A novel coal gangue thermal stabilizer and its effect on thermal stability and mechanical properties of poly(vinyl chloride)

Abstract

Nontoxic and efficient coal gangue thermal stabilizer (Y-CG) was prepared by cheap and readily available calcium oxide, coal gangue (CG) and stearic acid(SA). The proposed mechanism of Y-CG thermal stability was studied by XRD, FT-IR, BET and thermal stability test. The results show that when the mass ratio of CG to water was 1:7, the loading of Ca(OH) 2 between CG sheets reached the maximum value of 3.01 mmol/g. The hydrophobic property of the Y-CG surface was better when modified at 75 C for 2 h with 5% SA. With 10% Y-CG, the Congo red test showed thermal stabilization time of PVC improved up to 55.9 min and the torque rheological test showed dynamic thermal stabilization time of PVC improved up to 62.10 min. The TG curves show that Y-CG had little effect on the onset degradation temperature of PVC. Still, Y-CG can absorb HCl and initiate the carbonization of PVC to inhibit degradation. Compared with the commonly used thermal stabilizers, the thermal stability of Y-CG was only slightly worse than that of hydrotalcite thermal stabilizers. The early reaction was that the strong base Ca(OH) 2 in Y-CG adsorbs HCl, and the CaCl 2 was stably loaded in the CG layered structure, which avoided the adverse effects caused by strongly alkaline. The late reaction was that SA and Ca(OH) 2 form weakly alkaline calcium stearate to absorb HCl. At the same time, calcium stearate can also be used as a compatibilizer to improve the compatibility between Y-CG and PVC.

Trends and prospects for thermal stabilizers in polyvinyl chloride

“…In order to achieve practical application, cost competitive thermal stabilizers must be developed. Cao et al [ 57 ] made quite a progress in this aspect. They reported a nontoxic and efficient coal gangue thermal stabilizer (Y‐CG) prepared by cheap and readily available calcium oxide, coal gangue (CG), and stearic acid (SA).…”

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

“…[ 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. [ 3 ] With the public's attention to the environmental friendliness and multi‐function of PVC products, PVC formulations with the advantages of environmental protection, low toxicity, transparent antibacterial are often favored.…”