Abstract: <P><SPAN lang=EN-US>Surface modification of magnesium hydroxide by silane coupling agent (KH-550 and KH-560) and stearic acid was investigated.By comparing the transmissivity of the above modified samples in liquid paraffin,results were obtained that stearic acid was the most excellent modifier.And the optimal process conditions were as follows:dosage of stearic acid was 6% [as the mass of dry Mg(OH)</SPAN><SPAN lang=EN-US><SUB>2</SUB> powder],modified temperature was <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:chmetcnv w:st="on" UnitName="℃" SourceValue="80" HasSpace="True" Negative="False" NumberType="1" TCSC="0">80 <SPAN lang=EN-US style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman""><SPAN lang=EN-US>℃</SPAN></SPAN></st1:chmetcnv>,and modified time was 60 min.XRD,FT-IR,and TG-DSC were used to characterize the modified samples,and the analyzed results indicated the mechanism of surface modification was that stearic acid was attached to the surface of magnesium hydroxide by hydrogen bond formed between stearic acid molecule and hydroxide radical of magnesium hydroxide,so the interconsistency between magnesium hydroxide and polymer got improved.</SPAN></P> <P><SPAN lang=EN-US></SPAN>&nbsp;</P>