PVC heat stabilizers thermal stabilizing effect of the conductivity measurement method

PVC heat stabilizer effect of thermal stability measuring method, also known as electrical conductivity potential method. Experimental apparatus composed of four main parts, an inert gas means the right, the general use of nitrogen, but sometimes the use of air, the  Metal stearate difference is that when using nitrogen protected, the oxygen in the air to avoid oxidation of PVC degradation arising parent chain. Experimental heating apparatus is generally of about 180 ℃ oil bath pot, inside the pot into the oil bath and with PVC heat stabilizer mixture, when HCl gas is generated, will be left with the inert gas into the NaOH solution in, NaOH rapidly absorbed HCl, resulting pH of the solution changes with time by recording the  Plastic impact modifier change in pH meter can determine the type of the effect of heat stabilizers. The experimental results, the process pH-t curve obtained into induction and growth period, the length of the induction period with the effect of heat stabilizer different merits. One-step co-precipitation method were synthesized containing stearate, dodecyl benzene sulfonate hydrotalcite.
(L) material: MgNO3, AINo3, NaoH, Naeo3, sodium lauryl sulfate, stearic acid
(2) reaction step: 1000ml beaker in a certain amount of deionized water while a solution concentration of 0.85mol / L, o.4mol / L of magnesium nitrate and aluminum nitrate solution, to which a certain amount of NaCO3 solution, adding NaOH solution to the PH value of the magnesium stearate  reaction solution was maintained at around 10, the synthesis temperature 45 ℃, sodium lauryl sulfate were added last, stearic acid, after precipitation of different synthetic hydrotalcite, after filtration, washing and drying, the final solution containing different hydrophobic anionic hydrotalcite.