Study On Alkali Type Lanthanum Citrate As A Heat Stabilizer Of PVC

In this paper alkali type lanthanum citrate was synthesized by citric acid、 sodiumhydroxide and lanthanum nitrate.And products was characterized by elemental analysis、infrared spectroscopy and thermogravimetric.and it was used as heat stabilizer of PVC totest effect by Congo red test、discoloration test and thermogravimetric analysis.Its heatstabilizer effect was contrasted with lead stearate、 zinc stearate、 calcium stearate、pentaerythritol and lanthanum stearate.results showed that the heat stabilizer effect ofalkali type lanthanum citrate on PVC is better than ole relative better others, but earlyanti-discoloration of alkali type lanthanum citrate is no good.Experiments proved that alkali type lanthanum can improve the heat stability of PVC,primarily through the hydroxyl who join with lanthanum ion and lanthanum ion absorbHCl of PVC degradation product,thus prevent PVC from autocatalysis,reach for inhibitionof degradation of PVC.Infrared analysis showed that lanthanum ions of t alkali typelanthanum can combine combine Cl of PVC to formation chemical bond of La-Cl.Because anti-tarnishing enhancement of single alkali type lanthanum on PVC is notobvious, so zinc stearate、calcium stearate、pentaerythritol and lanthanum stearate and othertraditional stabilizer were compound with alkali type lanthanum. Results showed thatanti-tarnishing capacity of composite stabilizer of alkali type lanthanum and zinc stearateon PVChas been significantly improved, but "burned zinc" is inevitable, the best ratio ofthis composite stabilizer is3/2.The effect of composite stabilizer of alkali type lanthanumand zinc stearate is better than single alkali type lanthanum on PVC thermal stability.bothThermal Stability Time and anti-tarnishing were improved.the best ratio of alkali typelanthanum/calcium stearate is2/3.The anti-tarnishing abilities of composite stabilizer ofalkali type lanthanum and Pentaerythritol on PVC have greatly improved, the best ratio ofthis composite stabilizer is3/2.three-component stabilizer including alkali type lanthanum、Pentaerythritol and zinc stearate.this stabilizer have a good show,whether Thermal StabilityTime or anti-tarnishing all have good effect.the best the best ratio of this composite stabilizer is4/2/4.the Comprehensive Capacity of this stabilizer is better than Lead stearate.Alkali type citric acid la, and quarter e four alcohol, and stearic acid zinc composition ofthree component composite hot stable agent, not only in hot stable time Shang also is inanti-discoloration Shang, regardless of is in early anti-discoloration situation also islong-term anti-discoloration situation, are has has very big of improved, best proportionsfor alkali type citric acid la/stearic acid zinc/quarter e four alcohol is4/2/4, and integratedcan over has stearic acid lead.Torque rheological experiments is Dynamic thermal stability test on thermal stability ofPVC. Results showed that Plasticizing capacity of PVC was promoted by alkali typelanthanum.when alkali type lanthanum as a stabilizer.all of Plastify time、plastify torqueand balance torque were lessen. alkali type lanthanum have plastication for PVC.