Preparation Of Brominated Anhydride Flame Retardant And Study On The Flame Retardant Finishing Of Polyester/Cotton Fabric

PET/cotton blended fabric plays an important role on textile clothing anddecoration materials. Thus, the flame retardant of it has been treated more andmore strictly. The flame retardant finishing of PET/cotton blend fabric is moredifficult because of the different properties of cotton and polyester fibers, as wellas the ‘‘scaffolding effect’’ of the blend and wash fastness required foracceptable flame retardancy. Although many researches about this have beendone, so far, there wasn’t been developed a durable flame retardant of PET/cottonfabric.The decomposition temperature of BFR was about200-300℃normally,which matches that of various polymers. So BFR can stop burning in the gasphase or the condense phase at the right temperature. The flame retardantefficiency of BFR is greatly improved when used together with the synergisticagent such as Sb2O3. Although “dioxin” problem of polybromodiphenyl ethers made it be challenged, brominated flame retardant will keep its leading positionin FRs because of its high flame retardant efficiency and the less impact to themechanical properties of composite materials.Brominated anhydride flame retardant is a kind of reactive flame retardantand one of the most commonly used is tetrabromophthalic anhydride. This kindof flame retardant is often used for the flame retardant of polymer because of thereactive group such as hydroxyl and carboxyl, which could polycondensationwith the monomer substance of the polymer or directly graft in the polymer chain.Although the flame retardant is efficient, the widely using is also limited by thehigh prices. In this paper a novel aliphatic BFR was synthesized which can givethe PET/cotton fabric good flame retardant properties. The new flame retardantcan reduce the release of toxic products during combustion, thus it is a promisingresearch direction to impart PET/cotton fabric durable flame retardantperformance.Firstly,2,3-dibromo-succinic anhydride (DBSA) was synthesized via theaddition reaction of maleic anhydride and bromine in ethyl acetate solution. Inthis paper, the synthesis process was optimized, when maleic anhydride is0.1mol, ethyl acetate is40mL, the molar ratio of maleic anhydride and bromide is1:1.2, tempreture is50℃and time is5hours, under these conditions can getgood results. But the yields keep at around50%, in order to improving theproductivity further, dimethyl benzene/water mixture was used as an anti-solventwhich can effectively reduce the solubility of the target product in the originalsolute and made the product deposit from the solution easily. This method canimprove the product purity and increase the yield to above85%. The synthesiedcompounds were characterized by using IR, elemental analysis, DSC methods.The results of infrared spectra and the elemental analysis were consistent with target product. The compound melting point is167-169℃, and be close to thetheoretical value of169-170℃. It can be seen from the TGA and DTG curves ofDBSA, the decomposition of DBSA was started at170℃and the maxmumouccur after200℃.The application and the flame retardancy of DBSA on cotton, PET asnPET/cotton were studied. DBSA was applied to cotton and polyester/cottonfabrics though the pad drying method for the first time. The infrared analysis oftreated fabric showed that the cotton fibers were bonded with the DBSA by esterbond through the esterification reaction. The amount of free carboxyl group in thefabric was measured by titration of calcium acetate. The optimum finishingprocess was determined by experiments and the LOI value was increased from17.0to27.8, the length of the vertical burning damaged10.9cm and rate of thegrafting reaction between DBSA and cellulose was48%at this condition. TheLOI value was25.2after washed12times. The experimental results showed thatDBSA has better application performance in the polyester/cotton fabric. The hightemperature and hight pressure method, thermosol method and carrier methodwere used for PET treated with DBSA respectively. Compared with hightemperature and hight pressure method and thermosol method, carrier method canincrease the chance of flame retardants into the fiber to give better flameretardant properties. However because of the flame retardant is water-soluble, sothe flame retardancy of treated polyester is not obvious.In order to improve the flame retardant properties of DBSA in PET/cottonfabric, synergist was used with DBSA. Antimony oxide is good synergist withbromine, but because of the antimony oxide does not dissolve in water; itsapplication in textiles is limited. The preparation technology of colloidalantimony pentoxide is a hot topic recent years. Flame Retardant finishing effect of colloidal antimony pentoxide used on fabric is also significant. This paperprepared Sb2O5hydrosol with high stability by reflux oxidation and determinedthe best reflux conditions. Due to the synergistic effect of Sb2O5hydrosol, theLOI value of PET/cotton fabric can be up to35or more using Sb2O5hydrosol andDBSA by two-step finishing. After finishing, damage length is10cm or less,fire-retardant effect is obvious. The Sb2O5hydrosol adding enhanced flameretardant effect of DBSA. The experimental results showd that when Br: Sb (mol)=3:1, the flame system can achieve the best synergistic flame retardant effect.CP is durable flame retardant for cotton and it belongs to the reactivephosphorus-nitrogen flame retardant. During the using of CP, the crosslink agentsare usually added as building bridge between flame retardants and fibers.Crosslink agents generally used N-Methylol compound which maybe release thefoemaldehyde during the production and using. Experiments explore the effectsof CP concentration on cotton fabric flame retardant finishing, and the reaultsshowed that the finished cotton fabric has better flame retardancy when theconcentration was35with the LOI value was28.7and damage length could bereduced to10cm or less. The phosphorus content was2.4%by fabric weight atthis time. But for PET/cotton fabric, the flame retardant effect is not obvious, andwhen the CP concentration was65%, the theoretical phosphorus content onPET/cotton fabric was4.4%meanwhile, the LOI value of treated PET/cottonfabric only reached27.4. The PET/cotton fabric treated with DBSA and CPwithout CHN was studied. The result showed when the flame retardants amountwas10%, CP amount was15%, the value of (LOI-∑LOIi) could be reach to4.0, while the DBSA amount was20%, CP amount was25%, the value of (LOI-∑LOIi) could be reach to3.1, and the LOI value was34.6, the char lengthwas4.6cm and there was no after flame and no after glow. The reaction between CP and DBSA was confirmed by measuring the amount of free carboxyl on fabric,and the water resistance of the treated fabrics is still need to improve.DBSA-Sb flame retardant system of the flame retardant was confired is thebest by comparing of the flame retardant effect DBSA, DBSA-Sb and DBSA-CPflame retardant systems on the PET/cotton blended fabric. The flame retardingeffect of DBSA is more significant and gives a new direction for the research anddevelopment of flame retardant finishing of polyester-cotton fabric.