Effects of post cure treatment in the glass transformation range on the structure and fire behavior of in situ generated siilica/epoxy hybrids

A new "in situ” sol–gel synthesis procedure was exploited to produce silica/epoxy nanocomposites with 6 wt.% maximum silica content. 3-Aminopropyltriethoxysilane (APTS) was used as a coupling agent. The experimental results (fourier- transform infrared spectroscopy, FTIR, small-angle X-ray scattering, SAXS, transmission electron microscopy, TEM, nuclear magnetic resonance, NMR, and dynamic mechanical analysis, DMA) support that the structure consists of nanosized silica particles (maximum 1.25 nm in size) embedded in a hybrid co-continuous network. A post cure non-isothermal heating from 15 to 100 °C (beyond the Tg of the neat epoxy) caused Tg and storage modulus to increase. The fire behavior, that, owing to severe regulations (i.e., in aerospace engineering), often prevents composites applications, was also studied. The formed silica domains prevented melt dripping phenomena during vertical flame spread tests. Cone calorimetry tests showed a remarkable decrease of the heat release rate (HRR) for all the hybrid systems with respect to the neat cured resin, even at very low silica loadings (i.e., 2 wt.%). This decrease was much more pronounced for the hybrid structures that were not subjected to the post cure thermal treatment. The use of multiple structural investigation techniques allowed to choose among multiple hypothesis and conclude that nanoparticles clustering is the main reason of the effects of the post curing treatments

Skene gland cyst in post puberal girl

The finding of an interlabial mass in a girl can create doubts in relation to its etiology, its implications and its management.Skene cysts are an unusually rare at any age, but especially in a girl in post-pubertal age as well as in adult women.Because these lesions can simulate other lesions with important clinical implications, careful urological evaluation is required.Several paraurethral glands are described, Skene's glands are the largest and are located on the distal urethral floor.The incidence of Skene cysts is probably much higher than estimated due to a lack of systematic reporting of their finding.We performed a literature evaluation regarding the reporting of Skene cysts in children and adults.We report the case of a voluminous interlabial mass found in a girl in post-puberal age, the characteristic displacement of the urethral meatus confirmed the suspicion of Skene's parauthral cyst.Skene cysts management tends to be conservative when seen in the newborn, while a surgical approach in the young adult is preferable

Urachal cyst abscess in an infant

Urachal anomalies are rare, in the literature it is reported that the three most common types of urachal anomalies are urachal cysts, urachal sinus, and urachal diverticulum. We present the case of an infant who has come to our observation with painful umbilical mass and purulent discharge, irritability and fever. The suspicion of abscess of urachal sinus was confirmed by ultrasound examination, the VCUG was performed to exclude urinary abnormalities. Surgical removal of urachal sinus was resolutive without complications in follow-up. Keywords: Urachal anomalies, Patent urachus, Urachal abscess, Urachal sinus, Umbilical abscess, Diagnosis, Treatment, Children, Infectio

Silica treatments: A fire retardant strategy for hemp fabric/epoxy composites

In this paper, for the first time, inexpensive waterglass solutions are exploited as a new, simple and ecofriendly chemical approach for promoting the formation of a silica-based coating on hemp fabrics, able to act as a thermal shield and to protect the latter from heat sources. Fourier Transform Infrared (FTIR) and solid-state Nuclear Magnetic Resonance (NMR) analysis confirm the formation of -C-O-Si- covalent bonds between the coating and the cellulosic substrate. The proposed waterglass treatment, which is resistant to washing, seems to be very effective for improving the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate. In particular, the exploitation of hemp surface treatment and Ammonium Polyphosphate (APP) addition to epoxy favors a remarkable decrease of the Heat Release Rate (HRR), Total Heat Release (THR), Total Smoke Release (TSR) and Specific Extinction Area (SEA) (respectively by 83%, 35%, 45% and 44%) as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char, as also assessed by Thermogravimetric Analysis (TGA). Because of the low interfacial adhesion between the fabrics and the epoxy matrix, the obtained composites show low strength and stiffness; however, the energy absorbed by the material is higher when using treated hemp. The presence of APP in the epoxy matrix does not affect the mechanical behavior of the composites

Flame retardancy and mechanical properties of ecofriendly coated hemp fabrics/epoxy composites

A new and ecofriendly chemical approach uses inexpensive waterglass solutions in order to promote the formation of a silica-based coating on hemp fabrics; this green coating is able to act as a thermal shield and to protect the latter from heat sources. The waterglass treatment improves the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate, and favors a remarkable decrease of the heat release rate, total heat release, total smoke release and specific extinction area (respectively by 83%, 35%, 45% and 44%) as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char