Lanthanum histidine with pentaerythritol and zinc stearate as thermal stabilizers for poly(vinyl chloride)

Lanthanum histidine [La(His)(2) center dot (NO3) center dot 2H(2)O or La(His)(2)] was synthesized via the reaction of histidine and lanthanum nitrate, and it was investigated as a stabilizer for poly(vinyl chloride) (PVC). The results show that La(His)(2) exhibited a stabilizing effect on PVC as a long-term stabilizer because it prolonged the stability time of PVC to 76 min, which was about 24 times longer than the stability time of the pure PVC. The stabilizing effect of La(His)(2) as a costabilizer with pentaerythritol (Pe) and zinc stearate (ZnSt(2)) was also studied. The results show that the use of La(His)(2) with Pe or Pe/ZnSt(2) improved the stability time of PVC. La(His)(2)/Pe/ZnSt(2) provided PVC with a good initial color and long-term stability, and when it was prepared at mass ratios of 0.8: 2.4: 0.8 and 1.6: 1.6: 0.8, the stability times of PVC were improved to 86 and 88 min, respectively. As a nontoxic stabilizer, La(His)(2)/Pe/ZnSt(2) has the potential to replace the toxic stabilizers widely used in PVC manufacturing. (C) 2015 Wiley Periodicals, Inc.