Messi Biology states that Polyvinyl Chloride (PVC), as one of the world’s most produced general-purpose plastics, is widely used in pool liners, chemical piping, water treatment equipment, and medical consumables due to its low cost, excellent processability, and corrosion resistance. However, PVC is prone to aging and failure in chlorine-rich environments. Active chlorine found in chlorinated disinfectants, industrial wastewater, or seawater accelerates the degradation of PVC molecular chains, leading to brittleness, discoloration, and a sharp decline in mechanical properties. Magnesium carbonate, an eco-friendly inorganic material, is emerging as the key solution to PVC’s chlorine resistance challenges, safeguarding its stable application in chlorine environments.
The suitability of magnesium carbonate for PVC’s chlorine resistance stems from its unique physicochemical properties. It is a white crystalline powder with excellent dispersibility, thermal stability, and weak alkalinity. During the PVC processing stage, it blends uniformly with resins, plasticizers, and other components without compromising the material’s molding or basic performance. Most importantly, its weak alkalinity and chlorine-capturing capability provide precise protection against PVC’s specific vulnerabilities to chlorine.
In the production of PVC products, magnesium carbonate is primarily integrated through compounding. During manufacturing, magnesium carbonate powder is added at a ratio of 2%–6% along with PVC resin, plasticizers, and stabilizers into a mixer. After high-temperature melt-blending, the material is shaped via extrusion, injection molding, or calendering. When the finished PVC product encounters a chlorine environment, magnesium carbonate initiates “chemical protection”: its weak alkalinity neutralizes acidic substances generated by chlorine reactions, thereby inhibiting dehydrochlorination—the primary cause of PVC degradation in chlorine. Simultaneously, magnesium carbonate actively captures active chlorine radicals and converts them into stable chlorides, preventing chlorine molecules from attacking sensitive structures in the PVC molecular chain and delaying the aging process.
Beyond chemical protection, magnesium carbonate builds a “physical barrier.” Once uniformly dispersed within the PVC matrix, it fills the gaps between resin molecules, enhancing the material’s structural density and reducing the permeation rate of active chlorine. Furthermore, the high thermal stability of magnesium carbonate reduces the risk of thermal degradation during processing, further strengthening the overall stability of the product and forming a dual protection system of “chemical inhibition + physical blocking.”
Precise control of the dosage is crucial for guaranteed results: insufficient addition leads to inadequate protection, while an excess may affect the flexibility and processing fluidity of the PVC. PVC products modified with magnesium carbonate can see a 4–6 times improvement in chlorine resistance. Even after long-term immersion in chlorinated pool water or use in industrial chlorine media, these products maintain excellent toughness and structural integrity, with their service life extended by 2–3 times.
Today, as industries such as water treatment, chemical processing, and pool facilities upgrade their requirements for chlorine-resistant materials, magnesium carbonate has become the preferred choice for PVC modification due to its environmental friendliness, high efficiency, and controllable cost. This common inorganic compound not only overcomes the application bottlenecks of PVC in chlorine environments but also expands the boundaries of PVC applications, providing more reliable and durable material solutions for both industrial production and daily life.