Synthesis Of Zinc Borate/Reduction Graphene Oxide Hybrid Material And Its Flame Retardant Application On PVC

As one of the largest plastic production in the world,Polyvinyl chloride(PVC)usually need to add plasticizer to improve its plasticity,leading to decreased flame retardancy and the limited oxygen index(LOI)is less than 21%.Moreover,its poor thermal stability results in the release of HCl,CO and other low molecular compounds when heating,and also produces black smoke and corrosive gases.Currently,inorganic flame retardants are generally applied to PVC to delay the combustion,including metal oxides,metal hydroxides,antimony-based,boron-based and carbon-based materials,etc.Therefore,zinc borate(4Zn O·B2O3·H2O)/ reduced graphene oxide hybrid materials(ZB/RGO)were synthesized and applied to PVC with MH in this work.Then the flame retardant and smoke suppression performance of the corresponding samples were studied by LOI,microscale combustion colorimeter(MCC),cone calorimeter test(CCT).Afterwords,the ZB/RGO hybrid materials were modified by ionic liquids(IL),and the properties of PVC composites were studied in the same way,especially the mechanical properties and the antistatic properties.The details were as follows:Fristly,The ZB/RGO hybrid materials were synthesized by hydrothermal method and characterized by X-ray diffraction(XRD),fourier transform infrared(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),thermogravimetric analysis(TGA).The content of each component of hybrid materials were calculated by titration analysis.The results showed that the target production(ZB/RGO)was successfully synthesized by hydrothermal method.The ZB was 4ZnO·B2O3·H2O nanorods with uniform distribution,which is 150~350 nm in width,50~120 nm in thickness.And the content of RGO is 7.31% in the hybrid material.Secondly,the best formulation(2 phr ZB and 13 phr MH)that ZB and MH were cooperatively applied to PVC was studied through LOI,and then the same phr of ZB/RGO hybrid materials replaced the ZB in the best formulation.The flame retardant and smoke suppression performance research of the corresponding samples were investigated by means of MCC and CCT.The thermal degradation of PVC samples was studied by TG-DTG,and the residual carbon was analyzed by SEM and energy dispersive spectrometer(EDS).It was found that the LOI of PVC/2ZB/13 MH was 32.0%,which was the highest in all samples.PVC/2ZB/RGO/13 MH was 29.4%,which was 4.9% higher than that of pure PVC,and had a best effect on heat insulation and smoke suppression,especially that PHRR was 225 kW·m-2,TTI was 21 s,TPR was 26.19 m2·kg-1.Meanwhile,the effects of the added flame retardants on the mechanical properties and antistatic properties of PVC were studied.Compared to the pure PVC(395%),the addition of 15 phr ZB(252%)and 15 phr MH(210%)on the elongation at break were decreased by 36.08% and 46.9%,respectively.The elongation at break of PVC/2ZB/13 MH was the highest at 306%,while the elongation at break of PVC/2ZB/RGO/13 MH was reduced to 258%,which was still more than that of 15 phr ZB and 15 phr MH.On the other hand,the addition of flame retardants in the PVC samples had a little effect on the antistatic properties that the surface resistivity and volume resistivity were all 1014~1015 ?,which could be used as wire and cable.Thirdly,ZB/RGO hybrid materials were modified by imidazole ionic liquids in different proportions,and the properties of the composites were studied by the same method in the second part.The mechanical properties and antistatic properties of the composites were discussed emphatically.With the increase of the amount of ionic liquids,the LOI value was gradually decreased,elongation at break was increased firstily and then decreased,and the surface resistivity and volume resistivity gradually decreased while the decreasing trend gradually reduced.When mass ratio of the IL? ZB/RGO was 1 ? 1,the LOI of the composites was 28.5%,the elongation at break was highest at 374%,which was close to pure PVC(395%).The surface resistivity and volume resistivity were 3.3×1011 ? and 45.7×1011 ?·m,which could satisfy the requirements of the general anti-static of PVC.In flame-retardant aspect,the LOI became lower slightly.However,in the CCT,PVC/2IL-2ZB/RGO/13 MH composite material significantly reduced in the heat release and smoke preduce.