Heat stabilizers are crucial additives for enhancing the thermal stability of polyvinyl chloride (PVC) during processing. Among the various heat stabilizers available, organic tin compounds have shown remarkable effectiveness. In this study, we investigated the use of dimethyltin dineodecanoate (DMTDN), dibutyltin dineodecanoate (DBTDN), and dioctyltin dineodecanoate (DOTDN) as heat stabilizers for PVC. These compounds were combined with calcium stearate (CaSt2) and zinc stearate (ZnSt2) to improve the thermal stability of PVC materials. The results demonstrated that the thermal stabilization effects of the three tin neodecanoates, when used as standalone heat stabilizers, followed the order: DOTDN > DBTDN > DMTDN. Notably, the thermal stability and lubricity of the three-component heat stabilizer (MTN5-C4Z1, BTN5-C4Z1, and OTN5-C4Z1, respectively), which consisted of the three types of tin neodecanoate, CaSt2, and ZnSt2 in a ratio of 5:4:1, outperformed the use of tin neodecanoate alone. This study offered potential formulations to reduce the application cost of tin neodecanoate as a PVC heat stabilizer.

The contrast enhancement of infrared image is useful and important to the infrared image system. The current techniques of local enhancing exists either over-enhancing or high complexity problems. In this paper, we propose a novel contrast enhancement algorithm which combines histogram equalization based methods (HEBM) and an improved unsharp masking based methods (UMBM). This proposed algorithm uses HEBM to achieve global contrast enhancement and UMBM to achieve local contrast enhancement. Some elaborate strategies are applied to the algorithm to avoid the overenhancement and magnification of noise when contrast is enhanced. The article is organized as follows. First, we review the techniques developed in the literature for contrast enhancement. After then, we introduce the new algorithm in details. The performance of the proposed method is studied on experimental IR data and compared with those yielded by two well established algorithms. The developed algorithm has good performance in global contrast and local contrast enhancement with noise and artifact suppression.

In the production of powder-coating polyester, a strong odor emanates from the water, prompting us to investigate its composition and origin. We studied the process of powder coating epoxy/polyester 50/50, which employs butyl tin tris (2-ethyl hexanoate) as a catalyst. The esterified water was extracted using ethyl acetate. It was analyzed via GC–MS to identify the side reactions and by-products that arise during the tin-catalyzed esterification process. Then we discussed their formation mechanism. Our results indicate that butyl tin tris (2-ethyl hexanoate) triggers side reactions such as cyclization and transesterification, leading to the production of by-products such as heterocyclic compounds (1,4-dioxane), anhydride compounds (propionic anhydride), and others. Notably, the unpleasant odor was found to be derived from propionic anhydride. These findings provide insights into the chemistry of tin-catalyzed esterification and highlight the importance of addressing the formation of unwanted by-products in the production of powder-coating polyester.