Study On Structure And Properties Of Flame Retardant ABS

The thesis was composed of three parts including the studies on the stability of CPE, the development of flame retarding ABS with and without halogen fire retardant. The emphasis was given to study on the structure and properties of flame retardant ABS. The mechanism of flame retarding of various flame retardant was also discussed.Experiments of Congo Red showed that there was good stability for CPE with the combine of hydrotalcite and dibutyltin dilaurate.After added DBDPE/Sb₂O₃ ,the property of flame retarding of ABS compounds increased dramatically, but the impact strength decreased. The compounds met the requirement of UL94 V-0 with the retardant content 14wt%,while the impact strength decreased from 130J/m of neat ABS to about 35J/m. It is a decrease of 73.1%. DBDPE/Sb₂O₃ belongs to typical mechanism of gas phase flame retarding.After added CPE , the impact strength of ABS composites dramatically increased. It increases from 130J/m of neat ABS to about 230J/m, which has a increase of 76.9%. SEM shows that the spherical structure of disperse phase in the section of CPE/ABS blends is elongated. It has a elongation of more than 100%. When the material is elongated, CPE particles are pressed at the position of equator and consequently have a elongation, which can absorb more energy. As a result, the toughness of the blends is improved.Experiments showed that there is a synergic effect between the covering red phosphorus(CRP) and MCA. The ABS compounds can meet the requirement of UL94 V-0 with the retardant content 20wt%. CRP/MCA was also a good smoke retardant for ABS.There is a big different between sample residuals after combustion. There was nothing on the aluminum sheet after compounds ABS/DBDPE/Sb₂O₃, ABS/phosphorus-based flame retardant, and ABS/MCA were combusted, which showed that they mainly played flame retarding role in gas phase. There were thick and continuous chars on the aluminum sheet after compounds ABS/ CRP, ABS/aluminium hydroxide, and ABS/ magnesium hydroxide were combusted, and chars were more compact with flame retardant increasing, which showed that they mainly played flame retarding role in solid phase.