The Facile Strategy of Improving the Long-Term Stability of Highly Transparent Polyvinyl Chloride by Introducing Unsaturated Zn Oleate and Uracil Derivatives

Abstract

In order to improve the initial color and the long-term heat stability of super-transparent polyvinyl chloride (PVC), a series of composite heat stabilizers consisting of unsaturated Zn oleate and uracil derivatives have been designed in this paper. The uracil derivatives are 1,3-dimethyl-6-amino-uracil (DAU) and 6,6′-diamino-1,1′,3,3′-tetramethyl-5,5′-(ethylidene)bisuracil (OSU). The static thermal stability, dynamic thermal stability, and transparency were used to evaluate the properties of the stabilized transparent PVC sheets. The results indicate that the compatibility between the stabilizer and PVC was greatly enhanced by introducing an unsaturated long-chain Zn oleate and a long alkyl chain bisuracil derivative. Through the thermal discoloration test, the best ratio of DAU/zinc oleate (DAU/Zn) and OSU/zinc oleate (OSU/Zn) was determined to be 4:1, with a total amount of 3 phr in 100 phr PVC. It was verified that the combination of zinc oleate with uracil derivatives could improve the long-term thermal stability of PVC, and the DAU/Zn was better than that of the OSU/Zn. In addition, through the transmission/haze verification, adding a proper amount of epoxidized soybean oil (ESBO) and phosphite ester to the OSU/Zn system has a certain synergistic effect. The thermal stability and transparency of PVC can be remarkably enhanced.

Preparation and performance of PVC long‐term heat stabilizer based on the synergistic effect of uracil and metal complexes

“…Better transparency can greatly broaden the application range of PVC. [1,25] The SEM of the cross-section of PVC sheets with DAU and DAJ is shown in Figure 7. All cross-sectional morphology has similarities.…”

“…According to the static and dynamic thermal stability experiments and previous reports, the thermal stability mechanism of the DAJ system for PVC was proposed. [1,16] First, DAU replaced the active Cl, which reduced the conjugated polyenes structure and improved the initial coloring. Simultaneously, [Zn(ttr)(OAc)] absorbed the HCl released from the PVC chain and produced amitrole and some Lewis acid ZnCl 2 which accelerated PVC aging.…”

“…As one of the first industrialized plastic products globally, polyvinyl chloride (PVC) has excellent wear resistance, corrosion resistance, and flame retardancy. [ 1 ] However, PVC's poor thermal stability implies that it deteriorates at processing temperatures, resulting in product discolouration and performance loss. [ 2 ] At present, among the ways to solve this problem, adding heat stabilizer in PVC processing is an economical and effective method.…”

“…[10] Due to its excellent thermal stability and non-pollution, more research and studies are now focusing on organic nitrogen-containing heat stabilizers. [1,11] Among them, 1,3-dimethyl-6-aminouracil (DAU) has a particular thermal stability and biocompatibility, but due to its poor compatibility with PVC, its long-term stability, weak transparency, and poor initial coloring need to be further improved. [12,13] Ye et al reported the excellent thermal stability and processing properties of 5,6-diamino-1,3-dimethyluracil, revealing that the role of uracil may mainly depend on the mechanism of HCl adsorption and chemical bonding.…”

Thermal stabilization of polyvinyl chloride by calcium and zinc carboxylates derived from byproduct of palm oil refining

“…Tin-based organic compounds and mixed metal carboxylates are alternatives to lead salts. Organic tin groups are known to be effective, but they are expensive ( Song et al., 2022 ). Mixed metal thermal stabilizers are popularly used due to their advantages of being non-toxic and low price ( Ye et al., 2019 ).…”