A Vanillin-Derived,DOPO-Contained Bisphenol as a Reactive Flame Retardant for High-Performance Epoxy Thermosets

Quest for bio-based halogen-free green flame retardant has attracted many concerns in recent years.Herein a reactive functional flame retardant containing phosphorus VDP is synthesized from vanillin,9,10-dihydro-9-oxa-10-phosphophene-10-oxide(DOPO)and phenol via a facile way.VDP is characterized with^(1)H NMR,^(31)P NMR,FTIR and Time of Flight Mass Spectrometry,and used as a new reactive flame retardant for bisphenol epoxy thermosets.Thermogravimetry analysis shows that when the VDP loading is only 0.5P%(based on phosphorus content),the residue increases from 14.2%to 21.1%at 750℃ in N_(2)compare with neat DGEBA.Correspondingly,the limit oxygen index increased to 29.6%,and flame retardancy reaches UL-94 V0 grade.Micro combustion calorimetry(MCC)and cone calorimetry analyses demonstrate that VDP can significantly lower flammability of the epoxy thermoset.With only 0.5P%of VDP,the heat release rate,total heat release rate and smoke production are reduced markedly.At the same time,the mechanical properties of the modified epoxy thermosets are also improved.The impact strength increases by 34%and the flexural strength increased by 23%,with 1.5P%of VDP.In short,VDP not only improves the flame retardancy,but also improves the mechanical properties of the epoxy thermosets.

Borate-Modified,Flame-Retardant Paper Packaging Materials for Archive Conservation

Paper packaging materials like cardboards are widely used to protect archives which are a major kind of cultural relics.Unfortunately,paper is a combustible material,and thus exploring environment-friendly flame retardant for paper-based archive packaging material plays an important role.Herein,boric acid,borax and disodium octaborate are used to modify the craft paper-based packaging materials for archive conservation to improve fire safety.The modified craft paper exhibits much higher flame retardancy than the pristine one dose based on vertical burning tests,without much influence on mechanical properties such as tensile strength and elongation at break.Thermogravimetric analysis(TGA),scanning electron microscope(SEM),and X-ray photoelectron spectroscopy(XPS)reveal that porous glass structure is formed during the combustion,because thermal decomposition of boric acid,borax and disodium octaborate will produce porous glassy matter as B_(2)O_(3).The porous glass covers the paper surface as an insulating layer which retards the further pyrolysis and combustion,resulting in a denser carbon layer.Our study provides a robust way to reduce the fire hazard of the archive packaging material by applying environment-friendly boron-based fire retardants.

A New DOPO-Eugenol Adduct as an Effective Flame Retardant for Epoxy Thermosets with Improved Mechanical Properties

The development of efficient green flame retardants is an important way to realize more sustainable epoxy thermosets and downstream materials.In this work,a monoepoxide is synthesized through O-glycidylation of eugenol,and then reacted with DOPO(9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide)to obtain a new bio-based flame retardant,DOPO-GE.DOPO-GE is blended with a bisphenol A epoxy prepolymer exhibiting good compatibility and DDS(4,4′-diaminodiphenylsulfone)is used as the curing agent to afford epoxy thermosets.Although DOPO-GE leads to the reduced glass transition temperature of the thermosets,the storage modulus increases considerably.The DOPO-GE-modified thermosets exhibit the high thermal stability with the onset thermal decomposition temperature in nitrogen and air exceeding 300℃.When the phosphorus content in the thermoset is 1.0%,the residual yield of the thermosets at 750℃ in nitrogen increases from 13.9%to 30.6%,due to the increased charring ability.More interestingly,when the phosphorus content is only 0.5%,the limiting oxygen index is as high as 30.3%with UL94 V0 achieved.Cone calorimeter results reveals the significantly decreased heat release rate,total heat release,mass loss and total smoke production.Furthermore,DOPO-GE can notably improve the flexural strength,flexural modulus and fracture toughness,whereas the shear and impact strength are reduced to varied extents.In short,DOPO-GE can be obtained via a facile way,and shows the good flame-retardant effect on the epoxy thermosets with an application potential.

Catalytic oxidation effect of MnSO_(4) on As(Ⅲ) by air in alkaline solution

The catalytic oxidation effect of MnSO_(4)on As(Ⅲ) by air in an alkaline solution was investigated.According to the X-ray diffraction (XRD),scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analysis results of the product,it was shown that the introduction of MnSO_(4)in the form of solution would generate Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O with strong catalytic oxidation ability in the aerobic alkaline solution,whereas the catalytic effect of the other product MnOOH is not satisfactory.Under the optimal reaction conditions of temperature 90℃,As/Mn molar ratio 12.74:1,air flow rate1.0 L/min,and stirring speed 300 r/min,As(Ⅲ) can be completely oxidized after 2 hr reaction.The excellent catalytic oxidation ability of MnSO_(4)on As(Ⅲ) was mainly attributed to the indirect oxidation of As(Ⅲ) by the product Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O.This study shows a convenient and efficient process for the oxidation of As(Ⅲ) in alkali solutions,which has potential application value for the pre-oxidation of arsenic-containing solution or the detoxification of As(Ⅲ).

Ephedrine hydrochloride inhibits PGN-induced inflammatory responses by promoting IL-10 production and decreasing proinflammatory cytokine secretion via the PI3K/Akt/GSK3β pathway

Approaches for controlling inflammatory responses and reducing the mortality rate of septic patients remain clinically ineffective; new drugs need to be identified that can induce anti-inflammatory responses. Ephedrine hydrochloride （EH） is a compound that is widely used in cardiovascular diseases, especially to treat hypotension caused by either anesthesia or overdose of antihypertensive drugs. In this study, we reported that EH also plays an important role in the control of the inflammatory response. EH increased IL-IO and decreased proinflammatory cytokine （IL-6, tumor-necrosis factor （TNF）-a, IL-12 and IL-11~） expression in primary peritoneal macrophages and Raw264.7 cells treated with peptidoglycan （PGN）, a Gram-positive cell wall component. The anti-inflammatory role of EH was also demonstrated in an experimental mouse model of peritonitis induced by intraperitoneal PGN injection. The phosphatidylinositol 3-kinase （PI3K）/Akt pathway was found to be responsible for the EH-mediated increase in IL-IO production and decrease in IL-6 expression. Therefore, our results illustrated that EH can help maintain immune equilibrium and diminish host damage by balancing the production of pro- and anti-inflammatory cytokines after PGN challenge. EH may be a new potential anti-inflammatory drug that can be useful for treating severe invasive Gram-positive bacterial infection.