Preparation Of DOPO Derivative Flame Retardants And Their Applications

Poly?ethylene terephthalate??PET?is widely used for producing high performance engineering plastics,clothing and decorative materials due to its excellent mechanical performance,dimensional and chemical stability.The high flammability of PET restricts its applications which the flame retardancy was required.Phosphorus-containing flame retardants as one kind of the most effective alternatives have received a large number of studies with the trend to restrict using halogen-containing flame retardants.At the same time,improving the anti-dripping performance of PET is an important research direction.9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide?DOPO?as one kind of the phosphorus-containing flame retardants have received more and more attention.There are fame retardant PET commodities which used DOPO derivatives as commoner,but the researches about flame retardant finishing of PET fabric by DOPO derivatives are few.In this thesis,DOPO was as the starting flame retardant,it systematically carried out the research and development of its derivatives for flame retardant finishing of PET fabric,and flame retardant treatment of PET plastic was also given consideration.On the basis of the flame retardant effect investigation of DOPO flame retardant finish PET fabric.Then its derivatives were synthesized from the aspect of reducing the activity of P-H bond to improve the feasibility with disperse dyes in one bath and the utilization of flame retardants.On the other hand,in order to improve the flame retardancy of flame retardants and anti-dripping performance of PET fabric,DOPO was combined with the flame retardant groups which mainly act through the condensed phase.The mainly research work is as follows:?1?DOPO dispersion with the mean particle size of 1²?m was prepared which was used to finish PET fabric.As for the preparing of DOPO dispersion,the amount of DOPO,dispersant,disperse stabilizer were optimized to obtain the optimal dispersion preparing process.The prepared DOPO dispersion was applied onto PET fabric via exhaustion process or thermosol process by its own or together with disperse dyes and compared with the commercial bromine containing flame retardant DFR.The results revealed that flame retardancy of DOPO treated PET fabric was obviously improved which was almost similar to the flame retardant effect of DFR.The LOI of PET fabric which treated by DOPO via exhaustion or thermosol process reached about32%.The LOI of the treated PET fabric after 5 home laundering circles increased slightly which meant good laundering durability of these treatments.The flame retardancy of PET fabric which treated by DOPO dispersion and disperse dyes in one bath was obviously improved.While the dyeing performance of disperse dyes was influenced greater than DFR which maybe associated with the P-H bond in DOPO.The flame retardant mechanism was investigated by pyrolysis-gas chromatography/mass spectrometry?Py-GC/MS?analysis,FTIR analysis,scanning electron microscopy?SEM?and other methods.The flame retardant mechanism of DOPO finished PET fabric mainly act through gas phase,it didn't exist condensed phase action.While DFR possessed both gas phase and condensed phase action?But the condensed phase action of DFR wasn't mainly the char formation.effect?.?2?To avoid the influence of P-H bond to the disperse dyes,DOPO reacted with formaldehyde to synthesize its hydroxyl methylation derivative?DOPO-CH₂OH?.The results revealed that DOPO-CH₂OH could be used together with disperse dyes for flame retardant finishing and dyeing in one bath,but the flame retardancy was lower than that of DOPO.It related with the lower addition which maybe arise from the introducing of high polarity hydroxymethyl group.So the low polarity DOPO-CH₃ was synthesized.The flame retardancy of its treated PET fabric was better than that of DOPO-CH₂OH.The utilization of DOPO-CH₃ was 2.6 times of DOPO-CH₂OH under the same dosage and finishing condition,also higher than that of DOPO.Therefore,reducing the polarity was beneficial for improving the utilization of flame retardant in a certain case.The results of flame retardant mechanism investigation indicated that DOPO-CH₂OH and DOPO-CH₃ mainly act through gas phase action,without condensed phase action.?3?In order to improving flame retardancy and anti-dripping performance through promoting the char formation of PET,two novel DOPO containing flame retardants were synthesized.?1?DOPO was combined with cyclotriphosphazene which possess a certain char formation ability.Aflameretardanthexa-?phosphaphenanthrene-hydroxylmethyl?-cyclotriphosphazene?DOPO-TPN?which contained phosphaphenanthrene and cyclotriphosphazene was synthesized by DOPO-CH₂OH and hexachlorocyctriphosphazene.The onset decomposition temperature of DOPO-TPN was 50°C higher than DOPO-CH₂OH,it could be used as an additive for flame retardant blending with PET.The results revealed that DOPO-TPN endowed PET good flame retardancy with a low loading.The PET composite achieved a LOI of 34%when the loading was5 wt%,and its vertical burning test reached UL-94 V-0 rating.The flame retardancy of treated PET fabric was slightly better than that of the same dosage of DOPO-CH₂OH while lower than that of DOPO and DOPO-CH₃ by exhaustion process.The LOI of DOPO-TPN finished fabric by thermosol process was higher than the exhaustion process.The anti-dripping performance of PET fabric haven't been improved.It maybe relate to its large molecular volume which made it wasn't easily to enter into PET fiber.The flame retardant mechanism investigation revealed that DOPO-TPN which contain cyclotriphosphazene flame retarding PET polyester and fabric existed both gas phase and condensed phase action.?2?DOPO-CH₂OHwasreactedwiththerelativelysmallmolecularvolume2-chloro-5,5-dimethyl-2-oxide-1,3,2-dioxaphosphorinane?DOPC?tosynthesize2-phosphaphenanthrene-hydroxylmethyl-2-oxide-5,5-dimethyl-1,3,2-dioxaphosphorinane ?DOPO-DOPC?.The onset decomposition of DOPO-DOPC was also 50°C higher than DOPO-CH₂OH,so it could be used as an additive for flame retardant blending with PET.The results revealed that the PET composite achieved a LOI of 32.7%when phosphorus content was about 0.25%,and its vertical burning test reached UL-94 V-0 rating.PET polyester with a lower phosphorus content.which contained DOPO-DOPC achieved better flame retardancy than DOPO-TPN,so the flame retardancy DOPO-DOPC was better than DOPO-TPN.The flame retardancy of its treated PET fabric was much better than that of DOPO-CH₂OH,similar to that of DOPO and DOPO-CH₃.The anti-dripping performance of DOPO-DOPC finished PET fabric was also improved,and it also had good laundering durability.The investigation of flame retardant mechanism revealed that DOPO-DOPC flame retarding PET polyester and fabric act both gas phase and condensed phase action.And its condensed phase action was more obvious than DOPO-TPN.Comparing with DOPO and the other derivatives,DOPO-DOPC was more suitable for flame retardant finishing of PET fabric.Comparing DOPO and its derivatives with 5commercial PET fabric flame retardants,the flame retardant performance of DOPO and its derivatives was better,especially the better laundering durability.The utilization of DOPO and the above derivatives was much lower than the commercial flame retardants using exhaustion process.DOPO-DOPC possessed a certain anti-dripping performance to PET fabric,the utilization of it can reach 27%when treated PET fabric by thermosol process,both LOI and vertical burning performance of its treatment were excellent.It has comprehensive advantages compared with commercial flame retardants.Therefore,the approach of combination DOPO with carbon source to synthesize flame retardant is reasonable in this thesis.