Synergistic Effect of APP and TBC Fire-Retardants on the Physico-Mechanical Properties of Strandboard

This study explored the feasibility of fabricating fire-retardant strandboard with low mechanical properties deterioration to the physico-mechanical properties. A hybrid fire-retardant system of ammonium polyphosphate (APP) and 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione (TBC) was investigated. Thermogravimetric analysis results show that both APP and TBC enhance the thermal stability and incombustibility of wood strands. An infrared spectrum was applied to investigate the effect of flame retardants on the curing behaviors of polymeric diphenylmethane diisocyanate (PMDI) resin. Based on the results of limiting oxygen index (LOI) and Cone calorimetry (CONE), APP and TBC both lead to a higher fire retardancy to strandboard. It is worth mentioning that the two flame retardants lead to evidently differential influences on the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), and water-soaking thickness swelling (TS) properties of strandboard. Hence, a hybrid flame retardant is prominent in manufacturing strandboard with both good fire retardant and satisfying physico-mechanical properties.

Flame Retardant Properties and Mechanical Properties of Polypropylene with Halogen and Halogen-Free Flame Retardant System

In this study, to improve the flame retardancy properties of polypropylene, DBDPE/Sb2O3 and DBDPE/HBCD/Sb2O3 flame retardant systems were used for flame retardant PP, and a halogen-free flame retardant PP material was prepared using the one-component intumescent flame retardant PNP1D. Tensile tests, impact tests, ultimate oxygen index, UL94V-0 vertical combustion, thermogravimetric analysis, rheological analysis and scanning electron microscopy were used to study the flame retardant properties and mechanical properties of the flame retardant PP. The test results show that both the ultimate oxygen index of DBDPE/Sb2O3 compounded flame retardant PP and the ultimate oxygen index of PNP1D flame retardant PP are nearly double that of pure PP, passing the UL-94V-0 flame retardant standard. The thermal decomposition temperature range of DBDPE/Sb2O3 compounded system and the thermal decomposition temperature range of PNP1D flame retardant PP both completely cover the thermal decomposition temperature range of both the DBDPE/Sb2O3 compound system and PNP1D flame retardant PP completely covered the thermal decomposition temperature range of pure PP. The tensile and impact strength of the DBDPE/Sb2O3 flame retardant system with 10% SK-80 is 50% higher than that of the DBDPE/Sb2O3 flame retardant system without SK-80. The modified PP with 25% PNP1D is nearly 1 time higher than pure PP in terms of carbon formation and has an ideal flame retardant effect.

Bio-Based Rigid Polyurethane Foams Modified with Phosphorus Flame Retardants

Rigid polyurethane foams (RPURF) containing a bio-polyol from rapeseed oil and different phosphorus-based flame retardants were obtained. Triethyl phosphate (TEP), dimethyl propane phosphonate (DMPP) and cyclic phosphonates Addforce CT 901 (20 parts per hundred polyol by weight) were used in the synthesis of RPURF. The influence of used flame retardants on foaming process, cell structure, and physical–mechanical properties as well as flammability of RPURF were examined. The addition of flame retardants influenced the parameters of the cellular structure and decreased compressive strength. All obtained foam materials had a low thermal conductivity coefficient, which allows them to be used as thermal insulation. The research results of bio-based RPURF were compared with foams obtained without bio-polyol. All modified materials had an oxygen index above 21 vol%; therefore, they can be classified as self-extinguishing materials. The analysis of parameters obtained after the cone calorimeter test showed that the modified RPURF have a lower tendency to fire development compared to the reference foams, which was particularly noticeable for the materials with the addition of DMPP.

Glucose-Derived Carbon Nanospheres as Flame Retardant for Polyethylene Terephthalate

To improve the flame retardant properties of polyethylene terephthalate (PET), glucose-derived carbon nanospheres (CNSs) were synthesized and introduced into PET matrix. The thermal property and flame retardancy of CNSs/PET composites were thoroughly investigated. Results showed that CNSs displayed good flame-retardant performance for PET. When blended with only 1.0 wt.% of CNSs, CNSs/PET exhibited a limiting oxygen index (LOI) of 26.3 and a vertical combustion class of V-2, and its peak-heat release rate (pk-HRR) was reduced by 41.6%. Importantly, the initial decomposition temperature and the maximum weight loss temperature of CNSs/PET were 52°C and 199°C higher than those of PET, respectively. Furthermore, a condensed phase flame-retardant mechanism appeared in CNSs/PET, which formed a dense and thermally stable protective char layer during combustion. Overall, this study disclosed the flame-retardant potential and possible mechanism of CNSs for polyesters, which would benefit the development of carbon-based materials and flame-retardant polymers.

INVESTIGATES THE INFLUENCE PHOSPHORUS-NITROGEN-CONTAINING ANTIPYRENES ON THERMAL STABILITY AND FLAME RETARDANCY OF POLYURETHANE FOAM

The paper investigates the influence of melamine and ammonium polyphosphates on thermal degradation and flame retardancy of polyurethane foams (PUFs) composites, based on phosphorus-containing polyol. The limiting oxygen index of PUF was increased from 27,5 to 31,5 vol. % as compared to PUF composites based on phosphorus-containing polyol. The TGA of polyurethane foams demonstrated an increase of the thermal stability. Synthesized polyurethane foams have the highest category of combustion resistance.

Polybenzoxazine Resins with Cellulose Phosphide: Preparation, Flame Retardancy and Mechanisms

Phosphated cellulose (PCF) was synthesized based on urea, phosphated acid and cellulose. The structure of the PCF was confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy coupled with the Energy Dispersive Spectrometer (SEM-EDS). Benzoxazine (Ba)/PCF hybrid materials were fabricated and thermally cured to prepare polybenzoxazine composites (PBa/PCF). The effects of PCF on the curing temperature of Ba were analyzed through differential scanning calorimetry (DSC). The thermogravimetric (TGA) results demonstrated an increased char residue of 50% for the PBa composites incorporating PCF-5% compared with the pure PBa. The peak heat release rate (PHRR) and total heat release (THR) values of the PBa/PCF-5% composites clearly decreased by 58.1% and 16.5% compared to those of the pristine PBa. The smoke released from the PBa/PCF system significantly reduced with the loading of PCF. Moreover, the limited oxygen index (LOI) and vertical burning test level (UL-94) of PBa/PCF-5% reached up to 31 and V0. The flame retardant mechanism of the PCF in the PBa matrix was investigated TG-FTIR and char residues analysis. Finally, the dynamical mechanical analysis (DMA) results demonstrated that the Tg of the PBa/PCF composites was approximately 230 °C, which does not affect further applications of PBa composites.

The Use of Copper Oxides as Cross-Linking Substances for Chloroprene Rubber and Study of the Vulcanizates Properties. Part II. The Effect of Filler Type on the Properties of CR Products

The properties of rubber materials are dependent on the characteristics of the elastomer matrix, the filler type, the cross-linking agent, the number of ingredients, and their interactions. In the previous article, we showed that chloroprene rubber can be efficiently cross-linked with copper(I) oxide or copper(II) oxide. During the processing of rubber compounds, the incorporation of a filler and a curing substance are two substantial parameters, such as the homogeneity of mixing and cross-linking that significantly affect the properties of the vulcanizates. Therefore, this work aimed to evaluate the curing characteristics, mechanical and dynamical properties, morphology, and flammability of the composites containing chloroprene rubber cross-linked with Cu2O or CuO and filled with different fillers (silica, carbon black, montmorillonite, kaolin, chalk). It was found that the type of filler and curing agent had a significant impact on the degree of cross-linking of the chloroprene rubber and the properties of its vulcanizates. The degree and speed of the cross-linking of filled CR were higher when the CR was cured with copper(II) oxide. Among the fillers used, the presence of carbon black or silica ensured the highest degree of CR cross-linking and the most useful properties. The flammability tests indicated that all produced vulcanizates were characterized by a high oxygen index, which allows them to be classified as non-flammable materials.

Correlation and prediction of oxygen index from oxygen saturation index in neonates with acute respiratory failure

Objective: To evaluate the correlation between the oxygen index (OI) and the oxygen saturation index (OSI, measured by pulse oximetry and noninvasively) in neonates with acute respiratory failure and to predict the OI from the OSI. Study Design: A retrospective cohort study was conducted in neonates requiring invasive mechanical ventilation who had arterial blood gas between 2018 to 2019 at a neonatal intensive care unit. The correlation between OI and OSI was analyzed by using the Pearson correlation coefficient. Results: A total of 636 measurements from 68 neonates (35 preterm and 33 terms) were recruited into the study. There was a strong correlation between the OI and the OSI (r = 0.90) in all neonates. The correlation between the OI and the OSI in persistent pulmonary hypertension of the newborn, congenital cyanotic heart disease, and other causes of respiratory failure also showed a strong correlation (r = 0.88, 0.93, and 0.88, respectively). The correlation was strong in neonates with an oxygen saturation less than 85% (r = 0.88), those with oxygen saturation ranging from 85% to 95% (r = 0.87), and also in preterm and term infants (gestational age < 28, 28−34, 34−36, and ≥ 37 weeks, r = 0.87, 0.92, 0.89, and 0.90, respectively). There were strong accuracy measures of the OI for OI cutoffs of 5, 10, 15, and 20 (area under the curve > 0.85). The equation relating the OI and OSI was represented by: OI = (2.3 × OSI) – 4. Conclusions: The OSI has a strong correlation with the OI, is a reliable assessor of the severity of respiratory failure in neonates without arterial sampling, and has high accuracy when the OI < 40.

Application of X-ray Diffraction (XRD) and Rock–Eval Analysis for the Evaluation of Middle Eastern Petroleum Source Rock

In this study, collected samples of nine different wells from the Middle East are used for various geochemical analyses to determine the hydrocarbon generation potential. The determination is carried out following the grain density, specific surface area, XRD, and Rock–Eval pyrolysis analyses. Four different types of kerogen are plotted based on the Rock–Eval analysis result. Kerogen type I usually has high hydrogen index (e.g., HI > 700) and low oxygen index, which is considered oil-bearing. Kerogen Type II has hydrogen index between type I and type II and oxygen index higher than type I (e.g., 350 < HI < 700) and is also considered to have oil-bearing potential. Kerogen type III has a lower hydrogen index (e.g., HI < 350) and is considered to have a primarily gas-generating potential with terrigenous organic matter origination. Kerogen type IV has a very low hydrogen index and higher oxygen index (compared with other types of kerogen), which is considered the inert organic matter. The kerogen quality of the analyzed samples can be considered as very good to fair; the TOC content ranges from 1.64 to 8.37 wt% with most of them containing between 2 and 4 wt%. The grain density of these examined samples is in the range of 2.3–2.63 g/cc. The TOC and density of the samples have an inversely proportional relationship whereas the TOC and the specific surface area (BET) has a positive correlation. The specific surface area (BET) of the examined samples is in the range of 1.97 m2/g–9.94 m2/g. The examined samples are dominated by clay, primarily kaolinite and muscovite. Additionally, few samples have a higher proportion of quartz and calcite. The examined samples from the Middle East contain kerogen type III and IV. Only two samples (JF2-760 and SQ1-1340) contain type I and type II kerogen. Considering Tmax and Hydrogen Index (HI), all of the samples are considered immature to early mature. Rock–Eval (S2) and TOC plotting indicate that most of the samples have very poor source rock potential only with an exception of one (JF2-760), which has a fair-to-good source rock potential.