Plasma polymerization of tetrafluoroethylene. I. Inductive radio frequency discharge

The plasma polymerization of tetrafluoroethylene in an inductively coupled radio frequency glow discharge, using a flow system, was studied. A simple long tube reactor, with the coupling coil placed at the middle of the tube and gas entrance and exit at the respective ends, was used. Deposition rates and the chemical nature of the polymer (as revealed by ESCA spectra and surface energy studies) are obtained as a function of location in the reactor tube with respect to the coupling coil and of applied energy per unit mass of tetrafluoroethylene (W/FM). It was found that a fluorinepoor polymer, containing considerable carbon–oxygen bonds (after contact with air), is obtained at all locations at high W/FM. When a low W/FM is utilized, such a fluorine-poor polymer is also obtained at locations downstream from the coupling coil (the location of the highest energy density) in the reactor. In the latter case a fluorine-rich polymer containing very little oxygen is formed upstream from the coil. The polymer deposition rate distribution is also considerably broader in a high W/FM plasma than when low W/FM is used. These results are in agreement with earlier studies indicating that fluorine abstraction and decomposition due to fluorine etching occur when the energy density, as expressed by W/FM, is high.     

Thermoplastic urethane elastomers. I. Effects of soft-segment variations

A series of thermoplastic urethane elastomers with soft segments of varying sequence length was prepared and their dynamic mechanical properties were characterized over a wide temperature range. The polymers were prepared using various molecular weight polycaprolactone diols as the soft segment and 4,4′-diphenylmethane diisocyanate and 1,4-butanediol as the hard segment. The urethane elastomer exhibited soft-segment crystallization when a polycaprolactone diol greater than 3000 M?_n was used. The glass transition temperature of these materials progressively shifted to lower temperatures as the chain length of the soft segment was increased. This dependence was interpreted in terms of a molecular weight relationship similar to that associated with amorphous homopolymers. The dynamic mechanical properties of these polyurethanes appear to be consistent with responses observed for compatible copolymers.     

Synthesis and fungicidal activities of polymeric biocides. I. TBZ-containing monomer and polymers

The fungicidal monomer, N-acryloyl-2-(4′-thiazolyl) benzimidazole (AcTBZ) was synthesized from 2-(4′-thiazolyl) benzimidazole (TBZ) and acryloyl chloride in the presence of triethylamine in dry benzene at 30°C. The synthesized AcTBZ was identified by IR and ¹H-NMR spectra. The homopolymers of AcTBZ were obtained using BPO as a thermal initiator in benzene under different experimental conditions such as various initiator concentrations or polymerization temperatures. The homopolymer of AcTBZ was also prepared using benzophenone as a photo initiator in DMF at 20°C. The average molecular weights (Mw ) of those poly(AcTBZ) s obtained were very low, being in the order of ca. 10³. Copolymer of AcTBZ and polymer of AcTBZ and acrylic acid (AA) was synthesized with thermal or photo initiators. Poly(AcTBZ) and poly(AcTBZ-co-AA) were identified by IR and ¹H-NMR spectra. The fungicidal activities of AcTBZ, poly(AcTBZ), and its polymers as well as TBZ against Aspergillus niger and Chaetomium globusum were very excellent compared to those of control polymers such as poly(AA) and poly(ethylene-co-vinyl acetate). The fungicidal activities were decreased in the order TBZ > AcTBZ > poly(AcTBZ) > poly(AcTBZ-co-AA) against both Aspergillus niger and Chaetomium globusum. The fungicidal activities of TBZ, and the synthesized AcTBZ and polymers containing AcTBZ were better against Chaetomium globusum than against Aspergillus niger. © 1994 John Wiley & Sons, Inc.     

Biodegradation of nitrate esters. II. Degradation of nitrocellulose by a fungus isolated from a double-base propellant

An organism found to be growing on moist double-base propellant, containing nitrocellulose (NC) and nitroglycerine aerobically degraded NC in submerged cultivation. This organism, which was subsequently identified as Penicillium corylophilum Dierckx, was able to degrade the NC (13.17%N) when it was present as the sole nitrogen source, in conjunction with either starch or xylan as a carbon source. It was found that 20% of the NC was utilized in a 3-day period. Also, NC degradation was studied utilizing Fusarium solani IFO 31093, a denitrifying fungus, in combination with P. corylophilum; however, no increased utilization was observed. Evidence for the degradation includes a decrease in the NC weight, an increase in the biomass weight, the presence of celluloytic and denitrifying enzymes, and other appropriate growth parameters. © 1995 John Wiley & Sons, Inc.     

Proteins from Crambe abyssinica oilseed. I. Isolation procedure

Crambe abyssinica is a promising new oil crop because of the specific properties of its oil. However, little information is available concerning the properties of the proteins, which constitute a major component of the seed. Therefore, a method for the isolation of proteins from Crambe seeds was developed. Protein extractability for whole and dehulled Crambe meal was studied as a function of pH. Highest extractability was obtained with dehulled meal at pH 11. Double extraction at this pH increased the extractability to about 66%. Protein precipitation from the above-mentioned extract was studied as a function of pH with and without addition of a precipitating agent, i.e., carboxymethylcellulose (CMC). Addition of CMC resulted in a protein recovery of about 75% at pH 4.4. Without CMC, about half of the protein was recovered by isoelectric precipitation. The remaining soluble protein could be concentrated by ultrafiltration with a recovery of about 65%. The developed process, not including CMC addition, results in two protein fractions, i.e., an isoelectric precipitate (protein content 75%) and a retentate (protein content 87%), which together account for about 50% of the protein present in Crambe meal. Application of heat decreased protein extractability, but the protein contents of the resulting fractions were comparable to those from non-heat-treated meal.     

Binders for higher-solids coatings. IV. Liquid–crystalline acrylic lacquers

A previously reported synthetic procedure was used to graft oligo-p-hydroxybenzoic acid (oligo-PHBA) to COOH-functional acrylic copolymers. Most of the products were side-chain LC copolymers. Length of the mesogenic oligo-PHBA groups averaged up to five aromatic rings per group. Because these long mesogenic groups have a strong tendency to form LC domains, it was possible to prepare LC side-chain copolymers having as little as 5 mol % of mesogenic monomer. Thus this synthetic procedure provides a versatile route for exploration of the properties of LC copolymers having relatively few but especially effective mesogenic groups. The potential utility of such LC copolymers as binders for nonbake coatings was assessed. Variables studied were molecular weight and T_g of the acrylic copolymer backbone, number and average length of oligo-PHBA segments, and the presence or absence of a flexible spacer between the acrylic backbone and the PHBA segments. Optimum LC copolymers have moderate (15,000–30,000) M_n, low (?10°C) backbone T_g, and low (5–7.5 mol %) population of long (5 PHBA units) oligo-PHBA units. Such copolymers have two major advantages as coatings binders: They form concentrated, stable, low-viscosity dispersions in common solvents, a very desirable characteristic for application. Coating films have excellent adhesion to metal, and they have an extraordinary combination of hardness (H–2H) and impact resistance (> 80 in. Ib). These properties are key indicators of coating performance and indicate that LC copolymers have excellent potential for use as binders for nonbake coatings. Other properties remain to be investigated.     

Rapid,quantitative HPLC analysis ofAsclepias fruticosa L. andDanaus plexippus L. cardenolides

The cardenolide extracts from latex and aerial parts ofAsclepias fruticosa and ofDanaus plexippus reared onA. fruticosa orA. curassavica were purified by adsorption chromatography on silica gel. HPLC analysis on a C₁₈ reverse-phase column with an acetonitrile-water gradient as mobile phase, separated 28 compounds with a UV spectrum typical forcardenolides. Afroside and gomphoside (major components), as well as calotropagenin, calotoxin, calotropin, calactin, uscharidin, uscharin, and voruscharin, occurred as single peaks in the profiles of latex and aerial plant parts ofA. fruticosa. Calactin and calotropin were the major cardenolides inDanaus plexippus reared onA. fruticosa orA. curassavica. Quantitative data obtained with digitoxin as internal standard showed that 1.3–1.5% of the leaf cardenolides were sequestered byDanaus plexippus in which levels of 70–80g cardenolide per butterfly were measured. The calotropin from the leaves was almost completely sequestered, and 10–13% of the calactin was stored by the butterfly, assuming that no conversion occurred in larval tissues. Apocynales: Asclepiadaceae. Lepidoptera: Danaidae.     

Studies on the stretching of polypropylene film. II. Polyaxial stretching

Polypropylene film was stretched polyaxially at 100–160°C., and the orientation behavior was studied by means of optical and x-ray method. The molecular chains oriented progressively to the film surface with an increase in stretching area v_A in the range 1–16, and the (040) selective uniplanar orientation developed at the extreme stretching. The plot of orientation versus v_A was less steep when the stretching was carried out at higher temperature, but the final degree of orientation was independent of the temperature, because the final v_A increased with temperature. At 160°C. premelting occured to such a degree that the high stretching and, consequently, the high orientation could not be obtained. The orientation of the amorphous chains was always behind that of the crystalline region. In the initial stage the polyaxial stretching was not as effective in attaining high biaxial orientation as the two-step biaxial stretching, but the final orientation was the same in both types of stretching because v_A reached a value of 16 in the polyaxial stretching while it was only 2 in biaxial stretching.     

Floral volatiles ofTanacetum vulgare L. attractive toLobesia botrana den. et schiff. females

The European grapevine moth (EGVM),Lobesia botrana, is a major pest of grapes in Europe. Females are attracted to a nonhost plant: tansy (Tanacetum vulgare L.), which is a common weed in Slovakian vineyards. A steam distillate extract of tansy flowers was analyzed by means of a GC-EAG technique to screen constituents detected by the olfactory receptors of EGVM females. From more than 200 GC peaks, nine peaks corresponding to monoterpenoids released an EAG response in more than 70% of the females (N=15):p-cymene,d-limonene,-thujene,-thujone,-thujone, thujyl alcohol, terpinene-4-ol, (Z)-verbenol, and piperitone. The steam distillate of tansy as well as a synthetic blend of identified compounds released consistent attraction in a field cage. The use of nonhost plants and host plant odors in integrated pest management is discussed.     

A generalized model to predict the viscosity of solutions with suspended particles. III. Effects of particle interaction and particle size distribution

The generalized suspension viscosity equation utilized in this study was evaluated with both a packing fraction, φ_n, and a particle interaction coefficient, σ, as a function of suspension blend composition, f_2T. The estimation of the packing fraction, φ_n, in turn, required the further elucidation of the D₅/D₁ ratio of particle diameter averages. Blend constants developed in this study allowed evaluation of both the D_x/D_y ratio of particle diameter averages as well as the number-average particle diameter, D₁, as a function of the fraction of one suspension in a blend, f_2T. These blend constants were shown to be easily evaluated from each individual suspension prior to blending. The viscosity data of Johnson and Kelsey were shown to be generally predicted as a function of the volume composition when a constant particle interaction coefficient, σ, was assumed. However, a better prediction of the results of Johnson and Kelsey was obtained by assuming that the particle interaction coefficient, σ, was a function of the number-average particle diameter, D₁, of the suspension mixture composition. Consequently, a new approach was identified to evaluate the simultaneous effects of small particles to both increase viscosity as a result of increasing particle interaction as well as to decrease viscosity as a result of improving the particle-size distribution. © 1993 John Wiley & Sons, Inc.     

Efficacy of Ozonated Water Against Erwinia carotovora subsp. carotovora in Brassica campestris ssp. chinensis

Erwinia carotovora subsp. carotovora (Ecc) is a bacterial pathogen that causes decay of vegetables and is found in a wide range of Brassica crops in the Shanghai area, particularly in non-heading Chinese cabbage (NHCC). In this study, aqueous ozone was used as an antimicrobial agent to prevent the growth of Ecc bacterial colonies. Ecc that were treated with aqueous ozone were completely inactivated after the bacteria had been exposed to 0.5 mg/L ozone at 28 °C. Furthermore, a susceptible NHCC cultivar was directly sprayed with different concentrations of dissolved ozonated water as a pesticide substitute. The effects of the treatments on morphology were analyzed, and some treatments were characterized by induction of visible symptoms of senescence. No negative effects were observed after treatment by spraying ozonated water compared with the control at concentrations below 8 mg/L. However, visible damage to leaves was observed after the plants were exposed to 10 mg/L ozonated water via spraying for 15 days during the plant reproductive stage. Additionally, enzyme activities and antioxidant responses gradually increased to a certain degree and then decreased in the untreated and ozonated water-treated plants. These results showed that ozonated water was effective in restraining pathogens and potentially defending against disease in growing NHCC plants within a certain concentration range. These results provide a theoretical basis for preventing disease by applying ozonated water to vegetables as an alternative to pesticides.     

Multiphase materials with lignin. IV. Blends of hydroxypropyl cellulose with lignin

Polymer blends of hydroxypropyl cellulose (HPC) and organosolv lignin (OSL) were prepared by mixing in solutions of both pyridine and dioxane, and casting as films, and by mixing in the melt followed by extrusion. All preparations exhibited partial miscibility as evidenced by a single T_g up to a composition of 40 wt % lignin above which phase separation was detected. Dioxane-cast and injection-molded blends were distinguished from the pyridine-cast materials by a positive T_g deviation from additivity, an approximation which adequately described the latter. This positive deviation in T_g is attributed to the formation of a liquid-crystal mesophase with a resultant reduction of amorphous HPC available for interaction with the lignin component. This explanation is supported by a rapid rise in modulus (～150%) and tensile strength with very low lignin content, and by an associated sharp decline in ultimate elongation. The development of morphological features, as observed by scanning electron microscopy provide further substantiation of this hypothesis.     

Torsional braid analysis of antioxidant activity in elastomer systems. I. Initial studies

The torsional braid apparatus as originally described by Lewis and Gillham has been explored as a means of providing a quantitative measure of antioxidant activity of selected compounds when formulated with certain elastomer systems prone to oxidative crosslinking on heat aging. With this technique the time dependence of the sharp torsional modulus increase, corresponding to a change from a rubbery to a highly crosslinked state, is determined. This time dependence is taken as a measure of the rate of oxidative crosslinking in heat-aged elastomer films coated on a fiber-glass braid. In this manner an assessment of the activity of antioxidants can be made. To illustrate the application of this technique, two initial studies will be cited. In one study the relative protective effect on a carboxylated styrene-butadiene latex system of a series of antioxidants was found to be in the following order: α, α′-2,6-bis(2-hydroxy-3-tert-butyl-5-methylphenyl)xylenol > the reaction product of nonylated paraethylphenol and formaldehyde > crude 2,2′-methylene bis(6-nonylparacresol). In another study, with cis-polybutadiene as the elastomer, the effectiveness of a series of antioxidants was found to be in the following order: 2,2′-methylene bis(6-tert-butyl paracresol) > 1,3,3,5-tetramethyl-1-m-tolylindane-4′,6-diol > 4,4′-methylene bis(2,6-di-tert-butylphenol). In addition, the effect of concentration and temperature was studied with the most efficient antioxidant in this last series.     

Tensile retraction measurements. IV. Determination of loose end pullout in gum vulcanizates

Tensile retraction measurements have been made on unfilled rubbers cured with either sulfur or dicumyl peroxide to different levels of crosslink density. The rubbers chosen were emulsion and solution polymerized anionic SBRs, cis-polybutadiene, natural rubber, and anionic 1,4-polybutadienes of different molecular weight. The measured molecular weight between crosslinks (M_c) at each extension gave a smooth curve when plotted against the maximum extension (Λ_max) used for the measurement. This curve was separated into three linear regions that characterize the cured rubber. The first region, above about 30% elongation, gave a Λ_max = 1 intercept that decreased with either increased polymer M_n or increased level of curatives. Subtracting this calculated crosslink density from the measured crosslink density below about 30% elongation gave another smooth curve when plotted against Λ_max. A second linear relationship was described in the general range of 5-30% elongation. Below about 5% elongation, a third linear relationship was found. This line was determined from the differences between the calculated and the observed crosslink densities in the lowest strain region of the intermediate strain plot. Possible explanations of these three linear regions have been made. Supporting evidence was gained from temperature-dependent experiments as well as from correlation of experimental results with polymers of different values of T_g.     

Evaluation of light-scattering detectors for size exclusion chromatography. II. Light-scattering equation selection

A new multiangle laser light-scattering (MALLS) detector for size exclusion chromatography promises simultaneous measurement of both weight-average molecular weight (M_w) and radius of gyration (r_g) at each retention volume across the chromatogram. However, there are a variety of ways of interpreting the raw data to provide these results. This study examines variations of three different rearrangements of the basic light-scattering equation. Data from a room temperature analysis of polystyrene and a high-temperature analysis of polyethylene were used. The degree of fit of each equation to the data and the precision of the M_w and r_g values are evaluated. To define precision, joint confidence regions (JCRs) were calculated and compared to simple confidence intervals based upon standard deviations in order to see the effect of interdependence of M_w and r_g. Results showed that the Debye equation was superior to the inverse Debye equation (similar to the Zimm plot) for the interpretation of MALLS data. The effect of the quantity of data included in the regression model was also assessed. Use of only the most precise four detector angles was compared to use of a full set of 15 angles. Precision of weight-average molecular weight values was found to be improved as the detector angle decreased because of the shortened extrapolation to zero angle. Precision at room temperature was much superior to that at high temperature. Use of simple confidence intervals was shown to provide only a fair approximation to the more accurate JCR. The “natural scatter” of data shown by the JCR generally shows the same trend as do plots in the literature of M_w vs. r_g. Thus, it is concluded that JCRs should be more often calculated in light-scattering studies in order to distinguish random scatter from meaningful correlations of these values. © 1993 John Wiley & Sons, Inc.     

Polymer degradation. V. Changes in molecular weight distributions during sonic irradiation of polyisobutene

Gel permeation chromatography was used to follow changes in the molecular weight distribution of a polyisobutene, initial M _v = 466,000, during degradation induced by sonic irradiation. Seven samples taken at times of 200–163,500 sec. were studied. In general, a steady decrease in molecular weight was observed, although a bimodal distribution was present after 20,000 sec. irradiation. Various measures of inhomogeneity, M _w/M _n, U, etc., were examined. The function, σ_n/M _w, where σ_n is the standard deviation of the number distribution, is considered as a measure of the relative distribution. It is shown to be almost constant throughout the degradation.     

Studies of reactions with polymers. III. Syntheses and properties of poly(vinyl alcohol) graft terpolymers

A condensation-coupling reaction through esterification is performed between the hydroxy groups of poly(vinyl alcohol) (PVA) and the anhydride groups of methyl methacrylate (MMA)-co-maleic anhydride (MA) copolymer to produce the PVA-g-MMA/MA graft terpolymer. The MMA-co-MA copolymer was obtained by copolymerization of MA and MMA in dimethyl sulfoxide by using azobisisobutyronitrile as initiator. The structure of reaction products was confirmed by infrared analysis, and the dependence of composition, viscosity, and yield of the graft terpolymer on the MA content in MMA-co-MA as well as the concentration of the reactants fed were investigated. Mechanical properties, water content, and gel content of the membranes of terpolymers were measured over a wide range of compositions. PVA-g-MMA/N-ethylol maleimide was also synthesized by reacting the residual anhydride groups on PVA-g-MMA/MA with ethanol amine, this reaction proceeds through the PVA-g-MMA/N-ethylol maleamic acid intermediate.     

Cure of epoxy novolacs with aromatic diamines. I. Vitrification,gelation, and reaction kinetics

The cure reaction of a commercial epoxidized novolac with 4,4' diaminodiphenylsulfone (DDS) was studied at constant cure temperatures in the range 120–270°C, as well as at constant heating rates (differential scanning calorimetry, DSC). Stoichiometric formulations did not attain complete conversion due to the presence of topological restrictions. The limiting conversion was x_max = 0.8. Samples containing an amine excess (≥ 20%) could be completely reacted, whereas this was not possible for formulations containing an epoxy excess. Samples containing a 20% amine excess showed the maximum value of the glass transition temperature (T_g230°C). Cure took place by epoxy-amine hydrogen reactions catalyzed by (OH) groups. A reactivity ratio of secondary to primary amine hydrogens equal to 0.2 was found. The activation energy was E = 61 kJ/mol, as arising from T_g versus time shift factors and time to gel measurements. A unique relationship between T_g and x could be obtained. Gelation took place at x_gel = 0.45 and the maximum T_g for the stoichiometric system was T_gmax = 215°C for x = 0.8. A conversion versus temperature transformation diagram was used to represent conditions where gelation, vitrification, degradation, and topological limitations took place. © 1993 John Wiley & Sons, Inc.     

Aggregation pheromone ofCarpophilus antiquus (Coleoptera: Nitidulidae) and kairomonal use ofC. lugubris pheromone byC. antiquus

Males ofCarpophilus antiquus Melsheimer (Coleoptera: Nitidulidae) emit an aggregation pheromone that was found to be a novel hydrocarbon, (3E,5E,7E,9E)-6,8-diethyl-4-methyl-3,5,7,9-dodecatetraene. A synthetic scheme and spectra (mass and proton NMR) are given for the compound. Beetles produced the pheromone when feeding on a variety of media, including the brewer's yeast-based artificial diet, fermenting whole-wheat bread dough, corn, and prunes; live baker's yeast was generally added to the food media. Males held individually produced, on average, 25 × more pheromone per beetle than males held in groups of 10 or more. Pheromone was not produced until males were at least 5 days old but was still detected from the oldest beetles tested (47 days). In field tests, the pheromone was attractive to both sexes ofC. antiquus, and it was synergized by food volatiles: A combination of pheromone and fermenting whole wheat dough attracted 2.5× more beetles than pheromone alone, but dough by itself was not significantly more attractive than the control. Semiochemical interactions were studied amongC. antiquus and two other sympatric species for which pheromones are known,C. lugubris Murray andC. freemani Dobson.C. antiquus responded readily to the pheromone ofC. lugubris, but all other interspecific responses to the pheromones were weak. In a sample of naturally infested corn ears, the presence ofC. antiquus was strongly associated with the presence ofC. lugubris, as would be expected if the pheromone ofC. lugubris serves as a kairomone forC. antiquus.     

Investigations on nylon 4 membranes. Synthesis and transport properties. I. Synthesis of nylon 4 polymer

The synthesis of nylon 4 (polypyrrolidone) by the anionic polymerization of 2-pyrrolidone through the use of the CO₂/potassium pyrrolidonate catalyst system for use in preparing polymer membranes for separation purposes was investigated in detail. The effects of the quantity of CO₂, the potassium pyrrolidonate catalyst, and the reaction temperature on the yield and molecular weights of the nylon 4 were studied. At reaction temperatures of 50°C and a reaction time of 120 hr, a yield of 50.9% with intrinsic viscosity of 4.42 (corresponding to M_n of 108,200 and M_w of 135,850) was obtained. The molecular weight distributions of the nylon 4 were determined by gel permeation chromatography (GPC) using m-cresol as the eluting solvent and were found to have a relatively narrow distribution.