Application of two magnesium salt compounds in modified PVC energy cabless
Two types of magnesium based inorganic mineral powders are green and environment-friendly natural products,which can complement each other's advantages in terms of thermal stability and smoke suppression performance,achieving a wider and larger range.High mesh brucite powder(MH)and different meshes of hydromagnesite powder(HM)were prepared by physical grinding.The combustion performance,smoke density,mechanical properties and thermal properties of the modified polyvinyl chlo-ride(PVC)cable material were tested by using limiting oxygen index meter,smoke density test box,universal mechanical testing machine and thermogravimetric analyzer,and the final combustion carbon residue was tested in detail by using Raman spectrometer,scanning electron microscope and energy dispersive spectrometer.The results show that high mesh MH mixes with high mesh HM can improve the flame retardancy of PVC composites to a certain extent,especially the maximum smoke density and smoke density grade decreases by 33.6%and 42.9%respectively.At the same time,it can effectively improve the thermal stability of modified PVC cable materials,as evidences by an increase of 5.3%and 56.5%in the initial degradation temperature and pyrolysis tempera-ture at 50%,respectively.The residual carbon rate can be significantly increased after combustion,which have increased by 3.6 times and 4.3 times at 600℃and 800℃,respectively.The addition of MH combined with high mesh HM can also effectively improve the degree of orderliness of residual carbon,making it more dense and continuous,the transitivity of heat,mass,and airflow can be inhibited.Especially,the agglomeration of MgO on the surface of residual carbon can be promoted,which can effectively improve the physical barrier effect.Finally,the physical method for preparing high mesh magnesium-based powders is inexpensive and has lower comprehensive application costs.
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