硅酸镁和滑石粉的抗磨自修复机理

用四球试验机考察了硅酸镁和滑石粉在凡士林中的抗磨自修复性能,探讨硅酸镁和滑石粉的抗磨自修复机理,认为硅酸镁和滑石粉的抗磨自修复机理是滚珠观点与吸附、渗透和摩擦反应观点的耦合。     

Effects of film tension and contamination on the seal quality of flexible food packaging films made of polypropylene and low density polyethylene blends containing talc filler

Seal integrity and seal strength are important requirements in the heat sealing of flexible packaging. In this article, the influence of talc compounds and different process parameters, such as film tension and contamination on the sealant films consisting of polypropylene and low-density polyethylene blend were investigated. According to the results, increasing the talc ratio from 0% wt to 30% wt positively influenced both hot and cold seal strength. Among different polymer blends having same talc ratio, the sample having the lowest melt flow index (2.84 dg/min at 230°C and 2.16 kg) showed the highest cold seal strength with 9.07 N/25 mm. On the other hand, in the samples with higher melt flow indexes, less seal integrity issues were observed in the presence of contaminants. Elevated film tensions from 0 to 0.4 N/mm² enhanced the seal strengths significantly at the seal initiation temperatures of each film. However, this situation changed at higher operating temperatures due to the increased orientation and brittleness. Besides, in the presence of contaminant coffee particles at the seal interphase, high film tensions adversely affected the seal integrity since the average leakage increased 2.7% for samples A and B, and 7.4% for sample C. In summary, it has been shown that talc incorporation can improve seal strength, high MFI can fill the gaps at the seal interphase and the high levels of film tension (above 0.16 N/mm²) during sealing as well as the contamination need to be avoided to ensure integrity sealing.     

超细滑石粉强化混凝处理废纸造纸废水

比较了分别以PAC和聚合硫酸铁(PFS)为混凝剂时,超细滑石粉(SFT)和PAM对废纸造纸废水混凝处理的助凝效果。用SEM观察了不同絮凝体的微形态。     

Application of factorial model for an optimization of partial replacement of feldspar by talc on the sintering process

This research used a factorial model containing two levels and three variables to evaluate the partial substitution of sodium feldspar (albite) by a talc ore found in abundance in the region of Itaiacoca—Brazil. The model can also be used to verify the influence of initial talc particle size, proportion, and sintering threshold temperature on the following physical properties, such as linear shrinkage, water absorption, bulk density, total porosity, and firing color. In this study, the mechanical strength of the compositions was evaluated by the flexural strength test. The factorial model indicated the sintering temperature as the variable that most affects the samples’ densification and the proportion of talc as the variable that changes the firing color. The experiment that used a higher sintering temperature combined with a coarser talc granulometry presented the highest mechanical strength. When more refined granulometry was used, there was the beginning of an overfire process. Water absorption values in the range of .04% and modulus of rupture of 49 MPa were obtained, confirming the talc's effectiveness as a secondary flux agent suitable for the formulation of ceramic bodies.