The kinetics of the thermal decomposition reaction of diethyl ketone triperoxide (3,3,6,6,9,9‐hexaethyl‐1,2,4,5,7,8‐hexaoxacyclononane, DEKT) in chlorobenzene solution were studied in the temperature range 99.0–148.0°C and at initial concentrations of (1.65–4.97) × 10−2 M. The thermolysis of DEKT follows a first‐order kinetic law up to at least ca 80% triperoxide conversion. The activation parameter values for the initial O—O bond rupture in chlorobenzene (ΔH‡=134.6±1.7 kJ mol−1; ΔS‡ = 4.2 ± 3.8 J mol−1 K−1) and the reaction products observed support a stepwise reaction mechanism which includes as a first step the unimolecular homolytic cleavage of one peroxidic bond of the DEKT molecule giving rise to a biradical as intermediate. Additionally, the results obtained were compared with those obtained in toluene, toluene–styrene (50%, v/v) and chlorobenzene–styrene (50%, v/v) solution, showing that the decomposition reaction is strongly solvent dependant. Further, the biradical intermediate obtained in all cases was used to initiate styrene polymerization. It was demonstrated that DEKT can effectively act as initiator in styrene polymerization and its performance is similar to that presented by a multifunctional initiator giving rise to high molecular weight polystyrene at a high reaction rate. Copyright © 2004 John Wiley & Sons, Ltd.

Copolymers of l-lactide and poly(propylene glycol) diglycidyl ether (PPGDGE380) were synthesized by ring opening polymerization (ROP). Stannous octoate was used as the catalyst and 1-dodecanol as the initiator. The effect of the variables on the thermal properties of the copolymers was investigated by differential scanning calorimetry (DSC). Contact angle measurements were made in order to study the wettability of the synthesized copolymers. The copolymers differed widely in their physical characteristics, ranging from weak elastomers to tougher thermoplastics, according to the ratio of l-lactide and PPGDGE380. The results showed that the copolymers were more hydrophilic than neat Poly(lactide) (PLA) and the monomer ratio had a strong influence on the hydrophilic properties.

Objectives: To determine the association between mean airway pressure and 90-day mortality in patients with acute respiratory failure requiring mechanical ventilation and to compare the predictive ability of mean airway pressure compared with inspiratory plateau pressure and driving pressure. Design: Prospective observational cohort. Setting: Five ICUs in Lima, Peru. Subjects: Adults requiring invasive mechanical ventilation via endotracheal tube for acute respiratory failure. Interventions: None. Measurements and Main Results: Of potentially eligible participants (n = 1,500), 65 (4%) were missing baseline mean airway pressure, while 352 (23.5%) were missing baseline plateau pressure and driving pressure. Ultimately, 1,429 participants were included in the analysis with an average age of 59 ± 19 years, 45% female, and a mean Pao 2/Fio 2 ratio of 248 ± 147 mm Hg at baseline. Overall, 90-day mortality was 50.4%. Median baseline mean airway pressure was 13 cm H2O (interquartile range, 10–16 cm H2O) in participants who died compared to a median mean airway pressure of 12 cm H2O (interquartile range, 10–14 cm H2O) in participants who survived greater than 90 days (p < 0.001). Mean airway pressure was independently associated with 90-day mortality (odds ratio, 1.38 for difference comparing the 75th to the 25th percentile for mean airway pressure; 95% CI, 1.10–1.74) after adjusting for age, sex, baseline Acute Physiology and Chronic Health Evaluation III, baseline Pao 2/Fio 2 (modeled with restricted cubic spline), baseline positive end-expiratory pressure, baseline tidal volume, and hospital site. In predicting 90-day mortality, baseline mean airway pressure demonstrated similar discriminative ability (adjusted area under the curve = 0.69) and calibration characteristics as baseline plateau pressure and driving pressure. Conclusions: In a multicenter prospective cohort, baseline mean airway pressure was independently associated with 90-day mortality in mechanically ventilated participants and predicts mortality similarly to plateau pressure and driving pressure. Because mean airway pressure is readily available on all mechanically ventilated patients and all ventilator modes, it is a potentially more useful predictor of mortality in acute respiratory failure.

The title molecule (diethyl ketone triperoxide, DEKTP), C(15)H(30)O(6), is a cyclic triperoxide closely related to triacetone triperoxide (TATP), one of the most unstable explosives known. However, the stability of DEKTP is ca 20-50 times greater than that of TATP. DEKTP crystallizes with two molecules in the asymmetric unit, with virtually identical geometry. The cyclononane core is stabilized in a twisted boat-chair conformation (approximate D(3) symmetry), very close to that previously described for TATP. The explanation for the safe thermal behaviour of DEKTP compared with TATP should thus not be sought in the molecular dimensions, but rather in the thermal decomposition kinetics.

To analyze the influence of the percentage of glycidyl methacrylate (GMA) coupled with polymeric chains to determine their effect on molecular weight (M w ) and refractive index (n D ), a Mixture Design of Experiments (MDOE) has been used. A ''d'' optimal mixture design for four components was used for planning the runs and analyzing the information using statistical tools. The prototypes generated were synthesized using styrene (St) 73-89.98%, methylmethacrylate (MMA) 8-22%, and glydicyl methacrylate (GMA) 2-10% at different ratios according to the experiment design. In this sense, the prototypes are terpolymers (St-MMA-GMA). According to the desired properties of the prototypes reviewed in literature and market studies, this is expressed in materials with a preferred n D (ca. 1.5750-1.5894) and molecular weight (ca. 300,000 g/mol) the ratios were established. In a radical polymerization process using a commercial initiator (Trigonox 22E-50) and a temperature program (120-200 C) simulating an industrial process, the polymerization reactions were conducted. The detailed information derived from DOE here is presented.