Study On Preparation Of Nanometer Lead Thermal Stabilizer

Lead hydrogen phosphite superfine powder, lead oxide phosphite hydrate superfine powder and tribasic lead sulfate superfine powder were prepared by micro-liquid-phase synthesis method (MLPS method) in this paper. At room temperature, acetic acid worked as catalyst, lead oxide and phosphite or sulfate were blended thoroughly, then were ground for tens minutes. The needed products were obtained. The product composition was determined by classic titration methods. The results showed that the contents were accorded with the standards of National Chemical Industry Department (HG2339-92 and HG2340-92). The products were characterized by XRD. Their XRD spectrums indicated that they were pure PbHPO3 ,2PbO·PbHPO3·0.5H2O and 3PbO·PbSO4·H2O. The size distribution and appearance of superfine particles were investigated by TEM, it showed the PbHPO3 particles were spherical or ellipsoidal, the size ranged from 30 nm to 60nm. The lead oxide phosphite particles were bar like, their size distributions were 20-50nm wide and 50-200nm long. The particle morphology of tribasic lead sulfate was not regular, the size was about l00nm. Congo-red method was used to determine the thermal stabilization ability of products, which were consisted of dibasic lead phosphite and tribasic lead sulfate. The results showed that the nanometer stabilizer obviously increased the ability of thermal stabilization. In the same thermal stability level it could cut 25%-33% amount of lead salt than using ordinary products. Some problemswere discussed in adding the nanometer additives into PVC resin.TEM was used to consecutively investigate the size and appearance of dibasic lead phosphite in the reaction process. It found that nanocrystal grain of lead oxide phosphite hydrate had favorite direction in the MLPS method, many nanocrystal grain in near area would aggregate and assembled as nanowire, The diameter of the nanowire was about a crystal grain size and the length of nanowire could reach hundreds of nanometers, then they would gather to needle or bar like particles. Thesize control of bar particles could be achieved by adding surfactant. The principle of MLPS and influence factors were discussed in the last, main influence factors were pointed out. The MLPS method was simple process, it could react in room temperature. The method was very suitable for industrial production of superfine powder.