Abstract  Dielectric relaxation spectra of two closely related glass formers, dipropylene glycol [H-(C3H6O)2-OH] and dipropylene glycol dimethyl ether [CH3-O-(C3H6O)2-CH3], were measured at ambient and elevated pressures in the supercooled and the glassy states are presented. Hydrogen bonds formed in dipropylene glycol are removed when its ends are replaced by two methyl groups to become dipropylene glycol dimethyl ether. In the process, the primary relaxation, the excess wing, and the resolved secondary relaxation of dipropylene glycol are all modified when the structure is transformed to become dipropylene glycol dimethyl ether. The modifications include the pressure and temperature dependences of these relaxation processes and their interrelations. Thus, by comparing the dielectric spectra of these two closely related glass formers at ambient and elevated pressures, the differences in the relaxation dynamics and properties in the presence and absence of hydrogen bonding are identified.

Abstract  Ferulic acid (F.A) receives significant interest in the beauty industry with regard to its skin-whitening and anti-oxidant properties. However, its use in cosmetics is limited due to pH- and temperature-related instabilities. In this study, we investigated the stability of F.A in eight different prototype formulae. The results confirmed that in our conditions the stability of F.A is pH- and temperature-related. Additionally, the nature of the solvent dipropylene glycol (DPPG) showed a capacity to stabilize F.A. A series of experiments was further planned for studying the mechanism of degradation of F.A. In a prototype of a cosmetic medium, F.A degrades first through a decarboxylation step, leading to 4-hydroxy-3-methoxystyrene (PVG). Further, F.A and PVG are both involved in an additional reaction, resulting in the trans-conjugation dimer of PVG. The consequences of these results in formulating F.A are discussed.

Abstract  Propylene carbonate and a mixture of two secondary amides, N-methylformamide and N-ethylacetamide, are investigated by means of broadband dielectric and mechanical shear spectroscopy. The similarities between the rheological and the dielectric responses of these liquids and of the previously investigated tripropylene glycol are discussed within a simple approach that employs an electrical circuit for describing the frequency-dependent behavior of viscous materials. The circuit is equivalent to the Gemant-DiMarzio-Bishop model, but allows for a negative capacitive element. The circuit can be used to calculate the dielectric from the mechanical response and vice versa. Using a single parameter for a given system, good agreement between model calculations and experimental data is achieved for the entire relaxation spectra, including secondary relaxations and the Debye-like dielectric peak in the secondary amides. In addition, the predictions of the shoving model are confirmed for the investigated liquids.

Abstract  Central dosing units for surface disinfectants can constitute a particular hygiene problem in hospitals if a biofilm can develop in the piping system despite the disinfectant solution that is present. In earlier studies it was able to be shown that oxygen-releasing compounds in particular were highly effective against microorganisms in generated biofilms. The purpose of the study presented was to investigate in a test simulating practical conditions whether, in addition to the described good effect, peroxide-containing solutions also have a uniform effect against all isolates from disinfectant use-solutions, or whether there are differences. The results show that a 1% H2O2 solution (C) was not sufficiently effective against all test organisms after a contact time of one hour. In contrast, the 1% test solution of A (10% perglutaric acid, 28% H2O2, < 0.5% perbenzoic acid) was highly and uniformly effective. The 3% test solution of B (10% tertiary butylhydroperoxide, 20% phenoxypropanols, 48% dipropylene glycol) exhibited weaknesses against some test organisms after the one-hour contact time. After a contact time of three hours, this solution, unlike the 1% H2O2 solution achieved a reduction in bacterial count of more than 5 log steps against all species. On the basis of these results, before cleaning piping systems it appears advisable to test the effectiveness of the solution to be used in a suitable test with the isolates.

Abstract  Dipropylene glycol dibenzoate (Benzoflex) 9 multiplied by 88) (C sub(20)H sub(22)O sub(5)) is a primary plasticizer. It has a low order of toxicity, is biodegradable and is rapidly eliminated by mammals. The effect of Benzoflex 9 multiplied by 88 on microbial functions was mixed (cellulose degradation, urea degradation and sulfate reduction). Its octanol-water partition coefficient is 455 plus or minus 15. It was not mutagenic in the Ames test and the Saccharomyces) test.

Abstract  Dipropylene glycol (DG) has been considered safe to use as a solvent in perfumes and other cosmetics (1). Our recent case of allergic contact dermatitis from DG in a hand lotion (2) prompted this further study. Materials and Methods: We used standard (S) DG (synthesis grade purity >97%) from E. Merck (Darmstadt, Germany) and cosmetic grade (CG) DG (purity 96%) from our case (2). In a pilot study, 34 eczema patients were patch tested with either S or CG DG at 10%, 5%, 2% and 1% aq. When no reactions were seen, the standard series at Gentofte was supplemented with DG 10% aq., S and CG, for 7 months (25.1.94- 25.8.94). 503 consecutive eczema patients, 212 men and 291 women, were tested, patches being applied for 2 days, using Scanpor tape and Finn Chambers, and reactions being read at D2, D3 and 05-7. The original patient (2) was repatch tested with both S and CG DG at I% and 0.5% aq. Results: 6. 7% (34/503) of the patients reacted to at least 1 of S and CG DG (Table 1). There was l positive patch test reaction to S DG, the remaining reactions being either ?+, 5.1% (26/503), or IR, 1.4% (7/503) (no sex difference). 10 of those with ?+ reactions to DG were also tested with their own cosmetics and 2 reacted, l to mascara, skin tonic and eye shadow, and I to camomile liniment (DG contents not determined). The original patient (2) had + + and + + + reactions to CG DG, as well as to S DG, 0.5% and 1% aq. Discussion: DG is a mixture of 3 isomers (1), their distribution in the 2 grades used in this study differing as determined by GC/MS (2). The original patient (2) reacted to both grades and no difference was found between the frequency of reactions to the 2 grades in 503 consecutive eczema patients. Only 1 patient out of 503 (0.2%), however, had a definitely positive patch test reaction to DG, its clinical relevance not being established. Patch testing with other grades of DG used in cosmetics (I) might give different results, but at present, we consider contact allergy to dipropylene glycol to be rare in our study population.

Abstract    Ion mobility spectrometry (IMS) affords miniaturized hand-held devices that can be used for monitoring and remote measurement. Because such instruments have limits on storage capacity or bandwidth for wireless transmission, data compression is important Furthermore, all instruments should be operated with the fastest possible sampling rates because a signal-to-noise gain can be achieved by wavelet compression. Linear wavelet compression (LWC) applied to IMS data may cause peak distortion when the spectra are reconstructed. Nonlinear wavelet compression (NLWC) precisely preserves the peak location (i.e., drift time), height, and shape. IMS data of three chemical warfare simulants, dimethyl methylphosphonate, triethyl phosphate, and dipropyleneglycol monomethyl ether, were collected from an Ion Track ITEMISER and a Graseby Ionics detector CAM. Two-dimensional NLWC was used to compress the IMS data in the drift time and data acquisition dimensions on IMS data of chemical warfare simulants. NLWC was applied to achieve a compression factor of 1/128 with relative error of root-mean-square of <0.25% in the reconstructed spectra. A method was also developed and evaluated for optimizing compression. [PUBLICATION ABSTRACT]

Abstract  Pesticide spray formulations include a variety of adjuvants as wetting agents, surfactants or emulsifiers. DOWANOL TPM (tripropylene glycol methylether) is one such adjuvant in current common use in spray formulations of the insecticide fenitrothion. Unlike some other adjuvants which the authors have tested, DOWANOL appears to have no significant toxicity for duckweed, Lemna minor L., an environmentally important aquatic plant, which has been previously shown to be sensitive to some formulations. Four parameters were monitored, namely, biomass, photosynthetic function, adenosine triphosphate level and changes in the electrical potential of the bathing media. Reported concentrations of DOWANOL in forest pools after spraying are of the order of 1 mu g ml super(-1).

Abstract  In this work a fast liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method using a C18 Fused Core[TM] column, was developed for the simultaneous analysis of bisphenol A diglycidyl ether (BADGE), bisphenol A (2,3-dihydroxypropyl) glycidyl ether (BADGE super(.H) sub(2)O), bisphenol A bis(2,3-dihydroxypropyl) ether (BADGE super(.2H) sub(2)O), bisphenol A (3-chloro-2-hydroxypropyl) glycidyl ether (BADGE super(.HCl), bisphenol A bis(3-chloro-2-hydroxypropyl) ether (BADGE) super(.)2HCl) and bisphenol A (3-chloro-2-hydroxypropyl)(2,3-dihydroxypropyl ether) (BADGE super(.HCl) super(.)H sub(2O) and bisphenol F diglycidyl ether (BFDGE), bisphenol F bis(2,3-dihydroxypropyl) ether (BFDGE) super(.)2H sub(2O), bisphenol F bis(3-chloro-2-hydroxypropyl) ether (BFDGE) super(.)2HCl). The LC method was coupled with a triple quadrupole mass spectrometer, using an ES delta source in positive mode and using the [M+NH sub(4][super]+ adduct as precursor ion for tandem mass spectrometry experiments. The method developed was applied to the determination of these compounds in canned soft drinks and canned food. OASIS HLB solid phase extraction (SPE) cartridges were used for the analysis of soft drinks, while solid canned food was extracted with ethyl acetate. Method limits of quantitation ranged from 0.13 [micro]g L[super]-1 to 1.6 [micro]g L[super]-1 in soft drinks and 1.0 [micro]g kg[super]-1 to 4.0 [micro]g kg[super]-1 in food samples. BADGE) super(.)2H sub(2O was detected in all the analyzed samples, while other BADGEs such as BADGE) super(.)H sub(2O, BADGE) super(.)HCl super(.H) sub(2)O, BADGE super(.HCl and BADGE) super(.)2HCl were also detected in canned foods.

Abstract  The synthesis of telechelic polyacetals with terminal hydroxyl groups (polyacetal polyols), by the reaction of triethylene glycol divinyl ether with dipropylene glycol in the presence of trimethylolpropane or other triols or diols as starters, in acidic catalysis, has been studied. The synthesized liquid polyacetal triols and polyacetal diols were characterized by hydroxyl number, viscosity, acidity, number average molecular weight (M sub(n)), weight average molecular weight (M sub(w)), molecular weight distribution (M sub(w)/M sub(n)), FT-IR spectra. The obtained polyacetals were transformed in cast elastomers by the reaction with the isocyanate Mondur CD (modified diphenyl methane diisocyanate) with properties very close to the elastic polyurethanes obtained by using conventional polyether triols, copolymers propylene oxide-ethylene oxide. The polyacetal polyols are suitable for the synthesis of elastic polyurethanes (polyurethane elastomers, flexible polyurethane foams). Polyacetals are well known biodegradable polymers. Therefore, the polyurethanes based on polyacetal polyols are expected to be biodegradable.

Abstract  Absorption across full thickness human skin was evaluated in vitro for five selected glycol ethers. Skin membranes were settled on static diffusion cells and both neat and 50% water diluted glycol ethers were applied on the donor chamber for 8 h. The amount of glycol ethers permeated into the receptor fluid was measured by gas chromatograph equipped with flame ionization detector (GC- FID). For neat solvents, permeation coefficient K sub(p) ranged from 0.06 to 0.83 cm h super(-1) 10 super(-3) respectively for DEGBEA and EGMEA while for 50% v/v diluted glycol ethers it varied from 0.08 to 1.81 cm h super(-1) 10 super(-3) respectively for DPGME and EGMEA. These experiments show a statistically significant (Student's t-test, P<0.05) increase in permeation coefficients from neat to 50% water diluted glycol ethers and the same trend can be observed in fluxes and lag times. Only DPGME show an opposite behaviour. These results confirm the good ability of these solvents of permeating the skin and show that they could represent a risk for their potential dermal absorption both for workers and for occasional exposures, since the average lag time is 1.57 h.

Abstract  Male Fischer 344 rats were given a single oral dose of approximately 1289 mg/kg (8.7 mmol/kg) of ( super(14)C)DPGME. After dosing, expired air, excreta, and tissues were analyzed for super(14)C activity, and metabolites in urine were isolated and identified. Approximately 60% of the administered super(14)C activity was excreted in urine, while 27% was eliminated as super(14)CO sub(2) within 48 hr after dosing. DPGME, PGME, dipropylene glycol, propylene glycol, as well as sulfate and glucuronide conjugates of DPGME were identified in urine of animals given ( super(14)C)DPGME. Results of the study indicate that DPGME is metabolized via the same routes to the same general types of metabolites as previously identified for propylene glycol monomethyl ether (PGME).

Abstract  The applicability of multidimensional gas chromatography-mass spectrometry to the analysis of five glycol ethers in air was demonstrated. Air samples were collected on charcoal tubes and desorbed with 5% methanol in methylene chloride as is described in method 1403 of the National Institute for Occupational Safety and Health Manual of Analytical Methods. The glycol ethers were determined by multidimensional gas chromatography-mass spectrometry. The limit of detection was 5 to 7 micrograms/sample for each compound.

Abstract  In the present contribution, the properties of dipropylene glycol isobornyl ether (Pribelance) are discussed, especially in the context of microemulsion and emulsion formulations. Pribelance is a new low-toxic anti-foaming hydrotrope with excellent co-surfactant properties that has some similarities with long-chain alcohols, but in contrast to them, it is liquid at room temperature. In combination with another, more hydrophilic co-surfactant, it allows significant amounts of oil to be solubilized in water. Possible applications such as in cosmetics, as an anti-foaming agent or as additive to cooling lubricants are discussed. Further potential applications are plasticizers, fermentation systems, agrochemicals and waste-water treatments.

Abstract  Purpose - The purpose of this paper is to synthesise environment friendly UV curable polyurethane acrylate resins for various industrial applications and study the performance properties of the cured coating films applied over metal surfaces.

Design/methodology/approach - The polyurethane acrylate resin was synthesised using polyester polyol (synthesised using ethylene glycol, adipic acid and 1,6 hexane diol), isophorone diisocynate (IPDI) and 2-hydroxy ethyl methacrylate (HEMA). The different formulations were developed using various reactive diluents viz. monofunctional, difunctional, trifunctional and tetrafunctional (ethoxylated phenol monoacrylate, 1, 6 hexane diol di acrylate, dipropylene glycol di acrylate, trimethylol propane triacrylate, propoxylated trimethylol propane triacrylate, pentaerythrol triacrylate - PETA). These samples were cured under UV radiation. For effective curing, various compositions of oligomers, photoinitiator and reactive diluents were used. The mechanical, optical, rheological, chemical and stain resistance properties were evaluated.

Findings - The designed polyurethane acrylate gave good performance properties when used with reactive diluents having different functionality in different ratios for application over metal surfaces as protective coatings for various industrial applications. While using reactive diluents, the coating compositions showed significant enhancement of mechanical, physical and chemical resistance properties. Owing to different functionality of reactive diluents used, highly cross-linked structures are formed, which lead to excellent mechanical and chemical properties. The optimum results were obtained with PETA as reactive diluent.

Research limitations/implications - The polyurethane resin has been synthesised from polyester polyol (made up of ethylene glycol, adipic acid and 1, 6 hexane diol), IPDI, 2-HEMA. Besides, this, it can be synthesised from some other polyester polyol or polyether polyol. In addition to this, some other isocyanates such as TDI, MDI, HDI, HMDI, etc. may be used.

Practical implications - The study has provided a better solution for developing low volatile organic compound (VOC) products by using UV radiations, which can be cured within a minimum period of time and can save significant application curing time for the end-users. The developed product is also an environmentally friendly product.

Originality/value - Metallic surfaces are widely used in packaging industry in rigid and semi-rigid forms. One of the prime requirements of the surface is an attractive printing on it. Conventionally used coating system on metallic surfaces are not holding or retaining their decorative effect/gloss level to a large extent. For this purpose, an overprint varnish is normally used which is mostly solvent based. This paper has been able to suggest very good formulations for printing of metallic surfaces for packaging and for overprinting in particular, which is radiation curable and environment friendly.

Abstract  326 healthy couples were selected to enter the trial of a new intravaginal contraceptive called the TA-RO CAP. The trial lasted three years. Clinical and laboratory examinations were performed periodically to determine the long-term effectiveness, tolerability and acceptance. Statistical evaluation of results was performed by life-table analysis.

Abstract  Poly(ethylene terephthalate) was degraded by transestrification with oligoesters made by conversion of azelaic or adipic acid, glycerol, diethylene or dipropylene glycol and 2-ethylhexanol at 190-210 degrees C to resp. oligoterephthalates used then as plasticizers of poly(vinyl chloride) (PVC). Use of the plasticizers resulted in an improvement of mech. properties of PVC.

Abstract  Toxline abstract: Rept. for 19 Jun-12 Sep 90. See also PB92-196179. Sponsored by National Toxicology Program, Research Triangle Park, NC. The laboratory supplement accompanying a report on the developmental toxicity of dipropylene glycol provides test methods used in the study, as well as information on breeding and caring for the test rats. Detailed chemical analysis methods are also provided.