Evaluation of the thermal stabilization behavior of hydrotalcite against organic stabilizers for plasticized PVC films

Clay-reinforced PVC composites and nanocomposites

Clay-reinforced polyvinyl chloride (PVC) composites and nanocomposites are one of the newest and most important compounds studied and used in various applications, including the biomedical, automotive industry, water treatment, packaging, fire retarding, and construction. The most important clays used in the synthesis of these composites are Bentonite, Montmorillonite, Kaolinite, and Illite. The addition of these nanoclays to the PVC matrix improves mechanical properties, thermal stability, and yellowness index properties. In this chapter, a detailed study of PVC and its properties, types of nanoclays and their properties, modification of nanoclays, production methods of composites, and nanocomposites of PVC/clay, their characterization, and applications have been performed. Herein, the types, properties, and applications of PVC/clay nanocomposites, as well as their challenges and future remarks, are reviewed.

Analysis of thermally and UV-Vis aged plasticized PVC using UV-Vis, ATR-FTIR and Raman spectroscopy

The stability of plasticized poly (vinyl chloride) (PVC-P) stored under indoor conditions, despite it being in commercial use for more than 80 years, hasn't been sufficiently experimentally examined, as documented in available works on PVC-P stability. With the increasing number of actively deteriorating priceless modern and contemporary artworks made of PVC-P, there is a growing need for studies dealing with the analysis of changing characteristics of PVC-P during its aging under indoor conditions. This work addresses these issues by designing PVC-P formulations, drawing on the available information on technology of PVC production and PVC compounding from the last century, and analyzing the changes in the characteristic properties of model samples made from the designed PVC-P formulations exposed to accelerated UV-Vis and thermal aging using UV-Vis, ATR-FTIR and Raman spectroscopy. The results of our study further expand the knowledge regarding the stability of PVC-P and the benefits of using non-destructive, non-invasive spectroscopic methods of analysis for monitoring changes in PVC-P characteristic properties induced by aging.

Bean Dreg-Hydrocalumite Composite as a Highly Efficient Thermal Stabilizer for Poly(vinyl chloride)

Bean dreg (BD)-hydrocalumite composites were prepared by a hydrothermal method with BD, Ca(OH)₂, Al(OH)₃, and Na₂CO₃ as raw materials. The samples were characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and N₂ physical adsorption-desorption. Their properties as a thermal stabilizer for poly(vinyl chloride) were tested using a torque rheometer and static thermal aging method. Compared with traditional hydrocalumite, the crystal size of the BD-hydrocalumite composite was relatively small, which made it exhibit good dispersion and better thermal stability for poly(vinyl chloride). In addition, the effects of preparation conditions on the properties of BD-hydrocalumite as a heat stabilizer were also investigated. Under the conditions of n[Ca(OH)₂/Al(OH)₃/Na₂CO₃] = 4.4:2:1, a BD dosage of 5%, a crystallization temperature of 90 °C, and 19 h, the prepared BD-hydrocalumite showed the best performance, and the dynamic thermal stability time of poly(vinyl chloride) reached 2149 s.

Chloride Removal of Calcium Aluminate-Layered Double Hydroxide Phases: A Review

Chlorine is a critical element with respect to the use of fossil fuel, recycling of industrial wastes, and water purification. Chlorine could form toxic chemical compounds, corrode pipe systems and boilers, and contaminate surface and ground waters. Calcium aluminate-layered double hydroxides are one of the most promising materials to remove chlorides due to the chemisorption mechanism, since the phases have positively charged interlayers. Many studies on the synthesis and the characterization of calcium aluminate-layered double hydroxides have been extensively conducted, whereas few studies have been conducted on the chloride removal characteristics of the phases. The state-of-the-art studies on the synthesis methods and the structural characteristics of CaAl-LDH phases, the underlying mechanism on the removal of chlorides, and the potential removal rate and the capacity in the present study were thoroughly reviewed.

Preparation of Magnesium-Aluminum Hydrotalcite by Mechanochemical Method and Its Application as Heat Stabilizer in poly(vinyl chloride)

The traditional methods for preparing magnesium aluminum layered double hydrotalcite (Mg₂Al-CO₃LDHs) in industry include coprecipitation and hydrothermal methods. Both these methods have the disadvantages of high preparation cost and complicated water washing process. Using Mg(OH)₂, Al(OH)₃, and CO₂ as raw materials in this work, the Mg₂Al-CO₃ LDHs are successfully prepared by mechanochemical method, which solves the shortcomings of traditional preparation method and realizes the conversion and utilization of CO₂ resource. The prepared Mg₂Al-CO₃ LDHs are evaluated as a heat stabilizer in poly(vinyl chloride) (PVC). The result indicates that, when 2.4 phr Mg₂Al-CO₃ LDHs, 0.3 phr ZnSt₂, and 0.3 phr of zinc acetylacetonate are added to the PVC, the thermal stability time of PVC can reach 190 min, which is better than PVC containing commercial Mg₂Al-CO₃ LDHs. Meanwhile, its processing performance is basically the same as the PVC containing commercial Mg₂Al-CO₃ LDHs.