within 1?h in acidic medium (pH?=?3) at ambient temperature (T?=?30?°C). Post-oxidation, the BI value improved (0.33). After subsequent adsorption over activated carbon (loading 5%) for 1?h, COD reduction (70%), and BI value (0.43) improved further. Upon anaerobic treatment with 1% acclimatized biomass, 1?Nm³ of biogas (47% CH₄) was additionally formed per m³ of treated wastewater; without pretreatment, this value was 0.9?Nm³ (just 11% CH₄). Lastly, aerobic treatment was performed and the results were encouraging: BI?=?0.51 and COD reduction?=?94%. Many oxidation products were identified and first-order kinetic plots were made to describe COD conversion kinetics. In this way, useful insight on a plausible technique for valorization of biomethanated washwater was provided.     

Optimization of Chlorella vulgaris cultivation grown in waste molasses syrup using mixture design

The aim of this study was to determine and optimize culture media for Chlorella vulgaris microalgae under mixotrophic conditions using waste molasses as a cheap carbon source containing both organic carbons and other nutrients. In the current study, at first the growth and lipid productivity of C. vulgaris were assessed in different culture media and the best media was selected for mixotrophic growth conditions. Significant medium ingredients were screened through Plackett–Burman design. Then ingredients with positive effect were considered as a mixture component and their combinations were evaluated on lipid productivity using mixture design. According to results, Zarrouk medium was considered as the base medium with the highest biomass and lipid productivity of 72 and 7.1 mg L⁻¹ d⁻¹, respectively. Based on the Plackett–Burman design, out of 11 factors, molasses, NaNO₃ and K₂HPO₄ demonstrated key roles in biomass and lipid productivity in mixotrophic conditions. Consequently, the selected three factors were investigated by mixture design. The results showed that high concentration of molasses causes decrease in biomass and lipid productivity due to high turbidity and a blend consisting of approximately 9.5 g L⁻¹ molasses, 5 g L⁻¹ NaNO₃ and 0.15 g L⁻¹ K₂HPO₄ was found as the optimum mixture with obtained lipid productivity of 115 mg L⁻¹ d⁻¹. In conclusion, waste molasses can be used as a promising feedstock for cost effective cultivation of C. vulgaris.     

Kinetic study of the transformation of sodalite to nepheline

The kinetics and mechanism of the development of nepheline (NaAlSiO₄) through thermal transformation of sodalite (Na₄Al₃Si₃O₁₂Cl) was studied by means of differential thermal analysis at different heating rates (10°C min⁻¹ to 50°C min⁻¹) to control the evolution of the crystallization fraction. The conversion of sodalite (cubic crystal) to pure nepheline (hexagonal crystal) took place in the 800°C–900°C interval. The activation energy for nepheline crystallization from sodalite was determined by isothermal and non-isothermal methods. The ratio t_0.75/t_0.25, together with the Avrami exponent (n) and the numerical factor of the dimensionality of crystal growth (m) parameters indicated that dominant crystallization mechanism in nepheline development is bulk crystallization mechanism controlled by interface reaction.     

Tribological behavior of three‐dimensional braided carbon fiber reinforced polyetheretherketone composites

Three‐dimensional (3D) braided carbon fiber reinforced polyetheretherketone (denoted as CF_3D/PEEK) composites with various fiber volume fractions were prepared via hybrid woven plus vacuum heat‐pressing technology and their tribological behaviors against steel counterpart with different normal loads at dry sliding were investigated. Contrast tribological tests with different lubricants (deionized water and sea water) and counterparts made from different materials (epoxy resin, PEEK) were also conducted. The results showed that the incorporation of 3D braided carbon fiber can greatly improve the tribological properties of PEEK over a certain range of carbon fiber volume fraction (V_f) and an optimum fiber loading of ∼54% exists. The friction coefficient of the CF_3D/PEEK composites decreased from 0.195 to 0.173, while the specific wear rate increased from 1.48 × 10⁻⁷ to 1.78 × 10⁻⁷ mm³ Nm⁻¹ with the normal load increasing from 50 to 150 N. Abrasive mechanism was dominated when the composites sliding with GCr15 steel counterpart under dry and aqueous lubrication conditions. Deionized water and sea water lubricants both significantly reduced the wear of the CF_3D/PEEK composites. When sliding with neat PEEK counterpart, the CF_3D/PEEK composites possess lower friction coefficient than those against epoxy resin and GCr15 steel counterparts. In general, CF_3D/PEEK composites possess excellent tribological properties and comprehensive mechanical performance, which makes it become a potential candidate for special heat‐resisting tribological components. POLYM. COMPOS., 36:2174–2183, 2015. © 2014 Society of Plastics Engineers     

Novel economical three-stage slug bubbling process in a large-scale flat-sheet membrane bioreactor of double deck configuration

Slug bubbling in single deck flat sheet membrane bioreactor (FSMBR) is effective in controlling membrane fouling. Here the primary focus is on the employment of the slug bubbling method, with its more economical air consumption, to a double-deck large-scale FSMBR with 100 membrane plates on each deck. The analysis of a new design concept shows that sufficient hydrodynamic effect could be induced by a novel economical three-stage slug aeration process of formation-breakup-reformation. Computational fluid dynamics simulation was applied to examine both the development of the slug bubble and especially its reformation. It was found that the combination of a gap between two decks of 400 mm with an air velocity of 16 m/s was an optimal condition to achieve good hydrodynamic conditions in both decks. The corresponding SAD_m is 0.098 Nm³m⁻² hr⁻¹, which is a reduction of 66% compared to the most advanced single deck FSMBR.     

Co-digestion of Municipal Sewage Sludges and Pre-hydrolysed Woody Agricultural Wastes

Material balance has been used to evaluate the COD behaviour and the time required for fed-batch digestion of mixtures of domestic sludges and pre-hydrolysed agricultural wastes. Pre-hydrolysis of the feed materials has been used to penetrate the strong lignocellulosic structure of these wastes as well as to increase the fraction of soluble organic substances in the mixture. The influence of the organic loading rate on the main process parameters (methane, carbon dioxide, total biogas productions and their respective conversion yields) has also been investigated. The organic load has been varied from 0·8 up to 6·1 g_COD dm⁻³ day⁻¹, corresponding to a range of volatile solids load of 0·6–4·5 g_VS dm⁻³ day⁻¹ for the material under consideration. These values are slightly higher than those usually employed in conventional digester for domestic sewage sludges. However, methane production reached a maximum rate of only 5·6 mmol dm⁻³ day⁻¹ at an organic loading rate of 4·6 g_COD dm⁻³ day⁻¹, while both CH₄ content and production of biogas rapidly fell over 2·2 g_COD dm⁻³ day⁻¹. On the whole, these results suggest that removal of lignin is necessary in order to carry out the continuous anaerobic digestion of pre-hydrolysed agricultural wastes rich in woody materials. © 1997 SCI.     

Aging effect on microstructure and property of strontium zirconate coating co-doped with double rare-earth oxides

Strontium zirconate coating co-doped with ytterbia and gadolinia (Sr(Zr_0.9Yb_0.05Gd_0.05)O_2.95, SZYG) and strontium zirconate coating (SrZrO₃, SZ) were prepared by atmospheric plasma spraying. The SZYG coating shows improved phase stability from room temperature to 1400°C, while its thermal conductivity (~0.8 W m⁻¹K⁻¹) is at least ~40% lower than that of the SZ coating. Both SZYG and SZ coatings were heat-treated at 1400°C up to 360 hours in air. The X-ray diffraction results reveal that both the as-sprayed SZYG and SZ coatings are composed of main phase SrZrO₃ and secondary phase t-ZrO₂. These two phases do not undergo phase transition upon heat treatment up to 360 hours in the SZYG coating, whereas t-ZrO₂ transforms into m-ZrO₂ almost completely after 20 hours heat treatment in the SZ coating, suggesting a strong promoting role in stabilizing t-ZrO₂ by the additions of Yb₂O₃ and Gd₂O₃ in the SZYG coating. The content of t-ZrO₂ is ~4.3 wt.% in the as-sprayed SZYG coating and increases to ~19.5 wt.% after 360 hours heat treatment, analyzed using Jade software. The thermal expansion coefficients (TECs) of the SZYG coatings have no abrupt decrease after heat treatment for more than 5 hours, whereas an abrupt decrease in the TECs of the SZ coating is observed after 100 hours heat treatment. The superior performance of the SZYG coating is attributed to the very stable secondary phase t-ZrO₂ stabilized by the co-doping of ytterbia and gadolinia.     

Syntheses of poly[N-(2,2 dimethoxyethyl)-N-methyl acrylamide] for the immobilization of oligonucleotides

Radical-initiated polymerization of N-(2,2 dimethoxyethyl)-N-methylacrylamide has been carried out either in chloroform or methanol using 2,2′-azobisisobutyronitrile as an initiator, allowing us to prepare acetal containing water-soluble polymers. A kinetic study in both solvents showed that this monomer fairly homopolymerized (k_p · k_t^−1/2 = 1 mol^−1/2 L^1/2 s^−1/2). Static light scattering was used to characterize the molecular weight of these polymers. In addition, the Mark–Houwink–Sakurada relationship was established based on viscosity measurements performed at 25°C in water. Recovery of the aldehyde moieties on the polymer was achieved under mild conditions using a diluted inorganic solution. The analysis of the formation of aldehyde groups was performed by ¹H- and ¹³C-NMR. The covalent binding of oligodeoxyribonucleotides was carried out in water/acetonitrile mixtures with subsequent NaBH₄ reduction of the imine bonds so as to stabilize the polymer/oligodeoxynucleotide conjugates. © 1996 John Wiley & Sons, Inc.     

Magnesium oxide synthesized with Alpinia zerumbet leaf extracts as a sustainable alternative to zinc oxide in nitrile rubber compounds: A comparative vulcanization kinetics investigation

Zinc oxide (ZnO) is the most widely used activator in the rubber industry; however, there is growing concern about its use as it can become toxic to the environment, particularly in aquatic systems. This study describes the synthesis of magnesium oxide (MgO) assisted by the Alpinia zerumbet extract, which is then used as an activator in the replacement of ZnO to vulcanize nitrile rubber (NBR) containing 33% and 45% acrylonitrile (ACN). The t₉₀ for NBR-33% and NBR-45% are 20 and 15 min, respectively. This indicates a reduction of 5 min in t₉₀ with an increase in ACN. In comparison, ZnO-activated NBR compounds exhibit the opposite trend, with t₉₀ increasing from 10 for NBR-33% to 19 min for NBR-45%. Furthermore, the decrease in activation energy (E_a) with the increase in conversion for 33%-MgO and 45%-MgO indicates that vulcanization with MgO is a complex process. This behavior is comparable to that of 45%-ZnO, but not for 33%-ZnO because its E_a remains oscillating at 80–90 kJ mol⁻¹ in the entire conversion range. The crosslink densities of 33%-MgO and 45%-MgO are 5.87 and 4.78 mol cm⁻³, respectively. These values are slightly higher than those for 33%-ZnO (5.77 mol cm⁻³) and 45%-ZnO (4.38 mol cm⁻³).     

Reactions of Photoexcited Triplet States of Zinc Porphyrin with Transient Radicals in Aqueous Solutions

The technique of simultaneous pulse radiolysis and photolysis, PRAP, has been utilized to study the reactions of various radicals with ground state ZnTPPS and the triplet state ZnTPPS^T in aqueous solutions. The radicals H and OH add to both states with k ∼ 1 × 10¹⁰ M⁻¹ s⁻¹. The CH₂C(CH₃)₂OH radical from t-BuOH is relatively inert toward ZnTPPS but reacts rapidly (k = 1.8 × 10⁹ M⁻¹ s⁻¹) with ZnTPPS^T to form an adduct. Electron transfer reactions are found to be about an order of magnitude faster with the triplet than with the ground state. The (CH₃)₂COH radical reduces both ZnTPPS (k = 1 × 10⁸ M⁻¹ s⁻¹) and ZnTPPS^T (k = 3 × 10⁹ M⁻¹ s⁻¹) to the anion radical (ZnTPPS)⁻. The radical Br⁻₂ oxidizes both states to the cation radical (ZnTPPS)⁺ with k = 8 × 10⁸ M⁻¹ s⁻¹ for the ground state and 5 × 10⁹ M⁻¹ s⁻¹ for the triplet. The transient cation Cd⁺ reduces both states with a diffusion-controlled rate (k = 1 × 10¹⁰ M⁻¹ s⁻¹) to produce the anion radical. The above mechanisms of radical addition and electron transfer are also supported by the product spectra.     

Syntheses and electric conductivities of poly(methyl vinyl ketone-co-acryl amide)s reacted with phosphorus oxychloride

Studies have been made on the conductivities of poly(methyl vinyl ketone-co-acryl amide) [poly(MVK-co-AAm)]s after having reacted with phosphorus oxychloride. It was found that the conductivities were dependent on the mol ratio of [AAm] to [MVK], copolymerization temperature, and time. The effect of treatment conditions of POCl₃ on the conductivities of the poly(MVK-co-AAm)s was shown to be significant. It was observed that the conductivities of the poly(MVK-co-AAm)s, treated with POCl₃, are of the order of 10⁻⁶–10⁻⁹Scm⁻¹. The maximum conductivity of the POCl₃-treated poly(MVK-co-AAm) was obtained as 8.7 X 10⁻⁶ Scm⁻¹ when the mol ratio of AAm to MVK was 0.5. The conductivity of the poly(MVK-co-AAm) was increased with the treatment time and concentrations of POCl₃. © 1992 John Wiley & Sons, Inc.