Study on lanthanum-pentaerythritol alkoxide as a thermal stabilizer for rigid polyvinyl chloride

Abstract

Lanthanum‐pentaerythritol (La‐PE) alkoxide, a polyol‐based metal alkoxide, had been synthesized and used as a thermal stabilizer for polyvinylchloride (PVC). Thermogravimetric (TG), differential thermal analysis (DTG), mass spectrum (MS), and Fourier transform infrared (FTIR) spectroscopy were used to confirm the synthesis reaction. The thermal stability of rigid PVC stabilized with La‐PE was tested by means of the Congo Red test, conductivity test, thermal aging test, thermal gravimetric analysis (TGA), and UV‐visible (UV‐vis) spectroscopy. The results showed that addition of La‐PE could significantly prolong static stability time of PVC and increase the apparent activation energy for degradation reaction. The oven aging test showed that La‐PE could improve the initial color of PVC. Moreover, addition of La‐PE could significantly reduce the concentrations of the conjugated double bonds of PVC and reduce weight loss. The possible thermal stability mechanism had also been discussed. Besides having good ability to neutralize hydrochloric acid (HCl), La‐PE could substitute or inactivate the labile chlorine atoms in the PVC chains. J. VINYL ADDIT. TECHNOL., 23:55–61, 2017. © 2015 Society of Plastics Engineers

Investigation of lanthanum trioxypurine with zinc stearate and pentaerythritol as complex thermal stabilizers for poly(vinyl chloride)

“…It is generally accepted that the aging and discoloration of PVC strips are the primary defects to limit the application of PVC, and the main cause of this phenomenon is the dehydrochlorination reaction with progressively increasing numbers of conjugated double bond on the main chain of PVC in the process of aging . Some researches show that the concentration of conjugated double bond has showed certain connection with the UV–visible absorption wavelength, and the maximum absorption wavelength is intensively depends on unsaturated sequence (n).…”

“…Some researches show that the concentration of conjugated double bond has showed certain connection with the UV–visible absorption wavelength, and the maximum absorption wavelength is intensively depends on unsaturated sequence (n). The UV–visible absorption wavelength will gradually increase to the visible area with increase of the aging degree . Therefore, it can be considered that the greater absorption wavelength of visible light shows the higher concentration of conjugate double bonds.…”

“…Zhang et al designed and synthesized a lanthanum‐pentaerythritol alkoxide (La‐Pe) by the traditional preparation method. The results showed that PVC stabilized with La‐PE had good initial color and long‐term stability, which could be attributed to the strong coordination of La atoms in La‐Pe with active chloride atoms in PVC and the strong ability to neutralize HCl . Li et al designed and synthesized a lanthanum histidine complex and investigated as a stabilizer for PVC.…”

“…Among the rare earth stabilizers, organic lanthanum complex stabilizers show higher thermal stability for PVC . Recently, many researchers have taken plenty of time to synthesize lanthanum stabilizers and investigate their thermal stability for PVC . Li et al successfully prepared a basic complex (LaL) by a precipitation method in aqueous solution and used as a stabilizer for PVC.…”

Tensile properties, thermal stability, and the mechanism of PVC stabilized with zinc and calcium oxolinic complexes

“…At the same time, some new types of complexes with different cations were also prepared and used as thermal stabilizers for PVC. Most cations belong to rare earth elements, such as lanthanum, yttrium, and so on. However, the category of non‐poisonous cations is smaller than the available non‐poisonous anions, which could be used as thermal stabilizers for PVC.…”